cmd/gc: fix overflow in array bounds calculation.

Fixes #5609.

R=golang-dev, remyoudompheng, r
CC=golang-dev
https://golang.org/cl/9757045

diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 12839009e332f749c45833fce4fc9ce6811125b3..550021de69054335914807bf004280a273898797 100644 (file)
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -420,12 +420,12 @@ reswitch:
                                goto error;
                        }
                        t->bound = mpgetfix(v.u.xval);
-                       if(t->bound < 0) {
-                               yyerror("array bound must be non-negative");
-                               goto error;
-                       } else if(doesoverflow(v, types[TINT])) {
+                       if(doesoverflow(v, types[TINT])) {
                                yyerror("array bound is too large"); 
                                goto error;
+                       } else if(t->bound < 0) {
+                               yyerror("array bound must be non-negative");
+                               goto error;
                        }
                }
                typecheck(&r, Etype);

diff --git a/test/fixedbugs/issue5609.go b/test/fixedbugs/issue5609.go
new file mode 100644 (file)
index 0000000..34619b3
--- /dev/null
+++ b/test/fixedbugs/issue5609.go
@@ -0,0 +1,13 @@
+// errorcheck
+
+// Copyright 2013 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.
+
+// issue 5609: overflow when calculating array size
+
+package pkg
+
+const Large uint64 = 18446744073709551615
+
+var foo [Large]uint64 // ERROR "array bound is too large"