https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103328
--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
The first stmt we complain on remains in the same function. The functions
scope tree at the point of complaint is
{ Scope block #0
{ Scope block #0 (unused)
struct coroutine_handle _Coro_actor_continue;
{ Scope block #0 (unused)
void (*<Te0e>) (struct
_ZZZNSt11server_impl12send_messageISt7variantIJN12_GLOBAL__N_114append_requestEEEEEvNS2_8internal9tagged_idINS2_13server_id_tagEEET_ENKUlS9_E_clIS3_EEDaS9_ENKUlvE_clEv.Frame
*) _Coro_resume_fn [value-expr: frame_ptr->_Coro_resume_fn];
void (*<Te0e>) (struct
_ZZZNSt11server_impl12send_messageISt7variantIJN12_GLOBAL__N_114append_requestEEEEEvNS2_8internal9tagged_idINS2_13server_id_tagEEET_ENKUlS9_E_clIS3_EEDaS9_ENKUlvE_clEv.Frame
*) _Coro_destroy_fn [value-expr: frame_ptr->_Coro_destroy_fn];
struct promise_type _Coro_promise [value-expr: frame_ptr->_Coro_promise];
struct coroutine_handle _Coro_self_handle [value-expr:
frame_ptr->_Coro_self_handle];
const struct ._anon_5 * const __closure [value-expr:
frame_ptr->__closure];
short unsigned int _Coro_resume_index [value-expr:
frame_ptr->_Coro_resume_index];
bool _Coro_frame_needs_free [value-expr:
frame_ptr->_Coro_frame_needs_free];
bool _Coro_initial_await_resume_called [value-expr:
frame_ptr->_Coro_initial_await_resume_called];
{ Scope block #0 (unused)
struct suspend_never Is [value-expr: frame_ptr->Is_1_1];
}
{ Scope block #0
void resume.6 = <<< error >>>;
void destroy.6 = <<< error >>>;
void resume.4 = <<< error >>>;
void destroy.4 = <<< error >>>;
void resume.2 = <<< error >>>;
void destroy.2 = <<< error >>>;
void coro.delete.frame = <<< error >>>;
void coro.delete.promise = <<< error >>>;
void actor.continue.ret = <<< error >>>;
void actor.suspend.ret = <<< error >>>;
void actor.begin = <<< error >>>;
void final.suspend = <<< error >>>;
const struct tagged_id cid [value-expr: __closure->__cid];
const struct append_request cm [value-expr: __closure->__cm];
struct server_impl * const this [value-expr: __closure->__this];
{ Scope block #0 (unused)
struct
_ZZZNSt11server_impl12send_messageISt7variantIJN12_GLOBAL__N_114append_requestEEEEEvNS2_8internal9tagged_idINS2_13server_id_tagEEET_ENKUlS9_E_clIS3_EEDaS9_ENKUlvE_clEv.Frame
* _Coro_frameptr;
bool _Coro_promise_live;
bool _Coro_gro_live;
{ Scope block #0 (unused)
}
}
}
}
}
}
while at the point we lower control flow and set gimple_block it is
{ Scope block #0
{ Scope block #0 (unused)
struct coroutine_handle _Coro_actor_continue;
{ Scope block #0 (unused)
void (*<Te0e>) (struct
_ZZZNSt11server_impl12send_messageISt7variantIJN12_GLOBAL__N_114append_requestEEEEEvNS2_8internal9tagged_idINS2_13server_id_tagEEET_ENKUlS9_E_clIS3_EEDaS9_ENKUlvE_clEv.Frame
*) _Coro_resume_fn [value-expr: frame_ptr->_Coro_resume_fn];
void (*<Te0e>) (struct
_ZZZNSt11server_impl12send_messageISt7variantIJN12_GLOBAL__N_114append_requestEEEEEvNS2_8internal9tagged_idINS2_13server_id_tagEEET_ENKUlS9_E_clIS3_EEDaS9_ENKUlvE_clEv.Frame
*) _Coro_destroy_fn [value-expr: frame_ptr->_Coro_destroy_fn];
struct promise_type _Coro_promise [value-expr: frame_ptr->_Coro_promise];
struct coroutine_handle _Coro_self_handle [value-expr:
frame_ptr->_Coro_self_handle];
const struct ._anon_5 * const __closure [value-expr:
frame_ptr->__closure];
short unsigned int _Coro_resume_index [value-expr:
frame_ptr->_Coro_resume_index];
bool _Coro_frame_needs_free [value-expr:
frame_ptr->_Coro_frame_needs_free];
bool _Coro_initial_await_resume_called [value-expr:
frame_ptr->_Coro_initial_await_resume_called];
{ Scope block #0
void resume.6 = <<< error >>>;
void destroy.6 = <<< error >>>;
void resume.4 = <<< error >>>;
void destroy.4 = <<< error >>>;
void resume.2 = <<< error >>>;
void destroy.2 = <<< error >>>;
void coro.delete.frame = <<< error >>>;
void coro.delete.promise = <<< error >>>;
void actor.continue.ret = <<< error >>>;
void actor.suspend.ret = <<< error >>>;
void actor.begin = <<< error >>>;
void final.suspend = <<< error >>>;
const struct tagged_id cid [value-expr: __closure->__cid];
const struct append_request cm [value-expr: __closure->__cm];
struct server_impl * const this [value-expr: __closure->__this];
{ Scope block #0
struct append_request m [value-expr: frame_ptr->m_2_3];
struct tagged_id id [value-expr: frame_ptr->id_2_3];
{ Scope block #0 (unused)
struct awaiter Aw0 [value-expr: frame_ptr->Aw0_3_4];
}
}
}
{ Scope block #0 (unused)
struct suspend_never Is [value-expr: frame_ptr->Is_1_1];
}
}
}
}
The block we associate with the stmt is
{ Scope block #0 (unused)
struct awaiter Aw0 [value-expr: frame_ptr->Aw0_3_4];
}
it looks like there's mangling of the block tree happening somehow.
We run into
/* Lower a bind_expr TSI. DATA is passed through the recursion. */
static void
lower_gimple_bind (gimple_stmt_iterator *gsi, struct lower_data *data)
{
tree old_block = data->block;
gbind *stmt = as_a <gbind *> (gsi_stmt (*gsi));
tree new_block = gimple_bind_block (stmt);
if (new_block)
{
if (new_block == old_block)
{
/* The outermost block of the original function may not be the
outermost statement chain of the gimplified function. So we
may see the outermost block just inside the function. */
gcc_assert (new_block == DECL_INITIAL (current_function_decl));
new_block = NULL;
}
else
{
/* We do not expect to handle duplicate blocks. */
gcc_assert (!TREE_ASM_WRITTEN (new_block));
TREE_ASM_WRITTEN (new_block) = 1;
/* Block tree may get clobbered by inlining. Normally this would
be fixed in rest_of_decl_compilation using block notes, but
since we are not going to emit them, it is up to us. */
BLOCK_CHAIN (new_block) = BLOCK_SUBBLOCKS (old_block);
BLOCK_SUBBLOCKS (old_block) = new_block;
BLOCK_SUBBLOCKS (new_block) = NULL_TREE;
BLOCK_SUPERCONTEXT (new_block) = old_block;
with BLOCK_CHAIN (new_block) != NULL and lose those blocks. old_block
is the outermost block here.
It looks like the BIND_EXPR nesting does not match the BLOCK tree nesting
and things go wrong from there. The IL looks like
{
[t.i:533:13] try
{
[t.i:533:13] {
struct
_ZZZNSt11server_impl12send_messageISt7variantIJN12_GLOBAL__N_114append_requestEEEEEvNS2_8internal9tagged_idINS2_13server_id_tagEEET_ENKUlS9_E_clIS3_EEDaS9_ENKUlvE_clEv.Frame
* _Coro_frameptr;
bool _Coro_promise_live;
bool _Coro_gro_live;
[t.i:533:13] _Coro_frameptr = 0B;
[t.i:533:13] _Coro_promise_live = 0;
[t.i:533:13] _Coro_gro_live = 0;
[t.i:533:13] _1 = .CO_FRAME (48, _Coro_frameptr);
[t.i:533:13] _Coro_frameptr = operator new (_1);
[t.i:533:13] try
{
[t.i:533:13] [t.i:533:13] _Coro_frameptr->_Coro_frame_needs_free =
1;
[t.i:533:13] [t.i:533:13] _Coro_frameptr->_Coro_resume_fn =
operator();
[t.i:533:13] [t.i:533:13] _Coro_frameptr->_Coro_destroy_fn =
operator();
[t.i:533:13] [t.i:533:13] _Coro_frameptr->__closure = __closure;
[t.i:533:13] {
[t.i:533:13] _2 = [t.i:533:13] &[t.i:533:13]
_Coro_frameptr->_Coro_promise;
[t.i:533:13]
seastar::internal::coroutine_traits_base<>::promise_type::get_return_object
(_2);
[t.i:533:13] [t.i:533:13] _Coro_frameptr->_Coro_resume_index = 0;
[t.i:533:13]
std::server_impl::send_message<std::variant<{anonymous}::append_request>
>({anonymous}::server_id,
std::variant<{anonymous}::append_request>)::<lambda(auto:1)>::<lambda()>::operator()
(_Coro_frameptr);
[t.i:533:13] return <retval>;
}
}
catch
{
[t.i:533:13] catch (NULL)
{
[t.i:533:13] try
{
[t.i:533:13] _3 = __builtin_eh_pointer (0);
[t.i:533:13] __cxa_begin_catch (_3);
[t.i:533:13] operator delete (_Coro_frameptr);
[t.i:533:13] __cxa_rethrow ();
}
finally
{
[t.i:533:13] __cxa_end_catch ();
}
}
}
}
}
catch
{
<<<eh_must_not_throw (terminate)>>>
}
}
IIRC there's no "verification" of IL BIND_EXPR/gimple_block nesting vs.
DECL_INITIAL block tree nesting.
