[ObjC] Allow declaring __weak pointer fields in C structs in ARC.

This patch uses the infrastructure added in r326307 for enabling
non-trivial fields to be declared in C structs to allow __weak fields in
C structs in ARC.

This recommits r327206, which was reverted because it caused
module-enabled builders to fail. I discovered that the
CXXRecordDecl::CanPassInRegisters flag wasn't being set correctly in
some cases after I moved it to RecordDecl.

Thanks to Eric Liu for helping me investigate the bug.

rdar://problem/33599681

https://reviews.llvm.org/D44095

llvm-svn: 327870

1 files changed, 2 insertions, 2 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index ab99a170799..733748c2932 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -742,6 +742,7 @@ ASTDeclReader::VisitRecordDeclImpl(RecordDecl *RD) {
   RD->setNonTrivialToPrimitiveDefaultInitialize(Record.readInt());
   RD->setNonTrivialToPrimitiveCopy(Record.readInt());
   RD->setNonTrivialToPrimitiveDestroy(Record.readInt());
+  RD->setCanPassInRegisters(Record.readInt());
   return Redecl;
 }
 
@@ -1587,7 +1588,6 @@ void ASTDeclReader::ReadCXXDefinitionData(
   Data.HasIrrelevantDestructor = Record.readInt();
   Data.HasConstexprNonCopyMoveConstructor = Record.readInt();
   Data.HasDefaultedDefaultConstructor = Record.readInt();
-  Data.CanPassInRegisters = Record.readInt();
   Data.DefaultedDefaultConstructorIsConstexpr = Record.readInt();
   Data.HasConstexprDefaultConstructor = Record.readInt();
   Data.HasNonLiteralTypeFieldsOrBases = Record.readInt();
@@ -1727,7 +1727,6 @@ void ASTDeclReader::MergeDefinitionData(
   MATCH_FIELD(HasIrrelevantDestructor)
   OR_FIELD(HasConstexprNonCopyMoveConstructor)
   OR_FIELD(HasDefaultedDefaultConstructor)
-  MATCH_FIELD(CanPassInRegisters)
   MATCH_FIELD(DefaultedDefaultConstructorIsConstexpr)
   OR_FIELD(HasConstexprDefaultConstructor)
   MATCH_FIELD(HasNonLiteralTypeFieldsOrBases)
@@ -4107,6 +4106,7 @@ void ASTDeclReader::UpdateDecl(Decl *D,
       bool HadRealDefinition =
           OldDD && (OldDD->Definition != RD ||
                     !Reader.PendingFakeDefinitionData.count(OldDD));
+      RD->setCanPassInRegisters(Record.readInt());
       ReadCXXRecordDefinition(RD, /*Update*/true);
 
       // Visible update is handled separately.