cmd/compile: make ssa compilation unconditional

Rip out the code that allows SSA to be used conditionally.

No longer exists:
 ssa=0 flag
 GOSSAHASH
 GOSSAPKG
 SSATEST

GOSSAFUNC now only controls the printing of the IR/html.

Still need to rip out all of the old backend.  It should no longer be
callable after this CL.

Update #16357

Change-Id: Ib30cc18fba6ca52232c41689ba610b0a94aa74f5
Reviewed-on: https://go-review.googlesource.com/29155
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

src/cmd/compile/internal/amd64/ssa.go

@@ -684,7 +684,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.To.Offset = off
 	case ssa.OpAMD64MOVOconst:
 		if v.AuxInt != 0 {
-			v.Unimplementedf("MOVOconst can only do constant=0")
+			v.Fatalf("MOVOconst can only do constant=0")
 		}
 		r := gc.SSARegNum(v)
 		opregreg(x86.AXORPS, r, r)
@@ -705,7 +705,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		}
 	case ssa.OpLoadReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("load flags not implemented: %v", v.LongString())
+			v.Fatalf("load flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(loadByType(v.Type))
@@ -725,7 +725,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 
 	case ssa.OpStoreReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("store flags not implemented: %v", v.LongString())
+			v.Fatalf("store flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(storeByType(v.Type))
@@ -1031,7 +1031,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.To.Reg = gc.SSARegNum(v.Args[0])
 		gc.AddAux(&p.To, v)
 	default:
-		v.Unimplementedf("genValue not implemented: %s", v.LongString())
+		v.Fatalf("genValue not implemented: %s", v.LongString())
 	}
 }
 
@@ -1145,6 +1145,6 @@ func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
 		}
 
 	default:
-		b.Unimplementedf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
+		b.Fatalf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
 	}
 }

src/cmd/compile/internal/arm/ssa.go

@@ -201,7 +201,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		// nothing to do
 	case ssa.OpLoadReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("load flags not implemented: %v", v.LongString())
+			v.Fatalf("load flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(loadByType(v.Type))
@@ -222,7 +222,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		gc.CheckLoweredPhi(v)
 	case ssa.OpStoreReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("store flags not implemented: %v", v.LongString())
+			v.Fatalf("store flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(storeByType(v.Type))
@@ -958,7 +958,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 	case ssa.OpARMInvertFlags:
 		v.Fatalf("InvertFlags should never make it to codegen %v", v.LongString())
 	default:
-		v.Unimplementedf("genValue not implemented: %s", v.LongString())
+		v.Fatalf("genValue not implemented: %s", v.LongString())
 	}
 }
 
@@ -1056,6 +1056,6 @@ func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
 		}
 
 	default:
-		b.Unimplementedf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
+		b.Fatalf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
 	}
 }

src/cmd/compile/internal/arm64/ssa.go

@@ -206,7 +206,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		// nothing to do
 	case ssa.OpLoadReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("load flags not implemented: %v", v.LongString())
+			v.Fatalf("load flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(loadByType(v.Type))
@@ -227,7 +227,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		gc.CheckLoweredPhi(v)
 	case ssa.OpStoreReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("store flags not implemented: %v", v.LongString())
+			v.Fatalf("store flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(storeByType(v.Type))
@@ -884,7 +884,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 	case ssa.OpARM64InvertFlags:
 		v.Fatalf("InvertFlags should never make it to codegen %v", v.LongString())
 	default:
-		v.Unimplementedf("genValue not implemented: %s", v.LongString())
+		v.Fatalf("genValue not implemented: %s", v.LongString())
 	}
 }
 
@@ -982,6 +982,6 @@ func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
 		}
 
 	default:
-		b.Unimplementedf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
+		b.Fatalf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
 	}
 }

src/cmd/compile/internal/gc/main.go

@@ -208,7 +208,6 @@ func Main() {
 	flag.StringVar(&cpuprofile, "cpuprofile", "", "write cpu profile to `file`")
 	flag.StringVar(&memprofile, "memprofile", "", "write memory profile to `file`")
 	flag.Int64Var(&memprofilerate, "memprofilerate", 0, "set runtime.MemProfileRate to `rate`")
-	flag.BoolVar(&ssaEnabled, "ssa", true, "use SSA backend to generate code")
 	flag.StringVar(&benchfile, "bench", "", "append benchmark times to `file`")
 	obj.Flagparse(usage)
 

src/cmd/compile/internal/gc/pgen.go

@@ -5,7 +5,6 @@
 package gc
 
 import (
-	"cmd/compile/internal/ssa"
 	"cmd/internal/obj"
 	"cmd/internal/sys"
 	"fmt"
@@ -400,9 +399,9 @@ func compile(fn *Node) {
 	}
 
 	// Build an SSA backend function.
-	var ssafn *ssa.Func
-	if shouldssa(Curfn) {
-		ssafn = buildssa(Curfn)
+	ssafn := buildssa(Curfn)
+	if nerrors != 0 {
+		return
 	}
 
 	continpc = nil
@@ -478,12 +477,8 @@ func compile(fn *Node) {
 		}
 	}
 
-	if ssafn != nil {
 	genssa(ssafn, ptxt, gcargs, gclocals)
 	ssafn.Free()
-	} else {
-		genlegacy(ptxt, gcargs, gclocals)
-	}
 }
 
 type symByName []*Sym
@@ -491,70 +486,3 @@ type symByName []*Sym
 func (a symByName) Len() int           { return len(a) }
 func (a symByName) Less(i, j int) bool { return a[i].Name < a[j].Name }
 func (a symByName) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-
-// genlegacy compiles Curfn using the legacy non-SSA code generator.
-func genlegacy(ptxt *obj.Prog, gcargs, gclocals *Sym) {
-	Genlist(Curfn.Func.Enter)
-	Genlist(Curfn.Nbody)
-	gclean()
-	checklabels()
-	if nerrors != 0 {
-		return
-	}
-	if Curfn.Func.Endlineno != 0 {
-		lineno = Curfn.Func.Endlineno
-	}
-
-	if Curfn.Type.Results().NumFields() != 0 {
-		Ginscall(throwreturn, 0)
-	}
-
-	ginit()
-
-	// TODO: Determine when the final cgen_ret can be omitted. Perhaps always?
-	cgen_ret(nil)
-
-	if hasdefer {
-		// deferreturn pretends to have one uintptr argument.
-		// Reserve space for it so stack scanner is happy.
-		if Maxarg < int64(Widthptr) {
-			Maxarg = int64(Widthptr)
-		}
-	}
-
-	gclean()
-	if nerrors != 0 {
-		return
-	}
-
-	Pc.As = obj.ARET // overwrite AEND
-	Pc.Lineno = lineno
-
-	fixjmp(ptxt)
-	if Debug['N'] == 0 || Debug['R'] != 0 || Debug['P'] != 0 {
-		regopt(ptxt)
-		nilopt(ptxt)
-	}
-
-	Thearch.Expandchecks(ptxt)
-
-	allocauto(ptxt)
-
-	setlineno(Curfn)
-	if Stksize+Maxarg > 1<<31 {
-		Yyerror("stack frame too large (>2GB)")
-		return
-	}
-
-	// Emit garbage collection symbols.
-	liveness(Curfn, ptxt, gcargs, gclocals)
-
-	Thearch.Defframe(ptxt)
-
-	if Debug['f'] != 0 {
-		frame(0)
-	}
-
-	// Remove leftover instrumentation from the instruction stream.
-	removevardef(ptxt)
-}

src/cmd/compile/internal/mips64/ssa.go

@@ -201,7 +201,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		// nothing to do
 	case ssa.OpLoadReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("load flags not implemented: %v", v.LongString())
+			v.Fatalf("load flags not implemented: %v", v.LongString())
 			return
 		}
 		r := gc.SSARegNum(v)
@@ -232,7 +232,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		gc.CheckLoweredPhi(v)
 	case ssa.OpStoreReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("store flags not implemented: %v", v.LongString())
+			v.Fatalf("store flags not implemented: %v", v.LongString())
 			return
 		}
 		r := gc.SSARegNum(v.Args[0])
@@ -744,7 +744,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		// Closure pointer is R22 (mips.REGCTXT).
 		gc.CheckLoweredGetClosurePtr(v)
 	default:
-		v.Unimplementedf("genValue not implemented: %s", v.LongString())
+		v.Fatalf("genValue not implemented: %s", v.LongString())
 	}
 }
 
@@ -823,6 +823,6 @@ func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
 			p.From.Reg = gc.SSARegNum(b.Control)
 		}
 	default:
-		b.Unimplementedf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
+		b.Fatalf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
 	}
 }

src/cmd/compile/internal/ppc64/ssa.go

@@ -925,7 +925,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		v.Fatalf("Flag* ops should never make it to codegen %v", v.LongString())
 
 	default:
-		v.Unimplementedf("genValue not implemented: %s", v.LongString())
+		v.Fatalf("genValue not implemented: %s", v.LongString())
 	}
 }
 
@@ -1045,6 +1045,6 @@ func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
 		//}
 
 	default:
-		b.Unimplementedf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
+		b.Fatalf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
 	}
 }

src/cmd/compile/internal/s390x/ssa.go

@@ -464,7 +464,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		}
 	case ssa.OpLoadReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("load flags not implemented: %v", v.LongString())
+			v.Fatalf("load flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(loadByType(v.Type))
@@ -483,7 +483,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.To.Reg = gc.SSARegNum(v)
 	case ssa.OpStoreReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("store flags not implemented: %v", v.LongString())
+			v.Fatalf("store flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(storeByType(v.Type))
@@ -800,7 +800,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 			clear.To.Reg = gc.SSARegNum(v.Args[0])
 		}
 	default:
-		v.Unimplementedf("genValue not implemented: %s", v.LongString())
+		v.Fatalf("genValue not implemented: %s", v.LongString())
 	}
 }
 
@@ -880,6 +880,6 @@ func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
 			s.Branches = append(s.Branches, gc.Branch{P: q, B: b.Succs[1].Block()})
 		}
 	default:
-		b.Unimplementedf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
+		b.Fatalf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
 	}
 }

src/cmd/compile/internal/ssa/block.go

@@ -192,7 +192,6 @@ func (b *Block) swapSuccessors() {
 func (b *Block) Logf(msg string, args ...interface{})   { b.Func.Logf(msg, args...) }
 func (b *Block) Log() bool                              { return b.Func.Log() }
 func (b *Block) Fatalf(msg string, args ...interface{}) { b.Func.Fatalf(msg, args...) }
-func (b *Block) Unimplementedf(msg string, args ...interface{}) { b.Func.Unimplementedf(msg, args...) }
 
 type BranchPrediction int8
 

src/cmd/compile/internal/ssa/config.go

@@ -85,10 +85,6 @@ type Logger interface {
 	// Fatal reports a compiler error and exits.
 	Fatalf(line int32, msg string, args ...interface{})
 
-	// Unimplemented reports that the function cannot be compiled.
-	// It will be removed once SSA work is complete.
-	Unimplementedf(line int32, msg string, args ...interface{})
-
 	// Warnl writes compiler messages in the form expected by "errorcheck" tests
 	Warnl(line int32, fmt_ string, args ...interface{})
 
@@ -218,7 +214,7 @@ func NewConfig(arch string, fe Frontend, ctxt *obj.Link, optimize bool) *Config
 		c.hasGReg = true
 		c.noDuffDevice = true
 	default:
-		fe.Unimplementedf(0, "arch %s not implemented", arch)
+		fe.Fatalf(0, "arch %s not implemented", arch)
 	}
 	c.ctxt = ctxt
 	c.optimize = optimize
@@ -294,9 +290,6 @@ func (c *Config) NewFunc() *Func {
 func (c *Config) Logf(msg string, args ...interface{})               { c.fe.Logf(msg, args...) }
 func (c *Config) Log() bool                                          { return c.fe.Log() }
 func (c *Config) Fatalf(line int32, msg string, args ...interface{}) { c.fe.Fatalf(line, msg, args...) }
-func (c *Config) Unimplementedf(line int32, msg string, args ...interface{}) {
-	c.fe.Unimplementedf(line, msg, args...)
-}
 func (c *Config) Warnl(line int32, msg string, args ...interface{})  { c.fe.Warnl(line, msg, args...) }
 func (c *Config) Debug_checknil() bool                               { return c.fe.Debug_checknil() }
 

src/cmd/compile/internal/ssa/decompose.go

@@ -97,7 +97,7 @@ func decomposeBuiltIn(f *Func) {
 		case t.IsFloat():
 			// floats are never decomposed, even ones bigger than IntSize
 		case t.Size() > f.Config.IntSize:
-			f.Unimplementedf("undecomposed named type %s %s", name, t)
+			f.Fatalf("undecomposed named type %s %s", name, t)
 		default:
 			newNames = append(newNames, name)
 		}
@@ -124,7 +124,7 @@ func decomposeBuiltInPhi(v *Value) {
 	case v.Type.IsFloat():
 		// floats are never decomposed, even ones bigger than IntSize
 	case v.Type.Size() > v.Block.Func.Config.IntSize:
-		v.Unimplementedf("undecomposed type %s", v.Type)
+		v.Fatalf("undecomposed type %s", v.Type)
 	}
 }
 

src/cmd/compile/internal/ssa/export_test.go

@@ -66,9 +66,6 @@ func (d DummyFrontend) Logf(msg string, args ...interface{}) { d.t.Logf(msg, arg
 func (d DummyFrontend) Log() bool                            { return true }
 
 func (d DummyFrontend) Fatalf(line int32, msg string, args ...interface{}) { d.t.Fatalf(msg, args...) }
-func (d DummyFrontend) Unimplementedf(line int32, msg string, args ...interface{}) {
-	d.t.Fatalf(msg, args...)
-}
 func (d DummyFrontend) Warnl(line int32, msg string, args ...interface{})  { d.t.Logf(msg, args...) }
 func (d DummyFrontend) Debug_checknil() bool                               { return false }
 

src/cmd/compile/internal/ssa/func.go

@@ -407,9 +407,6 @@ func (f *Func) ConstEmptyString(line int32, t Type) *Value {
 func (f *Func) Logf(msg string, args ...interface{})   { f.Config.Logf(msg, args...) }
 func (f *Func) Log() bool                              { return f.Config.Log() }
 func (f *Func) Fatalf(msg string, args ...interface{}) { f.Config.Fatalf(f.Entry.Line, msg, args...) }
-func (f *Func) Unimplementedf(msg string, args ...interface{}) {
-	f.Config.Unimplementedf(f.Entry.Line, msg, args...)
-}
 
 func (f *Func) Free() {
 	// Clear values.

src/cmd/compile/internal/ssa/lower.go

@@ -33,7 +33,7 @@ func checkLower(f *Func) {
 			for _, a := range v.Args {
 				s += " " + a.Type.SimpleString()
 			}
-			f.Unimplementedf("%s", s)
+			f.Fatalf("%s", s)
 		}
 	}
 }

src/cmd/compile/internal/ssa/regalloc.go

@@ -373,7 +373,7 @@ func (s *regAllocState) allocReg(mask regMask, v *Value) register {
 		}
 	}
 	if maxuse == -1 {
-		s.f.Unimplementedf("couldn't find register to spill")
+		s.f.Fatalf("couldn't find register to spill")
 	}
 	s.freeReg(r)
 	return r
@@ -505,7 +505,7 @@ func (s *regAllocState) init(f *Func) {
 		case "s390x":
 			// nothing to do, R10 & R11 already reserved
 		default:
-			s.f.Config.fe.Unimplementedf(0, "arch %s not implemented", s.f.Config.arch)
+			s.f.Config.fe.Fatalf(0, "arch %s not implemented", s.f.Config.arch)
 		}
 	}
 	if s.f.Config.nacl {

src/cmd/compile/internal/ssa/value.go

@@ -228,9 +228,6 @@ func (v *Value) Log() bool                            { return v.Block.Log() }
 func (v *Value) Fatalf(msg string, args ...interface{}) {
 	v.Block.Func.Config.Fatalf(v.Line, msg, args...)
 }
-func (v *Value) Unimplementedf(msg string, args ...interface{}) {
-	v.Block.Func.Config.Unimplementedf(v.Line, msg, args...)
-}
 
 // isGenericIntConst returns whether v is a generic integer constant.
 func (v *Value) isGenericIntConst() bool {

src/cmd/compile/internal/x86/ssa.go

@@ -630,7 +630,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		}
 	case ssa.OpLoadReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("load flags not implemented: %v", v.LongString())
+			v.Fatalf("load flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(loadByType(v.Type))
@@ -650,7 +650,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 
 	case ssa.OpStoreReg:
 		if v.Type.IsFlags() {
-			v.Unimplementedf("store flags not implemented: %v", v.LongString())
+			v.Fatalf("store flags not implemented: %v", v.LongString())
 			return
 		}
 		p := gc.Prog(storeByType(v.Type))
@@ -886,7 +886,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 	case ssa.Op386FCHS:
 		v.Fatalf("FCHS in non-387 mode")
 	default:
-		v.Unimplementedf("genValue not implemented: %s", v.LongString())
+		v.Fatalf("genValue not implemented: %s", v.LongString())
 	}
 }
 
@@ -1005,6 +1005,6 @@ func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
 		}
 
 	default:
-		b.Unimplementedf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
+		b.Fatalf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
 	}
 }