[modules] Teach the ASTWriter to ignore mutations coming from the ASTReader.

Processing update records (and loading a module, in general) might trigger
unexpected calls to the ASTWriter (being a mutation listener). Now we have a
mechanism to suppress those calls to the ASTWriter but notify other possible
mutation listeners.

Fixes https://llvm.org/bugs/show_bug.cgi?id=28332

Patch by Cristina Cristescu and me.

Reviewed by Richard Smith (D21800).

llvm-svn: 276473

3 files changed, 23 insertions, 10 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 6bfae07b82b..27b7048f375 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -8644,6 +8644,7 @@ void ASTReader::FinishedDeserializing() {
       auto Updates = std::move(PendingExceptionSpecUpdates);
       PendingExceptionSpecUpdates.clear();
       for (auto Update : Updates) {
+        ProcessingUpdatesRAIIObj ProcessingUpdates(*this);
         auto *FPT = Update.second->getType()->castAs<FunctionProtoType>();
         auto ESI = FPT->getExtProtoInfo().ExceptionSpec;
         if (auto *Listener = Context.getASTMutationListener())
@@ -8714,6 +8715,7 @@ ASTReader::ASTReader(
       AllowConfigurationMismatch(AllowConfigurationMismatch),
       ValidateSystemInputs(ValidateSystemInputs),
       UseGlobalIndex(UseGlobalIndex), TriedLoadingGlobalIndex(false),
+      ProcessingUpdateRecords(false),
       CurrSwitchCaseStmts(&SwitchCaseStmts), NumSLocEntriesRead(0),
       TotalNumSLocEntries(0), NumStatementsRead(0), TotalNumStatements(0),
       NumMacrosRead(0), TotalNumMacros(0), NumIdentifierLookups(0),
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 184e7efe84f..b5384bbc39e 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -3489,6 +3489,7 @@ void ASTReader::loadDeclUpdateRecords(serialization::DeclID ID, Decl *D) {
   // The declaration may have been modified by files later in the chain.
   // If this is the case, read the record containing the updates from each file
   // and pass it to ASTDeclReader to make the modifications.
+  ProcessingUpdatesRAIIObj ProcessingUpdates(*this);
   DeclUpdateOffsetsMap::iterator UpdI = DeclUpdateOffsets.find(ID);
   if (UpdI != DeclUpdateOffsets.end()) {
     auto UpdateOffsets = std::move(UpdI->second);
@@ -3907,11 +3908,8 @@ void ASTDeclReader::UpdateDecl(Decl *D, ModuleFile &ModuleFile,
     }
 
     case UPD_DECL_MARKED_USED: {
-      // FIXME: This doesn't send the right notifications if there are
-      // ASTMutationListeners other than an ASTWriter.
-
       // Maintain AST consistency: any later redeclarations are used too.
-      D->setIsUsed();
+      D->markUsed(Reader.Context);
       break;
     }
 
@@ -3935,11 +3933,8 @@ void ASTDeclReader::UpdateDecl(Decl *D, ModuleFile &ModuleFile,
         Exported = TD->getDefinition();
       Module *Owner = SubmoduleID ? Reader.getSubmodule(SubmoduleID) : nullptr;
       if (Reader.getContext().getLangOpts().ModulesLocalVisibility) {
-        // FIXME: This doesn't send the right notifications if there are
-        // ASTMutationListeners other than an ASTWriter.
-        Reader.getContext().mergeDefinitionIntoModule(
-            cast<NamedDecl>(Exported), Owner,
-            /*NotifyListeners*/ false);
+        Reader.getContext().mergeDefinitionIntoModule(cast<NamedDecl>(Exported),
+                                                      Owner);
         Reader.PendingMergedDefinitionsToDeduplicate.insert(
             cast<NamedDecl>(Exported));
       } else if (Owner && Owner->NameVisibility != Module::AllVisible) {
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index dbba5fd1913..9a1e4f6778b 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -5657,6 +5657,7 @@ void ASTWriter::ModuleRead(serialization::SubmoduleID ID, Module *Mod) {
 }
 
 void ASTWriter::CompletedTagDefinition(const TagDecl *D) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(D->isCompleteDefinition());
   assert(!WritingAST && "Already writing the AST!");
   if (auto *RD = dyn_cast<CXXRecordDecl>(D)) {
@@ -5683,7 +5684,8 @@ static bool isImportedDeclContext(ASTReader *Chain, const Decl *D) {
 }
 
 void ASTWriter::AddedVisibleDecl(const DeclContext *DC, const Decl *D) {
-   assert(DC->isLookupContext() &&
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
+  assert(DC->isLookupContext() &&
           "Should not add lookup results to non-lookup contexts!");
 
   // TU is handled elsewhere.
@@ -5717,6 +5719,7 @@ void ASTWriter::AddedVisibleDecl(const DeclContext *DC, const Decl *D) {
 }
 
 void ASTWriter::AddedCXXImplicitMember(const CXXRecordDecl *RD, const Decl *D) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(D->isImplicit());
 
   // We're only interested in cases where a local declaration is added to an
@@ -5734,6 +5737,7 @@ void ASTWriter::AddedCXXImplicitMember(const CXXRecordDecl *RD, const Decl *D) {
 }
 
 void ASTWriter::ResolvedExceptionSpec(const FunctionDecl *FD) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!DoneWritingDeclsAndTypes && "Already done writing updates!");
   if (!Chain) return;
   Chain->forEachImportedKeyDecl(FD, [&](const Decl *D) {
@@ -5748,6 +5752,7 @@ void ASTWriter::ResolvedExceptionSpec(const FunctionDecl *FD) {
 }
 
 void ASTWriter::DeducedReturnType(const FunctionDecl *FD, QualType ReturnType) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!Chain) return;
   Chain->forEachImportedKeyDecl(FD, [&](const Decl *D) {
@@ -5758,6 +5763,7 @@ void ASTWriter::DeducedReturnType(const FunctionDecl *FD, QualType ReturnType) {
 
 void ASTWriter::ResolvedOperatorDelete(const CXXDestructorDecl *DD,
                                        const FunctionDecl *Delete) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   assert(Delete && "Not given an operator delete");
   if (!Chain) return;
@@ -5767,6 +5773,7 @@ void ASTWriter::ResolvedOperatorDelete(const CXXDestructorDecl *DD,
 }
 
 void ASTWriter::CompletedImplicitDefinition(const FunctionDecl *D) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!D->isFromASTFile())
     return; // Declaration not imported from PCH.
@@ -5776,6 +5783,7 @@ void ASTWriter::CompletedImplicitDefinition(const FunctionDecl *D) {
 }
 
 void ASTWriter::FunctionDefinitionInstantiated(const FunctionDecl *D) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!D->isFromASTFile())
     return;
@@ -5784,6 +5792,7 @@ void ASTWriter::FunctionDefinitionInstantiated(const FunctionDecl *D) {
 }
 
 void ASTWriter::StaticDataMemberInstantiated(const VarDecl *D) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!D->isFromASTFile())
     return;
@@ -5796,6 +5805,7 @@ void ASTWriter::StaticDataMemberInstantiated(const VarDecl *D) {
 }
 
 void ASTWriter::DefaultArgumentInstantiated(const ParmVarDecl *D) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!D->isFromASTFile())
     return;
@@ -5806,6 +5816,7 @@ void ASTWriter::DefaultArgumentInstantiated(const ParmVarDecl *D) {
 
 void ASTWriter::AddedObjCCategoryToInterface(const ObjCCategoryDecl *CatD,
                                              const ObjCInterfaceDecl *IFD) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!IFD->isFromASTFile())
     return; // Declaration not imported from PCH.
@@ -5816,6 +5827,7 @@ void ASTWriter::AddedObjCCategoryToInterface(const ObjCCategoryDecl *CatD,
 }
 
 void ASTWriter::DeclarationMarkedUsed(const Decl *D) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
 
   // If there is *any* declaration of the entity that's not from an AST file,
@@ -5829,6 +5841,7 @@ void ASTWriter::DeclarationMarkedUsed(const Decl *D) {
 }
 
 void ASTWriter::DeclarationMarkedOpenMPThreadPrivate(const Decl *D) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!D->isFromASTFile())
     return;
@@ -5838,6 +5851,7 @@ void ASTWriter::DeclarationMarkedOpenMPThreadPrivate(const Decl *D) {
 
 void ASTWriter::DeclarationMarkedOpenMPDeclareTarget(const Decl *D,
                                                      const Attr *Attr) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!D->isFromASTFile())
     return;
@@ -5847,6 +5861,7 @@ void ASTWriter::DeclarationMarkedOpenMPDeclareTarget(const Decl *D,
 }
 
 void ASTWriter::RedefinedHiddenDefinition(const NamedDecl *D, Module *M) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   assert(D->isHidden() && "expected a hidden declaration");
   DeclUpdates[D].push_back(DeclUpdate(UPD_DECL_EXPORTED, M));
@@ -5854,6 +5869,7 @@ void ASTWriter::RedefinedHiddenDefinition(const NamedDecl *D, Module *M) {
 
 void ASTWriter::AddedAttributeToRecord(const Attr *Attr,
                                        const RecordDecl *Record) {
+  if (Chain && Chain->isProcessingUpdateRecords()) return;
   assert(!WritingAST && "Already writing the AST!");
   if (!Record->isFromASTFile())
     return;