Set a special flag in class metadata when an Objective-C class

has ivars that require destruction, but none that require anything
except zero-initialization.  This is common in ARC and (when true
throughout a class hierarchy) permits the elimination of an
unnecessary message-send during allocation.

llvm-svn: 166088

2 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index d85cb4e..17509c8 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -855,6 +855,8 @@ void ASTDeclReader::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
   D->setSuperClass(ReadDeclAs<ObjCInterfaceDecl>(Record, Idx));
   D->setIvarLBraceLoc(ReadSourceLocation(Record, Idx));
   D->setIvarRBraceLoc(ReadSourceLocation(Record, Idx));
+  D->setHasNonZeroConstructors(Record[Idx++]);
+  D->setHasDestructors(Record[Idx++]);
   llvm::tie(D->IvarInitializers, D->NumIvarInitializers)
       = Reader.ReadCXXCtorInitializers(F, Record, Idx);
 }
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 2270e8f..e84afba5 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -606,6 +606,8 @@ void ASTDeclWriter::VisitObjCImplementationDecl(ObjCImplementationDecl *D) {
   Writer.AddDeclRef(D->getSuperClass(), Record);
   Writer.AddSourceLocation(D->getIvarLBraceLoc(), Record);
   Writer.AddSourceLocation(D->getIvarRBraceLoc(), Record);
+  Record.push_back(D->hasNonZeroConstructors());
+  Record.push_back(D->hasDestructors());
   Writer.AddCXXCtorInitializers(D->IvarInitializers, D->NumIvarInitializers,
                                 Record);
   Code = serialization::DECL_OBJC_IMPLEMENTATION;