Commit 1aa64b55 authored by Jeremy Faller's avatar Jeremy Faller

cmd/link: prefix Go syms with _ on darwin

RELNOTE=This change adds an underscore to all Go symbols in darwin, and
the behavior might be confusing to users of tools like "nm", etc.

Fixes #33808

Change-Id: I1849e6618c81215cb9bfa62b678f6f389cd009d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/196217
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarCherry Zhang <cherryyz@google.com>
parent baf7d953
// Copyright 2019 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 ld
import (
"internal/testenv"
"io/ioutil"
"os"
"runtime"
"strings"
"testing"
)
const prog = `
package main
import "log"
func main() {
log.Fatalf("HERE")
}
`
func TestIssue33808(t *testing.T) {
if runtime.GOOS != "darwin" {
return
}
testenv.MustHaveGoBuild(t)
testenv.MustHaveCGO(t)
dir, err := ioutil.TempDir("", "TestIssue33808")
if err != nil {
t.Fatalf("could not create directory: %v", err)
}
defer os.RemoveAll(dir)
f := gobuild(t, dir, prog, "-ldflags=-linkmode=external")
f.Close()
syms, err := f.Symbols()
if err != nil {
t.Fatalf("Error reading symbols: %v", err)
}
name := "log.Fatalf"
for _, sym := range syms {
if strings.Contains(sym.Name, name) {
return
}
}
t.Fatalf("Didn't find %v", name)
}
......@@ -869,6 +869,7 @@ func machosymtab(ctxt *Link) {
symtab.AddUint32(ctxt.Arch, uint32(symstr.Size))
export := machoShouldExport(ctxt, s)
isGoSymbol := strings.Contains(s.Extname(), ".")
// In normal buildmodes, only add _ to C symbols, as
// Go symbols have dot in the name.
......@@ -877,8 +878,8 @@ func machosymtab(ctxt *Link) {
// symbols like crosscall2 are in pclntab and end up
// pointing at the host binary, breaking unwinding.
// See Issue #18190.
cexport := !strings.Contains(s.Extname(), ".") && (ctxt.BuildMode != BuildModePlugin || onlycsymbol(s))
if cexport || export {
cexport := !isGoSymbol && (ctxt.BuildMode != BuildModePlugin || onlycsymbol(s))
if cexport || export || isGoSymbol {
symstr.AddUint8('_')
}
......
......@@ -473,7 +473,12 @@ func (f *File) parseSymtab(symdat, strtab, cmddat []byte, hdr *SymtabCmd, offset
if n.Name >= uint32(len(strtab)) {
return nil, &FormatError{offset, "invalid name in symbol table", n.Name}
}
sym.Name = cstring(strtab[n.Name:])
// We add "_" to Go symbols. Strip it here. See issue 33808.
name := cstring(strtab[n.Name:])
if strings.Contains(name, ".") && name[0] == '_' {
name = name[1:]
}
sym.Name = name
sym.Type = n.Type
sym.Sect = n.Sect
sym.Desc = n.Desc
......
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