cmd/ld: do not assume that only pe section names start with '.'

Our current pe object reader assumes that every symbol starting with
'.' is section. It appeared to be true, until now gcc 4.9.1 generates
some symbols with '.' at the front. Change that logic to check other
symbol fields in addition to checking for '.'. I am not an expert
here, but it seems reasonable to me.

Added test, but it is only good, if tested with gcc 4.9.1. Otherwise
the test PASSes regardless.

Fixes #8811.
Fixes #8856.

LGTM=jfrederich, iant, stephen.gutekanst
R=golang-codereviews, jfrederich, stephen.gutekanst, iant
CC=alex.brainman, golang-codereviews
https://golang.org/cl/152410043

diff --git a/misc/cgo/test/cgo_test.go b/misc/cgo/test/cgo_test.go
index 05deb4197c1d0af546f50dbc1b935f23d4c18c1c..3b289ba7b505392d29bb795e88e79a83e0d3ee55 100644 (file)
--- a/misc/cgo/test/cgo_test.go
+++ b/misc/cgo/test/cgo_test.go
@@ -59,6 +59,7 @@ func Test8092(t *testing.T)                  { test8092(t) }
 func Test7978(t *testing.T)                  { test7978(t) }
 func Test8694(t *testing.T)                  { test8694(t) }
 func Test8517(t *testing.T)                  { test8517(t) }
+func Test8811(t *testing.T)                  { test8811(t) }
 func TestReturnAfterGrow(t *testing.T)       { testReturnAfterGrow(t) }
 func TestReturnAfterGrowFromGo(t *testing.T) { testReturnAfterGrowFromGo(t) }
 

diff --git a/misc/cgo/test/issue8811.c b/misc/cgo/test/issue8811.c
new file mode 100644 (file)
index 0000000..584bb39
--- /dev/null
+++ b/misc/cgo/test/issue8811.c
@@ -0,0 +1,8 @@
+// Copyright 2014 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.
+
+int issue8811Initialized = 0;
+
+void issue8811Init() {
+}

diff --git a/misc/cgo/test/issue8811.go b/misc/cgo/test/issue8811.go
new file mode 100644 (file)
index 0000000..2e217d9
--- /dev/null
+++ b/misc/cgo/test/issue8811.go
@@ -0,0 +1,22 @@
+// Copyright 2014 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
+
+/*
+extern int issue8811Initialized;
+extern void issue8811Init();
+
+void issue8811Execute() {
+       if(!issue8811Initialized)
+               issue8811Init();
+}
+*/
+import "C"
+
+import "testing"
+
+func test8811(t *testing.T) {
+       C.issue8811Execute()
+}

diff --git a/src/cmd/ld/ldpe.c b/src/cmd/ld/ldpe.c
index 9257c243c94b342e15bc55d8f6a8c6dfbffdb4bb..4f5e51f2f1b5571a075478a6b4c0d8c58f3cf6ca 100644 (file)
--- a/src/cmd/ld/ldpe.c
+++ b/src/cmd/ld/ldpe.c
@@ -128,6 +128,7 @@ struct PeObj {
 };
 
 static int map(PeObj *obj, PeSect *sect);
+static int issect(PeSym *s);
 static int readsym(PeObj *obj, int i, PeSym **sym);
 
 void
@@ -318,8 +319,8 @@ ldpe(Biobuf *f, char *pkg, int64 len, char *pn)
                        // ld -r could generate multiple section symbols for the
                        // same section but with different values, we have to take
                        // that into account
-                       if (obj->pesym[symindex].name[0] == '.')
-                                       rp->add += obj->pesym[symindex].value;
+                       if(issect(&obj->pesym[symindex]))
+                               rp->add += obj->pesym[symindex].value;
                }
                qsort(r, rsect->sh.NumberOfRelocations, sizeof r[0], rbyoff);
                
@@ -327,12 +328,12 @@ ldpe(Biobuf *f, char *pkg, int64 len, char *pn)
                s->r = r;
                s->nr = rsect->sh.NumberOfRelocations;
        }
-       
+
        // enter sub-symbols into symbol table.
        for(i=0; i<obj->npesym; i++) {
                if(obj->pesym[i].name == 0)
                        continue;
-               if(obj->pesym[i].name[0] == '.') //skip section
+               if(issect(&obj->pesym[i]))
                        continue;
                if(obj->pesym[i].sectnum > 0) {
                        sect = &obj->sect[obj->pesym[i].sectnum-1];
@@ -430,6 +431,12 @@ map(PeObj *obj, PeSect *sect)
        return 0;
 }
 
+static int
+issect(PeSym *s)
+{
+       return s->sclass == IMAGE_SYM_CLASS_STATIC && s->type == 0 && s->name[0] == '.';
+}
+
 static int
 readsym(PeObj *obj, int i, PeSym **y)
 {
@@ -445,7 +452,7 @@ readsym(PeObj *obj, int i, PeSym **y)
        sym = &obj->pesym[i];
        *y = sym;
        
-       if(sym->name[0] == '.') // .section
+       if(issect(sym))
                name = obj->sect[sym->sectnum-1].sym->name;
        else {
                name = sym->name;