merge main into amd-staging

xfails:
* clang/test/CodeGenCXX/modules-vtable.cppm
* clang/test/CodeGenCXX/pr70585.cppm

cause:
llvm#75912
[C++20] [Modules] [Itanium ABI] Generate the vtable in
the module unit of dynamic classes

Change-Id: I7c502ffc1fe6bc7f98f3a60bc6c7bfe0af52b497

Author: animeshk-amd

clang/include/clang/AST/DeclBase.h

@@ -670,6 +670,16 @@ class alignas(8) Decl {
   /// Whether this declaration comes from another module unit.
   bool isInAnotherModuleUnit() const;
 
+  /// Whether this declaration comes from the same module unit being compiled.
+  bool isInCurrentModuleUnit() const;
+
+  /// Whether the definition of the declaration should be emitted in external
+  /// sources.
+  bool shouldEmitInExternalSource() const;
+
+  /// Whether this declaration comes from a named module;
+  bool isInNamedModule() const;
+
   /// Whether this declaration comes from explicit global module.
   bool isFromExplicitGlobalModule() const;
 

clang/include/clang/Serialization/ASTBitCodes.h

@@ -697,6 +697,9 @@ enum ASTRecordTypes {
 
   /// Record code for \#pragma clang unsafe_buffer_usage begin/end
   PP_UNSAFE_BUFFER_USAGE = 69,
+
+  /// Record code for vtables to emit.
+  VTABLES_TO_EMIT = 70,
 };
 
 /// Record types used within a source manager block.

clang/include/clang/Serialization/ASTReader.h

@@ -805,6 +805,11 @@ class ASTReader
   /// the consumer eagerly.
   SmallVector<GlobalDeclID, 16> EagerlyDeserializedDecls;
 
+  /// The IDs of all vtables to emit. The referenced declarations are passed
+  /// to the consumers's HandleVTable eagerly after passing
+  /// EagerlyDeserializedDecls.
+  SmallVector<GlobalDeclID, 16> VTablesToEmit;
+
   /// The IDs of all tentative definitions stored in the chain.
   ///
   /// Sema keeps track of all tentative definitions in a TU because it has to
@@ -1514,6 +1519,7 @@ class ASTReader
   bool isConsumerInterestedIn(Decl *D);
   void PassInterestingDeclsToConsumer();
   void PassInterestingDeclToConsumer(Decl *D);
+  void PassVTableToConsumer(CXXRecordDecl *RD);
 
   void finishPendingActions();
   void diagnoseOdrViolations();

clang/include/clang/Serialization/ASTWriter.h

@@ -495,6 +495,10 @@ class ASTWriter : public ASTDeserializationListener,
   std::vector<SourceRange> NonAffectingRanges;
   std::vector<SourceLocation::UIntTy> NonAffectingOffsetAdjustments;
 
+  /// A list of classes which need to emit the VTable in the corresponding
+  /// object file.
+  llvm::SmallVector<CXXRecordDecl *> PendingEmittingVTables;
+
   /// Computes input files that didn't affect compilation of the current module,
   /// and initializes data structures necessary for leaving those files out
   /// during \c SourceManager serialization.
@@ -849,6 +853,8 @@ class ASTWriter : public ASTDeserializationListener,
 
   bool getDoneWritingDeclsAndTypes() const { return DoneWritingDeclsAndTypes; }
 
+  void handleVTable(CXXRecordDecl *RD);
+
 private:
   // ASTDeserializationListener implementation
   void ReaderInitialized(ASTReader *Reader) override;
@@ -943,6 +949,7 @@ class PCHGenerator : public SemaConsumer {
 
   void InitializeSema(Sema &S) override { SemaPtr = &S; }
   void HandleTranslationUnit(ASTContext &Ctx) override;
+  void HandleVTable(CXXRecordDecl *RD) override { Writer.handleVTable(RD); }
   ASTMutationListener *GetASTMutationListener() override;
   ASTDeserializationListener *GetASTDeserializationListener() override;
   bool hasEmittedPCH() const { return Buffer->IsComplete; }

clang/lib/AST/Decl.cpp

@@ -1190,7 +1190,7 @@ static bool isExportedFromModuleInterfaceUnit(const NamedDecl *D) {
     return false;
   case Decl::ModuleOwnershipKind::Visible:
   case Decl::ModuleOwnershipKind::VisibleWhenImported:
-    return isInNamedModule(D);
+    return D->isInNamedModule();
   }
   llvm_unreachable("unexpected module ownership kind");
 }
@@ -1208,7 +1208,7 @@ Linkage NamedDecl::getFormalLinkage() const {
   // [basic.namespace.general]/p2
   //   A namespace is never attached to a named module and never has a name with
   //   module linkage.
-  if (isInNamedModule(this) && InternalLinkage == Linkage::External &&
+  if (isInNamedModule() && InternalLinkage == Linkage::External &&
       !isExportedFromModuleInterfaceUnit(
           cast<NamedDecl>(this->getCanonicalDecl())) &&
       !isa<NamespaceDecl>(this))

clang/lib/AST/DeclBase.cpp

@@ -1141,6 +1141,28 @@ bool Decl::isInAnotherModuleUnit() const {
   return M != getASTContext().getCurrentNamedModule();
 }
 
+
+bool Decl::isInCurrentModuleUnit() const {
+  auto *M = getOwningModule();
+
+  if (!M || !M->isNamedModule())
+    return false;
+
+  return M == getASTContext().getCurrentNamedModule();
+}
+
+bool Decl::shouldEmitInExternalSource() const {
+  ExternalASTSource *Source = getASTContext().getExternalSource();
+  if (!Source)
+    return false;
+
+  return Source->hasExternalDefinitions(this) == ExternalASTSource::EK_Always;
+}
+
+bool Decl::isInNamedModule() const {
+  return getOwningModule() && getOwningModule()->isNamedModule();
+}
+
 bool Decl::isFromExplicitGlobalModule() const {
   return getOwningModule() && getOwningModule()->isExplicitGlobalModule();
 }

clang/lib/Basic/Targets/AArch64.cpp

@@ -220,6 +220,18 @@ bool AArch64TargetInfo::validateTarget(DiagnosticsEngine &Diags) const {
   return true;
 }
 
+bool AArch64TargetInfo::validateGlobalRegisterVariable(
+    StringRef RegName, unsigned RegSize, bool &HasSizeMismatch) const {
+  if ((RegName == "sp") || RegName.starts_with("x")) {
+    HasSizeMismatch = RegSize != 64;
+    return true;
+  } else if (RegName.starts_with("w")) {
+    HasSizeMismatch = RegSize != 32;
+    return true;
+  }
+  return false;
+}
+
 bool AArch64TargetInfo::validateBranchProtection(StringRef Spec, StringRef,
                                                  BranchProtectionInfo &BPI,
                                                  StringRef &Err) const {

clang/lib/Basic/Targets/AArch64.h

@@ -202,6 +202,9 @@ class LLVM_LIBRARY_VISIBILITY AArch64TargetInfo : public TargetInfo {
   bool hasBitIntType() const override { return true; }
 
   bool validateTarget(DiagnosticsEngine &Diags) const override;
+
+  bool validateGlobalRegisterVariable(StringRef RegName, unsigned RegSize,
+                                      bool &HasSizeMismatch) const override;
 };
 
 class LLVM_LIBRARY_VISIBILITY AArch64leTargetInfo : public AArch64TargetInfo {

clang/lib/CodeGen/CGVTables.cpp

@@ -1052,6 +1052,11 @@ CodeGenModule::getVTableLinkage(const CXXRecordDecl *RD) {
   if (!RD->isExternallyVisible())
     return llvm::GlobalVariable::InternalLinkage;
 
+  // V-tables for non-template classes with an owning module are always
+  // uniquely emitted in that module.
+  if (RD->isInNamedModule())
+    return llvm::GlobalVariable::ExternalLinkage;
+
   // We're at the end of the translation unit, so the current key
   // function is fully correct.
   const CXXMethodDecl *keyFunction = Context.getCurrentKeyFunction(RD);
@@ -1186,6 +1191,21 @@ bool CodeGenVTables::isVTableExternal(const CXXRecordDecl *RD) {
       TSK == TSK_ExplicitInstantiationDefinition)
     return false;
 
+  // Itanium C++ ABI [5.2.3]:
+  // Virtual tables for dynamic classes are emitted as follows:
+  //
+  // - If the class is templated, the tables are emitted in every object that
+  // references any of them.
+  // - Otherwise, if the class is attached to a module, the tables are uniquely
+  // emitted in the object for the module unit in which it is defined.
+  // - Otherwise, if the class has a key function (see below), the tables are
+  // emitted in the object for the translation unit containing the definition of
+  // the key function. This is unique if the key function is not inline.
+  // - Otherwise, the tables are emitted in every object that references any of
+  // them.
+  if (RD->isInNamedModule())
+    return RD->shouldEmitInExternalSource();
+
   // Otherwise, if the class doesn't have a key function (possibly
   // anymore), the vtable must be defined here.
   const CXXMethodDecl *keyFunction = CGM.getContext().getCurrentKeyFunction(RD);
@@ -1195,13 +1215,7 @@ bool CodeGenVTables::isVTableExternal(const CXXRecordDecl *RD) {
   const FunctionDecl *Def;
   // Otherwise, if we don't have a definition of the key function, the
   // vtable must be defined somewhere else.
-  if (!keyFunction->hasBody(Def))
-    return true;
-
-  assert(Def && "The body of the key function is not assigned to Def?");
-  // If the non-inline key function comes from another module unit, the vtable
-  // must be defined there.
-  return Def->isInAnotherModuleUnit() && !Def->isInlineSpecified();
+  return !keyFunction->hasBody(Def);
 }
 
 /// Given that we're currently at the end of the translation unit, and

clang/lib/CodeGen/ItaniumCXXABI.cpp

@@ -2130,6 +2130,9 @@ bool ItaniumCXXABI::canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const {
   if (!canSpeculativelyEmitVTableAsBaseClass(RD))
     return false;
 
+  if (RD->shouldEmitInExternalSource())
+    return false;
+
   // For a complete-object vtable (or more specifically, for the VTT), we need
   // to be able to speculatively emit the vtables of all dynamic virtual bases.
   for (const auto &B : RD->vbases()) {