Do not omit data from imported modules with same keyusers/ChuanqiXu9/D41416_on_disk_hash_table_polishing

2 files changed, 7 insertions, 3 deletions

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 0b0c555..e07cc26 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -4245,7 +4245,11 @@ void ASTWriter::GenerateSpecializationInfoLookupTable(
 
   auto *Lookups =
       Chain ? Chain->getLoadedSpecializationsLookupTables(D) : nullptr;
-  Generator.emit(LookupTable, Trait, Lookups ? &Lookups->Table : nullptr);
+  // We can't OmitDataWithSameKeyInBase since the lazy load specialization
+  // mechanism assumes that different specializations can share the same
+  // hash key.
+  Generator.emit(LookupTable, Trait, Lookups ? &Lookups->Table : nullptr,
+                 /*OmitDataWithSameKeyInBase=*/false);
 }
 
 uint64_t ASTWriter::WriteSpecializationInfoLookupTable(
diff --git a/clang/lib/Serialization/MultiOnDiskHashTable.h b/clang/lib/Serialization/MultiOnDiskHashTable.h
index a0d75ec..76910f4 100644
--- a/clang/lib/Serialization/MultiOnDiskHashTable.h
+++ b/clang/lib/Serialization/MultiOnDiskHashTable.h
@@ -306,7 +306,7 @@ public:
   }
 
   void emit(llvm::SmallVectorImpl<char> &Out, WriterInfo &Info,
-            const BaseTable *Base) {
+            const BaseTable *Base, bool OmitDataWithSameKeyInBase = true) {
     using namespace llvm::support;
 
     llvm::raw_svector_ostream OutStream(Out);
@@ -326,7 +326,7 @@ public:
 
         // Add all merged entries from Base to the generator.
         for (auto &KV : Merged->Data) {
-          if (!Gen.contains(KV.first, Info))
+          if (!OmitDataWithSameKeyInBase || !Gen.contains(KV.first, Info))
             Gen.insert(KV.first, Info.ImportData(KV.second), Info);
         }
       } else {