Revert r260388 "[MS ABI] Never reference dllimport'd vtables"

This caused the compiler to fail with "invalid linkage type
for global declaration" (PR26569).

llvm-svn: 260449

diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 930cf00..0634319 100644 (file)
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -2599,10 +2599,7 @@ void MicrosoftMangleContextImpl::mangleCXXVFTable(
   // NOTE: <cvr-qualifiers> here is always 'B' (const). <storage-class>
   // is always '6' for vftables.
   MicrosoftCXXNameMangler Mangler(*this, Out);
-  if (Derived->hasAttr<DLLImportAttr>())
-    Mangler.getStream() << "\01??_S";
-  else
-    Mangler.getStream() << "\01??_7";
+  Mangler.getStream() << "\01??_7";
   Mangler.mangleName(Derived);
   Mangler.getStream() << "6B"; // '6' for vftable, 'B' for const.
   for (const CXXRecordDecl *RD : BasePath)

diff --git a/clang/lib/AST/VTableBuilder.cpp b/clang/lib/AST/VTableBuilder.cpp
index b728b27..bae0186 100644 (file)
--- a/clang/lib/AST/VTableBuilder.cpp
+++ b/clang/lib/AST/VTableBuilder.cpp
@@ -2548,6 +2548,7 @@ public:
     // Only include the RTTI component if we know that we will provide a
     // definition of the vftable.
     HasRTTIComponent = Context.getLangOpts().RTTIData &&
+                       !MostDerivedClass->hasAttr<DLLImportAttr>() &&
                        MostDerivedClass->getTemplateSpecializationKind() !=
                            TSK_ExplicitInstantiationDeclaration;
 

diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index 2567aa9..2870a91 100644 (file)
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -1673,16 +1673,7 @@ llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
   SmallString<256> VFTableName;
   mangleVFTableName(getMangleContext(), RD, VFPtr, VFTableName);
 
-  // Classes marked __declspec(dllimport) need vftables generated on the
-  // import-side in order to support features like constexpr.  No other
-  // translation unit relies on the emission of the local vftable, translation
-  // units are expected to generate them as needed.
-  //
-  // Because of this unique behavior, we maintain this logic here instead of
-  // getVTableLinkage.
-  llvm::GlobalValue::LinkageTypes VFTableLinkage =
-      RD->hasAttr<DLLImportAttr>() ? llvm::GlobalValue::LinkOnceODRLinkage
-                                   : CGM.getVTableLinkage(RD);
+  llvm::GlobalValue::LinkageTypes VFTableLinkage = CGM.getVTableLinkage(RD);
   bool VFTableComesFromAnotherTU =
       llvm::GlobalValue::isAvailableExternallyLinkage(VFTableLinkage) ||
       llvm::GlobalValue::isExternalLinkage(VFTableLinkage);
@@ -1755,7 +1746,9 @@ llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
   if (C)
     VTable->setComdat(C);
 
-  if (RD->hasAttr<DLLExportAttr>())
+  if (RD->hasAttr<DLLImportAttr>())
+    VFTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
+  else if (RD->hasAttr<DLLExportAttr>())
     VFTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
 
   VFTablesMap[ID] = VFTable;

diff --git a/clang/test/CodeGenCXX/dllimport-rtti.cpp b/clang/test/CodeGenCXX/dllimport-rtti.cpp
index 4baee50..071ce27 100644 (file)
--- a/clang/test/CodeGenCXX/dllimport-rtti.cpp
+++ b/clang/test/CodeGenCXX/dllimport-rtti.cpp
@@ -4,8 +4,7 @@
 struct __declspec(dllimport) S {
   virtual void f() {}
 } s;
-// MSVC: [[VF_S:.*]] = private unnamed_addr constant [2 x i8*]
-// MSVC-DAG: @"\01??_SS@@6B@" = unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* [[VF_S]], i32 0, i32 1)
+// MSVC-DAG: @"\01??_7S@@6B@" = available_externally dllimport
 // MSVC-DAG: @"\01??_R0?AUS@@@8" = linkonce_odr
 // MSVC-DAG: @"\01??_R1A@?0A@EA@S@@8" = linkonce_odr
 // MSVC-DAG: @"\01??_R2S@@8" = linkonce_odr

diff --git a/clang/test/CodeGenCXX/dllimport.cpp b/clang/test/CodeGenCXX/dllimport.cpp
index e336bfb..b9c850b 100644 (file)
--- a/clang/test/CodeGenCXX/dllimport.cpp
+++ b/clang/test/CodeGenCXX/dllimport.cpp
@@ -614,7 +614,7 @@ USEMEMFUNC(V, foo)
 struct __declspec(dllimport) W { virtual void foo() {} };
 USECLASS(W)
 // vftable:
-// MO1-DAG: @"\01??_SW@@6B@" = linkonce_odr unnamed_addr constant [1 x i8*] [i8* bitcast (void (%struct.W*)* @"\01?foo@W@@UAEXXZ" to i8*)]
+// MO1-DAG: @"\01??_7W@@6B@" = available_externally dllimport unnamed_addr constant [1 x i8*] [i8* bitcast (void (%struct.W*)* @"\01?foo@W@@UAEXXZ" to i8*)]
 // GO1-DAG: @_ZTV1W = available_externally dllimport unnamed_addr constant [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.W*)* @_ZN1W3fooEv to i8*)]
 
 struct __declspec(dllimport) KeyFuncClass {

diff --git a/clang/test/CodeGenCXX/microsoft-abi-vftables.cpp b/clang/test/CodeGenCXX/microsoft-abi-vftables.cpp
index d94c9c1..f32bff0 100644 (file)
--- a/clang/test/CodeGenCXX/microsoft-abi-vftables.cpp
+++ b/clang/test/CodeGenCXX/microsoft-abi-vftables.cpp
@@ -4,6 +4,8 @@
 // RTTI-DAG: $"\01??_7S@@6B@" = comdat largest
 // RTTI-DAG: $"\01??_7V@@6B@" = comdat largest
 
+// RTTI-NOT: @"\01??_R4U@@6B@"
+
 struct S {
   virtual ~S();
 } s;
@@ -17,10 +19,9 @@ struct __declspec(dllimport) U {
   virtual ~U();
 } u;
 
-// RTTI-DAG: [[VTABLE_U:@.*]] = private unnamed_addr constant [2 x i8*] [i8* bitcast ({{.*}} @"\01??_R4U@@6B@" to i8*), i8* bitcast ({{.*}} @"\01??_GU@@UAEPAXI@Z" to i8*)]
-// RTTI-DAG: @"\01??_SU@@6B@" = unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* [[VTABLE_U]], i32 0, i32 1)
+// RTTI-DAG: @"\01??_7U@@6B@" = available_externally dllimport unnamed_addr constant [1 x i8*] [i8* bitcast ({{.*}} @"\01??_GU@@UAEPAXI@Z" to i8*)]
 
-// NO-RTTI-DAG: @"\01??_SU@@6B@" = linkonce_odr unnamed_addr constant [1 x i8*] [i8* bitcast ({{.*}} @"\01??_GU@@UAEPAXI@Z" to i8*)]
+// NO-RTTI-DAG: @"\01??_7U@@6B@" = available_externally dllimport unnamed_addr constant [1 x i8*] [i8* bitcast ({{.*}} @"\01??_GU@@UAEPAXI@Z" to i8*)]
 
 struct __declspec(dllexport) V {
   virtual ~V();