Variable auto-init of blocks capturing self after init bugfix

Summary:
Blocks that capture themselves (and escape) after initialization currently codegen wrong because this:

  bool capturedByInit =
      Init && emission.IsEscapingByRef && isCapturedBy(D, Init);

  Address Loc =
      capturedByInit ? emission.Addr : emission.getObjectAddress(*this);

Already adjusts Loc from thr alloca to a GEP. This code:

    if (emission.IsEscapingByRef)
      Loc = emitBlockByrefAddress(Loc, &D, /*follow=*/false);

Was trying to do the same adjustment, and a GEP on a GEP (returning an int) triggers an assertion.

<rdar://problem/47943027>

Reviewers: ahatanak

Subscribers: jkorous, dexonsmith, cfe-commits, rjmccall

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58218

llvm-svn: 354147
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 2ac3de9..6c8b27a 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -1620,8 +1620,9 @@
   bool capturedByInit =
       Init && emission.IsEscapingByRef && isCapturedBy(D, Init);
 
-  Address Loc =
-      capturedByInit ? emission.Addr : emission.getObjectAddress(*this);
+  bool locIsByrefHeader = !capturedByInit;
+  const Address Loc =
+      locIsByrefHeader ? emission.getObjectAddress(*this) : emission.Addr;
 
   // Note: constexpr already initializes everything correctly.
   LangOptions::TrivialAutoVarInitKind trivialAutoVarInit =
@@ -1637,7 +1638,7 @@
       return;
 
     // Only initialize a __block's storage: we always initialize the header.
-    if (emission.IsEscapingByRef)
+    if (emission.IsEscapingByRef && !locIsByrefHeader)
       Loc = emitBlockByrefAddress(Loc, &D, /*follow=*/false);
 
     CharUnits Size = getContext().getTypeSizeInChars(type);
@@ -1744,10 +1745,9 @@
   }
 
   llvm::Type *BP = CGM.Int8Ty->getPointerTo(Loc.getAddressSpace());
-  if (Loc.getType() != BP)
-    Loc = Builder.CreateBitCast(Loc, BP);
-
-  emitStoresForConstant(CGM, D, Loc, isVolatile, Builder, constant);
+  emitStoresForConstant(
+      CGM, D, (Loc.getType() == BP) ? Loc : Builder.CreateBitCast(Loc, BP),
+      isVolatile, Builder, constant);
 }
 
 /// Emit an expression as an initializer for an object (variable, field, etc.)