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Be more careful in applying pragma weak. Fixes pr14974. 

GCC applies a pragma weak to a decl if it matches the mangled name. We used
to apply if it matched the plain name.

This patch is a compromise: we apply the pragma only if it matches the name
and the decl has C language linkage.

llvm-svn: 176110
This commit is contained in:
Rafael Espindola 2013-02-26 19:13:56 +00:00
parent d2686ffa56
commit db77c4ae13
2 changed files with 41 additions and 2 deletions
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12
clang/lib/Sema/SemaDeclAttr.cpp
View File

@ -19,6 +19,7 @@
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Mangle.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
@ -5096,11 +5097,18 @@ void Sema::ProcessDeclAttributes(Scope *S, Decl *D, const Declarator &PD,
if (Inheritable) {
LoadExternalWeakUndeclaredIdentifiers();
if (!WeakUndeclaredIdentifiers.empty()) {
if (NamedDecl *ND = dyn_cast<NamedDecl>(D)) {
NamedDecl *ND = NULL;
if (VarDecl *VD = dyn_cast<VarDecl>(D))
if (VD->isExternC())
ND = VD;
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
if (FD->isExternC())
ND = FD;
if (ND) {
if (IdentifierInfo *Id = ND->getIdentifier()) {
llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator I
= WeakUndeclaredIdentifiers.find(Id);
if (I != WeakUndeclaredIdentifiers.end() && ND->hasLinkage()) {
if (I != WeakUndeclaredIdentifiers.end()) {
WeakInfo W = I->second;
DeclApplyPragmaWeak(S, ND, W);
WeakUndeclaredIdentifiers[Id] = W;

31
clang/test/CodeGenCXX/pragma-weak.cpp Normal file
View File

@ -0,0 +1,31 @@
// RUN: %clang_cc1 -emit-llvm %s -o - | FileCheck %s
#pragma weak zex
int zex;
// GCC produces a weak symbol for this because it matches mangled names.
// Different c++ ABIs may or may not mangle this, so we produce a strong
// symbol.
// CHECK: @zex = global i32
#pragma weak foo
struct S { void foo(); };
void S::foo() {}
// CHECK: define void @_ZN1S3fooEv(
#pragma weak zed
namespace bar { void zed() {} }
// CHECK: define void @_ZN3bar3zedEv(
#pragma weak bah
void bah() {}
// CHECK: define void @_Z3bahv(
#pragma weak baz
extern "C" void baz() {}
// CHECK: define weak void @baz(
#pragma weak _Z3baxv
void bax() {}
// GCC produces a weak symbol for this one, but it doesn't look like a good
// idea to expose the mangling to the pragma unless we really have to.
// CHECK: define void @_Z3baxv(