Call objc_retainBlock before passing a block as a variadic argument

Copy the block to the heap before passing it to the callee in case the
block escapes in the callee.

rdar://problem/55683462

Differential Revision: https://reviews.llvm.org/D71431

1 files changed, 3 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 620ec30b128..36eef4f425e 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -5247,6 +5247,9 @@ bool Sema::GatherArgumentsForCall(SourceLocation CallLoc, FunctionDecl *FDecl,
       for (Expr *A : Args.slice(ArgIx)) {
         ExprResult Arg = DefaultVariadicArgumentPromotion(A, CallType, FDecl);
         Invalid |= Arg.isInvalid();
+        // Copy blocks to the heap.
+        if (A->getType()->isBlockPointerType())
+          maybeExtendBlockObject(Arg);
         AllArgs.push_back(Arg.get());
       }
     }