Modular Codegen: Add/use a bit in serialized function definitions to track whether they are the subject of modular codegen

Some decls are created not where they are written, but in other module
files/users (implicit special members and function template implicit
specializations). To correctly identify them, use a bit next to the definition
to track the modular codegen property.

Discussed whether the module file bit could be omitted in favor of
reconstituting from the modular codegen decls list - best guess today is that
the efficiency improvement of not having to deserialize the whole list whenever
any function is queried by a module user is worth it for the small size
increase of this redundant (list + bit-on-def) representation.

Reviewers: rsmith

Differential Revision: https://reviews.llvm.org/D29901

llvm-svn: 299982

1 files changed, 1 insertions, 3 deletions

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 9b479c24e20..23859c241d5 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -2627,7 +2627,6 @@ void ASTWriter::WriteSubmodules(Module *WritingModule) {
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InferExplicit...
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InferExportWild...
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ConfigMacrosExh...
-  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // WithCodegen
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // Name
   unsigned DefinitionAbbrev = Stream.EmitAbbrev(std::move(Abbrev));
 
@@ -2726,8 +2725,7 @@ void ASTWriter::WriteSubmodules(Module *WritingModule) {
                                          Mod->InferSubmodules,
                                          Mod->InferExplicitSubmodules,
                                          Mod->InferExportWildcard,
-                                         Mod->ConfigMacrosExhaustive,
-                                         Context->getLangOpts().ModularCodegen && WritingModule};
+                                         Mod->ConfigMacrosExhaustive};
       Stream.EmitRecordWithBlob(DefinitionAbbrev, Record, Mod->Name);
     }