From 9add729a1f537f05941d80a10818cf1562a7ea6b Mon Sep 17 00:00:00 2001
From: Shenghou Ma <minux.ma@gmail.com>
Date: Wed, 18 Sep 2013 22:27:25 -0400
Subject: [PATCH] cmd/ld: handle duplicate static symbols in COFF and Mach-O
 files. Fixes #5740.

R=iant, rsc, luisbebop
CC=gobot, golang-dev
https://golang.org/cl/10345046
---
 misc/cgo/test/issue5740.go | 15 +++++++++++++++
 misc/cgo/test/issue5740a.c |  9 +++++++++
 misc/cgo/test/issue5740b.c |  9 +++++++++
 src/cmd/ld/ldmacho.c       |  2 ++
 src/cmd/ld/ldpe.c          |  1 +
 5 files changed, 36 insertions(+)
 create mode 100644 misc/cgo/test/issue5740.go
 create mode 100644 misc/cgo/test/issue5740a.c
 create mode 100644 misc/cgo/test/issue5740b.c

diff --git a/misc/cgo/test/issue5740.go b/misc/cgo/test/issue5740.go
new file mode 100644
index 00000000000..25c86153fd5
--- /dev/null
+++ b/misc/cgo/test/issue5740.go
@@ -0,0 +1,15 @@
+// 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.
+
+package cgotest
+
+// int test5740a(void), test5740b(void);
+import "C"
+import "testing"
+
+func test5740(t *testing.T) {
+	if v := C.test5740a() + C.test5740b(); v != 5 {
+		t.Errorf("expected 5, got %v", v)
+	}
+}
diff --git a/misc/cgo/test/issue5740a.c b/misc/cgo/test/issue5740a.c
new file mode 100644
index 00000000000..25f18e2a455
--- /dev/null
+++ b/misc/cgo/test/issue5740a.c
@@ -0,0 +1,9 @@
+// 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.
+
+static int volatile val = 2;
+
+int test5740a() {
+	return val;
+}
diff --git a/misc/cgo/test/issue5740b.c b/misc/cgo/test/issue5740b.c
new file mode 100644
index 00000000000..22893f35bd8
--- /dev/null
+++ b/misc/cgo/test/issue5740b.c
@@ -0,0 +1,9 @@
+// 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.
+
+static int volatile val = 3;
+
+int test5740b() {
+	return val;
+}
diff --git a/src/cmd/ld/ldmacho.c b/src/cmd/ld/ldmacho.c
index 98a4eeac3ca..e0f5405f69c 100644
--- a/src/cmd/ld/ldmacho.c
+++ b/src/cmd/ld/ldmacho.c
@@ -611,6 +611,8 @@ ldmacho(Biobuf *f, char *pkg, int64 len, char *pn)
 		if(!(sym->type&N_EXT))
 			v = version;
 		s = lookup(name, v);
+		if(!(sym->type&N_EXT))
+			s->dupok = 1;
 		sym->sym = s;
 		if(sym->sectnum == 0)	// undefined
 			continue;
diff --git a/src/cmd/ld/ldpe.c b/src/cmd/ld/ldpe.c
index 033e522f277..6ed861d7f0c 100644
--- a/src/cmd/ld/ldpe.c
+++ b/src/cmd/ld/ldpe.c
@@ -469,6 +469,7 @@ readsym(PeObj *obj, int i, PeSym **y)
 		case IMAGE_SYM_CLASS_NULL:
 		case IMAGE_SYM_CLASS_STATIC:
 			s = lookup(name, version);
+			s->dupok = 1;
 			break;
 		default:
 			werrstr("%s: invalid symbol binding %d", sym->name, sym->sclass);