On 12/11/15 13:15, Jan Hubicka wrote:
Jan,
b) augment can_replace_by_local_alias_in_vtable to check whether
aliases can be created?
I think this is best: can_replace_by_local_alias_in_vtable exists to prevent the
body walk in cases we are not going to create the alias. This is because in LTO
we may need to stream in the constructor from the object file that is not
copletely
free and thus it is better to not touch it unless necessary.
I went with augmenting can_replace_by_local_alias, which
can_replace_by_local_alias_in_vtable calls. I also noticed that both should be
static, which I suspect will encourage the inliner to go inline them and then
determine a bunch of code is unreachable.
tested on x86-linux and ptx-none.
ok?
nathan
2015-12-12 Nathan Sidwell <nat...@acm.org>
* ipa-visibility.c (can_replace_by_local_alias): Make static,
check ASM_OUTPUT_DEF.
(can_replace_by_local_alias_in_vtable): Make static.
(function_and_variable_visibility): Reformat overlong comment.
Index: ipa-visibility.c
===================================================================
--- ipa-visibility.c (revision 231571)
+++ ipa-visibility.c (working copy)
@@ -329,9 +329,13 @@ varpool_node::externally_visible_p (void
Local aliases save dynamic linking overhead and enable more optimizations.
*/
-bool
+static bool
can_replace_by_local_alias (symtab_node *node)
{
+#ifndef ASM_OUTPUT_DEF
+ /* If aliases aren't supported, we can't do replacement. */
+ return false;
+#endif
/* Weakrefs have a reason to be non-local. Be sure we do not replace
them. */
while (node->transparent_alias && node->definition && !node->weakref)
@@ -344,11 +348,11 @@ can_replace_by_local_alias (symtab_node
&& !node->can_be_discarded_p ());
}
-/* Return true if we can replace refernece to NODE by local alias
+/* Return true if we can replace reference to NODE by local alias
within a virtual table. Generally we can replace function pointers
and virtual table pointers. */
-bool
+static bool
can_replace_by_local_alias_in_vtable (symtab_node *node)
{
if (is_a <varpool_node *> (node)
@@ -592,10 +596,11 @@ function_and_variable_visibility (bool w
if (!node->local.local)
node->local.local |= node->local_p ();
- /* If we know that function can not be overwritten by a different semantics
- and moreover its section can not be discarded, replace all direct calls
- by calls to an noninterposable alias. This make dynamic linking
- cheaper and enable more optimization.
+ /* If we know that function can not be overwritten by a
+ different semantics and moreover its section can not be
+ discarded, replace all direct calls by calls to an
+ noninterposable alias. This make dynamic linking cheaper and
+ enable more optimization.
TODO: We can also update virtual tables. */
if (node->callers
