On 3/20/20 11:40 AM, Iain Sandoe via Gcc-patches wrote:
2020-03-20 Iain Sandoe <i...@sandoe.co.uk>
* coroutines.cc (coro_init_identifiers): Initialize an identifier
for the cororoutine handle 'address' method name.
(struct coro_aw_data): Add fields to cover the continuations.
(co_await_expander): Determine the kind of await_suspend in use.
If we have the case that returns a continuation handle, then save
this and make the target for 'scope exit without cleanup' be the
continuation resume label.
(expand_co_awaits): Handle the continuation case.
(struct suspend_point_info): Remove fields that kept the returned
await_suspend handle type.
(transform_await_expr): Remove code tracking continuation handles.
(build_actor_fn): Add the continuation handle as an actor-function
scope var. Build the symmetric transfer continuation point.
(register_await_info): Remove fields tracking continuation handles.
(get_await_suspend_return_type): Remove.
(register_awaits): Remove code tracking continuation handles.
(morph_fn_to_coro): Remove code tracking continuation handles.
gcc/testsuite/ChangeLog:
2020-03-20 Iain Sandoe <i...@sandoe.co.uk>
* g++.dg/coroutines/torture/co-ret-09-bool-await-susp.C: Amend
to n4849 behaviour.
* g++.dg/coroutines/torture/symmetric-transfer-00-basic.C: New
test.
diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index abd4cac1c82..49e03f2ccea 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
tree suspend = TREE_VEC_ELT (awaiter_calls, 1); /* await_suspend(). */
+ tree susp_type;
+ if (TREE_CODE (suspend) == CALL_EXPR)
+ {
+ susp_type = CALL_EXPR_FN (suspend);
+ if (TREE_CODE (susp_type) == ADDR_EXPR)
+ susp_type = TREE_OPERAND (susp_type, 0);
+ susp_type = TREE_TYPE (TREE_TYPE (susp_type));
+ }
+ else
+ susp_type = TREE_TYPE (suspend);
I think:
if (tree fndec = get_callee_fndecl_nofold (suspend))
susp_type = TREE_TYPE (TREE_TYPE (fndecl));
else
susp_type = TREE_TYPE (suspend);
would do? But how can TREE_TYPE (suspend) be different from the return
type of the function decl? It seems funky that the behaviour could
depend on the form of the suspend. What am I missing?
@@ -1532,6 +1553,8 @@ co_await_expander (tree *stmt, int * /*do_subtree*/, void
*d)
= build1 (ADDR_EXPR, build_reference_type (void_type_node), resume_label);
tree susp
= build1 (ADDR_EXPR, build_reference_type (void_type_node),
data->cororet);
+ tree cont
+ = build1 (ADDR_EXPR, build_reference_type (void_type_node),
data->corocont);
tree final_susp = build_int_cst (integer_type_node, is_final ? 1 : 0);
Wait, 'void &' is not a thing. What's been happening here? do you mean
to build pointer_types? 'build_address (data->$FIELD)'
@@ -2012,6 +2027,15 @@ build_actor_fn (location_t loc, tree coro_frame_type,
tree actor, tree fnbody,
= create_named_label_with_ctx (loc, "actor.begin", actor);
tree actor_frame = build1_loc (loc, INDIRECT_REF, coro_frame_type,
actor_fp);
+ /* Init the continuation with a NULL ptr. */
+ tree zeroinit = build1 (CONVERT_EXPR, void_coro_handle_type,
+ integer_zero_node);
+ tree ci = build2 (INIT_EXPR, void_coro_handle_type, continuation, zeroinit);
+ ci = build_stmt (loc, DECL_EXPR, continuation);
This appears to be overwriting ci?
+ ci = build1_loc (loc, CONVERT_EXPR, void_type_node, ci);
.. and still expecting it to be an EXPR node?
+ ci = maybe_cleanup_point_expr_void (ci);
+ add_stmt (ci);
+
/* Re-write param references in the body, no code should be generated
here. */
if (DECL_ARGUMENTS (orig))
+
+ /* Now we have the actual call, and we can mark it as a tail. */
+ CALL_EXPR_TAILCALL (resume) = true;
+ /* ... and for optimisation levels 0..1, mark it as requiring a tail-call
+ for correctness. It seems that doing this for optimisation levels that
+ normally perform tail-calling, confuses the ME (or it would be logical
+ to put this on unilaterally). */
Might be worth ping a ME expert about why that is?
+ if (optimize < 2)
+ CALL_EXPR_MUST_TAIL_CALL (resume) = true;
+ resume = coro_build_cvt_void_expr_stmt (resume, loc);
+ add_stmt (resume);
+
+ r = build_stmt (loc, RETURN_EXPR, NULL);
+ r = maybe_cleanup_point_expr_void (r);
Shouldn't there be no cleanups? Perhaps assert it didn't add any?
+ add_stmt (r);
+
/* We need the resume index to work with. */
tree res_idx_m
= lookup_member (coro_frame_type, resume_idx_name,
nathan
--
Nathan Sidwell
