Modular Codegen: Support homing debug info for types in modular objects

Matching the function-homing support for modular codegen. Any type
implicitly (implicit template specializations) or explicitly defined in
a module is attached to that module's object file and omitted elsewhere
(only a declaration used if necessary for references).

llvm-svn: 299987

8 files changed, 43 insertions, 11 deletions

diff --git a/clang/lib/AST/ExternalASTSource.cpp b/clang/lib/AST/ExternalASTSource.cpp
index 958a678..182d382 100644
--- a/clang/lib/AST/ExternalASTSource.cpp
+++ b/clang/lib/AST/ExternalASTSource.cpp
@@ -29,7 +29,7 @@ ExternalASTSource::getSourceDescriptor(unsigned ID) {
 }
 
 ExternalASTSource::ExtKind
-ExternalASTSource::hasExternalDefinitions(const FunctionDecl *FD) {
+ExternalASTSource::hasExternalDefinitions(const Decl *D) {
   return EK_ReplyHazy;
 }
 
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 05987be..818b515 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1820,6 +1820,10 @@ static bool shouldOmitDefinition(codegenoptions::DebugInfoKind DebugKind,
   if (DebugTypeExtRefs && isDefinedInClangModule(RD->getDefinition()))
     return true;
 
+  if (auto *ES = RD->getASTContext().getExternalSource())
+    if (ES->hasExternalDefinitions(RD) == ExternalASTSource::EK_Always)
+      return true;
+
   if (DebugKind > codegenoptions::LimitedDebugInfo)
     return false;
 
@@ -2552,11 +2556,17 @@ void CGDebugInfo::completeTemplateDefinition(
     const ClassTemplateSpecializationDecl &SD) {
   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
     return;
+  completeUnusedClass(SD);
+}
+
+void CGDebugInfo::completeUnusedClass(const CXXRecordDecl &D) {
+  if (DebugKind <= codegenoptions::DebugLineTablesOnly)
+    return;
 
-  completeClassData(&SD);
+  completeClassData(&D);
   // In case this type has no member function definitions being emitted, ensure
   // it is retained
-  RetainedTypes.push_back(CGM.getContext().getRecordType(&SD).getAsOpaquePtr());
+  RetainedTypes.push_back(CGM.getContext().getRecordType(&D).getAsOpaquePtr());
 }
 
 llvm::DIType *CGDebugInfo::getOrCreateType(QualType Ty, llvm::DIFile *Unit) {
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index c6d1c66..5050ca0 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -438,6 +438,7 @@ public:
   void completeClass(const RecordDecl *RD);
 
   void completeTemplateDefinition(const ClassTemplateSpecializationDecl &SD);
+  void completeUnusedClass(const CXXRecordDecl &D);
 
   /// Create debug info for a macro defined by a #define directive or a macro
   /// undefined by a #undef directive.
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 96358bf..7fe8bf0 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3820,6 +3820,11 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
     EmitDeclContext(cast<NamespaceDecl>(D));
     break;
   case Decl::CXXRecord:
+    if (DebugInfo) {
+      if (auto *ES = D->getASTContext().getExternalSource())
+        if (ES->hasExternalDefinitions(D) == ExternalASTSource::EK_Never)
+          DebugInfo->completeUnusedClass(cast<CXXRecordDecl>(*D));
+    }
     // Emit any static data members, they may be definitions.
     for (auto *I : cast<CXXRecordDecl>(D)->decls())
       if (isa<VarDecl>(I) || isa<CXXRecordDecl>(I))
diff --git a/clang/lib/Sema/MultiplexExternalSemaSource.cpp b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
index f749b7d..b7e343c 100644
--- a/clang/lib/Sema/MultiplexExternalSemaSource.cpp
+++ b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
@@ -95,9 +95,9 @@ MultiplexExternalSemaSource::GetExternalCXXCtorInitializers(uint64_t Offset) {
 }
 
 ExternalASTSource::ExtKind
-MultiplexExternalSemaSource::hasExternalDefinitions(const FunctionDecl *FD) {
+MultiplexExternalSemaSource::hasExternalDefinitions(const Decl *D) {
   for (const auto &S : Sources)
-    if (auto EK = S->hasExternalDefinitions(FD))
+    if (auto EK = S->hasExternalDefinitions(D))
       if (EK != EK_ReplyHazy)
         return EK;
   return EK_ReplyHazy;
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index a51f144..322fc86 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -8147,8 +8147,7 @@ ASTReader::getSourceDescriptor(unsigned ID) {
   return None;
 }
 
-ExternalASTSource::ExtKind
-ASTReader::hasExternalDefinitions(const FunctionDecl *FD) {
+ExternalASTSource::ExtKind ASTReader::hasExternalDefinitions(const Decl *FD) {
   auto I = BodySource.find(FD);
   if (I == BodySource.end())
     return EK_ReplyHazy;
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 9b9b41a..db7d55e 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -119,7 +119,8 @@ namespace clang {
     }
 
     void ReadCXXRecordDefinition(CXXRecordDecl *D, bool Update);
-    void ReadCXXDefinitionData(struct CXXRecordDecl::DefinitionData &Data);
+    void ReadCXXDefinitionData(struct CXXRecordDecl::DefinitionData &Data,
+                               const CXXRecordDecl *D);
     void MergeDefinitionData(CXXRecordDecl *D,
                              struct CXXRecordDecl::DefinitionData &&NewDD);
     void ReadObjCDefinitionData(struct ObjCInterfaceDecl::DefinitionData &Data);
@@ -1490,7 +1491,7 @@ void ASTDeclReader::VisitUnresolvedUsingTypenameDecl(
 }
 
 void ASTDeclReader::ReadCXXDefinitionData(
-                                   struct CXXRecordDecl::DefinitionData &Data) {
+    struct CXXRecordDecl::DefinitionData &Data, const CXXRecordDecl *D) {
   // Note: the caller has deserialized the IsLambda bit already.
   Data.UserDeclaredConstructor = Record.readInt();
   Data.UserDeclaredSpecialMembers = Record.readInt();
@@ -1536,6 +1537,12 @@ void ASTDeclReader::ReadCXXDefinitionData(
   Data.HasDeclaredCopyAssignmentWithConstParam = Record.readInt();
   Data.ODRHash = Record.readInt();
 
+  if (Record.readInt()) {
+    Reader.BodySource[D] = Loc.F->Kind == ModuleKind::MK_MainFile
+                               ? ExternalASTSource::EK_Never
+                               : ExternalASTSource::EK_Always;
+  }
+
   Data.NumBases = Record.readInt();
   if (Data.NumBases)
     Data.Bases = ReadGlobalOffset();
@@ -1707,7 +1714,7 @@ void ASTDeclReader::ReadCXXRecordDefinition(CXXRecordDecl *D, bool Update) {
   else
     DD = new (C) struct CXXRecordDecl::DefinitionData(D);
 
-  ReadCXXDefinitionData(*DD);
+  ReadCXXDefinitionData(*DD, D);
 
   // We might already have a definition for this record. This can happen either
   // because we're reading an update record, or because we've already done some
@@ -2553,7 +2560,11 @@ static bool isConsumerInterestedIn(ASTContext &Ctx, Decl *D, bool HasBody) {
            Var->isThisDeclarationADefinition() == VarDecl::Definition;
   if (FunctionDecl *Func = dyn_cast<FunctionDecl>(D))
     return Func->doesThisDeclarationHaveABody() || HasBody;
-  
+
+  if (auto *ES = D->getASTContext().getExternalSource())
+    if (ES->hasExternalDefinitions(D) == ExternalASTSource::EK_Never)
+      return true;
+
   return false;
 }
 
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 23859c2..ec59250 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -5770,6 +5770,12 @@ void ASTRecordWriter::AddCXXDefinitionData(const CXXRecordDecl *D) {
   Record->push_back(Data.HasDeclaredCopyConstructorWithConstParam);
   Record->push_back(Data.HasDeclaredCopyAssignmentWithConstParam);
   Record->push_back(Data.ODRHash);
+  bool ModularCodegen = Writer->Context->getLangOpts().ModularCodegen &&
+                        Writer->WritingModule && !D->isDependentType();
+  Record->push_back(ModularCodegen);
+  if (ModularCodegen)
+    Writer->ModularCodegenDecls.push_back(Writer->GetDeclRef(D));
+
   // IsLambda bit is already saved.
 
   Record->push_back(Data.NumBases);