<div dir="ltr">This seems to have broken the GDB bot: <a href="http://lab.llvm.org:8011/builders/clang-x86_64-ubuntu-gdb-75/builds/10344">http://lab.llvm.org:8011/builders/clang-x86_64-ubuntu-gdb-75/builds/10344</a> ( <a href="http://lab.llvm.org:8011/builders/clang-x86_64-ubuntu-gdb-75/builds/10344/steps/gdb-75-check/logs/gdb.cp__destrprint.exp">http://lab.llvm.org:8011/builders/clang-x86_64-ubuntu-gdb-75/builds/10344/steps/gdb-75-check/logs/gdb.cp__destrprint.exp</a> )<br>
<br>I haven't looked too closely at the failure yet, but let me know if you need a hand understanding it or deciding if it's a true/false positive.<br><br>I suspect, while the optimization you've implemented is legitimate, it will reduce -O0 debuggability somewhat (as COMDAT/function deduplication tends to) - if it does so too severely we might want to enable it only in -O1 and above. (times like these it might be nice to have -Og)</div>
<div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Nov 8, 2013 at 2:59 PM, Rafael Espindola <span dir="ltr"><<a href="mailto:rafael.espindola@gmail.com" target="_blank">rafael.espindola@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: rafael<br>
Date: Fri Nov  8 16:59:46 2013<br>
New Revision: 194288<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=194288&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=194288&view=rev</a><br>
Log:<br>
If a linkonce_odr dtor/ctor is identical to another one, just rauw.<br>
<br>
Unlike an alias a rauw is always safe, so we don't need to avoid this<br>
optimization when the replacement is not know to be available in every TU.<br>
<br>
Modified:<br>
    cfe/trunk/lib/CodeGen/CGCXX.cpp<br>
    cfe/trunk/test/CodeGenCXX/ctor-dtor-alias.cpp<br>
    cfe/trunk/test/CodeGenCXX/destructors.cpp<br>
<br>
Modified: cfe/trunk/lib/CodeGen/CGCXX.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCXX.cpp?rev=194288&r1=194287&r2=194288&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCXX.cpp?rev=194288&r1=194287&r2=194288&view=diff</a><br>

==============================================================================<br>
--- cfe/trunk/lib/CodeGen/CGCXX.cpp (original)<br>
+++ cfe/trunk/lib/CodeGen/CGCXX.cpp Fri Nov  8 16:59:46 2013<br>
@@ -139,6 +139,13 @@ bool CodeGenModule::TryEmitDefinitionAsA<br>
   if (Ref->getType() != AliasType)<br>
     Aliasee = llvm::ConstantExpr::getBitCast(Ref, AliasType);<br>
<br>
+  // Instead of creating as alias to a linkonce_odr, replace all of the uses<br>
+  // of the aliassee.<br>
+  if (Linkage == llvm::GlobalValue::LinkOnceODRLinkage) {<br>
+    Replacements[MangledName] = Aliasee;<br>
+    return false;<br>
+  }<br>
+<br>
   // Don't create an alias to a linker weak symbol unless we know we can do<br>
   // that in every TU. This avoids producing different COMDATs in different<br>
   // TUs.<br>
@@ -146,12 +153,6 @@ bool CodeGenModule::TryEmitDefinitionAsA<br>
     if (!InEveryTU)<br>
       return true;<br>
<br>
-    // Instead of creating as alias to a linkonce_odr, replace all of the uses<br>
-    // of the aliassee.<br>
-    if (Linkage == llvm::GlobalValue::LinkOnceODRLinkage) {<br>
-      Replacements[MangledName] = Aliasee;<br>
-      return false;<br>
-    }<br>
     assert(Linkage == TargetLinkage);<br>
   }<br>
<br>
<br>
Modified: cfe/trunk/test/CodeGenCXX/ctor-dtor-alias.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/ctor-dtor-alias.cpp?rev=194288&r1=194287&r2=194288&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/ctor-dtor-alias.cpp?rev=194288&r1=194287&r2=194288&view=diff</a><br>

==============================================================================<br>
--- cfe/trunk/test/CodeGenCXX/ctor-dtor-alias.cpp (original)<br>
+++ cfe/trunk/test/CodeGenCXX/ctor-dtor-alias.cpp Fri Nov  8 16:59:46 2013<br>
@@ -45,10 +45,11 @@ B x;<br>
<br>
 namespace test4 {<br>
   // Test that we don't produce aliases from B to A. We cannot because we cannot<br>
-  // guarantee that they will be present in every TU.<br>
+  // guarantee that they will be present in every TU. Instead, we just call<br>
+  // A's destructor directly.<br>
<br>
-  // CHECK-DAG: define linkonce_odr void @_ZN5test41BD2Ev(<br>
   // CHECK-DAG: define linkonce_odr void @_ZN5test41AD2Ev(<br>
+  // CHECK-DAG: call i32 @__cxa_atexit{{.*}}_ZN5test41AD2Ev<br>
   struct A {<br>
     virtual ~A() {}<br>
   };<br>
<br>
Modified: cfe/trunk/test/CodeGenCXX/destructors.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/destructors.cpp?rev=194288&r1=194287&r2=194288&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/destructors.cpp?rev=194288&r1=194287&r2=194288&view=diff</a><br>

==============================================================================<br>
--- cfe/trunk/test/CodeGenCXX/destructors.cpp (original)<br>
+++ cfe/trunk/test/CodeGenCXX/destructors.cpp Fri Nov  8 16:59:46 2013<br>
@@ -45,7 +45,7 @@ namespace PR7526 {<br>
   allocator::~allocator() throw() { foo(); }<br>
<br>
   // CHECK-LABEL: define void @_ZN6PR75263fooEv()<br>
-  // CHECK: call void @_ZN6PR752617allocator_derivedD2Ev<br>
+  // CHECK: call void {{.*}} @_ZN6PR75269allocatorD2Ev<br>
<br>
   void foo() {<br>
     allocator_derived ad;<br>
<br>
<br>
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</blockquote></div><br></div>