[ObjC] Enter a new evaluation context before calling

BuildBlockForLambdaConversion.

Previously, clang would build an incorrect AST for the following code:

id test() {
  return @{@"a": [](){}, @"b": [](){}};
}

ReturnStmt 0x10d080448
`-ExprWithCleanups 0x10d080428
  |-cleanup Block 0x10d0801f0 // points to the second BlockDecl
    ...
    -BlockDecl 0x10d07f150 // First block
    ...
    -BlockDecl 0x10d0801f0 // Second block
    ...
     `-ExprWithCleanups 0x10d0801d0
       |-cleanup Block 0x10d07f150 // points to the first BlockDecl

To fix the bug, this commit enters a new evaluation context to reset
ExprNeedsCleanups before each block is parsed.

rdar://problem/16879958

Differential Revision: http://reviews.llvm.org/D18815

llvm-svn: 268527

1 files changed, 3 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 88f2bc798a2..e11d9c84fea 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -6229,9 +6229,12 @@ ExprResult Sema::BuildCXXMemberCallExpr(Expr *E, NamedDecl *FoundDecl,
       // follows the normal lifetime rules for block literals instead of being
       // autoreleased.
       DiagnosticErrorTrap Trap(Diags);
+      PushExpressionEvaluationContext(PotentiallyEvaluated);
       ExprResult Exp = BuildBlockForLambdaConversion(E->getExprLoc(),
                                                      E->getExprLoc(),
                                                      Method, E);
+      PopExpressionEvaluationContext();
+
       if (Exp.isInvalid())
         Diag(E->getExprLoc(), diag::note_lambda_to_block_conv);
       return Exp;