After talking to our runtime guru, I added a comment.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63141 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index eef7408..eb26a95 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -3562,6 +3562,11 @@
Field->getType().getTypePtr()) >> 3;
Align = llvm::Log2_32(Align);
Ivar[3] = llvm::ConstantInt::get(ObjCTypes.IntTy, Align);
+ // NOTE. Size of a bitfield does not match gcc's, because of the way
+ // bitfields are treated special in each. But I am told that 'size'
+ // for bitfield ivars is ignored by the runtime so it does not matter.
+ // (even if it matters, some day, there is enough info. to get the bitfield
+ // right!
Ivar[4] = llvm::ConstantInt::get(ObjCTypes.IntTy, Size);
Ivars.push_back(llvm::ConstantStruct::get(ObjCTypes.IvarnfABITy, Ivar));
}