Re: [PATCH] ipa: Implement a summary for callback edges

Hi,

On Tue, Aug 11 2026, Josef Melcr wrote:
> Hi,
> I rebased the patch and made these adjustments:
>  - I split the enum callback_position into enums callback_position and
>    arg_mapping_constants, as I do want to use an identifier
>    (ARG_MAPPING_UNKNOWN_IDX) instead of just -1.  I also replaced the
>    uses of -1 with said identifier.
>  - I changed where the summary is initialized.  Previously, it was
>    initialized in init_callback_edge_summary, but that function no
>    longer exists.  I moved the initialization into a method on the
>    summary itself and call it in cgraph_edge::make_callback.
>    - That might seem a bit odd, but I think that's the best way to do it, as
>      initializing in other places has problems (the summary is needed in
>      the duplication hooks, so it must be created before calling them.
>      However, there is no edge to associate the summary with before
>      calling make_callback, so it cannot be done before that without
>      changing the hooks as well).
>
> I am sending the patch for a last once-over just to be sure. I bootstrapped
> and retested the patch on x86_64-linux without issues.
>
> OK for master?

Yes, thanks a lot.

Martin

>
> Best regards,
> Josef
>
> gcc/ChangeLog:
>
> 	* Makefile.in: Add callback-info.o to OBJS.
> 	* attr-callback.cc (callback_fetch_attr_by_edge): Use fn_idx
> 	from the summary.
> 	(callback_get_arg_mapping): Replaced by
> 	callback_get_arg_mapping_from_attr and the summary field.
> 	(callback_get_arg_mapping_from_attr): New function, parses the
> 	attr and returns the computed argument mapping.
> 	(callback_fetch_fn_position): Delete, obsoleted by the summary.
> 	(callback_edge_useful_p): Check for the redirected flag in the
> 	summary instead of cgraph_node fields.
> 	* attr-callback.h (enum callback_position): Add comment.
> 	(enum arg_mapping_constants): New enum, defines the identifier
> 	for -1 in the arg_mapping vector.
> 	(callback_get_arg_mapping): Delete.
> 	(callback_fetch_fn_position): Delete.
> 	(callback_get_arg_mapping_from_attr): Add decl.
> 	* cgraph.cc (symbol_table::create_edge): Remove callback_id initializer.
> 	(cgraph_edge::make_callback): Initialize the callback_info
> 	summary, add necessary arguments.
> 	(cgraph_edge::redirect_callee): Set the redirected flag when
> 	redirecting a callback edge.
> 	(cgraph_edge::redirect_call_stmt_to_callee): Use the summary.
> 	(cgraph_node::verify_node): Remove callback_id checks.
> 	(cgraph_cc_finalize): Free the summaries.
> 	* cgraph.h: Remove callback_id from cgraph_edge, adjust decl of
> 	cgraph_edge::make_callback.
> 	* cgraphclones.cc (cgraph_edge::clone): Remove callback_id.
> 	* ipa-cp.cc (ipcp_driver): Initialize the summary sum.
> 	* ipa-prop.cc (ipa_compute_jump_functions_for_edge): Remove
> 	callback_id, adjust call to make_callback, use the summary.
> 	(ipa_analyze_node): Initialize the summary sum.
> 	(ipa_register_cgraph_hooks): Likewise.
> 	* lto-cgraph.cc (lto_output_edge): Remove callback_id, stream
> 	out the summary.
> 	(output_symtab): Initialize the summary sum.
> 	(input_edge): Remove callback_id, stream in the summary.
> 	(input_cgraph_1): Initialize the summary sum.
> 	* callback-info.cc: New file.
> 	* callback-info.h: New file.
>
> Signed-off-by: Josef Melcr <[email protected]>
> ---