>
> Currently a _lot_ of packages fail to build with LTO because LTO
> messes up fortify wrappers by replacing the call to the alias with
> the symbol itself, making the wrapper look like infinitely
> recursing.
>
> The following patch fixes this by dropping the bodies of
> DECL_EXTERN always-inline functions on the floor before IPA
> (and when doing LTO). IMHO we should at some point do this
> unconditional on LTO as the early inliner is supposed to
> remove all references to always-inline functions.
>
> I'm not 100% sure about the cgraph API use to drop the function
> body, but at least it seems to work ;) I'm not sure if we want
> to restrict the set of functions to apply this even more than
> just those with always-inline and DECL_EXTERNAL set?
>
> Now double-checking with a fortified LTO bootstrap.
>
> Ok for trunk?
>
> Thanks,
> Richard.
>
> 2014-03-24 Richard Biener <rguent...@suse.de>
>
> PR lto/59626
> * passes.c (ipa_write_summaries): Drop function bodies of
> extern always-inline functions.
I think it is probably better to drop these during unreachable function removal
same way as we drop extern inlines after inlining (just use cgraph_state check
to
see if we are past early inlining). I will make patch this afternoon.
Why do you need to remove the always_inline attribute? And how do I do fortified
LTO bootstrap? :)
Honza
>
> * gcc.dg/lto/pr59626_0.c: New testcase.
> * gcc.dg/lto/pr59626_1.c: Likewise.
>
> Index: gcc/passes.c
> ===================================================================
> *** gcc/passes.c (revision 208745)
> --- gcc/passes.c (working copy)
> *************** ipa_write_summaries (void)
> *** 2390,2404 ****
>
> if (cgraph_function_with_gimple_body_p (node))
> {
> ! /* When streaming out references to statements as part of some IPA
> ! pass summary, the statements need to have uids assigned and the
> ! following does that for all the IPA passes here. Naturally, this
> ! ordering then matches the one IPA-passes get in their stmt_fixup
> ! hooks. */
> !
> ! push_cfun (DECL_STRUCT_FUNCTION (node->decl));
> ! renumber_gimple_stmt_uids ();
> ! pop_cfun ();
> }
> if (node->definition)
> lto_set_symtab_encoder_in_partition (encoder, node);
> --- 2396,2427 ----
>
> if (cgraph_function_with_gimple_body_p (node))
> {
> ! if (DECL_EXTERNAL (node->decl)
> ! && lookup_attribute ("always_inline",
> ! DECL_ATTRIBUTES (node->decl)) != NULL)
> ! {
> ! /* We mess up uses of extern always-inline wrappers that
> ! end up calling an alias to itself like glibc _FORTIFY_SOURCE
> ! wrappers. Simply drop the bodies of the extern inlines
> ! here to avoid that. */
> ! cgraph_release_function_body (node);
> ! node->analyzed = false;
> ! node->definition = false;
> ! DECL_ATTRIBUTES (node->decl)
> ! = remove_attribute ("always_inline",
> ! DECL_ATTRIBUTES (node->decl));
> ! }
> ! else
> ! {
> ! /* When streaming out references to statements as part of some
> ! IPA pass summary, the statements need to have uids assigned
> ! and the following does that for all the IPA passes here.
> ! Naturally, this ordering then matches the one IPA-passes get
> ! in their stmt_fixup hooks. */
> ! push_cfun (DECL_STRUCT_FUNCTION (node->decl));
> ! renumber_gimple_stmt_uids ();
> ! pop_cfun ();
> ! }
> }
> if (node->definition)
> lto_set_symtab_encoder_in_partition (encoder, node);
> Index: gcc/testsuite/gcc.dg/lto/pr59626_0.c
> ===================================================================
> *** gcc/testsuite/gcc.dg/lto/pr59626_0.c (revision 0)
> --- gcc/testsuite/gcc.dg/lto/pr59626_0.c (working copy)
> ***************
> *** 0 ****
> --- 1,15 ----
> + /* { dg-lto-do run } */
> +
> + int __atoi (const char *) __asm__("atoi");
> + extern inline __attribute__((always_inline,gnu_inline))
> + int atoi (const char *x)
> + {
> + return __atoi (x);
> + }
> +
> + int bar (int (*)(const char *));
> +
> + int main()
> + {
> + return bar (atoi);
> + }
> Index: gcc/testsuite/gcc.dg/lto/pr59626_1.c
> ===================================================================
> *** gcc/testsuite/gcc.dg/lto/pr59626_1.c (revision 0)
> --- gcc/testsuite/gcc.dg/lto/pr59626_1.c (working copy)
> ***************
> *** 0 ****
> --- 1,4 ----
> + int bar (int (*fn)(const char *))
> + {
> + return fn ("0");
> + }
