When converting a block pointer to an Objective-C pointer type, extend

the lifetime of the block by copying it to the heap, or else we'll get
a dangling reference because the code working with the non-block-typed
object will not know it needs to copy.

There is some danger here, e.g. with assigning a block literal to an
unsafe variable, but, well, it's an unsafe variable.

llvm-svn: 139451

1 files changed, 9 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 1d903379c01..b8b722503a6 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -2388,6 +2388,15 @@ Sema::PerformImplicitConversion(Expr *From, QualType ToType,
     CXXCastPath BasePath;
     if (CheckPointerConversion(From, ToType, Kind, BasePath, CStyle))
       return ExprError();
+
+    // Make sure we extend blocks if necessary.
+    // FIXME: doing this here is really ugly.
+    if (Kind == CK_BlockPointerToObjCPointerCast) {
+      ExprResult E = From;
+      (void) PrepareCastToObjCObjectPointer(E);
+      From = E.take();
+    }
+
     From = ImpCastExprToType(From, ToType, Kind, VK_RValue, &BasePath, CCK)
              .take();
     break;