<div dir="rtl"><div dir="ltr">The mangling is different when targeting MSVC ABI, see failure at</div><div dir="ltr"><br></div><div dir="ltr"><a href="http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/29889/steps/test_all/logs/Clang%20%3A%3A%20CodeGenCXX__alias-available-externally.cpp">http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/29889/steps/test_all/logs/Clang%20%3A%3A%20CodeGenCXX__alias-available-externally.cpp</a><br></div><div dir="ltr"><br></div><div dir="ltr">maybe -triple x86_64-pc-linux ?</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div dir="ltr">2016-10-02 6:06 GMT+03:00 Aditya Kumar via cfe-commits <span dir="ltr"><<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>></span>:</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: hiraditya<br>
Date: Sat Oct 1 22:06:36 2016<br>
New Revision: 283063<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=283063&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project?rev=283063&view=rev</a><br>
Log:<br>
Alias must point to a definition<br>
<br>
Reapplying the patch after modifying the test case.<br>
<br>
Inlining the destructor caused the compiler to generate bad IR which failed the Verifier in the backend.<br>
<a href="https://llvm.org/bugs/show_bug.cgi?id=30341" rel="noreferrer" target="_blank">https://llvm.org/bugs/show_<wbr>bug.cgi?id=30341</a><br>
<br>
This patch disables alias to available_externally definitions.<br>
<br>
Reviewers: eugenis, rsmith<br>
<br>
Differential Revision: <a href="https://reviews.llvm.org/D24682" rel="noreferrer" target="_blank">https://reviews.llvm.org/<wbr>D24682</a><br>
<br>
Added:<br>
cfe/trunk/test/CodeGenCXX/<wbr>alias-available-externally.cpp<br>
Modified:<br>
cfe/trunk/lib/CodeGen/CGCXX.<wbr>cpp<br>
<br>
Modified: cfe/trunk/lib/CodeGen/CGCXX.<wbr>cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCXX.cpp?rev=283063&r1=283062&r2=283063&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/cfe/trunk/lib/CodeGen/<wbr>CGCXX.cpp?rev=283063&r1=<wbr>283062&r2=283063&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- cfe/trunk/lib/CodeGen/CGCXX.<wbr>cpp (original)<br>
+++ cfe/trunk/lib/CodeGen/CGCXX.<wbr>cpp Sat Oct 1 22:06:36 2016<br>
@@ -134,6 +134,11 @@ bool CodeGenModule::<wbr>TryEmitDefinitionAsA<br>
llvm::GlobalValue::<wbr>LinkageTypes TargetLinkage =<br>
getFunctionLinkage(TargetDecl)<wbr>;<br>
<br>
+ // available_externally definitions aren't real definitions, so we cannot<br>
+ // create an alias to one.<br>
+ if (TargetLinkage == llvm::GlobalValue::<wbr>AvailableExternallyLinkage)<br>
+ return true;<br>
+<br>
// Check if we have it already.<br>
StringRef MangledName = getMangledName(AliasDecl);<br>
llvm::GlobalValue *Entry = GetGlobalValue(MangledName);<br>
@@ -156,14 +161,7 @@ bool CodeGenModule::<wbr>TryEmitDefinitionAsA<br>
<br>
// Instead of creating as alias to a linkonce_odr, replace all of the uses<br>
// of the aliasee.<br>
- if (llvm::GlobalValue::<wbr>isDiscardableIfUnused(Linkage) &&<br>
- (TargetLinkage != llvm::GlobalValue::<wbr>AvailableExternallyLinkage ||<br>
- !TargetDecl.getDecl()-><wbr>hasAttr<AlwaysInlineAttr>())) {<br>
- // FIXME: An extern template instantiation will create functions with<br>
- // linkage "AvailableExternally". In libc++, some classes also define<br>
- // members with attribute "AlwaysInline" and expect no reference to<br>
- // be generated. It is desirable to reenable this optimisation after<br>
- // corresponding LLVM changes.<br>
+ if (llvm::GlobalValue::<wbr>isDiscardableIfUnused(Linkage)<wbr>) {<br>
addReplacement(MangledName, Aliasee);<br>
return false;<br>
}<br>
<br>
Added: cfe/trunk/test/CodeGenCXX/<wbr>alias-available-externally.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/alias-available-externally.cpp?rev=283063&view=auto" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/cfe/trunk/test/<wbr>CodeGenCXX/alias-available-<wbr>externally.cpp?rev=283063&<wbr>view=auto</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- cfe/trunk/test/CodeGenCXX/<wbr>alias-available-externally.cpp (added)<br>
+++ cfe/trunk/test/CodeGenCXX/<wbr>alias-available-externally.cpp Sat Oct 1 22:06:36 2016<br>
@@ -0,0 +1,20 @@<br>
+// RUN: %clang_cc1 -O1 -std=c++11 -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s<br>
+// Clang should not generate alias to available_externally definitions.<br>
+// Check that the destructor of Foo is defined.<br>
+// The destructors have different return type for different targets.<br>
+// CHECK: define linkonce_odr {{.*}} @_ZN3FooD2Ev<br>
+template <class CharT><br>
+struct String {<br>
+ String() {}<br>
+ ~String();<br>
+};<br>
+<br>
+template <class CharT><br>
+inline __attribute__((visibility("<wbr>hidden"), always_inline))<br>
+String<CharT>::~String() {}<br>
+<br>
+extern template struct String<char>;<br>
+<br>
+struct Foo : public String<char> { Foo() { String<char> s; } };<br>
+<br>
+Foo f;<br>
<br>
<br>
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</blockquote></div><br></div>