Block ivar layout must assume that the 'isa'
field of the block descriptor is GC'able (scanned)
as this what the runtime expects (one can send it
messages). Radar 8394947.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@113454 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 9bd1d66..8254135 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -1675,6 +1675,9 @@
unsigned WordSizeInBits = CGM.getContext().Target.getPointerWidth(0);
unsigned ByteSizeInBits = CGM.getContext().Target.getCharWidth();
+ // __isa is the first field in block descriptor and must assume by runtime's
+ // convention that it is GC'able.
+ IvarsInfo.push_back(GC_IVAR(0, 1));
for (size_t i = 0; i < DeclRefs.size(); ++i) {
const BlockDeclRefExpr *BDRE = DeclRefs[i];
const ValueDecl *VD = BDRE->getDecl();