From cc1aa268ed3e30a66e118a21df2b9edf39034907 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Thu, 14 Aug 2014 20:30:52 +0000
Subject: [PATCH] [modules] Turn off a broken optimization: we need to pick up
 implicit special members from all redefinitions of a class that have them, in
 case the special member is defined in one module but only declared in
 another.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@215675 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Serialization/ASTReaderDecl.cpp  |  7 ++++--
 test/Modules/Inputs/templates-left.h |  6 +++++
 test/Modules/Inputs/templates-top.h  | 13 ++++++++++
 test/Modules/templates-2.mm          | 36 ++++++++++++++++++++++++++++
 4 files changed, 60 insertions(+), 2 deletions(-)
 create mode 100644 test/Modules/templates-2.mm

diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index dcb747fe8d..38837e2c06 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -1301,8 +1301,11 @@ void ASTDeclReader::MergeDefinitionData(
 
   // If the new definition has new special members, let the name lookup
   // code know that it needs to look in the new definition too.
-  if ((MergeDD.DeclaredSpecialMembers & ~DD.DeclaredSpecialMembers) &&
-      DD.Definition != MergeDD.Definition) {
+  //
+  // FIXME: We only need to do this if the merged definition declares members
+  // that this definition did not declare, or if it defines members that this
+  // definition did not define.
+  if (MergeDD.DeclaredSpecialMembers && DD.Definition != MergeDD.Definition) {
     Reader.MergedLookups[DD.Definition].push_back(MergeDD.Definition);
     DD.Definition->setHasExternalVisibleStorage();
   }
diff --git a/test/Modules/Inputs/templates-left.h b/test/Modules/Inputs/templates-left.h
index 2bd79be945..7ca5cc52a1 100644
--- a/test/Modules/Inputs/templates-left.h
+++ b/test/Modules/Inputs/templates-left.h
@@ -60,3 +60,9 @@ template<typename T> void testDelayUpdates(DelayUpdates<T> *p = 0) {}
 void outOfLineInlineUseLeftF(void (OutOfLineInline<int>::*)() = &OutOfLineInline<int>::f);
 void outOfLineInlineUseLeftG(void (OutOfLineInline<int>::*)() = &OutOfLineInline<int>::g);
 void outOfLineInlineUseLeftH(void (OutOfLineInline<int>::*)() = &OutOfLineInline<int>::h);
+
+namespace EmitDefaultedSpecialMembers {
+  inline void f() {
+    SmallString<256> SS;
+  };
+}
diff --git a/test/Modules/Inputs/templates-top.h b/test/Modules/Inputs/templates-top.h
index 1216266f34..b1e0548d41 100644
--- a/test/Modules/Inputs/templates-top.h
+++ b/test/Modules/Inputs/templates-top.h
@@ -40,3 +40,16 @@ template<typename T> struct OutOfLineInline {
 template<typename T> inline void OutOfLineInline<T>::f() {}
 template<typename T> inline void OutOfLineInline<T>::g() {}
 template<typename T> inline void OutOfLineInline<T>::h() {}
+
+namespace EmitDefaultedSpecialMembers {
+  template<typename T> struct SmallVectorImpl {
+    SmallVectorImpl() {}
+    ~SmallVectorImpl() {} // non-trivial dtor
+  };
+  template<typename T, unsigned N> struct SmallVector : SmallVectorImpl<T> {
+    // trivial dtor
+  };
+  template<unsigned N> struct SmallString : SmallVector<char, N> {
+    // trivial dtor
+  };
+}
diff --git a/test/Modules/templates-2.mm b/test/Modules/templates-2.mm
new file mode 100644
index 0000000000..b7ceafbbc5
--- /dev/null
+++ b/test/Modules/templates-2.mm
@@ -0,0 +1,36 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++11 -x objective-c++ -fmodules -fmodules-cache-path=%t -I %S/Inputs -verify %s -Wno-objc-root-class
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++11 -x objective-c++ -fmodules -fmodules-cache-path=%t -I %S/Inputs -emit-llvm %s -o - -Wno-objc-root-class | FileCheck %s
+// expected-no-diagnostics
+
+@import templates_top;
+
+struct TestEmitDefaultedSpecialMembers {
+  EmitDefaultedSpecialMembers::SmallVector<char, 256> V;
+};
+
+@import templates_left;
+
+void testEmitDefaultedSpecialMembers() {
+  EmitDefaultedSpecialMembers::SmallString<256> V;
+  // CHECK: call {{.*}} @_ZN27EmitDefaultedSpecialMembers11SmallStringILj256EEC1Ev(
+  // CHECK: call {{.*}} @_ZN27EmitDefaultedSpecialMembers11SmallStringILj256EED1Ev(
+}
+
+// CHECK-LABEL: define {{.*}} @_ZN27EmitDefaultedSpecialMembers11SmallStringILj256EEC1Ev(
+// CHECK: call {{.*}} @_ZN27EmitDefaultedSpecialMembers11SmallStringILj256EEC2Ev(
+
+// CHECK-LABEL: define {{.*}} @_ZN27EmitDefaultedSpecialMembers11SmallStringILj256EED1Ev(
+// CHECK: call {{.*}} @_ZN27EmitDefaultedSpecialMembers11SmallStringILj256EED2Ev(
+
+// CHECK-LABEL: define linkonce_odr void @_ZN27EmitDefaultedSpecialMembers11SmallStringILj256EED2Ev(
+// CHECK: call void @_ZN27EmitDefaultedSpecialMembers11SmallVectorIcLj256EED2Ev(
+// CHECK-LABEL: define linkonce_odr void @_ZN27EmitDefaultedSpecialMembers11SmallVectorIcLj256EED2Ev(
+// CHECK: call void @_ZN27EmitDefaultedSpecialMembers15SmallVectorImplIcED2Ev(
+// CHECK-LABEL: define linkonce_odr void @_ZN27EmitDefaultedSpecialMembers15SmallVectorImplIcED2Ev(
+
+// CHECK-LABEL: define linkonce_odr void @_ZN27EmitDefaultedSpecialMembers11SmallStringILj256EEC2Ev(
+// CHECK: call void @_ZN27EmitDefaultedSpecialMembers11SmallVectorIcLj256EEC2Ev(
+// CHECK-LABEL: define linkonce_odr void @_ZN27EmitDefaultedSpecialMembers11SmallVectorIcLj256EEC2Ev(
+// CHECK: call void @_ZN27EmitDefaultedSpecialMembers15SmallVectorImplIcEC2Ev(
+// CHECK-LABEL: define linkonce_odr void @_ZN27EmitDefaultedSpecialMembers15SmallVectorImplIcEC2Ev(
-- 
2.50.1