From a961ad1b13b9c294d4565344912b8e35ba71b369 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Arsen=20Arsenovi=C4=87?= Date: Sun, 4 Sep 2022 21:04:23 +0200 Subject: c++: top level bind when rewriting coroutines [PR106188] MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In the edge case of a coroutine not containing any locals, the ifcd/switch temporaries would get added to the coroutine frame, corrupting its layout. To prevent this, we can make sure there is always a BIND_EXPR at the top of the function body, and thus, always a place for our new temporaries to go without interfering with the coroutine frame. PR c++/106188 - Incorrect frame layout after transforming conditional statement without top-level bind expression PR c++/106713 - if (co_await ...) crashes with a jump to ud2 PR c++/106188 PR c++/106713 gcc/cp/ChangeLog: * coroutines.cc (coro_rewrite_function_body): Ensure we have a BIND_EXPR wrapping the function body. gcc/testsuite/ChangeLog: * g++.dg/coroutines/pr106188.C: New test. Signed-off-by: Arsen Arsenović --- gcc/cp/coroutines.cc | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'gcc/cp') diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc index edb3b70..eca01ab 100644 --- a/gcc/cp/coroutines.cc +++ b/gcc/cp/coroutines.cc @@ -4095,6 +4095,15 @@ coro_rewrite_function_body (location_t fn_start, tree fnbody, tree orig, BLOCK_SUPERCONTEXT (replace_blk) = top_block; BLOCK_SUBBLOCKS (top_block) = replace_blk; } + else + { + /* We are missing a top level BIND_EXPR. We need one to ensure that we + don't shuffle around the coroutine frame and corrupt it. */ + tree bind_wrap = build3_loc (fn_start, BIND_EXPR, void_type_node, + NULL, NULL, NULL); + BIND_EXPR_BODY (bind_wrap) = fnbody; + fnbody = bind_wrap; + } /* Wrap the function body in a try {} catch (...) {} block, if exceptions are enabled. */ -- cgit v1.1