Source file src/cmd/compile/internal/ssagen/ssa.go

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ssagen
     6  
     7  import (
     8  	"bufio"
     9  	"bytes"
    10  	"cmp"
    11  	"fmt"
    12  	"go/constant"
    13  	"html"
    14  	"internal/buildcfg"
    15  	"os"
    16  	"path/filepath"
    17  	"slices"
    18  	"strings"
    19  
    20  	"cmd/compile/internal/abi"
    21  	"cmd/compile/internal/base"
    22  	"cmd/compile/internal/ir"
    23  	"cmd/compile/internal/liveness"
    24  	"cmd/compile/internal/objw"
    25  	"cmd/compile/internal/reflectdata"
    26  	"cmd/compile/internal/rttype"
    27  	"cmd/compile/internal/ssa"
    28  	"cmd/compile/internal/staticdata"
    29  	"cmd/compile/internal/typecheck"
    30  	"cmd/compile/internal/types"
    31  	"cmd/internal/obj"
    32  	"cmd/internal/objabi"
    33  	"cmd/internal/src"
    34  	"cmd/internal/sys"
    35  
    36  	rtabi "internal/abi"
    37  )
    38  
    39  var ssaConfig *ssa.Config
    40  var ssaCaches []ssa.Cache
    41  
    42  var ssaDump string     // early copy of $GOSSAFUNC; the func name to dump output for
    43  var ssaDir string      // optional destination for ssa dump file
    44  var ssaDumpStdout bool // whether to dump to stdout
    45  var ssaDumpCFG string  // generate CFGs for these phases
    46  const ssaDumpFile = "ssa.html"
    47  
    48  // ssaDumpInlined holds all inlined functions when ssaDump contains a function name.
    49  var ssaDumpInlined []*ir.Func
    50  
    51  // Maximum size we will aggregate heap allocations of scalar locals.
    52  // Almost certainly can't hurt to be as big as the tiny allocator.
    53  // Might help to be a bit bigger.
    54  const maxAggregatedHeapAllocation = 16
    55  
    56  func DumpInline(fn *ir.Func) {
    57  	if ssaDump != "" && ssaDump == ir.FuncName(fn) {
    58  		ssaDumpInlined = append(ssaDumpInlined, fn)
    59  	}
    60  }
    61  
    62  func InitEnv() {
    63  	ssaDump = os.Getenv("GOSSAFUNC")
    64  	ssaDir = os.Getenv("GOSSADIR")
    65  	if ssaDump != "" {
    66  		if strings.HasSuffix(ssaDump, "+") {
    67  			ssaDump = ssaDump[:len(ssaDump)-1]
    68  			ssaDumpStdout = true
    69  		}
    70  		spl := strings.Split(ssaDump, ":")
    71  		if len(spl) > 1 {
    72  			ssaDump = spl[0]
    73  			ssaDumpCFG = spl[1]
    74  		}
    75  	}
    76  }
    77  
    78  func InitConfig() {
    79  	types_ := ssa.NewTypes()
    80  
    81  	if Arch.SoftFloat {
    82  		softfloatInit()
    83  	}
    84  
    85  	// Generate a few pointer types that are uncommon in the frontend but common in the backend.
    86  	// Caching is disabled in the backend, so generating these here avoids allocations.
    87  	_ = types.NewPtr(types.Types[types.TINTER])                             // *interface{}
    88  	_ = types.NewPtr(types.NewPtr(types.Types[types.TSTRING]))              // **string
    89  	_ = types.NewPtr(types.NewSlice(types.Types[types.TINTER]))             // *[]interface{}
    90  	_ = types.NewPtr(types.NewPtr(types.ByteType))                          // **byte
    91  	_ = types.NewPtr(types.NewSlice(types.ByteType))                        // *[]byte
    92  	_ = types.NewPtr(types.NewSlice(types.Types[types.TSTRING]))            // *[]string
    93  	_ = types.NewPtr(types.NewPtr(types.NewPtr(types.Types[types.TUINT8]))) // ***uint8
    94  	_ = types.NewPtr(types.Types[types.TINT16])                             // *int16
    95  	_ = types.NewPtr(types.Types[types.TINT64])                             // *int64
    96  	_ = types.NewPtr(types.ErrorType)                                       // *error
    97  	if buildcfg.Experiment.SwissMap {
    98  		_ = types.NewPtr(reflectdata.SwissMapType()) // *internal/runtime/maps.Map
    99  	} else {
   100  		_ = types.NewPtr(reflectdata.OldMapType()) // *runtime.hmap
   101  	}
   102  	_ = types.NewPtr(deferstruct()) // *runtime._defer
   103  	types.NewPtrCacheEnabled = false
   104  	ssaConfig = ssa.NewConfig(base.Ctxt.Arch.Name, *types_, base.Ctxt, base.Flag.N == 0, Arch.SoftFloat)
   105  	ssaConfig.Race = base.Flag.Race
   106  	ssaCaches = make([]ssa.Cache, base.Flag.LowerC)
   107  
   108  	// Set up some runtime functions we'll need to call.
   109  	ir.Syms.AssertE2I = typecheck.LookupRuntimeFunc("assertE2I")
   110  	ir.Syms.AssertE2I2 = typecheck.LookupRuntimeFunc("assertE2I2")
   111  	ir.Syms.CgoCheckMemmove = typecheck.LookupRuntimeFunc("cgoCheckMemmove")
   112  	ir.Syms.CgoCheckPtrWrite = typecheck.LookupRuntimeFunc("cgoCheckPtrWrite")
   113  	ir.Syms.CheckPtrAlignment = typecheck.LookupRuntimeFunc("checkptrAlignment")
   114  	ir.Syms.Deferproc = typecheck.LookupRuntimeFunc("deferproc")
   115  	ir.Syms.Deferprocat = typecheck.LookupRuntimeFunc("deferprocat")
   116  	ir.Syms.DeferprocStack = typecheck.LookupRuntimeFunc("deferprocStack")
   117  	ir.Syms.Deferreturn = typecheck.LookupRuntimeFunc("deferreturn")
   118  	ir.Syms.Duffcopy = typecheck.LookupRuntimeFunc("duffcopy")
   119  	ir.Syms.Duffzero = typecheck.LookupRuntimeFunc("duffzero")
   120  	ir.Syms.GCWriteBarrier[0] = typecheck.LookupRuntimeFunc("gcWriteBarrier1")
   121  	ir.Syms.GCWriteBarrier[1] = typecheck.LookupRuntimeFunc("gcWriteBarrier2")
   122  	ir.Syms.GCWriteBarrier[2] = typecheck.LookupRuntimeFunc("gcWriteBarrier3")
   123  	ir.Syms.GCWriteBarrier[3] = typecheck.LookupRuntimeFunc("gcWriteBarrier4")
   124  	ir.Syms.GCWriteBarrier[4] = typecheck.LookupRuntimeFunc("gcWriteBarrier5")
   125  	ir.Syms.GCWriteBarrier[5] = typecheck.LookupRuntimeFunc("gcWriteBarrier6")
   126  	ir.Syms.GCWriteBarrier[6] = typecheck.LookupRuntimeFunc("gcWriteBarrier7")
   127  	ir.Syms.GCWriteBarrier[7] = typecheck.LookupRuntimeFunc("gcWriteBarrier8")
   128  	ir.Syms.Goschedguarded = typecheck.LookupRuntimeFunc("goschedguarded")
   129  	ir.Syms.Growslice = typecheck.LookupRuntimeFunc("growslice")
   130  	ir.Syms.InterfaceSwitch = typecheck.LookupRuntimeFunc("interfaceSwitch")
   131  	ir.Syms.MallocGC = typecheck.LookupRuntimeFunc("mallocgc")
   132  	ir.Syms.Memmove = typecheck.LookupRuntimeFunc("memmove")
   133  	ir.Syms.Msanread = typecheck.LookupRuntimeFunc("msanread")
   134  	ir.Syms.Msanwrite = typecheck.LookupRuntimeFunc("msanwrite")
   135  	ir.Syms.Msanmove = typecheck.LookupRuntimeFunc("msanmove")
   136  	ir.Syms.Asanread = typecheck.LookupRuntimeFunc("asanread")
   137  	ir.Syms.Asanwrite = typecheck.LookupRuntimeFunc("asanwrite")
   138  	ir.Syms.Newobject = typecheck.LookupRuntimeFunc("newobject")
   139  	ir.Syms.Newproc = typecheck.LookupRuntimeFunc("newproc")
   140  	ir.Syms.Panicdivide = typecheck.LookupRuntimeFunc("panicdivide")
   141  	ir.Syms.PanicdottypeE = typecheck.LookupRuntimeFunc("panicdottypeE")
   142  	ir.Syms.PanicdottypeI = typecheck.LookupRuntimeFunc("panicdottypeI")
   143  	ir.Syms.Panicnildottype = typecheck.LookupRuntimeFunc("panicnildottype")
   144  	ir.Syms.Panicoverflow = typecheck.LookupRuntimeFunc("panicoverflow")
   145  	ir.Syms.Panicshift = typecheck.LookupRuntimeFunc("panicshift")
   146  	ir.Syms.Racefuncenter = typecheck.LookupRuntimeFunc("racefuncenter")
   147  	ir.Syms.Racefuncexit = typecheck.LookupRuntimeFunc("racefuncexit")
   148  	ir.Syms.Raceread = typecheck.LookupRuntimeFunc("raceread")
   149  	ir.Syms.Racereadrange = typecheck.LookupRuntimeFunc("racereadrange")
   150  	ir.Syms.Racewrite = typecheck.LookupRuntimeFunc("racewrite")
   151  	ir.Syms.Racewriterange = typecheck.LookupRuntimeFunc("racewriterange")
   152  	ir.Syms.TypeAssert = typecheck.LookupRuntimeFunc("typeAssert")
   153  	ir.Syms.WBZero = typecheck.LookupRuntimeFunc("wbZero")
   154  	ir.Syms.WBMove = typecheck.LookupRuntimeFunc("wbMove")
   155  	ir.Syms.X86HasPOPCNT = typecheck.LookupRuntimeVar("x86HasPOPCNT")         // bool
   156  	ir.Syms.X86HasSSE41 = typecheck.LookupRuntimeVar("x86HasSSE41")           // bool
   157  	ir.Syms.X86HasFMA = typecheck.LookupRuntimeVar("x86HasFMA")               // bool
   158  	ir.Syms.ARMHasVFPv4 = typecheck.LookupRuntimeVar("armHasVFPv4")           // bool
   159  	ir.Syms.ARM64HasATOMICS = typecheck.LookupRuntimeVar("arm64HasATOMICS")   // bool
   160  	ir.Syms.Loong64HasLAMCAS = typecheck.LookupRuntimeVar("loong64HasLAMCAS") // bool
   161  	ir.Syms.Loong64HasLAM_BH = typecheck.LookupRuntimeVar("loong64HasLAM_BH") // bool
   162  	ir.Syms.Loong64HasLSX = typecheck.LookupRuntimeVar("loong64HasLSX")       // bool
   163  	ir.Syms.RISCV64HasZbb = typecheck.LookupRuntimeVar("riscv64HasZbb")       // bool
   164  	ir.Syms.Staticuint64s = typecheck.LookupRuntimeVar("staticuint64s")
   165  	ir.Syms.Typedmemmove = typecheck.LookupRuntimeFunc("typedmemmove")
   166  	ir.Syms.Udiv = typecheck.LookupRuntimeVar("udiv")                 // asm func with special ABI
   167  	ir.Syms.WriteBarrier = typecheck.LookupRuntimeVar("writeBarrier") // struct { bool; ... }
   168  	ir.Syms.Zerobase = typecheck.LookupRuntimeVar("zerobase")
   169  	ir.Syms.ZeroVal = typecheck.LookupRuntimeVar("zeroVal")
   170  
   171  	if Arch.LinkArch.Family == sys.Wasm {
   172  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("goPanicIndex")
   173  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("goPanicIndexU")
   174  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("goPanicSliceAlen")
   175  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("goPanicSliceAlenU")
   176  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("goPanicSliceAcap")
   177  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("goPanicSliceAcapU")
   178  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("goPanicSliceB")
   179  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("goPanicSliceBU")
   180  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("goPanicSlice3Alen")
   181  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("goPanicSlice3AlenU")
   182  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("goPanicSlice3Acap")
   183  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("goPanicSlice3AcapU")
   184  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("goPanicSlice3B")
   185  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("goPanicSlice3BU")
   186  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("goPanicSlice3C")
   187  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("goPanicSlice3CU")
   188  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("goPanicSliceConvert")
   189  	} else {
   190  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("panicIndex")
   191  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("panicIndexU")
   192  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("panicSliceAlen")
   193  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("panicSliceAlenU")
   194  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("panicSliceAcap")
   195  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("panicSliceAcapU")
   196  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("panicSliceB")
   197  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("panicSliceBU")
   198  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("panicSlice3Alen")
   199  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("panicSlice3AlenU")
   200  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("panicSlice3Acap")
   201  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("panicSlice3AcapU")
   202  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("panicSlice3B")
   203  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("panicSlice3BU")
   204  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("panicSlice3C")
   205  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("panicSlice3CU")
   206  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("panicSliceConvert")
   207  	}
   208  	if Arch.LinkArch.PtrSize == 4 {
   209  		ExtendCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeVar("panicExtendIndex")
   210  		ExtendCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeVar("panicExtendIndexU")
   211  		ExtendCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeVar("panicExtendSliceAlen")
   212  		ExtendCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeVar("panicExtendSliceAlenU")
   213  		ExtendCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeVar("panicExtendSliceAcap")
   214  		ExtendCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeVar("panicExtendSliceAcapU")
   215  		ExtendCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeVar("panicExtendSliceB")
   216  		ExtendCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeVar("panicExtendSliceBU")
   217  		ExtendCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeVar("panicExtendSlice3Alen")
   218  		ExtendCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeVar("panicExtendSlice3AlenU")
   219  		ExtendCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeVar("panicExtendSlice3Acap")
   220  		ExtendCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeVar("panicExtendSlice3AcapU")
   221  		ExtendCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeVar("panicExtendSlice3B")
   222  		ExtendCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeVar("panicExtendSlice3BU")
   223  		ExtendCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeVar("panicExtendSlice3C")
   224  		ExtendCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeVar("panicExtendSlice3CU")
   225  	}
   226  
   227  	// Wasm (all asm funcs with special ABIs)
   228  	ir.Syms.WasmDiv = typecheck.LookupRuntimeVar("wasmDiv")
   229  	ir.Syms.WasmTruncS = typecheck.LookupRuntimeVar("wasmTruncS")
   230  	ir.Syms.WasmTruncU = typecheck.LookupRuntimeVar("wasmTruncU")
   231  	ir.Syms.SigPanic = typecheck.LookupRuntimeFunc("sigpanic")
   232  }
   233  
   234  func InitTables() {
   235  	initIntrinsics(nil)
   236  }
   237  
   238  // AbiForBodylessFuncStackMap returns the ABI for a bodyless function's stack map.
   239  // This is not necessarily the ABI used to call it.
   240  // Currently (1.17 dev) such a stack map is always ABI0;
   241  // any ABI wrapper that is present is nosplit, hence a precise
   242  // stack map is not needed there (the parameters survive only long
   243  // enough to call the wrapped assembly function).
   244  // This always returns a freshly copied ABI.
   245  func AbiForBodylessFuncStackMap(fn *ir.Func) *abi.ABIConfig {
   246  	return ssaConfig.ABI0.Copy() // No idea what races will result, be safe
   247  }
   248  
   249  // abiForFunc implements ABI policy for a function, but does not return a copy of the ABI.
   250  // Passing a nil function returns the default ABI based on experiment configuration.
   251  func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig {
   252  	if buildcfg.Experiment.RegabiArgs {
   253  		// Select the ABI based on the function's defining ABI.
   254  		if fn == nil {
   255  			return abi1
   256  		}
   257  		switch fn.ABI {
   258  		case obj.ABI0:
   259  			return abi0
   260  		case obj.ABIInternal:
   261  			// TODO(austin): Clean up the nomenclature here.
   262  			// It's not clear that "abi1" is ABIInternal.
   263  			return abi1
   264  		}
   265  		base.Fatalf("function %v has unknown ABI %v", fn, fn.ABI)
   266  		panic("not reachable")
   267  	}
   268  
   269  	a := abi0
   270  	if fn != nil {
   271  		if fn.Pragma&ir.RegisterParams != 0 { // TODO(register args) remove after register abi is working
   272  			a = abi1
   273  		}
   274  	}
   275  	return a
   276  }
   277  
   278  // emitOpenDeferInfo emits FUNCDATA information about the defers in a function
   279  // that is using open-coded defers.  This funcdata is used to determine the active
   280  // defers in a function and execute those defers during panic processing.
   281  //
   282  // The funcdata is all encoded in varints (since values will almost always be less than
   283  // 128, but stack offsets could potentially be up to 2Gbyte). All "locations" (offsets)
   284  // for stack variables are specified as the number of bytes below varp (pointer to the
   285  // top of the local variables) for their starting address. The format is:
   286  //
   287  //   - Offset of the deferBits variable
   288  //   - Offset of the first closure slot (the rest are laid out consecutively).
   289  func (s *state) emitOpenDeferInfo() {
   290  	firstOffset := s.openDefers[0].closureNode.FrameOffset()
   291  
   292  	// Verify that cmpstackvarlt laid out the slots in order.
   293  	for i, r := range s.openDefers {
   294  		have := r.closureNode.FrameOffset()
   295  		want := firstOffset + int64(i)*int64(types.PtrSize)
   296  		if have != want {
   297  			base.FatalfAt(s.curfn.Pos(), "unexpected frame offset for open-coded defer slot #%v: have %v, want %v", i, have, want)
   298  		}
   299  	}
   300  
   301  	x := base.Ctxt.Lookup(s.curfn.LSym.Name + ".opendefer")
   302  	x.Set(obj.AttrContentAddressable, true)
   303  	s.curfn.LSym.Func().OpenCodedDeferInfo = x
   304  
   305  	off := 0
   306  	off = objw.Uvarint(x, off, uint64(-s.deferBitsTemp.FrameOffset()))
   307  	off = objw.Uvarint(x, off, uint64(-firstOffset))
   308  }
   309  
   310  // buildssa builds an SSA function for fn.
   311  // worker indicates which of the backend workers is doing the processing.
   312  func buildssa(fn *ir.Func, worker int, isPgoHot bool) *ssa.Func {
   313  	name := ir.FuncName(fn)
   314  
   315  	abiSelf := abiForFunc(fn, ssaConfig.ABI0, ssaConfig.ABI1)
   316  
   317  	printssa := false
   318  	// match either a simple name e.g. "(*Reader).Reset", package.name e.g. "compress/gzip.(*Reader).Reset", or subpackage name "gzip.(*Reader).Reset"
   319  	// optionally allows an ABI suffix specification in the GOSSAHASH, e.g. "(*Reader).Reset<0>" etc
   320  	if strings.Contains(ssaDump, name) { // in all the cases the function name is entirely contained within the GOSSAFUNC string.
   321  		nameOptABI := name
   322  		if l := len(ssaDump); l > 1 && ssaDump[l-2] == ',' { // ABI specification
   323  			nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   324  		} else if strings.HasSuffix(ssaDump, ">") { // if they use the linker syntax instead....
   325  			l := len(ssaDump)
   326  			if l >= 3 && ssaDump[l-3] == '<' {
   327  				nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   328  				ssaDump = ssaDump[:l-3] + "," + ssaDump[l-2:l-1]
   329  			}
   330  		}
   331  		pkgDotName := base.Ctxt.Pkgpath + "." + nameOptABI
   332  		printssa = nameOptABI == ssaDump || // "(*Reader).Reset"
   333  			pkgDotName == ssaDump || // "compress/gzip.(*Reader).Reset"
   334  			strings.HasSuffix(pkgDotName, ssaDump) && strings.HasSuffix(pkgDotName, "/"+ssaDump) // "gzip.(*Reader).Reset"
   335  	}
   336  
   337  	var astBuf *bytes.Buffer
   338  	if printssa {
   339  		astBuf = &bytes.Buffer{}
   340  		ir.FDumpList(astBuf, "buildssa-body", fn.Body)
   341  		if ssaDumpStdout {
   342  			fmt.Println("generating SSA for", name)
   343  			fmt.Print(astBuf.String())
   344  		}
   345  	}
   346  
   347  	var s state
   348  	s.pushLine(fn.Pos())
   349  	defer s.popLine()
   350  
   351  	s.hasdefer = fn.HasDefer()
   352  	if fn.Pragma&ir.CgoUnsafeArgs != 0 {
   353  		s.cgoUnsafeArgs = true
   354  	}
   355  	s.checkPtrEnabled = ir.ShouldCheckPtr(fn, 1)
   356  
   357  	if base.Flag.Cfg.Instrumenting && fn.Pragma&ir.Norace == 0 && !fn.Linksym().ABIWrapper() {
   358  		if !base.Flag.Race || !objabi.LookupPkgSpecial(fn.Sym().Pkg.Path).NoRaceFunc {
   359  			s.instrumentMemory = true
   360  		}
   361  		if base.Flag.Race {
   362  			s.instrumentEnterExit = true
   363  		}
   364  	}
   365  
   366  	fe := ssafn{
   367  		curfn: fn,
   368  		log:   printssa && ssaDumpStdout,
   369  	}
   370  	s.curfn = fn
   371  
   372  	cache := &ssaCaches[worker]
   373  	cache.Reset()
   374  
   375  	s.f = ssaConfig.NewFunc(&fe, cache)
   376  	s.config = ssaConfig
   377  	s.f.Type = fn.Type()
   378  	s.f.Name = name
   379  	s.f.PrintOrHtmlSSA = printssa
   380  	if fn.Pragma&ir.Nosplit != 0 {
   381  		s.f.NoSplit = true
   382  	}
   383  	s.f.ABI0 = ssaConfig.ABI0
   384  	s.f.ABI1 = ssaConfig.ABI1
   385  	s.f.ABIDefault = abiForFunc(nil, ssaConfig.ABI0, ssaConfig.ABI1)
   386  	s.f.ABISelf = abiSelf
   387  
   388  	s.panics = map[funcLine]*ssa.Block{}
   389  	s.softFloat = s.config.SoftFloat
   390  
   391  	// Allocate starting block
   392  	s.f.Entry = s.f.NewBlock(ssa.BlockPlain)
   393  	s.f.Entry.Pos = fn.Pos()
   394  	s.f.IsPgoHot = isPgoHot
   395  
   396  	if printssa {
   397  		ssaDF := ssaDumpFile
   398  		if ssaDir != "" {
   399  			ssaDF = filepath.Join(ssaDir, base.Ctxt.Pkgpath+"."+s.f.NameABI()+".html")
   400  			ssaD := filepath.Dir(ssaDF)
   401  			os.MkdirAll(ssaD, 0755)
   402  		}
   403  		s.f.HTMLWriter = ssa.NewHTMLWriter(ssaDF, s.f, ssaDumpCFG)
   404  		// TODO: generate and print a mapping from nodes to values and blocks
   405  		dumpSourcesColumn(s.f.HTMLWriter, fn)
   406  		s.f.HTMLWriter.WriteAST("AST", astBuf)
   407  	}
   408  
   409  	// Allocate starting values
   410  	s.labels = map[string]*ssaLabel{}
   411  	s.fwdVars = map[ir.Node]*ssa.Value{}
   412  	s.startmem = s.entryNewValue0(ssa.OpInitMem, types.TypeMem)
   413  
   414  	s.hasOpenDefers = base.Flag.N == 0 && s.hasdefer && !s.curfn.OpenCodedDeferDisallowed()
   415  	switch {
   416  	case base.Debug.NoOpenDefer != 0:
   417  		s.hasOpenDefers = false
   418  	case s.hasOpenDefers && (base.Ctxt.Flag_shared || base.Ctxt.Flag_dynlink) && base.Ctxt.Arch.Name == "386":
   419  		// Don't support open-coded defers for 386 ONLY when using shared
   420  		// libraries, because there is extra code (added by rewriteToUseGot())
   421  		// preceding the deferreturn/ret code that we don't track correctly.
   422  		//
   423  		// TODO this restriction can be removed given adjusted offset in computeDeferReturn in cmd/link/internal/ld/pcln.go
   424  		s.hasOpenDefers = false
   425  	}
   426  	if s.hasOpenDefers && s.instrumentEnterExit {
   427  		// Skip doing open defers if we need to instrument function
   428  		// returns for the race detector, since we will not generate that
   429  		// code in the case of the extra deferreturn/ret segment.
   430  		s.hasOpenDefers = false
   431  	}
   432  	if s.hasOpenDefers {
   433  		// Similarly, skip if there are any heap-allocated result
   434  		// parameters that need to be copied back to their stack slots.
   435  		for _, f := range s.curfn.Type().Results() {
   436  			if !f.Nname.(*ir.Name).OnStack() {
   437  				s.hasOpenDefers = false
   438  				break
   439  			}
   440  		}
   441  	}
   442  	if s.hasOpenDefers &&
   443  		s.curfn.NumReturns*s.curfn.NumDefers > 15 {
   444  		// Since we are generating defer calls at every exit for
   445  		// open-coded defers, skip doing open-coded defers if there are
   446  		// too many returns (especially if there are multiple defers).
   447  		// Open-coded defers are most important for improving performance
   448  		// for smaller functions (which don't have many returns).
   449  		s.hasOpenDefers = false
   450  	}
   451  
   452  	s.sp = s.entryNewValue0(ssa.OpSP, types.Types[types.TUINTPTR]) // TODO: use generic pointer type (unsafe.Pointer?) instead
   453  	s.sb = s.entryNewValue0(ssa.OpSB, types.Types[types.TUINTPTR])
   454  
   455  	s.startBlock(s.f.Entry)
   456  	s.vars[memVar] = s.startmem
   457  	if s.hasOpenDefers {
   458  		// Create the deferBits variable and stack slot.  deferBits is a
   459  		// bitmask showing which of the open-coded defers in this function
   460  		// have been activated.
   461  		deferBitsTemp := typecheck.TempAt(src.NoXPos, s.curfn, types.Types[types.TUINT8])
   462  		deferBitsTemp.SetAddrtaken(true)
   463  		s.deferBitsTemp = deferBitsTemp
   464  		// For this value, AuxInt is initialized to zero by default
   465  		startDeferBits := s.entryNewValue0(ssa.OpConst8, types.Types[types.TUINT8])
   466  		s.vars[deferBitsVar] = startDeferBits
   467  		s.deferBitsAddr = s.addr(deferBitsTemp)
   468  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, startDeferBits)
   469  		// Make sure that the deferBits stack slot is kept alive (for use
   470  		// by panics) and stores to deferBits are not eliminated, even if
   471  		// all checking code on deferBits in the function exit can be
   472  		// eliminated, because the defer statements were all
   473  		// unconditional.
   474  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, deferBitsTemp, s.mem(), false)
   475  	}
   476  
   477  	var params *abi.ABIParamResultInfo
   478  	params = s.f.ABISelf.ABIAnalyze(fn.Type(), true)
   479  
   480  	// The backend's stackframe pass prunes away entries from the fn's
   481  	// Dcl list, including PARAMOUT nodes that correspond to output
   482  	// params passed in registers. Walk the Dcl list and capture these
   483  	// nodes to a side list, so that we'll have them available during
   484  	// DWARF-gen later on. See issue 48573 for more details.
   485  	var debugInfo ssa.FuncDebug
   486  	for _, n := range fn.Dcl {
   487  		if n.Class == ir.PPARAMOUT && n.IsOutputParamInRegisters() {
   488  			debugInfo.RegOutputParams = append(debugInfo.RegOutputParams, n)
   489  		}
   490  	}
   491  	fn.DebugInfo = &debugInfo
   492  
   493  	// Generate addresses of local declarations
   494  	s.decladdrs = map[*ir.Name]*ssa.Value{}
   495  	for _, n := range fn.Dcl {
   496  		switch n.Class {
   497  		case ir.PPARAM:
   498  			// Be aware that blank and unnamed input parameters will not appear here, but do appear in the type
   499  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   500  		case ir.PPARAMOUT:
   501  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   502  		case ir.PAUTO:
   503  			// processed at each use, to prevent Addr coming
   504  			// before the decl.
   505  		default:
   506  			s.Fatalf("local variable with class %v unimplemented", n.Class)
   507  		}
   508  	}
   509  
   510  	s.f.OwnAux = ssa.OwnAuxCall(fn.LSym, params)
   511  
   512  	// Populate SSAable arguments.
   513  	for _, n := range fn.Dcl {
   514  		if n.Class == ir.PPARAM {
   515  			if s.canSSA(n) {
   516  				v := s.newValue0A(ssa.OpArg, n.Type(), n)
   517  				s.vars[n] = v
   518  				s.addNamedValue(n, v) // This helps with debugging information, not needed for compilation itself.
   519  			} else { // address was taken AND/OR too large for SSA
   520  				paramAssignment := ssa.ParamAssignmentForArgName(s.f, n)
   521  				if len(paramAssignment.Registers) > 0 {
   522  					if ssa.CanSSA(n.Type()) { // SSA-able type, so address was taken -- receive value in OpArg, DO NOT bind to var, store immediately to memory.
   523  						v := s.newValue0A(ssa.OpArg, n.Type(), n)
   524  						s.store(n.Type(), s.decladdrs[n], v)
   525  					} else { // Too big for SSA.
   526  						// Brute force, and early, do a bunch of stores from registers
   527  						// Note that expand calls knows about this and doesn't trouble itself with larger-than-SSA-able Args in registers.
   528  						s.storeParameterRegsToStack(s.f.ABISelf, paramAssignment, n, s.decladdrs[n], false)
   529  					}
   530  				}
   531  			}
   532  		}
   533  	}
   534  
   535  	// Populate closure variables.
   536  	if fn.Needctxt() {
   537  		clo := s.entryNewValue0(ssa.OpGetClosurePtr, s.f.Config.Types.BytePtr)
   538  		if fn.RangeParent != nil && base.Flag.N != 0 {
   539  			// For a range body closure, keep its closure pointer live on the
   540  			// stack with a special name, so the debugger can look for it and
   541  			// find the parent frame.
   542  			sym := &types.Sym{Name: ".closureptr", Pkg: types.LocalPkg}
   543  			cloSlot := s.curfn.NewLocal(src.NoXPos, sym, s.f.Config.Types.BytePtr)
   544  			cloSlot.SetUsed(true)
   545  			cloSlot.SetEsc(ir.EscNever)
   546  			cloSlot.SetAddrtaken(true)
   547  			s.f.CloSlot = cloSlot
   548  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, cloSlot, s.mem(), false)
   549  			addr := s.addr(cloSlot)
   550  			s.store(s.f.Config.Types.BytePtr, addr, clo)
   551  			// Keep it from being dead-store eliminated.
   552  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, cloSlot, s.mem(), false)
   553  		}
   554  		csiter := typecheck.NewClosureStructIter(fn.ClosureVars)
   555  		for {
   556  			n, typ, offset := csiter.Next()
   557  			if n == nil {
   558  				break
   559  			}
   560  
   561  			ptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(typ), offset, clo)
   562  
   563  			// If n is a small variable captured by value, promote
   564  			// it to PAUTO so it can be converted to SSA.
   565  			//
   566  			// Note: While we never capture a variable by value if
   567  			// the user took its address, we may have generated
   568  			// runtime calls that did (#43701). Since we don't
   569  			// convert Addrtaken variables to SSA anyway, no point
   570  			// in promoting them either.
   571  			if n.Byval() && !n.Addrtaken() && ssa.CanSSA(n.Type()) {
   572  				n.Class = ir.PAUTO
   573  				fn.Dcl = append(fn.Dcl, n)
   574  				s.assign(n, s.load(n.Type(), ptr), false, 0)
   575  				continue
   576  			}
   577  
   578  			if !n.Byval() {
   579  				ptr = s.load(typ, ptr)
   580  			}
   581  			s.setHeapaddr(fn.Pos(), n, ptr)
   582  		}
   583  	}
   584  
   585  	// Convert the AST-based IR to the SSA-based IR
   586  	if s.instrumentEnterExit {
   587  		s.rtcall(ir.Syms.Racefuncenter, true, nil, s.newValue0(ssa.OpGetCallerPC, types.Types[types.TUINTPTR]))
   588  	}
   589  	s.zeroResults()
   590  	s.paramsToHeap()
   591  	s.stmtList(fn.Body)
   592  
   593  	// fallthrough to exit
   594  	if s.curBlock != nil {
   595  		s.pushLine(fn.Endlineno)
   596  		s.exit()
   597  		s.popLine()
   598  	}
   599  
   600  	for _, b := range s.f.Blocks {
   601  		if b.Pos != src.NoXPos {
   602  			s.updateUnsetPredPos(b)
   603  		}
   604  	}
   605  
   606  	s.f.HTMLWriter.WritePhase("before insert phis", "before insert phis")
   607  
   608  	s.insertPhis()
   609  
   610  	// Main call to ssa package to compile function
   611  	ssa.Compile(s.f)
   612  
   613  	fe.AllocFrame(s.f)
   614  
   615  	if len(s.openDefers) != 0 {
   616  		s.emitOpenDeferInfo()
   617  	}
   618  
   619  	// Record incoming parameter spill information for morestack calls emitted in the assembler.
   620  	// This is done here, using all the parameters (used, partially used, and unused) because
   621  	// it mimics the behavior of the former ABI (everything stored) and because it's not 100%
   622  	// clear if naming conventions are respected in autogenerated code.
   623  	// TODO figure out exactly what's unused, don't spill it. Make liveness fine-grained, also.
   624  	for _, p := range params.InParams() {
   625  		typs, offs := p.RegisterTypesAndOffsets()
   626  		for i, t := range typs {
   627  			o := offs[i]                // offset within parameter
   628  			fo := p.FrameOffset(params) // offset of parameter in frame
   629  			reg := ssa.ObjRegForAbiReg(p.Registers[i], s.f.Config)
   630  			s.f.RegArgs = append(s.f.RegArgs, ssa.Spill{Reg: reg, Offset: fo + o, Type: t})
   631  		}
   632  	}
   633  
   634  	return s.f
   635  }
   636  
   637  func (s *state) storeParameterRegsToStack(abi *abi.ABIConfig, paramAssignment *abi.ABIParamAssignment, n *ir.Name, addr *ssa.Value, pointersOnly bool) {
   638  	typs, offs := paramAssignment.RegisterTypesAndOffsets()
   639  	for i, t := range typs {
   640  		if pointersOnly && !t.IsPtrShaped() {
   641  			continue
   642  		}
   643  		r := paramAssignment.Registers[i]
   644  		o := offs[i]
   645  		op, reg := ssa.ArgOpAndRegisterFor(r, abi)
   646  		aux := &ssa.AuxNameOffset{Name: n, Offset: o}
   647  		v := s.newValue0I(op, t, reg)
   648  		v.Aux = aux
   649  		p := s.newValue1I(ssa.OpOffPtr, types.NewPtr(t), o, addr)
   650  		s.store(t, p, v)
   651  	}
   652  }
   653  
   654  // zeroResults zeros the return values at the start of the function.
   655  // We need to do this very early in the function.  Defer might stop a
   656  // panic and show the return values as they exist at the time of
   657  // panic.  For precise stacks, the garbage collector assumes results
   658  // are always live, so we need to zero them before any allocations,
   659  // even allocations to move params/results to the heap.
   660  func (s *state) zeroResults() {
   661  	for _, f := range s.curfn.Type().Results() {
   662  		n := f.Nname.(*ir.Name)
   663  		if !n.OnStack() {
   664  			// The local which points to the return value is the
   665  			// thing that needs zeroing. This is already handled
   666  			// by a Needzero annotation in plive.go:(*liveness).epilogue.
   667  			continue
   668  		}
   669  		// Zero the stack location containing f.
   670  		if typ := n.Type(); ssa.CanSSA(typ) {
   671  			s.assign(n, s.zeroVal(typ), false, 0)
   672  		} else {
   673  			if typ.HasPointers() || ssa.IsMergeCandidate(n) {
   674  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
   675  			}
   676  			s.zero(n.Type(), s.decladdrs[n])
   677  		}
   678  	}
   679  }
   680  
   681  // paramsToHeap produces code to allocate memory for heap-escaped parameters
   682  // and to copy non-result parameters' values from the stack.
   683  func (s *state) paramsToHeap() {
   684  	do := func(params []*types.Field) {
   685  		for _, f := range params {
   686  			if f.Nname == nil {
   687  				continue // anonymous or blank parameter
   688  			}
   689  			n := f.Nname.(*ir.Name)
   690  			if ir.IsBlank(n) || n.OnStack() {
   691  				continue
   692  			}
   693  			s.newHeapaddr(n)
   694  			if n.Class == ir.PPARAM {
   695  				s.move(n.Type(), s.expr(n.Heapaddr), s.decladdrs[n])
   696  			}
   697  		}
   698  	}
   699  
   700  	typ := s.curfn.Type()
   701  	do(typ.Recvs())
   702  	do(typ.Params())
   703  	do(typ.Results())
   704  }
   705  
   706  // allocSizeAndAlign returns the size and alignment of t.
   707  // Normally just t.Size() and t.Alignment(), but there
   708  // is a special case to handle 64-bit atomics on 32-bit systems.
   709  func allocSizeAndAlign(t *types.Type) (int64, int64) {
   710  	size, align := t.Size(), t.Alignment()
   711  	if types.PtrSize == 4 && align == 4 && size >= 8 {
   712  		// For 64-bit atomics on 32-bit systems.
   713  		size = types.RoundUp(size, 8)
   714  		align = 8
   715  	}
   716  	return size, align
   717  }
   718  func allocSize(t *types.Type) int64 {
   719  	size, _ := allocSizeAndAlign(t)
   720  	return size
   721  }
   722  func allocAlign(t *types.Type) int64 {
   723  	_, align := allocSizeAndAlign(t)
   724  	return align
   725  }
   726  
   727  // newHeapaddr allocates heap memory for n and sets its heap address.
   728  func (s *state) newHeapaddr(n *ir.Name) {
   729  	size := allocSize(n.Type())
   730  	if n.Type().HasPointers() || size >= maxAggregatedHeapAllocation || size == 0 {
   731  		s.setHeapaddr(n.Pos(), n, s.newObject(n.Type(), nil))
   732  		return
   733  	}
   734  
   735  	// Do we have room together with our pending allocations?
   736  	// If not, flush all the current ones.
   737  	var used int64
   738  	for _, v := range s.pendingHeapAllocations {
   739  		used += allocSize(v.Type.Elem())
   740  	}
   741  	if used+size > maxAggregatedHeapAllocation {
   742  		s.flushPendingHeapAllocations()
   743  	}
   744  
   745  	var allocCall *ssa.Value // (SelectN [0] (call of runtime.newobject))
   746  	if len(s.pendingHeapAllocations) == 0 {
   747  		// Make an allocation, but the type being allocated is just
   748  		// the first pending object. We will come back and update it
   749  		// later if needed.
   750  		allocCall = s.newObject(n.Type(), nil)
   751  	} else {
   752  		allocCall = s.pendingHeapAllocations[0].Args[0]
   753  	}
   754  	// v is an offset to the shared allocation. Offsets are dummy 0s for now.
   755  	v := s.newValue1I(ssa.OpOffPtr, n.Type().PtrTo(), 0, allocCall)
   756  
   757  	// Add to list of pending allocations.
   758  	s.pendingHeapAllocations = append(s.pendingHeapAllocations, v)
   759  
   760  	// Finally, record for posterity.
   761  	s.setHeapaddr(n.Pos(), n, v)
   762  }
   763  
   764  func (s *state) flushPendingHeapAllocations() {
   765  	pending := s.pendingHeapAllocations
   766  	if len(pending) == 0 {
   767  		return // nothing to do
   768  	}
   769  	s.pendingHeapAllocations = nil // reset state
   770  	ptr := pending[0].Args[0]      // The SelectN [0] op
   771  	call := ptr.Args[0]            // The runtime.newobject call
   772  
   773  	if len(pending) == 1 {
   774  		// Just a single object, do a standard allocation.
   775  		v := pending[0]
   776  		v.Op = ssa.OpCopy // instead of OffPtr [0]
   777  		return
   778  	}
   779  
   780  	// Sort in decreasing alignment.
   781  	// This way we never have to worry about padding.
   782  	// (Stable not required; just cleaner to keep program order among equal alignments.)
   783  	slices.SortStableFunc(pending, func(x, y *ssa.Value) int {
   784  		return cmp.Compare(allocAlign(y.Type.Elem()), allocAlign(x.Type.Elem()))
   785  	})
   786  
   787  	// Figure out how much data we need allocate.
   788  	var size int64
   789  	for _, v := range pending {
   790  		v.AuxInt = size // Adjust OffPtr to the right value while we are here.
   791  		size += allocSize(v.Type.Elem())
   792  	}
   793  	align := allocAlign(pending[0].Type.Elem())
   794  	size = types.RoundUp(size, align)
   795  
   796  	// Convert newObject call to a mallocgc call.
   797  	args := []*ssa.Value{
   798  		s.constInt(types.Types[types.TUINTPTR], size),
   799  		s.constNil(call.Args[0].Type), // a nil *runtime._type
   800  		s.constBool(true),             // needZero TODO: false is ok?
   801  		call.Args[1],                  // memory
   802  	}
   803  	call.Aux = ssa.StaticAuxCall(ir.Syms.MallocGC, s.f.ABIDefault.ABIAnalyzeTypes(
   804  		[]*types.Type{args[0].Type, args[1].Type, args[2].Type},
   805  		[]*types.Type{types.Types[types.TUNSAFEPTR]},
   806  	))
   807  	call.AuxInt = 4 * s.config.PtrSize // arg+results size, uintptr/ptr/bool/ptr
   808  	call.SetArgs4(args[0], args[1], args[2], args[3])
   809  	// TODO: figure out how to pass alignment to runtime
   810  
   811  	call.Type = types.NewTuple(types.Types[types.TUNSAFEPTR], types.TypeMem)
   812  	ptr.Type = types.Types[types.TUNSAFEPTR]
   813  }
   814  
   815  // setHeapaddr allocates a new PAUTO variable to store ptr (which must be non-nil)
   816  // and then sets it as n's heap address.
   817  func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
   818  	if !ptr.Type.IsPtr() || !types.Identical(n.Type(), ptr.Type.Elem()) {
   819  		base.FatalfAt(n.Pos(), "setHeapaddr %L with type %v", n, ptr.Type)
   820  	}
   821  
   822  	// Declare variable to hold address.
   823  	sym := &types.Sym{Name: "&" + n.Sym().Name, Pkg: types.LocalPkg}
   824  	addr := s.curfn.NewLocal(pos, sym, types.NewPtr(n.Type()))
   825  	addr.SetUsed(true)
   826  	types.CalcSize(addr.Type())
   827  
   828  	if n.Class == ir.PPARAMOUT {
   829  		addr.SetIsOutputParamHeapAddr(true)
   830  	}
   831  
   832  	n.Heapaddr = addr
   833  	s.assign(addr, ptr, false, 0)
   834  }
   835  
   836  // newObject returns an SSA value denoting new(typ).
   837  func (s *state) newObject(typ *types.Type, rtype *ssa.Value) *ssa.Value {
   838  	if typ.Size() == 0 {
   839  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   840  	}
   841  	if rtype == nil {
   842  		rtype = s.reflectType(typ)
   843  	}
   844  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
   845  }
   846  
   847  func (s *state) checkPtrAlignment(n *ir.ConvExpr, v *ssa.Value, count *ssa.Value) {
   848  	if !n.Type().IsPtr() {
   849  		s.Fatalf("expected pointer type: %v", n.Type())
   850  	}
   851  	elem, rtypeExpr := n.Type().Elem(), n.ElemRType
   852  	if count != nil {
   853  		if !elem.IsArray() {
   854  			s.Fatalf("expected array type: %v", elem)
   855  		}
   856  		elem, rtypeExpr = elem.Elem(), n.ElemElemRType
   857  	}
   858  	size := elem.Size()
   859  	// Casting from larger type to smaller one is ok, so for smallest type, do nothing.
   860  	if elem.Alignment() == 1 && (size == 0 || size == 1 || count == nil) {
   861  		return
   862  	}
   863  	if count == nil {
   864  		count = s.constInt(types.Types[types.TUINTPTR], 1)
   865  	}
   866  	if count.Type.Size() != s.config.PtrSize {
   867  		s.Fatalf("expected count fit to a uintptr size, have: %d, want: %d", count.Type.Size(), s.config.PtrSize)
   868  	}
   869  	var rtype *ssa.Value
   870  	if rtypeExpr != nil {
   871  		rtype = s.expr(rtypeExpr)
   872  	} else {
   873  		rtype = s.reflectType(elem)
   874  	}
   875  	s.rtcall(ir.Syms.CheckPtrAlignment, true, nil, v, rtype, count)
   876  }
   877  
   878  // reflectType returns an SSA value representing a pointer to typ's
   879  // reflection type descriptor.
   880  func (s *state) reflectType(typ *types.Type) *ssa.Value {
   881  	// TODO(mdempsky): Make this Fatalf under Unified IR; frontend needs
   882  	// to supply RType expressions.
   883  	lsym := reflectdata.TypeLinksym(typ)
   884  	return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(types.Types[types.TUINT8]), lsym, s.sb)
   885  }
   886  
   887  func dumpSourcesColumn(writer *ssa.HTMLWriter, fn *ir.Func) {
   888  	// Read sources of target function fn.
   889  	fname := base.Ctxt.PosTable.Pos(fn.Pos()).Filename()
   890  	targetFn, err := readFuncLines(fname, fn.Pos().Line(), fn.Endlineno.Line())
   891  	if err != nil {
   892  		writer.Logf("cannot read sources for function %v: %v", fn, err)
   893  	}
   894  
   895  	// Read sources of inlined functions.
   896  	var inlFns []*ssa.FuncLines
   897  	for _, fi := range ssaDumpInlined {
   898  		elno := fi.Endlineno
   899  		fname := base.Ctxt.PosTable.Pos(fi.Pos()).Filename()
   900  		fnLines, err := readFuncLines(fname, fi.Pos().Line(), elno.Line())
   901  		if err != nil {
   902  			writer.Logf("cannot read sources for inlined function %v: %v", fi, err)
   903  			continue
   904  		}
   905  		inlFns = append(inlFns, fnLines)
   906  	}
   907  
   908  	slices.SortFunc(inlFns, ssa.ByTopoCmp)
   909  	if targetFn != nil {
   910  		inlFns = append([]*ssa.FuncLines{targetFn}, inlFns...)
   911  	}
   912  
   913  	writer.WriteSources("sources", inlFns)
   914  }
   915  
   916  func readFuncLines(file string, start, end uint) (*ssa.FuncLines, error) {
   917  	f, err := os.Open(os.ExpandEnv(file))
   918  	if err != nil {
   919  		return nil, err
   920  	}
   921  	defer f.Close()
   922  	var lines []string
   923  	ln := uint(1)
   924  	scanner := bufio.NewScanner(f)
   925  	for scanner.Scan() && ln <= end {
   926  		if ln >= start {
   927  			lines = append(lines, scanner.Text())
   928  		}
   929  		ln++
   930  	}
   931  	return &ssa.FuncLines{Filename: file, StartLineno: start, Lines: lines}, nil
   932  }
   933  
   934  // updateUnsetPredPos propagates the earliest-value position information for b
   935  // towards all of b's predecessors that need a position, and recurs on that
   936  // predecessor if its position is updated. B should have a non-empty position.
   937  func (s *state) updateUnsetPredPos(b *ssa.Block) {
   938  	if b.Pos == src.NoXPos {
   939  		s.Fatalf("Block %s should have a position", b)
   940  	}
   941  	bestPos := src.NoXPos
   942  	for _, e := range b.Preds {
   943  		p := e.Block()
   944  		if !p.LackingPos() {
   945  			continue
   946  		}
   947  		if bestPos == src.NoXPos {
   948  			bestPos = b.Pos
   949  			for _, v := range b.Values {
   950  				if v.LackingPos() {
   951  					continue
   952  				}
   953  				if v.Pos != src.NoXPos {
   954  					// Assume values are still in roughly textual order;
   955  					// TODO: could also seek minimum position?
   956  					bestPos = v.Pos
   957  					break
   958  				}
   959  			}
   960  		}
   961  		p.Pos = bestPos
   962  		s.updateUnsetPredPos(p) // We do not expect long chains of these, thus recursion is okay.
   963  	}
   964  }
   965  
   966  // Information about each open-coded defer.
   967  type openDeferInfo struct {
   968  	// The node representing the call of the defer
   969  	n *ir.CallExpr
   970  	// If defer call is closure call, the address of the argtmp where the
   971  	// closure is stored.
   972  	closure *ssa.Value
   973  	// The node representing the argtmp where the closure is stored - used for
   974  	// function, method, or interface call, to store a closure that panic
   975  	// processing can use for this defer.
   976  	closureNode *ir.Name
   977  }
   978  
   979  type state struct {
   980  	// configuration (arch) information
   981  	config *ssa.Config
   982  
   983  	// function we're building
   984  	f *ssa.Func
   985  
   986  	// Node for function
   987  	curfn *ir.Func
   988  
   989  	// labels in f
   990  	labels map[string]*ssaLabel
   991  
   992  	// unlabeled break and continue statement tracking
   993  	breakTo    *ssa.Block // current target for plain break statement
   994  	continueTo *ssa.Block // current target for plain continue statement
   995  
   996  	// current location where we're interpreting the AST
   997  	curBlock *ssa.Block
   998  
   999  	// variable assignments in the current block (map from variable symbol to ssa value)
  1000  	// *Node is the unique identifier (an ONAME Node) for the variable.
  1001  	// TODO: keep a single varnum map, then make all of these maps slices instead?
  1002  	vars map[ir.Node]*ssa.Value
  1003  
  1004  	// fwdVars are variables that are used before they are defined in the current block.
  1005  	// This map exists just to coalesce multiple references into a single FwdRef op.
  1006  	// *Node is the unique identifier (an ONAME Node) for the variable.
  1007  	fwdVars map[ir.Node]*ssa.Value
  1008  
  1009  	// all defined variables at the end of each block. Indexed by block ID.
  1010  	defvars []map[ir.Node]*ssa.Value
  1011  
  1012  	// addresses of PPARAM and PPARAMOUT variables on the stack.
  1013  	decladdrs map[*ir.Name]*ssa.Value
  1014  
  1015  	// starting values. Memory, stack pointer, and globals pointer
  1016  	startmem *ssa.Value
  1017  	sp       *ssa.Value
  1018  	sb       *ssa.Value
  1019  	// value representing address of where deferBits autotmp is stored
  1020  	deferBitsAddr *ssa.Value
  1021  	deferBitsTemp *ir.Name
  1022  
  1023  	// line number stack. The current line number is top of stack
  1024  	line []src.XPos
  1025  	// the last line number processed; it may have been popped
  1026  	lastPos src.XPos
  1027  
  1028  	// list of panic calls by function name and line number.
  1029  	// Used to deduplicate panic calls.
  1030  	panics map[funcLine]*ssa.Block
  1031  
  1032  	cgoUnsafeArgs       bool
  1033  	hasdefer            bool // whether the function contains a defer statement
  1034  	softFloat           bool
  1035  	hasOpenDefers       bool // whether we are doing open-coded defers
  1036  	checkPtrEnabled     bool // whether to insert checkptr instrumentation
  1037  	instrumentEnterExit bool // whether to instrument function enter/exit
  1038  	instrumentMemory    bool // whether to instrument memory operations
  1039  
  1040  	// If doing open-coded defers, list of info about the defer calls in
  1041  	// scanning order. Hence, at exit we should run these defers in reverse
  1042  	// order of this list
  1043  	openDefers []*openDeferInfo
  1044  	// For open-coded defers, this is the beginning and end blocks of the last
  1045  	// defer exit code that we have generated so far. We use these to share
  1046  	// code between exits if the shareDeferExits option (disabled by default)
  1047  	// is on.
  1048  	lastDeferExit       *ssa.Block // Entry block of last defer exit code we generated
  1049  	lastDeferFinalBlock *ssa.Block // Final block of last defer exit code we generated
  1050  	lastDeferCount      int        // Number of defers encountered at that point
  1051  
  1052  	prevCall *ssa.Value // the previous call; use this to tie results to the call op.
  1053  
  1054  	// List of allocations in the current block that are still pending.
  1055  	// They are all (OffPtr (Select0 (runtime call))) and have the correct types,
  1056  	// but the offsets are not set yet, and the type of the runtime call is also not final.
  1057  	pendingHeapAllocations []*ssa.Value
  1058  
  1059  	// First argument of append calls that could be stack allocated.
  1060  	appendTargets map[ir.Node]bool
  1061  }
  1062  
  1063  type funcLine struct {
  1064  	f    *obj.LSym
  1065  	base *src.PosBase
  1066  	line uint
  1067  }
  1068  
  1069  type ssaLabel struct {
  1070  	target         *ssa.Block // block identified by this label
  1071  	breakTarget    *ssa.Block // block to break to in control flow node identified by this label
  1072  	continueTarget *ssa.Block // block to continue to in control flow node identified by this label
  1073  }
  1074  
  1075  // label returns the label associated with sym, creating it if necessary.
  1076  func (s *state) label(sym *types.Sym) *ssaLabel {
  1077  	lab := s.labels[sym.Name]
  1078  	if lab == nil {
  1079  		lab = new(ssaLabel)
  1080  		s.labels[sym.Name] = lab
  1081  	}
  1082  	return lab
  1083  }
  1084  
  1085  func (s *state) Logf(msg string, args ...interface{}) { s.f.Logf(msg, args...) }
  1086  func (s *state) Log() bool                            { return s.f.Log() }
  1087  func (s *state) Fatalf(msg string, args ...interface{}) {
  1088  	s.f.Frontend().Fatalf(s.peekPos(), msg, args...)
  1089  }
  1090  func (s *state) Warnl(pos src.XPos, msg string, args ...interface{}) { s.f.Warnl(pos, msg, args...) }
  1091  func (s *state) Debug_checknil() bool                                { return s.f.Frontend().Debug_checknil() }
  1092  
  1093  func ssaMarker(name string) *ir.Name {
  1094  	return ir.NewNameAt(base.Pos, &types.Sym{Name: name}, nil)
  1095  }
  1096  
  1097  var (
  1098  	// marker node for the memory variable
  1099  	memVar = ssaMarker("mem")
  1100  
  1101  	// marker nodes for temporary variables
  1102  	ptrVar       = ssaMarker("ptr")
  1103  	lenVar       = ssaMarker("len")
  1104  	capVar       = ssaMarker("cap")
  1105  	typVar       = ssaMarker("typ")
  1106  	okVar        = ssaMarker("ok")
  1107  	deferBitsVar = ssaMarker("deferBits")
  1108  	hashVar      = ssaMarker("hash")
  1109  )
  1110  
  1111  // startBlock sets the current block we're generating code in to b.
  1112  func (s *state) startBlock(b *ssa.Block) {
  1113  	if s.curBlock != nil {
  1114  		s.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
  1115  	}
  1116  	s.curBlock = b
  1117  	s.vars = map[ir.Node]*ssa.Value{}
  1118  	clear(s.fwdVars)
  1119  }
  1120  
  1121  // endBlock marks the end of generating code for the current block.
  1122  // Returns the (former) current block. Returns nil if there is no current
  1123  // block, i.e. if no code flows to the current execution point.
  1124  func (s *state) endBlock() *ssa.Block {
  1125  	b := s.curBlock
  1126  	if b == nil {
  1127  		return nil
  1128  	}
  1129  
  1130  	s.flushPendingHeapAllocations()
  1131  
  1132  	for len(s.defvars) <= int(b.ID) {
  1133  		s.defvars = append(s.defvars, nil)
  1134  	}
  1135  	s.defvars[b.ID] = s.vars
  1136  	s.curBlock = nil
  1137  	s.vars = nil
  1138  	if b.LackingPos() {
  1139  		// Empty plain blocks get the line of their successor (handled after all blocks created),
  1140  		// except for increment blocks in For statements (handled in ssa conversion of OFOR),
  1141  		// and for blocks ending in GOTO/BREAK/CONTINUE.
  1142  		b.Pos = src.NoXPos
  1143  	} else {
  1144  		b.Pos = s.lastPos
  1145  	}
  1146  	return b
  1147  }
  1148  
  1149  // pushLine pushes a line number on the line number stack.
  1150  func (s *state) pushLine(line src.XPos) {
  1151  	if !line.IsKnown() {
  1152  		// the frontend may emit node with line number missing,
  1153  		// use the parent line number in this case.
  1154  		line = s.peekPos()
  1155  		if base.Flag.K != 0 {
  1156  			base.Warn("buildssa: unknown position (line 0)")
  1157  		}
  1158  	} else {
  1159  		s.lastPos = line
  1160  	}
  1161  
  1162  	s.line = append(s.line, line)
  1163  }
  1164  
  1165  // popLine pops the top of the line number stack.
  1166  func (s *state) popLine() {
  1167  	s.line = s.line[:len(s.line)-1]
  1168  }
  1169  
  1170  // peekPos peeks the top of the line number stack.
  1171  func (s *state) peekPos() src.XPos {
  1172  	return s.line[len(s.line)-1]
  1173  }
  1174  
  1175  // newValue0 adds a new value with no arguments to the current block.
  1176  func (s *state) newValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1177  	return s.curBlock.NewValue0(s.peekPos(), op, t)
  1178  }
  1179  
  1180  // newValue0A adds a new value with no arguments and an aux value to the current block.
  1181  func (s *state) newValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1182  	return s.curBlock.NewValue0A(s.peekPos(), op, t, aux)
  1183  }
  1184  
  1185  // newValue0I adds a new value with no arguments and an auxint value to the current block.
  1186  func (s *state) newValue0I(op ssa.Op, t *types.Type, auxint int64) *ssa.Value {
  1187  	return s.curBlock.NewValue0I(s.peekPos(), op, t, auxint)
  1188  }
  1189  
  1190  // newValue1 adds a new value with one argument to the current block.
  1191  func (s *state) newValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1192  	return s.curBlock.NewValue1(s.peekPos(), op, t, arg)
  1193  }
  1194  
  1195  // newValue1A adds a new value with one argument and an aux value to the current block.
  1196  func (s *state) newValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1197  	return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1198  }
  1199  
  1200  // newValue1Apos adds a new value with one argument and an aux value to the current block.
  1201  // isStmt determines whether the created values may be a statement or not
  1202  // (i.e., false means never, yes means maybe).
  1203  func (s *state) newValue1Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value, isStmt bool) *ssa.Value {
  1204  	if isStmt {
  1205  		return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1206  	}
  1207  	return s.curBlock.NewValue1A(s.peekPos().WithNotStmt(), op, t, aux, arg)
  1208  }
  1209  
  1210  // newValue1I adds a new value with one argument and an auxint value to the current block.
  1211  func (s *state) newValue1I(op ssa.Op, t *types.Type, aux int64, arg *ssa.Value) *ssa.Value {
  1212  	return s.curBlock.NewValue1I(s.peekPos(), op, t, aux, arg)
  1213  }
  1214  
  1215  // newValue2 adds a new value with two arguments to the current block.
  1216  func (s *state) newValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1217  	return s.curBlock.NewValue2(s.peekPos(), op, t, arg0, arg1)
  1218  }
  1219  
  1220  // newValue2A adds a new value with two arguments and an aux value to the current block.
  1221  func (s *state) newValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1222  	return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1223  }
  1224  
  1225  // newValue2Apos adds a new value with two arguments and an aux value to the current block.
  1226  // isStmt determines whether the created values may be a statement or not
  1227  // (i.e., false means never, yes means maybe).
  1228  func (s *state) newValue2Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value, isStmt bool) *ssa.Value {
  1229  	if isStmt {
  1230  		return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1231  	}
  1232  	return s.curBlock.NewValue2A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1)
  1233  }
  1234  
  1235  // newValue2I adds a new value with two arguments and an auxint value to the current block.
  1236  func (s *state) newValue2I(op ssa.Op, t *types.Type, aux int64, arg0, arg1 *ssa.Value) *ssa.Value {
  1237  	return s.curBlock.NewValue2I(s.peekPos(), op, t, aux, arg0, arg1)
  1238  }
  1239  
  1240  // newValue3 adds a new value with three arguments to the current block.
  1241  func (s *state) newValue3(op ssa.Op, t *types.Type, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1242  	return s.curBlock.NewValue3(s.peekPos(), op, t, arg0, arg1, arg2)
  1243  }
  1244  
  1245  // newValue3I adds a new value with three arguments and an auxint value to the current block.
  1246  func (s *state) newValue3I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1247  	return s.curBlock.NewValue3I(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1248  }
  1249  
  1250  // newValue3A adds a new value with three arguments and an aux value to the current block.
  1251  func (s *state) newValue3A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1252  	return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1253  }
  1254  
  1255  // newValue3Apos adds a new value with three arguments and an aux value to the current block.
  1256  // isStmt determines whether the created values may be a statement or not
  1257  // (i.e., false means never, yes means maybe).
  1258  func (s *state) newValue3Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value, isStmt bool) *ssa.Value {
  1259  	if isStmt {
  1260  		return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1261  	}
  1262  	return s.curBlock.NewValue3A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1, arg2)
  1263  }
  1264  
  1265  // newValue4 adds a new value with four arguments to the current block.
  1266  func (s *state) newValue4(op ssa.Op, t *types.Type, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1267  	return s.curBlock.NewValue4(s.peekPos(), op, t, arg0, arg1, arg2, arg3)
  1268  }
  1269  
  1270  // newValue4I adds a new value with four arguments and an auxint value to the current block.
  1271  func (s *state) newValue4I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1272  	return s.curBlock.NewValue4I(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1273  }
  1274  
  1275  func (s *state) entryBlock() *ssa.Block {
  1276  	b := s.f.Entry
  1277  	if base.Flag.N > 0 && s.curBlock != nil {
  1278  		// If optimizations are off, allocate in current block instead. Since with -N
  1279  		// we're not doing the CSE or tighten passes, putting lots of stuff in the
  1280  		// entry block leads to O(n^2) entries in the live value map during regalloc.
  1281  		// See issue 45897.
  1282  		b = s.curBlock
  1283  	}
  1284  	return b
  1285  }
  1286  
  1287  // entryNewValue0 adds a new value with no arguments to the entry block.
  1288  func (s *state) entryNewValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1289  	return s.entryBlock().NewValue0(src.NoXPos, op, t)
  1290  }
  1291  
  1292  // entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
  1293  func (s *state) entryNewValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1294  	return s.entryBlock().NewValue0A(src.NoXPos, op, t, aux)
  1295  }
  1296  
  1297  // entryNewValue1 adds a new value with one argument to the entry block.
  1298  func (s *state) entryNewValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1299  	return s.entryBlock().NewValue1(src.NoXPos, op, t, arg)
  1300  }
  1301  
  1302  // entryNewValue1I adds a new value with one argument and an auxint value to the entry block.
  1303  func (s *state) entryNewValue1I(op ssa.Op, t *types.Type, auxint int64, arg *ssa.Value) *ssa.Value {
  1304  	return s.entryBlock().NewValue1I(src.NoXPos, op, t, auxint, arg)
  1305  }
  1306  
  1307  // entryNewValue1A adds a new value with one argument and an aux value to the entry block.
  1308  func (s *state) entryNewValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1309  	return s.entryBlock().NewValue1A(src.NoXPos, op, t, aux, arg)
  1310  }
  1311  
  1312  // entryNewValue2 adds a new value with two arguments to the entry block.
  1313  func (s *state) entryNewValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1314  	return s.entryBlock().NewValue2(src.NoXPos, op, t, arg0, arg1)
  1315  }
  1316  
  1317  // entryNewValue2A adds a new value with two arguments and an aux value to the entry block.
  1318  func (s *state) entryNewValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1319  	return s.entryBlock().NewValue2A(src.NoXPos, op, t, aux, arg0, arg1)
  1320  }
  1321  
  1322  // const* routines add a new const value to the entry block.
  1323  func (s *state) constSlice(t *types.Type) *ssa.Value {
  1324  	return s.f.ConstSlice(t)
  1325  }
  1326  func (s *state) constInterface(t *types.Type) *ssa.Value {
  1327  	return s.f.ConstInterface(t)
  1328  }
  1329  func (s *state) constNil(t *types.Type) *ssa.Value { return s.f.ConstNil(t) }
  1330  func (s *state) constEmptyString(t *types.Type) *ssa.Value {
  1331  	return s.f.ConstEmptyString(t)
  1332  }
  1333  func (s *state) constBool(c bool) *ssa.Value {
  1334  	return s.f.ConstBool(types.Types[types.TBOOL], c)
  1335  }
  1336  func (s *state) constInt8(t *types.Type, c int8) *ssa.Value {
  1337  	return s.f.ConstInt8(t, c)
  1338  }
  1339  func (s *state) constInt16(t *types.Type, c int16) *ssa.Value {
  1340  	return s.f.ConstInt16(t, c)
  1341  }
  1342  func (s *state) constInt32(t *types.Type, c int32) *ssa.Value {
  1343  	return s.f.ConstInt32(t, c)
  1344  }
  1345  func (s *state) constInt64(t *types.Type, c int64) *ssa.Value {
  1346  	return s.f.ConstInt64(t, c)
  1347  }
  1348  func (s *state) constFloat32(t *types.Type, c float64) *ssa.Value {
  1349  	return s.f.ConstFloat32(t, c)
  1350  }
  1351  func (s *state) constFloat64(t *types.Type, c float64) *ssa.Value {
  1352  	return s.f.ConstFloat64(t, c)
  1353  }
  1354  func (s *state) constInt(t *types.Type, c int64) *ssa.Value {
  1355  	if s.config.PtrSize == 8 {
  1356  		return s.constInt64(t, c)
  1357  	}
  1358  	if int64(int32(c)) != c {
  1359  		s.Fatalf("integer constant too big %d", c)
  1360  	}
  1361  	return s.constInt32(t, int32(c))
  1362  }
  1363  func (s *state) constOffPtrSP(t *types.Type, c int64) *ssa.Value {
  1364  	return s.f.ConstOffPtrSP(t, c, s.sp)
  1365  }
  1366  
  1367  // newValueOrSfCall* are wrappers around newValue*, which may create a call to a
  1368  // soft-float runtime function instead (when emitting soft-float code).
  1369  func (s *state) newValueOrSfCall1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1370  	if s.softFloat {
  1371  		if c, ok := s.sfcall(op, arg); ok {
  1372  			return c
  1373  		}
  1374  	}
  1375  	return s.newValue1(op, t, arg)
  1376  }
  1377  func (s *state) newValueOrSfCall2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1378  	if s.softFloat {
  1379  		if c, ok := s.sfcall(op, arg0, arg1); ok {
  1380  			return c
  1381  		}
  1382  	}
  1383  	return s.newValue2(op, t, arg0, arg1)
  1384  }
  1385  
  1386  type instrumentKind uint8
  1387  
  1388  const (
  1389  	instrumentRead = iota
  1390  	instrumentWrite
  1391  	instrumentMove
  1392  )
  1393  
  1394  func (s *state) instrument(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1395  	s.instrument2(t, addr, nil, kind)
  1396  }
  1397  
  1398  // instrumentFields instruments a read/write operation on addr.
  1399  // If it is instrumenting for MSAN or ASAN and t is a struct type, it instruments
  1400  // operation for each field, instead of for the whole struct.
  1401  func (s *state) instrumentFields(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1402  	if !(base.Flag.MSan || base.Flag.ASan) || !t.IsStruct() {
  1403  		s.instrument(t, addr, kind)
  1404  		return
  1405  	}
  1406  	for _, f := range t.Fields() {
  1407  		if f.Sym.IsBlank() {
  1408  			continue
  1409  		}
  1410  		offptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(f.Type), f.Offset, addr)
  1411  		s.instrumentFields(f.Type, offptr, kind)
  1412  	}
  1413  }
  1414  
  1415  func (s *state) instrumentMove(t *types.Type, dst, src *ssa.Value) {
  1416  	if base.Flag.MSan {
  1417  		s.instrument2(t, dst, src, instrumentMove)
  1418  	} else {
  1419  		s.instrument(t, src, instrumentRead)
  1420  		s.instrument(t, dst, instrumentWrite)
  1421  	}
  1422  }
  1423  
  1424  func (s *state) instrument2(t *types.Type, addr, addr2 *ssa.Value, kind instrumentKind) {
  1425  	if !s.instrumentMemory {
  1426  		return
  1427  	}
  1428  
  1429  	w := t.Size()
  1430  	if w == 0 {
  1431  		return // can't race on zero-sized things
  1432  	}
  1433  
  1434  	if ssa.IsSanitizerSafeAddr(addr) {
  1435  		return
  1436  	}
  1437  
  1438  	var fn *obj.LSym
  1439  	needWidth := false
  1440  
  1441  	if addr2 != nil && kind != instrumentMove {
  1442  		panic("instrument2: non-nil addr2 for non-move instrumentation")
  1443  	}
  1444  
  1445  	if base.Flag.MSan {
  1446  		switch kind {
  1447  		case instrumentRead:
  1448  			fn = ir.Syms.Msanread
  1449  		case instrumentWrite:
  1450  			fn = ir.Syms.Msanwrite
  1451  		case instrumentMove:
  1452  			fn = ir.Syms.Msanmove
  1453  		default:
  1454  			panic("unreachable")
  1455  		}
  1456  		needWidth = true
  1457  	} else if base.Flag.Race && t.NumComponents(types.CountBlankFields) > 1 {
  1458  		// for composite objects we have to write every address
  1459  		// because a write might happen to any subobject.
  1460  		// composites with only one element don't have subobjects, though.
  1461  		switch kind {
  1462  		case instrumentRead:
  1463  			fn = ir.Syms.Racereadrange
  1464  		case instrumentWrite:
  1465  			fn = ir.Syms.Racewriterange
  1466  		default:
  1467  			panic("unreachable")
  1468  		}
  1469  		needWidth = true
  1470  	} else if base.Flag.Race {
  1471  		// for non-composite objects we can write just the start
  1472  		// address, as any write must write the first byte.
  1473  		switch kind {
  1474  		case instrumentRead:
  1475  			fn = ir.Syms.Raceread
  1476  		case instrumentWrite:
  1477  			fn = ir.Syms.Racewrite
  1478  		default:
  1479  			panic("unreachable")
  1480  		}
  1481  	} else if base.Flag.ASan {
  1482  		switch kind {
  1483  		case instrumentRead:
  1484  			fn = ir.Syms.Asanread
  1485  		case instrumentWrite:
  1486  			fn = ir.Syms.Asanwrite
  1487  		default:
  1488  			panic("unreachable")
  1489  		}
  1490  		needWidth = true
  1491  	} else {
  1492  		panic("unreachable")
  1493  	}
  1494  
  1495  	args := []*ssa.Value{addr}
  1496  	if addr2 != nil {
  1497  		args = append(args, addr2)
  1498  	}
  1499  	if needWidth {
  1500  		args = append(args, s.constInt(types.Types[types.TUINTPTR], w))
  1501  	}
  1502  	s.rtcall(fn, true, nil, args...)
  1503  }
  1504  
  1505  func (s *state) load(t *types.Type, src *ssa.Value) *ssa.Value {
  1506  	s.instrumentFields(t, src, instrumentRead)
  1507  	return s.rawLoad(t, src)
  1508  }
  1509  
  1510  func (s *state) rawLoad(t *types.Type, src *ssa.Value) *ssa.Value {
  1511  	return s.newValue2(ssa.OpLoad, t, src, s.mem())
  1512  }
  1513  
  1514  func (s *state) store(t *types.Type, dst, val *ssa.Value) {
  1515  	s.vars[memVar] = s.newValue3A(ssa.OpStore, types.TypeMem, t, dst, val, s.mem())
  1516  }
  1517  
  1518  func (s *state) zero(t *types.Type, dst *ssa.Value) {
  1519  	s.instrument(t, dst, instrumentWrite)
  1520  	store := s.newValue2I(ssa.OpZero, types.TypeMem, t.Size(), dst, s.mem())
  1521  	store.Aux = t
  1522  	s.vars[memVar] = store
  1523  }
  1524  
  1525  func (s *state) move(t *types.Type, dst, src *ssa.Value) {
  1526  	s.moveWhichMayOverlap(t, dst, src, false)
  1527  }
  1528  func (s *state) moveWhichMayOverlap(t *types.Type, dst, src *ssa.Value, mayOverlap bool) {
  1529  	s.instrumentMove(t, dst, src)
  1530  	if mayOverlap && t.IsArray() && t.NumElem() > 1 && !ssa.IsInlinableMemmove(dst, src, t.Size(), s.f.Config) {
  1531  		// Normally, when moving Go values of type T from one location to another,
  1532  		// we don't need to worry about partial overlaps. The two Ts must either be
  1533  		// in disjoint (nonoverlapping) memory or in exactly the same location.
  1534  		// There are 2 cases where this isn't true:
  1535  		//  1) Using unsafe you can arrange partial overlaps.
  1536  		//  2) Since Go 1.17, you can use a cast from a slice to a ptr-to-array.
  1537  		//     https://go.dev/ref/spec#Conversions_from_slice_to_array_pointer
  1538  		//     This feature can be used to construct partial overlaps of array types.
  1539  		//       var a [3]int
  1540  		//       p := (*[2]int)(a[:])
  1541  		//       q := (*[2]int)(a[1:])
  1542  		//       *p = *q
  1543  		// We don't care about solving 1. Or at least, we haven't historically
  1544  		// and no one has complained.
  1545  		// For 2, we need to ensure that if there might be partial overlap,
  1546  		// then we can't use OpMove; we must use memmove instead.
  1547  		// (memmove handles partial overlap by copying in the correct
  1548  		// direction. OpMove does not.)
  1549  		//
  1550  		// Note that we have to be careful here not to introduce a call when
  1551  		// we're marshaling arguments to a call or unmarshaling results from a call.
  1552  		// Cases where this is happening must pass mayOverlap to false.
  1553  		// (Currently this only happens when unmarshaling results of a call.)
  1554  		if t.HasPointers() {
  1555  			s.rtcall(ir.Syms.Typedmemmove, true, nil, s.reflectType(t), dst, src)
  1556  			// We would have otherwise implemented this move with straightline code,
  1557  			// including a write barrier. Pretend we issue a write barrier here,
  1558  			// so that the write barrier tests work. (Otherwise they'd need to know
  1559  			// the details of IsInlineableMemmove.)
  1560  			s.curfn.SetWBPos(s.peekPos())
  1561  		} else {
  1562  			s.rtcall(ir.Syms.Memmove, true, nil, dst, src, s.constInt(types.Types[types.TUINTPTR], t.Size()))
  1563  		}
  1564  		ssa.LogLargeCopy(s.f.Name, s.peekPos(), t.Size())
  1565  		return
  1566  	}
  1567  	store := s.newValue3I(ssa.OpMove, types.TypeMem, t.Size(), dst, src, s.mem())
  1568  	store.Aux = t
  1569  	s.vars[memVar] = store
  1570  }
  1571  
  1572  // stmtList converts the statement list n to SSA and adds it to s.
  1573  func (s *state) stmtList(l ir.Nodes) {
  1574  	for _, n := range l {
  1575  		s.stmt(n)
  1576  	}
  1577  }
  1578  
  1579  func peelConvNop(n ir.Node) ir.Node {
  1580  	if n == nil {
  1581  		return n
  1582  	}
  1583  	for n.Op() == ir.OCONVNOP {
  1584  		n = n.(*ir.ConvExpr).X
  1585  	}
  1586  	return n
  1587  }
  1588  
  1589  // stmt converts the statement n to SSA and adds it to s.
  1590  func (s *state) stmt(n ir.Node) {
  1591  	s.pushLine(n.Pos())
  1592  	defer s.popLine()
  1593  
  1594  	// If s.curBlock is nil, and n isn't a label (which might have an associated goto somewhere),
  1595  	// then this code is dead. Stop here.
  1596  	if s.curBlock == nil && n.Op() != ir.OLABEL {
  1597  		return
  1598  	}
  1599  
  1600  	s.stmtList(n.Init())
  1601  	switch n.Op() {
  1602  
  1603  	case ir.OBLOCK:
  1604  		n := n.(*ir.BlockStmt)
  1605  		s.stmtList(n.List)
  1606  
  1607  	case ir.OFALL: // no-op
  1608  
  1609  	// Expression statements
  1610  	case ir.OCALLFUNC:
  1611  		n := n.(*ir.CallExpr)
  1612  		if ir.IsIntrinsicCall(n) {
  1613  			s.intrinsicCall(n)
  1614  			return
  1615  		}
  1616  		fallthrough
  1617  
  1618  	case ir.OCALLINTER:
  1619  		n := n.(*ir.CallExpr)
  1620  		s.callResult(n, callNormal)
  1621  		if n.Op() == ir.OCALLFUNC && n.Fun.Op() == ir.ONAME && n.Fun.(*ir.Name).Class == ir.PFUNC {
  1622  			if fn := n.Fun.Sym().Name; base.Flag.CompilingRuntime && fn == "throw" ||
  1623  				n.Fun.Sym().Pkg == ir.Pkgs.Runtime &&
  1624  					(fn == "throwinit" || fn == "gopanic" || fn == "panicwrap" || fn == "block" ||
  1625  						fn == "panicmakeslicelen" || fn == "panicmakeslicecap" || fn == "panicunsafeslicelen" ||
  1626  						fn == "panicunsafeslicenilptr" || fn == "panicunsafestringlen" || fn == "panicunsafestringnilptr" ||
  1627  						fn == "panicrangestate") {
  1628  				m := s.mem()
  1629  				b := s.endBlock()
  1630  				b.Kind = ssa.BlockExit
  1631  				b.SetControl(m)
  1632  				// TODO: never rewrite OPANIC to OCALLFUNC in the
  1633  				// first place. Need to wait until all backends
  1634  				// go through SSA.
  1635  			}
  1636  		}
  1637  	case ir.ODEFER:
  1638  		n := n.(*ir.GoDeferStmt)
  1639  		if base.Debug.Defer > 0 {
  1640  			var defertype string
  1641  			if s.hasOpenDefers {
  1642  				defertype = "open-coded"
  1643  			} else if n.Esc() == ir.EscNever {
  1644  				defertype = "stack-allocated"
  1645  			} else {
  1646  				defertype = "heap-allocated"
  1647  			}
  1648  			base.WarnfAt(n.Pos(), "%s defer", defertype)
  1649  		}
  1650  		if s.hasOpenDefers {
  1651  			s.openDeferRecord(n.Call.(*ir.CallExpr))
  1652  		} else {
  1653  			d := callDefer
  1654  			if n.Esc() == ir.EscNever && n.DeferAt == nil {
  1655  				d = callDeferStack
  1656  			}
  1657  			s.call(n.Call.(*ir.CallExpr), d, false, n.DeferAt)
  1658  		}
  1659  	case ir.OGO:
  1660  		n := n.(*ir.GoDeferStmt)
  1661  		s.callResult(n.Call.(*ir.CallExpr), callGo)
  1662  
  1663  	case ir.OAS2DOTTYPE:
  1664  		n := n.(*ir.AssignListStmt)
  1665  		var res, resok *ssa.Value
  1666  		if n.Rhs[0].Op() == ir.ODOTTYPE2 {
  1667  			res, resok = s.dottype(n.Rhs[0].(*ir.TypeAssertExpr), true)
  1668  		} else {
  1669  			res, resok = s.dynamicDottype(n.Rhs[0].(*ir.DynamicTypeAssertExpr), true)
  1670  		}
  1671  		deref := false
  1672  		if !ssa.CanSSA(n.Rhs[0].Type()) {
  1673  			if res.Op != ssa.OpLoad {
  1674  				s.Fatalf("dottype of non-load")
  1675  			}
  1676  			mem := s.mem()
  1677  			if res.Args[1] != mem {
  1678  				s.Fatalf("memory no longer live from 2-result dottype load")
  1679  			}
  1680  			deref = true
  1681  			res = res.Args[0]
  1682  		}
  1683  		s.assign(n.Lhs[0], res, deref, 0)
  1684  		s.assign(n.Lhs[1], resok, false, 0)
  1685  		return
  1686  
  1687  	case ir.OAS2FUNC:
  1688  		// We come here only when it is an intrinsic call returning two values.
  1689  		n := n.(*ir.AssignListStmt)
  1690  		call := n.Rhs[0].(*ir.CallExpr)
  1691  		if !ir.IsIntrinsicCall(call) {
  1692  			s.Fatalf("non-intrinsic AS2FUNC not expanded %v", call)
  1693  		}
  1694  		v := s.intrinsicCall(call)
  1695  		v1 := s.newValue1(ssa.OpSelect0, n.Lhs[0].Type(), v)
  1696  		v2 := s.newValue1(ssa.OpSelect1, n.Lhs[1].Type(), v)
  1697  		s.assign(n.Lhs[0], v1, false, 0)
  1698  		s.assign(n.Lhs[1], v2, false, 0)
  1699  		return
  1700  
  1701  	case ir.ODCL:
  1702  		n := n.(*ir.Decl)
  1703  		if v := n.X; v.Esc() == ir.EscHeap {
  1704  			s.newHeapaddr(v)
  1705  		}
  1706  
  1707  	case ir.OLABEL:
  1708  		n := n.(*ir.LabelStmt)
  1709  		sym := n.Label
  1710  		if sym.IsBlank() {
  1711  			// Nothing to do because the label isn't targetable. See issue 52278.
  1712  			break
  1713  		}
  1714  		lab := s.label(sym)
  1715  
  1716  		// The label might already have a target block via a goto.
  1717  		if lab.target == nil {
  1718  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1719  		}
  1720  
  1721  		// Go to that label.
  1722  		// (We pretend "label:" is preceded by "goto label", unless the predecessor is unreachable.)
  1723  		if s.curBlock != nil {
  1724  			b := s.endBlock()
  1725  			b.AddEdgeTo(lab.target)
  1726  		}
  1727  		s.startBlock(lab.target)
  1728  
  1729  	case ir.OGOTO:
  1730  		n := n.(*ir.BranchStmt)
  1731  		sym := n.Label
  1732  
  1733  		lab := s.label(sym)
  1734  		if lab.target == nil {
  1735  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1736  		}
  1737  
  1738  		b := s.endBlock()
  1739  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1740  		b.AddEdgeTo(lab.target)
  1741  
  1742  	case ir.OAS:
  1743  		n := n.(*ir.AssignStmt)
  1744  		if n.X == n.Y && n.X.Op() == ir.ONAME {
  1745  			// An x=x assignment. No point in doing anything
  1746  			// here. In addition, skipping this assignment
  1747  			// prevents generating:
  1748  			//   VARDEF x
  1749  			//   COPY x -> x
  1750  			// which is bad because x is incorrectly considered
  1751  			// dead before the vardef. See issue #14904.
  1752  			return
  1753  		}
  1754  
  1755  		// mayOverlap keeps track of whether the LHS and RHS might
  1756  		// refer to partially overlapping memory. Partial overlapping can
  1757  		// only happen for arrays, see the comment in moveWhichMayOverlap.
  1758  		//
  1759  		// If both sides of the assignment are not dereferences, then partial
  1760  		// overlap can't happen. Partial overlap can only occur only when the
  1761  		// arrays referenced are strictly smaller parts of the same base array.
  1762  		// If one side of the assignment is a full array, then partial overlap
  1763  		// can't happen. (The arrays are either disjoint or identical.)
  1764  		ny := peelConvNop(n.Y)
  1765  		mayOverlap := n.X.Op() == ir.ODEREF && (n.Y != nil && ny.Op() == ir.ODEREF)
  1766  		if ny != nil && ny.Op() == ir.ODEREF {
  1767  			p := peelConvNop(ny.(*ir.StarExpr).X)
  1768  			if p.Op() == ir.OSPTR && p.(*ir.UnaryExpr).X.Type().IsString() {
  1769  				// Pointer fields of strings point to unmodifiable memory.
  1770  				// That memory can't overlap with the memory being written.
  1771  				mayOverlap = false
  1772  			}
  1773  		}
  1774  
  1775  		// Evaluate RHS.
  1776  		rhs := n.Y
  1777  		if rhs != nil {
  1778  			switch rhs.Op() {
  1779  			case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT:
  1780  				// All literals with nonzero fields have already been
  1781  				// rewritten during walk. Any that remain are just T{}
  1782  				// or equivalents. Use the zero value.
  1783  				if !ir.IsZero(rhs) {
  1784  					s.Fatalf("literal with nonzero value in SSA: %v", rhs)
  1785  				}
  1786  				rhs = nil
  1787  			case ir.OAPPEND:
  1788  				rhs := rhs.(*ir.CallExpr)
  1789  				// Check whether we're writing the result of an append back to the same slice.
  1790  				// If so, we handle it specially to avoid write barriers on the fast
  1791  				// (non-growth) path.
  1792  				if !ir.SameSafeExpr(n.X, rhs.Args[0]) || base.Flag.N != 0 {
  1793  					break
  1794  				}
  1795  				// If the slice can be SSA'd, it'll be on the stack,
  1796  				// so there will be no write barriers,
  1797  				// so there's no need to attempt to prevent them.
  1798  				if s.canSSA(n.X) {
  1799  					if base.Debug.Append > 0 { // replicating old diagnostic message
  1800  						base.WarnfAt(n.Pos(), "append: len-only update (in local slice)")
  1801  					}
  1802  					break
  1803  				}
  1804  				if base.Debug.Append > 0 {
  1805  					base.WarnfAt(n.Pos(), "append: len-only update")
  1806  				}
  1807  				s.append(rhs, true)
  1808  				return
  1809  			}
  1810  		}
  1811  
  1812  		if ir.IsBlank(n.X) {
  1813  			// _ = rhs
  1814  			// Just evaluate rhs for side-effects.
  1815  			if rhs != nil {
  1816  				s.expr(rhs)
  1817  			}
  1818  			return
  1819  		}
  1820  
  1821  		var t *types.Type
  1822  		if n.Y != nil {
  1823  			t = n.Y.Type()
  1824  		} else {
  1825  			t = n.X.Type()
  1826  		}
  1827  
  1828  		var r *ssa.Value
  1829  		deref := !ssa.CanSSA(t)
  1830  		if deref {
  1831  			if rhs == nil {
  1832  				r = nil // Signal assign to use OpZero.
  1833  			} else {
  1834  				r = s.addr(rhs)
  1835  			}
  1836  		} else {
  1837  			if rhs == nil {
  1838  				r = s.zeroVal(t)
  1839  			} else {
  1840  				r = s.expr(rhs)
  1841  			}
  1842  		}
  1843  
  1844  		var skip skipMask
  1845  		if rhs != nil && (rhs.Op() == ir.OSLICE || rhs.Op() == ir.OSLICE3 || rhs.Op() == ir.OSLICESTR) && ir.SameSafeExpr(rhs.(*ir.SliceExpr).X, n.X) {
  1846  			// We're assigning a slicing operation back to its source.
  1847  			// Don't write back fields we aren't changing. See issue #14855.
  1848  			rhs := rhs.(*ir.SliceExpr)
  1849  			i, j, k := rhs.Low, rhs.High, rhs.Max
  1850  			if i != nil && (i.Op() == ir.OLITERAL && i.Val().Kind() == constant.Int && ir.Int64Val(i) == 0) {
  1851  				// [0:...] is the same as [:...]
  1852  				i = nil
  1853  			}
  1854  			// TODO: detect defaults for len/cap also.
  1855  			// Currently doesn't really work because (*p)[:len(*p)] appears here as:
  1856  			//    tmp = len(*p)
  1857  			//    (*p)[:tmp]
  1858  			// if j != nil && (j.Op == OLEN && SameSafeExpr(j.Left, n.Left)) {
  1859  			//      j = nil
  1860  			// }
  1861  			// if k != nil && (k.Op == OCAP && SameSafeExpr(k.Left, n.Left)) {
  1862  			//      k = nil
  1863  			// }
  1864  			if i == nil {
  1865  				skip |= skipPtr
  1866  				if j == nil {
  1867  					skip |= skipLen
  1868  				}
  1869  				if k == nil {
  1870  					skip |= skipCap
  1871  				}
  1872  			}
  1873  		}
  1874  
  1875  		s.assignWhichMayOverlap(n.X, r, deref, skip, mayOverlap)
  1876  
  1877  	case ir.OIF:
  1878  		n := n.(*ir.IfStmt)
  1879  		if ir.IsConst(n.Cond, constant.Bool) {
  1880  			s.stmtList(n.Cond.Init())
  1881  			if ir.BoolVal(n.Cond) {
  1882  				s.stmtList(n.Body)
  1883  			} else {
  1884  				s.stmtList(n.Else)
  1885  			}
  1886  			break
  1887  		}
  1888  
  1889  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1890  		var likely int8
  1891  		if n.Likely {
  1892  			likely = 1
  1893  		}
  1894  		var bThen *ssa.Block
  1895  		if len(n.Body) != 0 {
  1896  			bThen = s.f.NewBlock(ssa.BlockPlain)
  1897  		} else {
  1898  			bThen = bEnd
  1899  		}
  1900  		var bElse *ssa.Block
  1901  		if len(n.Else) != 0 {
  1902  			bElse = s.f.NewBlock(ssa.BlockPlain)
  1903  		} else {
  1904  			bElse = bEnd
  1905  		}
  1906  		s.condBranch(n.Cond, bThen, bElse, likely)
  1907  
  1908  		if len(n.Body) != 0 {
  1909  			s.startBlock(bThen)
  1910  			s.stmtList(n.Body)
  1911  			if b := s.endBlock(); b != nil {
  1912  				b.AddEdgeTo(bEnd)
  1913  			}
  1914  		}
  1915  		if len(n.Else) != 0 {
  1916  			s.startBlock(bElse)
  1917  			s.stmtList(n.Else)
  1918  			if b := s.endBlock(); b != nil {
  1919  				b.AddEdgeTo(bEnd)
  1920  			}
  1921  		}
  1922  		s.startBlock(bEnd)
  1923  
  1924  	case ir.ORETURN:
  1925  		n := n.(*ir.ReturnStmt)
  1926  		s.stmtList(n.Results)
  1927  		b := s.exit()
  1928  		b.Pos = s.lastPos.WithIsStmt()
  1929  
  1930  	case ir.OTAILCALL:
  1931  		n := n.(*ir.TailCallStmt)
  1932  		s.callResult(n.Call, callTail)
  1933  		call := s.mem()
  1934  		b := s.endBlock()
  1935  		b.Kind = ssa.BlockRetJmp // could use BlockExit. BlockRetJmp is mostly for clarity.
  1936  		b.SetControl(call)
  1937  
  1938  	case ir.OCONTINUE, ir.OBREAK:
  1939  		n := n.(*ir.BranchStmt)
  1940  		var to *ssa.Block
  1941  		if n.Label == nil {
  1942  			// plain break/continue
  1943  			switch n.Op() {
  1944  			case ir.OCONTINUE:
  1945  				to = s.continueTo
  1946  			case ir.OBREAK:
  1947  				to = s.breakTo
  1948  			}
  1949  		} else {
  1950  			// labeled break/continue; look up the target
  1951  			sym := n.Label
  1952  			lab := s.label(sym)
  1953  			switch n.Op() {
  1954  			case ir.OCONTINUE:
  1955  				to = lab.continueTarget
  1956  			case ir.OBREAK:
  1957  				to = lab.breakTarget
  1958  			}
  1959  		}
  1960  
  1961  		b := s.endBlock()
  1962  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1963  		b.AddEdgeTo(to)
  1964  
  1965  	case ir.OFOR:
  1966  		// OFOR: for Ninit; Left; Right { Nbody }
  1967  		// cond (Left); body (Nbody); incr (Right)
  1968  		n := n.(*ir.ForStmt)
  1969  		base.Assert(!n.DistinctVars) // Should all be rewritten before escape analysis
  1970  		bCond := s.f.NewBlock(ssa.BlockPlain)
  1971  		bBody := s.f.NewBlock(ssa.BlockPlain)
  1972  		bIncr := s.f.NewBlock(ssa.BlockPlain)
  1973  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1974  
  1975  		// ensure empty for loops have correct position; issue #30167
  1976  		bBody.Pos = n.Pos()
  1977  
  1978  		// first, jump to condition test
  1979  		b := s.endBlock()
  1980  		b.AddEdgeTo(bCond)
  1981  
  1982  		// generate code to test condition
  1983  		s.startBlock(bCond)
  1984  		if n.Cond != nil {
  1985  			s.condBranch(n.Cond, bBody, bEnd, 1)
  1986  		} else {
  1987  			b := s.endBlock()
  1988  			b.Kind = ssa.BlockPlain
  1989  			b.AddEdgeTo(bBody)
  1990  		}
  1991  
  1992  		// set up for continue/break in body
  1993  		prevContinue := s.continueTo
  1994  		prevBreak := s.breakTo
  1995  		s.continueTo = bIncr
  1996  		s.breakTo = bEnd
  1997  		var lab *ssaLabel
  1998  		if sym := n.Label; sym != nil {
  1999  			// labeled for loop
  2000  			lab = s.label(sym)
  2001  			lab.continueTarget = bIncr
  2002  			lab.breakTarget = bEnd
  2003  		}
  2004  
  2005  		// generate body
  2006  		s.startBlock(bBody)
  2007  		s.stmtList(n.Body)
  2008  
  2009  		// tear down continue/break
  2010  		s.continueTo = prevContinue
  2011  		s.breakTo = prevBreak
  2012  		if lab != nil {
  2013  			lab.continueTarget = nil
  2014  			lab.breakTarget = nil
  2015  		}
  2016  
  2017  		// done with body, goto incr
  2018  		if b := s.endBlock(); b != nil {
  2019  			b.AddEdgeTo(bIncr)
  2020  		}
  2021  
  2022  		// generate incr
  2023  		s.startBlock(bIncr)
  2024  		if n.Post != nil {
  2025  			s.stmt(n.Post)
  2026  		}
  2027  		if b := s.endBlock(); b != nil {
  2028  			b.AddEdgeTo(bCond)
  2029  			// It can happen that bIncr ends in a block containing only VARKILL,
  2030  			// and that muddles the debugging experience.
  2031  			if b.Pos == src.NoXPos {
  2032  				b.Pos = bCond.Pos
  2033  			}
  2034  		}
  2035  
  2036  		s.startBlock(bEnd)
  2037  
  2038  	case ir.OSWITCH, ir.OSELECT:
  2039  		// These have been mostly rewritten by the front end into their Nbody fields.
  2040  		// Our main task is to correctly hook up any break statements.
  2041  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  2042  
  2043  		prevBreak := s.breakTo
  2044  		s.breakTo = bEnd
  2045  		var sym *types.Sym
  2046  		var body ir.Nodes
  2047  		if n.Op() == ir.OSWITCH {
  2048  			n := n.(*ir.SwitchStmt)
  2049  			sym = n.Label
  2050  			body = n.Compiled
  2051  		} else {
  2052  			n := n.(*ir.SelectStmt)
  2053  			sym = n.Label
  2054  			body = n.Compiled
  2055  		}
  2056  
  2057  		var lab *ssaLabel
  2058  		if sym != nil {
  2059  			// labeled
  2060  			lab = s.label(sym)
  2061  			lab.breakTarget = bEnd
  2062  		}
  2063  
  2064  		// generate body code
  2065  		s.stmtList(body)
  2066  
  2067  		s.breakTo = prevBreak
  2068  		if lab != nil {
  2069  			lab.breakTarget = nil
  2070  		}
  2071  
  2072  		// walk adds explicit OBREAK nodes to the end of all reachable code paths.
  2073  		// If we still have a current block here, then mark it unreachable.
  2074  		if s.curBlock != nil {
  2075  			m := s.mem()
  2076  			b := s.endBlock()
  2077  			b.Kind = ssa.BlockExit
  2078  			b.SetControl(m)
  2079  		}
  2080  		s.startBlock(bEnd)
  2081  
  2082  	case ir.OJUMPTABLE:
  2083  		n := n.(*ir.JumpTableStmt)
  2084  
  2085  		// Make blocks we'll need.
  2086  		jt := s.f.NewBlock(ssa.BlockJumpTable)
  2087  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  2088  
  2089  		// The only thing that needs evaluating is the index we're looking up.
  2090  		idx := s.expr(n.Idx)
  2091  		unsigned := idx.Type.IsUnsigned()
  2092  
  2093  		// Extend so we can do everything in uintptr arithmetic.
  2094  		t := types.Types[types.TUINTPTR]
  2095  		idx = s.conv(nil, idx, idx.Type, t)
  2096  
  2097  		// The ending condition for the current block decides whether we'll use
  2098  		// the jump table at all.
  2099  		// We check that min <= idx <= max and jump around the jump table
  2100  		// if that test fails.
  2101  		// We implement min <= idx <= max with 0 <= idx-min <= max-min, because
  2102  		// we'll need idx-min anyway as the control value for the jump table.
  2103  		var min, max uint64
  2104  		if unsigned {
  2105  			min, _ = constant.Uint64Val(n.Cases[0])
  2106  			max, _ = constant.Uint64Val(n.Cases[len(n.Cases)-1])
  2107  		} else {
  2108  			mn, _ := constant.Int64Val(n.Cases[0])
  2109  			mx, _ := constant.Int64Val(n.Cases[len(n.Cases)-1])
  2110  			min = uint64(mn)
  2111  			max = uint64(mx)
  2112  		}
  2113  		// Compare idx-min with max-min, to see if we can use the jump table.
  2114  		idx = s.newValue2(s.ssaOp(ir.OSUB, t), t, idx, s.uintptrConstant(min))
  2115  		width := s.uintptrConstant(max - min)
  2116  		cmp := s.newValue2(s.ssaOp(ir.OLE, t), types.Types[types.TBOOL], idx, width)
  2117  		b := s.endBlock()
  2118  		b.Kind = ssa.BlockIf
  2119  		b.SetControl(cmp)
  2120  		b.AddEdgeTo(jt)             // in range - use jump table
  2121  		b.AddEdgeTo(bEnd)           // out of range - no case in the jump table will trigger
  2122  		b.Likely = ssa.BranchLikely // TODO: assumes missing the table entirely is unlikely. True?
  2123  
  2124  		// Build jump table block.
  2125  		s.startBlock(jt)
  2126  		jt.Pos = n.Pos()
  2127  		if base.Flag.Cfg.SpectreIndex {
  2128  			idx = s.newValue2(ssa.OpSpectreSliceIndex, t, idx, width)
  2129  		}
  2130  		jt.SetControl(idx)
  2131  
  2132  		// Figure out where we should go for each index in the table.
  2133  		table := make([]*ssa.Block, max-min+1)
  2134  		for i := range table {
  2135  			table[i] = bEnd // default target
  2136  		}
  2137  		for i := range n.Targets {
  2138  			c := n.Cases[i]
  2139  			lab := s.label(n.Targets[i])
  2140  			if lab.target == nil {
  2141  				lab.target = s.f.NewBlock(ssa.BlockPlain)
  2142  			}
  2143  			var val uint64
  2144  			if unsigned {
  2145  				val, _ = constant.Uint64Val(c)
  2146  			} else {
  2147  				vl, _ := constant.Int64Val(c)
  2148  				val = uint64(vl)
  2149  			}
  2150  			// Overwrite the default target.
  2151  			table[val-min] = lab.target
  2152  		}
  2153  		for _, t := range table {
  2154  			jt.AddEdgeTo(t)
  2155  		}
  2156  		s.endBlock()
  2157  
  2158  		s.startBlock(bEnd)
  2159  
  2160  	case ir.OINTERFACESWITCH:
  2161  		n := n.(*ir.InterfaceSwitchStmt)
  2162  		typs := s.f.Config.Types
  2163  
  2164  		t := s.expr(n.RuntimeType)
  2165  		h := s.expr(n.Hash)
  2166  		d := s.newValue1A(ssa.OpAddr, typs.BytePtr, n.Descriptor, s.sb)
  2167  
  2168  		// Check the cache first.
  2169  		var merge *ssa.Block
  2170  		if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Family) {
  2171  			// Note: we can only use the cache if we have the right atomic load instruction.
  2172  			// Double-check that here.
  2173  			if intrinsics.lookup(Arch.LinkArch.Arch, "internal/runtime/atomic", "Loadp") == nil {
  2174  				s.Fatalf("atomic load not available")
  2175  			}
  2176  			merge = s.f.NewBlock(ssa.BlockPlain)
  2177  			cacheHit := s.f.NewBlock(ssa.BlockPlain)
  2178  			cacheMiss := s.f.NewBlock(ssa.BlockPlain)
  2179  			loopHead := s.f.NewBlock(ssa.BlockPlain)
  2180  			loopBody := s.f.NewBlock(ssa.BlockPlain)
  2181  
  2182  			// Pick right size ops.
  2183  			var mul, and, add, zext ssa.Op
  2184  			if s.config.PtrSize == 4 {
  2185  				mul = ssa.OpMul32
  2186  				and = ssa.OpAnd32
  2187  				add = ssa.OpAdd32
  2188  				zext = ssa.OpCopy
  2189  			} else {
  2190  				mul = ssa.OpMul64
  2191  				and = ssa.OpAnd64
  2192  				add = ssa.OpAdd64
  2193  				zext = ssa.OpZeroExt32to64
  2194  			}
  2195  
  2196  			// Load cache pointer out of descriptor, with an atomic load so
  2197  			// we ensure that we see a fully written cache.
  2198  			atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  2199  			cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  2200  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  2201  
  2202  			// Initialize hash variable.
  2203  			s.vars[hashVar] = s.newValue1(zext, typs.Uintptr, h)
  2204  
  2205  			// Load mask from cache.
  2206  			mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  2207  			// Jump to loop head.
  2208  			b := s.endBlock()
  2209  			b.AddEdgeTo(loopHead)
  2210  
  2211  			// At loop head, get pointer to the cache entry.
  2212  			//   e := &cache.Entries[hash&mask]
  2213  			s.startBlock(loopHead)
  2214  			entries := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, s.uintptrConstant(uint64(s.config.PtrSize)))
  2215  			idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  2216  			idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(3*s.config.PtrSize)))
  2217  			e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, entries, idx)
  2218  			//   hash++
  2219  			s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  2220  
  2221  			// Look for a cache hit.
  2222  			//   if e.Typ == t { goto hit }
  2223  			eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  2224  			cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, t, eTyp)
  2225  			b = s.endBlock()
  2226  			b.Kind = ssa.BlockIf
  2227  			b.SetControl(cmp1)
  2228  			b.AddEdgeTo(cacheHit)
  2229  			b.AddEdgeTo(loopBody)
  2230  
  2231  			// Look for an empty entry, the tombstone for this hash table.
  2232  			//   if e.Typ == nil { goto miss }
  2233  			s.startBlock(loopBody)
  2234  			cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  2235  			b = s.endBlock()
  2236  			b.Kind = ssa.BlockIf
  2237  			b.SetControl(cmp2)
  2238  			b.AddEdgeTo(cacheMiss)
  2239  			b.AddEdgeTo(loopHead)
  2240  
  2241  			// On a hit, load the data fields of the cache entry.
  2242  			//   Case = e.Case
  2243  			//   Itab = e.Itab
  2244  			s.startBlock(cacheHit)
  2245  			eCase := s.newValue2(ssa.OpLoad, typs.Int, s.newValue1I(ssa.OpOffPtr, typs.IntPtr, s.config.PtrSize, e), s.mem())
  2246  			eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, 2*s.config.PtrSize, e), s.mem())
  2247  			s.assign(n.Case, eCase, false, 0)
  2248  			s.assign(n.Itab, eItab, false, 0)
  2249  			b = s.endBlock()
  2250  			b.AddEdgeTo(merge)
  2251  
  2252  			// On a miss, call into the runtime to get the answer.
  2253  			s.startBlock(cacheMiss)
  2254  		}
  2255  
  2256  		r := s.rtcall(ir.Syms.InterfaceSwitch, true, []*types.Type{typs.Int, typs.BytePtr}, d, t)
  2257  		s.assign(n.Case, r[0], false, 0)
  2258  		s.assign(n.Itab, r[1], false, 0)
  2259  
  2260  		if merge != nil {
  2261  			// Cache hits merge in here.
  2262  			b := s.endBlock()
  2263  			b.Kind = ssa.BlockPlain
  2264  			b.AddEdgeTo(merge)
  2265  			s.startBlock(merge)
  2266  		}
  2267  
  2268  	case ir.OCHECKNIL:
  2269  		n := n.(*ir.UnaryExpr)
  2270  		p := s.expr(n.X)
  2271  		_ = s.nilCheck(p)
  2272  		// TODO: check that throwing away the nilcheck result is ok.
  2273  
  2274  	case ir.OINLMARK:
  2275  		n := n.(*ir.InlineMarkStmt)
  2276  		s.newValue1I(ssa.OpInlMark, types.TypeVoid, n.Index, s.mem())
  2277  
  2278  	default:
  2279  		s.Fatalf("unhandled stmt %v", n.Op())
  2280  	}
  2281  }
  2282  
  2283  // If true, share as many open-coded defer exits as possible (with the downside of
  2284  // worse line-number information)
  2285  const shareDeferExits = false
  2286  
  2287  // exit processes any code that needs to be generated just before returning.
  2288  // It returns a BlockRet block that ends the control flow. Its control value
  2289  // will be set to the final memory state.
  2290  func (s *state) exit() *ssa.Block {
  2291  	if s.hasdefer {
  2292  		if s.hasOpenDefers {
  2293  			if shareDeferExits && s.lastDeferExit != nil && len(s.openDefers) == s.lastDeferCount {
  2294  				if s.curBlock.Kind != ssa.BlockPlain {
  2295  					panic("Block for an exit should be BlockPlain")
  2296  				}
  2297  				s.curBlock.AddEdgeTo(s.lastDeferExit)
  2298  				s.endBlock()
  2299  				return s.lastDeferFinalBlock
  2300  			}
  2301  			s.openDeferExit()
  2302  		} else {
  2303  			// Shared deferreturn is assigned the "last" position in the function.
  2304  			// The linker picks the first deferreturn call it sees, so this is
  2305  			// the only sensible "shared" place.
  2306  			// To not-share deferreturn, the protocol would need to be changed
  2307  			// so that the call to deferproc-etc would receive the PC offset from
  2308  			// the return PC, and the runtime would need to use that instead of
  2309  			// the deferreturn retrieved from the pcln information.
  2310  			// opendefers would remain a problem, however.
  2311  			s.pushLine(s.curfn.Endlineno)
  2312  			s.rtcall(ir.Syms.Deferreturn, true, nil)
  2313  			s.popLine()
  2314  		}
  2315  	}
  2316  
  2317  	// Do actual return.
  2318  	// These currently turn into self-copies (in many cases).
  2319  	resultFields := s.curfn.Type().Results()
  2320  	results := make([]*ssa.Value, len(resultFields)+1, len(resultFields)+1)
  2321  	// Store SSAable and heap-escaped PPARAMOUT variables back to stack locations.
  2322  	for i, f := range resultFields {
  2323  		n := f.Nname.(*ir.Name)
  2324  		if s.canSSA(n) { // result is in some SSA variable
  2325  			if !n.IsOutputParamInRegisters() && n.Type().HasPointers() {
  2326  				// We are about to store to the result slot.
  2327  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2328  			}
  2329  			results[i] = s.variable(n, n.Type())
  2330  		} else if !n.OnStack() { // result is actually heap allocated
  2331  			// We are about to copy the in-heap result to the result slot.
  2332  			if n.Type().HasPointers() {
  2333  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2334  			}
  2335  			ha := s.expr(n.Heapaddr)
  2336  			s.instrumentFields(n.Type(), ha, instrumentRead)
  2337  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), ha, s.mem())
  2338  		} else { // result is not SSA-able; not escaped, so not on heap, but too large for SSA.
  2339  			// Before register ABI this ought to be a self-move, home=dest,
  2340  			// With register ABI, it's still a self-move if parameter is on stack (i.e., too big or overflowed)
  2341  			// No VarDef, as the result slot is already holding live value.
  2342  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), s.addr(n), s.mem())
  2343  		}
  2344  	}
  2345  
  2346  	// In -race mode, we need to call racefuncexit.
  2347  	// Note: This has to happen after we load any heap-allocated results,
  2348  	// otherwise races will be attributed to the caller instead.
  2349  	if s.instrumentEnterExit {
  2350  		s.rtcall(ir.Syms.Racefuncexit, true, nil)
  2351  	}
  2352  
  2353  	results[len(results)-1] = s.mem()
  2354  	m := s.newValue0(ssa.OpMakeResult, s.f.OwnAux.LateExpansionResultType())
  2355  	m.AddArgs(results...)
  2356  
  2357  	b := s.endBlock()
  2358  	b.Kind = ssa.BlockRet
  2359  	b.SetControl(m)
  2360  	if s.hasdefer && s.hasOpenDefers {
  2361  		s.lastDeferFinalBlock = b
  2362  	}
  2363  	return b
  2364  }
  2365  
  2366  type opAndType struct {
  2367  	op    ir.Op
  2368  	etype types.Kind
  2369  }
  2370  
  2371  var opToSSA = map[opAndType]ssa.Op{
  2372  	{ir.OADD, types.TINT8}:    ssa.OpAdd8,
  2373  	{ir.OADD, types.TUINT8}:   ssa.OpAdd8,
  2374  	{ir.OADD, types.TINT16}:   ssa.OpAdd16,
  2375  	{ir.OADD, types.TUINT16}:  ssa.OpAdd16,
  2376  	{ir.OADD, types.TINT32}:   ssa.OpAdd32,
  2377  	{ir.OADD, types.TUINT32}:  ssa.OpAdd32,
  2378  	{ir.OADD, types.TINT64}:   ssa.OpAdd64,
  2379  	{ir.OADD, types.TUINT64}:  ssa.OpAdd64,
  2380  	{ir.OADD, types.TFLOAT32}: ssa.OpAdd32F,
  2381  	{ir.OADD, types.TFLOAT64}: ssa.OpAdd64F,
  2382  
  2383  	{ir.OSUB, types.TINT8}:    ssa.OpSub8,
  2384  	{ir.OSUB, types.TUINT8}:   ssa.OpSub8,
  2385  	{ir.OSUB, types.TINT16}:   ssa.OpSub16,
  2386  	{ir.OSUB, types.TUINT16}:  ssa.OpSub16,
  2387  	{ir.OSUB, types.TINT32}:   ssa.OpSub32,
  2388  	{ir.OSUB, types.TUINT32}:  ssa.OpSub32,
  2389  	{ir.OSUB, types.TINT64}:   ssa.OpSub64,
  2390  	{ir.OSUB, types.TUINT64}:  ssa.OpSub64,
  2391  	{ir.OSUB, types.TFLOAT32}: ssa.OpSub32F,
  2392  	{ir.OSUB, types.TFLOAT64}: ssa.OpSub64F,
  2393  
  2394  	{ir.ONOT, types.TBOOL}: ssa.OpNot,
  2395  
  2396  	{ir.ONEG, types.TINT8}:    ssa.OpNeg8,
  2397  	{ir.ONEG, types.TUINT8}:   ssa.OpNeg8,
  2398  	{ir.ONEG, types.TINT16}:   ssa.OpNeg16,
  2399  	{ir.ONEG, types.TUINT16}:  ssa.OpNeg16,
  2400  	{ir.ONEG, types.TINT32}:   ssa.OpNeg32,
  2401  	{ir.ONEG, types.TUINT32}:  ssa.OpNeg32,
  2402  	{ir.ONEG, types.TINT64}:   ssa.OpNeg64,
  2403  	{ir.ONEG, types.TUINT64}:  ssa.OpNeg64,
  2404  	{ir.ONEG, types.TFLOAT32}: ssa.OpNeg32F,
  2405  	{ir.ONEG, types.TFLOAT64}: ssa.OpNeg64F,
  2406  
  2407  	{ir.OBITNOT, types.TINT8}:   ssa.OpCom8,
  2408  	{ir.OBITNOT, types.TUINT8}:  ssa.OpCom8,
  2409  	{ir.OBITNOT, types.TINT16}:  ssa.OpCom16,
  2410  	{ir.OBITNOT, types.TUINT16}: ssa.OpCom16,
  2411  	{ir.OBITNOT, types.TINT32}:  ssa.OpCom32,
  2412  	{ir.OBITNOT, types.TUINT32}: ssa.OpCom32,
  2413  	{ir.OBITNOT, types.TINT64}:  ssa.OpCom64,
  2414  	{ir.OBITNOT, types.TUINT64}: ssa.OpCom64,
  2415  
  2416  	{ir.OIMAG, types.TCOMPLEX64}:  ssa.OpComplexImag,
  2417  	{ir.OIMAG, types.TCOMPLEX128}: ssa.OpComplexImag,
  2418  	{ir.OREAL, types.TCOMPLEX64}:  ssa.OpComplexReal,
  2419  	{ir.OREAL, types.TCOMPLEX128}: ssa.OpComplexReal,
  2420  
  2421  	{ir.OMUL, types.TINT8}:    ssa.OpMul8,
  2422  	{ir.OMUL, types.TUINT8}:   ssa.OpMul8,
  2423  	{ir.OMUL, types.TINT16}:   ssa.OpMul16,
  2424  	{ir.OMUL, types.TUINT16}:  ssa.OpMul16,
  2425  	{ir.OMUL, types.TINT32}:   ssa.OpMul32,
  2426  	{ir.OMUL, types.TUINT32}:  ssa.OpMul32,
  2427  	{ir.OMUL, types.TINT64}:   ssa.OpMul64,
  2428  	{ir.OMUL, types.TUINT64}:  ssa.OpMul64,
  2429  	{ir.OMUL, types.TFLOAT32}: ssa.OpMul32F,
  2430  	{ir.OMUL, types.TFLOAT64}: ssa.OpMul64F,
  2431  
  2432  	{ir.ODIV, types.TFLOAT32}: ssa.OpDiv32F,
  2433  	{ir.ODIV, types.TFLOAT64}: ssa.OpDiv64F,
  2434  
  2435  	{ir.ODIV, types.TINT8}:   ssa.OpDiv8,
  2436  	{ir.ODIV, types.TUINT8}:  ssa.OpDiv8u,
  2437  	{ir.ODIV, types.TINT16}:  ssa.OpDiv16,
  2438  	{ir.ODIV, types.TUINT16}: ssa.OpDiv16u,
  2439  	{ir.ODIV, types.TINT32}:  ssa.OpDiv32,
  2440  	{ir.ODIV, types.TUINT32}: ssa.OpDiv32u,
  2441  	{ir.ODIV, types.TINT64}:  ssa.OpDiv64,
  2442  	{ir.ODIV, types.TUINT64}: ssa.OpDiv64u,
  2443  
  2444  	{ir.OMOD, types.TINT8}:   ssa.OpMod8,
  2445  	{ir.OMOD, types.TUINT8}:  ssa.OpMod8u,
  2446  	{ir.OMOD, types.TINT16}:  ssa.OpMod16,
  2447  	{ir.OMOD, types.TUINT16}: ssa.OpMod16u,
  2448  	{ir.OMOD, types.TINT32}:  ssa.OpMod32,
  2449  	{ir.OMOD, types.TUINT32}: ssa.OpMod32u,
  2450  	{ir.OMOD, types.TINT64}:  ssa.OpMod64,
  2451  	{ir.OMOD, types.TUINT64}: ssa.OpMod64u,
  2452  
  2453  	{ir.OAND, types.TINT8}:   ssa.OpAnd8,
  2454  	{ir.OAND, types.TUINT8}:  ssa.OpAnd8,
  2455  	{ir.OAND, types.TINT16}:  ssa.OpAnd16,
  2456  	{ir.OAND, types.TUINT16}: ssa.OpAnd16,
  2457  	{ir.OAND, types.TINT32}:  ssa.OpAnd32,
  2458  	{ir.OAND, types.TUINT32}: ssa.OpAnd32,
  2459  	{ir.OAND, types.TINT64}:  ssa.OpAnd64,
  2460  	{ir.OAND, types.TUINT64}: ssa.OpAnd64,
  2461  
  2462  	{ir.OOR, types.TINT8}:   ssa.OpOr8,
  2463  	{ir.OOR, types.TUINT8}:  ssa.OpOr8,
  2464  	{ir.OOR, types.TINT16}:  ssa.OpOr16,
  2465  	{ir.OOR, types.TUINT16}: ssa.OpOr16,
  2466  	{ir.OOR, types.TINT32}:  ssa.OpOr32,
  2467  	{ir.OOR, types.TUINT32}: ssa.OpOr32,
  2468  	{ir.OOR, types.TINT64}:  ssa.OpOr64,
  2469  	{ir.OOR, types.TUINT64}: ssa.OpOr64,
  2470  
  2471  	{ir.OXOR, types.TINT8}:   ssa.OpXor8,
  2472  	{ir.OXOR, types.TUINT8}:  ssa.OpXor8,
  2473  	{ir.OXOR, types.TINT16}:  ssa.OpXor16,
  2474  	{ir.OXOR, types.TUINT16}: ssa.OpXor16,
  2475  	{ir.OXOR, types.TINT32}:  ssa.OpXor32,
  2476  	{ir.OXOR, types.TUINT32}: ssa.OpXor32,
  2477  	{ir.OXOR, types.TINT64}:  ssa.OpXor64,
  2478  	{ir.OXOR, types.TUINT64}: ssa.OpXor64,
  2479  
  2480  	{ir.OEQ, types.TBOOL}:      ssa.OpEqB,
  2481  	{ir.OEQ, types.TINT8}:      ssa.OpEq8,
  2482  	{ir.OEQ, types.TUINT8}:     ssa.OpEq8,
  2483  	{ir.OEQ, types.TINT16}:     ssa.OpEq16,
  2484  	{ir.OEQ, types.TUINT16}:    ssa.OpEq16,
  2485  	{ir.OEQ, types.TINT32}:     ssa.OpEq32,
  2486  	{ir.OEQ, types.TUINT32}:    ssa.OpEq32,
  2487  	{ir.OEQ, types.TINT64}:     ssa.OpEq64,
  2488  	{ir.OEQ, types.TUINT64}:    ssa.OpEq64,
  2489  	{ir.OEQ, types.TINTER}:     ssa.OpEqInter,
  2490  	{ir.OEQ, types.TSLICE}:     ssa.OpEqSlice,
  2491  	{ir.OEQ, types.TFUNC}:      ssa.OpEqPtr,
  2492  	{ir.OEQ, types.TMAP}:       ssa.OpEqPtr,
  2493  	{ir.OEQ, types.TCHAN}:      ssa.OpEqPtr,
  2494  	{ir.OEQ, types.TPTR}:       ssa.OpEqPtr,
  2495  	{ir.OEQ, types.TUINTPTR}:   ssa.OpEqPtr,
  2496  	{ir.OEQ, types.TUNSAFEPTR}: ssa.OpEqPtr,
  2497  	{ir.OEQ, types.TFLOAT64}:   ssa.OpEq64F,
  2498  	{ir.OEQ, types.TFLOAT32}:   ssa.OpEq32F,
  2499  
  2500  	{ir.ONE, types.TBOOL}:      ssa.OpNeqB,
  2501  	{ir.ONE, types.TINT8}:      ssa.OpNeq8,
  2502  	{ir.ONE, types.TUINT8}:     ssa.OpNeq8,
  2503  	{ir.ONE, types.TINT16}:     ssa.OpNeq16,
  2504  	{ir.ONE, types.TUINT16}:    ssa.OpNeq16,
  2505  	{ir.ONE, types.TINT32}:     ssa.OpNeq32,
  2506  	{ir.ONE, types.TUINT32}:    ssa.OpNeq32,
  2507  	{ir.ONE, types.TINT64}:     ssa.OpNeq64,
  2508  	{ir.ONE, types.TUINT64}:    ssa.OpNeq64,
  2509  	{ir.ONE, types.TINTER}:     ssa.OpNeqInter,
  2510  	{ir.ONE, types.TSLICE}:     ssa.OpNeqSlice,
  2511  	{ir.ONE, types.TFUNC}:      ssa.OpNeqPtr,
  2512  	{ir.ONE, types.TMAP}:       ssa.OpNeqPtr,
  2513  	{ir.ONE, types.TCHAN}:      ssa.OpNeqPtr,
  2514  	{ir.ONE, types.TPTR}:       ssa.OpNeqPtr,
  2515  	{ir.ONE, types.TUINTPTR}:   ssa.OpNeqPtr,
  2516  	{ir.ONE, types.TUNSAFEPTR}: ssa.OpNeqPtr,
  2517  	{ir.ONE, types.TFLOAT64}:   ssa.OpNeq64F,
  2518  	{ir.ONE, types.TFLOAT32}:   ssa.OpNeq32F,
  2519  
  2520  	{ir.OLT, types.TINT8}:    ssa.OpLess8,
  2521  	{ir.OLT, types.TUINT8}:   ssa.OpLess8U,
  2522  	{ir.OLT, types.TINT16}:   ssa.OpLess16,
  2523  	{ir.OLT, types.TUINT16}:  ssa.OpLess16U,
  2524  	{ir.OLT, types.TINT32}:   ssa.OpLess32,
  2525  	{ir.OLT, types.TUINT32}:  ssa.OpLess32U,
  2526  	{ir.OLT, types.TINT64}:   ssa.OpLess64,
  2527  	{ir.OLT, types.TUINT64}:  ssa.OpLess64U,
  2528  	{ir.OLT, types.TFLOAT64}: ssa.OpLess64F,
  2529  	{ir.OLT, types.TFLOAT32}: ssa.OpLess32F,
  2530  
  2531  	{ir.OLE, types.TINT8}:    ssa.OpLeq8,
  2532  	{ir.OLE, types.TUINT8}:   ssa.OpLeq8U,
  2533  	{ir.OLE, types.TINT16}:   ssa.OpLeq16,
  2534  	{ir.OLE, types.TUINT16}:  ssa.OpLeq16U,
  2535  	{ir.OLE, types.TINT32}:   ssa.OpLeq32,
  2536  	{ir.OLE, types.TUINT32}:  ssa.OpLeq32U,
  2537  	{ir.OLE, types.TINT64}:   ssa.OpLeq64,
  2538  	{ir.OLE, types.TUINT64}:  ssa.OpLeq64U,
  2539  	{ir.OLE, types.TFLOAT64}: ssa.OpLeq64F,
  2540  	{ir.OLE, types.TFLOAT32}: ssa.OpLeq32F,
  2541  }
  2542  
  2543  func (s *state) concreteEtype(t *types.Type) types.Kind {
  2544  	e := t.Kind()
  2545  	switch e {
  2546  	default:
  2547  		return e
  2548  	case types.TINT:
  2549  		if s.config.PtrSize == 8 {
  2550  			return types.TINT64
  2551  		}
  2552  		return types.TINT32
  2553  	case types.TUINT:
  2554  		if s.config.PtrSize == 8 {
  2555  			return types.TUINT64
  2556  		}
  2557  		return types.TUINT32
  2558  	case types.TUINTPTR:
  2559  		if s.config.PtrSize == 8 {
  2560  			return types.TUINT64
  2561  		}
  2562  		return types.TUINT32
  2563  	}
  2564  }
  2565  
  2566  func (s *state) ssaOp(op ir.Op, t *types.Type) ssa.Op {
  2567  	etype := s.concreteEtype(t)
  2568  	x, ok := opToSSA[opAndType{op, etype}]
  2569  	if !ok {
  2570  		s.Fatalf("unhandled binary op %v %s", op, etype)
  2571  	}
  2572  	return x
  2573  }
  2574  
  2575  type opAndTwoTypes struct {
  2576  	op     ir.Op
  2577  	etype1 types.Kind
  2578  	etype2 types.Kind
  2579  }
  2580  
  2581  type twoTypes struct {
  2582  	etype1 types.Kind
  2583  	etype2 types.Kind
  2584  }
  2585  
  2586  type twoOpsAndType struct {
  2587  	op1              ssa.Op
  2588  	op2              ssa.Op
  2589  	intermediateType types.Kind
  2590  }
  2591  
  2592  var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2593  
  2594  	{types.TINT8, types.TFLOAT32}:  {ssa.OpSignExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2595  	{types.TINT16, types.TFLOAT32}: {ssa.OpSignExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2596  	{types.TINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32to32F, types.TINT32},
  2597  	{types.TINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64to32F, types.TINT64},
  2598  
  2599  	{types.TINT8, types.TFLOAT64}:  {ssa.OpSignExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2600  	{types.TINT16, types.TFLOAT64}: {ssa.OpSignExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2601  	{types.TINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32to64F, types.TINT32},
  2602  	{types.TINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64to64F, types.TINT64},
  2603  
  2604  	{types.TFLOAT32, types.TINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2605  	{types.TFLOAT32, types.TINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2606  	{types.TFLOAT32, types.TINT32}: {ssa.OpCvt32Fto32, ssa.OpCopy, types.TINT32},
  2607  	{types.TFLOAT32, types.TINT64}: {ssa.OpCvt32Fto64, ssa.OpCopy, types.TINT64},
  2608  
  2609  	{types.TFLOAT64, types.TINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2610  	{types.TFLOAT64, types.TINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2611  	{types.TFLOAT64, types.TINT32}: {ssa.OpCvt64Fto32, ssa.OpCopy, types.TINT32},
  2612  	{types.TFLOAT64, types.TINT64}: {ssa.OpCvt64Fto64, ssa.OpCopy, types.TINT64},
  2613  	// unsigned
  2614  	{types.TUINT8, types.TFLOAT32}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2615  	{types.TUINT16, types.TFLOAT32}: {ssa.OpZeroExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2616  	{types.TUINT32, types.TFLOAT32}: {ssa.OpZeroExt32to64, ssa.OpCvt64to32F, types.TINT64}, // go wide to dodge unsigned
  2617  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto32F, branchy code expansion instead
  2618  
  2619  	{types.TUINT8, types.TFLOAT64}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2620  	{types.TUINT16, types.TFLOAT64}: {ssa.OpZeroExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2621  	{types.TUINT32, types.TFLOAT64}: {ssa.OpZeroExt32to64, ssa.OpCvt64to64F, types.TINT64}, // go wide to dodge unsigned
  2622  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto64F, branchy code expansion instead
  2623  
  2624  	{types.TFLOAT32, types.TUINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2625  	{types.TFLOAT32, types.TUINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2626  	{types.TFLOAT32, types.TUINT32}: {ssa.OpCvt32Fto64, ssa.OpTrunc64to32, types.TINT64}, // go wide to dodge unsigned
  2627  	{types.TFLOAT32, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64},          // Cvt32Fto64U, branchy code expansion instead
  2628  
  2629  	{types.TFLOAT64, types.TUINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2630  	{types.TFLOAT64, types.TUINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2631  	{types.TFLOAT64, types.TUINT32}: {ssa.OpCvt64Fto64, ssa.OpTrunc64to32, types.TINT64}, // go wide to dodge unsigned
  2632  	{types.TFLOAT64, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64},          // Cvt64Fto64U, branchy code expansion instead
  2633  
  2634  	// float
  2635  	{types.TFLOAT64, types.TFLOAT32}: {ssa.OpCvt64Fto32F, ssa.OpCopy, types.TFLOAT32},
  2636  	{types.TFLOAT64, types.TFLOAT64}: {ssa.OpRound64F, ssa.OpCopy, types.TFLOAT64},
  2637  	{types.TFLOAT32, types.TFLOAT32}: {ssa.OpRound32F, ssa.OpCopy, types.TFLOAT32},
  2638  	{types.TFLOAT32, types.TFLOAT64}: {ssa.OpCvt32Fto64F, ssa.OpCopy, types.TFLOAT64},
  2639  }
  2640  
  2641  // this map is used only for 32-bit arch, and only includes the difference
  2642  // on 32-bit arch, don't use int64<->float conversion for uint32
  2643  var fpConvOpToSSA32 = map[twoTypes]twoOpsAndType{
  2644  	{types.TUINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32Uto32F, types.TUINT32},
  2645  	{types.TUINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32Uto64F, types.TUINT32},
  2646  	{types.TFLOAT32, types.TUINT32}: {ssa.OpCvt32Fto32U, ssa.OpCopy, types.TUINT32},
  2647  	{types.TFLOAT64, types.TUINT32}: {ssa.OpCvt64Fto32U, ssa.OpCopy, types.TUINT32},
  2648  }
  2649  
  2650  // uint64<->float conversions, only on machines that have instructions for that
  2651  var uint64fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2652  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64Uto32F, types.TUINT64},
  2653  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64Uto64F, types.TUINT64},
  2654  	{types.TFLOAT32, types.TUINT64}: {ssa.OpCvt32Fto64U, ssa.OpCopy, types.TUINT64},
  2655  	{types.TFLOAT64, types.TUINT64}: {ssa.OpCvt64Fto64U, ssa.OpCopy, types.TUINT64},
  2656  }
  2657  
  2658  var shiftOpToSSA = map[opAndTwoTypes]ssa.Op{
  2659  	{ir.OLSH, types.TINT8, types.TUINT8}:   ssa.OpLsh8x8,
  2660  	{ir.OLSH, types.TUINT8, types.TUINT8}:  ssa.OpLsh8x8,
  2661  	{ir.OLSH, types.TINT8, types.TUINT16}:  ssa.OpLsh8x16,
  2662  	{ir.OLSH, types.TUINT8, types.TUINT16}: ssa.OpLsh8x16,
  2663  	{ir.OLSH, types.TINT8, types.TUINT32}:  ssa.OpLsh8x32,
  2664  	{ir.OLSH, types.TUINT8, types.TUINT32}: ssa.OpLsh8x32,
  2665  	{ir.OLSH, types.TINT8, types.TUINT64}:  ssa.OpLsh8x64,
  2666  	{ir.OLSH, types.TUINT8, types.TUINT64}: ssa.OpLsh8x64,
  2667  
  2668  	{ir.OLSH, types.TINT16, types.TUINT8}:   ssa.OpLsh16x8,
  2669  	{ir.OLSH, types.TUINT16, types.TUINT8}:  ssa.OpLsh16x8,
  2670  	{ir.OLSH, types.TINT16, types.TUINT16}:  ssa.OpLsh16x16,
  2671  	{ir.OLSH, types.TUINT16, types.TUINT16}: ssa.OpLsh16x16,
  2672  	{ir.OLSH, types.TINT16, types.TUINT32}:  ssa.OpLsh16x32,
  2673  	{ir.OLSH, types.TUINT16, types.TUINT32}: ssa.OpLsh16x32,
  2674  	{ir.OLSH, types.TINT16, types.TUINT64}:  ssa.OpLsh16x64,
  2675  	{ir.OLSH, types.TUINT16, types.TUINT64}: ssa.OpLsh16x64,
  2676  
  2677  	{ir.OLSH, types.TINT32, types.TUINT8}:   ssa.OpLsh32x8,
  2678  	{ir.OLSH, types.TUINT32, types.TUINT8}:  ssa.OpLsh32x8,
  2679  	{ir.OLSH, types.TINT32, types.TUINT16}:  ssa.OpLsh32x16,
  2680  	{ir.OLSH, types.TUINT32, types.TUINT16}: ssa.OpLsh32x16,
  2681  	{ir.OLSH, types.TINT32, types.TUINT32}:  ssa.OpLsh32x32,
  2682  	{ir.OLSH, types.TUINT32, types.TUINT32}: ssa.OpLsh32x32,
  2683  	{ir.OLSH, types.TINT32, types.TUINT64}:  ssa.OpLsh32x64,
  2684  	{ir.OLSH, types.TUINT32, types.TUINT64}: ssa.OpLsh32x64,
  2685  
  2686  	{ir.OLSH, types.TINT64, types.TUINT8}:   ssa.OpLsh64x8,
  2687  	{ir.OLSH, types.TUINT64, types.TUINT8}:  ssa.OpLsh64x8,
  2688  	{ir.OLSH, types.TINT64, types.TUINT16}:  ssa.OpLsh64x16,
  2689  	{ir.OLSH, types.TUINT64, types.TUINT16}: ssa.OpLsh64x16,
  2690  	{ir.OLSH, types.TINT64, types.TUINT32}:  ssa.OpLsh64x32,
  2691  	{ir.OLSH, types.TUINT64, types.TUINT32}: ssa.OpLsh64x32,
  2692  	{ir.OLSH, types.TINT64, types.TUINT64}:  ssa.OpLsh64x64,
  2693  	{ir.OLSH, types.TUINT64, types.TUINT64}: ssa.OpLsh64x64,
  2694  
  2695  	{ir.ORSH, types.TINT8, types.TUINT8}:   ssa.OpRsh8x8,
  2696  	{ir.ORSH, types.TUINT8, types.TUINT8}:  ssa.OpRsh8Ux8,
  2697  	{ir.ORSH, types.TINT8, types.TUINT16}:  ssa.OpRsh8x16,
  2698  	{ir.ORSH, types.TUINT8, types.TUINT16}: ssa.OpRsh8Ux16,
  2699  	{ir.ORSH, types.TINT8, types.TUINT32}:  ssa.OpRsh8x32,
  2700  	{ir.ORSH, types.TUINT8, types.TUINT32}: ssa.OpRsh8Ux32,
  2701  	{ir.ORSH, types.TINT8, types.TUINT64}:  ssa.OpRsh8x64,
  2702  	{ir.ORSH, types.TUINT8, types.TUINT64}: ssa.OpRsh8Ux64,
  2703  
  2704  	{ir.ORSH, types.TINT16, types.TUINT8}:   ssa.OpRsh16x8,
  2705  	{ir.ORSH, types.TUINT16, types.TUINT8}:  ssa.OpRsh16Ux8,
  2706  	{ir.ORSH, types.TINT16, types.TUINT16}:  ssa.OpRsh16x16,
  2707  	{ir.ORSH, types.TUINT16, types.TUINT16}: ssa.OpRsh16Ux16,
  2708  	{ir.ORSH, types.TINT16, types.TUINT32}:  ssa.OpRsh16x32,
  2709  	{ir.ORSH, types.TUINT16, types.TUINT32}: ssa.OpRsh16Ux32,
  2710  	{ir.ORSH, types.TINT16, types.TUINT64}:  ssa.OpRsh16x64,
  2711  	{ir.ORSH, types.TUINT16, types.TUINT64}: ssa.OpRsh16Ux64,
  2712  
  2713  	{ir.ORSH, types.TINT32, types.TUINT8}:   ssa.OpRsh32x8,
  2714  	{ir.ORSH, types.TUINT32, types.TUINT8}:  ssa.OpRsh32Ux8,
  2715  	{ir.ORSH, types.TINT32, types.TUINT16}:  ssa.OpRsh32x16,
  2716  	{ir.ORSH, types.TUINT32, types.TUINT16}: ssa.OpRsh32Ux16,
  2717  	{ir.ORSH, types.TINT32, types.TUINT32}:  ssa.OpRsh32x32,
  2718  	{ir.ORSH, types.TUINT32, types.TUINT32}: ssa.OpRsh32Ux32,
  2719  	{ir.ORSH, types.TINT32, types.TUINT64}:  ssa.OpRsh32x64,
  2720  	{ir.ORSH, types.TUINT32, types.TUINT64}: ssa.OpRsh32Ux64,
  2721  
  2722  	{ir.ORSH, types.TINT64, types.TUINT8}:   ssa.OpRsh64x8,
  2723  	{ir.ORSH, types.TUINT64, types.TUINT8}:  ssa.OpRsh64Ux8,
  2724  	{ir.ORSH, types.TINT64, types.TUINT16}:  ssa.OpRsh64x16,
  2725  	{ir.ORSH, types.TUINT64, types.TUINT16}: ssa.OpRsh64Ux16,
  2726  	{ir.ORSH, types.TINT64, types.TUINT32}:  ssa.OpRsh64x32,
  2727  	{ir.ORSH, types.TUINT64, types.TUINT32}: ssa.OpRsh64Ux32,
  2728  	{ir.ORSH, types.TINT64, types.TUINT64}:  ssa.OpRsh64x64,
  2729  	{ir.ORSH, types.TUINT64, types.TUINT64}: ssa.OpRsh64Ux64,
  2730  }
  2731  
  2732  func (s *state) ssaShiftOp(op ir.Op, t *types.Type, u *types.Type) ssa.Op {
  2733  	etype1 := s.concreteEtype(t)
  2734  	etype2 := s.concreteEtype(u)
  2735  	x, ok := shiftOpToSSA[opAndTwoTypes{op, etype1, etype2}]
  2736  	if !ok {
  2737  		s.Fatalf("unhandled shift op %v etype=%s/%s", op, etype1, etype2)
  2738  	}
  2739  	return x
  2740  }
  2741  
  2742  func (s *state) uintptrConstant(v uint64) *ssa.Value {
  2743  	if s.config.PtrSize == 4 {
  2744  		return s.newValue0I(ssa.OpConst32, types.Types[types.TUINTPTR], int64(v))
  2745  	}
  2746  	return s.newValue0I(ssa.OpConst64, types.Types[types.TUINTPTR], int64(v))
  2747  }
  2748  
  2749  func (s *state) conv(n ir.Node, v *ssa.Value, ft, tt *types.Type) *ssa.Value {
  2750  	if ft.IsBoolean() && tt.IsKind(types.TUINT8) {
  2751  		// Bool -> uint8 is generated internally when indexing into runtime.staticbyte.
  2752  		return s.newValue1(ssa.OpCvtBoolToUint8, tt, v)
  2753  	}
  2754  	if ft.IsInteger() && tt.IsInteger() {
  2755  		var op ssa.Op
  2756  		if tt.Size() == ft.Size() {
  2757  			op = ssa.OpCopy
  2758  		} else if tt.Size() < ft.Size() {
  2759  			// truncation
  2760  			switch 10*ft.Size() + tt.Size() {
  2761  			case 21:
  2762  				op = ssa.OpTrunc16to8
  2763  			case 41:
  2764  				op = ssa.OpTrunc32to8
  2765  			case 42:
  2766  				op = ssa.OpTrunc32to16
  2767  			case 81:
  2768  				op = ssa.OpTrunc64to8
  2769  			case 82:
  2770  				op = ssa.OpTrunc64to16
  2771  			case 84:
  2772  				op = ssa.OpTrunc64to32
  2773  			default:
  2774  				s.Fatalf("weird integer truncation %v -> %v", ft, tt)
  2775  			}
  2776  		} else if ft.IsSigned() {
  2777  			// sign extension
  2778  			switch 10*ft.Size() + tt.Size() {
  2779  			case 12:
  2780  				op = ssa.OpSignExt8to16
  2781  			case 14:
  2782  				op = ssa.OpSignExt8to32
  2783  			case 18:
  2784  				op = ssa.OpSignExt8to64
  2785  			case 24:
  2786  				op = ssa.OpSignExt16to32
  2787  			case 28:
  2788  				op = ssa.OpSignExt16to64
  2789  			case 48:
  2790  				op = ssa.OpSignExt32to64
  2791  			default:
  2792  				s.Fatalf("bad integer sign extension %v -> %v", ft, tt)
  2793  			}
  2794  		} else {
  2795  			// zero extension
  2796  			switch 10*ft.Size() + tt.Size() {
  2797  			case 12:
  2798  				op = ssa.OpZeroExt8to16
  2799  			case 14:
  2800  				op = ssa.OpZeroExt8to32
  2801  			case 18:
  2802  				op = ssa.OpZeroExt8to64
  2803  			case 24:
  2804  				op = ssa.OpZeroExt16to32
  2805  			case 28:
  2806  				op = ssa.OpZeroExt16to64
  2807  			case 48:
  2808  				op = ssa.OpZeroExt32to64
  2809  			default:
  2810  				s.Fatalf("weird integer sign extension %v -> %v", ft, tt)
  2811  			}
  2812  		}
  2813  		return s.newValue1(op, tt, v)
  2814  	}
  2815  
  2816  	if ft.IsComplex() && tt.IsComplex() {
  2817  		var op ssa.Op
  2818  		if ft.Size() == tt.Size() {
  2819  			switch ft.Size() {
  2820  			case 8:
  2821  				op = ssa.OpRound32F
  2822  			case 16:
  2823  				op = ssa.OpRound64F
  2824  			default:
  2825  				s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2826  			}
  2827  		} else if ft.Size() == 8 && tt.Size() == 16 {
  2828  			op = ssa.OpCvt32Fto64F
  2829  		} else if ft.Size() == 16 && tt.Size() == 8 {
  2830  			op = ssa.OpCvt64Fto32F
  2831  		} else {
  2832  			s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2833  		}
  2834  		ftp := types.FloatForComplex(ft)
  2835  		ttp := types.FloatForComplex(tt)
  2836  		return s.newValue2(ssa.OpComplexMake, tt,
  2837  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, v)),
  2838  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, v)))
  2839  	}
  2840  
  2841  	if tt.IsComplex() { // and ft is not complex
  2842  		// Needed for generics support - can't happen in normal Go code.
  2843  		et := types.FloatForComplex(tt)
  2844  		v = s.conv(n, v, ft, et)
  2845  		return s.newValue2(ssa.OpComplexMake, tt, v, s.zeroVal(et))
  2846  	}
  2847  
  2848  	if ft.IsFloat() || tt.IsFloat() {
  2849  		conv, ok := fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]
  2850  		if s.config.RegSize == 4 && Arch.LinkArch.Family != sys.MIPS && !s.softFloat {
  2851  			if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2852  				conv = conv1
  2853  			}
  2854  		}
  2855  		if Arch.LinkArch.Family == sys.ARM64 || Arch.LinkArch.Family == sys.Wasm || Arch.LinkArch.Family == sys.S390X || s.softFloat {
  2856  			if conv1, ok1 := uint64fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2857  				conv = conv1
  2858  			}
  2859  		}
  2860  
  2861  		if Arch.LinkArch.Family == sys.MIPS && !s.softFloat {
  2862  			if ft.Size() == 4 && ft.IsInteger() && !ft.IsSigned() {
  2863  				// tt is float32 or float64, and ft is also unsigned
  2864  				if tt.Size() == 4 {
  2865  					return s.uint32Tofloat32(n, v, ft, tt)
  2866  				}
  2867  				if tt.Size() == 8 {
  2868  					return s.uint32Tofloat64(n, v, ft, tt)
  2869  				}
  2870  			} else if tt.Size() == 4 && tt.IsInteger() && !tt.IsSigned() {
  2871  				// ft is float32 or float64, and tt is unsigned integer
  2872  				if ft.Size() == 4 {
  2873  					return s.float32ToUint32(n, v, ft, tt)
  2874  				}
  2875  				if ft.Size() == 8 {
  2876  					return s.float64ToUint32(n, v, ft, tt)
  2877  				}
  2878  			}
  2879  		}
  2880  
  2881  		if !ok {
  2882  			s.Fatalf("weird float conversion %v -> %v", ft, tt)
  2883  		}
  2884  		op1, op2, it := conv.op1, conv.op2, conv.intermediateType
  2885  
  2886  		if op1 != ssa.OpInvalid && op2 != ssa.OpInvalid {
  2887  			// normal case, not tripping over unsigned 64
  2888  			if op1 == ssa.OpCopy {
  2889  				if op2 == ssa.OpCopy {
  2890  					return v
  2891  				}
  2892  				return s.newValueOrSfCall1(op2, tt, v)
  2893  			}
  2894  			if op2 == ssa.OpCopy {
  2895  				return s.newValueOrSfCall1(op1, tt, v)
  2896  			}
  2897  			return s.newValueOrSfCall1(op2, tt, s.newValueOrSfCall1(op1, types.Types[it], v))
  2898  		}
  2899  		// Tricky 64-bit unsigned cases.
  2900  		if ft.IsInteger() {
  2901  			// tt is float32 or float64, and ft is also unsigned
  2902  			if tt.Size() == 4 {
  2903  				return s.uint64Tofloat32(n, v, ft, tt)
  2904  			}
  2905  			if tt.Size() == 8 {
  2906  				return s.uint64Tofloat64(n, v, ft, tt)
  2907  			}
  2908  			s.Fatalf("weird unsigned integer to float conversion %v -> %v", ft, tt)
  2909  		}
  2910  		// ft is float32 or float64, and tt is unsigned integer
  2911  		if ft.Size() == 4 {
  2912  			return s.float32ToUint64(n, v, ft, tt)
  2913  		}
  2914  		if ft.Size() == 8 {
  2915  			return s.float64ToUint64(n, v, ft, tt)
  2916  		}
  2917  		s.Fatalf("weird float to unsigned integer conversion %v -> %v", ft, tt)
  2918  		return nil
  2919  	}
  2920  
  2921  	s.Fatalf("unhandled OCONV %s -> %s", ft.Kind(), tt.Kind())
  2922  	return nil
  2923  }
  2924  
  2925  // expr converts the expression n to ssa, adds it to s and returns the ssa result.
  2926  func (s *state) expr(n ir.Node) *ssa.Value {
  2927  	return s.exprCheckPtr(n, true)
  2928  }
  2929  
  2930  func (s *state) exprCheckPtr(n ir.Node, checkPtrOK bool) *ssa.Value {
  2931  	if ir.HasUniquePos(n) {
  2932  		// ONAMEs and named OLITERALs have the line number
  2933  		// of the decl, not the use. See issue 14742.
  2934  		s.pushLine(n.Pos())
  2935  		defer s.popLine()
  2936  	}
  2937  
  2938  	s.stmtList(n.Init())
  2939  	switch n.Op() {
  2940  	case ir.OBYTES2STRTMP:
  2941  		n := n.(*ir.ConvExpr)
  2942  		slice := s.expr(n.X)
  2943  		ptr := s.newValue1(ssa.OpSlicePtr, s.f.Config.Types.BytePtr, slice)
  2944  		len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  2945  		return s.newValue2(ssa.OpStringMake, n.Type(), ptr, len)
  2946  	case ir.OSTR2BYTESTMP:
  2947  		n := n.(*ir.ConvExpr)
  2948  		str := s.expr(n.X)
  2949  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, str)
  2950  		if !n.NonNil() {
  2951  			// We need to ensure []byte("") evaluates to []byte{}, and not []byte(nil).
  2952  			//
  2953  			// TODO(mdempsky): Investigate using "len != 0" instead of "ptr != nil".
  2954  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], ptr, s.constNil(ptr.Type))
  2955  			zerobase := s.newValue1A(ssa.OpAddr, ptr.Type, ir.Syms.Zerobase, s.sb)
  2956  			ptr = s.ternary(cond, ptr, zerobase)
  2957  		}
  2958  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], str)
  2959  		return s.newValue3(ssa.OpSliceMake, n.Type(), ptr, len, len)
  2960  	case ir.OCFUNC:
  2961  		n := n.(*ir.UnaryExpr)
  2962  		aux := n.X.(*ir.Name).Linksym()
  2963  		// OCFUNC is used to build function values, which must
  2964  		// always reference ABIInternal entry points.
  2965  		if aux.ABI() != obj.ABIInternal {
  2966  			s.Fatalf("expected ABIInternal: %v", aux.ABI())
  2967  		}
  2968  		return s.entryNewValue1A(ssa.OpAddr, n.Type(), aux, s.sb)
  2969  	case ir.ONAME:
  2970  		n := n.(*ir.Name)
  2971  		if n.Class == ir.PFUNC {
  2972  			// "value" of a function is the address of the function's closure
  2973  			sym := staticdata.FuncLinksym(n)
  2974  			return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(n.Type()), sym, s.sb)
  2975  		}
  2976  		if s.canSSA(n) {
  2977  			return s.variable(n, n.Type())
  2978  		}
  2979  		return s.load(n.Type(), s.addr(n))
  2980  	case ir.OLINKSYMOFFSET:
  2981  		n := n.(*ir.LinksymOffsetExpr)
  2982  		return s.load(n.Type(), s.addr(n))
  2983  	case ir.ONIL:
  2984  		n := n.(*ir.NilExpr)
  2985  		t := n.Type()
  2986  		switch {
  2987  		case t.IsSlice():
  2988  			return s.constSlice(t)
  2989  		case t.IsInterface():
  2990  			return s.constInterface(t)
  2991  		default:
  2992  			return s.constNil(t)
  2993  		}
  2994  	case ir.OLITERAL:
  2995  		switch u := n.Val(); u.Kind() {
  2996  		case constant.Int:
  2997  			i := ir.IntVal(n.Type(), u)
  2998  			switch n.Type().Size() {
  2999  			case 1:
  3000  				return s.constInt8(n.Type(), int8(i))
  3001  			case 2:
  3002  				return s.constInt16(n.Type(), int16(i))
  3003  			case 4:
  3004  				return s.constInt32(n.Type(), int32(i))
  3005  			case 8:
  3006  				return s.constInt64(n.Type(), i)
  3007  			default:
  3008  				s.Fatalf("bad integer size %d", n.Type().Size())
  3009  				return nil
  3010  			}
  3011  		case constant.String:
  3012  			i := constant.StringVal(u)
  3013  			if i == "" {
  3014  				return s.constEmptyString(n.Type())
  3015  			}
  3016  			return s.entryNewValue0A(ssa.OpConstString, n.Type(), ssa.StringToAux(i))
  3017  		case constant.Bool:
  3018  			return s.constBool(constant.BoolVal(u))
  3019  		case constant.Float:
  3020  			f, _ := constant.Float64Val(u)
  3021  			switch n.Type().Size() {
  3022  			case 4:
  3023  				return s.constFloat32(n.Type(), f)
  3024  			case 8:
  3025  				return s.constFloat64(n.Type(), f)
  3026  			default:
  3027  				s.Fatalf("bad float size %d", n.Type().Size())
  3028  				return nil
  3029  			}
  3030  		case constant.Complex:
  3031  			re, _ := constant.Float64Val(constant.Real(u))
  3032  			im, _ := constant.Float64Val(constant.Imag(u))
  3033  			switch n.Type().Size() {
  3034  			case 8:
  3035  				pt := types.Types[types.TFLOAT32]
  3036  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  3037  					s.constFloat32(pt, re),
  3038  					s.constFloat32(pt, im))
  3039  			case 16:
  3040  				pt := types.Types[types.TFLOAT64]
  3041  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  3042  					s.constFloat64(pt, re),
  3043  					s.constFloat64(pt, im))
  3044  			default:
  3045  				s.Fatalf("bad complex size %d", n.Type().Size())
  3046  				return nil
  3047  			}
  3048  		default:
  3049  			s.Fatalf("unhandled OLITERAL %v", u.Kind())
  3050  			return nil
  3051  		}
  3052  	case ir.OCONVNOP:
  3053  		n := n.(*ir.ConvExpr)
  3054  		to := n.Type()
  3055  		from := n.X.Type()
  3056  
  3057  		// Assume everything will work out, so set up our return value.
  3058  		// Anything interesting that happens from here is a fatal.
  3059  		x := s.expr(n.X)
  3060  		if to == from {
  3061  			return x
  3062  		}
  3063  
  3064  		// Special case for not confusing GC and liveness.
  3065  		// We don't want pointers accidentally classified
  3066  		// as not-pointers or vice-versa because of copy
  3067  		// elision.
  3068  		if to.IsPtrShaped() != from.IsPtrShaped() {
  3069  			return s.newValue2(ssa.OpConvert, to, x, s.mem())
  3070  		}
  3071  
  3072  		v := s.newValue1(ssa.OpCopy, to, x) // ensure that v has the right type
  3073  
  3074  		// CONVNOP closure
  3075  		if to.Kind() == types.TFUNC && from.IsPtrShaped() {
  3076  			return v
  3077  		}
  3078  
  3079  		// named <--> unnamed type or typed <--> untyped const
  3080  		if from.Kind() == to.Kind() {
  3081  			return v
  3082  		}
  3083  
  3084  		// unsafe.Pointer <--> *T
  3085  		if to.IsUnsafePtr() && from.IsPtrShaped() || from.IsUnsafePtr() && to.IsPtrShaped() {
  3086  			if s.checkPtrEnabled && checkPtrOK && to.IsPtr() && from.IsUnsafePtr() {
  3087  				s.checkPtrAlignment(n, v, nil)
  3088  			}
  3089  			return v
  3090  		}
  3091  
  3092  		// map <--> *hmap
  3093  		var mt *types.Type
  3094  		if buildcfg.Experiment.SwissMap {
  3095  			mt = types.NewPtr(reflectdata.SwissMapType())
  3096  		} else {
  3097  			mt = types.NewPtr(reflectdata.OldMapType())
  3098  		}
  3099  		if to.Kind() == types.TMAP && from == mt {
  3100  			return v
  3101  		}
  3102  
  3103  		types.CalcSize(from)
  3104  		types.CalcSize(to)
  3105  		if from.Size() != to.Size() {
  3106  			s.Fatalf("CONVNOP width mismatch %v (%d) -> %v (%d)\n", from, from.Size(), to, to.Size())
  3107  			return nil
  3108  		}
  3109  		if etypesign(from.Kind()) != etypesign(to.Kind()) {
  3110  			s.Fatalf("CONVNOP sign mismatch %v (%s) -> %v (%s)\n", from, from.Kind(), to, to.Kind())
  3111  			return nil
  3112  		}
  3113  
  3114  		if base.Flag.Cfg.Instrumenting {
  3115  			// These appear to be fine, but they fail the
  3116  			// integer constraint below, so okay them here.
  3117  			// Sample non-integer conversion: map[string]string -> *uint8
  3118  			return v
  3119  		}
  3120  
  3121  		if etypesign(from.Kind()) == 0 {
  3122  			s.Fatalf("CONVNOP unrecognized non-integer %v -> %v\n", from, to)
  3123  			return nil
  3124  		}
  3125  
  3126  		// integer, same width, same sign
  3127  		return v
  3128  
  3129  	case ir.OCONV:
  3130  		n := n.(*ir.ConvExpr)
  3131  		x := s.expr(n.X)
  3132  		return s.conv(n, x, n.X.Type(), n.Type())
  3133  
  3134  	case ir.ODOTTYPE:
  3135  		n := n.(*ir.TypeAssertExpr)
  3136  		res, _ := s.dottype(n, false)
  3137  		return res
  3138  
  3139  	case ir.ODYNAMICDOTTYPE:
  3140  		n := n.(*ir.DynamicTypeAssertExpr)
  3141  		res, _ := s.dynamicDottype(n, false)
  3142  		return res
  3143  
  3144  	// binary ops
  3145  	case ir.OLT, ir.OEQ, ir.ONE, ir.OLE, ir.OGE, ir.OGT:
  3146  		n := n.(*ir.BinaryExpr)
  3147  		a := s.expr(n.X)
  3148  		b := s.expr(n.Y)
  3149  		if n.X.Type().IsComplex() {
  3150  			pt := types.FloatForComplex(n.X.Type())
  3151  			op := s.ssaOp(ir.OEQ, pt)
  3152  			r := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
  3153  			i := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
  3154  			c := s.newValue2(ssa.OpAndB, types.Types[types.TBOOL], r, i)
  3155  			switch n.Op() {
  3156  			case ir.OEQ:
  3157  				return c
  3158  			case ir.ONE:
  3159  				return s.newValue1(ssa.OpNot, types.Types[types.TBOOL], c)
  3160  			default:
  3161  				s.Fatalf("ordered complex compare %v", n.Op())
  3162  			}
  3163  		}
  3164  
  3165  		// Convert OGE and OGT into OLE and OLT.
  3166  		op := n.Op()
  3167  		switch op {
  3168  		case ir.OGE:
  3169  			op, a, b = ir.OLE, b, a
  3170  		case ir.OGT:
  3171  			op, a, b = ir.OLT, b, a
  3172  		}
  3173  		if n.X.Type().IsFloat() {
  3174  			// float comparison
  3175  			return s.newValueOrSfCall2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3176  		}
  3177  		// integer comparison
  3178  		return s.newValue2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3179  	case ir.OMUL:
  3180  		n := n.(*ir.BinaryExpr)
  3181  		a := s.expr(n.X)
  3182  		b := s.expr(n.Y)
  3183  		if n.Type().IsComplex() {
  3184  			mulop := ssa.OpMul64F
  3185  			addop := ssa.OpAdd64F
  3186  			subop := ssa.OpSub64F
  3187  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3188  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3189  
  3190  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3191  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3192  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3193  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3194  
  3195  			if pt != wt { // Widen for calculation
  3196  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3197  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3198  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3199  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3200  			}
  3201  
  3202  			xreal := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3203  			ximag := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, bimag), s.newValueOrSfCall2(mulop, wt, aimag, breal))
  3204  
  3205  			if pt != wt { // Narrow to store back
  3206  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3207  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3208  			}
  3209  
  3210  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3211  		}
  3212  
  3213  		if n.Type().IsFloat() {
  3214  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3215  		}
  3216  
  3217  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3218  
  3219  	case ir.ODIV:
  3220  		n := n.(*ir.BinaryExpr)
  3221  		a := s.expr(n.X)
  3222  		b := s.expr(n.Y)
  3223  		if n.Type().IsComplex() {
  3224  			// TODO this is not executed because the front-end substitutes a runtime call.
  3225  			// That probably ought to change; with modest optimization the widen/narrow
  3226  			// conversions could all be elided in larger expression trees.
  3227  			mulop := ssa.OpMul64F
  3228  			addop := ssa.OpAdd64F
  3229  			subop := ssa.OpSub64F
  3230  			divop := ssa.OpDiv64F
  3231  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3232  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3233  
  3234  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3235  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3236  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3237  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3238  
  3239  			if pt != wt { // Widen for calculation
  3240  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3241  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3242  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3243  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3244  			}
  3245  
  3246  			denom := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, breal, breal), s.newValueOrSfCall2(mulop, wt, bimag, bimag))
  3247  			xreal := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3248  			ximag := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, aimag, breal), s.newValueOrSfCall2(mulop, wt, areal, bimag))
  3249  
  3250  			// TODO not sure if this is best done in wide precision or narrow
  3251  			// Double-rounding might be an issue.
  3252  			// Note that the pre-SSA implementation does the entire calculation
  3253  			// in wide format, so wide is compatible.
  3254  			xreal = s.newValueOrSfCall2(divop, wt, xreal, denom)
  3255  			ximag = s.newValueOrSfCall2(divop, wt, ximag, denom)
  3256  
  3257  			if pt != wt { // Narrow to store back
  3258  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3259  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3260  			}
  3261  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3262  		}
  3263  		if n.Type().IsFloat() {
  3264  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3265  		}
  3266  		return s.intDivide(n, a, b)
  3267  	case ir.OMOD:
  3268  		n := n.(*ir.BinaryExpr)
  3269  		a := s.expr(n.X)
  3270  		b := s.expr(n.Y)
  3271  		return s.intDivide(n, a, b)
  3272  	case ir.OADD, ir.OSUB:
  3273  		n := n.(*ir.BinaryExpr)
  3274  		a := s.expr(n.X)
  3275  		b := s.expr(n.Y)
  3276  		if n.Type().IsComplex() {
  3277  			pt := types.FloatForComplex(n.Type())
  3278  			op := s.ssaOp(n.Op(), pt)
  3279  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3280  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
  3281  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
  3282  		}
  3283  		if n.Type().IsFloat() {
  3284  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3285  		}
  3286  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3287  	case ir.OAND, ir.OOR, ir.OXOR:
  3288  		n := n.(*ir.BinaryExpr)
  3289  		a := s.expr(n.X)
  3290  		b := s.expr(n.Y)
  3291  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3292  	case ir.OANDNOT:
  3293  		n := n.(*ir.BinaryExpr)
  3294  		a := s.expr(n.X)
  3295  		b := s.expr(n.Y)
  3296  		b = s.newValue1(s.ssaOp(ir.OBITNOT, b.Type), b.Type, b)
  3297  		return s.newValue2(s.ssaOp(ir.OAND, n.Type()), a.Type, a, b)
  3298  	case ir.OLSH, ir.ORSH:
  3299  		n := n.(*ir.BinaryExpr)
  3300  		a := s.expr(n.X)
  3301  		b := s.expr(n.Y)
  3302  		bt := b.Type
  3303  		if bt.IsSigned() {
  3304  			cmp := s.newValue2(s.ssaOp(ir.OLE, bt), types.Types[types.TBOOL], s.zeroVal(bt), b)
  3305  			s.check(cmp, ir.Syms.Panicshift)
  3306  			bt = bt.ToUnsigned()
  3307  		}
  3308  		return s.newValue2(s.ssaShiftOp(n.Op(), n.Type(), bt), a.Type, a, b)
  3309  	case ir.OANDAND, ir.OOROR:
  3310  		// To implement OANDAND (and OOROR), we introduce a
  3311  		// new temporary variable to hold the result. The
  3312  		// variable is associated with the OANDAND node in the
  3313  		// s.vars table (normally variables are only
  3314  		// associated with ONAME nodes). We convert
  3315  		//     A && B
  3316  		// to
  3317  		//     var = A
  3318  		//     if var {
  3319  		//         var = B
  3320  		//     }
  3321  		// Using var in the subsequent block introduces the
  3322  		// necessary phi variable.
  3323  		n := n.(*ir.LogicalExpr)
  3324  		el := s.expr(n.X)
  3325  		s.vars[n] = el
  3326  
  3327  		b := s.endBlock()
  3328  		b.Kind = ssa.BlockIf
  3329  		b.SetControl(el)
  3330  		// In theory, we should set b.Likely here based on context.
  3331  		// However, gc only gives us likeliness hints
  3332  		// in a single place, for plain OIF statements,
  3333  		// and passing around context is finicky, so don't bother for now.
  3334  
  3335  		bRight := s.f.NewBlock(ssa.BlockPlain)
  3336  		bResult := s.f.NewBlock(ssa.BlockPlain)
  3337  		if n.Op() == ir.OANDAND {
  3338  			b.AddEdgeTo(bRight)
  3339  			b.AddEdgeTo(bResult)
  3340  		} else if n.Op() == ir.OOROR {
  3341  			b.AddEdgeTo(bResult)
  3342  			b.AddEdgeTo(bRight)
  3343  		}
  3344  
  3345  		s.startBlock(bRight)
  3346  		er := s.expr(n.Y)
  3347  		s.vars[n] = er
  3348  
  3349  		b = s.endBlock()
  3350  		b.AddEdgeTo(bResult)
  3351  
  3352  		s.startBlock(bResult)
  3353  		return s.variable(n, types.Types[types.TBOOL])
  3354  	case ir.OCOMPLEX:
  3355  		n := n.(*ir.BinaryExpr)
  3356  		r := s.expr(n.X)
  3357  		i := s.expr(n.Y)
  3358  		return s.newValue2(ssa.OpComplexMake, n.Type(), r, i)
  3359  
  3360  	// unary ops
  3361  	case ir.ONEG:
  3362  		n := n.(*ir.UnaryExpr)
  3363  		a := s.expr(n.X)
  3364  		if n.Type().IsComplex() {
  3365  			tp := types.FloatForComplex(n.Type())
  3366  			negop := s.ssaOp(n.Op(), tp)
  3367  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3368  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexReal, tp, a)),
  3369  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexImag, tp, a)))
  3370  		}
  3371  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3372  	case ir.ONOT, ir.OBITNOT:
  3373  		n := n.(*ir.UnaryExpr)
  3374  		a := s.expr(n.X)
  3375  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3376  	case ir.OIMAG, ir.OREAL:
  3377  		n := n.(*ir.UnaryExpr)
  3378  		a := s.expr(n.X)
  3379  		return s.newValue1(s.ssaOp(n.Op(), n.X.Type()), n.Type(), a)
  3380  	case ir.OPLUS:
  3381  		n := n.(*ir.UnaryExpr)
  3382  		return s.expr(n.X)
  3383  
  3384  	case ir.OADDR:
  3385  		n := n.(*ir.AddrExpr)
  3386  		return s.addr(n.X)
  3387  
  3388  	case ir.ORESULT:
  3389  		n := n.(*ir.ResultExpr)
  3390  		if s.prevCall == nil || s.prevCall.Op != ssa.OpStaticLECall && s.prevCall.Op != ssa.OpInterLECall && s.prevCall.Op != ssa.OpClosureLECall {
  3391  			panic("Expected to see a previous call")
  3392  		}
  3393  		which := n.Index
  3394  		if which == -1 {
  3395  			panic(fmt.Errorf("ORESULT %v does not match call %s", n, s.prevCall))
  3396  		}
  3397  		return s.resultOfCall(s.prevCall, which, n.Type())
  3398  
  3399  	case ir.ODEREF:
  3400  		n := n.(*ir.StarExpr)
  3401  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3402  		return s.load(n.Type(), p)
  3403  
  3404  	case ir.ODOT:
  3405  		n := n.(*ir.SelectorExpr)
  3406  		if n.X.Op() == ir.OSTRUCTLIT {
  3407  			// All literals with nonzero fields have already been
  3408  			// rewritten during walk. Any that remain are just T{}
  3409  			// or equivalents. Use the zero value.
  3410  			if !ir.IsZero(n.X) {
  3411  				s.Fatalf("literal with nonzero value in SSA: %v", n.X)
  3412  			}
  3413  			return s.zeroVal(n.Type())
  3414  		}
  3415  		// If n is addressable and can't be represented in
  3416  		// SSA, then load just the selected field. This
  3417  		// prevents false memory dependencies in race/msan/asan
  3418  		// instrumentation.
  3419  		if ir.IsAddressable(n) && !s.canSSA(n) {
  3420  			p := s.addr(n)
  3421  			return s.load(n.Type(), p)
  3422  		}
  3423  		v := s.expr(n.X)
  3424  		return s.newValue1I(ssa.OpStructSelect, n.Type(), int64(fieldIdx(n)), v)
  3425  
  3426  	case ir.ODOTPTR:
  3427  		n := n.(*ir.SelectorExpr)
  3428  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3429  		p = s.newValue1I(ssa.OpOffPtr, types.NewPtr(n.Type()), n.Offset(), p)
  3430  		return s.load(n.Type(), p)
  3431  
  3432  	case ir.OINDEX:
  3433  		n := n.(*ir.IndexExpr)
  3434  		switch {
  3435  		case n.X.Type().IsString():
  3436  			if n.Bounded() && ir.IsConst(n.X, constant.String) && ir.IsConst(n.Index, constant.Int) {
  3437  				// Replace "abc"[1] with 'b'.
  3438  				// Delayed until now because "abc"[1] is not an ideal constant.
  3439  				// See test/fixedbugs/issue11370.go.
  3440  				return s.newValue0I(ssa.OpConst8, types.Types[types.TUINT8], int64(int8(ir.StringVal(n.X)[ir.Int64Val(n.Index)])))
  3441  			}
  3442  			a := s.expr(n.X)
  3443  			i := s.expr(n.Index)
  3444  			len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3445  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  3446  			ptrtyp := s.f.Config.Types.BytePtr
  3447  			ptr := s.newValue1(ssa.OpStringPtr, ptrtyp, a)
  3448  			if ir.IsConst(n.Index, constant.Int) {
  3449  				ptr = s.newValue1I(ssa.OpOffPtr, ptrtyp, ir.Int64Val(n.Index), ptr)
  3450  			} else {
  3451  				ptr = s.newValue2(ssa.OpAddPtr, ptrtyp, ptr, i)
  3452  			}
  3453  			return s.load(types.Types[types.TUINT8], ptr)
  3454  		case n.X.Type().IsSlice():
  3455  			p := s.addr(n)
  3456  			return s.load(n.X.Type().Elem(), p)
  3457  		case n.X.Type().IsArray():
  3458  			if ssa.CanSSA(n.X.Type()) {
  3459  				// SSA can handle arrays of length at most 1.
  3460  				bound := n.X.Type().NumElem()
  3461  				a := s.expr(n.X)
  3462  				i := s.expr(n.Index)
  3463  				if bound == 0 {
  3464  					// Bounds check will never succeed.  Might as well
  3465  					// use constants for the bounds check.
  3466  					z := s.constInt(types.Types[types.TINT], 0)
  3467  					s.boundsCheck(z, z, ssa.BoundsIndex, false)
  3468  					// The return value won't be live, return junk.
  3469  					// But not quite junk, in case bounds checks are turned off. See issue 48092.
  3470  					return s.zeroVal(n.Type())
  3471  				}
  3472  				len := s.constInt(types.Types[types.TINT], bound)
  3473  				s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded()) // checks i == 0
  3474  				return s.newValue1I(ssa.OpArraySelect, n.Type(), 0, a)
  3475  			}
  3476  			p := s.addr(n)
  3477  			return s.load(n.X.Type().Elem(), p)
  3478  		default:
  3479  			s.Fatalf("bad type for index %v", n.X.Type())
  3480  			return nil
  3481  		}
  3482  
  3483  	case ir.OLEN, ir.OCAP:
  3484  		n := n.(*ir.UnaryExpr)
  3485  		// Note: all constant cases are handled by the frontend. If len or cap
  3486  		// makes it here, we want the side effects of the argument. See issue 72844.
  3487  		a := s.expr(n.X)
  3488  		t := n.X.Type()
  3489  		switch {
  3490  		case t.IsSlice():
  3491  			op := ssa.OpSliceLen
  3492  			if n.Op() == ir.OCAP {
  3493  				op = ssa.OpSliceCap
  3494  			}
  3495  			return s.newValue1(op, types.Types[types.TINT], a)
  3496  		case t.IsString(): // string; not reachable for OCAP
  3497  			return s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3498  		case t.IsMap(), t.IsChan():
  3499  			return s.referenceTypeBuiltin(n, a)
  3500  		case t.IsArray():
  3501  			return s.constInt(types.Types[types.TINT], t.NumElem())
  3502  		case t.IsPtr() && t.Elem().IsArray():
  3503  			return s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  3504  		default:
  3505  			s.Fatalf("bad type in len/cap: %v", t)
  3506  			return nil
  3507  		}
  3508  
  3509  	case ir.OSPTR:
  3510  		n := n.(*ir.UnaryExpr)
  3511  		a := s.expr(n.X)
  3512  		if n.X.Type().IsSlice() {
  3513  			if n.Bounded() {
  3514  				return s.newValue1(ssa.OpSlicePtr, n.Type(), a)
  3515  			}
  3516  			return s.newValue1(ssa.OpSlicePtrUnchecked, n.Type(), a)
  3517  		} else {
  3518  			return s.newValue1(ssa.OpStringPtr, n.Type(), a)
  3519  		}
  3520  
  3521  	case ir.OITAB:
  3522  		n := n.(*ir.UnaryExpr)
  3523  		a := s.expr(n.X)
  3524  		return s.newValue1(ssa.OpITab, n.Type(), a)
  3525  
  3526  	case ir.OIDATA:
  3527  		n := n.(*ir.UnaryExpr)
  3528  		a := s.expr(n.X)
  3529  		return s.newValue1(ssa.OpIData, n.Type(), a)
  3530  
  3531  	case ir.OMAKEFACE:
  3532  		n := n.(*ir.BinaryExpr)
  3533  		tab := s.expr(n.X)
  3534  		data := s.expr(n.Y)
  3535  		return s.newValue2(ssa.OpIMake, n.Type(), tab, data)
  3536  
  3537  	case ir.OSLICEHEADER:
  3538  		n := n.(*ir.SliceHeaderExpr)
  3539  		p := s.expr(n.Ptr)
  3540  		l := s.expr(n.Len)
  3541  		c := s.expr(n.Cap)
  3542  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3543  
  3544  	case ir.OSTRINGHEADER:
  3545  		n := n.(*ir.StringHeaderExpr)
  3546  		p := s.expr(n.Ptr)
  3547  		l := s.expr(n.Len)
  3548  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3549  
  3550  	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR:
  3551  		n := n.(*ir.SliceExpr)
  3552  		check := s.checkPtrEnabled && n.Op() == ir.OSLICE3ARR && n.X.Op() == ir.OCONVNOP && n.X.(*ir.ConvExpr).X.Type().IsUnsafePtr()
  3553  		v := s.exprCheckPtr(n.X, !check)
  3554  		var i, j, k *ssa.Value
  3555  		if n.Low != nil {
  3556  			i = s.expr(n.Low)
  3557  		}
  3558  		if n.High != nil {
  3559  			j = s.expr(n.High)
  3560  		}
  3561  		if n.Max != nil {
  3562  			k = s.expr(n.Max)
  3563  		}
  3564  		p, l, c := s.slice(v, i, j, k, n.Bounded())
  3565  		if check {
  3566  			// Emit checkptr instrumentation after bound check to prevent false positive, see #46938.
  3567  			s.checkPtrAlignment(n.X.(*ir.ConvExpr), v, s.conv(n.Max, k, k.Type, types.Types[types.TUINTPTR]))
  3568  		}
  3569  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3570  
  3571  	case ir.OSLICESTR:
  3572  		n := n.(*ir.SliceExpr)
  3573  		v := s.expr(n.X)
  3574  		var i, j *ssa.Value
  3575  		if n.Low != nil {
  3576  			i = s.expr(n.Low)
  3577  		}
  3578  		if n.High != nil {
  3579  			j = s.expr(n.High)
  3580  		}
  3581  		p, l, _ := s.slice(v, i, j, nil, n.Bounded())
  3582  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3583  
  3584  	case ir.OSLICE2ARRPTR:
  3585  		// if arrlen > slice.len {
  3586  		//   panic(...)
  3587  		// }
  3588  		// slice.ptr
  3589  		n := n.(*ir.ConvExpr)
  3590  		v := s.expr(n.X)
  3591  		nelem := n.Type().Elem().NumElem()
  3592  		arrlen := s.constInt(types.Types[types.TINT], nelem)
  3593  		cap := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  3594  		s.boundsCheck(arrlen, cap, ssa.BoundsConvert, false)
  3595  		op := ssa.OpSlicePtr
  3596  		if nelem == 0 {
  3597  			op = ssa.OpSlicePtrUnchecked
  3598  		}
  3599  		return s.newValue1(op, n.Type(), v)
  3600  
  3601  	case ir.OCALLFUNC:
  3602  		n := n.(*ir.CallExpr)
  3603  		if ir.IsIntrinsicCall(n) {
  3604  			return s.intrinsicCall(n)
  3605  		}
  3606  		fallthrough
  3607  
  3608  	case ir.OCALLINTER:
  3609  		n := n.(*ir.CallExpr)
  3610  		return s.callResult(n, callNormal)
  3611  
  3612  	case ir.OGETG:
  3613  		n := n.(*ir.CallExpr)
  3614  		return s.newValue1(ssa.OpGetG, n.Type(), s.mem())
  3615  
  3616  	case ir.OGETCALLERSP:
  3617  		n := n.(*ir.CallExpr)
  3618  		return s.newValue1(ssa.OpGetCallerSP, n.Type(), s.mem())
  3619  
  3620  	case ir.OAPPEND:
  3621  		return s.append(n.(*ir.CallExpr), false)
  3622  
  3623  	case ir.OMIN, ir.OMAX:
  3624  		return s.minMax(n.(*ir.CallExpr))
  3625  
  3626  	case ir.OSTRUCTLIT, ir.OARRAYLIT:
  3627  		// All literals with nonzero fields have already been
  3628  		// rewritten during walk. Any that remain are just T{}
  3629  		// or equivalents. Use the zero value.
  3630  		n := n.(*ir.CompLitExpr)
  3631  		if !ir.IsZero(n) {
  3632  			s.Fatalf("literal with nonzero value in SSA: %v", n)
  3633  		}
  3634  		return s.zeroVal(n.Type())
  3635  
  3636  	case ir.ONEW:
  3637  		n := n.(*ir.UnaryExpr)
  3638  		var rtype *ssa.Value
  3639  		if x, ok := n.X.(*ir.DynamicType); ok && x.Op() == ir.ODYNAMICTYPE {
  3640  			rtype = s.expr(x.RType)
  3641  		}
  3642  		return s.newObject(n.Type().Elem(), rtype)
  3643  
  3644  	case ir.OUNSAFEADD:
  3645  		n := n.(*ir.BinaryExpr)
  3646  		ptr := s.expr(n.X)
  3647  		len := s.expr(n.Y)
  3648  
  3649  		// Force len to uintptr to prevent misuse of garbage bits in the
  3650  		// upper part of the register (#48536).
  3651  		len = s.conv(n, len, len.Type, types.Types[types.TUINTPTR])
  3652  
  3653  		return s.newValue2(ssa.OpAddPtr, n.Type(), ptr, len)
  3654  
  3655  	default:
  3656  		s.Fatalf("unhandled expr %v", n.Op())
  3657  		return nil
  3658  	}
  3659  }
  3660  
  3661  func (s *state) resultOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3662  	aux := c.Aux.(*ssa.AuxCall)
  3663  	pa := aux.ParamAssignmentForResult(which)
  3664  	// TODO(register args) determine if in-memory TypeOK is better loaded early from SelectNAddr or later when SelectN is expanded.
  3665  	// SelectN is better for pattern-matching and possible call-aware analysis we might want to do in the future.
  3666  	if len(pa.Registers) == 0 && !ssa.CanSSA(t) {
  3667  		addr := s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3668  		return s.rawLoad(t, addr)
  3669  	}
  3670  	return s.newValue1I(ssa.OpSelectN, t, which, c)
  3671  }
  3672  
  3673  func (s *state) resultAddrOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3674  	aux := c.Aux.(*ssa.AuxCall)
  3675  	pa := aux.ParamAssignmentForResult(which)
  3676  	if len(pa.Registers) == 0 {
  3677  		return s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3678  	}
  3679  	_, addr := s.temp(c.Pos, t)
  3680  	rval := s.newValue1I(ssa.OpSelectN, t, which, c)
  3681  	s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, addr, rval, s.mem(), false)
  3682  	return addr
  3683  }
  3684  
  3685  // append converts an OAPPEND node to SSA.
  3686  // If inplace is false, it converts the OAPPEND expression n to an ssa.Value,
  3687  // adds it to s, and returns the Value.
  3688  // If inplace is true, it writes the result of the OAPPEND expression n
  3689  // back to the slice being appended to, and returns nil.
  3690  // inplace MUST be set to false if the slice can be SSA'd.
  3691  // Note: this code only handles fixed-count appends. Dotdotdot appends
  3692  // have already been rewritten at this point (by walk).
  3693  func (s *state) append(n *ir.CallExpr, inplace bool) *ssa.Value {
  3694  	// If inplace is false, process as expression "append(s, e1, e2, e3)":
  3695  	//
  3696  	// ptr, len, cap := s
  3697  	// len += 3
  3698  	// if uint(len) > uint(cap) {
  3699  	//     ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3700  	//     Note that len is unmodified by growslice.
  3701  	// }
  3702  	// // with write barriers, if needed:
  3703  	// *(ptr+(len-3)) = e1
  3704  	// *(ptr+(len-2)) = e2
  3705  	// *(ptr+(len-1)) = e3
  3706  	// return makeslice(ptr, len, cap)
  3707  	//
  3708  	//
  3709  	// If inplace is true, process as statement "s = append(s, e1, e2, e3)":
  3710  	//
  3711  	// a := &s
  3712  	// ptr, len, cap := s
  3713  	// len += 3
  3714  	// if uint(len) > uint(cap) {
  3715  	//    ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3716  	//    vardef(a)    // if necessary, advise liveness we are writing a new a
  3717  	//    *a.cap = cap // write before ptr to avoid a spill
  3718  	//    *a.ptr = ptr // with write barrier
  3719  	// }
  3720  	// *a.len = len
  3721  	// // with write barriers, if needed:
  3722  	// *(ptr+(len-3)) = e1
  3723  	// *(ptr+(len-2)) = e2
  3724  	// *(ptr+(len-1)) = e3
  3725  
  3726  	et := n.Type().Elem()
  3727  	pt := types.NewPtr(et)
  3728  
  3729  	// Evaluate slice
  3730  	sn := n.Args[0] // the slice node is the first in the list
  3731  	var slice, addr *ssa.Value
  3732  	if inplace {
  3733  		addr = s.addr(sn)
  3734  		slice = s.load(n.Type(), addr)
  3735  	} else {
  3736  		slice = s.expr(sn)
  3737  	}
  3738  
  3739  	// Allocate new blocks
  3740  	grow := s.f.NewBlock(ssa.BlockPlain)
  3741  	assign := s.f.NewBlock(ssa.BlockPlain)
  3742  
  3743  	// Decomposse input slice.
  3744  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  3745  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3746  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  3747  
  3748  	// Add number of new elements to length.
  3749  	nargs := s.constInt(types.Types[types.TINT], int64(len(n.Args)-1))
  3750  	oldLen := l
  3751  	l = s.newValue2(s.ssaOp(ir.OADD, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  3752  
  3753  	// Decide if we need to grow
  3754  	cmp := s.newValue2(s.ssaOp(ir.OLT, types.Types[types.TUINT]), types.Types[types.TBOOL], c, l)
  3755  
  3756  	// Record values of ptr/len/cap before branch.
  3757  	s.vars[ptrVar] = p
  3758  	s.vars[lenVar] = l
  3759  	if !inplace {
  3760  		s.vars[capVar] = c
  3761  	}
  3762  
  3763  	b := s.endBlock()
  3764  	b.Kind = ssa.BlockIf
  3765  	b.Likely = ssa.BranchUnlikely
  3766  	b.SetControl(cmp)
  3767  	b.AddEdgeTo(grow)
  3768  	b.AddEdgeTo(assign)
  3769  
  3770  	// If the result of the append does not escape, we can use
  3771  	// a stack-allocated backing store if len is small enough.
  3772  	// A stack-allocated backing store could be used at every
  3773  	// append that qualifies, but we limit it in some cases to
  3774  	// avoid wasted code and stack space.
  3775  	// TODO: handle ... append case.
  3776  	maxStackSize := int64(base.Debug.VariableMakeThreshold)
  3777  	if !inplace && n.Esc() == ir.EscNone && et.Size() > 0 && et.Size() <= maxStackSize && base.Flag.N == 0 && base.VariableMakeHash.MatchPos(n.Pos(), nil) && !s.appendTargets[sn] {
  3778  		// if l <= K {
  3779  		//   if !used {
  3780  		//     if oldLen == 0 {
  3781  		//       var store [K]T
  3782  		//       s = store[:l:K]
  3783  		//       used = true
  3784  		//     }
  3785  		//   }
  3786  		// }
  3787  		// ... if we didn't use the stack backing store, call growslice ...
  3788  		//
  3789  		// oldLen==0 is not strictly necessary, but requiring it means
  3790  		// we don't have to worry about copying existing elements.
  3791  		// Allowing oldLen>0 would add complication. Worth it? I would guess not.
  3792  		//
  3793  		// TODO: instead of the used boolean, we could insist that this only applies
  3794  		// to monotonic slices, those which once they have >0 entries never go back
  3795  		// to 0 entries. Then oldLen==0 is enough.
  3796  		//
  3797  		// We also do this for append(x, ...) once for every x.
  3798  		// It is ok to do it more often, but it is probably helpful only for
  3799  		// the first instance. TODO: this could use more tuning. Using ir.Node
  3800  		// as the key works for *ir.Name instances but probably nothing else.
  3801  		if s.appendTargets == nil {
  3802  			s.appendTargets = map[ir.Node]bool{}
  3803  		}
  3804  		s.appendTargets[sn] = true
  3805  
  3806  		K := maxStackSize / et.Size() // rounds down
  3807  		KT := types.NewArray(et, K)
  3808  		KT.SetNoalg(true)
  3809  		types.CalcArraySize(KT)
  3810  		// Align more than naturally for the type KT. See issue 73199.
  3811  		align := types.NewArray(types.Types[types.TUINTPTR], 0)
  3812  		types.CalcArraySize(align)
  3813  		storeTyp := types.NewStruct([]*types.Field{
  3814  			{Sym: types.BlankSym, Type: align},
  3815  			{Sym: types.BlankSym, Type: KT},
  3816  		})
  3817  		storeTyp.SetNoalg(true)
  3818  		types.CalcStructSize(storeTyp)
  3819  
  3820  		usedTestBlock := s.f.NewBlock(ssa.BlockPlain)
  3821  		oldLenTestBlock := s.f.NewBlock(ssa.BlockPlain)
  3822  		bodyBlock := s.f.NewBlock(ssa.BlockPlain)
  3823  		growSlice := s.f.NewBlock(ssa.BlockPlain)
  3824  
  3825  		// Make "used" boolean.
  3826  		tBool := types.Types[types.TBOOL]
  3827  		used := typecheck.TempAt(n.Pos(), s.curfn, tBool)
  3828  		s.defvars[s.f.Entry.ID][used] = s.constBool(false) // initialize this variable at fn entry
  3829  
  3830  		// Make backing store variable.
  3831  		tInt := types.Types[types.TINT]
  3832  		backingStore := typecheck.TempAt(n.Pos(), s.curfn, storeTyp)
  3833  		backingStore.SetAddrtaken(true)
  3834  
  3835  		// if l <= K
  3836  		s.startBlock(grow)
  3837  		kTest := s.newValue2(s.ssaOp(ir.OLE, tInt), tBool, l, s.constInt(tInt, K))
  3838  		b := s.endBlock()
  3839  		b.Kind = ssa.BlockIf
  3840  		b.SetControl(kTest)
  3841  		b.AddEdgeTo(usedTestBlock)
  3842  		b.AddEdgeTo(growSlice)
  3843  		b.Likely = ssa.BranchLikely
  3844  
  3845  		// if !used
  3846  		s.startBlock(usedTestBlock)
  3847  		usedTest := s.newValue1(ssa.OpNot, tBool, s.expr(used))
  3848  		b = s.endBlock()
  3849  		b.Kind = ssa.BlockIf
  3850  		b.SetControl(usedTest)
  3851  		b.AddEdgeTo(oldLenTestBlock)
  3852  		b.AddEdgeTo(growSlice)
  3853  		b.Likely = ssa.BranchLikely
  3854  
  3855  		// if oldLen == 0
  3856  		s.startBlock(oldLenTestBlock)
  3857  		oldLenTest := s.newValue2(s.ssaOp(ir.OEQ, tInt), tBool, oldLen, s.constInt(tInt, 0))
  3858  		b = s.endBlock()
  3859  		b.Kind = ssa.BlockIf
  3860  		b.SetControl(oldLenTest)
  3861  		b.AddEdgeTo(bodyBlock)
  3862  		b.AddEdgeTo(growSlice)
  3863  		b.Likely = ssa.BranchLikely
  3864  
  3865  		// var store struct { _ [0]uintptr; arr [K]T }
  3866  		s.startBlock(bodyBlock)
  3867  		if et.HasPointers() {
  3868  			s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, backingStore, s.mem())
  3869  		}
  3870  		addr := s.addr(backingStore)
  3871  		s.zero(storeTyp, addr)
  3872  
  3873  		// s = store.arr[:l:K]
  3874  		s.vars[ptrVar] = addr
  3875  		s.vars[lenVar] = l // nargs would also be ok because of the oldLen==0 test.
  3876  		s.vars[capVar] = s.constInt(tInt, K)
  3877  
  3878  		// used = true
  3879  		s.assign(used, s.constBool(true), false, 0)
  3880  		b = s.endBlock()
  3881  		b.AddEdgeTo(assign)
  3882  
  3883  		// New block to use for growslice call.
  3884  		grow = growSlice
  3885  	}
  3886  
  3887  	// Call growslice
  3888  	s.startBlock(grow)
  3889  	taddr := s.expr(n.Fun)
  3890  	r := s.rtcall(ir.Syms.Growslice, true, []*types.Type{n.Type()}, p, l, c, nargs, taddr)
  3891  
  3892  	// Decompose output slice
  3893  	p = s.newValue1(ssa.OpSlicePtr, pt, r[0])
  3894  	l = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], r[0])
  3895  	c = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], r[0])
  3896  
  3897  	s.vars[ptrVar] = p
  3898  	s.vars[lenVar] = l
  3899  	s.vars[capVar] = c
  3900  	if inplace {
  3901  		if sn.Op() == ir.ONAME {
  3902  			sn := sn.(*ir.Name)
  3903  			if sn.Class != ir.PEXTERN {
  3904  				// Tell liveness we're about to build a new slice
  3905  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, sn, s.mem())
  3906  			}
  3907  		}
  3908  		capaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceCapOffset, addr)
  3909  		s.store(types.Types[types.TINT], capaddr, c)
  3910  		s.store(pt, addr, p)
  3911  	}
  3912  
  3913  	b = s.endBlock()
  3914  	b.AddEdgeTo(assign)
  3915  
  3916  	// assign new elements to slots
  3917  	s.startBlock(assign)
  3918  	p = s.variable(ptrVar, pt)                      // generates phi for ptr
  3919  	l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  3920  	if !inplace {
  3921  		c = s.variable(capVar, types.Types[types.TINT]) // generates phi for cap
  3922  	}
  3923  
  3924  	if inplace {
  3925  		// Update length in place.
  3926  		// We have to wait until here to make sure growslice succeeded.
  3927  		lenaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceLenOffset, addr)
  3928  		s.store(types.Types[types.TINT], lenaddr, l)
  3929  	}
  3930  
  3931  	// Evaluate args
  3932  	type argRec struct {
  3933  		// if store is true, we're appending the value v.  If false, we're appending the
  3934  		// value at *v.
  3935  		v     *ssa.Value
  3936  		store bool
  3937  	}
  3938  	args := make([]argRec, 0, len(n.Args[1:]))
  3939  	for _, n := range n.Args[1:] {
  3940  		if ssa.CanSSA(n.Type()) {
  3941  			args = append(args, argRec{v: s.expr(n), store: true})
  3942  		} else {
  3943  			v := s.addr(n)
  3944  			args = append(args, argRec{v: v})
  3945  		}
  3946  	}
  3947  
  3948  	// Write args into slice.
  3949  	oldLen = s.newValue2(s.ssaOp(ir.OSUB, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  3950  	p2 := s.newValue2(ssa.OpPtrIndex, pt, p, oldLen)
  3951  	for i, arg := range args {
  3952  		addr := s.newValue2(ssa.OpPtrIndex, pt, p2, s.constInt(types.Types[types.TINT], int64(i)))
  3953  		if arg.store {
  3954  			s.storeType(et, addr, arg.v, 0, true)
  3955  		} else {
  3956  			s.move(et, addr, arg.v)
  3957  		}
  3958  	}
  3959  
  3960  	// The following deletions have no practical effect at this time
  3961  	// because state.vars has been reset by the preceding state.startBlock.
  3962  	// They only enforce the fact that these variables are no longer need in
  3963  	// the current scope.
  3964  	delete(s.vars, ptrVar)
  3965  	delete(s.vars, lenVar)
  3966  	if !inplace {
  3967  		delete(s.vars, capVar)
  3968  	}
  3969  
  3970  	// make result
  3971  	if inplace {
  3972  		return nil
  3973  	}
  3974  	return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3975  }
  3976  
  3977  // minMax converts an OMIN/OMAX builtin call into SSA.
  3978  func (s *state) minMax(n *ir.CallExpr) *ssa.Value {
  3979  	// The OMIN/OMAX builtin is variadic, but its semantics are
  3980  	// equivalent to left-folding a binary min/max operation across the
  3981  	// arguments list.
  3982  	fold := func(op func(x, a *ssa.Value) *ssa.Value) *ssa.Value {
  3983  		x := s.expr(n.Args[0])
  3984  		for _, arg := range n.Args[1:] {
  3985  			x = op(x, s.expr(arg))
  3986  		}
  3987  		return x
  3988  	}
  3989  
  3990  	typ := n.Type()
  3991  
  3992  	if typ.IsFloat() || typ.IsString() {
  3993  		// min/max semantics for floats are tricky because of NaNs and
  3994  		// negative zero. Some architectures have instructions which
  3995  		// we can use to generate the right result. For others we must
  3996  		// call into the runtime instead.
  3997  		//
  3998  		// Strings are conceptually simpler, but we currently desugar
  3999  		// string comparisons during walk, not ssagen.
  4000  
  4001  		if typ.IsFloat() {
  4002  			hasIntrinsic := false
  4003  			switch Arch.LinkArch.Family {
  4004  			case sys.AMD64, sys.ARM64, sys.Loong64, sys.RISCV64:
  4005  				hasIntrinsic = true
  4006  			case sys.PPC64:
  4007  				hasIntrinsic = buildcfg.GOPPC64 >= 9
  4008  			}
  4009  
  4010  			if hasIntrinsic {
  4011  				var op ssa.Op
  4012  				switch {
  4013  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMIN:
  4014  					op = ssa.OpMin64F
  4015  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMAX:
  4016  					op = ssa.OpMax64F
  4017  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMIN:
  4018  					op = ssa.OpMin32F
  4019  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMAX:
  4020  					op = ssa.OpMax32F
  4021  				}
  4022  				return fold(func(x, a *ssa.Value) *ssa.Value {
  4023  					return s.newValue2(op, typ, x, a)
  4024  				})
  4025  			}
  4026  		}
  4027  		var name string
  4028  		switch typ.Kind() {
  4029  		case types.TFLOAT32:
  4030  			switch n.Op() {
  4031  			case ir.OMIN:
  4032  				name = "fmin32"
  4033  			case ir.OMAX:
  4034  				name = "fmax32"
  4035  			}
  4036  		case types.TFLOAT64:
  4037  			switch n.Op() {
  4038  			case ir.OMIN:
  4039  				name = "fmin64"
  4040  			case ir.OMAX:
  4041  				name = "fmax64"
  4042  			}
  4043  		case types.TSTRING:
  4044  			switch n.Op() {
  4045  			case ir.OMIN:
  4046  				name = "strmin"
  4047  			case ir.OMAX:
  4048  				name = "strmax"
  4049  			}
  4050  		}
  4051  		fn := typecheck.LookupRuntimeFunc(name)
  4052  
  4053  		return fold(func(x, a *ssa.Value) *ssa.Value {
  4054  			return s.rtcall(fn, true, []*types.Type{typ}, x, a)[0]
  4055  		})
  4056  	}
  4057  
  4058  	if typ.IsInteger() {
  4059  		if Arch.LinkArch.Family == sys.RISCV64 && buildcfg.GORISCV64 >= 22 && typ.Size() == 8 {
  4060  			var op ssa.Op
  4061  			switch {
  4062  			case typ.IsSigned() && n.Op() == ir.OMIN:
  4063  				op = ssa.OpMin64
  4064  			case typ.IsSigned() && n.Op() == ir.OMAX:
  4065  				op = ssa.OpMax64
  4066  			case typ.IsUnsigned() && n.Op() == ir.OMIN:
  4067  				op = ssa.OpMin64u
  4068  			case typ.IsUnsigned() && n.Op() == ir.OMAX:
  4069  				op = ssa.OpMax64u
  4070  			}
  4071  			return fold(func(x, a *ssa.Value) *ssa.Value {
  4072  				return s.newValue2(op, typ, x, a)
  4073  			})
  4074  		}
  4075  	}
  4076  
  4077  	lt := s.ssaOp(ir.OLT, typ)
  4078  
  4079  	return fold(func(x, a *ssa.Value) *ssa.Value {
  4080  		switch n.Op() {
  4081  		case ir.OMIN:
  4082  			// a < x ? a : x
  4083  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], a, x), a, x)
  4084  		case ir.OMAX:
  4085  			// x < a ? a : x
  4086  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], x, a), a, x)
  4087  		}
  4088  		panic("unreachable")
  4089  	})
  4090  }
  4091  
  4092  // ternary emits code to evaluate cond ? x : y.
  4093  func (s *state) ternary(cond, x, y *ssa.Value) *ssa.Value {
  4094  	// Note that we need a new ternaryVar each time (unlike okVar where we can
  4095  	// reuse the variable) because it might have a different type every time.
  4096  	ternaryVar := ssaMarker("ternary")
  4097  
  4098  	bThen := s.f.NewBlock(ssa.BlockPlain)
  4099  	bElse := s.f.NewBlock(ssa.BlockPlain)
  4100  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  4101  
  4102  	b := s.endBlock()
  4103  	b.Kind = ssa.BlockIf
  4104  	b.SetControl(cond)
  4105  	b.AddEdgeTo(bThen)
  4106  	b.AddEdgeTo(bElse)
  4107  
  4108  	s.startBlock(bThen)
  4109  	s.vars[ternaryVar] = x
  4110  	s.endBlock().AddEdgeTo(bEnd)
  4111  
  4112  	s.startBlock(bElse)
  4113  	s.vars[ternaryVar] = y
  4114  	s.endBlock().AddEdgeTo(bEnd)
  4115  
  4116  	s.startBlock(bEnd)
  4117  	r := s.variable(ternaryVar, x.Type)
  4118  	delete(s.vars, ternaryVar)
  4119  	return r
  4120  }
  4121  
  4122  // condBranch evaluates the boolean expression cond and branches to yes
  4123  // if cond is true and no if cond is false.
  4124  // This function is intended to handle && and || better than just calling
  4125  // s.expr(cond) and branching on the result.
  4126  func (s *state) condBranch(cond ir.Node, yes, no *ssa.Block, likely int8) {
  4127  	switch cond.Op() {
  4128  	case ir.OANDAND:
  4129  		cond := cond.(*ir.LogicalExpr)
  4130  		mid := s.f.NewBlock(ssa.BlockPlain)
  4131  		s.stmtList(cond.Init())
  4132  		s.condBranch(cond.X, mid, no, max(likely, 0))
  4133  		s.startBlock(mid)
  4134  		s.condBranch(cond.Y, yes, no, likely)
  4135  		return
  4136  		// Note: if likely==1, then both recursive calls pass 1.
  4137  		// If likely==-1, then we don't have enough information to decide
  4138  		// whether the first branch is likely or not. So we pass 0 for
  4139  		// the likeliness of the first branch.
  4140  		// TODO: have the frontend give us branch prediction hints for
  4141  		// OANDAND and OOROR nodes (if it ever has such info).
  4142  	case ir.OOROR:
  4143  		cond := cond.(*ir.LogicalExpr)
  4144  		mid := s.f.NewBlock(ssa.BlockPlain)
  4145  		s.stmtList(cond.Init())
  4146  		s.condBranch(cond.X, yes, mid, min(likely, 0))
  4147  		s.startBlock(mid)
  4148  		s.condBranch(cond.Y, yes, no, likely)
  4149  		return
  4150  		// Note: if likely==-1, then both recursive calls pass -1.
  4151  		// If likely==1, then we don't have enough info to decide
  4152  		// the likelihood of the first branch.
  4153  	case ir.ONOT:
  4154  		cond := cond.(*ir.UnaryExpr)
  4155  		s.stmtList(cond.Init())
  4156  		s.condBranch(cond.X, no, yes, -likely)
  4157  		return
  4158  	case ir.OCONVNOP:
  4159  		cond := cond.(*ir.ConvExpr)
  4160  		s.stmtList(cond.Init())
  4161  		s.condBranch(cond.X, yes, no, likely)
  4162  		return
  4163  	}
  4164  	c := s.expr(cond)
  4165  	b := s.endBlock()
  4166  	b.Kind = ssa.BlockIf
  4167  	b.SetControl(c)
  4168  	b.Likely = ssa.BranchPrediction(likely) // gc and ssa both use -1/0/+1 for likeliness
  4169  	b.AddEdgeTo(yes)
  4170  	b.AddEdgeTo(no)
  4171  }
  4172  
  4173  type skipMask uint8
  4174  
  4175  const (
  4176  	skipPtr skipMask = 1 << iota
  4177  	skipLen
  4178  	skipCap
  4179  )
  4180  
  4181  // assign does left = right.
  4182  // Right has already been evaluated to ssa, left has not.
  4183  // If deref is true, then we do left = *right instead (and right has already been nil-checked).
  4184  // If deref is true and right == nil, just do left = 0.
  4185  // skip indicates assignments (at the top level) that can be avoided.
  4186  // mayOverlap indicates whether left&right might partially overlap in memory. Default is false.
  4187  func (s *state) assign(left ir.Node, right *ssa.Value, deref bool, skip skipMask) {
  4188  	s.assignWhichMayOverlap(left, right, deref, skip, false)
  4189  }
  4190  func (s *state) assignWhichMayOverlap(left ir.Node, right *ssa.Value, deref bool, skip skipMask, mayOverlap bool) {
  4191  	if left.Op() == ir.ONAME && ir.IsBlank(left) {
  4192  		return
  4193  	}
  4194  	t := left.Type()
  4195  	types.CalcSize(t)
  4196  	if s.canSSA(left) {
  4197  		if deref {
  4198  			s.Fatalf("can SSA LHS %v but not RHS %s", left, right)
  4199  		}
  4200  		if left.Op() == ir.ODOT {
  4201  			// We're assigning to a field of an ssa-able value.
  4202  			// We need to build a new structure with the new value for the
  4203  			// field we're assigning and the old values for the other fields.
  4204  			// For instance:
  4205  			//   type T struct {a, b, c int}
  4206  			//   var T x
  4207  			//   x.b = 5
  4208  			// For the x.b = 5 assignment we want to generate x = T{x.a, 5, x.c}
  4209  
  4210  			// Grab information about the structure type.
  4211  			left := left.(*ir.SelectorExpr)
  4212  			t := left.X.Type()
  4213  			nf := t.NumFields()
  4214  			idx := fieldIdx(left)
  4215  
  4216  			// Grab old value of structure.
  4217  			old := s.expr(left.X)
  4218  
  4219  			// Make new structure.
  4220  			new := s.newValue0(ssa.OpStructMake, t)
  4221  
  4222  			// Add fields as args.
  4223  			for i := 0; i < nf; i++ {
  4224  				if i == idx {
  4225  					new.AddArg(right)
  4226  				} else {
  4227  					new.AddArg(s.newValue1I(ssa.OpStructSelect, t.FieldType(i), int64(i), old))
  4228  				}
  4229  			}
  4230  
  4231  			// Recursively assign the new value we've made to the base of the dot op.
  4232  			s.assign(left.X, new, false, 0)
  4233  			// TODO: do we need to update named values here?
  4234  			return
  4235  		}
  4236  		if left.Op() == ir.OINDEX && left.(*ir.IndexExpr).X.Type().IsArray() {
  4237  			left := left.(*ir.IndexExpr)
  4238  			s.pushLine(left.Pos())
  4239  			defer s.popLine()
  4240  			// We're assigning to an element of an ssa-able array.
  4241  			// a[i] = v
  4242  			t := left.X.Type()
  4243  			n := t.NumElem()
  4244  
  4245  			i := s.expr(left.Index) // index
  4246  			if n == 0 {
  4247  				// The bounds check must fail.  Might as well
  4248  				// ignore the actual index and just use zeros.
  4249  				z := s.constInt(types.Types[types.TINT], 0)
  4250  				s.boundsCheck(z, z, ssa.BoundsIndex, false)
  4251  				return
  4252  			}
  4253  			if n != 1 {
  4254  				s.Fatalf("assigning to non-1-length array")
  4255  			}
  4256  			// Rewrite to a = [1]{v}
  4257  			len := s.constInt(types.Types[types.TINT], 1)
  4258  			s.boundsCheck(i, len, ssa.BoundsIndex, false) // checks i == 0
  4259  			v := s.newValue1(ssa.OpArrayMake1, t, right)
  4260  			s.assign(left.X, v, false, 0)
  4261  			return
  4262  		}
  4263  		left := left.(*ir.Name)
  4264  		// Update variable assignment.
  4265  		s.vars[left] = right
  4266  		s.addNamedValue(left, right)
  4267  		return
  4268  	}
  4269  
  4270  	// If this assignment clobbers an entire local variable, then emit
  4271  	// OpVarDef so liveness analysis knows the variable is redefined.
  4272  	if base, ok := clobberBase(left).(*ir.Name); ok && base.OnStack() && skip == 0 && (t.HasPointers() || ssa.IsMergeCandidate(base)) {
  4273  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, base, s.mem(), !ir.IsAutoTmp(base))
  4274  	}
  4275  
  4276  	// Left is not ssa-able. Compute its address.
  4277  	addr := s.addr(left)
  4278  	if ir.IsReflectHeaderDataField(left) {
  4279  		// Package unsafe's documentation says storing pointers into
  4280  		// reflect.SliceHeader and reflect.StringHeader's Data fields
  4281  		// is valid, even though they have type uintptr (#19168).
  4282  		// Mark it pointer type to signal the writebarrier pass to
  4283  		// insert a write barrier.
  4284  		t = types.Types[types.TUNSAFEPTR]
  4285  	}
  4286  	if deref {
  4287  		// Treat as a mem->mem move.
  4288  		if right == nil {
  4289  			s.zero(t, addr)
  4290  		} else {
  4291  			s.moveWhichMayOverlap(t, addr, right, mayOverlap)
  4292  		}
  4293  		return
  4294  	}
  4295  	// Treat as a store.
  4296  	s.storeType(t, addr, right, skip, !ir.IsAutoTmp(left))
  4297  }
  4298  
  4299  // zeroVal returns the zero value for type t.
  4300  func (s *state) zeroVal(t *types.Type) *ssa.Value {
  4301  	switch {
  4302  	case t.IsInteger():
  4303  		switch t.Size() {
  4304  		case 1:
  4305  			return s.constInt8(t, 0)
  4306  		case 2:
  4307  			return s.constInt16(t, 0)
  4308  		case 4:
  4309  			return s.constInt32(t, 0)
  4310  		case 8:
  4311  			return s.constInt64(t, 0)
  4312  		default:
  4313  			s.Fatalf("bad sized integer type %v", t)
  4314  		}
  4315  	case t.IsFloat():
  4316  		switch t.Size() {
  4317  		case 4:
  4318  			return s.constFloat32(t, 0)
  4319  		case 8:
  4320  			return s.constFloat64(t, 0)
  4321  		default:
  4322  			s.Fatalf("bad sized float type %v", t)
  4323  		}
  4324  	case t.IsComplex():
  4325  		switch t.Size() {
  4326  		case 8:
  4327  			z := s.constFloat32(types.Types[types.TFLOAT32], 0)
  4328  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4329  		case 16:
  4330  			z := s.constFloat64(types.Types[types.TFLOAT64], 0)
  4331  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4332  		default:
  4333  			s.Fatalf("bad sized complex type %v", t)
  4334  		}
  4335  
  4336  	case t.IsString():
  4337  		return s.constEmptyString(t)
  4338  	case t.IsPtrShaped():
  4339  		return s.constNil(t)
  4340  	case t.IsBoolean():
  4341  		return s.constBool(false)
  4342  	case t.IsInterface():
  4343  		return s.constInterface(t)
  4344  	case t.IsSlice():
  4345  		return s.constSlice(t)
  4346  	case t.IsStruct():
  4347  		n := t.NumFields()
  4348  		v := s.entryNewValue0(ssa.OpStructMake, t)
  4349  		for i := 0; i < n; i++ {
  4350  			v.AddArg(s.zeroVal(t.FieldType(i)))
  4351  		}
  4352  		return v
  4353  	case t.IsArray():
  4354  		switch t.NumElem() {
  4355  		case 0:
  4356  			return s.entryNewValue0(ssa.OpArrayMake0, t)
  4357  		case 1:
  4358  			return s.entryNewValue1(ssa.OpArrayMake1, t, s.zeroVal(t.Elem()))
  4359  		}
  4360  	}
  4361  	s.Fatalf("zero for type %v not implemented", t)
  4362  	return nil
  4363  }
  4364  
  4365  type callKind int8
  4366  
  4367  const (
  4368  	callNormal callKind = iota
  4369  	callDefer
  4370  	callDeferStack
  4371  	callGo
  4372  	callTail
  4373  )
  4374  
  4375  type sfRtCallDef struct {
  4376  	rtfn  *obj.LSym
  4377  	rtype types.Kind
  4378  }
  4379  
  4380  var softFloatOps map[ssa.Op]sfRtCallDef
  4381  
  4382  func softfloatInit() {
  4383  	// Some of these operations get transformed by sfcall.
  4384  	softFloatOps = map[ssa.Op]sfRtCallDef{
  4385  		ssa.OpAdd32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4386  		ssa.OpAdd64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4387  		ssa.OpSub32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4388  		ssa.OpSub64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4389  		ssa.OpMul32F: {typecheck.LookupRuntimeFunc("fmul32"), types.TFLOAT32},
  4390  		ssa.OpMul64F: {typecheck.LookupRuntimeFunc("fmul64"), types.TFLOAT64},
  4391  		ssa.OpDiv32F: {typecheck.LookupRuntimeFunc("fdiv32"), types.TFLOAT32},
  4392  		ssa.OpDiv64F: {typecheck.LookupRuntimeFunc("fdiv64"), types.TFLOAT64},
  4393  
  4394  		ssa.OpEq64F:   {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4395  		ssa.OpEq32F:   {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4396  		ssa.OpNeq64F:  {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4397  		ssa.OpNeq32F:  {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4398  		ssa.OpLess64F: {typecheck.LookupRuntimeFunc("fgt64"), types.TBOOL},
  4399  		ssa.OpLess32F: {typecheck.LookupRuntimeFunc("fgt32"), types.TBOOL},
  4400  		ssa.OpLeq64F:  {typecheck.LookupRuntimeFunc("fge64"), types.TBOOL},
  4401  		ssa.OpLeq32F:  {typecheck.LookupRuntimeFunc("fge32"), types.TBOOL},
  4402  
  4403  		ssa.OpCvt32to32F:  {typecheck.LookupRuntimeFunc("fint32to32"), types.TFLOAT32},
  4404  		ssa.OpCvt32Fto32:  {typecheck.LookupRuntimeFunc("f32toint32"), types.TINT32},
  4405  		ssa.OpCvt64to32F:  {typecheck.LookupRuntimeFunc("fint64to32"), types.TFLOAT32},
  4406  		ssa.OpCvt32Fto64:  {typecheck.LookupRuntimeFunc("f32toint64"), types.TINT64},
  4407  		ssa.OpCvt64Uto32F: {typecheck.LookupRuntimeFunc("fuint64to32"), types.TFLOAT32},
  4408  		ssa.OpCvt32Fto64U: {typecheck.LookupRuntimeFunc("f32touint64"), types.TUINT64},
  4409  		ssa.OpCvt32to64F:  {typecheck.LookupRuntimeFunc("fint32to64"), types.TFLOAT64},
  4410  		ssa.OpCvt64Fto32:  {typecheck.LookupRuntimeFunc("f64toint32"), types.TINT32},
  4411  		ssa.OpCvt64to64F:  {typecheck.LookupRuntimeFunc("fint64to64"), types.TFLOAT64},
  4412  		ssa.OpCvt64Fto64:  {typecheck.LookupRuntimeFunc("f64toint64"), types.TINT64},
  4413  		ssa.OpCvt64Uto64F: {typecheck.LookupRuntimeFunc("fuint64to64"), types.TFLOAT64},
  4414  		ssa.OpCvt64Fto64U: {typecheck.LookupRuntimeFunc("f64touint64"), types.TUINT64},
  4415  		ssa.OpCvt32Fto64F: {typecheck.LookupRuntimeFunc("f32to64"), types.TFLOAT64},
  4416  		ssa.OpCvt64Fto32F: {typecheck.LookupRuntimeFunc("f64to32"), types.TFLOAT32},
  4417  	}
  4418  }
  4419  
  4420  // TODO: do not emit sfcall if operation can be optimized to constant in later
  4421  // opt phase
  4422  func (s *state) sfcall(op ssa.Op, args ...*ssa.Value) (*ssa.Value, bool) {
  4423  	f2i := func(t *types.Type) *types.Type {
  4424  		switch t.Kind() {
  4425  		case types.TFLOAT32:
  4426  			return types.Types[types.TUINT32]
  4427  		case types.TFLOAT64:
  4428  			return types.Types[types.TUINT64]
  4429  		}
  4430  		return t
  4431  	}
  4432  
  4433  	if callDef, ok := softFloatOps[op]; ok {
  4434  		switch op {
  4435  		case ssa.OpLess32F,
  4436  			ssa.OpLess64F,
  4437  			ssa.OpLeq32F,
  4438  			ssa.OpLeq64F:
  4439  			args[0], args[1] = args[1], args[0]
  4440  		case ssa.OpSub32F,
  4441  			ssa.OpSub64F:
  4442  			args[1] = s.newValue1(s.ssaOp(ir.ONEG, types.Types[callDef.rtype]), args[1].Type, args[1])
  4443  		}
  4444  
  4445  		// runtime functions take uints for floats and returns uints.
  4446  		// Convert to uints so we use the right calling convention.
  4447  		for i, a := range args {
  4448  			if a.Type.IsFloat() {
  4449  				args[i] = s.newValue1(ssa.OpCopy, f2i(a.Type), a)
  4450  			}
  4451  		}
  4452  
  4453  		rt := types.Types[callDef.rtype]
  4454  		result := s.rtcall(callDef.rtfn, true, []*types.Type{f2i(rt)}, args...)[0]
  4455  		if rt.IsFloat() {
  4456  			result = s.newValue1(ssa.OpCopy, rt, result)
  4457  		}
  4458  		if op == ssa.OpNeq32F || op == ssa.OpNeq64F {
  4459  			result = s.newValue1(ssa.OpNot, result.Type, result)
  4460  		}
  4461  		return result, true
  4462  	}
  4463  	return nil, false
  4464  }
  4465  
  4466  // split breaks up a tuple-typed value into its 2 parts.
  4467  func (s *state) split(v *ssa.Value) (*ssa.Value, *ssa.Value) {
  4468  	p0 := s.newValue1(ssa.OpSelect0, v.Type.FieldType(0), v)
  4469  	p1 := s.newValue1(ssa.OpSelect1, v.Type.FieldType(1), v)
  4470  	return p0, p1
  4471  }
  4472  
  4473  // intrinsicCall converts a call to a recognized intrinsic function into the intrinsic SSA operation.
  4474  func (s *state) intrinsicCall(n *ir.CallExpr) *ssa.Value {
  4475  	v := findIntrinsic(n.Fun.Sym())(s, n, s.intrinsicArgs(n))
  4476  	if ssa.IntrinsicsDebug > 0 {
  4477  		x := v
  4478  		if x == nil {
  4479  			x = s.mem()
  4480  		}
  4481  		if x.Op == ssa.OpSelect0 || x.Op == ssa.OpSelect1 {
  4482  			x = x.Args[0]
  4483  		}
  4484  		base.WarnfAt(n.Pos(), "intrinsic substitution for %v with %s", n.Fun.Sym().Name, x.LongString())
  4485  	}
  4486  	return v
  4487  }
  4488  
  4489  // intrinsicArgs extracts args from n, evaluates them to SSA values, and returns them.
  4490  func (s *state) intrinsicArgs(n *ir.CallExpr) []*ssa.Value {
  4491  	args := make([]*ssa.Value, len(n.Args))
  4492  	for i, n := range n.Args {
  4493  		args[i] = s.expr(n)
  4494  	}
  4495  	return args
  4496  }
  4497  
  4498  // openDeferRecord adds code to evaluate and store the function for an open-code defer
  4499  // call, and records info about the defer, so we can generate proper code on the
  4500  // exit paths. n is the sub-node of the defer node that is the actual function
  4501  // call. We will also record funcdata information on where the function is stored
  4502  // (as well as the deferBits variable), and this will enable us to run the proper
  4503  // defer calls during panics.
  4504  func (s *state) openDeferRecord(n *ir.CallExpr) {
  4505  	if len(n.Args) != 0 || n.Op() != ir.OCALLFUNC || n.Fun.Type().NumResults() != 0 {
  4506  		s.Fatalf("defer call with arguments or results: %v", n)
  4507  	}
  4508  
  4509  	opendefer := &openDeferInfo{
  4510  		n: n,
  4511  	}
  4512  	fn := n.Fun
  4513  	// We must always store the function value in a stack slot for the
  4514  	// runtime panic code to use. But in the defer exit code, we will
  4515  	// call the function directly if it is a static function.
  4516  	closureVal := s.expr(fn)
  4517  	closure := s.openDeferSave(fn.Type(), closureVal)
  4518  	opendefer.closureNode = closure.Aux.(*ir.Name)
  4519  	if !(fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC) {
  4520  		opendefer.closure = closure
  4521  	}
  4522  	index := len(s.openDefers)
  4523  	s.openDefers = append(s.openDefers, opendefer)
  4524  
  4525  	// Update deferBits only after evaluation and storage to stack of
  4526  	// the function is successful.
  4527  	bitvalue := s.constInt8(types.Types[types.TUINT8], 1<<uint(index))
  4528  	newDeferBits := s.newValue2(ssa.OpOr8, types.Types[types.TUINT8], s.variable(deferBitsVar, types.Types[types.TUINT8]), bitvalue)
  4529  	s.vars[deferBitsVar] = newDeferBits
  4530  	s.store(types.Types[types.TUINT8], s.deferBitsAddr, newDeferBits)
  4531  }
  4532  
  4533  // openDeferSave generates SSA nodes to store a value (with type t) for an
  4534  // open-coded defer at an explicit autotmp location on the stack, so it can be
  4535  // reloaded and used for the appropriate call on exit. Type t must be a function type
  4536  // (therefore SSAable). val is the value to be stored. The function returns an SSA
  4537  // value representing a pointer to the autotmp location.
  4538  func (s *state) openDeferSave(t *types.Type, val *ssa.Value) *ssa.Value {
  4539  	if !ssa.CanSSA(t) {
  4540  		s.Fatalf("openDeferSave of non-SSA-able type %v val=%v", t, val)
  4541  	}
  4542  	if !t.HasPointers() {
  4543  		s.Fatalf("openDeferSave of pointerless type %v val=%v", t, val)
  4544  	}
  4545  	pos := val.Pos
  4546  	temp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
  4547  	temp.SetOpenDeferSlot(true)
  4548  	temp.SetFrameOffset(int64(len(s.openDefers))) // so cmpstackvarlt can order them
  4549  	var addrTemp *ssa.Value
  4550  	// Use OpVarLive to make sure stack slot for the closure is not removed by
  4551  	// dead-store elimination
  4552  	if s.curBlock.ID != s.f.Entry.ID {
  4553  		// Force the tmp storing this defer function to be declared in the entry
  4554  		// block, so that it will be live for the defer exit code (which will
  4555  		// actually access it only if the associated defer call has been activated).
  4556  		if t.HasPointers() {
  4557  			s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarDef, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4558  		}
  4559  		s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarLive, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4560  		addrTemp = s.f.Entry.NewValue2A(src.NoXPos, ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.defvars[s.f.Entry.ID][memVar])
  4561  	} else {
  4562  		// Special case if we're still in the entry block. We can't use
  4563  		// the above code, since s.defvars[s.f.Entry.ID] isn't defined
  4564  		// until we end the entry block with s.endBlock().
  4565  		if t.HasPointers() {
  4566  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, temp, s.mem(), false)
  4567  		}
  4568  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, temp, s.mem(), false)
  4569  		addrTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.mem(), false)
  4570  	}
  4571  	// Since we may use this temp during exit depending on the
  4572  	// deferBits, we must define it unconditionally on entry.
  4573  	// Therefore, we must make sure it is zeroed out in the entry
  4574  	// block if it contains pointers, else GC may wrongly follow an
  4575  	// uninitialized pointer value.
  4576  	temp.SetNeedzero(true)
  4577  	// We are storing to the stack, hence we can avoid the full checks in
  4578  	// storeType() (no write barrier) and do a simple store().
  4579  	s.store(t, addrTemp, val)
  4580  	return addrTemp
  4581  }
  4582  
  4583  // openDeferExit generates SSA for processing all the open coded defers at exit.
  4584  // The code involves loading deferBits, and checking each of the bits to see if
  4585  // the corresponding defer statement was executed. For each bit that is turned
  4586  // on, the associated defer call is made.
  4587  func (s *state) openDeferExit() {
  4588  	deferExit := s.f.NewBlock(ssa.BlockPlain)
  4589  	s.endBlock().AddEdgeTo(deferExit)
  4590  	s.startBlock(deferExit)
  4591  	s.lastDeferExit = deferExit
  4592  	s.lastDeferCount = len(s.openDefers)
  4593  	zeroval := s.constInt8(types.Types[types.TUINT8], 0)
  4594  	// Test for and run defers in reverse order
  4595  	for i := len(s.openDefers) - 1; i >= 0; i-- {
  4596  		r := s.openDefers[i]
  4597  		bCond := s.f.NewBlock(ssa.BlockPlain)
  4598  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  4599  
  4600  		deferBits := s.variable(deferBitsVar, types.Types[types.TUINT8])
  4601  		// Generate code to check if the bit associated with the current
  4602  		// defer is set.
  4603  		bitval := s.constInt8(types.Types[types.TUINT8], 1<<uint(i))
  4604  		andval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, bitval)
  4605  		eqVal := s.newValue2(ssa.OpEq8, types.Types[types.TBOOL], andval, zeroval)
  4606  		b := s.endBlock()
  4607  		b.Kind = ssa.BlockIf
  4608  		b.SetControl(eqVal)
  4609  		b.AddEdgeTo(bEnd)
  4610  		b.AddEdgeTo(bCond)
  4611  		bCond.AddEdgeTo(bEnd)
  4612  		s.startBlock(bCond)
  4613  
  4614  		// Clear this bit in deferBits and force store back to stack, so
  4615  		// we will not try to re-run this defer call if this defer call panics.
  4616  		nbitval := s.newValue1(ssa.OpCom8, types.Types[types.TUINT8], bitval)
  4617  		maskedval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, nbitval)
  4618  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, maskedval)
  4619  		// Use this value for following tests, so we keep previous
  4620  		// bits cleared.
  4621  		s.vars[deferBitsVar] = maskedval
  4622  
  4623  		// Generate code to call the function call of the defer, using the
  4624  		// closure that were stored in argtmps at the point of the defer
  4625  		// statement.
  4626  		fn := r.n.Fun
  4627  		stksize := fn.Type().ArgWidth()
  4628  		var callArgs []*ssa.Value
  4629  		var call *ssa.Value
  4630  		if r.closure != nil {
  4631  			v := s.load(r.closure.Type.Elem(), r.closure)
  4632  			s.maybeNilCheckClosure(v, callDefer)
  4633  			codeptr := s.rawLoad(types.Types[types.TUINTPTR], v)
  4634  			aux := ssa.ClosureAuxCall(s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  4635  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, v)
  4636  		} else {
  4637  			aux := ssa.StaticAuxCall(fn.(*ir.Name).Linksym(), s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  4638  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  4639  		}
  4640  		callArgs = append(callArgs, s.mem())
  4641  		call.AddArgs(callArgs...)
  4642  		call.AuxInt = stksize
  4643  		s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, 0, call)
  4644  		// Make sure that the stack slots with pointers are kept live
  4645  		// through the call (which is a pre-emption point). Also, we will
  4646  		// use the first call of the last defer exit to compute liveness
  4647  		// for the deferreturn, so we want all stack slots to be live.
  4648  		if r.closureNode != nil {
  4649  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, r.closureNode, s.mem(), false)
  4650  		}
  4651  
  4652  		s.endBlock()
  4653  		s.startBlock(bEnd)
  4654  	}
  4655  }
  4656  
  4657  func (s *state) callResult(n *ir.CallExpr, k callKind) *ssa.Value {
  4658  	return s.call(n, k, false, nil)
  4659  }
  4660  
  4661  func (s *state) callAddr(n *ir.CallExpr, k callKind) *ssa.Value {
  4662  	return s.call(n, k, true, nil)
  4663  }
  4664  
  4665  // Calls the function n using the specified call type.
  4666  // Returns the address of the return value (or nil if none).
  4667  func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool, deferExtra ir.Expr) *ssa.Value {
  4668  	s.prevCall = nil
  4669  	var calleeLSym *obj.LSym // target function (if static)
  4670  	var closure *ssa.Value   // ptr to closure to run (if dynamic)
  4671  	var codeptr *ssa.Value   // ptr to target code (if dynamic)
  4672  	var dextra *ssa.Value    // defer extra arg
  4673  	var rcvr *ssa.Value      // receiver to set
  4674  	fn := n.Fun
  4675  	var ACArgs []*types.Type    // AuxCall args
  4676  	var ACResults []*types.Type // AuxCall results
  4677  	var callArgs []*ssa.Value   // For late-expansion, the args themselves (not stored, args to the call instead).
  4678  
  4679  	callABI := s.f.ABIDefault
  4680  
  4681  	if k != callNormal && k != callTail && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.Fun.Type().NumResults() != 0) {
  4682  		s.Fatalf("go/defer call with arguments: %v", n)
  4683  	}
  4684  
  4685  	isCallDeferRangeFunc := false
  4686  
  4687  	switch n.Op() {
  4688  	case ir.OCALLFUNC:
  4689  		if (k == callNormal || k == callTail) && fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC {
  4690  			fn := fn.(*ir.Name)
  4691  			calleeLSym = callTargetLSym(fn)
  4692  			if buildcfg.Experiment.RegabiArgs {
  4693  				// This is a static call, so it may be
  4694  				// a direct call to a non-ABIInternal
  4695  				// function. fn.Func may be nil for
  4696  				// some compiler-generated functions,
  4697  				// but those are all ABIInternal.
  4698  				if fn.Func != nil {
  4699  					callABI = abiForFunc(fn.Func, s.f.ABI0, s.f.ABI1)
  4700  				}
  4701  			} else {
  4702  				// TODO(register args) remove after register abi is working
  4703  				inRegistersImported := fn.Pragma()&ir.RegisterParams != 0
  4704  				inRegistersSamePackage := fn.Func != nil && fn.Func.Pragma&ir.RegisterParams != 0
  4705  				if inRegistersImported || inRegistersSamePackage {
  4706  					callABI = s.f.ABI1
  4707  				}
  4708  			}
  4709  			if fn := n.Fun.Sym().Name; n.Fun.Sym().Pkg == ir.Pkgs.Runtime && fn == "deferrangefunc" {
  4710  				isCallDeferRangeFunc = true
  4711  			}
  4712  			break
  4713  		}
  4714  		closure = s.expr(fn)
  4715  		if k != callDefer && k != callDeferStack {
  4716  			// Deferred nil function needs to panic when the function is invoked,
  4717  			// not the point of defer statement.
  4718  			s.maybeNilCheckClosure(closure, k)
  4719  		}
  4720  	case ir.OCALLINTER:
  4721  		if fn.Op() != ir.ODOTINTER {
  4722  			s.Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op())
  4723  		}
  4724  		fn := fn.(*ir.SelectorExpr)
  4725  		var iclosure *ssa.Value
  4726  		iclosure, rcvr = s.getClosureAndRcvr(fn)
  4727  		if k == callNormal {
  4728  			codeptr = s.load(types.Types[types.TUINTPTR], iclosure)
  4729  		} else {
  4730  			closure = iclosure
  4731  		}
  4732  	}
  4733  	if deferExtra != nil {
  4734  		dextra = s.expr(deferExtra)
  4735  	}
  4736  
  4737  	params := callABI.ABIAnalyze(n.Fun.Type(), false /* Do not set (register) nNames from caller side -- can cause races. */)
  4738  	types.CalcSize(fn.Type())
  4739  	stksize := params.ArgWidth() // includes receiver, args, and results
  4740  
  4741  	res := n.Fun.Type().Results()
  4742  	if k == callNormal || k == callTail {
  4743  		for _, p := range params.OutParams() {
  4744  			ACResults = append(ACResults, p.Type)
  4745  		}
  4746  	}
  4747  
  4748  	var call *ssa.Value
  4749  	if k == callDeferStack {
  4750  		if stksize != 0 {
  4751  			s.Fatalf("deferprocStack with non-zero stack size %d: %v", stksize, n)
  4752  		}
  4753  		// Make a defer struct on the stack.
  4754  		t := deferstruct()
  4755  		n, addr := s.temp(n.Pos(), t)
  4756  		n.SetNonMergeable(true)
  4757  		s.store(closure.Type,
  4758  			s.newValue1I(ssa.OpOffPtr, closure.Type.PtrTo(), t.FieldOff(deferStructFnField), addr),
  4759  			closure)
  4760  
  4761  		// Call runtime.deferprocStack with pointer to _defer record.
  4762  		ACArgs = append(ACArgs, types.Types[types.TUINTPTR])
  4763  		aux := ssa.StaticAuxCall(ir.Syms.DeferprocStack, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  4764  		callArgs = append(callArgs, addr, s.mem())
  4765  		call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  4766  		call.AddArgs(callArgs...)
  4767  		call.AuxInt = int64(types.PtrSize) // deferprocStack takes a *_defer arg
  4768  	} else {
  4769  		// Store arguments to stack, including defer/go arguments and receiver for method calls.
  4770  		// These are written in SP-offset order.
  4771  		argStart := base.Ctxt.Arch.FixedFrameSize
  4772  		// Defer/go args.
  4773  		if k != callNormal && k != callTail {
  4774  			// Write closure (arg to newproc/deferproc).
  4775  			ACArgs = append(ACArgs, types.Types[types.TUINTPTR]) // not argExtra
  4776  			callArgs = append(callArgs, closure)
  4777  			stksize += int64(types.PtrSize)
  4778  			argStart += int64(types.PtrSize)
  4779  			if dextra != nil {
  4780  				// Extra token of type any for deferproc
  4781  				ACArgs = append(ACArgs, types.Types[types.TINTER])
  4782  				callArgs = append(callArgs, dextra)
  4783  				stksize += 2 * int64(types.PtrSize)
  4784  				argStart += 2 * int64(types.PtrSize)
  4785  			}
  4786  		}
  4787  
  4788  		// Set receiver (for interface calls).
  4789  		if rcvr != nil {
  4790  			callArgs = append(callArgs, rcvr)
  4791  		}
  4792  
  4793  		// Write args.
  4794  		t := n.Fun.Type()
  4795  		args := n.Args
  4796  
  4797  		for _, p := range params.InParams() { // includes receiver for interface calls
  4798  			ACArgs = append(ACArgs, p.Type)
  4799  		}
  4800  
  4801  		// Split the entry block if there are open defers, because later calls to
  4802  		// openDeferSave may cause a mismatch between the mem for an OpDereference
  4803  		// and the call site which uses it. See #49282.
  4804  		if s.curBlock.ID == s.f.Entry.ID && s.hasOpenDefers {
  4805  			b := s.endBlock()
  4806  			b.Kind = ssa.BlockPlain
  4807  			curb := s.f.NewBlock(ssa.BlockPlain)
  4808  			b.AddEdgeTo(curb)
  4809  			s.startBlock(curb)
  4810  		}
  4811  
  4812  		for i, n := range args {
  4813  			callArgs = append(callArgs, s.putArg(n, t.Param(i).Type))
  4814  		}
  4815  
  4816  		callArgs = append(callArgs, s.mem())
  4817  
  4818  		// call target
  4819  		switch {
  4820  		case k == callDefer:
  4821  			sym := ir.Syms.Deferproc
  4822  			if dextra != nil {
  4823  				sym = ir.Syms.Deferprocat
  4824  			}
  4825  			aux := ssa.StaticAuxCall(sym, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults)) // TODO paramResultInfo for Deferproc(at)
  4826  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  4827  		case k == callGo:
  4828  			aux := ssa.StaticAuxCall(ir.Syms.Newproc, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  4829  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux) // TODO paramResultInfo for Newproc
  4830  		case closure != nil:
  4831  			// rawLoad because loading the code pointer from a
  4832  			// closure is always safe, but IsSanitizerSafeAddr
  4833  			// can't always figure that out currently, and it's
  4834  			// critical that we not clobber any arguments already
  4835  			// stored onto the stack.
  4836  			codeptr = s.rawLoad(types.Types[types.TUINTPTR], closure)
  4837  			aux := ssa.ClosureAuxCall(callABI.ABIAnalyzeTypes(ACArgs, ACResults))
  4838  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, closure)
  4839  		case codeptr != nil:
  4840  			// Note that the "receiver" parameter is nil because the actual receiver is the first input parameter.
  4841  			aux := ssa.InterfaceAuxCall(params)
  4842  			call = s.newValue1A(ssa.OpInterLECall, aux.LateExpansionResultType(), aux, codeptr)
  4843  		case calleeLSym != nil:
  4844  			aux := ssa.StaticAuxCall(calleeLSym, params)
  4845  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  4846  			if k == callTail {
  4847  				call.Op = ssa.OpTailLECall
  4848  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  4849  			}
  4850  		default:
  4851  			s.Fatalf("bad call type %v %v", n.Op(), n)
  4852  		}
  4853  		call.AddArgs(callArgs...)
  4854  		call.AuxInt = stksize // Call operations carry the argsize of the callee along with them
  4855  	}
  4856  	s.prevCall = call
  4857  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(ACResults)), call)
  4858  	// Insert VarLive opcodes.
  4859  	for _, v := range n.KeepAlive {
  4860  		if !v.Addrtaken() {
  4861  			s.Fatalf("KeepAlive variable %v must have Addrtaken set", v)
  4862  		}
  4863  		switch v.Class {
  4864  		case ir.PAUTO, ir.PPARAM, ir.PPARAMOUT:
  4865  		default:
  4866  			s.Fatalf("KeepAlive variable %v must be Auto or Arg", v)
  4867  		}
  4868  		s.vars[memVar] = s.newValue1A(ssa.OpVarLive, types.TypeMem, v, s.mem())
  4869  	}
  4870  
  4871  	// Finish block for defers
  4872  	if k == callDefer || k == callDeferStack || isCallDeferRangeFunc {
  4873  		b := s.endBlock()
  4874  		b.Kind = ssa.BlockDefer
  4875  		b.SetControl(call)
  4876  		bNext := s.f.NewBlock(ssa.BlockPlain)
  4877  		b.AddEdgeTo(bNext)
  4878  		r := s.f.DeferReturn // Share a single deferreturn among all defers
  4879  		if r == nil {
  4880  			r = s.f.NewBlock(ssa.BlockPlain)
  4881  			s.startBlock(r)
  4882  			s.exit()
  4883  			s.f.DeferReturn = r
  4884  		}
  4885  		b.AddEdgeTo(r) // Add recover edge to exit code.  This is a fake edge to keep the block live.
  4886  		b.Likely = ssa.BranchLikely
  4887  		s.startBlock(bNext)
  4888  	}
  4889  
  4890  	if len(res) == 0 || k != callNormal {
  4891  		// call has no return value. Continue with the next statement.
  4892  		return nil
  4893  	}
  4894  	fp := res[0]
  4895  	if returnResultAddr {
  4896  		return s.resultAddrOfCall(call, 0, fp.Type)
  4897  	}
  4898  	return s.newValue1I(ssa.OpSelectN, fp.Type, 0, call)
  4899  }
  4900  
  4901  // maybeNilCheckClosure checks if a nil check of a closure is needed in some
  4902  // architecture-dependent situations and, if so, emits the nil check.
  4903  func (s *state) maybeNilCheckClosure(closure *ssa.Value, k callKind) {
  4904  	if Arch.LinkArch.Family == sys.Wasm || buildcfg.GOOS == "aix" && k != callGo {
  4905  		// On AIX, the closure needs to be verified as fn can be nil, except if it's a call go. This needs to be handled by the runtime to have the "go of nil func value" error.
  4906  		// TODO(neelance): On other architectures this should be eliminated by the optimization steps
  4907  		s.nilCheck(closure)
  4908  	}
  4909  }
  4910  
  4911  // getClosureAndRcvr returns values for the appropriate closure and receiver of an
  4912  // interface call
  4913  func (s *state) getClosureAndRcvr(fn *ir.SelectorExpr) (*ssa.Value, *ssa.Value) {
  4914  	i := s.expr(fn.X)
  4915  	itab := s.newValue1(ssa.OpITab, types.Types[types.TUINTPTR], i)
  4916  	s.nilCheck(itab)
  4917  	itabidx := fn.Offset() + rttype.ITab.OffsetOf("Fun")
  4918  	closure := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.UintptrPtr, itabidx, itab)
  4919  	rcvr := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, i)
  4920  	return closure, rcvr
  4921  }
  4922  
  4923  // etypesign returns the signed-ness of e, for integer/pointer etypes.
  4924  // -1 means signed, +1 means unsigned, 0 means non-integer/non-pointer.
  4925  func etypesign(e types.Kind) int8 {
  4926  	switch e {
  4927  	case types.TINT8, types.TINT16, types.TINT32, types.TINT64, types.TINT:
  4928  		return -1
  4929  	case types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64, types.TUINT, types.TUINTPTR, types.TUNSAFEPTR:
  4930  		return +1
  4931  	}
  4932  	return 0
  4933  }
  4934  
  4935  // addr converts the address of the expression n to SSA, adds it to s and returns the SSA result.
  4936  // The value that the returned Value represents is guaranteed to be non-nil.
  4937  func (s *state) addr(n ir.Node) *ssa.Value {
  4938  	if n.Op() != ir.ONAME {
  4939  		s.pushLine(n.Pos())
  4940  		defer s.popLine()
  4941  	}
  4942  
  4943  	if s.canSSA(n) {
  4944  		s.Fatalf("addr of canSSA expression: %+v", n)
  4945  	}
  4946  
  4947  	t := types.NewPtr(n.Type())
  4948  	linksymOffset := func(lsym *obj.LSym, offset int64) *ssa.Value {
  4949  		v := s.entryNewValue1A(ssa.OpAddr, t, lsym, s.sb)
  4950  		// TODO: Make OpAddr use AuxInt as well as Aux.
  4951  		if offset != 0 {
  4952  			v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, offset, v)
  4953  		}
  4954  		return v
  4955  	}
  4956  	switch n.Op() {
  4957  	case ir.OLINKSYMOFFSET:
  4958  		no := n.(*ir.LinksymOffsetExpr)
  4959  		return linksymOffset(no.Linksym, no.Offset_)
  4960  	case ir.ONAME:
  4961  		n := n.(*ir.Name)
  4962  		if n.Heapaddr != nil {
  4963  			return s.expr(n.Heapaddr)
  4964  		}
  4965  		switch n.Class {
  4966  		case ir.PEXTERN:
  4967  			// global variable
  4968  			return linksymOffset(n.Linksym(), 0)
  4969  		case ir.PPARAM:
  4970  			// parameter slot
  4971  			v := s.decladdrs[n]
  4972  			if v != nil {
  4973  				return v
  4974  			}
  4975  			s.Fatalf("addr of undeclared ONAME %v. declared: %v", n, s.decladdrs)
  4976  			return nil
  4977  		case ir.PAUTO:
  4978  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), !ir.IsAutoTmp(n))
  4979  
  4980  		case ir.PPARAMOUT: // Same as PAUTO -- cannot generate LEA early.
  4981  			// ensure that we reuse symbols for out parameters so
  4982  			// that cse works on their addresses
  4983  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), true)
  4984  		default:
  4985  			s.Fatalf("variable address class %v not implemented", n.Class)
  4986  			return nil
  4987  		}
  4988  	case ir.ORESULT:
  4989  		// load return from callee
  4990  		n := n.(*ir.ResultExpr)
  4991  		return s.resultAddrOfCall(s.prevCall, n.Index, n.Type())
  4992  	case ir.OINDEX:
  4993  		n := n.(*ir.IndexExpr)
  4994  		if n.X.Type().IsSlice() {
  4995  			a := s.expr(n.X)
  4996  			i := s.expr(n.Index)
  4997  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], a)
  4998  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  4999  			p := s.newValue1(ssa.OpSlicePtr, t, a)
  5000  			return s.newValue2(ssa.OpPtrIndex, t, p, i)
  5001  		} else { // array
  5002  			a := s.addr(n.X)
  5003  			i := s.expr(n.Index)
  5004  			len := s.constInt(types.Types[types.TINT], n.X.Type().NumElem())
  5005  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5006  			return s.newValue2(ssa.OpPtrIndex, types.NewPtr(n.X.Type().Elem()), a, i)
  5007  		}
  5008  	case ir.ODEREF:
  5009  		n := n.(*ir.StarExpr)
  5010  		return s.exprPtr(n.X, n.Bounded(), n.Pos())
  5011  	case ir.ODOT:
  5012  		n := n.(*ir.SelectorExpr)
  5013  		p := s.addr(n.X)
  5014  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5015  	case ir.ODOTPTR:
  5016  		n := n.(*ir.SelectorExpr)
  5017  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  5018  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5019  	case ir.OCONVNOP:
  5020  		n := n.(*ir.ConvExpr)
  5021  		if n.Type() == n.X.Type() {
  5022  			return s.addr(n.X)
  5023  		}
  5024  		addr := s.addr(n.X)
  5025  		return s.newValue1(ssa.OpCopy, t, addr) // ensure that addr has the right type
  5026  	case ir.OCALLFUNC, ir.OCALLINTER:
  5027  		n := n.(*ir.CallExpr)
  5028  		return s.callAddr(n, callNormal)
  5029  	case ir.ODOTTYPE, ir.ODYNAMICDOTTYPE:
  5030  		var v *ssa.Value
  5031  		if n.Op() == ir.ODOTTYPE {
  5032  			v, _ = s.dottype(n.(*ir.TypeAssertExpr), false)
  5033  		} else {
  5034  			v, _ = s.dynamicDottype(n.(*ir.DynamicTypeAssertExpr), false)
  5035  		}
  5036  		if v.Op != ssa.OpLoad {
  5037  			s.Fatalf("dottype of non-load")
  5038  		}
  5039  		if v.Args[1] != s.mem() {
  5040  			s.Fatalf("memory no longer live from dottype load")
  5041  		}
  5042  		return v.Args[0]
  5043  	default:
  5044  		s.Fatalf("unhandled addr %v", n.Op())
  5045  		return nil
  5046  	}
  5047  }
  5048  
  5049  // canSSA reports whether n is SSA-able.
  5050  // n must be an ONAME (or an ODOT sequence with an ONAME base).
  5051  func (s *state) canSSA(n ir.Node) bool {
  5052  	if base.Flag.N != 0 {
  5053  		return false
  5054  	}
  5055  	for {
  5056  		nn := n
  5057  		if nn.Op() == ir.ODOT {
  5058  			nn := nn.(*ir.SelectorExpr)
  5059  			n = nn.X
  5060  			continue
  5061  		}
  5062  		if nn.Op() == ir.OINDEX {
  5063  			nn := nn.(*ir.IndexExpr)
  5064  			if nn.X.Type().IsArray() {
  5065  				n = nn.X
  5066  				continue
  5067  			}
  5068  		}
  5069  		break
  5070  	}
  5071  	if n.Op() != ir.ONAME {
  5072  		return false
  5073  	}
  5074  	return s.canSSAName(n.(*ir.Name)) && ssa.CanSSA(n.Type())
  5075  }
  5076  
  5077  func (s *state) canSSAName(name *ir.Name) bool {
  5078  	if name.Addrtaken() || !name.OnStack() {
  5079  		return false
  5080  	}
  5081  	switch name.Class {
  5082  	case ir.PPARAMOUT:
  5083  		if s.hasdefer {
  5084  			// TODO: handle this case? Named return values must be
  5085  			// in memory so that the deferred function can see them.
  5086  			// Maybe do: if !strings.HasPrefix(n.String(), "~") { return false }
  5087  			// Or maybe not, see issue 18860.  Even unnamed return values
  5088  			// must be written back so if a defer recovers, the caller can see them.
  5089  			return false
  5090  		}
  5091  		if s.cgoUnsafeArgs {
  5092  			// Cgo effectively takes the address of all result args,
  5093  			// but the compiler can't see that.
  5094  			return false
  5095  		}
  5096  	}
  5097  	return true
  5098  	// TODO: try to make more variables SSAable?
  5099  }
  5100  
  5101  // exprPtr evaluates n to a pointer and nil-checks it.
  5102  func (s *state) exprPtr(n ir.Node, bounded bool, lineno src.XPos) *ssa.Value {
  5103  	p := s.expr(n)
  5104  	if bounded || n.NonNil() {
  5105  		if s.f.Frontend().Debug_checknil() && lineno.Line() > 1 {
  5106  			s.f.Warnl(lineno, "removed nil check")
  5107  		}
  5108  		return p
  5109  	}
  5110  	p = s.nilCheck(p)
  5111  	return p
  5112  }
  5113  
  5114  // nilCheck generates nil pointer checking code.
  5115  // Used only for automatically inserted nil checks,
  5116  // not for user code like 'x != nil'.
  5117  // Returns a "definitely not nil" copy of x to ensure proper ordering
  5118  // of the uses of the post-nilcheck pointer.
  5119  func (s *state) nilCheck(ptr *ssa.Value) *ssa.Value {
  5120  	if base.Debug.DisableNil != 0 || s.curfn.NilCheckDisabled() {
  5121  		return ptr
  5122  	}
  5123  	return s.newValue2(ssa.OpNilCheck, ptr.Type, ptr, s.mem())
  5124  }
  5125  
  5126  // boundsCheck generates bounds checking code. Checks if 0 <= idx <[=] len, branches to exit if not.
  5127  // Starts a new block on return.
  5128  // On input, len must be converted to full int width and be nonnegative.
  5129  // Returns idx converted to full int width.
  5130  // If bounded is true then caller guarantees the index is not out of bounds
  5131  // (but boundsCheck will still extend the index to full int width).
  5132  func (s *state) boundsCheck(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  5133  	idx = s.extendIndex(idx, len, kind, bounded)
  5134  
  5135  	if bounded || base.Flag.B != 0 {
  5136  		// If bounded or bounds checking is flag-disabled, then no check necessary,
  5137  		// just return the extended index.
  5138  		//
  5139  		// Here, bounded == true if the compiler generated the index itself,
  5140  		// such as in the expansion of a slice initializer. These indexes are
  5141  		// compiler-generated, not Go program variables, so they cannot be
  5142  		// attacker-controlled, so we can omit Spectre masking as well.
  5143  		//
  5144  		// Note that we do not want to omit Spectre masking in code like:
  5145  		//
  5146  		//	if 0 <= i && i < len(x) {
  5147  		//		use(x[i])
  5148  		//	}
  5149  		//
  5150  		// Lucky for us, bounded==false for that code.
  5151  		// In that case (handled below), we emit a bound check (and Spectre mask)
  5152  		// and then the prove pass will remove the bounds check.
  5153  		// In theory the prove pass could potentially remove certain
  5154  		// Spectre masks, but it's very delicate and probably better
  5155  		// to be conservative and leave them all in.
  5156  		return idx
  5157  	}
  5158  
  5159  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5160  	bPanic := s.f.NewBlock(ssa.BlockExit)
  5161  
  5162  	if !idx.Type.IsSigned() {
  5163  		switch kind {
  5164  		case ssa.BoundsIndex:
  5165  			kind = ssa.BoundsIndexU
  5166  		case ssa.BoundsSliceAlen:
  5167  			kind = ssa.BoundsSliceAlenU
  5168  		case ssa.BoundsSliceAcap:
  5169  			kind = ssa.BoundsSliceAcapU
  5170  		case ssa.BoundsSliceB:
  5171  			kind = ssa.BoundsSliceBU
  5172  		case ssa.BoundsSlice3Alen:
  5173  			kind = ssa.BoundsSlice3AlenU
  5174  		case ssa.BoundsSlice3Acap:
  5175  			kind = ssa.BoundsSlice3AcapU
  5176  		case ssa.BoundsSlice3B:
  5177  			kind = ssa.BoundsSlice3BU
  5178  		case ssa.BoundsSlice3C:
  5179  			kind = ssa.BoundsSlice3CU
  5180  		}
  5181  	}
  5182  
  5183  	var cmp *ssa.Value
  5184  	if kind == ssa.BoundsIndex || kind == ssa.BoundsIndexU {
  5185  		cmp = s.newValue2(ssa.OpIsInBounds, types.Types[types.TBOOL], idx, len)
  5186  	} else {
  5187  		cmp = s.newValue2(ssa.OpIsSliceInBounds, types.Types[types.TBOOL], idx, len)
  5188  	}
  5189  	b := s.endBlock()
  5190  	b.Kind = ssa.BlockIf
  5191  	b.SetControl(cmp)
  5192  	b.Likely = ssa.BranchLikely
  5193  	b.AddEdgeTo(bNext)
  5194  	b.AddEdgeTo(bPanic)
  5195  
  5196  	s.startBlock(bPanic)
  5197  	if Arch.LinkArch.Family == sys.Wasm {
  5198  		// TODO(khr): figure out how to do "register" based calling convention for bounds checks.
  5199  		// Should be similar to gcWriteBarrier, but I can't make it work.
  5200  		s.rtcall(BoundsCheckFunc[kind], false, nil, idx, len)
  5201  	} else {
  5202  		mem := s.newValue3I(ssa.OpPanicBounds, types.TypeMem, int64(kind), idx, len, s.mem())
  5203  		s.endBlock().SetControl(mem)
  5204  	}
  5205  	s.startBlock(bNext)
  5206  
  5207  	// In Spectre index mode, apply an appropriate mask to avoid speculative out-of-bounds accesses.
  5208  	if base.Flag.Cfg.SpectreIndex {
  5209  		op := ssa.OpSpectreIndex
  5210  		if kind != ssa.BoundsIndex && kind != ssa.BoundsIndexU {
  5211  			op = ssa.OpSpectreSliceIndex
  5212  		}
  5213  		idx = s.newValue2(op, types.Types[types.TINT], idx, len)
  5214  	}
  5215  
  5216  	return idx
  5217  }
  5218  
  5219  // If cmp (a bool) is false, panic using the given function.
  5220  func (s *state) check(cmp *ssa.Value, fn *obj.LSym) {
  5221  	b := s.endBlock()
  5222  	b.Kind = ssa.BlockIf
  5223  	b.SetControl(cmp)
  5224  	b.Likely = ssa.BranchLikely
  5225  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5226  	line := s.peekPos()
  5227  	pos := base.Ctxt.PosTable.Pos(line)
  5228  	fl := funcLine{f: fn, base: pos.Base(), line: pos.Line()}
  5229  	bPanic := s.panics[fl]
  5230  	if bPanic == nil {
  5231  		bPanic = s.f.NewBlock(ssa.BlockPlain)
  5232  		s.panics[fl] = bPanic
  5233  		s.startBlock(bPanic)
  5234  		// The panic call takes/returns memory to ensure that the right
  5235  		// memory state is observed if the panic happens.
  5236  		s.rtcall(fn, false, nil)
  5237  	}
  5238  	b.AddEdgeTo(bNext)
  5239  	b.AddEdgeTo(bPanic)
  5240  	s.startBlock(bNext)
  5241  }
  5242  
  5243  func (s *state) intDivide(n ir.Node, a, b *ssa.Value) *ssa.Value {
  5244  	needcheck := true
  5245  	switch b.Op {
  5246  	case ssa.OpConst8, ssa.OpConst16, ssa.OpConst32, ssa.OpConst64:
  5247  		if b.AuxInt != 0 {
  5248  			needcheck = false
  5249  		}
  5250  	}
  5251  	if needcheck {
  5252  		// do a size-appropriate check for zero
  5253  		cmp := s.newValue2(s.ssaOp(ir.ONE, n.Type()), types.Types[types.TBOOL], b, s.zeroVal(n.Type()))
  5254  		s.check(cmp, ir.Syms.Panicdivide)
  5255  	}
  5256  	return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  5257  }
  5258  
  5259  // rtcall issues a call to the given runtime function fn with the listed args.
  5260  // Returns a slice of results of the given result types.
  5261  // The call is added to the end of the current block.
  5262  // If returns is false, the block is marked as an exit block.
  5263  func (s *state) rtcall(fn *obj.LSym, returns bool, results []*types.Type, args ...*ssa.Value) []*ssa.Value {
  5264  	s.prevCall = nil
  5265  	// Write args to the stack
  5266  	off := base.Ctxt.Arch.FixedFrameSize
  5267  	var callArgs []*ssa.Value
  5268  	var callArgTypes []*types.Type
  5269  
  5270  	for _, arg := range args {
  5271  		t := arg.Type
  5272  		off = types.RoundUp(off, t.Alignment())
  5273  		size := t.Size()
  5274  		callArgs = append(callArgs, arg)
  5275  		callArgTypes = append(callArgTypes, t)
  5276  		off += size
  5277  	}
  5278  	off = types.RoundUp(off, int64(types.RegSize))
  5279  
  5280  	// Issue call
  5281  	var call *ssa.Value
  5282  	aux := ssa.StaticAuxCall(fn, s.f.ABIDefault.ABIAnalyzeTypes(callArgTypes, results))
  5283  	callArgs = append(callArgs, s.mem())
  5284  	call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5285  	call.AddArgs(callArgs...)
  5286  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(results)), call)
  5287  
  5288  	if !returns {
  5289  		// Finish block
  5290  		b := s.endBlock()
  5291  		b.Kind = ssa.BlockExit
  5292  		b.SetControl(call)
  5293  		call.AuxInt = off - base.Ctxt.Arch.FixedFrameSize
  5294  		if len(results) > 0 {
  5295  			s.Fatalf("panic call can't have results")
  5296  		}
  5297  		return nil
  5298  	}
  5299  
  5300  	// Load results
  5301  	res := make([]*ssa.Value, len(results))
  5302  	for i, t := range results {
  5303  		off = types.RoundUp(off, t.Alignment())
  5304  		res[i] = s.resultOfCall(call, int64(i), t)
  5305  		off += t.Size()
  5306  	}
  5307  	off = types.RoundUp(off, int64(types.PtrSize))
  5308  
  5309  	// Remember how much callee stack space we needed.
  5310  	call.AuxInt = off
  5311  
  5312  	return res
  5313  }
  5314  
  5315  // do *left = right for type t.
  5316  func (s *state) storeType(t *types.Type, left, right *ssa.Value, skip skipMask, leftIsStmt bool) {
  5317  	s.instrument(t, left, instrumentWrite)
  5318  
  5319  	if skip == 0 && (!t.HasPointers() || ssa.IsStackAddr(left)) {
  5320  		// Known to not have write barrier. Store the whole type.
  5321  		s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, left, right, s.mem(), leftIsStmt)
  5322  		return
  5323  	}
  5324  
  5325  	// store scalar fields first, so write barrier stores for
  5326  	// pointer fields can be grouped together, and scalar values
  5327  	// don't need to be live across the write barrier call.
  5328  	// TODO: if the writebarrier pass knows how to reorder stores,
  5329  	// we can do a single store here as long as skip==0.
  5330  	s.storeTypeScalars(t, left, right, skip)
  5331  	if skip&skipPtr == 0 && t.HasPointers() {
  5332  		s.storeTypePtrs(t, left, right)
  5333  	}
  5334  }
  5335  
  5336  // do *left = right for all scalar (non-pointer) parts of t.
  5337  func (s *state) storeTypeScalars(t *types.Type, left, right *ssa.Value, skip skipMask) {
  5338  	switch {
  5339  	case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex():
  5340  		s.store(t, left, right)
  5341  	case t.IsPtrShaped():
  5342  		if t.IsPtr() && t.Elem().NotInHeap() {
  5343  			s.store(t, left, right) // see issue 42032
  5344  		}
  5345  		// otherwise, no scalar fields.
  5346  	case t.IsString():
  5347  		if skip&skipLen != 0 {
  5348  			return
  5349  		}
  5350  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], right)
  5351  		lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5352  		s.store(types.Types[types.TINT], lenAddr, len)
  5353  	case t.IsSlice():
  5354  		if skip&skipLen == 0 {
  5355  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], right)
  5356  			lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5357  			s.store(types.Types[types.TINT], lenAddr, len)
  5358  		}
  5359  		if skip&skipCap == 0 {
  5360  			cap := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], right)
  5361  			capAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, 2*s.config.PtrSize, left)
  5362  			s.store(types.Types[types.TINT], capAddr, cap)
  5363  		}
  5364  	case t.IsInterface():
  5365  		// itab field doesn't need a write barrier (even though it is a pointer).
  5366  		itab := s.newValue1(ssa.OpITab, s.f.Config.Types.BytePtr, right)
  5367  		s.store(types.Types[types.TUINTPTR], left, itab)
  5368  	case t.IsStruct():
  5369  		n := t.NumFields()
  5370  		for i := 0; i < n; i++ {
  5371  			ft := t.FieldType(i)
  5372  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5373  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5374  			s.storeTypeScalars(ft, addr, val, 0)
  5375  		}
  5376  	case t.IsArray() && t.NumElem() == 0:
  5377  		// nothing
  5378  	case t.IsArray() && t.NumElem() == 1:
  5379  		s.storeTypeScalars(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right), 0)
  5380  	default:
  5381  		s.Fatalf("bad write barrier type %v", t)
  5382  	}
  5383  }
  5384  
  5385  // do *left = right for all pointer parts of t.
  5386  func (s *state) storeTypePtrs(t *types.Type, left, right *ssa.Value) {
  5387  	switch {
  5388  	case t.IsPtrShaped():
  5389  		if t.IsPtr() && t.Elem().NotInHeap() {
  5390  			break // see issue 42032
  5391  		}
  5392  		s.store(t, left, right)
  5393  	case t.IsString():
  5394  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, right)
  5395  		s.store(s.f.Config.Types.BytePtr, left, ptr)
  5396  	case t.IsSlice():
  5397  		elType := types.NewPtr(t.Elem())
  5398  		ptr := s.newValue1(ssa.OpSlicePtr, elType, right)
  5399  		s.store(elType, left, ptr)
  5400  	case t.IsInterface():
  5401  		// itab field is treated as a scalar.
  5402  		idata := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, right)
  5403  		idataAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.BytePtrPtr, s.config.PtrSize, left)
  5404  		s.store(s.f.Config.Types.BytePtr, idataAddr, idata)
  5405  	case t.IsStruct():
  5406  		n := t.NumFields()
  5407  		for i := 0; i < n; i++ {
  5408  			ft := t.FieldType(i)
  5409  			if !ft.HasPointers() {
  5410  				continue
  5411  			}
  5412  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5413  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5414  			s.storeTypePtrs(ft, addr, val)
  5415  		}
  5416  	case t.IsArray() && t.NumElem() == 0:
  5417  		// nothing
  5418  	case t.IsArray() && t.NumElem() == 1:
  5419  		s.storeTypePtrs(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right))
  5420  	default:
  5421  		s.Fatalf("bad write barrier type %v", t)
  5422  	}
  5423  }
  5424  
  5425  // putArg evaluates n for the purpose of passing it as an argument to a function and returns the value for the call.
  5426  func (s *state) putArg(n ir.Node, t *types.Type) *ssa.Value {
  5427  	var a *ssa.Value
  5428  	if !ssa.CanSSA(t) {
  5429  		a = s.newValue2(ssa.OpDereference, t, s.addr(n), s.mem())
  5430  	} else {
  5431  		a = s.expr(n)
  5432  	}
  5433  	return a
  5434  }
  5435  
  5436  func (s *state) storeArgWithBase(n ir.Node, t *types.Type, base *ssa.Value, off int64) {
  5437  	pt := types.NewPtr(t)
  5438  	var addr *ssa.Value
  5439  	if base == s.sp {
  5440  		// Use special routine that avoids allocation on duplicate offsets.
  5441  		addr = s.constOffPtrSP(pt, off)
  5442  	} else {
  5443  		addr = s.newValue1I(ssa.OpOffPtr, pt, off, base)
  5444  	}
  5445  
  5446  	if !ssa.CanSSA(t) {
  5447  		a := s.addr(n)
  5448  		s.move(t, addr, a)
  5449  		return
  5450  	}
  5451  
  5452  	a := s.expr(n)
  5453  	s.storeType(t, addr, a, 0, false)
  5454  }
  5455  
  5456  // slice computes the slice v[i:j:k] and returns ptr, len, and cap of result.
  5457  // i,j,k may be nil, in which case they are set to their default value.
  5458  // v may be a slice, string or pointer to an array.
  5459  func (s *state) slice(v, i, j, k *ssa.Value, bounded bool) (p, l, c *ssa.Value) {
  5460  	t := v.Type
  5461  	var ptr, len, cap *ssa.Value
  5462  	switch {
  5463  	case t.IsSlice():
  5464  		ptr = s.newValue1(ssa.OpSlicePtr, types.NewPtr(t.Elem()), v)
  5465  		len = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  5466  		cap = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], v)
  5467  	case t.IsString():
  5468  		ptr = s.newValue1(ssa.OpStringPtr, types.NewPtr(types.Types[types.TUINT8]), v)
  5469  		len = s.newValue1(ssa.OpStringLen, types.Types[types.TINT], v)
  5470  		cap = len
  5471  	case t.IsPtr():
  5472  		if !t.Elem().IsArray() {
  5473  			s.Fatalf("bad ptr to array in slice %v\n", t)
  5474  		}
  5475  		nv := s.nilCheck(v)
  5476  		ptr = s.newValue1(ssa.OpCopy, types.NewPtr(t.Elem().Elem()), nv)
  5477  		len = s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  5478  		cap = len
  5479  	default:
  5480  		s.Fatalf("bad type in slice %v\n", t)
  5481  	}
  5482  
  5483  	// Set default values
  5484  	if i == nil {
  5485  		i = s.constInt(types.Types[types.TINT], 0)
  5486  	}
  5487  	if j == nil {
  5488  		j = len
  5489  	}
  5490  	three := true
  5491  	if k == nil {
  5492  		three = false
  5493  		k = cap
  5494  	}
  5495  
  5496  	// Panic if slice indices are not in bounds.
  5497  	// Make sure we check these in reverse order so that we're always
  5498  	// comparing against a value known to be nonnegative. See issue 28797.
  5499  	if three {
  5500  		if k != cap {
  5501  			kind := ssa.BoundsSlice3Alen
  5502  			if t.IsSlice() {
  5503  				kind = ssa.BoundsSlice3Acap
  5504  			}
  5505  			k = s.boundsCheck(k, cap, kind, bounded)
  5506  		}
  5507  		if j != k {
  5508  			j = s.boundsCheck(j, k, ssa.BoundsSlice3B, bounded)
  5509  		}
  5510  		i = s.boundsCheck(i, j, ssa.BoundsSlice3C, bounded)
  5511  	} else {
  5512  		if j != k {
  5513  			kind := ssa.BoundsSliceAlen
  5514  			if t.IsSlice() {
  5515  				kind = ssa.BoundsSliceAcap
  5516  			}
  5517  			j = s.boundsCheck(j, k, kind, bounded)
  5518  		}
  5519  		i = s.boundsCheck(i, j, ssa.BoundsSliceB, bounded)
  5520  	}
  5521  
  5522  	// Word-sized integer operations.
  5523  	subOp := s.ssaOp(ir.OSUB, types.Types[types.TINT])
  5524  	mulOp := s.ssaOp(ir.OMUL, types.Types[types.TINT])
  5525  	andOp := s.ssaOp(ir.OAND, types.Types[types.TINT])
  5526  
  5527  	// Calculate the length (rlen) and capacity (rcap) of the new slice.
  5528  	// For strings the capacity of the result is unimportant. However,
  5529  	// we use rcap to test if we've generated a zero-length slice.
  5530  	// Use length of strings for that.
  5531  	rlen := s.newValue2(subOp, types.Types[types.TINT], j, i)
  5532  	rcap := rlen
  5533  	if j != k && !t.IsString() {
  5534  		rcap = s.newValue2(subOp, types.Types[types.TINT], k, i)
  5535  	}
  5536  
  5537  	if (i.Op == ssa.OpConst64 || i.Op == ssa.OpConst32) && i.AuxInt == 0 {
  5538  		// No pointer arithmetic necessary.
  5539  		return ptr, rlen, rcap
  5540  	}
  5541  
  5542  	// Calculate the base pointer (rptr) for the new slice.
  5543  	//
  5544  	// Generate the following code assuming that indexes are in bounds.
  5545  	// The masking is to make sure that we don't generate a slice
  5546  	// that points to the next object in memory. We cannot just set
  5547  	// the pointer to nil because then we would create a nil slice or
  5548  	// string.
  5549  	//
  5550  	//     rcap = k - i
  5551  	//     rlen = j - i
  5552  	//     rptr = ptr + (mask(rcap) & (i * stride))
  5553  	//
  5554  	// Where mask(x) is 0 if x==0 and -1 if x>0 and stride is the width
  5555  	// of the element type.
  5556  	stride := s.constInt(types.Types[types.TINT], ptr.Type.Elem().Size())
  5557  
  5558  	// The delta is the number of bytes to offset ptr by.
  5559  	delta := s.newValue2(mulOp, types.Types[types.TINT], i, stride)
  5560  
  5561  	// If we're slicing to the point where the capacity is zero,
  5562  	// zero out the delta.
  5563  	mask := s.newValue1(ssa.OpSlicemask, types.Types[types.TINT], rcap)
  5564  	delta = s.newValue2(andOp, types.Types[types.TINT], delta, mask)
  5565  
  5566  	// Compute rptr = ptr + delta.
  5567  	rptr := s.newValue2(ssa.OpAddPtr, ptr.Type, ptr, delta)
  5568  
  5569  	return rptr, rlen, rcap
  5570  }
  5571  
  5572  type u642fcvtTab struct {
  5573  	leq, cvt2F, and, rsh, or, add ssa.Op
  5574  	one                           func(*state, *types.Type, int64) *ssa.Value
  5575  }
  5576  
  5577  var u64_f64 = u642fcvtTab{
  5578  	leq:   ssa.OpLeq64,
  5579  	cvt2F: ssa.OpCvt64to64F,
  5580  	and:   ssa.OpAnd64,
  5581  	rsh:   ssa.OpRsh64Ux64,
  5582  	or:    ssa.OpOr64,
  5583  	add:   ssa.OpAdd64F,
  5584  	one:   (*state).constInt64,
  5585  }
  5586  
  5587  var u64_f32 = u642fcvtTab{
  5588  	leq:   ssa.OpLeq64,
  5589  	cvt2F: ssa.OpCvt64to32F,
  5590  	and:   ssa.OpAnd64,
  5591  	rsh:   ssa.OpRsh64Ux64,
  5592  	or:    ssa.OpOr64,
  5593  	add:   ssa.OpAdd32F,
  5594  	one:   (*state).constInt64,
  5595  }
  5596  
  5597  func (s *state) uint64Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5598  	return s.uint64Tofloat(&u64_f64, n, x, ft, tt)
  5599  }
  5600  
  5601  func (s *state) uint64Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5602  	return s.uint64Tofloat(&u64_f32, n, x, ft, tt)
  5603  }
  5604  
  5605  func (s *state) uint64Tofloat(cvttab *u642fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5606  	// if x >= 0 {
  5607  	//    result = (floatY) x
  5608  	// } else {
  5609  	// 	  y = uintX(x) ; y = x & 1
  5610  	// 	  z = uintX(x) ; z = z >> 1
  5611  	// 	  z = z | y
  5612  	// 	  result = floatY(z)
  5613  	// 	  result = result + result
  5614  	// }
  5615  	//
  5616  	// Code borrowed from old code generator.
  5617  	// What's going on: large 64-bit "unsigned" looks like
  5618  	// negative number to hardware's integer-to-float
  5619  	// conversion. However, because the mantissa is only
  5620  	// 63 bits, we don't need the LSB, so instead we do an
  5621  	// unsigned right shift (divide by two), convert, and
  5622  	// double. However, before we do that, we need to be
  5623  	// sure that we do not lose a "1" if that made the
  5624  	// difference in the resulting rounding. Therefore, we
  5625  	// preserve it, and OR (not ADD) it back in. The case
  5626  	// that matters is when the eleven discarded bits are
  5627  	// equal to 10000000001; that rounds up, and the 1 cannot
  5628  	// be lost else it would round down if the LSB of the
  5629  	// candidate mantissa is 0.
  5630  	cmp := s.newValue2(cvttab.leq, types.Types[types.TBOOL], s.zeroVal(ft), x)
  5631  	b := s.endBlock()
  5632  	b.Kind = ssa.BlockIf
  5633  	b.SetControl(cmp)
  5634  	b.Likely = ssa.BranchLikely
  5635  
  5636  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5637  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5638  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5639  
  5640  	b.AddEdgeTo(bThen)
  5641  	s.startBlock(bThen)
  5642  	a0 := s.newValue1(cvttab.cvt2F, tt, x)
  5643  	s.vars[n] = a0
  5644  	s.endBlock()
  5645  	bThen.AddEdgeTo(bAfter)
  5646  
  5647  	b.AddEdgeTo(bElse)
  5648  	s.startBlock(bElse)
  5649  	one := cvttab.one(s, ft, 1)
  5650  	y := s.newValue2(cvttab.and, ft, x, one)
  5651  	z := s.newValue2(cvttab.rsh, ft, x, one)
  5652  	z = s.newValue2(cvttab.or, ft, z, y)
  5653  	a := s.newValue1(cvttab.cvt2F, tt, z)
  5654  	a1 := s.newValue2(cvttab.add, tt, a, a)
  5655  	s.vars[n] = a1
  5656  	s.endBlock()
  5657  	bElse.AddEdgeTo(bAfter)
  5658  
  5659  	s.startBlock(bAfter)
  5660  	return s.variable(n, n.Type())
  5661  }
  5662  
  5663  type u322fcvtTab struct {
  5664  	cvtI2F, cvtF2F ssa.Op
  5665  }
  5666  
  5667  var u32_f64 = u322fcvtTab{
  5668  	cvtI2F: ssa.OpCvt32to64F,
  5669  	cvtF2F: ssa.OpCopy,
  5670  }
  5671  
  5672  var u32_f32 = u322fcvtTab{
  5673  	cvtI2F: ssa.OpCvt32to32F,
  5674  	cvtF2F: ssa.OpCvt64Fto32F,
  5675  }
  5676  
  5677  func (s *state) uint32Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5678  	return s.uint32Tofloat(&u32_f64, n, x, ft, tt)
  5679  }
  5680  
  5681  func (s *state) uint32Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5682  	return s.uint32Tofloat(&u32_f32, n, x, ft, tt)
  5683  }
  5684  
  5685  func (s *state) uint32Tofloat(cvttab *u322fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5686  	// if x >= 0 {
  5687  	// 	result = floatY(x)
  5688  	// } else {
  5689  	// 	result = floatY(float64(x) + (1<<32))
  5690  	// }
  5691  	cmp := s.newValue2(ssa.OpLeq32, types.Types[types.TBOOL], s.zeroVal(ft), x)
  5692  	b := s.endBlock()
  5693  	b.Kind = ssa.BlockIf
  5694  	b.SetControl(cmp)
  5695  	b.Likely = ssa.BranchLikely
  5696  
  5697  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5698  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5699  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5700  
  5701  	b.AddEdgeTo(bThen)
  5702  	s.startBlock(bThen)
  5703  	a0 := s.newValue1(cvttab.cvtI2F, tt, x)
  5704  	s.vars[n] = a0
  5705  	s.endBlock()
  5706  	bThen.AddEdgeTo(bAfter)
  5707  
  5708  	b.AddEdgeTo(bElse)
  5709  	s.startBlock(bElse)
  5710  	a1 := s.newValue1(ssa.OpCvt32to64F, types.Types[types.TFLOAT64], x)
  5711  	twoToThe32 := s.constFloat64(types.Types[types.TFLOAT64], float64(1<<32))
  5712  	a2 := s.newValue2(ssa.OpAdd64F, types.Types[types.TFLOAT64], a1, twoToThe32)
  5713  	a3 := s.newValue1(cvttab.cvtF2F, tt, a2)
  5714  
  5715  	s.vars[n] = a3
  5716  	s.endBlock()
  5717  	bElse.AddEdgeTo(bAfter)
  5718  
  5719  	s.startBlock(bAfter)
  5720  	return s.variable(n, n.Type())
  5721  }
  5722  
  5723  // referenceTypeBuiltin generates code for the len/cap builtins for maps and channels.
  5724  func (s *state) referenceTypeBuiltin(n *ir.UnaryExpr, x *ssa.Value) *ssa.Value {
  5725  	if !n.X.Type().IsMap() && !n.X.Type().IsChan() {
  5726  		s.Fatalf("node must be a map or a channel")
  5727  	}
  5728  	if n.X.Type().IsChan() && n.Op() == ir.OLEN {
  5729  		s.Fatalf("cannot inline len(chan)") // must use runtime.chanlen now
  5730  	}
  5731  	if n.X.Type().IsChan() && n.Op() == ir.OCAP {
  5732  		s.Fatalf("cannot inline cap(chan)") // must use runtime.chancap now
  5733  	}
  5734  	if n.X.Type().IsMap() && n.Op() == ir.OCAP {
  5735  		s.Fatalf("cannot inline cap(map)") // cap(map) does not exist
  5736  	}
  5737  	// if n == nil {
  5738  	//   return 0
  5739  	// } else {
  5740  	//   // len, the actual loadType depends
  5741  	//   return int(*((*loadType)n))
  5742  	//   // cap (chan only, not used for now)
  5743  	//   return *(((*int)n)+1)
  5744  	// }
  5745  	lenType := n.Type()
  5746  	nilValue := s.constNil(types.Types[types.TUINTPTR])
  5747  	cmp := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], x, nilValue)
  5748  	b := s.endBlock()
  5749  	b.Kind = ssa.BlockIf
  5750  	b.SetControl(cmp)
  5751  	b.Likely = ssa.BranchUnlikely
  5752  
  5753  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5754  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5755  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5756  
  5757  	// length/capacity of a nil map/chan is zero
  5758  	b.AddEdgeTo(bThen)
  5759  	s.startBlock(bThen)
  5760  	s.vars[n] = s.zeroVal(lenType)
  5761  	s.endBlock()
  5762  	bThen.AddEdgeTo(bAfter)
  5763  
  5764  	b.AddEdgeTo(bElse)
  5765  	s.startBlock(bElse)
  5766  	switch n.Op() {
  5767  	case ir.OLEN:
  5768  		if buildcfg.Experiment.SwissMap && n.X.Type().IsMap() {
  5769  			// length is stored in the first word.
  5770  			loadType := reflectdata.SwissMapType().Field(0).Type // uint64
  5771  			load := s.load(loadType, x)
  5772  			s.vars[n] = s.conv(nil, load, loadType, lenType) // integer conversion doesn't need Node
  5773  		} else {
  5774  			// length is stored in the first word for map/chan
  5775  			s.vars[n] = s.load(lenType, x)
  5776  		}
  5777  	case ir.OCAP:
  5778  		// capacity is stored in the second word for chan
  5779  		sw := s.newValue1I(ssa.OpOffPtr, lenType.PtrTo(), lenType.Size(), x)
  5780  		s.vars[n] = s.load(lenType, sw)
  5781  	default:
  5782  		s.Fatalf("op must be OLEN or OCAP")
  5783  	}
  5784  	s.endBlock()
  5785  	bElse.AddEdgeTo(bAfter)
  5786  
  5787  	s.startBlock(bAfter)
  5788  	return s.variable(n, lenType)
  5789  }
  5790  
  5791  type f2uCvtTab struct {
  5792  	ltf, cvt2U, subf, or ssa.Op
  5793  	floatValue           func(*state, *types.Type, float64) *ssa.Value
  5794  	intValue             func(*state, *types.Type, int64) *ssa.Value
  5795  	cutoff               uint64
  5796  }
  5797  
  5798  var f32_u64 = f2uCvtTab{
  5799  	ltf:        ssa.OpLess32F,
  5800  	cvt2U:      ssa.OpCvt32Fto64,
  5801  	subf:       ssa.OpSub32F,
  5802  	or:         ssa.OpOr64,
  5803  	floatValue: (*state).constFloat32,
  5804  	intValue:   (*state).constInt64,
  5805  	cutoff:     1 << 63,
  5806  }
  5807  
  5808  var f64_u64 = f2uCvtTab{
  5809  	ltf:        ssa.OpLess64F,
  5810  	cvt2U:      ssa.OpCvt64Fto64,
  5811  	subf:       ssa.OpSub64F,
  5812  	or:         ssa.OpOr64,
  5813  	floatValue: (*state).constFloat64,
  5814  	intValue:   (*state).constInt64,
  5815  	cutoff:     1 << 63,
  5816  }
  5817  
  5818  var f32_u32 = f2uCvtTab{
  5819  	ltf:        ssa.OpLess32F,
  5820  	cvt2U:      ssa.OpCvt32Fto32,
  5821  	subf:       ssa.OpSub32F,
  5822  	or:         ssa.OpOr32,
  5823  	floatValue: (*state).constFloat32,
  5824  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  5825  	cutoff:     1 << 31,
  5826  }
  5827  
  5828  var f64_u32 = f2uCvtTab{
  5829  	ltf:        ssa.OpLess64F,
  5830  	cvt2U:      ssa.OpCvt64Fto32,
  5831  	subf:       ssa.OpSub64F,
  5832  	or:         ssa.OpOr32,
  5833  	floatValue: (*state).constFloat64,
  5834  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  5835  	cutoff:     1 << 31,
  5836  }
  5837  
  5838  func (s *state) float32ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5839  	return s.floatToUint(&f32_u64, n, x, ft, tt)
  5840  }
  5841  func (s *state) float64ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5842  	return s.floatToUint(&f64_u64, n, x, ft, tt)
  5843  }
  5844  
  5845  func (s *state) float32ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5846  	return s.floatToUint(&f32_u32, n, x, ft, tt)
  5847  }
  5848  
  5849  func (s *state) float64ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5850  	return s.floatToUint(&f64_u32, n, x, ft, tt)
  5851  }
  5852  
  5853  func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5854  	// cutoff:=1<<(intY_Size-1)
  5855  	// if x < floatX(cutoff) {
  5856  	// 	result = uintY(x)
  5857  	// } else {
  5858  	// 	y = x - floatX(cutoff)
  5859  	// 	z = uintY(y)
  5860  	// 	result = z | -(cutoff)
  5861  	// }
  5862  	cutoff := cvttab.floatValue(s, ft, float64(cvttab.cutoff))
  5863  	cmp := s.newValue2(cvttab.ltf, types.Types[types.TBOOL], x, cutoff)
  5864  	b := s.endBlock()
  5865  	b.Kind = ssa.BlockIf
  5866  	b.SetControl(cmp)
  5867  	b.Likely = ssa.BranchLikely
  5868  
  5869  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5870  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5871  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5872  
  5873  	b.AddEdgeTo(bThen)
  5874  	s.startBlock(bThen)
  5875  	a0 := s.newValue1(cvttab.cvt2U, tt, x)
  5876  	s.vars[n] = a0
  5877  	s.endBlock()
  5878  	bThen.AddEdgeTo(bAfter)
  5879  
  5880  	b.AddEdgeTo(bElse)
  5881  	s.startBlock(bElse)
  5882  	y := s.newValue2(cvttab.subf, ft, x, cutoff)
  5883  	y = s.newValue1(cvttab.cvt2U, tt, y)
  5884  	z := cvttab.intValue(s, tt, int64(-cvttab.cutoff))
  5885  	a1 := s.newValue2(cvttab.or, tt, y, z)
  5886  	s.vars[n] = a1
  5887  	s.endBlock()
  5888  	bElse.AddEdgeTo(bAfter)
  5889  
  5890  	s.startBlock(bAfter)
  5891  	return s.variable(n, n.Type())
  5892  }
  5893  
  5894  // dottype generates SSA for a type assertion node.
  5895  // commaok indicates whether to panic or return a bool.
  5896  // If commaok is false, resok will be nil.
  5897  func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  5898  	iface := s.expr(n.X)              // input interface
  5899  	target := s.reflectType(n.Type()) // target type
  5900  	var targetItab *ssa.Value
  5901  	if n.ITab != nil {
  5902  		targetItab = s.expr(n.ITab)
  5903  	}
  5904  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, nil, target, targetItab, commaok, n.Descriptor)
  5905  }
  5906  
  5907  func (s *state) dynamicDottype(n *ir.DynamicTypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  5908  	iface := s.expr(n.X)
  5909  	var source, target, targetItab *ssa.Value
  5910  	if n.SrcRType != nil {
  5911  		source = s.expr(n.SrcRType)
  5912  	}
  5913  	if !n.X.Type().IsEmptyInterface() && !n.Type().IsInterface() {
  5914  		byteptr := s.f.Config.Types.BytePtr
  5915  		targetItab = s.expr(n.ITab)
  5916  		// TODO(mdempsky): Investigate whether compiling n.RType could be
  5917  		// better than loading itab.typ.
  5918  		target = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), targetItab))
  5919  	} else {
  5920  		target = s.expr(n.RType)
  5921  	}
  5922  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, source, target, targetItab, commaok, nil)
  5923  }
  5924  
  5925  // dottype1 implements a x.(T) operation. iface is the argument (x), dst is the type we're asserting to (T)
  5926  // and src is the type we're asserting from.
  5927  // source is the *runtime._type of src
  5928  // target is the *runtime._type of dst.
  5929  // If src is a nonempty interface and dst is not an interface, targetItab is an itab representing (dst, src). Otherwise it is nil.
  5930  // commaok is true if the caller wants a boolean success value. Otherwise, the generated code panics if the conversion fails.
  5931  // descriptor is a compiler-allocated internal/abi.TypeAssert whose address is passed to runtime.typeAssert when
  5932  // the target type is a compile-time-known non-empty interface. It may be nil.
  5933  func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, source, target, targetItab *ssa.Value, commaok bool, descriptor *obj.LSym) (res, resok *ssa.Value) {
  5934  	typs := s.f.Config.Types
  5935  	byteptr := typs.BytePtr
  5936  	if dst.IsInterface() {
  5937  		if dst.IsEmptyInterface() {
  5938  			// Converting to an empty interface.
  5939  			// Input could be an empty or nonempty interface.
  5940  			if base.Debug.TypeAssert > 0 {
  5941  				base.WarnfAt(pos, "type assertion inlined")
  5942  			}
  5943  
  5944  			// Get itab/type field from input.
  5945  			itab := s.newValue1(ssa.OpITab, byteptr, iface)
  5946  			// Conversion succeeds iff that field is not nil.
  5947  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  5948  
  5949  			if src.IsEmptyInterface() && commaok {
  5950  				// Converting empty interface to empty interface with ,ok is just a nil check.
  5951  				return iface, cond
  5952  			}
  5953  
  5954  			// Branch on nilness.
  5955  			b := s.endBlock()
  5956  			b.Kind = ssa.BlockIf
  5957  			b.SetControl(cond)
  5958  			b.Likely = ssa.BranchLikely
  5959  			bOk := s.f.NewBlock(ssa.BlockPlain)
  5960  			bFail := s.f.NewBlock(ssa.BlockPlain)
  5961  			b.AddEdgeTo(bOk)
  5962  			b.AddEdgeTo(bFail)
  5963  
  5964  			if !commaok {
  5965  				// On failure, panic by calling panicnildottype.
  5966  				s.startBlock(bFail)
  5967  				s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  5968  
  5969  				// On success, return (perhaps modified) input interface.
  5970  				s.startBlock(bOk)
  5971  				if src.IsEmptyInterface() {
  5972  					res = iface // Use input interface unchanged.
  5973  					return
  5974  				}
  5975  				// Load type out of itab, build interface with existing idata.
  5976  				off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
  5977  				typ := s.load(byteptr, off)
  5978  				idata := s.newValue1(ssa.OpIData, byteptr, iface)
  5979  				res = s.newValue2(ssa.OpIMake, dst, typ, idata)
  5980  				return
  5981  			}
  5982  
  5983  			s.startBlock(bOk)
  5984  			// nonempty -> empty
  5985  			// Need to load type from itab
  5986  			off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
  5987  			s.vars[typVar] = s.load(byteptr, off)
  5988  			s.endBlock()
  5989  
  5990  			// itab is nil, might as well use that as the nil result.
  5991  			s.startBlock(bFail)
  5992  			s.vars[typVar] = itab
  5993  			s.endBlock()
  5994  
  5995  			// Merge point.
  5996  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  5997  			bOk.AddEdgeTo(bEnd)
  5998  			bFail.AddEdgeTo(bEnd)
  5999  			s.startBlock(bEnd)
  6000  			idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6001  			res = s.newValue2(ssa.OpIMake, dst, s.variable(typVar, byteptr), idata)
  6002  			resok = cond
  6003  			delete(s.vars, typVar) // no practical effect, just to indicate typVar is no longer live.
  6004  			return
  6005  		}
  6006  		// converting to a nonempty interface needs a runtime call.
  6007  		if base.Debug.TypeAssert > 0 {
  6008  			base.WarnfAt(pos, "type assertion not inlined")
  6009  		}
  6010  
  6011  		itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6012  		data := s.newValue1(ssa.OpIData, types.Types[types.TUNSAFEPTR], iface)
  6013  
  6014  		// First, check for nil.
  6015  		bNil := s.f.NewBlock(ssa.BlockPlain)
  6016  		bNonNil := s.f.NewBlock(ssa.BlockPlain)
  6017  		bMerge := s.f.NewBlock(ssa.BlockPlain)
  6018  		cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6019  		b := s.endBlock()
  6020  		b.Kind = ssa.BlockIf
  6021  		b.SetControl(cond)
  6022  		b.Likely = ssa.BranchLikely
  6023  		b.AddEdgeTo(bNonNil)
  6024  		b.AddEdgeTo(bNil)
  6025  
  6026  		s.startBlock(bNil)
  6027  		if commaok {
  6028  			s.vars[typVar] = itab // which will be nil
  6029  			b := s.endBlock()
  6030  			b.AddEdgeTo(bMerge)
  6031  		} else {
  6032  			// Panic if input is nil.
  6033  			s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6034  		}
  6035  
  6036  		// Get typ, possibly by loading out of itab.
  6037  		s.startBlock(bNonNil)
  6038  		typ := itab
  6039  		if !src.IsEmptyInterface() {
  6040  			typ = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab))
  6041  		}
  6042  
  6043  		// Check the cache first.
  6044  		var d *ssa.Value
  6045  		if descriptor != nil {
  6046  			d = s.newValue1A(ssa.OpAddr, byteptr, descriptor, s.sb)
  6047  			if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Family) {
  6048  				// Note: we can only use the cache if we have the right atomic load instruction.
  6049  				// Double-check that here.
  6050  				if intrinsics.lookup(Arch.LinkArch.Arch, "internal/runtime/atomic", "Loadp") == nil {
  6051  					s.Fatalf("atomic load not available")
  6052  				}
  6053  				// Pick right size ops.
  6054  				var mul, and, add, zext ssa.Op
  6055  				if s.config.PtrSize == 4 {
  6056  					mul = ssa.OpMul32
  6057  					and = ssa.OpAnd32
  6058  					add = ssa.OpAdd32
  6059  					zext = ssa.OpCopy
  6060  				} else {
  6061  					mul = ssa.OpMul64
  6062  					and = ssa.OpAnd64
  6063  					add = ssa.OpAdd64
  6064  					zext = ssa.OpZeroExt32to64
  6065  				}
  6066  
  6067  				loopHead := s.f.NewBlock(ssa.BlockPlain)
  6068  				loopBody := s.f.NewBlock(ssa.BlockPlain)
  6069  				cacheHit := s.f.NewBlock(ssa.BlockPlain)
  6070  				cacheMiss := s.f.NewBlock(ssa.BlockPlain)
  6071  
  6072  				// Load cache pointer out of descriptor, with an atomic load so
  6073  				// we ensure that we see a fully written cache.
  6074  				atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  6075  				cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  6076  				s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  6077  
  6078  				// Load hash from type or itab.
  6079  				var hash *ssa.Value
  6080  				if src.IsEmptyInterface() {
  6081  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, rttype.Type.OffsetOf("Hash"), typ), s.mem())
  6082  				} else {
  6083  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, rttype.ITab.OffsetOf("Hash"), itab), s.mem())
  6084  				}
  6085  				hash = s.newValue1(zext, typs.Uintptr, hash)
  6086  				s.vars[hashVar] = hash
  6087  				// Load mask from cache.
  6088  				mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  6089  				// Jump to loop head.
  6090  				b := s.endBlock()
  6091  				b.AddEdgeTo(loopHead)
  6092  
  6093  				// At loop head, get pointer to the cache entry.
  6094  				//   e := &cache.Entries[hash&mask]
  6095  				s.startBlock(loopHead)
  6096  				idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  6097  				idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(2*s.config.PtrSize)))
  6098  				idx = s.newValue2(add, typs.Uintptr, idx, s.uintptrConstant(uint64(s.config.PtrSize)))
  6099  				e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, idx)
  6100  				//   hash++
  6101  				s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  6102  
  6103  				// Look for a cache hit.
  6104  				//   if e.Typ == typ { goto hit }
  6105  				eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  6106  				cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, typ, eTyp)
  6107  				b = s.endBlock()
  6108  				b.Kind = ssa.BlockIf
  6109  				b.SetControl(cmp1)
  6110  				b.AddEdgeTo(cacheHit)
  6111  				b.AddEdgeTo(loopBody)
  6112  
  6113  				// Look for an empty entry, the tombstone for this hash table.
  6114  				//   if e.Typ == nil { goto miss }
  6115  				s.startBlock(loopBody)
  6116  				cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  6117  				b = s.endBlock()
  6118  				b.Kind = ssa.BlockIf
  6119  				b.SetControl(cmp2)
  6120  				b.AddEdgeTo(cacheMiss)
  6121  				b.AddEdgeTo(loopHead)
  6122  
  6123  				// On a hit, load the data fields of the cache entry.
  6124  				//   Itab = e.Itab
  6125  				s.startBlock(cacheHit)
  6126  				eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, s.config.PtrSize, e), s.mem())
  6127  				s.vars[typVar] = eItab
  6128  				b = s.endBlock()
  6129  				b.AddEdgeTo(bMerge)
  6130  
  6131  				// On a miss, call into the runtime to get the answer.
  6132  				s.startBlock(cacheMiss)
  6133  			}
  6134  		}
  6135  
  6136  		// Call into runtime to get itab for result.
  6137  		if descriptor != nil {
  6138  			itab = s.rtcall(ir.Syms.TypeAssert, true, []*types.Type{byteptr}, d, typ)[0]
  6139  		} else {
  6140  			var fn *obj.LSym
  6141  			if commaok {
  6142  				fn = ir.Syms.AssertE2I2
  6143  			} else {
  6144  				fn = ir.Syms.AssertE2I
  6145  			}
  6146  			itab = s.rtcall(fn, true, []*types.Type{byteptr}, target, typ)[0]
  6147  		}
  6148  		s.vars[typVar] = itab
  6149  		b = s.endBlock()
  6150  		b.AddEdgeTo(bMerge)
  6151  
  6152  		// Build resulting interface.
  6153  		s.startBlock(bMerge)
  6154  		itab = s.variable(typVar, byteptr)
  6155  		var ok *ssa.Value
  6156  		if commaok {
  6157  			ok = s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6158  		}
  6159  		return s.newValue2(ssa.OpIMake, dst, itab, data), ok
  6160  	}
  6161  
  6162  	if base.Debug.TypeAssert > 0 {
  6163  		base.WarnfAt(pos, "type assertion inlined")
  6164  	}
  6165  
  6166  	// Converting to a concrete type.
  6167  	direct := types.IsDirectIface(dst)
  6168  	itab := s.newValue1(ssa.OpITab, byteptr, iface) // type word of interface
  6169  	if base.Debug.TypeAssert > 0 {
  6170  		base.WarnfAt(pos, "type assertion inlined")
  6171  	}
  6172  	var wantedFirstWord *ssa.Value
  6173  	if src.IsEmptyInterface() {
  6174  		// Looking for pointer to target type.
  6175  		wantedFirstWord = target
  6176  	} else {
  6177  		// Looking for pointer to itab for target type and source interface.
  6178  		wantedFirstWord = targetItab
  6179  	}
  6180  
  6181  	var tmp ir.Node     // temporary for use with large types
  6182  	var addr *ssa.Value // address of tmp
  6183  	if commaok && !ssa.CanSSA(dst) {
  6184  		// unSSAable type, use temporary.
  6185  		// TODO: get rid of some of these temporaries.
  6186  		tmp, addr = s.temp(pos, dst)
  6187  	}
  6188  
  6189  	cond := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], itab, wantedFirstWord)
  6190  	b := s.endBlock()
  6191  	b.Kind = ssa.BlockIf
  6192  	b.SetControl(cond)
  6193  	b.Likely = ssa.BranchLikely
  6194  
  6195  	bOk := s.f.NewBlock(ssa.BlockPlain)
  6196  	bFail := s.f.NewBlock(ssa.BlockPlain)
  6197  	b.AddEdgeTo(bOk)
  6198  	b.AddEdgeTo(bFail)
  6199  
  6200  	if !commaok {
  6201  		// on failure, panic by calling panicdottype
  6202  		s.startBlock(bFail)
  6203  		taddr := source
  6204  		if taddr == nil {
  6205  			taddr = s.reflectType(src)
  6206  		}
  6207  		if src.IsEmptyInterface() {
  6208  			s.rtcall(ir.Syms.PanicdottypeE, false, nil, itab, target, taddr)
  6209  		} else {
  6210  			s.rtcall(ir.Syms.PanicdottypeI, false, nil, itab, target, taddr)
  6211  		}
  6212  
  6213  		// on success, return data from interface
  6214  		s.startBlock(bOk)
  6215  		if direct {
  6216  			return s.newValue1(ssa.OpIData, dst, iface), nil
  6217  		}
  6218  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6219  		return s.load(dst, p), nil
  6220  	}
  6221  
  6222  	// commaok is the more complicated case because we have
  6223  	// a control flow merge point.
  6224  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  6225  	// Note that we need a new valVar each time (unlike okVar where we can
  6226  	// reuse the variable) because it might have a different type every time.
  6227  	valVar := ssaMarker("val")
  6228  
  6229  	// type assertion succeeded
  6230  	s.startBlock(bOk)
  6231  	if tmp == nil {
  6232  		if direct {
  6233  			s.vars[valVar] = s.newValue1(ssa.OpIData, dst, iface)
  6234  		} else {
  6235  			p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6236  			s.vars[valVar] = s.load(dst, p)
  6237  		}
  6238  	} else {
  6239  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6240  		s.move(dst, addr, p)
  6241  	}
  6242  	s.vars[okVar] = s.constBool(true)
  6243  	s.endBlock()
  6244  	bOk.AddEdgeTo(bEnd)
  6245  
  6246  	// type assertion failed
  6247  	s.startBlock(bFail)
  6248  	if tmp == nil {
  6249  		s.vars[valVar] = s.zeroVal(dst)
  6250  	} else {
  6251  		s.zero(dst, addr)
  6252  	}
  6253  	s.vars[okVar] = s.constBool(false)
  6254  	s.endBlock()
  6255  	bFail.AddEdgeTo(bEnd)
  6256  
  6257  	// merge point
  6258  	s.startBlock(bEnd)
  6259  	if tmp == nil {
  6260  		res = s.variable(valVar, dst)
  6261  		delete(s.vars, valVar) // no practical effect, just to indicate typVar is no longer live.
  6262  	} else {
  6263  		res = s.load(dst, addr)
  6264  	}
  6265  	resok = s.variable(okVar, types.Types[types.TBOOL])
  6266  	delete(s.vars, okVar) // ditto
  6267  	return res, resok
  6268  }
  6269  
  6270  // temp allocates a temp of type t at position pos
  6271  func (s *state) temp(pos src.XPos, t *types.Type) (*ir.Name, *ssa.Value) {
  6272  	tmp := typecheck.TempAt(pos, s.curfn, t)
  6273  	if t.HasPointers() || (ssa.IsMergeCandidate(tmp) && t != deferstruct()) {
  6274  		s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp, s.mem())
  6275  	}
  6276  	addr := s.addr(tmp)
  6277  	return tmp, addr
  6278  }
  6279  
  6280  // variable returns the value of a variable at the current location.
  6281  func (s *state) variable(n ir.Node, t *types.Type) *ssa.Value {
  6282  	v := s.vars[n]
  6283  	if v != nil {
  6284  		return v
  6285  	}
  6286  	v = s.fwdVars[n]
  6287  	if v != nil {
  6288  		return v
  6289  	}
  6290  
  6291  	if s.curBlock == s.f.Entry {
  6292  		// No variable should be live at entry.
  6293  		s.f.Fatalf("value %v (%v) incorrectly live at entry", n, v)
  6294  	}
  6295  	// Make a FwdRef, which records a value that's live on block input.
  6296  	// We'll find the matching definition as part of insertPhis.
  6297  	v = s.newValue0A(ssa.OpFwdRef, t, fwdRefAux{N: n})
  6298  	s.fwdVars[n] = v
  6299  	if n.Op() == ir.ONAME {
  6300  		s.addNamedValue(n.(*ir.Name), v)
  6301  	}
  6302  	return v
  6303  }
  6304  
  6305  func (s *state) mem() *ssa.Value {
  6306  	return s.variable(memVar, types.TypeMem)
  6307  }
  6308  
  6309  func (s *state) addNamedValue(n *ir.Name, v *ssa.Value) {
  6310  	if n.Class == ir.Pxxx {
  6311  		// Don't track our marker nodes (memVar etc.).
  6312  		return
  6313  	}
  6314  	if ir.IsAutoTmp(n) {
  6315  		// Don't track temporary variables.
  6316  		return
  6317  	}
  6318  	if n.Class == ir.PPARAMOUT {
  6319  		// Don't track named output values.  This prevents return values
  6320  		// from being assigned too early. See #14591 and #14762. TODO: allow this.
  6321  		return
  6322  	}
  6323  	loc := ssa.LocalSlot{N: n, Type: n.Type(), Off: 0}
  6324  	values, ok := s.f.NamedValues[loc]
  6325  	if !ok {
  6326  		s.f.Names = append(s.f.Names, &loc)
  6327  		s.f.CanonicalLocalSlots[loc] = &loc
  6328  	}
  6329  	s.f.NamedValues[loc] = append(values, v)
  6330  }
  6331  
  6332  // Branch is an unresolved branch.
  6333  type Branch struct {
  6334  	P *obj.Prog  // branch instruction
  6335  	B *ssa.Block // target
  6336  }
  6337  
  6338  // State contains state needed during Prog generation.
  6339  type State struct {
  6340  	ABI obj.ABI
  6341  
  6342  	pp *objw.Progs
  6343  
  6344  	// Branches remembers all the branch instructions we've seen
  6345  	// and where they would like to go.
  6346  	Branches []Branch
  6347  
  6348  	// JumpTables remembers all the jump tables we've seen.
  6349  	JumpTables []*ssa.Block
  6350  
  6351  	// bstart remembers where each block starts (indexed by block ID)
  6352  	bstart []*obj.Prog
  6353  
  6354  	maxarg int64 // largest frame size for arguments to calls made by the function
  6355  
  6356  	// Map from GC safe points to liveness index, generated by
  6357  	// liveness analysis.
  6358  	livenessMap liveness.Map
  6359  
  6360  	// partLiveArgs includes arguments that may be partially live, for which we
  6361  	// need to generate instructions that spill the argument registers.
  6362  	partLiveArgs map[*ir.Name]bool
  6363  
  6364  	// lineRunStart records the beginning of the current run of instructions
  6365  	// within a single block sharing the same line number
  6366  	// Used to move statement marks to the beginning of such runs.
  6367  	lineRunStart *obj.Prog
  6368  
  6369  	// wasm: The number of values on the WebAssembly stack. This is only used as a safeguard.
  6370  	OnWasmStackSkipped int
  6371  }
  6372  
  6373  func (s *State) FuncInfo() *obj.FuncInfo {
  6374  	return s.pp.CurFunc.LSym.Func()
  6375  }
  6376  
  6377  // Prog appends a new Prog.
  6378  func (s *State) Prog(as obj.As) *obj.Prog {
  6379  	p := s.pp.Prog(as)
  6380  	if objw.LosesStmtMark(as) {
  6381  		return p
  6382  	}
  6383  	// Float a statement start to the beginning of any same-line run.
  6384  	// lineRunStart is reset at block boundaries, which appears to work well.
  6385  	if s.lineRunStart == nil || s.lineRunStart.Pos.Line() != p.Pos.Line() {
  6386  		s.lineRunStart = p
  6387  	} else if p.Pos.IsStmt() == src.PosIsStmt {
  6388  		s.lineRunStart.Pos = s.lineRunStart.Pos.WithIsStmt()
  6389  		p.Pos = p.Pos.WithNotStmt()
  6390  	}
  6391  	return p
  6392  }
  6393  
  6394  // Pc returns the current Prog.
  6395  func (s *State) Pc() *obj.Prog {
  6396  	return s.pp.Next
  6397  }
  6398  
  6399  // SetPos sets the current source position.
  6400  func (s *State) SetPos(pos src.XPos) {
  6401  	s.pp.Pos = pos
  6402  }
  6403  
  6404  // Br emits a single branch instruction and returns the instruction.
  6405  // Not all architectures need the returned instruction, but otherwise
  6406  // the boilerplate is common to all.
  6407  func (s *State) Br(op obj.As, target *ssa.Block) *obj.Prog {
  6408  	p := s.Prog(op)
  6409  	p.To.Type = obj.TYPE_BRANCH
  6410  	s.Branches = append(s.Branches, Branch{P: p, B: target})
  6411  	return p
  6412  }
  6413  
  6414  // DebugFriendlySetPosFrom adjusts Pos.IsStmt subject to heuristics
  6415  // that reduce "jumpy" line number churn when debugging.
  6416  // Spill/fill/copy instructions from the register allocator,
  6417  // phi functions, and instructions with a no-pos position
  6418  // are examples of instructions that can cause churn.
  6419  func (s *State) DebugFriendlySetPosFrom(v *ssa.Value) {
  6420  	switch v.Op {
  6421  	case ssa.OpPhi, ssa.OpCopy, ssa.OpLoadReg, ssa.OpStoreReg:
  6422  		// These are not statements
  6423  		s.SetPos(v.Pos.WithNotStmt())
  6424  	default:
  6425  		p := v.Pos
  6426  		if p != src.NoXPos {
  6427  			// If the position is defined, update the position.
  6428  			// Also convert default IsStmt to NotStmt; only
  6429  			// explicit statement boundaries should appear
  6430  			// in the generated code.
  6431  			if p.IsStmt() != src.PosIsStmt {
  6432  				if s.pp.Pos.IsStmt() == src.PosIsStmt && s.pp.Pos.SameFileAndLine(p) {
  6433  					// If s.pp.Pos already has a statement mark, then it was set here (below) for
  6434  					// the previous value.  If an actual instruction had been emitted for that
  6435  					// value, then the statement mark would have been reset.  Since the statement
  6436  					// mark of s.pp.Pos was not reset, this position (file/line) still needs a
  6437  					// statement mark on an instruction.  If file and line for this value are
  6438  					// the same as the previous value, then the first instruction for this
  6439  					// value will work to take the statement mark.  Return early to avoid
  6440  					// resetting the statement mark.
  6441  					//
  6442  					// The reset of s.pp.Pos occurs in (*Progs).Prog() -- if it emits
  6443  					// an instruction, and the instruction's statement mark was set,
  6444  					// and it is not one of the LosesStmtMark instructions,
  6445  					// then Prog() resets the statement mark on the (*Progs).Pos.
  6446  					return
  6447  				}
  6448  				p = p.WithNotStmt()
  6449  				// Calls use the pos attached to v, but copy the statement mark from State
  6450  			}
  6451  			s.SetPos(p)
  6452  		} else {
  6453  			s.SetPos(s.pp.Pos.WithNotStmt())
  6454  		}
  6455  	}
  6456  }
  6457  
  6458  // emit argument info (locations on stack) for traceback.
  6459  func emitArgInfo(e *ssafn, f *ssa.Func, pp *objw.Progs) {
  6460  	ft := e.curfn.Type()
  6461  	if ft.NumRecvs() == 0 && ft.NumParams() == 0 {
  6462  		return
  6463  	}
  6464  
  6465  	x := EmitArgInfo(e.curfn, f.OwnAux.ABIInfo())
  6466  	x.Set(obj.AttrContentAddressable, true)
  6467  	e.curfn.LSym.Func().ArgInfo = x
  6468  
  6469  	// Emit a funcdata pointing at the arg info data.
  6470  	p := pp.Prog(obj.AFUNCDATA)
  6471  	p.From.SetConst(rtabi.FUNCDATA_ArgInfo)
  6472  	p.To.Type = obj.TYPE_MEM
  6473  	p.To.Name = obj.NAME_EXTERN
  6474  	p.To.Sym = x
  6475  }
  6476  
  6477  // emit argument info (locations on stack) of f for traceback.
  6478  func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
  6479  	x := base.Ctxt.Lookup(fmt.Sprintf("%s.arginfo%d", f.LSym.Name, f.ABI))
  6480  	// NOTE: do not set ContentAddressable here. This may be referenced from
  6481  	// assembly code by name (in this case f is a declaration).
  6482  	// Instead, set it in emitArgInfo above.
  6483  
  6484  	PtrSize := int64(types.PtrSize)
  6485  	uintptrTyp := types.Types[types.TUINTPTR]
  6486  
  6487  	isAggregate := func(t *types.Type) bool {
  6488  		return t.IsStruct() || t.IsArray() || t.IsComplex() || t.IsInterface() || t.IsString() || t.IsSlice()
  6489  	}
  6490  
  6491  	wOff := 0
  6492  	n := 0
  6493  	writebyte := func(o uint8) { wOff = objw.Uint8(x, wOff, o) }
  6494  
  6495  	// Write one non-aggregate arg/field/element.
  6496  	write1 := func(sz, offset int64) {
  6497  		if offset >= rtabi.TraceArgsSpecial {
  6498  			writebyte(rtabi.TraceArgsOffsetTooLarge)
  6499  		} else {
  6500  			writebyte(uint8(offset))
  6501  			writebyte(uint8(sz))
  6502  		}
  6503  		n++
  6504  	}
  6505  
  6506  	// Visit t recursively and write it out.
  6507  	// Returns whether to continue visiting.
  6508  	var visitType func(baseOffset int64, t *types.Type, depth int) bool
  6509  	visitType = func(baseOffset int64, t *types.Type, depth int) bool {
  6510  		if n >= rtabi.TraceArgsLimit {
  6511  			writebyte(rtabi.TraceArgsDotdotdot)
  6512  			return false
  6513  		}
  6514  		if !isAggregate(t) {
  6515  			write1(t.Size(), baseOffset)
  6516  			return true
  6517  		}
  6518  		writebyte(rtabi.TraceArgsStartAgg)
  6519  		depth++
  6520  		if depth >= rtabi.TraceArgsMaxDepth {
  6521  			writebyte(rtabi.TraceArgsDotdotdot)
  6522  			writebyte(rtabi.TraceArgsEndAgg)
  6523  			n++
  6524  			return true
  6525  		}
  6526  		switch {
  6527  		case t.IsInterface(), t.IsString():
  6528  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6529  				visitType(baseOffset+PtrSize, uintptrTyp, depth)
  6530  		case t.IsSlice():
  6531  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6532  				visitType(baseOffset+PtrSize, uintptrTyp, depth) &&
  6533  				visitType(baseOffset+PtrSize*2, uintptrTyp, depth)
  6534  		case t.IsComplex():
  6535  			_ = visitType(baseOffset, types.FloatForComplex(t), depth) &&
  6536  				visitType(baseOffset+t.Size()/2, types.FloatForComplex(t), depth)
  6537  		case t.IsArray():
  6538  			if t.NumElem() == 0 {
  6539  				n++ // {} counts as a component
  6540  				break
  6541  			}
  6542  			for i := int64(0); i < t.NumElem(); i++ {
  6543  				if !visitType(baseOffset, t.Elem(), depth) {
  6544  					break
  6545  				}
  6546  				baseOffset += t.Elem().Size()
  6547  			}
  6548  		case t.IsStruct():
  6549  			if t.NumFields() == 0 {
  6550  				n++ // {} counts as a component
  6551  				break
  6552  			}
  6553  			for _, field := range t.Fields() {
  6554  				if !visitType(baseOffset+field.Offset, field.Type, depth) {
  6555  					break
  6556  				}
  6557  			}
  6558  		}
  6559  		writebyte(rtabi.TraceArgsEndAgg)
  6560  		return true
  6561  	}
  6562  
  6563  	start := 0
  6564  	if strings.Contains(f.LSym.Name, "[") {
  6565  		// Skip the dictionary argument - it is implicit and the user doesn't need to see it.
  6566  		start = 1
  6567  	}
  6568  
  6569  	for _, a := range abiInfo.InParams()[start:] {
  6570  		if !visitType(a.FrameOffset(abiInfo), a.Type, 0) {
  6571  			break
  6572  		}
  6573  	}
  6574  	writebyte(rtabi.TraceArgsEndSeq)
  6575  	if wOff > rtabi.TraceArgsMaxLen {
  6576  		base.Fatalf("ArgInfo too large")
  6577  	}
  6578  
  6579  	return x
  6580  }
  6581  
  6582  // for wrapper, emit info of wrapped function.
  6583  func emitWrappedFuncInfo(e *ssafn, pp *objw.Progs) {
  6584  	if base.Ctxt.Flag_linkshared {
  6585  		// Relative reference (SymPtrOff) to another shared object doesn't work.
  6586  		// Unfortunate.
  6587  		return
  6588  	}
  6589  
  6590  	wfn := e.curfn.WrappedFunc
  6591  	if wfn == nil {
  6592  		return
  6593  	}
  6594  
  6595  	wsym := wfn.Linksym()
  6596  	x := base.Ctxt.LookupInit(fmt.Sprintf("%s.wrapinfo", wsym.Name), func(x *obj.LSym) {
  6597  		objw.SymPtrOff(x, 0, wsym)
  6598  		x.Set(obj.AttrContentAddressable, true)
  6599  	})
  6600  	e.curfn.LSym.Func().WrapInfo = x
  6601  
  6602  	// Emit a funcdata pointing at the wrap info data.
  6603  	p := pp.Prog(obj.AFUNCDATA)
  6604  	p.From.SetConst(rtabi.FUNCDATA_WrapInfo)
  6605  	p.To.Type = obj.TYPE_MEM
  6606  	p.To.Name = obj.NAME_EXTERN
  6607  	p.To.Sym = x
  6608  }
  6609  
  6610  // genssa appends entries to pp for each instruction in f.
  6611  func genssa(f *ssa.Func, pp *objw.Progs) {
  6612  	var s State
  6613  	s.ABI = f.OwnAux.Fn.ABI()
  6614  
  6615  	e := f.Frontend().(*ssafn)
  6616  
  6617  	gatherPrintInfo := f.PrintOrHtmlSSA || ssa.GenssaDump[f.Name]
  6618  
  6619  	var lv *liveness.Liveness
  6620  	s.livenessMap, s.partLiveArgs, lv = liveness.Compute(e.curfn, f, e.stkptrsize, pp, gatherPrintInfo)
  6621  	emitArgInfo(e, f, pp)
  6622  	argLiveBlockMap, argLiveValueMap := liveness.ArgLiveness(e.curfn, f, pp)
  6623  
  6624  	openDeferInfo := e.curfn.LSym.Func().OpenCodedDeferInfo
  6625  	if openDeferInfo != nil {
  6626  		// This function uses open-coded defers -- write out the funcdata
  6627  		// info that we computed at the end of genssa.
  6628  		p := pp.Prog(obj.AFUNCDATA)
  6629  		p.From.SetConst(rtabi.FUNCDATA_OpenCodedDeferInfo)
  6630  		p.To.Type = obj.TYPE_MEM
  6631  		p.To.Name = obj.NAME_EXTERN
  6632  		p.To.Sym = openDeferInfo
  6633  	}
  6634  
  6635  	emitWrappedFuncInfo(e, pp)
  6636  
  6637  	// Remember where each block starts.
  6638  	s.bstart = make([]*obj.Prog, f.NumBlocks())
  6639  	s.pp = pp
  6640  	var progToValue map[*obj.Prog]*ssa.Value
  6641  	var progToBlock map[*obj.Prog]*ssa.Block
  6642  	var valueToProgAfter []*obj.Prog // The first Prog following computation of a value v; v is visible at this point.
  6643  	if gatherPrintInfo {
  6644  		progToValue = make(map[*obj.Prog]*ssa.Value, f.NumValues())
  6645  		progToBlock = make(map[*obj.Prog]*ssa.Block, f.NumBlocks())
  6646  		f.Logf("genssa %s\n", f.Name)
  6647  		progToBlock[s.pp.Next] = f.Blocks[0]
  6648  	}
  6649  
  6650  	if base.Ctxt.Flag_locationlists {
  6651  		if cap(f.Cache.ValueToProgAfter) < f.NumValues() {
  6652  			f.Cache.ValueToProgAfter = make([]*obj.Prog, f.NumValues())
  6653  		}
  6654  		valueToProgAfter = f.Cache.ValueToProgAfter[:f.NumValues()]
  6655  		clear(valueToProgAfter)
  6656  	}
  6657  
  6658  	// If the very first instruction is not tagged as a statement,
  6659  	// debuggers may attribute it to previous function in program.
  6660  	firstPos := src.NoXPos
  6661  	for _, v := range f.Entry.Values {
  6662  		if v.Pos.IsStmt() == src.PosIsStmt && v.Op != ssa.OpArg && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  6663  			firstPos = v.Pos
  6664  			v.Pos = firstPos.WithDefaultStmt()
  6665  			break
  6666  		}
  6667  	}
  6668  
  6669  	// inlMarks has an entry for each Prog that implements an inline mark.
  6670  	// It maps from that Prog to the global inlining id of the inlined body
  6671  	// which should unwind to this Prog's location.
  6672  	var inlMarks map[*obj.Prog]int32
  6673  	var inlMarkList []*obj.Prog
  6674  
  6675  	// inlMarksByPos maps from a (column 1) source position to the set of
  6676  	// Progs that are in the set above and have that source position.
  6677  	var inlMarksByPos map[src.XPos][]*obj.Prog
  6678  
  6679  	var argLiveIdx int = -1 // argument liveness info index
  6680  
  6681  	// These control cache line alignment; if the required portion of
  6682  	// a cache line is not available, then pad to obtain cache line
  6683  	// alignment.  Not implemented on all architectures, may not be
  6684  	// useful on all architectures.
  6685  	var hotAlign, hotRequire int64
  6686  
  6687  	if base.Debug.AlignHot > 0 {
  6688  		switch base.Ctxt.Arch.Name {
  6689  		// enable this on a case-by-case basis, with benchmarking.
  6690  		// currently shown:
  6691  		//   good for amd64
  6692  		//   not helpful for Apple Silicon
  6693  		//
  6694  		case "amd64", "386":
  6695  			// Align to 64 if 31 or fewer bytes remain in a cache line
  6696  			// benchmarks a little better than always aligning, and also
  6697  			// adds slightly less to the (PGO-compiled) binary size.
  6698  			hotAlign = 64
  6699  			hotRequire = 31
  6700  		}
  6701  	}
  6702  
  6703  	// Emit basic blocks
  6704  	for i, b := range f.Blocks {
  6705  
  6706  		s.lineRunStart = nil
  6707  		s.SetPos(s.pp.Pos.WithNotStmt()) // It needs a non-empty Pos, but cannot be a statement boundary (yet).
  6708  
  6709  		if hotAlign > 0 && b.Hotness&ssa.HotPgoInitial == ssa.HotPgoInitial {
  6710  			// So far this has only been shown profitable for PGO-hot loop headers.
  6711  			// The Hotness values allows distinctions between initial blocks that are "hot" or not, and "flow-in" or not.
  6712  			// Currently only the initial blocks of loops are tagged in this way;
  6713  			// there are no blocks tagged "pgo-hot" that are not also tagged "initial".
  6714  			// TODO more heuristics, more architectures.
  6715  			p := s.pp.Prog(obj.APCALIGNMAX)
  6716  			p.From.SetConst(hotAlign)
  6717  			p.To.SetConst(hotRequire)
  6718  		}
  6719  
  6720  		s.bstart[b.ID] = s.pp.Next
  6721  
  6722  		if idx, ok := argLiveBlockMap[b.ID]; ok && idx != argLiveIdx {
  6723  			argLiveIdx = idx
  6724  			p := s.pp.Prog(obj.APCDATA)
  6725  			p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  6726  			p.To.SetConst(int64(idx))
  6727  		}
  6728  
  6729  		// Emit values in block
  6730  		Arch.SSAMarkMoves(&s, b)
  6731  		for _, v := range b.Values {
  6732  			x := s.pp.Next
  6733  			s.DebugFriendlySetPosFrom(v)
  6734  
  6735  			if v.Op.ResultInArg0() && v.ResultReg() != v.Args[0].Reg() {
  6736  				v.Fatalf("input[0] and output not in same register %s", v.LongString())
  6737  			}
  6738  
  6739  			switch v.Op {
  6740  			case ssa.OpInitMem:
  6741  				// memory arg needs no code
  6742  			case ssa.OpArg:
  6743  				// input args need no code
  6744  			case ssa.OpSP, ssa.OpSB:
  6745  				// nothing to do
  6746  			case ssa.OpSelect0, ssa.OpSelect1, ssa.OpSelectN, ssa.OpMakeResult:
  6747  				// nothing to do
  6748  			case ssa.OpGetG:
  6749  				// nothing to do when there's a g register,
  6750  				// and checkLower complains if there's not
  6751  			case ssa.OpVarDef, ssa.OpVarLive, ssa.OpKeepAlive, ssa.OpWBend:
  6752  				// nothing to do; already used by liveness
  6753  			case ssa.OpPhi:
  6754  				CheckLoweredPhi(v)
  6755  			case ssa.OpConvert:
  6756  				// nothing to do; no-op conversion for liveness
  6757  				if v.Args[0].Reg() != v.Reg() {
  6758  					v.Fatalf("OpConvert should be a no-op: %s; %s", v.Args[0].LongString(), v.LongString())
  6759  				}
  6760  			case ssa.OpInlMark:
  6761  				p := Arch.Ginsnop(s.pp)
  6762  				if inlMarks == nil {
  6763  					inlMarks = map[*obj.Prog]int32{}
  6764  					inlMarksByPos = map[src.XPos][]*obj.Prog{}
  6765  				}
  6766  				inlMarks[p] = v.AuxInt32()
  6767  				inlMarkList = append(inlMarkList, p)
  6768  				pos := v.Pos.AtColumn1()
  6769  				inlMarksByPos[pos] = append(inlMarksByPos[pos], p)
  6770  				firstPos = src.NoXPos
  6771  
  6772  			default:
  6773  				// Special case for first line in function; move it to the start (which cannot be a register-valued instruction)
  6774  				if firstPos != src.NoXPos && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  6775  					s.SetPos(firstPos)
  6776  					firstPos = src.NoXPos
  6777  				}
  6778  				// Attach this safe point to the next
  6779  				// instruction.
  6780  				s.pp.NextLive = s.livenessMap.Get(v)
  6781  				s.pp.NextUnsafe = s.livenessMap.GetUnsafe(v)
  6782  
  6783  				// let the backend handle it
  6784  				Arch.SSAGenValue(&s, v)
  6785  			}
  6786  
  6787  			if idx, ok := argLiveValueMap[v.ID]; ok && idx != argLiveIdx {
  6788  				argLiveIdx = idx
  6789  				p := s.pp.Prog(obj.APCDATA)
  6790  				p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  6791  				p.To.SetConst(int64(idx))
  6792  			}
  6793  
  6794  			if base.Ctxt.Flag_locationlists {
  6795  				valueToProgAfter[v.ID] = s.pp.Next
  6796  			}
  6797  
  6798  			if gatherPrintInfo {
  6799  				for ; x != s.pp.Next; x = x.Link {
  6800  					progToValue[x] = v
  6801  				}
  6802  			}
  6803  		}
  6804  		// If this is an empty infinite loop, stick a hardware NOP in there so that debuggers are less confused.
  6805  		if s.bstart[b.ID] == s.pp.Next && len(b.Succs) == 1 && b.Succs[0].Block() == b {
  6806  			p := Arch.Ginsnop(s.pp)
  6807  			p.Pos = p.Pos.WithIsStmt()
  6808  			if b.Pos == src.NoXPos {
  6809  				b.Pos = p.Pos // It needs a file, otherwise a no-file non-zero line causes confusion.  See #35652.
  6810  				if b.Pos == src.NoXPos {
  6811  					b.Pos = s.pp.Text.Pos // Sometimes p.Pos is empty.  See #35695.
  6812  				}
  6813  			}
  6814  			b.Pos = b.Pos.WithBogusLine() // Debuggers are not good about infinite loops, force a change in line number
  6815  		}
  6816  
  6817  		// Set unsafe mark for any end-of-block generated instructions
  6818  		// (normally, conditional or unconditional branches).
  6819  		// This is particularly important for empty blocks, as there
  6820  		// are no values to inherit the unsafe mark from.
  6821  		s.pp.NextUnsafe = s.livenessMap.GetUnsafeBlock(b)
  6822  
  6823  		// Emit control flow instructions for block
  6824  		var next *ssa.Block
  6825  		if i < len(f.Blocks)-1 && base.Flag.N == 0 {
  6826  			// If -N, leave next==nil so every block with successors
  6827  			// ends in a JMP (except call blocks - plive doesn't like
  6828  			// select{send,recv} followed by a JMP call).  Helps keep
  6829  			// line numbers for otherwise empty blocks.
  6830  			next = f.Blocks[i+1]
  6831  		}
  6832  		x := s.pp.Next
  6833  		s.SetPos(b.Pos)
  6834  		Arch.SSAGenBlock(&s, b, next)
  6835  		if gatherPrintInfo {
  6836  			for ; x != s.pp.Next; x = x.Link {
  6837  				progToBlock[x] = b
  6838  			}
  6839  		}
  6840  	}
  6841  	if f.Blocks[len(f.Blocks)-1].Kind == ssa.BlockExit {
  6842  		// We need the return address of a panic call to
  6843  		// still be inside the function in question. So if
  6844  		// it ends in a call which doesn't return, add a
  6845  		// nop (which will never execute) after the call.
  6846  		Arch.Ginsnop(s.pp)
  6847  	}
  6848  	if openDeferInfo != nil {
  6849  		// When doing open-coded defers, generate a disconnected call to
  6850  		// deferreturn and a return. This will be used to during panic
  6851  		// recovery to unwind the stack and return back to the runtime.
  6852  
  6853  		// Note that this exit code doesn't work if a return parameter
  6854  		// is heap-allocated, but open defers aren't enabled in that case.
  6855  
  6856  		// TODO either make this handle heap-allocated return parameters or reuse the other-defers general-purpose code path.
  6857  		s.pp.NextLive = s.livenessMap.DeferReturn
  6858  		p := s.pp.Prog(obj.ACALL)
  6859  		p.To.Type = obj.TYPE_MEM
  6860  		p.To.Name = obj.NAME_EXTERN
  6861  		p.To.Sym = ir.Syms.Deferreturn
  6862  
  6863  		// Load results into registers. So when a deferred function
  6864  		// recovers a panic, it will return to caller with right results.
  6865  		// The results are already in memory, because they are not SSA'd
  6866  		// when the function has defers (see canSSAName).
  6867  		for _, o := range f.OwnAux.ABIInfo().OutParams() {
  6868  			n := o.Name
  6869  			rts, offs := o.RegisterTypesAndOffsets()
  6870  			for i := range o.Registers {
  6871  				Arch.LoadRegResult(&s, f, rts[i], ssa.ObjRegForAbiReg(o.Registers[i], f.Config), n, offs[i])
  6872  			}
  6873  		}
  6874  
  6875  		s.pp.Prog(obj.ARET)
  6876  	}
  6877  
  6878  	if inlMarks != nil {
  6879  		hasCall := false
  6880  
  6881  		// We have some inline marks. Try to find other instructions we're
  6882  		// going to emit anyway, and use those instructions instead of the
  6883  		// inline marks.
  6884  		for p := s.pp.Text; p != nil; p = p.Link {
  6885  			if p.As == obj.ANOP || p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT ||
  6886  				p.As == obj.APCALIGN || p.As == obj.APCALIGNMAX || Arch.LinkArch.Family == sys.Wasm {
  6887  				// Don't use 0-sized instructions as inline marks, because we need
  6888  				// to identify inline mark instructions by pc offset.
  6889  				// (Some of these instructions are sometimes zero-sized, sometimes not.
  6890  				// We must not use anything that even might be zero-sized.)
  6891  				// TODO: are there others?
  6892  				continue
  6893  			}
  6894  			if _, ok := inlMarks[p]; ok {
  6895  				// Don't use inline marks themselves. We don't know
  6896  				// whether they will be zero-sized or not yet.
  6897  				continue
  6898  			}
  6899  			if p.As == obj.ACALL || p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
  6900  				hasCall = true
  6901  			}
  6902  			pos := p.Pos.AtColumn1()
  6903  			marks := inlMarksByPos[pos]
  6904  			if len(marks) == 0 {
  6905  				continue
  6906  			}
  6907  			for _, m := range marks {
  6908  				// We found an instruction with the same source position as
  6909  				// some of the inline marks.
  6910  				// Use this instruction instead.
  6911  				p.Pos = p.Pos.WithIsStmt() // promote position to a statement
  6912  				s.pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[m])
  6913  				// Make the inline mark a real nop, so it doesn't generate any code.
  6914  				m.As = obj.ANOP
  6915  				m.Pos = src.NoXPos
  6916  				m.From = obj.Addr{}
  6917  				m.To = obj.Addr{}
  6918  			}
  6919  			delete(inlMarksByPos, pos)
  6920  		}
  6921  		// Any unmatched inline marks now need to be added to the inlining tree (and will generate a nop instruction).
  6922  		for _, p := range inlMarkList {
  6923  			if p.As != obj.ANOP {
  6924  				s.pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[p])
  6925  			}
  6926  		}
  6927  
  6928  		if e.stksize == 0 && !hasCall {
  6929  			// Frameless leaf function. It doesn't need any preamble,
  6930  			// so make sure its first instruction isn't from an inlined callee.
  6931  			// If it is, add a nop at the start of the function with a position
  6932  			// equal to the start of the function.
  6933  			// This ensures that runtime.FuncForPC(uintptr(reflect.ValueOf(fn).Pointer())).Name()
  6934  			// returns the right answer. See issue 58300.
  6935  			for p := s.pp.Text; p != nil; p = p.Link {
  6936  				if p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT || p.As == obj.ANOP {
  6937  					continue
  6938  				}
  6939  				if base.Ctxt.PosTable.Pos(p.Pos).Base().InliningIndex() >= 0 {
  6940  					// Make a real (not 0-sized) nop.
  6941  					nop := Arch.Ginsnop(s.pp)
  6942  					nop.Pos = e.curfn.Pos().WithIsStmt()
  6943  
  6944  					// Unfortunately, Ginsnop puts the instruction at the
  6945  					// end of the list. Move it up to just before p.
  6946  
  6947  					// Unlink from the current list.
  6948  					for x := s.pp.Text; x != nil; x = x.Link {
  6949  						if x.Link == nop {
  6950  							x.Link = nop.Link
  6951  							break
  6952  						}
  6953  					}
  6954  					// Splice in right before p.
  6955  					for x := s.pp.Text; x != nil; x = x.Link {
  6956  						if x.Link == p {
  6957  							nop.Link = p
  6958  							x.Link = nop
  6959  							break
  6960  						}
  6961  					}
  6962  				}
  6963  				break
  6964  			}
  6965  		}
  6966  	}
  6967  
  6968  	if base.Ctxt.Flag_locationlists {
  6969  		var debugInfo *ssa.FuncDebug
  6970  		debugInfo = e.curfn.DebugInfo.(*ssa.FuncDebug)
  6971  		// Save off entry ID in case we need it later for DWARF generation
  6972  		// for return values promoted to the heap.
  6973  		debugInfo.EntryID = f.Entry.ID
  6974  		if e.curfn.ABI == obj.ABIInternal && base.Flag.N != 0 {
  6975  			ssa.BuildFuncDebugNoOptimized(base.Ctxt, f, base.Debug.LocationLists > 1, StackOffset, debugInfo)
  6976  		} else {
  6977  			ssa.BuildFuncDebug(base.Ctxt, f, base.Debug.LocationLists, StackOffset, debugInfo)
  6978  		}
  6979  		bstart := s.bstart
  6980  		idToIdx := make([]int, f.NumBlocks())
  6981  		for i, b := range f.Blocks {
  6982  			idToIdx[b.ID] = i
  6983  		}
  6984  		// Register a callback that will be used later to fill in PCs into location
  6985  		// lists. At the moment, Prog.Pc is a sequence number; it's not a real PC
  6986  		// until after assembly, so the translation needs to be deferred.
  6987  		debugInfo.GetPC = func(b, v ssa.ID) int64 {
  6988  			switch v {
  6989  			case ssa.BlockStart.ID:
  6990  				if b == f.Entry.ID {
  6991  					return 0 // Start at the very beginning, at the assembler-generated prologue.
  6992  					// this should only happen for function args (ssa.OpArg)
  6993  				}
  6994  				return bstart[b].Pc
  6995  			case ssa.BlockEnd.ID:
  6996  				blk := f.Blocks[idToIdx[b]]
  6997  				nv := len(blk.Values)
  6998  				return valueToProgAfter[blk.Values[nv-1].ID].Pc
  6999  			case ssa.FuncEnd.ID:
  7000  				return e.curfn.LSym.Size
  7001  			default:
  7002  				return valueToProgAfter[v].Pc
  7003  			}
  7004  		}
  7005  	}
  7006  
  7007  	// Resolve branches, and relax DefaultStmt into NotStmt
  7008  	for _, br := range s.Branches {
  7009  		br.P.To.SetTarget(s.bstart[br.B.ID])
  7010  		if br.P.Pos.IsStmt() != src.PosIsStmt {
  7011  			br.P.Pos = br.P.Pos.WithNotStmt()
  7012  		} else if v0 := br.B.FirstPossibleStmtValue(); v0 != nil && v0.Pos.Line() == br.P.Pos.Line() && v0.Pos.IsStmt() == src.PosIsStmt {
  7013  			br.P.Pos = br.P.Pos.WithNotStmt()
  7014  		}
  7015  
  7016  	}
  7017  
  7018  	// Resolve jump table destinations.
  7019  	for _, jt := range s.JumpTables {
  7020  		// Convert from *Block targets to *Prog targets.
  7021  		targets := make([]*obj.Prog, len(jt.Succs))
  7022  		for i, e := range jt.Succs {
  7023  			targets[i] = s.bstart[e.Block().ID]
  7024  		}
  7025  		// Add to list of jump tables to be resolved at assembly time.
  7026  		// The assembler converts from *Prog entries to absolute addresses
  7027  		// once it knows instruction byte offsets.
  7028  		fi := s.pp.CurFunc.LSym.Func()
  7029  		fi.JumpTables = append(fi.JumpTables, obj.JumpTable{Sym: jt.Aux.(*obj.LSym), Targets: targets})
  7030  	}
  7031  
  7032  	if e.log { // spew to stdout
  7033  		filename := ""
  7034  		for p := s.pp.Text; p != nil; p = p.Link {
  7035  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7036  				filename = p.InnermostFilename()
  7037  				f.Logf("# %s\n", filename)
  7038  			}
  7039  
  7040  			var s string
  7041  			if v, ok := progToValue[p]; ok {
  7042  				s = v.String()
  7043  			} else if b, ok := progToBlock[p]; ok {
  7044  				s = b.String()
  7045  			} else {
  7046  				s = "   " // most value and branch strings are 2-3 characters long
  7047  			}
  7048  			f.Logf(" %-6s\t%.5d (%s)\t%s\n", s, p.Pc, p.InnermostLineNumber(), p.InstructionString())
  7049  		}
  7050  	}
  7051  	if f.HTMLWriter != nil { // spew to ssa.html
  7052  		var buf strings.Builder
  7053  		buf.WriteString("<code>")
  7054  		buf.WriteString("<dl class=\"ssa-gen\">")
  7055  		filename := ""
  7056  
  7057  		liveness := lv.Format(nil)
  7058  		if liveness != "" {
  7059  			buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7060  			buf.WriteString(html.EscapeString("# " + liveness))
  7061  			buf.WriteString("</dd>")
  7062  		}
  7063  
  7064  		for p := s.pp.Text; p != nil; p = p.Link {
  7065  			// Don't spam every line with the file name, which is often huge.
  7066  			// Only print changes, and "unknown" is not a change.
  7067  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7068  				filename = p.InnermostFilename()
  7069  				buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7070  				buf.WriteString(html.EscapeString("# " + filename))
  7071  				buf.WriteString("</dd>")
  7072  			}
  7073  
  7074  			buf.WriteString("<dt class=\"ssa-prog-src\">")
  7075  			if v, ok := progToValue[p]; ok {
  7076  
  7077  				// Prefix calls with their liveness, if any
  7078  				if p.As != obj.APCDATA {
  7079  					if liveness := lv.Format(v); liveness != "" {
  7080  						// Steal this line, and restart a line
  7081  						buf.WriteString("</dt><dd class=\"ssa-prog\">")
  7082  						buf.WriteString(html.EscapeString("# " + liveness))
  7083  						buf.WriteString("</dd>")
  7084  						// restarting a line
  7085  						buf.WriteString("<dt class=\"ssa-prog-src\">")
  7086  					}
  7087  				}
  7088  
  7089  				buf.WriteString(v.HTML())
  7090  			} else if b, ok := progToBlock[p]; ok {
  7091  				buf.WriteString("<b>" + b.HTML() + "</b>")
  7092  			}
  7093  			buf.WriteString("</dt>")
  7094  			buf.WriteString("<dd class=\"ssa-prog\">")
  7095  			fmt.Fprintf(&buf, "%.5d <span class=\"l%v line-number\">(%s)</span> %s", p.Pc, p.InnermostLineNumber(), p.InnermostLineNumberHTML(), html.EscapeString(p.InstructionString()))
  7096  			buf.WriteString("</dd>")
  7097  		}
  7098  		buf.WriteString("</dl>")
  7099  		buf.WriteString("</code>")
  7100  		f.HTMLWriter.WriteColumn("genssa", "genssa", "ssa-prog", buf.String())
  7101  	}
  7102  	if ssa.GenssaDump[f.Name] {
  7103  		fi := f.DumpFileForPhase("genssa")
  7104  		if fi != nil {
  7105  
  7106  			// inliningDiffers if any filename changes or if any line number except the innermost (last index) changes.
  7107  			inliningDiffers := func(a, b []src.Pos) bool {
  7108  				if len(a) != len(b) {
  7109  					return true
  7110  				}
  7111  				for i := range a {
  7112  					if a[i].Filename() != b[i].Filename() {
  7113  						return true
  7114  					}
  7115  					if i != len(a)-1 && a[i].Line() != b[i].Line() {
  7116  						return true
  7117  					}
  7118  				}
  7119  				return false
  7120  			}
  7121  
  7122  			var allPosOld []src.Pos
  7123  			var allPos []src.Pos
  7124  
  7125  			for p := s.pp.Text; p != nil; p = p.Link {
  7126  				if p.Pos.IsKnown() {
  7127  					allPos = allPos[:0]
  7128  					p.Ctxt.AllPos(p.Pos, func(pos src.Pos) { allPos = append(allPos, pos) })
  7129  					if inliningDiffers(allPos, allPosOld) {
  7130  						for _, pos := range allPos {
  7131  							fmt.Fprintf(fi, "# %s:%d\n", pos.Filename(), pos.Line())
  7132  						}
  7133  						allPos, allPosOld = allPosOld, allPos // swap, not copy, so that they do not share slice storage.
  7134  					}
  7135  				}
  7136  
  7137  				var s string
  7138  				if v, ok := progToValue[p]; ok {
  7139  					s = v.String()
  7140  				} else if b, ok := progToBlock[p]; ok {
  7141  					s = b.String()
  7142  				} else {
  7143  					s = "   " // most value and branch strings are 2-3 characters long
  7144  				}
  7145  				fmt.Fprintf(fi, " %-6s\t%.5d %s\t%s\n", s, p.Pc, ssa.StmtString(p.Pos), p.InstructionString())
  7146  			}
  7147  			fi.Close()
  7148  		}
  7149  	}
  7150  
  7151  	defframe(&s, e, f)
  7152  
  7153  	f.HTMLWriter.Close()
  7154  	f.HTMLWriter = nil
  7155  }
  7156  
  7157  func defframe(s *State, e *ssafn, f *ssa.Func) {
  7158  	pp := s.pp
  7159  
  7160  	s.maxarg = types.RoundUp(s.maxarg, e.stkalign)
  7161  	frame := s.maxarg + e.stksize
  7162  	if Arch.PadFrame != nil {
  7163  		frame = Arch.PadFrame(frame)
  7164  	}
  7165  
  7166  	// Fill in argument and frame size.
  7167  	pp.Text.To.Type = obj.TYPE_TEXTSIZE
  7168  	pp.Text.To.Val = int32(types.RoundUp(f.OwnAux.ArgWidth(), int64(types.RegSize)))
  7169  	pp.Text.To.Offset = frame
  7170  
  7171  	p := pp.Text
  7172  
  7173  	// Insert code to spill argument registers if the named slot may be partially
  7174  	// live. That is, the named slot is considered live by liveness analysis,
  7175  	// (because a part of it is live), but we may not spill all parts into the
  7176  	// slot. This can only happen with aggregate-typed arguments that are SSA-able
  7177  	// and not address-taken (for non-SSA-able or address-taken arguments we always
  7178  	// spill upfront).
  7179  	// Note: spilling is unnecessary in the -N/no-optimize case, since all values
  7180  	// will be considered non-SSAable and spilled up front.
  7181  	// TODO(register args) Make liveness more fine-grained to that partial spilling is okay.
  7182  	if f.OwnAux.ABIInfo().InRegistersUsed() != 0 && base.Flag.N == 0 {
  7183  		// First, see if it is already spilled before it may be live. Look for a spill
  7184  		// in the entry block up to the first safepoint.
  7185  		type nameOff struct {
  7186  			n   *ir.Name
  7187  			off int64
  7188  		}
  7189  		partLiveArgsSpilled := make(map[nameOff]bool)
  7190  		for _, v := range f.Entry.Values {
  7191  			if v.Op.IsCall() {
  7192  				break
  7193  			}
  7194  			if v.Op != ssa.OpStoreReg || v.Args[0].Op != ssa.OpArgIntReg {
  7195  				continue
  7196  			}
  7197  			n, off := ssa.AutoVar(v)
  7198  			if n.Class != ir.PPARAM || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] {
  7199  				continue
  7200  			}
  7201  			partLiveArgsSpilled[nameOff{n, off}] = true
  7202  		}
  7203  
  7204  		// Then, insert code to spill registers if not already.
  7205  		for _, a := range f.OwnAux.ABIInfo().InParams() {
  7206  			n := a.Name
  7207  			if n == nil || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] || len(a.Registers) <= 1 {
  7208  				continue
  7209  			}
  7210  			rts, offs := a.RegisterTypesAndOffsets()
  7211  			for i := range a.Registers {
  7212  				if !rts[i].HasPointers() {
  7213  					continue
  7214  				}
  7215  				if partLiveArgsSpilled[nameOff{n, offs[i]}] {
  7216  					continue // already spilled
  7217  				}
  7218  				reg := ssa.ObjRegForAbiReg(a.Registers[i], f.Config)
  7219  				p = Arch.SpillArgReg(pp, p, f, rts[i], reg, n, offs[i])
  7220  			}
  7221  		}
  7222  	}
  7223  
  7224  	// Insert code to zero ambiguously live variables so that the
  7225  	// garbage collector only sees initialized values when it
  7226  	// looks for pointers.
  7227  	var lo, hi int64
  7228  
  7229  	// Opaque state for backend to use. Current backends use it to
  7230  	// keep track of which helper registers have been zeroed.
  7231  	var state uint32
  7232  
  7233  	// Iterate through declarations. Autos are sorted in decreasing
  7234  	// frame offset order.
  7235  	for _, n := range e.curfn.Dcl {
  7236  		if !n.Needzero() {
  7237  			continue
  7238  		}
  7239  		if n.Class != ir.PAUTO {
  7240  			e.Fatalf(n.Pos(), "needzero class %d", n.Class)
  7241  		}
  7242  		if n.Type().Size()%int64(types.PtrSize) != 0 || n.FrameOffset()%int64(types.PtrSize) != 0 || n.Type().Size() == 0 {
  7243  			e.Fatalf(n.Pos(), "var %L has size %d offset %d", n, n.Type().Size(), n.Offset_)
  7244  		}
  7245  
  7246  		if lo != hi && n.FrameOffset()+n.Type().Size() >= lo-int64(2*types.RegSize) {
  7247  			// Merge with range we already have.
  7248  			lo = n.FrameOffset()
  7249  			continue
  7250  		}
  7251  
  7252  		// Zero old range
  7253  		p = Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7254  
  7255  		// Set new range.
  7256  		lo = n.FrameOffset()
  7257  		hi = lo + n.Type().Size()
  7258  	}
  7259  
  7260  	// Zero final range.
  7261  	Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7262  }
  7263  
  7264  // For generating consecutive jump instructions to model a specific branching
  7265  type IndexJump struct {
  7266  	Jump  obj.As
  7267  	Index int
  7268  }
  7269  
  7270  func (s *State) oneJump(b *ssa.Block, jump *IndexJump) {
  7271  	p := s.Br(jump.Jump, b.Succs[jump.Index].Block())
  7272  	p.Pos = b.Pos
  7273  }
  7274  
  7275  // CombJump generates combinational instructions (2 at present) for a block jump,
  7276  // thereby the behaviour of non-standard condition codes could be simulated
  7277  func (s *State) CombJump(b, next *ssa.Block, jumps *[2][2]IndexJump) {
  7278  	switch next {
  7279  	case b.Succs[0].Block():
  7280  		s.oneJump(b, &jumps[0][0])
  7281  		s.oneJump(b, &jumps[0][1])
  7282  	case b.Succs[1].Block():
  7283  		s.oneJump(b, &jumps[1][0])
  7284  		s.oneJump(b, &jumps[1][1])
  7285  	default:
  7286  		var q *obj.Prog
  7287  		if b.Likely != ssa.BranchUnlikely {
  7288  			s.oneJump(b, &jumps[1][0])
  7289  			s.oneJump(b, &jumps[1][1])
  7290  			q = s.Br(obj.AJMP, b.Succs[1].Block())
  7291  		} else {
  7292  			s.oneJump(b, &jumps[0][0])
  7293  			s.oneJump(b, &jumps[0][1])
  7294  			q = s.Br(obj.AJMP, b.Succs[0].Block())
  7295  		}
  7296  		q.Pos = b.Pos
  7297  	}
  7298  }
  7299  
  7300  // AddAux adds the offset in the aux fields (AuxInt and Aux) of v to a.
  7301  func AddAux(a *obj.Addr, v *ssa.Value) {
  7302  	AddAux2(a, v, v.AuxInt)
  7303  }
  7304  func AddAux2(a *obj.Addr, v *ssa.Value, offset int64) {
  7305  	if a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR {
  7306  		v.Fatalf("bad AddAux addr %v", a)
  7307  	}
  7308  	// add integer offset
  7309  	a.Offset += offset
  7310  
  7311  	// If no additional symbol offset, we're done.
  7312  	if v.Aux == nil {
  7313  		return
  7314  	}
  7315  	// Add symbol's offset from its base register.
  7316  	switch n := v.Aux.(type) {
  7317  	case *ssa.AuxCall:
  7318  		a.Name = obj.NAME_EXTERN
  7319  		a.Sym = n.Fn
  7320  	case *obj.LSym:
  7321  		a.Name = obj.NAME_EXTERN
  7322  		a.Sym = n
  7323  	case *ir.Name:
  7324  		if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7325  			a.Name = obj.NAME_PARAM
  7326  		} else {
  7327  			a.Name = obj.NAME_AUTO
  7328  		}
  7329  		a.Sym = n.Linksym()
  7330  		a.Offset += n.FrameOffset()
  7331  	default:
  7332  		v.Fatalf("aux in %s not implemented %#v", v, v.Aux)
  7333  	}
  7334  }
  7335  
  7336  // extendIndex extends v to a full int width.
  7337  // panic with the given kind if v does not fit in an int (only on 32-bit archs).
  7338  func (s *state) extendIndex(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  7339  	size := idx.Type.Size()
  7340  	if size == s.config.PtrSize {
  7341  		return idx
  7342  	}
  7343  	if size > s.config.PtrSize {
  7344  		// truncate 64-bit indexes on 32-bit pointer archs. Test the
  7345  		// high word and branch to out-of-bounds failure if it is not 0.
  7346  		var lo *ssa.Value
  7347  		if idx.Type.IsSigned() {
  7348  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TINT], idx)
  7349  		} else {
  7350  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TUINT], idx)
  7351  		}
  7352  		if bounded || base.Flag.B != 0 {
  7353  			return lo
  7354  		}
  7355  		bNext := s.f.NewBlock(ssa.BlockPlain)
  7356  		bPanic := s.f.NewBlock(ssa.BlockExit)
  7357  		hi := s.newValue1(ssa.OpInt64Hi, types.Types[types.TUINT32], idx)
  7358  		cmp := s.newValue2(ssa.OpEq32, types.Types[types.TBOOL], hi, s.constInt32(types.Types[types.TUINT32], 0))
  7359  		if !idx.Type.IsSigned() {
  7360  			switch kind {
  7361  			case ssa.BoundsIndex:
  7362  				kind = ssa.BoundsIndexU
  7363  			case ssa.BoundsSliceAlen:
  7364  				kind = ssa.BoundsSliceAlenU
  7365  			case ssa.BoundsSliceAcap:
  7366  				kind = ssa.BoundsSliceAcapU
  7367  			case ssa.BoundsSliceB:
  7368  				kind = ssa.BoundsSliceBU
  7369  			case ssa.BoundsSlice3Alen:
  7370  				kind = ssa.BoundsSlice3AlenU
  7371  			case ssa.BoundsSlice3Acap:
  7372  				kind = ssa.BoundsSlice3AcapU
  7373  			case ssa.BoundsSlice3B:
  7374  				kind = ssa.BoundsSlice3BU
  7375  			case ssa.BoundsSlice3C:
  7376  				kind = ssa.BoundsSlice3CU
  7377  			}
  7378  		}
  7379  		b := s.endBlock()
  7380  		b.Kind = ssa.BlockIf
  7381  		b.SetControl(cmp)
  7382  		b.Likely = ssa.BranchLikely
  7383  		b.AddEdgeTo(bNext)
  7384  		b.AddEdgeTo(bPanic)
  7385  
  7386  		s.startBlock(bPanic)
  7387  		mem := s.newValue4I(ssa.OpPanicExtend, types.TypeMem, int64(kind), hi, lo, len, s.mem())
  7388  		s.endBlock().SetControl(mem)
  7389  		s.startBlock(bNext)
  7390  
  7391  		return lo
  7392  	}
  7393  
  7394  	// Extend value to the required size
  7395  	var op ssa.Op
  7396  	if idx.Type.IsSigned() {
  7397  		switch 10*size + s.config.PtrSize {
  7398  		case 14:
  7399  			op = ssa.OpSignExt8to32
  7400  		case 18:
  7401  			op = ssa.OpSignExt8to64
  7402  		case 24:
  7403  			op = ssa.OpSignExt16to32
  7404  		case 28:
  7405  			op = ssa.OpSignExt16to64
  7406  		case 48:
  7407  			op = ssa.OpSignExt32to64
  7408  		default:
  7409  			s.Fatalf("bad signed index extension %s", idx.Type)
  7410  		}
  7411  	} else {
  7412  		switch 10*size + s.config.PtrSize {
  7413  		case 14:
  7414  			op = ssa.OpZeroExt8to32
  7415  		case 18:
  7416  			op = ssa.OpZeroExt8to64
  7417  		case 24:
  7418  			op = ssa.OpZeroExt16to32
  7419  		case 28:
  7420  			op = ssa.OpZeroExt16to64
  7421  		case 48:
  7422  			op = ssa.OpZeroExt32to64
  7423  		default:
  7424  			s.Fatalf("bad unsigned index extension %s", idx.Type)
  7425  		}
  7426  	}
  7427  	return s.newValue1(op, types.Types[types.TINT], idx)
  7428  }
  7429  
  7430  // CheckLoweredPhi checks that regalloc and stackalloc correctly handled phi values.
  7431  // Called during ssaGenValue.
  7432  func CheckLoweredPhi(v *ssa.Value) {
  7433  	if v.Op != ssa.OpPhi {
  7434  		v.Fatalf("CheckLoweredPhi called with non-phi value: %v", v.LongString())
  7435  	}
  7436  	if v.Type.IsMemory() {
  7437  		return
  7438  	}
  7439  	f := v.Block.Func
  7440  	loc := f.RegAlloc[v.ID]
  7441  	for _, a := range v.Args {
  7442  		if aloc := f.RegAlloc[a.ID]; aloc != loc { // TODO: .Equal() instead?
  7443  			v.Fatalf("phi arg at different location than phi: %v @ %s, but arg %v @ %s\n%s\n", v, loc, a, aloc, v.Block.Func)
  7444  		}
  7445  	}
  7446  }
  7447  
  7448  // CheckLoweredGetClosurePtr checks that v is the first instruction in the function's entry block,
  7449  // except for incoming in-register arguments.
  7450  // The output of LoweredGetClosurePtr is generally hardwired to the correct register.
  7451  // That register contains the closure pointer on closure entry.
  7452  func CheckLoweredGetClosurePtr(v *ssa.Value) {
  7453  	entry := v.Block.Func.Entry
  7454  	if entry != v.Block {
  7455  		base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7456  	}
  7457  	for _, w := range entry.Values {
  7458  		if w == v {
  7459  			break
  7460  		}
  7461  		switch w.Op {
  7462  		case ssa.OpArgIntReg, ssa.OpArgFloatReg:
  7463  			// okay
  7464  		default:
  7465  			base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7466  		}
  7467  	}
  7468  }
  7469  
  7470  // CheckArgReg ensures that v is in the function's entry block.
  7471  func CheckArgReg(v *ssa.Value) {
  7472  	entry := v.Block.Func.Entry
  7473  	if entry != v.Block {
  7474  		base.Fatalf("in %s, badly placed ArgIReg or ArgFReg: %v %v", v.Block.Func.Name, v.Block, v)
  7475  	}
  7476  }
  7477  
  7478  func AddrAuto(a *obj.Addr, v *ssa.Value) {
  7479  	n, off := ssa.AutoVar(v)
  7480  	a.Type = obj.TYPE_MEM
  7481  	a.Sym = n.Linksym()
  7482  	a.Reg = int16(Arch.REGSP)
  7483  	a.Offset = n.FrameOffset() + off
  7484  	if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7485  		a.Name = obj.NAME_PARAM
  7486  	} else {
  7487  		a.Name = obj.NAME_AUTO
  7488  	}
  7489  }
  7490  
  7491  // Call returns a new CALL instruction for the SSA value v.
  7492  // It uses PrepareCall to prepare the call.
  7493  func (s *State) Call(v *ssa.Value) *obj.Prog {
  7494  	pPosIsStmt := s.pp.Pos.IsStmt() // The statement-ness fo the call comes from ssaGenState
  7495  	s.PrepareCall(v)
  7496  
  7497  	p := s.Prog(obj.ACALL)
  7498  	if pPosIsStmt == src.PosIsStmt {
  7499  		p.Pos = v.Pos.WithIsStmt()
  7500  	} else {
  7501  		p.Pos = v.Pos.WithNotStmt()
  7502  	}
  7503  	if sym, ok := v.Aux.(*ssa.AuxCall); ok && sym.Fn != nil {
  7504  		p.To.Type = obj.TYPE_MEM
  7505  		p.To.Name = obj.NAME_EXTERN
  7506  		p.To.Sym = sym.Fn
  7507  	} else {
  7508  		// TODO(mdempsky): Can these differences be eliminated?
  7509  		switch Arch.LinkArch.Family {
  7510  		case sys.AMD64, sys.I386, sys.PPC64, sys.RISCV64, sys.S390X, sys.Wasm:
  7511  			p.To.Type = obj.TYPE_REG
  7512  		case sys.ARM, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64:
  7513  			p.To.Type = obj.TYPE_MEM
  7514  		default:
  7515  			base.Fatalf("unknown indirect call family")
  7516  		}
  7517  		p.To.Reg = v.Args[0].Reg()
  7518  	}
  7519  	return p
  7520  }
  7521  
  7522  // TailCall returns a new tail call instruction for the SSA value v.
  7523  // It is like Call, but for a tail call.
  7524  func (s *State) TailCall(v *ssa.Value) *obj.Prog {
  7525  	p := s.Call(v)
  7526  	p.As = obj.ARET
  7527  	return p
  7528  }
  7529  
  7530  // PrepareCall prepares to emit a CALL instruction for v and does call-related bookkeeping.
  7531  // It must be called immediately before emitting the actual CALL instruction,
  7532  // since it emits PCDATA for the stack map at the call (calls are safe points).
  7533  func (s *State) PrepareCall(v *ssa.Value) {
  7534  	idx := s.livenessMap.Get(v)
  7535  	if !idx.StackMapValid() {
  7536  		// See Liveness.hasStackMap.
  7537  		if sym, ok := v.Aux.(*ssa.AuxCall); !ok || !(sym.Fn == ir.Syms.WBZero || sym.Fn == ir.Syms.WBMove) {
  7538  			base.Fatalf("missing stack map index for %v", v.LongString())
  7539  		}
  7540  	}
  7541  
  7542  	call, ok := v.Aux.(*ssa.AuxCall)
  7543  
  7544  	if ok {
  7545  		// Record call graph information for nowritebarrierrec
  7546  		// analysis.
  7547  		if nowritebarrierrecCheck != nil {
  7548  			nowritebarrierrecCheck.recordCall(s.pp.CurFunc, call.Fn, v.Pos)
  7549  		}
  7550  	}
  7551  
  7552  	if s.maxarg < v.AuxInt {
  7553  		s.maxarg = v.AuxInt
  7554  	}
  7555  }
  7556  
  7557  // UseArgs records the fact that an instruction needs a certain amount of
  7558  // callee args space for its use.
  7559  func (s *State) UseArgs(n int64) {
  7560  	if s.maxarg < n {
  7561  		s.maxarg = n
  7562  	}
  7563  }
  7564  
  7565  // fieldIdx finds the index of the field referred to by the ODOT node n.
  7566  func fieldIdx(n *ir.SelectorExpr) int {
  7567  	t := n.X.Type()
  7568  	if !t.IsStruct() {
  7569  		panic("ODOT's LHS is not a struct")
  7570  	}
  7571  
  7572  	for i, f := range t.Fields() {
  7573  		if f.Sym == n.Sel {
  7574  			if f.Offset != n.Offset() {
  7575  				panic("field offset doesn't match")
  7576  			}
  7577  			return i
  7578  		}
  7579  	}
  7580  	panic(fmt.Sprintf("can't find field in expr %v\n", n))
  7581  
  7582  	// TODO: keep the result of this function somewhere in the ODOT Node
  7583  	// so we don't have to recompute it each time we need it.
  7584  }
  7585  
  7586  // ssafn holds frontend information about a function that the backend is processing.
  7587  // It also exports a bunch of compiler services for the ssa backend.
  7588  type ssafn struct {
  7589  	curfn      *ir.Func
  7590  	strings    map[string]*obj.LSym // map from constant string to data symbols
  7591  	stksize    int64                // stack size for current frame
  7592  	stkptrsize int64                // prefix of stack containing pointers
  7593  
  7594  	// alignment for current frame.
  7595  	// NOTE: when stkalign > PtrSize, currently this only ensures the offsets of
  7596  	// objects in the stack frame are aligned. The stack pointer is still aligned
  7597  	// only PtrSize.
  7598  	stkalign int64
  7599  
  7600  	log bool // print ssa debug to the stdout
  7601  }
  7602  
  7603  // StringData returns a symbol which
  7604  // is the data component of a global string constant containing s.
  7605  func (e *ssafn) StringData(s string) *obj.LSym {
  7606  	if aux, ok := e.strings[s]; ok {
  7607  		return aux
  7608  	}
  7609  	if e.strings == nil {
  7610  		e.strings = make(map[string]*obj.LSym)
  7611  	}
  7612  	data := staticdata.StringSym(e.curfn.Pos(), s)
  7613  	e.strings[s] = data
  7614  	return data
  7615  }
  7616  
  7617  // SplitSlot returns a slot representing the data of parent starting at offset.
  7618  func (e *ssafn) SplitSlot(parent *ssa.LocalSlot, suffix string, offset int64, t *types.Type) ssa.LocalSlot {
  7619  	node := parent.N
  7620  
  7621  	if node.Class != ir.PAUTO || node.Addrtaken() {
  7622  		// addressed things and non-autos retain their parents (i.e., cannot truly be split)
  7623  		return ssa.LocalSlot{N: node, Type: t, Off: parent.Off + offset}
  7624  	}
  7625  
  7626  	sym := &types.Sym{Name: node.Sym().Name + suffix, Pkg: types.LocalPkg}
  7627  	n := e.curfn.NewLocal(parent.N.Pos(), sym, t)
  7628  	n.SetUsed(true)
  7629  	n.SetEsc(ir.EscNever)
  7630  	types.CalcSize(t)
  7631  	return ssa.LocalSlot{N: n, Type: t, Off: 0, SplitOf: parent, SplitOffset: offset}
  7632  }
  7633  
  7634  // Logf logs a message from the compiler.
  7635  func (e *ssafn) Logf(msg string, args ...interface{}) {
  7636  	if e.log {
  7637  		fmt.Printf(msg, args...)
  7638  	}
  7639  }
  7640  
  7641  func (e *ssafn) Log() bool {
  7642  	return e.log
  7643  }
  7644  
  7645  // Fatalf reports a compiler error and exits.
  7646  func (e *ssafn) Fatalf(pos src.XPos, msg string, args ...interface{}) {
  7647  	base.Pos = pos
  7648  	nargs := append([]interface{}{ir.FuncName(e.curfn)}, args...)
  7649  	base.Fatalf("'%s': "+msg, nargs...)
  7650  }
  7651  
  7652  // Warnl reports a "warning", which is usually flag-triggered
  7653  // logging output for the benefit of tests.
  7654  func (e *ssafn) Warnl(pos src.XPos, fmt_ string, args ...interface{}) {
  7655  	base.WarnfAt(pos, fmt_, args...)
  7656  }
  7657  
  7658  func (e *ssafn) Debug_checknil() bool {
  7659  	return base.Debug.Nil != 0
  7660  }
  7661  
  7662  func (e *ssafn) UseWriteBarrier() bool {
  7663  	return base.Flag.WB
  7664  }
  7665  
  7666  func (e *ssafn) Syslook(name string) *obj.LSym {
  7667  	switch name {
  7668  	case "goschedguarded":
  7669  		return ir.Syms.Goschedguarded
  7670  	case "writeBarrier":
  7671  		return ir.Syms.WriteBarrier
  7672  	case "wbZero":
  7673  		return ir.Syms.WBZero
  7674  	case "wbMove":
  7675  		return ir.Syms.WBMove
  7676  	case "cgoCheckMemmove":
  7677  		return ir.Syms.CgoCheckMemmove
  7678  	case "cgoCheckPtrWrite":
  7679  		return ir.Syms.CgoCheckPtrWrite
  7680  	}
  7681  	e.Fatalf(src.NoXPos, "unknown Syslook func %v", name)
  7682  	return nil
  7683  }
  7684  
  7685  func (e *ssafn) Func() *ir.Func {
  7686  	return e.curfn
  7687  }
  7688  
  7689  func clobberBase(n ir.Node) ir.Node {
  7690  	if n.Op() == ir.ODOT {
  7691  		n := n.(*ir.SelectorExpr)
  7692  		if n.X.Type().NumFields() == 1 {
  7693  			return clobberBase(n.X)
  7694  		}
  7695  	}
  7696  	if n.Op() == ir.OINDEX {
  7697  		n := n.(*ir.IndexExpr)
  7698  		if n.X.Type().IsArray() && n.X.Type().NumElem() == 1 {
  7699  			return clobberBase(n.X)
  7700  		}
  7701  	}
  7702  	return n
  7703  }
  7704  
  7705  // callTargetLSym returns the correct LSym to call 'callee' using its ABI.
  7706  func callTargetLSym(callee *ir.Name) *obj.LSym {
  7707  	if callee.Func == nil {
  7708  		// TODO(austin): This happens in case of interface method I.M from imported package.
  7709  		// It's ABIInternal, and would be better if callee.Func was never nil and we didn't
  7710  		// need this case.
  7711  		return callee.Linksym()
  7712  	}
  7713  
  7714  	return callee.LinksymABI(callee.Func.ABI)
  7715  }
  7716  
  7717  // deferStructFnField is the field index of _defer.fn.
  7718  const deferStructFnField = 4
  7719  
  7720  var deferType *types.Type
  7721  
  7722  // deferstruct returns a type interchangeable with runtime._defer.
  7723  // Make sure this stays in sync with runtime/runtime2.go:_defer.
  7724  func deferstruct() *types.Type {
  7725  	if deferType != nil {
  7726  		return deferType
  7727  	}
  7728  
  7729  	makefield := func(name string, t *types.Type) *types.Field {
  7730  		sym := (*types.Pkg)(nil).Lookup(name)
  7731  		return types.NewField(src.NoXPos, sym, t)
  7732  	}
  7733  
  7734  	fields := []*types.Field{
  7735  		makefield("heap", types.Types[types.TBOOL]),
  7736  		makefield("rangefunc", types.Types[types.TBOOL]),
  7737  		makefield("sp", types.Types[types.TUINTPTR]),
  7738  		makefield("pc", types.Types[types.TUINTPTR]),
  7739  		// Note: the types here don't really matter. Defer structures
  7740  		// are always scanned explicitly during stack copying and GC,
  7741  		// so we make them uintptr type even though they are real pointers.
  7742  		makefield("fn", types.Types[types.TUINTPTR]),
  7743  		makefield("link", types.Types[types.TUINTPTR]),
  7744  		makefield("head", types.Types[types.TUINTPTR]),
  7745  	}
  7746  	if name := fields[deferStructFnField].Sym.Name; name != "fn" {
  7747  		base.Fatalf("deferStructFnField is %q, not fn", name)
  7748  	}
  7749  
  7750  	n := ir.NewDeclNameAt(src.NoXPos, ir.OTYPE, ir.Pkgs.Runtime.Lookup("_defer"))
  7751  	typ := types.NewNamed(n)
  7752  	n.SetType(typ)
  7753  	n.SetTypecheck(1)
  7754  
  7755  	// build struct holding the above fields
  7756  	typ.SetUnderlying(types.NewStruct(fields))
  7757  	types.CalcStructSize(typ)
  7758  
  7759  	deferType = typ
  7760  	return typ
  7761  }
  7762  
  7763  // SpillSlotAddr uses LocalSlot information to initialize an obj.Addr
  7764  // The resulting addr is used in a non-standard context -- in the prologue
  7765  // of a function, before the frame has been constructed, so the standard
  7766  // addressing for the parameters will be wrong.
  7767  func SpillSlotAddr(spill ssa.Spill, baseReg int16, extraOffset int64) obj.Addr {
  7768  	return obj.Addr{
  7769  		Name:   obj.NAME_NONE,
  7770  		Type:   obj.TYPE_MEM,
  7771  		Reg:    baseReg,
  7772  		Offset: spill.Offset + extraOffset,
  7773  	}
  7774  }
  7775  
  7776  var (
  7777  	BoundsCheckFunc [ssa.BoundsKindCount]*obj.LSym
  7778  	ExtendCheckFunc [ssa.BoundsKindCount]*obj.LSym
  7779  )
  7780