5g, 6g, 8g: registerize variables again

My previous CL:

changeset:   9645:ce2e5f44b310
user:        Russ Cox <rsc@golang.org>
date:        Tue Sep 06 10:24:21 2011 -0400
summary:     gc: unify stack frame layout

introduced a bug wherein no variables were
being registerized, making Go programs 2-3x
slower than they had been before.

This CL fixes that bug (along with some others
it was hiding) and adds a test that optimization
makes at least one test case faster.

R=ken2
CC=golang-dev
https://golang.org/cl/5174045

src/cmd/5g/gobj.c

@@ -307,6 +307,7 @@ datastring(char *s, int len, Addr *a)
 	a->offset = widthptr+4;  // skip header
 	a->reg = NREG;
 	a->sym = sym;
+	a->node = sym->def;
 }
 
 /*
@@ -325,6 +326,7 @@ datagostring(Strlit *sval, Addr *a)
 	a->offset = 0;  // header
 	a->reg = NREG;
 	a->sym = sym;
+	a->node = sym->def;
 }
 
 void

src/cmd/5g/gsubr.c

@@ -512,6 +512,7 @@ nodarg(Type *t, int fp)
 		fatal("nodarg: offset not computed for %T", t);
 	n->xoffset = t->width;
 	n->addable = 1;
+	n->orig = t->nname;
 
 fp:
 	switch(fp) {
@@ -1263,6 +1264,7 @@ naddr(Node *n, Addr *a, int canemitcode)
 		a->sym = n->left->sym;
 		a->type = D_OREG;
 		a->name = D_PARAM;
+		a->node = n->left->orig;
 		break;
 
 	case ONAME:
@@ -1275,6 +1277,9 @@ naddr(Node *n, Addr *a, int canemitcode)
 		}
 		a->offset = n->xoffset;
 		a->sym = n->sym;
+		a->node = n->orig;
+		//if(a->node >= (Node*)&n)
+		//	fatal("stack node");
 		if(a->sym == S)
 			a->sym = lookup(".noname");
 		if(n->method) {
@@ -1293,8 +1298,6 @@ naddr(Node *n, Addr *a, int canemitcode)
 			break;
 		case PAUTO:
 			a->name = D_AUTO;
-			if (n->sym)
-				a->node = n->orig;
 			break;
 		case PPARAM:
 		case PPARAMOUT:

src/cmd/5g/reg.c

@@ -92,8 +92,8 @@ setoutvar(void)
 			ovar.b[z] |= bit.b[z];
 		t = structnext(&save);
 	}
-//if(bany(b))
+//if(bany(ovar))
-//print("ovars = %Q\n", &ovar);
+//print("ovar = %Q\n", ovar);
 }
 
 void
@@ -911,10 +911,12 @@ mkvar(Reg *r, Adr *a)
 	}
 
 	node = a->node;
-	if(node == N || node->op != ONAME || node->orig != N)
+	if(node == N || node->op != ONAME || node->orig == N)
 		goto none;
 	node = node->orig;
-	if(node->sym->name[0] == '.')
+	if(node->orig != node)
+		fatal("%D: bad node", a);
+	if(node->sym == S || node->sym->name[0] == '.')
 		goto none;
 	et = a->etype;
 	o = a->offset;
@@ -1571,7 +1573,7 @@ dumpone(Reg *r)
 		if(bany(&r->refahead))
 			print(" ra:%Q ", r->refahead);
 		if(bany(&r->calbehind))
-			print("cb:%Q ", r->calbehind);
+			print(" cb:%Q ", r->calbehind);
 		if(bany(&r->calahead))
 			print(" ca:%Q ", r->calahead);
 		if(bany(&r->regdiff))

src/cmd/6g/gobj.c

@@ -310,6 +310,7 @@ datastring(char *s, int len, Addr *a)
 	sym = stringsym(s, len);
 	a->type = D_EXTERN;
 	a->sym = sym;
+	a->node = sym->def;
 	a->offset = widthptr+4;  // skip header
 	a->etype = TINT32;
 }
@@ -326,6 +327,7 @@ datagostring(Strlit *sval, Addr *a)
 	sym = stringsym(sval->s, sval->len);
 	a->type = D_EXTERN;
 	a->sym = sym;
+	a->node = sym->def;
 	a->offset = 0;  // header
 	a->etype = TINT32;
 }

src/cmd/6g/gsubr.c

@@ -485,6 +485,7 @@ nodarg(Type *t, int fp)
 		fatal("nodarg: offset not computed for %T", t);
 	n->xoffset = t->width;
 	n->addable = 1;
+	n->orig = t->nname;
 
 fp:
 	switch(fp) {
@@ -1119,6 +1120,7 @@ naddr(Node *n, Addr *a, int canemitcode)
 		a->offset = n->xoffset;
 		a->sym = n->left->sym;
 		a->type = D_PARAM;
+		a->node = n->left->orig;
 		break;
 
 	case ONAME:
@@ -1131,6 +1133,9 @@ naddr(Node *n, Addr *a, int canemitcode)
 		}
 		a->offset = n->xoffset;
 		a->sym = n->sym;
+		a->node = n->orig;
+		//if(a->node >= (Node*)&n)
+		//	fatal("stack node");
 		if(a->sym == S)
 			a->sym = lookup(".noname");
 		if(n->method) {
@@ -1148,8 +1153,6 @@ naddr(Node *n, Addr *a, int canemitcode)
 			break;
 		case PAUTO:
 			a->type = D_AUTO;
-			if (n->sym)
-				a->node = n->orig;
 			break;
 		case PPARAM:
 		case PPARAMOUT:

src/cmd/6g/reg.c

@@ -89,8 +89,8 @@ setoutvar(void)
 			ovar.b[z] |= bit.b[z];
 		t = structnext(&save);
 	}
-//if(bany(b))
+//if(bany(&ovar))
-//print("ovars = %Q\n", &ovar);
+//print("ovars = %Q\n", ovar);
 }
 
 static void
@@ -968,11 +968,14 @@ mkvar(Reg *r, Adr *a)
 		n = t;
 		break;
 	}
+
 	node = a->node;
-	if(node == N || node->op != ONAME || node->orig != N)
+	if(node == N || node->op != ONAME || node->orig == N)
 		goto none;
 	node = node->orig;
-	if(node->sym->name[0] == '.')
+	if(node->orig != node)
+		fatal("%D: bad node", a);
+	if(node->sym == S || node->sym->name[0] == '.')
 		goto none;
 	et = a->etype;
 	o = a->offset;
@@ -1622,7 +1625,7 @@ dumpone(Reg *r)
 		if(bany(&r->refahead))
 			print(" ra:%Q ", r->refahead);
 		if(bany(&r->calbehind))
-			print("cb:%Q ", r->calbehind);
+			print(" cb:%Q ", r->calbehind);
 		if(bany(&r->calahead))
 			print(" ca:%Q ", r->calahead);
 		if(bany(&r->regdiff))

src/cmd/8g/gobj.c

@@ -308,6 +308,7 @@ datastring(char *s, int len, Addr *a)
 	sym = stringsym(s, len);
 	a->type = D_EXTERN;
 	a->sym = sym;
+	a->node = sym->def;
 	a->offset = widthptr+4;  // skip header
 	a->etype = TINT32;
 }
@@ -324,6 +325,7 @@ datagostring(Strlit *sval, Addr *a)
 	sym = stringsym(sval->s, sval->len);
 	a->type = D_EXTERN;
 	a->sym = sym;
+	a->node = sym->def;
 	a->offset = 0;  // header
 	a->etype = TINT32;
 }

src/cmd/8g/gsubr.c

@@ -964,6 +964,7 @@ nodarg(Type *t, int fp)
 			fatal("nodarg: offset not computed for %T", t);
 		n->xoffset = t->width;
 		n->addable = 1;
+		n->orig = t->nname;
 		break;
 	}
 
@@ -1152,6 +1153,7 @@ memname(Node *n, Type *t)
 	strcpy(namebuf, n->sym->name);
 	namebuf[0] = '.';	// keep optimizer from registerizing
 	n->sym = lookup(namebuf);
+	n->orig->sym = n->sym;
 }
 
 void
@@ -1828,6 +1830,7 @@ naddr(Node *n, Addr *a, int canemitcode)
 		a->offset = n->xoffset;
 		a->sym = n->left->sym;
 		a->type = D_PARAM;
+		a->node = n->left->orig;
 		break;
 
 	case ONAME:
@@ -1840,6 +1843,9 @@ naddr(Node *n, Addr *a, int canemitcode)
 		}
 		a->offset = n->xoffset;
 		a->sym = n->sym;
+		a->node = n->orig;
+		//if(a->node >= (Node*)&n)
+		//	fatal("stack node");
 		if(a->sym == S)
 			a->sym = lookup(".noname");
 		if(n->method) {
@@ -1857,8 +1863,6 @@ naddr(Node *n, Addr *a, int canemitcode)
 			break;
 		case PAUTO:
 			a->type = D_AUTO;
-			if (n->sym)
-				a->node = n->orig;
 			break;
 		case PPARAM:
 		case PPARAMOUT:

src/cmd/8g/reg.c

@@ -89,8 +89,8 @@ setoutvar(void)
 			ovar.b[z] |= bit.b[z];
 		t = structnext(&save);
 	}
-//if(bany(b))
+//if(bany(ovar))
-//print("ovars = %Q\n", &ovar);
+//print("ovars = %Q\n", ovar);
 }
 
 static void
@@ -848,10 +848,12 @@ mkvar(Reg *r, Adr *a)
 	}
 
 	node = a->node;
-	if(node == N || node->op != ONAME || node->orig != N)
+	if(node == N || node->op != ONAME || node->orig == N)
 		goto none;
 	node = node->orig;
-	if(node->sym->name[0] == '.')
+	if(node->orig != node)
+		fatal("%D: bad node", a);
+	if(node->sym == S || node->sym->name[0] == '.')
 		goto none;
 	et = a->etype;
 	o = a->offset;
@@ -1482,7 +1484,7 @@ dumpone(Reg *r)
 		if(bany(&r->refahead))
 			print(" ra:%Q ", r->refahead);
 		if(bany(&r->calbehind))
-			print("cb:%Q ", r->calbehind);
+			print(" cb:%Q ", r->calbehind);
 		if(bany(&r->calahead))
 			print(" ca:%Q ", r->calahead);
 		if(bany(&r->regdiff))

src/cmd/gc/bits.c

@@ -151,9 +151,9 @@ Qconv(Fmt *fp)
 		else
 			fmtprint(fp, " ");
 		if(var[i].node == N || var[i].node->sym == S)
-			fmtprint(fp, "$%lld", var[i].offset);
+			fmtprint(fp, "$%lld", i);
 		else {
-			fmtprint(fp, var[i].node->sym->name);
+			fmtprint(fp, "%s", var[i].node->sym->name);
 			if(var[i].offset != 0)
 				fmtprint(fp, "%+lld", (vlong)var[i].offset);
 		}

src/cmd/gc/gen.c

@@ -805,6 +805,7 @@ tempname(Node *nn, Type *t)
 	s = lookup(namebuf);
 	n = nod(ONAME, N, N);
 	n->sym = s;
+	s->def = n;
 	n->type = t;
 	n->class = PAUTO;
 	n->addable = 1;

src/cmd/gc/obj.c

@@ -267,6 +267,7 @@ stringsym(char *s, int len)
 	if(sym->flags & SymUniq)
 		return sym;
 	sym->flags |= SymUniq;
+	sym->def = newname(sym);
 
 	off = 0;
 	

test/fixedbugs/bug369.dir/pkg.go

@@ -0,0 +1,15 @@
+// Copyright 2011 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 pkg
+
+func NonASCII(b []byte, i int) int {
+	for i = 0; i < len(b); i++ {
+		if b[i] >= 0x80 {
+			break
+		}
+	}
+	return i
+}
+

test/fixedbugs/bug369.go

@@ -0,0 +1,57 @@
+// $G -N -o slow.$A $D/bug369.dir/pkg.go &&
+// $G -o fast.$A $D/bug369.dir/pkg.go &&
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2011 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.
+
+// Test that compiling with optimization turned on produces faster code.
+
+package main
+
+import (
+	"flag"
+	"os"
+	"runtime"
+	"testing"
+
+	fast "./fast"
+	slow "./slow"
+)
+
+var buf = make([]byte, 1048576)
+
+func BenchmarkFastNonASCII(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		fast.NonASCII(buf, 0)
+	}
+}
+
+func BenchmarkSlowNonASCII(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		slow.NonASCII(buf, 0)
+	}
+}
+
+func main() {
+	os.Args = []string{os.Args[0], "-test.benchtime=0.1"}
+	flag.Parse()
+	
+	rslow := testing.Benchmark(BenchmarkSlowNonASCII)
+	rfast := testing.Benchmark(BenchmarkFastNonASCII)
+	tslow := rslow.NsPerOp()
+	tfast := rfast.NsPerOp()
+
+	// Optimization should be good for at least 2x, but be forgiving.
+	// On the ARM simulator we see closer to 1.5x.
+	speedup := float64(tslow)/float64(tfast)
+	want := 1.8
+	if runtime.GOARCH == "arm" {
+		want = 1.3
+	}
+	if speedup < want {
+		println("fast:", tfast, "slow:", tslow, "speedup:", speedup, "want:", want)
+		println("not fast enough")
+	}
+}