[dev.ssa] cmd/compile/ssa: separate logging, work in progress, and fatal errors

The SSA implementation logs for three purposes:

	* debug logging
	* fatal errors
	* unimplemented features

Separating these three uses lets us attempt an SSA
implementation for all functions, not just
_ssa functions. This turns the entire standard
library into a compilation test, and makes it
easy to figure out things like
"how much coverage does SSA have now" and
"what should we do next to get more coverage?".

Functions called _ssa are still special.
They log profusely by default and
the output of the SSA implementation
is used. For all other functions,
logging is off, and the implementation
is built and discarded, due to lack of
support for the runtime.

While we're here, fix a few minor bugs and
add some extra Unimplementeds to allow
all.bash to pass.

As of now, SSA handles 20.79% of the functions
in the standard library (689 of 3314).

The top missing features are:

 10.03%  2597 SSA unimplemented: zero for type error not implemented
  7.79%  2016 SSA unimplemented: addr: bad op DOTPTR
  7.33%  1898 SSA unimplemented: unhandled expr EQ
  6.10%  1579 SSA unimplemented: unhandled expr OROR
  4.91%  1271 SSA unimplemented: unhandled expr NE
  4.49%  1163 SSA unimplemented: unhandled expr LROT
  4.00%  1036 SSA unimplemented: unhandled expr LEN
  3.56%   923 SSA unimplemented: unhandled stmt CALLFUNC
  2.37%   615 SSA unimplemented: zero for type []byte not implemented
  1.90%   492 SSA unimplemented: unhandled stmt CALLMETH
  1.74%   450 SSA unimplemented: unhandled expr CALLINTER
  1.74%   450 SSA unimplemented: unhandled expr DOT
  1.71%   444 SSA unimplemented: unhandled expr ANDAND
  1.65%   426 SSA unimplemented: unhandled expr CLOSUREVAR
  1.54%   400 SSA unimplemented: unhandled expr CALLMETH
  1.51%   390 SSA unimplemented: unhandled stmt SWITCH
  1.47%   380 SSA unimplemented: unhandled expr CONV
  1.33%   345 SSA unimplemented: addr: bad op *
  1.30%   336 SSA unimplemented: unhandled OLITERAL 6

Change-Id: I4ca07951e276714dc13c31de28640aead17a1be7
Reviewed-on: https://go-review.googlesource.com/11160
Reviewed-by: Keith Randall <khr@golang.org>

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

@@ -355,6 +355,7 @@ func compile(fn *Node) {
 	var gcargs *Sym
 	var gclocals *Sym
 	var ssafn *ssa.Func
+	var usessa bool
 	if fn.Nbody == nil {
 		if pure_go != 0 || strings.HasPrefix(fn.Func.Nname.Sym.Name, "init.") {
 			Yyerror("missing function body for %q", fn.Func.Nname.Sym.Name)
@@ -406,13 +407,9 @@ func compile(fn *Node) {
 		goto ret
 	}
 
-	// Build an SSA backend function
+	// Build an SSA backend function.
-	{
+	// TODO: get rid of usessa.
-		name := Curfn.Func.Nname.Sym.Name
+	ssafn, usessa = buildssa(Curfn)
-		if len(name) > 4 && name[len(name)-4:] == "_ssa" {
-			ssafn = buildssa(Curfn)
-		}
-	}
 
 	continpc = nil
 	breakpc = nil
@@ -475,7 +472,7 @@ func compile(fn *Node) {
 		}
 	}
 
-	if ssafn != nil {
+	if ssafn != nil && usessa {
 		genssa(ssafn, ptxt, gcargs, gclocals)
 		return
 	}

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

@@ -5,26 +5,48 @@
 package gc
 
 import (
-	"log"
+	"fmt"
 
 	"cmd/compile/internal/ssa"
 	"cmd/internal/obj"
 	"cmd/internal/obj/x86" // TODO: remove
 )
 
-func buildssa(fn *Node) *ssa.Func {
+// buildssa builds an SSA function
-	dumplist("buildssa-enter", fn.Func.Enter)
+// and reports whether it should be used.
-	dumplist("buildssa-body", fn.Nbody)
+// Once the SSA implementation is complete,
+// it will never return nil, and the bool can be removed.
+func buildssa(fn *Node) (ssafn *ssa.Func, usessa bool) {
+	name := fn.Func.Nname.Sym.Name
+	usessa = len(name) > 4 && name[len(name)-4:] == "_ssa"
+
+	if usessa {
+		dumplist("buildssa-enter", fn.Func.Enter)
+		dumplist("buildssa-body", fn.Nbody)
+	}
 
 	var s state
-
 	s.pushLine(fn.Lineno)
 	defer s.popLine()
 
 	// TODO(khr): build config just once at the start of the compiler binary
-	s.config = ssa.NewConfig(Thearch.Thestring, ssaExport{})
+
+	var e ssaExport
+	e.log = usessa
+	s.config = ssa.NewConfig(Thearch.Thestring, &e)
 	s.f = s.config.NewFunc()
-	s.f.Name = fn.Func.Nname.Sym.Name
+	s.f.Name = name
+
+	// If SSA support for the function is incomplete,
+	// assume that any panics are due to violated
+	// invariants. Swallow them silently.
+	defer func() {
+		if err := recover(); err != nil {
+			if !e.unimplemented {
+				panic(err)
+			}
+		}
+	}()
 
 	// We construct SSA using an algorithm similar to
 	// Brau, Buchwald, Hack, Leißa, Mallon, and Zwinkau
@@ -67,7 +89,15 @@ func buildssa(fn *Node) *ssa.Func {
 	// Main call to ssa package to compile function
 	ssa.Compile(s.f)
 
-	return s.f
+	// Calculate stats about what percentage of functions SSA handles.
+	if false {
+		fmt.Printf("SSA implemented: %t\n", !e.unimplemented)
+	}
+
+	if e.unimplemented {
+		return nil, false
+	}
+	return s.f, usessa // TODO: return s.f, true once runtime support is in (gc maps, write barriers, etc.)
 }
 
 type state struct {
@@ -105,10 +135,13 @@ type state struct {
 	line []int32
 }
 
+func (s *state) Fatal(msg string, args ...interface{})         { s.config.Fatal(msg, args...) }
+func (s *state) Unimplemented(msg string, args ...interface{}) { s.config.Unimplemented(msg, args...) }
+
 // startBlock sets the current block we're generating code in to b.
 func (s *state) startBlock(b *ssa.Block) {
 	if s.curBlock != nil {
-		log.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
+		s.Fatal("starting block %v when block %v has not ended", b, s.curBlock)
 	}
 	s.curBlock = b
 	s.vars = map[string]*ssa.Value{}
@@ -230,7 +263,7 @@ func (s *state) stmt(n *Node) {
 			return
 		}
 		if compiling_runtime != 0 {
-			log.Fatalf("%v escapes to heap, not allowed in runtime.", n)
+			Fatal("%v escapes to heap, not allowed in runtime.", n)
 		}
 
 		// TODO: the old pass hides the details of PHEAP
@@ -260,6 +293,9 @@ func (s *state) stmt(n *Node) {
 			// next we work on the label's target block
 			s.startBlock(t)
 		}
+		if n.Op == OGOTO && s.curBlock == nil {
+			s.Unimplemented("goto at start of function; see test/goto.go")
+		}
 
 	case OAS, OASWB:
 		s.assign(n.Op, n.Left, n.Right)
@@ -317,6 +353,9 @@ func (s *state) stmt(n *Node) {
 
 		// generate code to test condition
 		// TODO(khr): Left == nil exception
+		if n.Left == nil {
+			s.Unimplemented("cond n.Left == nil: %v", n)
+		}
 		s.startBlock(bCond)
 		cond := s.expr(n.Left)
 		b = s.endBlock()
@@ -342,7 +381,7 @@ func (s *state) stmt(n *Node) {
 		// TODO(khr): ??? anything to do here?  Only for addrtaken variables?
 		// Maybe just link it in the store chain?
 	default:
-		log.Fatalf("unhandled stmt %s", opnames[n.Op])
+		s.Unimplemented("unhandled stmt %s", opnames[n.Op])
 	}
 }
 
@@ -370,7 +409,7 @@ func (s *state) expr(n *Node) *ssa.Value {
 		case CTSTR:
 			return s.entryNewValue0A(ssa.OpConst, n.Type, n.Val().U)
 		default:
-			log.Fatalf("unhandled OLITERAL %v", n.Val().Ctype())
+			s.Unimplemented("unhandled OLITERAL %v", n.Val().Ctype())
 			return nil
 		}
 	case OCONVNOP:
@@ -474,7 +513,7 @@ func (s *state) expr(n *Node) *ssa.Value {
 		a := s.entryNewValue1I(ssa.OpOffPtr, Ptrto(fp.Type), fp.Width, s.sp)
 		return s.newValue2(ssa.OpLoad, fp.Type, a, call)
 	default:
-		log.Fatalf("unhandled expr %s", opnames[n.Op])
+		s.Unimplemented("unhandled expr %s", opnames[n.Op])
 		return nil
 	}
 }
@@ -494,7 +533,7 @@ func (s *state) assign(op uint8, left *Node, right *Node) {
 		case t.IsBoolean():
 			val = s.entryNewValue0A(ssa.OpConst, left.Type, false) // TODO: store bools as 0/1 in AuxInt?
 		default:
-			log.Fatalf("zero for type %v not implemented", t)
+			s.Unimplemented("zero for type %v not implemented", t)
 		}
 	} else {
 		val = s.expr(right)
@@ -524,7 +563,7 @@ func (s *state) addr(n *Node) *ssa.Value {
 			return s.expr(n.Name.Heapaddr)
 		default:
 			// TODO: address of locals
-			log.Fatalf("variable address of %v not implemented", n)
+			s.Unimplemented("variable address of %v not implemented", n)
 			return nil
 		}
 	case OINDREG:
@@ -547,7 +586,7 @@ func (s *state) addr(n *Node) *ssa.Value {
 			return s.newValue2(ssa.OpPtrIndex, Ptrto(n.Left.Type.Type), p, i)
 		}
 	default:
-		log.Fatalf("addr: bad op %v", Oconv(int(n.Op), 0))
+		s.Unimplemented("addr: bad op %v", Oconv(int(n.Op), 0))
 		return nil
 	}
 }
@@ -556,7 +595,7 @@ func (s *state) addr(n *Node) *ssa.Value {
 // n must be an ONAME.
 func canSSA(n *Node) bool {
 	if n.Op != ONAME {
-		log.Fatalf("canSSA passed a non-ONAME %s %v", Oconv(int(n.Op), 0), n)
+		Fatal("canSSA passed a non-ONAME %s %v", Oconv(int(n.Op), 0), n)
 	}
 	if n.Addrtaken {
 		return false
@@ -610,7 +649,7 @@ func (s *state) boundsCheck(idx, len *ssa.Value) {
 // variable returns the value of a variable at the current location.
 func (s *state) variable(name string, t ssa.Type) *ssa.Value {
 	if s.curBlock == nil {
-		log.Fatalf("nil curblock!")
+		s.Fatal("nil curblock!")
 	}
 	v := s.vars[name]
 	if v == nil {
@@ -662,6 +701,10 @@ func (s *state) lookupVarIncoming(b *ssa.Block, t ssa.Type, name string) *ssa.Va
 	for _, p := range b.Preds {
 		vals = append(vals, s.lookupVarOutgoing(p, t, name))
 	}
+	if len(vals) == 0 {
+		s.Unimplemented("TODO: Handle fixedbugs/bug076.go")
+		return nil
+	}
 	v0 := vals[0]
 	for i := 1; i < len(vals); i++ {
 		if vals[i] != v0 {
@@ -822,11 +865,14 @@ func genValue(v *ssa.Value) {
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = regnum(v)
 	case ssa.OpAMD64MULQconst:
+		v.Unimplemented("IMULQ doasm")
+		return
 		// TODO: this isn't right.  doasm fails on it.  I don't think obj
 		// has ever been taught to compile imul $c, r1, r2.
 		p := Prog(x86.AIMULQ)
 		p.From.Type = obj.TYPE_CONST
 		p.From.Offset = v.AuxInt
+		p.From3 = new(obj.Addr)
 		p.From3.Type = obj.TYPE_REG
 		p.From3.Reg = regnum(v.Args[0])
 		p.To.Type = obj.TYPE_REG
@@ -854,7 +900,7 @@ func genValue(v *ssa.Value) {
 		r := regnum(v)
 		if x != r {
 			if r == x86.REG_CX {
-				log.Fatalf("can't implement %s, target and shift both in CX", v.LongString())
+				v.Fatal("can't implement %s, target and shift both in CX", v.LongString())
 			}
 			p := Prog(x86.AMOVQ)
 			p.From.Type = obj.TYPE_REG
@@ -1003,12 +1049,12 @@ func genValue(v *ssa.Value) {
 		loc := f.RegAlloc[v.ID]
 		for _, a := range v.Args {
 			if f.RegAlloc[a.ID] != loc { // TODO: .Equal() instead?
-				log.Fatalf("phi arg at different location than phi %v %v %v %v", v, loc, a, f.RegAlloc[a.ID])
+				v.Fatal("phi arg at different location than phi %v %v %v %v", v, loc, a, f.RegAlloc[a.ID])
 			}
 		}
 	case ssa.OpConst:
 		if v.Block.Func.RegAlloc[v.ID] != nil {
-			log.Fatalf("const value %v shouldn't have a location", v)
+			v.Fatal("const value %v shouldn't have a location", v)
 		}
 	case ssa.OpArg:
 		// memory arg needs no code
@@ -1033,7 +1079,7 @@ func genValue(v *ssa.Value) {
 	case ssa.OpFP, ssa.OpSP:
 		// nothing to do
 	default:
-		log.Fatalf("value %s not implemented", v.LongString())
+		v.Unimplemented("value %s not implemented", v.LongString())
 	}
 }
 
@@ -1141,7 +1187,7 @@ func genBlock(b, next *ssa.Block, branches []branch) []branch {
 		}
 
 	default:
-		log.Fatalf("branch %s not implemented", b.LongString())
+		b.Unimplemented("branch %s not implemented", b.LongString())
 	}
 	return branches
 }
@@ -1183,10 +1229,40 @@ func localOffset(v *ssa.Value) int64 {
 }
 
 // ssaExport exports a bunch of compiler services for the ssa backend.
-type ssaExport struct{}
+type ssaExport struct {
+	log           bool
+	unimplemented bool
+}
 
 // StringSym returns a symbol (a *Sym wrapped in an interface) which
 // is a global string constant containing s.
-func (serv ssaExport) StringSym(s string) interface{} {
+func (*ssaExport) StringSym(s string) interface{} {
 	return stringsym(s)
 }
+
+// Log logs a message from the compiler.
+func (e *ssaExport) Log(msg string, args ...interface{}) {
+	// If e was marked as unimplemented, anything could happen. Ignore.
+	if e.log && !e.unimplemented {
+		fmt.Printf(msg, args...)
+	}
+}
+
+// Fatal reports a compiler error and exits.
+func (e *ssaExport) Fatal(msg string, args ...interface{}) {
+	// If e was marked as unimplemented, anything could happen. Ignore.
+	if !e.unimplemented {
+		Fatal(msg, args...)
+	}
+}
+
+// Unimplemented reports that the function cannot be compiled.
+// It will be removed once SSA work is complete.
+func (e *ssaExport) Unimplemented(msg string, args ...interface{}) {
+	const alwaysLog = false // enable to calculate top unimplemented features
+	if !e.unimplemented && (e.log || alwaysLog) {
+		// first implementation failure, print explanation
+		fmt.Printf("SSA unimplemented: "+msg+"\n", args...)
+	}
+	e.unimplemented = true
+}

src/cmd/compile/internal/ssa/TODO

@@ -42,7 +42,6 @@ Common-Subexpression Elimination
  - Can we move control values out of their basic block?
 
 Other
- - Use gc.Fatal for errors.  Add a callback to Frontend?
  - Write barriers
  - For testing, do something more sophisticated than
    checkOpcodeCounts.  Michael Matloob suggests using a similar

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

@@ -69,3 +69,7 @@ func (b *Block) LongString() string {
 	}
 	return s
 }
+
+func (b *Block) Log(msg string, args ...interface{})           { b.Func.Log(msg, args...) }
+func (b *Block) Fatal(msg string, args ...interface{})         { b.Func.Fatal(msg, args...) }
+func (b *Block) Unimplemented(msg string, args ...interface{}) { b.Func.Unimplemented(msg, args...) }

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

@@ -4,8 +4,6 @@
 
 package ssa
 
-import "log"
-
 // checkFunc checks invariants of f.
 func checkFunc(f *Func) {
 	blockMark := make([]bool, f.NumBlocks())
@@ -13,17 +11,17 @@ func checkFunc(f *Func) {
 
 	for _, b := range f.Blocks {
 		if blockMark[b.ID] {
-			log.Panicf("block %s appears twice in %s!", b, f.Name)
+			f.Fatal("block %s appears twice in %s!", b, f.Name)
 		}
 		blockMark[b.ID] = true
 		if b.Func != f {
-			log.Panicf("%s.Func=%s, want %s", b, b.Func.Name, f.Name)
+			f.Fatal("%s.Func=%s, want %s", b, b.Func.Name, f.Name)
 		}
 
 		for i, c := range b.Succs {
 			for j, d := range b.Succs {
 				if i != j && c == d {
-					log.Panicf("%s.Succs has duplicate block %s", b, c)
+					f.Fatal("%s.Succs has duplicate block %s", b, c)
 				}
 			}
 		}
@@ -46,64 +44,64 @@ func checkFunc(f *Func) {
 				}
 			}
 			if !found {
-				log.Panicf("block %s is not a succ of its pred block %s", b, p)
+				f.Fatal("block %s is not a succ of its pred block %s", b, p)
 			}
 		}
 
 		switch b.Kind {
 		case BlockExit:
 			if len(b.Succs) != 0 {
-				log.Panicf("exit block %s has successors", b)
+				f.Fatal("exit block %s has successors", b)
 			}
 			if b.Control == nil {
-				log.Panicf("exit block %s has no control value", b)
+				f.Fatal("exit block %s has no control value", b)
 			}
 			if !b.Control.Type.IsMemory() {
-				log.Panicf("exit block %s has non-memory control value %s", b, b.Control.LongString())
+				f.Fatal("exit block %s has non-memory control value %s", b, b.Control.LongString())
 			}
 		case BlockPlain:
 			if len(b.Succs) != 1 {
-				log.Panicf("plain block %s len(Succs)==%d, want 1", b, len(b.Succs))
+				f.Fatal("plain block %s len(Succs)==%d, want 1", b, len(b.Succs))
 			}
 			if b.Control != nil {
-				log.Panicf("plain block %s has non-nil control %s", b, b.Control.LongString())
+				f.Fatal("plain block %s has non-nil control %s", b, b.Control.LongString())
 			}
 		case BlockIf:
 			if len(b.Succs) != 2 {
-				log.Panicf("if block %s len(Succs)==%d, want 2", b, len(b.Succs))
+				f.Fatal("if block %s len(Succs)==%d, want 2", b, len(b.Succs))
 			}
 			if b.Control == nil {
-				log.Panicf("if block %s has no control value", b)
+				f.Fatal("if block %s has no control value", b)
 			}
 			if !b.Control.Type.IsBoolean() {
-				log.Panicf("if block %s has non-bool control value %s", b, b.Control.LongString())
+				f.Fatal("if block %s has non-bool control value %s", b, b.Control.LongString())
 			}
 		case BlockCall:
 			if len(b.Succs) != 2 {
-				log.Panicf("call block %s len(Succs)==%d, want 2", b, len(b.Succs))
+				f.Fatal("call block %s len(Succs)==%d, want 2", b, len(b.Succs))
 			}
 			if b.Control == nil {
-				log.Panicf("call block %s has no control value", b)
+				f.Fatal("call block %s has no control value", b)
 			}
 			if !b.Control.Type.IsMemory() {
-				log.Panicf("call block %s has non-memory control value %s", b, b.Control.LongString())
+				f.Fatal("call block %s has non-memory control value %s", b, b.Control.LongString())
 			}
 			if b.Succs[1].Kind != BlockExit {
-				log.Panicf("exception edge from call block %s does not go to exit but %s", b, b.Succs[1])
+				f.Fatal("exception edge from call block %s does not go to exit but %s", b, b.Succs[1])
 			}
 		}
 
 		for _, v := range b.Values {
 			if valueMark[v.ID] {
-				log.Panicf("value %s appears twice!", v.LongString())
+				f.Fatal("value %s appears twice!", v.LongString())
 			}
 			valueMark[v.ID] = true
 
 			if v.Block != b {
-				log.Panicf("%s.block != %s", v, b)
+				f.Fatal("%s.block != %s", v, b)
 			}
 			if v.Op == OpPhi && len(v.Args) != len(b.Preds) {
-				log.Panicf("phi length %s does not match pred length %d for block %s", v.LongString(), len(b.Preds), b)
+				f.Fatal("phi length %s does not match pred length %d for block %s", v.LongString(), len(b.Preds), b)
 			}
 
 			// TODO: check for cycles in values
@@ -113,12 +111,12 @@ func checkFunc(f *Func) {
 
 	for _, id := range f.bid.free {
 		if blockMark[id] {
-			log.Panicf("used block b%d in free list", id)
+			f.Fatal("used block b%d in free list", id)
 		}
 	}
 	for _, id := range f.vid.free {
 		if valueMark[id] {
-			log.Panicf("used value v%d in free list", id)
+			f.Fatal("used value v%d in free list", id)
 		}
 	}
 }

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

@@ -4,10 +4,7 @@
 
 package ssa
 
-import (
+import "log"
-	"fmt"
-	"log"
-)
 
 // Compile is the main entry point for this package.
 // Compile modifies f so that on return:
@@ -18,13 +15,13 @@ import (
 func Compile(f *Func) {
 	// TODO: debugging - set flags to control verbosity of compiler,
 	// which phases to dump IR before/after, etc.
-	fmt.Printf("compiling %s\n", f.Name)
+	f.Log("compiling %s\n", f.Name)
 
 	// hook to print function & phase if panic happens
 	phaseName := "init"
 	defer func() {
 		if phaseName != "" {
-			fmt.Printf("panic during %s while compiling %s\n", phaseName, f.Name)
+			f.Fatal("panic during %s while compiling %s\n", phaseName, f.Name)
 		}
 	}()
 
@@ -33,9 +30,9 @@ func Compile(f *Func) {
 	checkFunc(f)
 	for _, p := range passes {
 		phaseName = p.name
-		fmt.Printf("  pass %s begin\n", p.name)
+		f.Log("  pass %s begin\n", p.name)
 		p.fn(f)
-		fmt.Printf("  pass %s end\n", p.name)
+		f.Log("  pass %s end\n", p.name)
 		printFunc(f)
 		checkFunc(f)
 	}

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

@@ -4,8 +4,6 @@
 
 package ssa
 
-import "log"
-
 type Config struct {
 	arch       string                     // "amd64", etc.
 	ptrSize    int64                      // 4 or 8
@@ -22,6 +20,16 @@ type Frontend interface {
 	// Strings are laid out in read-only memory with one word of pointer,
 	// one word of length, then the contents of the string.
 	StringSym(string) interface{} // returns *gc.Sym
+
+	// Log logs a message from the compiler.
+	Log(string, ...interface{})
+
+	// Fatal reports a compiler error and exits.
+	Fatal(string, ...interface{})
+
+	// Unimplemented reports that the function cannot be compiled.
+	// It will be removed once SSA work is complete.
+	Unimplemented(msg string, args ...interface{})
 }
 
 // NewConfig returns a new configuration object for the given architecture.
@@ -37,7 +45,7 @@ func NewConfig(arch string, fe Frontend) *Config {
 		c.lowerBlock = rewriteBlockAMD64
 		c.lowerValue = rewriteValueAMD64 // TODO(khr): full 32-bit support
 	default:
-		log.Fatalf("arch %s not implemented", arch)
+		fe.Unimplemented("arch %s not implemented", arch)
 	}
 
 	// cache the intptr type in the config
@@ -55,5 +63,9 @@ func (c *Config) NewFunc() *Func {
 	return &Func{Config: c}
 }
 
+func (c *Config) Log(msg string, args ...interface{})           { c.fe.Log(msg, args...) }
+func (c *Config) Fatal(msg string, args ...interface{})         { c.fe.Fatal(msg, args...) }
+func (c *Config) Unimplemented(msg string, args ...interface{}) { c.fe.Unimplemented(msg, args...) }
+
 // TODO(khr): do we really need a separate Config, or can we just
 // store all its fields inside a Func?

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

@@ -4,8 +4,6 @@
 
 package ssa
 
-import "log"
-
 // deadcode removes dead code from f.
 func deadcode(f *Func) {
 
@@ -82,7 +80,7 @@ func deadcode(f *Func) {
 			i++
 		} else {
 			if len(b.Values) > 0 {
-				log.Panicf("live values in unreachable block %v: %v", b, b.Values)
+				b.Fatal("live values in unreachable block %v: %v", b, b.Values)
 			}
 			f.bid.put(b.ID)
 		}
@@ -105,7 +103,7 @@ func removePredecessor(b, c *Block) {
 	if n == 0 {
 		// c is now dead - don't bother working on it
 		if c.Preds[0] != b {
-			log.Panicf("%s.Preds[0]==%s, want %s", c, c.Preds[0], b)
+			b.Fatal("%s.Preds[0]==%s, want %s", c, c.Preds[0], b)
 		}
 		return
 	}

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

@@ -7,7 +7,7 @@ package ssa
 import "testing"
 
 func TestDeadLoop(t *testing.T) {
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	fun := Fun(c, "entry",
 		Bloc("entry",
 			Valu("mem", OpArg, TypeMem, 0, ".mem"),
@@ -37,7 +37,7 @@ func TestDeadLoop(t *testing.T) {
 }
 
 func TestDeadValue(t *testing.T) {
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	fun := Fun(c, "entry",
 		Bloc("entry",
 			Valu("mem", OpArg, TypeMem, 0, ".mem"),
@@ -60,7 +60,7 @@ func TestDeadValue(t *testing.T) {
 }
 
 func TestNeverTaken(t *testing.T) {
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	fun := Fun(c, "entry",
 		Bloc("entry",
 			Valu("cond", OpConst, TypeBool, 0, false),

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

@@ -4,8 +4,6 @@
 
 package ssa
 
-import "log"
-
 // dse does dead-store elimination on the Function.
 // Dead stores are those which are unconditionally followed by
 // another store to the same location, with no intervening load.
@@ -58,12 +56,12 @@ func dse(f *Func) {
 				continue
 			}
 			if last != nil {
-				log.Fatalf("two final stores - simultaneous live stores", last, v)
+				b.Fatal("two final stores - simultaneous live stores", last, v)
 			}
 			last = v
 		}
 		if last == nil {
-			log.Fatalf("no last store found - cycle?")
+			b.Fatal("no last store found - cycle?")
 		}
 
 		// Walk backwards looking for dead stores.  Keep track of shadowed addresses.

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

@@ -9,7 +9,7 @@ import (
 )
 
 func TestDeadStore(t *testing.T) {
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	ptrType := &TypeImpl{Size_: 8, Ptr: true, Name: "testptr"} // dummy for testing
 	fun := Fun(c, "entry",
 		Bloc("entry",
@@ -35,7 +35,7 @@ func TestDeadStore(t *testing.T) {
 }
 func TestDeadStorePhi(t *testing.T) {
 	// make sure we don't get into an infinite loop with phi values.
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	ptrType := &TypeImpl{Size_: 8, Ptr: true, Name: "testptr"} // dummy for testing
 	fun := Fun(c, "entry",
 		Bloc("entry",
@@ -60,7 +60,7 @@ func TestDeadStoreTypes(t *testing.T) {
 	// stronger restriction, that one store can't shadow another unless the
 	// types of the address fields are identical (where identicalness is
 	// decided by the CSE pass).
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	t1 := &TypeImpl{Size_: 8, Ptr: true, Name: "t1"}
 	t2 := &TypeImpl{Size_: 4, Ptr: true, Name: "t2"}
 	fun := Fun(c, "entry",

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

@@ -7,8 +7,6 @@ package ssa
 // This file contains code to compute the dominator tree
 // of a control-flow graph.
 
-import "log"
-
 // postorder computes a postorder traversal ordering for the
 // basic blocks in f.  Unreachable blocks will not appear.
 func postorder(f *Func) []*Block {
@@ -47,7 +45,7 @@ func postorder(f *Func) []*Block {
 				}
 			}
 		default:
-			log.Fatalf("bad stack state %v %d", b, mark[b.ID])
+			b.Fatal("bad stack state %v %d", b, mark[b.ID])
 		}
 	}
 	return order
@@ -73,7 +71,7 @@ func dominators(f *Func) []*Block {
 	// Make the entry block a self-loop
 	idom[f.Entry.ID] = f.Entry
 	if postnum[f.Entry.ID] != len(post)-1 {
-		log.Fatalf("entry block %v not last in postorder", f.Entry)
+		f.Fatal("entry block %v not last in postorder", f.Entry)
 	}
 
 	// Compute relaxation of idom entries

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

@@ -4,13 +4,21 @@
 
 package ssa
 
+import "testing"
+
 var CheckFunc = checkFunc
 var PrintFunc = printFunc
 var Opt = opt
 var Deadcode = deadcode
 
-type DummyFrontend struct{}
+type DummyFrontend struct {
+	t *testing.T
+}
 
-func (d DummyFrontend) StringSym(s string) interface{} {
+func (DummyFrontend) StringSym(s string) interface{} {
 	return nil
 }
+
+func (d DummyFrontend) Log(msg string, args ...interface{})           { d.t.Logf(msg, args...) }
+func (d DummyFrontend) Fatal(msg string, args ...interface{})         { d.t.Fatalf(msg, args...) }
+func (d DummyFrontend) Unimplemented(msg string, args ...interface{}) { d.t.Fatalf(msg, args...) }

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

@@ -4,8 +4,6 @@
 
 package ssa
 
-import "log"
-
 // A Func represents a Go func declaration (or function literal) and
 // its body.  This package compiles each Func independently.
 type Func struct {
@@ -79,7 +77,7 @@ func (b *Block) NewValue0A(line int32, op Op, t Type, aux interface{}) *Value {
 		// Disallow int64 aux values.  They should be in the auxint field instead.
 		// Maybe we want to allow this at some point, but for now we disallow it
 		// to prevent errors like using NewValue1A instead of NewValue1I.
-		log.Fatalf("aux field has int64 type op=%s type=%s aux=%v", op, t, aux)
+		b.Fatal("aux field has int64 type op=%s type=%s aux=%v", op, t, aux)
 	}
 	v := &Value{
 		ID:    b.Func.vid.get(),
@@ -209,3 +207,7 @@ func (f *Func) ConstInt(line int32, t Type, c int64) *Value {
 	// TODO: cache?
 	return f.Entry.NewValue0I(line, OpConst, t, c)
 }
+
+func (f *Func) Log(msg string, args ...interface{})           { f.Config.Log(msg, args...) }
+func (f *Func) Fatal(msg string, args ...interface{})         { f.Config.Fatal(msg, args...) }
+func (f *Func) Unimplemented(msg string, args ...interface{}) { f.Config.Unimplemented(msg, args...) }

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

@@ -37,7 +37,7 @@ package ssa
 //                the parser can be used instead of Fun.
 
 import (
-	"log"
+	"fmt"
 	"reflect"
 	"testing"
 )
@@ -161,7 +161,7 @@ func Fun(c *Config, entry string, blocs ...bloc) fun {
 		if c.control != "" {
 			cval, ok := values[c.control]
 			if !ok {
-				log.Panicf("control value for block %s missing", bloc.name)
+				f.Fatal("control value for block %s missing", bloc.name)
 			}
 			b.Control = cval
 		}
@@ -171,7 +171,7 @@ func Fun(c *Config, entry string, blocs ...bloc) fun {
 			for _, arg := range valu.args {
 				a, ok := values[arg]
 				if !ok {
-					log.Panicf("arg %s missing for value %s in block %s",
+					b.Fatal("arg %s missing for value %s in block %s",
 						arg, valu.name, bloc.name)
 				}
 				v.AddArg(a)
@@ -197,7 +197,7 @@ func Bloc(name string, entries ...interface{}) bloc {
 		case ctrl:
 			// there should be exactly one Ctrl entry.
 			if seenCtrl {
-				log.Panicf("already seen control for block %s", name)
+				panic(fmt.Sprintf("already seen control for block %s", name))
 			}
 			b.control = v
 			seenCtrl = true
@@ -206,7 +206,7 @@ func Bloc(name string, entries ...interface{}) bloc {
 		}
 	}
 	if !seenCtrl {
-		log.Panicf("block %s doesn't have control", b.name)
+		panic(fmt.Sprintf("block %s doesn't have control", b.name))
 	}
 	return b
 }
@@ -262,7 +262,7 @@ func addEdge(b, c *Block) {
 }
 
 func TestArgs(t *testing.T) {
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	fun := Fun(c, "entry",
 		Bloc("entry",
 			Valu("a", OpConst, TypeInt64, 14, nil),
@@ -282,7 +282,7 @@ func TestArgs(t *testing.T) {
 }
 
 func TestEquiv(t *testing.T) {
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	equivalentCases := []struct{ f, g fun }{
 		// simple case
 		{

src/cmd/compile/internal/ssa/gen/generic.rules

@@ -32,7 +32,7 @@
 
 // indexing operations
 // Note: bounds check has already been done
-(ArrayIndex (Load ptr mem) idx) -> (Load (PtrIndex <ptr.Type.Elem().Elem().PtrTo()> ptr idx) mem)
+(ArrayIndex (Load ptr mem) idx) -> (Load (PtrIndex <v.Type.PtrTo()> ptr idx) mem)
 (PtrIndex <t> ptr idx) -> (Add ptr (Mul <config.Uintptr> idx (Const <config.Uintptr> [t.Elem().Size()])))
 
 // big-object moves

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

@@ -4,8 +4,6 @@
 
 package ssa
 
-import "log"
-
 // layout orders basic blocks in f with the goal of minimizing control flow instructions.
 // After this phase returns, the order of f.Blocks matters and is the order
 // in which those blocks will appear in the assembly output.
@@ -82,7 +80,7 @@ blockloop:
 				continue blockloop
 			}
 		}
-		log.Panicf("no block available for layout")
+		b.Fatal("no block available for layout")
 	}
 	f.Blocks = order
 }

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

@@ -4,8 +4,6 @@
 
 package ssa
 
-import "log"
-
 // convert to machine-dependent ops
 func lower(f *Func) {
 	// repeat rewrites until we find no more rewrites
@@ -15,7 +13,7 @@ func lower(f *Func) {
 	for _, b := range f.Blocks {
 		for _, v := range b.Values {
 			if opcodeTable[v.Op].generic && v.Op != OpFP && v.Op != OpSP && v.Op != OpArg && v.Op != OpCopy && v.Op != OpPhi {
-				log.Panicf("%s not lowered", v.LongString())
+				f.Unimplemented("%s not lowered", v.LongString())
 			}
 		}
 	}

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

@@ -8,11 +8,10 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"os"
 )
 
 func printFunc(f *Func) {
-	fprintFunc(os.Stdout, f)
+	f.Log("%s", f.String())
 }
 
 func (f *Func) String() string {

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

@@ -4,11 +4,7 @@
 
 package ssa
 
-import (
+import "sort"
-	"fmt"
-	"log"
-	"sort"
-)
 
 func setloc(home []Location, v *Value, loc Location) []Location {
 	for v.ID >= ID(len(home)) {
@@ -353,7 +349,7 @@ func regalloc(f *Func) {
 		if b.Kind == BlockCall {
 			call = b.Control
 			if call != b.Values[len(b.Values)-1] {
-				log.Fatalf("call not at end of block %b %v", b, call)
+				b.Fatal("call not at end of block %b %v", b, call)
 			}
 			b.Values = b.Values[:len(b.Values)-1]
 			// TODO: do this for all control types?
@@ -423,7 +419,7 @@ func live(f *Func) [][]ID {
 	t := newSparseSet(f.NumValues())
 	for {
 		for _, b := range f.Blocks {
-			fmt.Printf("live %s %v\n", b, live[b.ID])
+			f.Log("live %s %v\n", b, live[b.ID])
 		}
 		changed := false
 

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

@@ -4,7 +4,7 @@
 
 package ssa
 
-import "log"
+import "fmt"
 
 func applyRewrite(f *Func, rb func(*Block) bool, rv func(*Value, *Config) bool) {
 	// repeat rewrites until we find no more rewrites
@@ -12,11 +12,10 @@ func applyRewrite(f *Func, rb func(*Block) bool, rv func(*Value, *Config) bool)
 	var curv *Value
 	defer func() {
 		if curb != nil {
-			log.Printf("panic during rewrite of block %s\n", curb.LongString())
+			curb.Fatal("panic during rewrite of block %s\n", curb.LongString())
 		}
 		if curv != nil {
-			log.Printf("panic during rewrite of value %s\n", curv.LongString())
+			curv.Fatal("panic during rewrite of value %s\n", curv.LongString())
-			panic("rewrite failed")
 			// TODO(khr): print source location also
 		}
 	}()
@@ -90,12 +89,12 @@ func typeSize(t Type) int64 {
 	return t.Size()
 }
 
-// addOff adds two int64 offsets.  Fails if wraparound happens.
+// addOff adds two int64 offsets. Fails if wraparound happens.
 func addOff(x, y int64) int64 {
 	z := x + y
 	// x and y have same sign and z has a different sign => overflow
 	if x^y >= 0 && x^z < 0 {
-		log.Panicf("offset overflow %d %d\n", x, y)
+		panic(fmt.Sprintf("offset overflow %d %d", x, y))
 	}
 	return z
 }

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

@@ -34,10 +34,10 @@ func rewriteValuegeneric(v *Value, config *Config) bool {
 	case OpArrayIndex:
 		// match: (ArrayIndex (Load ptr mem) idx)
 		// cond:
-		// result: (Load (PtrIndex <ptr.Type.Elem().Elem().PtrTo()> ptr idx) mem)
+		// result: (Load (PtrIndex <v.Type.PtrTo()> ptr idx) mem)
 		{
 			if v.Args[0].Op != OpLoad {
-				goto end3809f4c52270a76313e4ea26e6f0b753
+				goto end4894dd7b58383fee5f8a92be08437c33
 			}
 			ptr := v.Args[0].Args[0]
 			mem := v.Args[0].Args[1]
@@ -47,15 +47,15 @@ func rewriteValuegeneric(v *Value, config *Config) bool {
 			v.Aux = nil
 			v.resetArgs()
 			v0 := v.Block.NewValue0(v.Line, OpPtrIndex, TypeInvalid)
-			v0.Type = ptr.Type.Elem().Elem().PtrTo()
+			v0.Type = v.Type.PtrTo()
 			v0.AddArg(ptr)
 			v0.AddArg(idx)
 			v.AddArg(v0)
 			v.AddArg(mem)
 			return true
 		}
-		goto end3809f4c52270a76313e4ea26e6f0b753
+		goto end4894dd7b58383fee5f8a92be08437c33
-	end3809f4c52270a76313e4ea26e6f0b753:
+	end4894dd7b58383fee5f8a92be08437c33:
 		;
 	case OpConst:
 		// match: (Const <t> {s})

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

@@ -7,7 +7,7 @@ package ssa
 import "testing"
 
 func TestSchedule(t *testing.T) {
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	cases := []fun{
 		Fun(c, "entry",
 			Bloc("entry",

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

@@ -9,7 +9,7 @@ import (
 )
 
 func TestShiftConstAMD64(t *testing.T) {
-	c := NewConfig("amd64", DummyFrontend{})
+	c := NewConfig("amd64", DummyFrontend{t})
 	fun := makeConstShiftFunc(c, 18, OpLsh, TypeUInt64)
 	checkOpcodeCounts(t, fun.f, map[Op]int{OpAMD64SHLQconst: 1, OpAMD64CMPQconst: 0, OpAMD64ANDQconst: 0})
 	fun = makeConstShiftFunc(c, 66, OpLsh, TypeUInt64)

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

@@ -4,8 +4,6 @@
 
 package ssa
 
-import "log"
-
 // stackalloc allocates storage in the stack frame for
 // all Values that did not get a register.
 func stackalloc(f *Func) {
@@ -79,7 +77,7 @@ func stackalloc(f *Func) {
 		for _, v := range b.Values {
 			if v.Op == OpFP {
 				if fp != nil {
-					log.Panicf("multiple FP ops: %s %s", fp, v)
+					b.Fatal("multiple FP ops: %s %s", fp, v)
 				}
 				fp = v
 			}
@@ -99,12 +97,12 @@ func stackalloc(f *Func) {
 				case OpAMD64LEAQ, OpAMD64MOVQload, OpAMD64MOVQstore, OpAMD64MOVLload, OpAMD64MOVLstore, OpAMD64MOVWload, OpAMD64MOVWstore, OpAMD64MOVBload, OpAMD64MOVBstore, OpAMD64MOVQloadidx8:
 					if v.Op == OpAMD64MOVQloadidx8 && i == 1 {
 						// Note: we could do it, but it is probably an error
-						log.Panicf("can't do FP->SP adjust on index slot of load %s", v.Op)
+						f.Fatal("can't do FP->SP adjust on index slot of load %s", v.Op)
 					}
 					// eg: (MOVQload [c] (FP) mem) -> (MOVQload [c+n] (SP) mem)
 					v.AuxInt = addOff(v.AuxInt, n)
 				default:
-					log.Panicf("can't do FP->SP adjust on %s", v.Op)
+					f.Unimplemented("can't do FP->SP adjust on %s", v.Op)
 					// TODO: OpCopy -> ADDQ
 				}
 			}

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

@@ -106,3 +106,7 @@ func (v *Value) resetArgs() {
 	v.argstorage[1] = nil
 	v.Args = v.argstorage[:0]
 }
+
+func (v *Value) Log(msg string, args ...interface{})           { v.Block.Log(msg, args...) }
+func (v *Value) Fatal(msg string, args ...interface{})         { v.Block.Fatal(msg, args...) }
+func (v *Value) Unimplemented(msg string, args ...interface{}) { v.Block.Unimplemented(msg, args...) }