[modules] Don't write out name lookup table entries merely because the module

happened to query them; only write them out if something new was added.

llvm-svn: 230727

1 files changed, 13 insertions, 10 deletions

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 3af2a4003ba..c70935c0c7d 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3663,17 +3663,22 @@ public:
 } // end anonymous namespace
 
 template<typename Visitor>
-static void visitLocalLookupResults(const DeclContext *ConstDC,
-                                    bool NeedToReconcileExternalVisibleStorage,
-                                    Visitor AddLookupResult) {
+void ASTWriter::visitLocalLookupResults(const DeclContext *ConstDC,
+                                        Visitor AddLookupResult) {
   // FIXME: We need to build the lookups table, which is logically const.
   DeclContext *DC = const_cast<DeclContext*>(ConstDC);
   assert(DC == DC->getPrimaryContext() && "only primary DC has lookup table");
 
   SmallVector<DeclarationName, 16> ExternalNames;
   for (auto &Lookup : *DC->buildLookup()) {
+    // If there are no local declarations in our lookup result, we don't
+    // need to write an entry for the name at all unless we're rewriting
+    // the decl context.
+    if (!Lookup.second.hasLocalDecls() && !isRewritten(cast<Decl>(DC)))
+      continue;
+
     if (Lookup.second.hasExternalDecls() ||
-        NeedToReconcileExternalVisibleStorage) {
+        DC->NeedToReconcileExternalVisibleStorage) {
       // We don't know for sure what declarations are found by this name,
       // because the external source might have a different set from the set
       // that are in the lookup map, and we can't update it now without
@@ -3697,9 +3702,8 @@ static void visitLocalLookupResults(const DeclContext *ConstDC,
 void ASTWriter::AddUpdatedDeclContext(const DeclContext *DC) {
   if (UpdatedDeclContexts.insert(DC).second && WritingAST) {
     // Ensure we emit all the visible declarations.
-    visitLocalLookupResults(DC, DC->NeedToReconcileExternalVisibleStorage,
-                            [&](DeclarationName Name,
-                                DeclContext::lookup_result Result) {
+    visitLocalLookupResults(DC, [&](DeclarationName Name,
+                                    DeclContext::lookup_result Result) {
       for (auto *Decl : Result)
         GetDeclRef(getDeclForLocalLookup(getLangOpts(), Decl));
     });
@@ -3721,9 +3725,8 @@ ASTWriter::GenerateNameLookupTable(const DeclContext *DC,
   SmallVector<NamedDecl *, 8> ConstructorDecls;
   SmallVector<NamedDecl *, 4> ConversionDecls;
 
-  visitLocalLookupResults(DC, DC->NeedToReconcileExternalVisibleStorage,
-                          [&](DeclarationName Name,
-                              DeclContext::lookup_result Result) {
+  visitLocalLookupResults(DC, [&](DeclarationName Name,
+                                  DeclContext::lookup_result Result) {
     if (Result.empty())
       return;