[PATCH] D87470: [Coroutine][Sema] Tighten the lifetime of symmetric transfer returned handle

[Xun Li via Phabricator via cfe-commits]

lxfind created this revision.
lxfind added reviewers: lewissbaker, wenlei, hoy, bruno, junparser, rjmccall.
Herald added subscribers: cfe-commits, dexonsmith, modocache.
Herald added a project: clang.
lxfind requested review of this revision.

In generating the code for symmetric transfer, a temporary object is created to store the returned handle from await_suspend() call of the awaiter. Previously this temp won't be cleaned up until very later, which ends up causing this temp to be spilled to the heap. However, we know that this temp will no longer be needed after the coro_resume call. We can clean it up right after.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D87470

Files:
  clang/lib/Sema/SemaCoroutine.cpp


Index: clang/lib/Sema/SemaCoroutine.cpp
===================================================================
--- clang/lib/Sema/SemaCoroutine.cpp
+++ clang/lib/Sema/SemaCoroutine.cpp
@@ -398,8 +398,8 @@
            diag::warn_coroutine_handle_address_invalid_return_type)
         << JustAddress->getType();
 
-  return buildBuiltinCall(S, Loc, Builtin::BI__builtin_coro_resume,
-                          JustAddress);
+  return S.MaybeCreateExprWithCleanups(
+      buildBuiltinCall(S, Loc, Builtin::BI__builtin_coro_resume, JustAddress));
 }
 
 /// Build calls to await_ready, await_suspend, and await_resume for a co_await


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