From a1cbab0992993189aa1d67fa6b1bcf47e5fe12c0 Mon Sep 17 00:00:00 2001
From: Joerg Sonnenberger <joerg@bec.de>
Date: Fri, 22 Nov 2013 21:34:35 +0000
Subject: [PATCH] Adjust r194296 to not apply the alias replacement for
externally available always-inline functions. This breaks libc++'s locale
implementation. Code generation for this case should be fixed, but this is a
stop gap fix for clang 3.4.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195501 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/CodeGen/CGCXX.cpp | 9 +++++++-
test/CodeGenCXX/ctor-dtor-alias.cpp | 32 +++++++++++++++++++++++++++++
2 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
index 22baa654084..cfb2d6291b8 100644
--- a/lib/CodeGen/CGCXX.cpp
+++ b/lib/CodeGen/CGCXX.cpp
@@ -140,7 +140,14 @@ bool CodeGenModule::TryEmitDefinitionAsAlias(GlobalDecl AliasDecl,
// Instead of creating as alias to a linkonce_odr, replace all of the uses
// of the aliassee.
- if (llvm::GlobalValue::isDiscardableIfUnused(Linkage)) {
+ if (llvm::GlobalValue::isDiscardableIfUnused(Linkage) &&
+ (TargetLinkage != llvm::GlobalValue::AvailableExternallyLinkage ||
+ !TargetDecl.getDecl()->hasAttr<AlwaysInlineAttr>())) {
+ // FIXME: An extern template instanciation will create functions with
+ // linkage "AvailableExternally". In libc++, some classes also define
+ // members with attribute "AlwaysInline" and expect no reference to
+ // be generated. It is desirable to reenable this optimisation after
+ // corresponding LLVM changes.
Replacements[MangledName] = Aliasee;
return false;
}
diff --git a/test/CodeGenCXX/ctor-dtor-alias.cpp b/test/CodeGenCXX/ctor-dtor-alias.cpp
index 6efd0bf9f87..235d1650dec 100644
--- a/test/CodeGenCXX/ctor-dtor-alias.cpp
+++ b/test/CodeGenCXX/ctor-dtor-alias.cpp
@@ -1,6 +1,9 @@
// RUN: %clang_cc1 %s -triple x86_64-linux -emit-llvm -o - -mconstructor-aliases -O1 -disable-llvm-optzns | FileCheck %s
// RUN: %clang_cc1 %s -triple x86_64-linux -emit-llvm -o - -mconstructor-aliases | FileCheck --check-prefix=NOOPT %s
+// RUN: %clang_cc1 -cc1 -triple x86_64--netbsd -emit-llvm \
+// RUN: -mconstructor-aliases -O2 %s -o - | FileCheck --check-prefix=CHECK-RAUW %s
+
namespace test1 {
// test that we don't produce an alias when the destructor is weak_odr. The
// reason to avoid it that another TU might have no explicit template
@@ -129,3 +132,32 @@ namespace test8 {
struct zed : public bar {};
zed foo;
}
+
+// CHECK-RAUW: @_ZTV1C = linkonce_odr unnamed_addr constant [4 x i8*] [{{[^@]*}}@_ZTI1C {{[^@]*}}@_ZN1CD2Ev {{[^@]*}}@_ZN1CD0Ev {{[^@]*}}]
+// r194296 replaced C::~C with B::~B without emitting the later.
+
+class A {
+public:
+ A(int);
+ virtual ~A();
+};
+
+template <class>
+class B : A {
+public:
+ B()
+ : A(0) {
+ }
+ __attribute__((always_inline)) ~B() {
+ }
+};
+
+extern template class B<char>;
+
+class C : B<char> {
+};
+
+void
+fn1() {
+ new C;
+}
--
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