Hello everybody, currently this makes the virtual thunks and the virtual C++ base classes pretty much broken.
So it would be really nice if some one would like to review this patch. I attached the patch again, for your convenience. Thanks Bernd. ---------------------------------------- > From: bernd.edlin...@hotmail.de > To: gcc-patches@gcc.gnu.org > CC: richard.guent...@gmail.com; hubi...@ucw.cz > Subject: RE: [PING**3] [PATCH] Fix PR ipa/61190, 2nd edition > Date: Wed, 12 Nov 2014 13:43:18 +0100 > > > > Ping... > > > ---------------------------------------- >> From: bernd.edlin...@hotmail.de >> To: gcc-patches@gcc.gnu.org >> CC: richard.guent...@gmail.com; hubi...@ucw.cz >> Subject: RE: [PING**2] [PATCH] Fix PR ipa/61190, 2nd edition >> Date: Mon, 27 Oct 2014 09:23:41 +0100 >> >> >> Ping again... >> >> Thanks. >> >> ---------------------------------------- >>> From: bernd.edlin...@hotmail.de >>> To: hubi...@ucw.cz >>> CC: gcc-patches@gcc.gnu.org; richard.guent...@gmail.com >>> Subject: [PING] [PATCH] Fix PR ipa/61190, 2nd edition >>> Date: Tue, 14 Oct 2014 11:40:56 +0200 >>> >>> Ping... >>> >>> see: https://gcc.gnu.org/ml/gcc-patches/2014-10/msg00536.html >>> >>>> Hi Honza, >>>> >>>> >>>> as you know, we have a wrong code bug, when a pure or const method is >>>> called via a virtual thunk. >>>> I had some more Ideas, how to fix that, but all of them had some serious >>>> draw-backs, so I leave the details out... >>>> >>>> >>>> But now I have a new insight, why the "obvious" fix for this serious code >>>> generation bug did not work >>>> in the first place. >>>> >>>> >>>> And the reason was, that if ipa-pure-const.c calls set_const_flag or >>>> set_pure_flag for a thunk, it calls the same >>>> function later for the called method, and this overwrites the flags of >>>> _all_ associated thunks and aliases. >>>> However that should at least not be done for virtual thunks, as these need >>>> to be IPA_NEITHER, even if >>>> the method itself has different attributes, that is because the assembler >>>> thunk accesses the vtable, while >>>> other thunks do not. >>>> >>>> >>>> So I re-factored set_const_flag and set_pure_flag to exclude the virtual >>>> thunks, taking care that other >>>> users of call_for_symbol_thunks_and_aliases do not get a different >>>> behavior than before this patch. >>>> >>>> >>>> The attached patch was boot-strapped and >>>> regression-tested on x86_64-linux-gnu. >>>> Ok for trunk? >>>> >>>> >>>> PS: As a side-note, there are two identical functions, named >>>> "call_for_symbol_and_aliases", in >>>> class symtab_node and in class cgraph_node, which inherits from >>>> symtab_node. Both functions are >>>> not declared virtual. Is that what's intended? Usually this could lead to >>>> errors, or at least some serious >>>> compiler warnings. >>>> >>>> >>>> Thanks >>>> Bernd. >>>> >>> >> >
2014-10-07 Bernd Edlinger <bernd.edlin...@hotmail.de>
PR ipa/61190
* cgraph.h (symtab_node::call_for_symbol_and_aliases): Fix comment.
(cgraph_node::call_for_symbol_and_aliases): Likewise.
(cgraph_node::call_for_symbol_thunks_and_aliases_1): New function.
(cgraph_node::call_for_symbol_thunks_and_aliases): Adjust comment.
Call call_for_symbol_thunks_and_aliases_1.
* cgraph.c (cgraph_node::call_for_symbol_thunks_and_aliases): Renamed
to cgraph_node::call_for_symbol_thunks_and_aliases_1. Added new
parameter exclude_virtual_thunks.
(cgraph_node::set_const_flag): Don't propagate to virtual thunks.
(cgraph_node::set_pure_flag): Likewise.
* ipa-pure-const.c (analyze_function): For virtual thunks
set pure_const_state to IPA_NEITHER.
testsuite/ChangeLog:
2014-10-07 Bernd Edlinger <bernd.edlin...@hotmail.de>
PR ipa/61190
* g++.old-deja/g++.mike/p4736b.C: Use -O2.
patch-pr61190.diff
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