5g/6g/8g: fix double function call in slice

Fixes issue 654.

R=ken2
CC=golang-dev
http://codereview.appspot.com/310041

7 files changed, 105 insertions, 96 deletions

diff --git a/src/cmd/5g/ggen.c b/src/cmd/5g/ggen.c
index 758e140dc..e2313d85b 100644
--- a/src/cmd/5g/ggen.c
+++ b/src/cmd/5g/ggen.c
@@ -810,9 +810,9 @@ int
 cgen_inline(Node *n, Node *res)
 {
 	Node nodes[5];
-	Node n1, n2, n3, nres, nnode0, ntemp;
+	Node n1, n2, n3, nres, ntemp;
 	vlong v;
-	int i, narg, bad;
+	int i, narg;
 
 	if(n->op != OCALLFUNC)
 		goto no;
@@ -926,47 +926,39 @@ slicearray:
 	return 1;
 
 sliceslice:
-	getargs(n->list, nodes, narg);
-
-	nres = *res;		// result
-	nnode0 = nodes[0];	// input slice
-	if(!sleasy(res) || !sleasy(&nodes[0])) {
-		bad = 0;
-		if(res->ullman >= UINF)
-			bad = 1;
-		for(i=0; i<narg; i++) {
-			if(nodes[i].ullman >= UINF)
-				bad = 1;
-			if(nodes[i].op == OREGISTER)
-				regfree(&nodes[i]);
-		}
-
-		if(bad)
-			goto no;
-
+	ntemp.op = OXXX;
+	if(!sleasy(n->list->n->right)) {
+		Node *n0;
+		
+		n0 = n->list->n->right;
 		tempname(&ntemp, res->type);
-		if(!sleasy(&nodes[0])) {
-			cgen(&nodes[0], &ntemp);
-			nnode0 = ntemp;
-		}
+		cgen(n0, &ntemp);
+		n->list->n->right = &ntemp;
+		getargs(n->list, nodes, narg);
+		n->list->n->right = n0;
+	} else
 		getargs(n->list, nodes, narg);
-		if(!sleasy(res))
-			nres = ntemp;
+
+	nres = *res;		// result
+	if(!sleasy(res)) {
+		if(ntemp.op == OXXX)
+			tempname(&ntemp, res->type);
+		nres = ntemp;
 	}
-	
+
 	if(narg == 3) {	// old[lb:]
 		// move width to where it would be for old[lb:hb]
 		nodes[3] = nodes[2];
 		nodes[2].op = OXXX;
 		
 		// if(lb[1] > old.nel[0]) goto throw;
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.xoffset += Array_nel;
 		n2.type = types[TUINT32];
 		cmpandthrow(&nodes[1], &n2);
 
 		// ret.nel = old.nel[0]-lb[1];
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.type = types[TUINT32];
 		n2.xoffset += Array_nel;
 	
@@ -982,7 +974,7 @@ sliceslice:
 		regfree(&n1);
 	} else {	// old[lb:hb]
 		// if(hb[2] > old.cap[0]) goto throw;
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.xoffset += Array_cap;
 		n2.type = types[TUINT32];
 		cmpandthrow(&nodes[2], &n2);
@@ -1011,7 +1003,7 @@ sliceslice:
 	}
 
 	// ret.cap = old.cap[0]-lb[1]; (uses hb[2])
-	n2 = nnode0;
+	n2 = nodes[0];
 	n2.type = types[TUINT32];
 	n2.xoffset += Array_cap;
 
@@ -1027,7 +1019,7 @@ sliceslice:
 	regfree(&n1);
 
 	// ret.array = old.array[0]+lb[1]*width[3]; (uses lb[1])
-	n2 = nnode0;
+	n2 = nodes[0];
 	n2.type = types[tptr];
 	n2.xoffset += Array_array;
 	regalloc(&n3, types[tptr], N);
diff --git a/src/cmd/6g/ggen.c b/src/cmd/6g/ggen.c
index 45fd17b27..99a4aea04 100644
--- a/src/cmd/6g/ggen.c
+++ b/src/cmd/6g/ggen.c
@@ -1138,9 +1138,9 @@ int
 cgen_inline(Node *n, Node *res)
 {
 	Node nodes[5];
-	Node n1, n2, nres, nnode0, ntemp;
+	Node n1, n2, nres, ntemp;
 	vlong v;
-	int i, narg, bad;
+	int i, narg;
 
 	if(n->op != OCALLFUNC)
 		goto no;
@@ -1245,46 +1245,38 @@ slicearray:
 	return 1;
 
 sliceslice:
-	getargs(n->list, nodes, narg);
-
-	nres = *res;		// result
-	nnode0 = nodes[0];	// input slice
-	if(!sleasy(res) || !sleasy(&nodes[0])) {
-		bad = 0;
-		if(res->ullman >= UINF)
-			bad = 1;
-		for(i=0; i<narg; i++) {
-			if(nodes[i].ullman >= UINF)
-				bad = 1;
-			if(nodes[i].op == OREGISTER)
-				regfree(&nodes[i]);
-		}
-
-		if(bad)
-			goto no;
-
+	ntemp.op = OXXX;
+	if(!sleasy(n->list->n->right)) {
+		Node *n0;
+		
+		n0 = n->list->n->right;
 		tempname(&ntemp, res->type);
-		if(!sleasy(&nodes[0])) {
-			cgen(&nodes[0], &ntemp);
-			nnode0 = ntemp;
-		}
+		cgen(n0, &ntemp);
+		n->list->n->right = &ntemp;
+		getargs(n->list, nodes, narg);
+		n->list->n->right = n0;
+	} else
 		getargs(n->list, nodes, narg);
-		if(!sleasy(res))
-			nres = ntemp;
+
+	nres = *res;		// result
+	if(!sleasy(res)) {
+		if(ntemp.op == OXXX)
+			tempname(&ntemp, res->type);
+		nres = ntemp;
 	}
-	
+
 	if(narg == 3) {	// old[lb:]
 		// move width to where it would be for old[lb:hb]
 		nodes[3] = nodes[2];
 		nodes[2].op = OXXX;
 		
 		// if(lb[1] > old.nel[0]) goto throw;
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.xoffset += Array_nel;
 		cmpandthrow(&nodes[1], &n2);
 
 		// ret.nel = old.nel[0]-lb[1];
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.xoffset += Array_nel;
 	
 		regalloc(&n1, types[TUINT32], N);
@@ -1298,7 +1290,7 @@ sliceslice:
 		regfree(&n1);
 	} else {	// old[lb:hb]
 		// if(hb[2] > old.cap[0]) goto throw;
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.xoffset += Array_cap;
 		cmpandthrow(&nodes[2], &n2);
 
@@ -1325,7 +1317,7 @@ sliceslice:
 	}
 
 	// ret.cap = old.cap[0]-lb[1]; (uses hb[2])
-	n2 = nnode0;
+	n2 = nodes[0];
 	n2.xoffset += Array_cap;
 
 	regalloc(&n1, types[TUINT32], &nodes[2]);
@@ -1339,7 +1331,7 @@ sliceslice:
 	regfree(&n1);
 
 	// ret.array = old.array[0]+lb[1]*width[3]; (uses lb[1])
-	n2 = nnode0;
+	n2 = nodes[0];
 	n2.xoffset += Array_array;
 
 	regalloc(&n1, types[tptr], &nodes[1]);
diff --git a/src/cmd/8g/gg.h b/src/cmd/8g/gg.h
index c8d4ad613..81c265821 100644
--- a/src/cmd/8g/gg.h
+++ b/src/cmd/8g/gg.h
@@ -109,6 +109,8 @@ void	naddr(Node*, Addr*, int);
 void	cgen_aret(Node*, Node*);
 int	cgen_inline(Node*, Node*);
 Node*	ncon(uint32);
+void	mgen(Node*, Node*, Node*);
+void	mfree(Node*);
 
 /*
  * cgen64.c
diff --git a/src/cmd/8g/ggen.c b/src/cmd/8g/ggen.c
index f6fa7da0b..23177c240 100644
--- a/src/cmd/8g/ggen.c
+++ b/src/cmd/8g/ggen.c
@@ -843,9 +843,9 @@ int
 cgen_inline(Node *n, Node *res)
 {
 	Node nodes[5];
-	Node n1, n2, nres, nnode0, ntemp;
+	Node n1, n2, nres, ntemp;
 	vlong v;
-	int i, narg, bad;
+	int i, narg;
 
 	if(n->op != OCALLFUNC)
 		goto no;
@@ -950,47 +950,38 @@ slicearray:
 	return 1;
 
 sliceslice:
-	getargs(n->list, nodes, narg);
-
-	nres = *res;		// result
-	nnode0 = nodes[0];	// input slice
 	ntemp.op = OXXX;
-	if(!sleasy(res) || !sleasy(&nodes[0])) {
-		bad = 0;
-		if(res->ullman >= UINF)
-			bad = 1;
-		for(i=0; i<narg; i++) {
-			if(nodes[i].ullman >= UINF)
-				bad = 1;
-			if(nodes[i].op == OREGISTER)
-				regfree(&nodes[i]);
-		}
-
-		if(bad)
-			goto no;
-
+	if(!sleasy(n->list->n->right)) {
+		Node *n0;
+		
+		n0 = n->list->n->right;
 		tempname(&ntemp, res->type);
-		if(!sleasy(&nodes[0])) {
-			cgen(&nodes[0], &ntemp);
-			nnode0 = ntemp;
-		}
+		cgen(n0, &ntemp);
+		n->list->n->right = &ntemp;
+		getargs(n->list, nodes, narg);
+		n->list->n->right = n0;
+	} else
 		getargs(n->list, nodes, narg);
-		if(!sleasy(res))
-			nres = ntemp;
+
+	nres = *res;		// result
+	if(!sleasy(res)) {
+		if(ntemp.op == OXXX)
+			tempname(&ntemp, res->type);
+		nres = ntemp;
 	}
-	
+
 	if(narg == 3) {	// old[lb:]
 		// move width to where it would be for old[lb:hb]
 		nodes[3] = nodes[2];
 		nodes[2].op = OXXX;
 		
 		// if(lb[1] > old.nel[0]) goto throw;
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.xoffset += Array_nel;
 		cmpandthrow(&nodes[1], &n2);
 
 		// ret.nel = old.nel[0]-lb[1];
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.xoffset += Array_nel;
 	
 		regalloc(&n1, types[TUINT32], N);
@@ -1004,7 +995,7 @@ sliceslice:
 		regfree(&n1);
 	} else {	// old[lb:hb]
 		// if(hb[2] > old.cap[0]) goto throw;
-		n2 = nnode0;
+		n2 = nodes[0];
 		n2.xoffset += Array_cap;
 		cmpandthrow(&nodes[2], &n2);
 
@@ -1031,7 +1022,7 @@ sliceslice:
 	}
 
 	// ret.cap = old.cap[0]-lb[1]; (uses hb[2])
-	n2 = nnode0;
+	n2 = nodes[0];
 	n2.xoffset += Array_cap;
 
 	regalloc(&n1, types[TUINT32], &nodes[2]);
@@ -1045,7 +1036,7 @@ sliceslice:
 	regfree(&n1);
 
 	// ret.array = old.array[0]+lb[1]*width[3]; (uses lb[1])
-	n2 = nnode0;
+	n2 = nodes[0];
 	n2.xoffset += Array_array;
 
 	regalloc(&n1, types[tptr], &nodes[1]);
diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index 2cfca1985..eaf673f74 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -2476,6 +2476,9 @@ safeexpr(Node *n, NodeList **init)
 	Node *r;
 	Node *a;
 
+	if(n == N)
+		return N;
+
 	switch(n->op) {
 	case ONAME:
 	case OLITERAL:
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index fded073a3..ab4f946bd 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -900,8 +900,11 @@ walkexpr(Node **np, NodeList **init)
 
 	case OSLICE:
 		walkexpr(&n->left, init);
+		n->left = safeexpr(n->left, init);
 		walkexpr(&n->right->left, init);
+		n->right->left = safeexpr(n->right->left, init);
 		walkexpr(&n->right->right, init);
+		n->right->right = safeexpr(n->right->right, init);
 		// dynamic slice
 		// sliceslice(old []any, lb int, hb int, width int) (ary []any)
 		// sliceslice1(old []any, lb int, width int) (ary []any)
@@ -928,8 +931,11 @@ walkexpr(Node **np, NodeList **init)
 
 	case OSLICEARR:
 		walkexpr(&n->left, init);
+		n->left = safeexpr(n->left, init);
 		walkexpr(&n->right->left, init);
+		n->right->left = safeexpr(n->right->left, init);
 		walkexpr(&n->right->right, init);
+		n->right->right = safeexpr(n->right->right, init);
 		// static slice
 		// slicearray(old *any, nel int, lb int, hb int, width int) (ary []any)
 		t = n->type;
diff --git a/test/fixedbugs/bug261.go b/test/fixedbugs/bug261.go
new file mode 100644
index 000000000..8c3fda1e7
--- /dev/null
+++ b/test/fixedbugs/bug261.go
@@ -0,0 +1,23 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2010 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 main
+
+var n int
+
+func f() int {
+	n++
+	return n
+}
+
+func main() {
+	x := []int{0,1,2,3,4,5,6,7,8,9,10}
+	n = 5
+	y := x[f():f()]
+	if len(y) != 1 || y[0] != 6 {
+		println("BUG bug261", len(y), y[0])
+	}
+}