Ping.
Thx,
Martin
On Fri, Nov 21, 2014 at 08:18:12PM +0100, Martin Jambor wrote:
> Hi,
>
> when debugging PR 63814 I noticed that when cgraph_node::create_clone
> was using redirect_edge_duplicating_thunks to redirect two edges to a
> thunk of a clone, two thunks were created, one for each edge. The
> reason is that even though duplicate_thunk_for_node attempts to locate
> an already created thunk, it does so by looking for a caller with
> thunk.thunk_p set and the previously created one does not have it set
> because (on i686) expand_thunk has expanded the thunk to gimple and
> cleared the flag.
>
> This patch fixes the issue by marking such expanded thunks with yet
> another flag and then uses the flag to identify such expanded thunks.
> Bootstrapped and tested on x86_64-linux and i686-linux. Honza, do you
> think this is a good approach? Is the patch OK for trunk?
>
> Thanks,
>
> Martin
>
>
> 2014-11-21 Martin Jambor <mjam...@suse.cz>
>
> * cgraph.h (cgraph_thunk_info): Converted thunk_p to a bit-field.
> Added new flag expanded_thunk_p.
> * cgraphunit.c (expand_thunk): Set expanded_thunk_p when appropriate.
> * cgraphclones.c (duplicate_thunk_for_node): Also re-use an expanded
> thunk if available.
>
> Index: src/gcc/cgraph.h
> ===================================================================
> --- src.orig/gcc/cgraph.h
> +++ src/gcc/cgraph.h
> @@ -552,7 +552,9 @@ struct GTY(()) cgraph_thunk_info {
> bool virtual_offset_p;
> bool add_pointer_bounds_args;
> /* Set to true when alias node is thunk. */
> - bool thunk_p;
> + unsigned thunk_p : 1;
> + /* Set when this is an already expanded thunk. */
> + unsigned expanded_thunk_p : 1;
> };
>
> /* Information about the function collected locally.
> Index: src/gcc/cgraphclones.c
> ===================================================================
> --- src.orig/gcc/cgraphclones.c
> +++ src/gcc/cgraphclones.c
> @@ -311,7 +311,7 @@ duplicate_thunk_for_node (cgraph_node *t
>
> cgraph_edge *cs;
> for (cs = node->callers; cs; cs = cs->next_caller)
> - if (cs->caller->thunk.thunk_p
> + if ((cs->caller->thunk.thunk_p || cs->caller->thunk.expanded_thunk_p)
> && cs->caller->thunk.this_adjusting == thunk->thunk.this_adjusting
> && cs->caller->thunk.fixed_offset == thunk->thunk.fixed_offset
> && cs->caller->thunk.virtual_offset_p == thunk->thunk.virtual_offset_p
> Index: src/gcc/cgraphunit.c
> ===================================================================
> --- src.orig/gcc/cgraphunit.c
> +++ src/gcc/cgraphunit.c
> @@ -1504,6 +1504,7 @@ cgraph_node::expand_thunk (bool output_a
> set_cfun (NULL);
> TREE_ASM_WRITTEN (thunk_fndecl) = 1;
> thunk.thunk_p = false;
> + thunk.expanded_thunk_p = true;
> analyzed = false;
> }
> else
> @@ -1686,6 +1687,7 @@ cgraph_node::expand_thunk (bool output_a
> /* Since we want to emit the thunk, we explicitly mark its name as
> referenced. */
> thunk.thunk_p = false;
> + thunk.expanded_thunk_p = true;
> lowered = true;
> bitmap_obstack_release (NULL);
> }
