Vector deleting destructors

clang/include/clang/AST/VTableBuilder.h

@@ -150,7 +150,7 @@ class VTableComponent {
 
   bool isRTTIKind() const { return isRTTIKind(getKind()); }
 
-  GlobalDecl getGlobalDecl() const {
+  GlobalDecl getGlobalDecl(bool isMSVC) const {
     assert(isUsedFunctionPointerKind() &&
            "GlobalDecl can be created only from virtual function");
 
@@ -161,7 +161,8 @@ class VTableComponent {
     case CK_CompleteDtorPointer:
       return GlobalDecl(DtorDecl, CXXDtorType::Dtor_Complete);
     case CK_DeletingDtorPointer:
-      return GlobalDecl(DtorDecl, CXXDtorType::Dtor_Deleting);
+      return GlobalDecl(DtorDecl, (isMSVC) ? CXXDtorType::Dtor_VectorDeleting
+                                           : CXXDtorType::Dtor_Deleting);
     case CK_VCallOffset:
     case CK_VBaseOffset:
     case CK_OffsetToTop:

clang/include/clang/Basic/ABI.h

@@ -31,10 +31,11 @@ enum CXXCtorType {
 
 /// C++ destructor types.
 enum CXXDtorType {
-    Dtor_Deleting, ///< Deleting dtor
-    Dtor_Complete, ///< Complete object dtor
-    Dtor_Base,     ///< Base object dtor
-    Dtor_Comdat    ///< The COMDAT used for dtors
+  Dtor_Deleting,      ///< Deleting dtor
+  Dtor_Complete,      ///< Complete object dtor
+  Dtor_Base,          ///< Base object dtor
+  Dtor_Comdat,        ///< The COMDAT used for dtors
+  Dtor_VectorDeleting ///< Vector deleting dtor
 };
 
 } // end namespace clang

clang/lib/AST/ItaniumMangle.cpp

@@ -6001,6 +6001,8 @@ void CXXNameMangler::mangleCXXDtorType(CXXDtorType T) {
   case Dtor_Comdat:
     Out << "D5";
     break;
+  case Dtor_VectorDeleting:
+    llvm_unreachable("Itanium ABI does not use vector deleting dtors");
   }
 }
 

clang/lib/AST/MicrosoftMangle.cpp

@@ -1484,8 +1484,7 @@ void MicrosoftCXXNameMangler::mangleCXXDtorType(CXXDtorType T) {
   // <operator-name> ::= ?_G # scalar deleting destructor
   case Dtor_Deleting: Out << "?_G"; return;
   // <operator-name> ::= ?_E # vector deleting destructor
-  // FIXME: Add a vector deleting dtor type.  It goes in the vtable, so we need
-  // it.
+  case Dtor_VectorDeleting: Out << "?_E"; return;
   case Dtor_Comdat:
     llvm_unreachable("not expecting a COMDAT");
   }
@@ -2886,9 +2885,12 @@ void MicrosoftCXXNameMangler::mangleFunctionType(const FunctionType *T,
   //               ::= @ # structors (they have no declared return type)
   if (IsStructor) {
     if (isa<CXXDestructorDecl>(D) && isStructorDecl(D)) {
-      // The scalar deleting destructor takes an extra int argument which is not
+      // The deleting destructors take an extra argument of type int that indicates
+      // whether the storage for the object should be deleted and whether a single
+      // object or an array of objects is being destroyed. This extra argument is not
       // reflected in the AST.
-      if (StructorType == Dtor_Deleting) {
+      if (StructorType == Dtor_Deleting ||
+          StructorType == Dtor_VectorDeleting) {
         Out << (PointersAre64Bit ? "PEAXI@Z" : "PAXI@Z");
         return;
       }
@@ -3861,10 +3863,10 @@ void MicrosoftMangleContextImpl::mangleCXXDtorThunk(const CXXDestructorDecl *DD,
                                                     const ThunkInfo &Thunk,
                                                     bool /*ElideOverrideInfo*/,
                                                     raw_ostream &Out) {
-  // FIXME: Actually, the dtor thunk should be emitted for vector deleting
-  // dtors rather than scalar deleting dtors. Just use the vector deleting dtor
-  // mangling manually until we support both deleting dtor types.
-  assert(Type == Dtor_Deleting);
+  // The dtor thunk should use vector deleting dtor mangling, however as an
+  // optimization we may end up emitting only scalar deleting dtor body, so just
+  // use the vector deleting dtor mangling manually.
+  assert(Type == Dtor_Deleting || Type == Dtor_VectorDeleting);
   msvc_hashing_ostream MHO(Out);
   MicrosoftCXXNameMangler Mangler(*this, MHO, DD, Type);
   Mangler.getStream() << "??_E";

clang/lib/AST/VTableBuilder.cpp

@@ -1341,7 +1341,6 @@ void ItaniumVTableBuilder::AddMethod(const CXXMethodDecl *MD,
   if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
     assert(ReturnAdjustment.isEmpty() &&
            "Destructor can't have return adjustment!");
-
     // Add both the complete destructor and the deleting destructor.
     Components.push_back(VTableComponent::MakeCompleteDtor(DD));
     Components.push_back(VTableComponent::MakeDeletingDtor(DD));
@@ -1733,8 +1732,8 @@ void ItaniumVTableBuilder::LayoutPrimaryAndSecondaryVTables(
       const CXXMethodDecl *MD = I.first;
       const MethodInfo &MI = I.second;
       if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
-        MethodVTableIndices[GlobalDecl(DD, Dtor_Complete)]
-            = MI.VTableIndex - AddressPoint;
+        MethodVTableIndices[GlobalDecl(DD, Dtor_Complete)] =
+            MI.VTableIndex - AddressPoint;
         MethodVTableIndices[GlobalDecl(DD, Dtor_Deleting)]
             = MI.VTableIndex + 1 - AddressPoint;
       } else {
@@ -2655,7 +2654,10 @@ class VFTableBuilder {
       MethodVFTableLocation Loc(MI.VBTableIndex, WhichVFPtr.getVBaseWithVPtr(),
                                 WhichVFPtr.NonVirtualOffset, MI.VFTableIndex);
       if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
-        MethodVFTableLocations[GlobalDecl(DD, Dtor_Deleting)] = Loc;
+        if (!Context.getTargetInfo().getCXXABI().isMicrosoft())
+          MethodVFTableLocations[GlobalDecl(DD, Dtor_Deleting)] = Loc;
+        else
+          MethodVFTableLocations[GlobalDecl(DD, Dtor_VectorDeleting)] = Loc;
       } else {
         MethodVFTableLocations[MD] = Loc;
       }
@@ -3285,7 +3287,10 @@ void VFTableBuilder::dumpLayout(raw_ostream &Out) {
       const CXXDestructorDecl *DD = Component.getDestructorDecl();
 
       DD->printQualifiedName(Out);
-      Out << "() [scalar deleting]";
+      if (Context.getTargetInfo().getCXXABI().isMicrosoft())
+        Out << "() [vector deleting]";
+      else
+        Out << "() [scalar deleting]";
 
       if (DD->isPureVirtual())
         Out << " [pure]";
@@ -3756,7 +3761,7 @@ void MicrosoftVTableContext::dumpMethodLocations(
         PredefinedIdentKind::PrettyFunctionNoVirtual, MD);
 
     if (isa<CXXDestructorDecl>(MD)) {
-      IndicesMap[I.second] = MethodName + " [scalar deleting]";
+      IndicesMap[I.second] = MethodName + " [vector deleting]";
     } else {
       IndicesMap[I.second] = MethodName;
     }
@@ -3873,7 +3878,7 @@ MicrosoftVTableContext::getMethodVFTableLocation(GlobalDecl GD) {
   assert(hasVtableSlot(cast<CXXMethodDecl>(GD.getDecl())) &&
          "Only use this method for virtual methods or dtors");
   if (isa<CXXDestructorDecl>(GD.getDecl()))
-    assert(GD.getDtorType() == Dtor_Deleting);
+    assert(GD.getDtorType() == Dtor_VectorDeleting);
 
   GD = GD.getCanonicalDecl();
 

clang/lib/CodeGen/CGCXX.cpp

@@ -175,7 +175,6 @@ bool CodeGenModule::TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D) {
   // requires explicit comdat support in the IL.
   if (llvm::GlobalValue::isWeakForLinker(TargetLinkage))
     return true;
-
   // Create the alias with no name.
   auto *Alias = llvm::GlobalAlias::create(AliasValueType, 0, Linkage, "",
                                           Aliasee, &getModule());
@@ -201,6 +200,45 @@ bool CodeGenModule::TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D) {
   return false;
 }
 
+/// Emit a definition as a global alias for another definition, unconditionally.
+/// Use this function with care as it can produce invalid aliases.  Generally
+/// this function should be used only where there is an ABI requirement to emit
+/// an alias.
+void CodeGenModule::EmitDefinitionAsAlias(GlobalDecl AliasDecl,
+                                          GlobalDecl TargetDecl) {
+
+  llvm::Type *AliasValueType = getTypes().GetFunctionType(AliasDecl);
+
+  StringRef MangledName = getMangledName(AliasDecl);
+  llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
+  if (Entry && !Entry->isDeclaration())
+    return;
+  auto *Aliasee = cast<llvm::GlobalValue>(GetAddrOfGlobal(TargetDecl));
+
+  // Determine the linkage type for the alias.
+  llvm::GlobalValue::LinkageTypes Linkage = getFunctionLinkage(AliasDecl);
+
+  // Create the alias with no name.
+  auto *Alias = llvm::GlobalAlias::create(AliasValueType, 0, Linkage, "",
+                                          Aliasee, &getModule());
+  // Destructors are always unnamed_addr.
+  Alias->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
+
+  if (Entry) {
+    assert(Entry->getValueType() == AliasValueType &&
+           Entry->getAddressSpace() == Alias->getAddressSpace() &&
+           "declaration exists with different type");
+    Alias->takeName(Entry);
+    Entry->replaceAllUsesWith(Alias);
+    Entry->eraseFromParent();
+  } else {
+    Alias->setName(MangledName);
+  }
+
+  // Set any additional necessary attributes for the alias.
+  SetCommonAttributes(AliasDecl, Alias);
+}
+
 llvm::Function *CodeGenModule::codegenCXXStructor(GlobalDecl GD) {
   const CGFunctionInfo &FnInfo = getTypes().arrangeCXXStructorDeclaration(GD);
   auto *Fn = cast<llvm::Function>(

clang/lib/CodeGen/CGCXXABI.cpp

@@ -273,6 +273,20 @@ void CGCXXABI::ReadArrayCookie(CodeGenFunction &CGF, Address ptr,
   numElements = readArrayCookieImpl(CGF, allocAddr, cookieSize);
 }
 
+void CGCXXABI::ReadArrayCookie(CodeGenFunction &CGF, Address ptr,
+                               QualType eltTy, llvm::Value *&numElements,
+                               llvm::Value *&allocPtr, CharUnits &cookieSize) {
+  assert(eltTy.isDestructedType());
+
+  // Derive a char* in the same address space as the pointer.
+  ptr = ptr.withElementType(CGF.Int8Ty);
+
+  cookieSize = getArrayCookieSizeImpl(eltTy);
+  Address allocAddr = CGF.Builder.CreateConstInBoundsByteGEP(ptr, -cookieSize);
+  allocPtr = allocAddr.emitRawPointer(CGF);
+  numElements = readArrayCookieImpl(CGF, allocAddr, cookieSize);
+}
+
 llvm::Value *CGCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
                                            Address ptr,
                                            CharUnits cookieSize) {

clang/lib/CodeGen/CGCXXABI.h

@@ -251,9 +251,10 @@ class CGCXXABI {
 
 public:
   virtual void emitVirtualObjectDelete(CodeGenFunction &CGF,
-                                       const CXXDeleteExpr *DE,
-                                       Address Ptr, QualType ElementType,
-                                       const CXXDestructorDecl *Dtor) = 0;
+                                       const CXXDeleteExpr *DE, Address Ptr,
+                                       QualType ElementType,
+                                       const CXXDestructorDecl *Dtor,
+                                       bool ArrayDeletion) = 0;
   virtual void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) = 0;
   virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0;
   virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; }
@@ -275,6 +276,7 @@ class CGCXXABI {
   virtual CatchTypeInfo getCatchAllTypeInfo();
 
   virtual bool shouldTypeidBeNullChecked(QualType SrcRecordTy) = 0;
+  virtual bool hasVectorDeletingDtors() = 0;
   virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0;
   virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
                                   Address ThisPtr,
@@ -485,11 +487,10 @@ class CGCXXABI {
       llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>;
 
   /// Emit the ABI-specific virtual destructor call.
-  virtual llvm::Value *
-  EmitVirtualDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *Dtor,
-                            CXXDtorType DtorType, Address This,
-                            DeleteOrMemberCallExpr E,
-                            llvm::CallBase **CallOrInvoke) = 0;
+  virtual llvm::Value *EmitVirtualDestructorCall(
+      CodeGenFunction &CGF, const CXXDestructorDecl *Dtor, CXXDtorType DtorType,
+      Address This, DeleteOrMemberCallExpr E, llvm::CallBase **CallOrInvoke,
+      bool ArrayDeletion = false) = 0;
 
   virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF,
                                                 GlobalDecl GD,
@@ -575,6 +576,12 @@ class CGCXXABI {
                                QualType ElementType, llvm::Value *&NumElements,
                                llvm::Value *&AllocPtr, CharUnits &CookieSize);
 
+  /// Reads the array cookie associated with the given pointer,
+  /// that should have one.
+  virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr,
+                               QualType ElementType, llvm::Value *&NumElements,
+                               llvm::Value *&AllocPtr, CharUnits &CookieSize);
+
   /// Return whether the given global decl needs a VTT parameter.
   virtual bool NeedsVTTParameter(GlobalDecl GD);