[clang] MicrosoftCXXABI: restore the RecordToCopyCtor table when loading AST (#53486)

- Includes a regression test for the issue

Author: glebov-andrey

clang/include/clang/AST/ASTContext.h

@@ -682,6 +682,8 @@ class ASTContext : public RefCountedBase<ASTContext> {
   /// For performance, track whether any function effects are in use.
   mutable bool AnyFunctionEffects = false;
 
+  bool ExternalCopyConstructorsForExceptionObjectsLoaded = false;
+
   const TargetInfo *Target = nullptr;
   const TargetInfo *AuxTarget = nullptr;
   clang::PrintingPolicy PrintingPolicy;
@@ -3362,6 +3364,9 @@ class ASTContext : public RefCountedBase<ASTContext> {
       const FunctionDecl *FD,
       llvm::function_ref<void(FunctionDecl *)> Pred) const;
 
+  llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> *
+  getRecordToCopyCtor();
+
   const CXXConstructorDecl *
   getCopyConstructorForExceptionObject(CXXRecordDecl *RD);
 

clang/include/clang/AST/ExternalASTSource.h

@@ -40,6 +40,7 @@ class ASTConsumer;
 class ASTContext;
 class ASTSourceDescriptor;
 class CXXBaseSpecifier;
+class CXXConstructorDecl;
 class CXXCtorInitializer;
 class CXXRecordDecl;
 class DeclarationName;
@@ -175,6 +176,9 @@ class ExternalASTSource : public RefCountedBase<ExternalASTSource> {
   LoadExternalSpecializations(const Decl *D,
                               ArrayRef<TemplateArgument> TemplateArgs);
 
+  virtual void LoadExternalExceptionCopyingConstructors(
+      llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> &RecordToCtor);
+
   /// Ensures that the table of all visible declarations inside this
   /// context is up to date.
   ///

clang/include/clang/Sema/MultiplexExternalSemaSource.h

@@ -106,6 +106,10 @@ class MultiplexExternalSemaSource : public ExternalSemaSource {
   LoadExternalSpecializations(const Decl *D,
                               ArrayRef<TemplateArgument> TemplateArgs) override;
 
+  void LoadExternalExceptionCopyingConstructors(
+      llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> &RecordToCtor)
+      override;
+
   /// Ensures that the table of all visible declarations inside this
   /// context is up to date.
   void completeVisibleDeclsMap(const DeclContext *DC) override;

clang/include/clang/Serialization/ASTBitCodes.h

@@ -742,6 +742,8 @@ enum ASTRecordTypes {
   UPDATE_MODULE_LOCAL_VISIBLE = 76,
 
   UPDATE_TU_LOCAL_VISIBLE = 77,
+
+  MSCXXABI_EXCEPTION_COPYING_CONSTRUCTORS = 78,
 };
 
 /// Record types used within a source manager block.

clang/include/clang/Serialization/ASTReader.h

@@ -1055,6 +1055,12 @@ class ASTReader
   /// The IDs of all decls with function effects to be checked.
   SmallVector<GlobalDeclID> DeclsWithEffectsToVerify;
 
+  struct RecordAndCopyingCtor {
+    GlobalDeclID RecordID;
+    GlobalDeclID CtorID;
+  };
+  SmallVector<RecordAndCopyingCtor> RecordToCopyingCtor;
+
 private:
   struct ImportedSubmodule {
     serialization::SubmoduleID ID;
@@ -2177,6 +2183,10 @@ class ASTReader
   LoadExternalSpecializations(const Decl *D,
                               ArrayRef<TemplateArgument> TemplateArgs) override;
 
+  void LoadExternalExceptionCopyingConstructors(
+      llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> &RecordToCtor)
+      override;
+
   /// Finds all the visible declarations with a given name.
   /// The current implementation of this method just loads the entire
   /// lookup table as unmaterialized references.

clang/lib/AST/ASTContext.cpp

@@ -13333,8 +13333,25 @@ ASTContext::createMangleNumberingContext() const {
   return ABI->createMangleNumberingContext();
 }
 
+llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> *
+ASTContext::getRecordToCopyCtor() {
+  if (ABI) { // TODO Why can this be null?
+    return ABI->getRecordToCopyCtor();
+  }
+  return nullptr;
+}
+
 const CXXConstructorDecl *
 ASTContext::getCopyConstructorForExceptionObject(CXXRecordDecl *RD) {
+  if (!getTargetInfo().getCXXABI().isMicrosoft()) {
+    return nullptr;
+  }
+  if (ExternalSource && !ExternalCopyConstructorsForExceptionObjectsLoaded) {
+    auto *Map = ABI->getRecordToCopyCtor();
+    assert(Map);
+    ExternalSource->LoadExternalExceptionCopyingConstructors(*Map);
+    ExternalCopyConstructorsForExceptionObjectsLoaded = true;
+  }
   return ABI->getCopyConstructorForExceptionObject(
       cast<CXXRecordDecl>(RD->getFirstDecl()));
 }

clang/lib/AST/CXXABI.h

@@ -56,6 +56,9 @@ class CXXABI {
   virtual void addCopyConstructorForExceptionObject(CXXRecordDecl *,
                                                     CXXConstructorDecl *) = 0;
 
+  virtual llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> *
+  getRecordToCopyCtor() = 0;
+
   /// Retrieves the mapping from class to copy constructor for this C++ ABI.
   virtual const CXXConstructorDecl *
   getCopyConstructorForExceptionObject(CXXRecordDecl *) = 0;

clang/lib/AST/ExternalASTSource.cpp

@@ -109,6 +109,9 @@ bool ExternalASTSource::LoadExternalSpecializations(
   return false;
 }
 
+void ExternalASTSource::LoadExternalExceptionCopyingConstructors(
+    llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> &) {}
+
 void ExternalASTSource::completeVisibleDeclsMap(const DeclContext *DC) {}
 
 void ExternalASTSource::FindExternalLexicalDecls(

clang/lib/AST/ItaniumCXXABI.cpp

@@ -256,6 +256,11 @@ class ItaniumCXXABI : public CXXABI {
     return Layout.getNonVirtualSize() == PointerSize;
   }
 
+  llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> *
+  getRecordToCopyCtor() override {
+    return nullptr;
+  }
+
   const CXXConstructorDecl *
   getCopyConstructorForExceptionObject(CXXRecordDecl *RD) override {
     return nullptr;

clang/lib/AST/MicrosoftCXXABI.cpp

@@ -146,6 +146,11 @@ class MicrosoftCXXABI : public CXXABI {
     llvm_unreachable("unapplicable to the MS ABI");
   }
 
+  llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> *
+  getRecordToCopyCtor() override {
+    return &RecordToCopyCtor;
+  }
+
   const CXXConstructorDecl *
   getCopyConstructorForExceptionObject(CXXRecordDecl *RD) override {
     return RecordToCopyCtor[RD];