[cfe-commits] [patch] Fix crash when referring from a closure to an enclosing local in a function returning void

[John McCall]

On Jul 11, 2012, at 8:35 AM, Nico Weber wrote:
> the attached patch fixes PR13314, clang crashing on code like this:
> 
> void f() {
>  Foo foo;
>  [=]() {
>    return foo;
>  };
> }
> 
> This crash was introduced in r152491, which replaced BlockDeclRefExpr
> with a bit on DeclRefExpr. getCopyElisionCandidate() wasn't taught
> about the new bit, so the the `return foo;` in the closure marks `foo`
> as a NRVO candidate, but codegen for f() then looks at the return type
> of f for NRVO. Since the function returns void, this results in a
> failing assert somewhere down the line (see the bug for more details).
> The attached patch makes getCopyElisionCandidate() ignore DeclRefExprs
> that return to enclosing locals, which is I believe what happened
> before r152491 too.
> 
> Ok?

Looks good, thanks!

John.