1 files changed, 192 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/print.go b/src/cmd/compile/internal/ssa/print.go
new file mode 100644
index 0000000..0d3b5d9
--- /dev/null
+++ b/src/cmd/compile/internal/ssa/print.go
@@ -0,0 +1,192 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ssa
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"cmd/internal/notsha256"
+	"cmd/internal/src"
+)
+
+func printFunc(f *Func) {
+	f.Logf("%s", f)
+}
+
+func hashFunc(f *Func) []byte {
+	h := notsha256.New()
+	p := stringFuncPrinter{w: h, printDead: true}
+	fprintFunc(p, f)
+	return h.Sum(nil)
+}
+
+func (f *Func) String() string {
+	var buf strings.Builder
+	p := stringFuncPrinter{w: &buf, printDead: true}
+	fprintFunc(p, f)
+	return buf.String()
+}
+
+// rewriteHash returns a hash of f suitable for detecting rewrite cycles.
+func (f *Func) rewriteHash() string {
+	h := notsha256.New()
+	p := stringFuncPrinter{w: h, printDead: false}
+	fprintFunc(p, f)
+	return fmt.Sprintf("%x", h.Sum(nil))
+}
+
+type funcPrinter interface {
+	header(f *Func)
+	startBlock(b *Block, reachable bool)
+	endBlock(b *Block, reachable bool)
+	value(v *Value, live bool)
+	startDepCycle()
+	endDepCycle()
+	named(n LocalSlot, vals []*Value)
+}
+
+type stringFuncPrinter struct {
+	w         io.Writer
+	printDead bool
+}
+
+func (p stringFuncPrinter) header(f *Func) {
+	fmt.Fprint(p.w, f.Name)
+	fmt.Fprint(p.w, " ")
+	fmt.Fprintln(p.w, f.Type)
+}
+
+func (p stringFuncPrinter) startBlock(b *Block, reachable bool) {
+	if !p.printDead && !reachable {
+		return
+	}
+	fmt.Fprintf(p.w, "  b%d:", b.ID)
+	if len(b.Preds) > 0 {
+		io.WriteString(p.w, " <-")
+		for _, e := range b.Preds {
+			pred := e.b
+			fmt.Fprintf(p.w, " b%d", pred.ID)
+		}
+	}
+	if !reachable {
+		fmt.Fprint(p.w, " DEAD")
+	}
+	io.WriteString(p.w, "\n")
+}
+
+func (p stringFuncPrinter) endBlock(b *Block, reachable bool) {
+	if !p.printDead && !reachable {
+		return
+	}
+	fmt.Fprintln(p.w, "    "+b.LongString())
+}
+
+func StmtString(p src.XPos) string {
+	linenumber := "(?) "
+	if p.IsKnown() {
+		pfx := ""
+		if p.IsStmt() == src.PosIsStmt {
+			pfx = "+"
+		}
+		if p.IsStmt() == src.PosNotStmt {
+			pfx = "-"
+		}
+		linenumber = fmt.Sprintf("(%s%d) ", pfx, p.Line())
+	}
+	return linenumber
+}
+
+func (p stringFuncPrinter) value(v *Value, live bool) {
+	if !p.printDead && !live {
+		return
+	}
+	fmt.Fprintf(p.w, "    %s", StmtString(v.Pos))
+	fmt.Fprint(p.w, v.LongString())
+	if !live {
+		fmt.Fprint(p.w, " DEAD")
+	}
+	fmt.Fprintln(p.w)
+}
+
+func (p stringFuncPrinter) startDepCycle() {
+	fmt.Fprintln(p.w, "dependency cycle!")
+}
+
+func (p stringFuncPrinter) endDepCycle() {}
+
+func (p stringFuncPrinter) named(n LocalSlot, vals []*Value) {
+	fmt.Fprintf(p.w, "name %s: %v\n", n, vals)
+}
+
+func fprintFunc(p funcPrinter, f *Func) {
+	reachable, live := findlive(f)
+	defer f.Cache.freeBoolSlice(live)
+	p.header(f)
+	printed := make([]bool, f.NumValues())
+	for _, b := range f.Blocks {
+		p.startBlock(b, reachable[b.ID])
+
+		if f.scheduled {
+			// Order of Values has been decided - print in that order.
+			for _, v := range b.Values {
+				p.value(v, live[v.ID])
+				printed[v.ID] = true
+			}
+			p.endBlock(b, reachable[b.ID])
+			continue
+		}
+
+		// print phis first since all value cycles contain a phi
+		n := 0
+		for _, v := range b.Values {
+			if v.Op != OpPhi {
+				continue
+			}
+			p.value(v, live[v.ID])
+			printed[v.ID] = true
+			n++
+		}
+
+		// print rest of values in dependency order
+		for n < len(b.Values) {
+			m := n
+		outer:
+			for _, v := range b.Values {
+				if printed[v.ID] {
+					continue
+				}
+				for _, w := range v.Args {
+					// w == nil shouldn't happen, but if it does,
+					// don't panic; we'll get a better diagnosis later.
+					if w != nil && w.Block == b && !printed[w.ID] {
+						continue outer
+					}
+				}
+				p.value(v, live[v.ID])
+				printed[v.ID] = true
+				n++
+			}
+			if m == n {
+				p.startDepCycle()
+				for _, v := range b.Values {
+					if printed[v.ID] {
+						continue
+					}
+					p.value(v, live[v.ID])
+					printed[v.ID] = true
+					n++
+				}
+				p.endDepCycle()
+			}
+		}
+
+		p.endBlock(b, reachable[b.ID])
+	}
+	for _, name := range f.Names {
+		p.named(*name, f.NamedValues[*name])
+	}
+}