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cmd/internal/obj: reject too large symbols

We never supported symbol larger than 2GB (issue #9862), so the
object file uses 32-bit for symbol sizes. Check and reject too
large symbol before truncating its size.

Fixes #42054.

Change-Id: I0d1d585ebdba9556f2fd3a97043bd4296d5cc9e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/263641
Trust: Cherry Zhang <cherryyz@google.com>
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
This commit is contained in:
Cherry Zhang 2020-10-19 10:40:24 -04:00
parent e2c420591c
commit c9c64886ef
3 changed files with 46 additions and 1 deletions

View File

@ -261,6 +261,10 @@ func (w *writer) StringTable() {
}
}
// cutoff is the maximum data section size permitted by the linker
// (see issue #9862).
const cutoff = int64(2e9) // 2 GB (or so; looks better in errors than 2^31)
func (w *writer) Sym(s *LSym) {
abi := uint16(s.ABI())
if s.Static() {
@ -325,6 +329,9 @@ func (w *writer) Sym(s *LSym) {
// don't bother setting align to 1.
}
}
if s.Size > cutoff {
w.ctxt.Diag("%s: symbol too large (%d bytes > %d bytes)", s.Name, s.Size, cutoff)
}
var o goobj.Sym
o.SetName(name, w.Writer)
o.SetABI(abi)

View File

@ -5,9 +5,16 @@
package obj
import (
"bytes"
"cmd/internal/goobj"
"cmd/internal/sys"
"internal/testenv"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"testing"
"unsafe"
)
var dummyArch = LinkArch{Arch: sys.ArchAMD64}
@ -85,3 +92,32 @@ func TestContentHash(t *testing.T) {
}
}
}
func TestSymbolTooLarge(t *testing.T) { // Issue 42054
testenv.MustHaveGoBuild(t)
if unsafe.Sizeof(uintptr(0)) < 8 {
t.Skip("skip on 32-bit architectures")
}
tmpdir, err := ioutil.TempDir("", "TestSymbolTooLarge")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(tmpdir)
src := filepath.Join(tmpdir, "p.go")
err = ioutil.WriteFile(src, []byte("package p; var x [1<<32]byte"), 0666)
if err != nil {
t.Fatalf("failed to write source file: %v\n", err)
}
obj := filepath.Join(tmpdir, "p.o")
cmd := exec.Command(testenv.GoToolPath(t), "tool", "compile", "-o", obj, src)
out, err := cmd.CombinedOutput()
if err == nil {
t.Fatalf("did not fail\noutput: %s", out)
}
const want = "symbol too large"
if !bytes.Contains(out, []byte(want)) {
t.Errorf("unexpected error message: want: %q, got: %s", want, out)
}
}

View File

@ -1,4 +1,4 @@
// compile
// skip
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
@ -7,6 +7,8 @@
// Issue 4348. After switch to 64-bit ints the compiler generates
// illegal instructions when using large array bounds or indexes.
// Skip. We reject symbols larger that 2GB (Issue #9862).
package main
// 1<<32 on a 64-bit machine, 1 otherwise.