cmd/link: reject data size > 2 GB

We can't address more than this on amd64 anyway.

Fixes #9862.

Change-Id: Ifb1abae558e2e1ee2dc953a76995f3f08c60b1df
Reviewed-on: https://go-review.googlesource.com/11715
Reviewed-by: Austin Clements <austin@google.com>

diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 60b0be5ceb43142db316574eb693ee3e4d48f9d0..ab92b9430fe8a26597f6dc409b7be7d8296c705a 100644 (file)
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -1122,11 +1122,14 @@ func (p *GCProg) AddSym(s *LSym) {
 
 func growdatsize(datsizep *int64, s *LSym) {
        datsize := *datsizep
-       if s.Size < 0 {
-               Diag("negative size (datsize = %d, s->size = %d)", datsize, s.Size)
-       }
-       if datsize+s.Size < datsize {
-               Diag("symbol too large (datsize = %d, s->size = %d)", datsize, s.Size)
+       const cutoff int64 = 2e9 // 2 GB (or so; looks better in errors than 2^31)
+       switch {
+       case s.Size < 0:
+               Diag("%s: negative size (%d bytes)", s.Name, s.Size)
+       case s.Size > cutoff:
+               Diag("%s: symbol too large (%d bytes)", s.Name, s.Size)
+       case datsize <= cutoff && datsize+s.Size > cutoff:
+               Diag("%s: too much data (over %d bytes)", s.Name, cutoff)
        }
        *datsizep = datsize + s.Size
 }

diff --git a/test/fixedbugs/issue9862.go b/test/fixedbugs/issue9862.go
new file mode 100644 (file)
index 0000000..692a60d
--- /dev/null
+++ b/test/fixedbugs/issue9862.go
@@ -0,0 +1,15 @@
+// skip
+
+// 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 main
+
+var a [1<<31 - 1024]byte
+
+func main() {
+       if a[0] != 0 {
+               panic("bad array")
+       }
+}

diff --git a/test/fixedbugs/issue9862_run.go b/test/fixedbugs/issue9862_run.go
new file mode 100644 (file)
index 0000000..be22f40
--- /dev/null
+++ b/test/fixedbugs/issue9862_run.go
@@ -0,0 +1,27 @@
+// +build !nacl
+// run
+
+// 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.
+
+// Check for compile or link error.
+
+package main
+
+import (
+       "os/exec"
+       "strings"
+)
+
+func main() {
+       out, err := exec.Command("go", "run", "fixedbugs/issue9862.go").CombinedOutput()
+       outstr := string(out)
+       if err == nil {
+               println("go run issue9862.go succeeded, should have failed\n", outstr)
+               return
+       }
+       if !strings.Contains(outstr, "symbol too large") {
+               println("go run issue9862.go gave unexpected error; want symbol too large:\n", outstr)
+       }
+}