From: Argyrios Kyrtzidis <akyrtzi@gmail.com>
Date: Wed, 13 Oct 2010 02:39:41 +0000 (+0000)
Subject: Embrace C++ ABI 5.2.6 and consider that template instantiations don't have key functi... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3bd5b6c3c2ad1d5a6f88cf21f627e8d4f03c4df4;p=clang

Embrace C++ ABI 5.2.6 and consider that template instantiations don't have key functions (same as GCC).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@116391 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp
index 0a095886ff..c5465a5dca 100644
--- a/lib/AST/RecordLayoutBuilder.cpp
+++ b/lib/AST/RecordLayoutBuilder.cpp
@@ -1562,6 +1562,13 @@ RecordLayoutBuilder::ComputeKeyFunction(const CXXRecordDecl *RD) {
   if (RD->isInAnonymousNamespace())
     return 0;
 
+  // Template instantiations don't have key functions,see Itanium C++ ABI 5.2.6.
+  // Same behavior as GCC.
+  TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind();
+  if (TSK == TSK_ImplicitInstantiation ||
+      TSK == TSK_ExplicitInstantiationDefinition)
+    return 0;
+
   for (CXXRecordDecl::method_iterator I = RD->method_begin(),
          E = RD->method_end(); I != E; ++I) {
     const CXXMethodDecl *MD = *I;
diff --git a/test/CodeGenCXX/template-instantiation.cpp b/test/CodeGenCXX/template-instantiation.cpp
index cb6c812316..47ff16b8a6 100644
--- a/test/CodeGenCXX/template-instantiation.cpp
+++ b/test/CodeGenCXX/template-instantiation.cpp
@@ -4,6 +4,9 @@
 // CHECK-NOT: _ZTVN5test315basic_fstreamXXIcEE
 // CHECK: @_ZTVN5test018stdio_sync_filebufIwEE = constant
 
+// CHECK-NOT: _ZTVN5test31SIiEE
+// CHECK-NOT: _ZTSN5test31SIiEE
+
 // CHECK: define linkonce_odr void @_ZN5test21CIiEC1Ev(
 // CHECK: define linkonce_odr void @_ZN5test21CIiE6foobarIdEEvT_(
 // CHECK: define available_externally void @_ZN5test21CIiE6zedbarEd(
@@ -75,3 +78,17 @@ namespace test3 {
   // (test at the top).
   template void basic_fstreamXX<char>::is_open() const;
 }
+
+namespace test3 {
+  template <typename T>
+  struct S  {
+      virtual void m();
+  };
+  
+  template<typename T>
+  void S<T>::m() { }
+
+  // Should not cause us to produce vtable because template instantiations
+  // don't have key functions.
+  template void S<int>::m();
+}