From: Shenghou Ma <minux.ma@gmail.com>
Date: Mon, 30 Jul 2012 22:44:48 +0000 (-0400)
Subject: cmd/cgo: use 1 as last entry for __cgodebug_data
X-Git-Tag: go1.1rc2~2736
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=dd62bb4753147ff832eb769af892054fb1562c7c;p=gostls13.git

cmd/cgo: use 1 as last entry for __cgodebug_data
        LLVM-based gcc will place all-zero data in a zero-filled
        section, but our debug/macho can't handle that.
        Fixes #3821.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6444049
---

diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index 93ecb3e3d0..18be64fc7c 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -508,7 +508,12 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
 			fmt.Fprintf(&b, "\t0,\n")
 		}
 	}
-	fmt.Fprintf(&b, "\t0\n")
+	// for the last entry, we can not use 0, otherwise
+	// in case all __cgodebug_data is zero initialized,
+	// LLVM-based gcc will place the it in the __DATA.__common
+	// zero-filled section (our debug/macho doesn't support
+	// this)
+	fmt.Fprintf(&b, "\t1\n")
 	fmt.Fprintf(&b, "};\n")
 
 	d, bo, debugData := p.gccDebug(b.Bytes())