8g: bug272

Fixes #589.

R=ken2
CC=golang-dev
https://golang.org/cl/1043042

diff --git a/src/cmd/8g/cgen.c b/src/cmd/8g/cgen.c
index d7a5ab33ab22948ce2b63886b997aa3d20222689..9ebbc4b4f75d96d3082c333fec3e504cd3a6744d 100644 (file)
--- a/src/cmd/8g/cgen.c
+++ b/src/cmd/8g/cgen.c
@@ -430,6 +430,33 @@ flt2:      // binary
        return;
 }
 
+/*
+ * generate array index into res.
+ * n might be any size; res is 32-bit.
+ * returns Prog* to patch to panic call.
+ */
+Prog*
+cgenindex(Node *n, Node *res)
+{
+       Node tmp, lo, hi, zero;
+       Prog *p;
+
+       if(!is64(n->type)) {
+               cgen(n, res);
+               return nil;
+       }
+
+       tempname(&tmp, types[TINT64]);
+       cgen(n, &tmp);
+       split64(&tmp, &lo, &hi);
+       gmove(&lo, res);
+       if(debug['B'])
+               return nil;
+       nodconst(&zero, types[TINT32], 0);
+       gins(ACMPL, &hi, &zero);
+       return gbranch(AJNE, T);
+}
+               
 /*
  * address gen
  *     res = &n;
@@ -442,7 +469,7 @@ agen(Node *n, Node *res)
        Type *t;
        uint32 w;
        uint64 v;
-       Prog *p1;
+       Prog *p1, *p2;
 
        if(debug['g']) {
                dump("\nagen-res", res);
@@ -489,20 +516,20 @@ agen(Node *n, Node *res)
                break;
 
        case OINDEX:
-               // TODO(rsc): uint64 indices
+               p2 = nil;  // to be patched to panicindex.
                w = n->type->width;
                if(nr->addable) {
                        agenr(nl, &n3, res);
                        if(!isconst(nr, CTINT)) {
                                tempname(&tmp, types[TINT32]);
-                               cgen(nr, &tmp);
+                               p2 = cgenindex(nr, &tmp);
                                regalloc(&n1, tmp.type, N);
                                gmove(&tmp, &n1);
                        }
                } else if(nl->addable) {
                        if(!isconst(nr, CTINT)) {
                                tempname(&tmp, types[TINT32]);
-                               cgen(nr, &tmp);
+                               p2 = cgenindex(nr, &tmp);
                                regalloc(&n1, tmp.type, N);
                                gmove(&tmp, &n1);
                        }
@@ -510,7 +537,7 @@ agen(Node *n, Node *res)
                        agen(nl, &n3);
                } else {
                        tempname(&tmp, types[TINT32]);
-                       cgen(nr, &tmp);
+                       p2 = cgenindex(nr, &tmp);
                        nr = &tmp;
                        agenr(nl, &n3, res);
                        regalloc(&n1, tmp.type, N);
@@ -575,12 +602,7 @@ agen(Node *n, Node *res)
                        break;
                }
 
-               // type of the index
-               t = types[TUINT32];
-               if(issigned[n1.type->etype])
-                       t = types[TINT32];
-
-               regalloc(&n2, t, &n1);                  // i
+               regalloc(&n2, types[TINT32], &n1);                      // i
                gmove(&n1, &n2);
                regfree(&n1);
 
@@ -595,6 +617,8 @@ agen(Node *n, Node *res)
                                nodconst(&n1, types[TUINT32], nl->type->bound);
                        gins(optoas(OCMP, types[TUINT32]), &n2, &n1);
                        p1 = gbranch(optoas(OLT, types[TUINT32]), T);
+                       if(p2)
+                               patch(p2, pc);
                        ginscall(panicindex, 0);
                        patch(p1, pc);
                }
@@ -613,8 +637,8 @@ agen(Node *n, Node *res)
                        p1->from.index = p1->from.type;
                        p1->from.type = p1->to.type + D_INDIR;
                } else {
-                       nodconst(&n1, t, w);
-                       gins(optoas(OMUL, t), &n1, &n2);
+                       nodconst(&n1, types[TUINT32], w);
+                       gins(optoas(OMUL, types[TUINT32]), &n1, &n2);
                        gins(optoas(OADD, types[tptr]), &n2, &n3);
                        gmove(&n3, res);
                }

diff --git a/test/fixedbugs/bug272.go b/test/fixedbugs/bug272.go
new file mode 100644 (file)
index 0000000..3b7c466
--- /dev/null
+++ b/test/fixedbugs/bug272.go
@@ -0,0 +1,25 @@
+// $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.
+
+// http://code.google.com/p/go/issues/detail?id=589
+
+package main
+
+func main() {  
+       n := int64(100)
+       x := make([]int, n)
+       x[99] = 234;    
+       z := x[n-1]
+       if z != 234 {
+               println("BUG")
+       }
+       n |= 1<<32
+       defer func() {
+               recover()
+       }()
+       z = x[n-1]
+       println("BUG2")
+}