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Date: Thu, 08 Mar 2012 21:00:00 -0000
Message-ID: <CAAkRFZKM8KXFYeFXi78bt8OmC6TAH+NZ-M6ULh_a-OLn96Lbzg@mail.gmail.com>
Subject: Re: User directed Function Multiversioning via Function Overloading (issue5752064)
From: Xinliang David Li <davidxl@google.com>
To: Richard Guenther <richard.guenther@gmail.com>
Cc: Sriraman Tallam <tmsriram@google.com>, reply@codereview.appspotmail.com, 	gcc-patches@gcc.gnu.org
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> You don't give an overview of the frontend implementation. =A0Thus I have
> extracted the following
>
> =A0- the FE does not really know about the "overloading", nor can it dire=
ctly
> =A0 resolve calls from a "sse" function to another "sse" function without=
 going
> =A0 through the 2nd IFUNC
>
> =A0- cgraph also does not know about the "overloading", so it cannot do s=
uch
> =A0 "devirtualization" either
>
> you seem to have implemented something inbetween a pure frontend
> solution and a proper middle-end solution. =A0For optimization and eventu=
ally
> automatically selecting functions for cloning (like, callees of a manual =
"sse"
> versioned function should be cloned?) it would be nice if the cgraph would
> know about the different versions and their relationships (and the dispat=
cher).
> Especially the cgraph code should know the functions are semantically
> equivalent (I suppose we should require that). =A0The IFUNC should be
> generated by cgraph / target code, similar to how we generate C++ thunks.

The implementation is very similar to the case when the user writes
its own ifunc and resolver. The difference here is that the
resolver/dispatcher is synthesized by the compiler.  Thunk is
different -- as it is completely user invisible.

Promoting ifunc to cgraph level has its advantage, but can also
introduce burdens to ipa passes as it has to be understood by them.

thanks,

David
>
> Honza, any suggestions on how the FE side of such cgraph infrastructure
> should look like and how we should encode the target bits?
>
> Thanks,
> Richard.
>
>> =A0 =A0 =A0 =A0* doc/tm.texi.in: Add description for TARGET_DISPATCH_VER=
SION.
>> =A0 =A0 =A0 =A0* doc/tm.texi: Regenerate.
>> =A0 =A0 =A0 =A0* c-family/c-common.c (handle_targetv_attribute): New fun=
ction.
>> =A0 =A0 =A0 =A0* target.def (dispatch_version): New target hook.
>> =A0 =A0 =A0 =A0* tree.h (DECL_FUNCTION_VERSIONED): New macro.
>> =A0 =A0 =A0 =A0(tree_function_decl): New bit-field versioned_function.
>> =A0 =A0 =A0 =A0* tree-pass.h (pass_dispatch_versions): New pass.
>> =A0 =A0 =A0 =A0* multiversion.c: New file.
>> =A0 =A0 =A0 =A0* multiversion.h: New file.
>> =A0 =A0 =A0 =A0* cgraphunit.c: Include multiversion.h
>> =A0 =A0 =A0 =A0(cgraph_finalize_function): Change assembler names of ver=
sioned
>> =A0 =A0 =A0 =A0functions.
>> =A0 =A0 =A0 =A0* cp/class.c: Include multiversion.h
>> =A0 =A0 =A0 =A0(add_method): aggregate function versions. Change assembl=
er names of
>> =A0 =A0 =A0 =A0versioned functions.
>> =A0 =A0 =A0 =A0(resolve_address_of_overloaded_function): Match address o=
f function
>> =A0 =A0 =A0 =A0version with default function. =A0Return address of ifunc=
 dispatcher
>> =A0 =A0 =A0 =A0for address of versioned functions.
>> =A0 =A0 =A0 =A0* cp/decl.c (decls_match): Make decls unmatched for versi=
oned
>> =A0 =A0 =A0 =A0functions.
>> =A0 =A0 =A0 =A0(duplicate_decls): Remove ambiguity for versioned functio=
ns. Notify
>> =A0 =A0 =A0 =A0of deleted function version decls.
>> =A0 =A0 =A0 =A0(start_decl): Change assembler name of versioned function=
s.
>> =A0 =A0 =A0 =A0(start_function): Change assembler name of versioned func=
tions.
>> =A0 =A0 =A0 =A0(cxx_comdat_group): Make comdat group of versioned functi=
ons be the
>> =A0 =A0 =A0 =A0same.
>> =A0 =A0 =A0 =A0* cp/semantics.c (expand_or_defer_fn_1): Mark as needed v=
ersioned
>> =A0 =A0 =A0 =A0functions that are also marked inline.
>> =A0 =A0 =A0 =A0* cp/decl2.c: Include multiversion.h
>> =A0 =A0 =A0 =A0(check_classfn): Check attributes of versioned functions =
for match.
>> =A0 =A0 =A0 =A0* cp/call.c: Include multiversion.h
>> =A0 =A0 =A0 =A0(build_over_call): Make calls to multiversioned functions=
 to call the
>> =A0 =A0 =A0 =A0dispatcher.
>> =A0 =A0 =A0 =A0(joust): For calls to multi-versioned functions, make the=
 default
>> =A0 =A0 =A0 =A0function win.
>> =A0 =A0 =A0 =A0* timevar.def (TV_MULTIVERSION_DISPATCH): New time var.
>> =A0 =A0 =A0 =A0* varasm.c (finish_aliases_1): Check if the alias points =
to a function
>> =A0 =A0 =A0 =A0with a body before giving an error.
>> =A0 =A0 =A0 =A0* Makefile.in: Add multiversion.o
>> =A0 =A0 =A0 =A0* passes.c: Add pass_dispatch_versions to the pass list.
>> =A0 =A0 =A0 =A0* config/i386/i386.c (add_condition_to_bb): New function.
>> =A0 =A0 =A0 =A0(get_builtin_code_for_version): New function.
>> =A0 =A0 =A0 =A0(ix86_dispatch_version): New function.
>> =A0 =A0 =A0 =A0(TARGET_DISPATCH_VERSION): New macro.
>> =A0 =A0 =A0 =A0* testsuite/g++.dg/mv1.C: New test.
>>
>> Index: doc/tm.texi
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- doc/tm.texi (revision 184971)
>> +++ doc/tm.texi (working copy)
>> @@ -10995,6 +10995,14 @@ The result is another tree containing a simplif=
ied
>> =A0call's result. =A0If @var{ignore} is true the value will be ignored.
>> =A0@end deftypefn
>>
>> +@deftypefn {Target Hook} int TARGET_DISPATCH_VERSION (tree @var{dispatc=
h_decl}, void *@var{fndecls}, basic_block *@var{empty_bb})
>> +For multi-versioned function, this hook sets up the dispatcher.
>> +@var{dispatch_decl} is the function that will be used to dispatch the
>> +version. @var{fndecls} are the function choices for dispatch.
>> +@var{empty_bb} is an basic block in @var{dispatch_decl} where the
>> +code to do the dispatch will be added.
>> +@end deftypefn
>> +
>> =A0@deftypefn {Target Hook} {const char *} TARGET_INVALID_WITHIN_DOLOOP =
(const_rtx @var{insn})
>>
>> =A0Take an instruction in @var{insn} and return NULL if it is valid with=
in a
>> Index: doc/tm.texi.in
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- doc/tm.texi.in =A0 =A0 =A0(revision 184971)
>> +++ doc/tm.texi.in =A0 =A0 =A0(working copy)
>> @@ -10873,6 +10873,14 @@ The result is another tree containing a simplif=
ied
>> =A0call's result. =A0If @var{ignore} is true the value will be ignored.
>> =A0@end deftypefn
>>
>> +@hook TARGET_DISPATCH_VERSION
>> +For multi-versioned function, this hook sets up the dispatcher.
>> +@var{dispatch_decl} is the function that will be used to dispatch the
>> +version. @var{fndecls} are the function choices for dispatch.
>> +@var{empty_bb} is an basic block in @var{dispatch_decl} where the
>> +code to do the dispatch will be added.
>> +@end deftypefn
>> +
>> =A0@hook TARGET_INVALID_WITHIN_DOLOOP
>>
>> =A0Take an instruction in @var{insn} and return NULL if it is valid with=
in a
>> Index: c-family/c-common.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- c-family/c-common.c (revision 184971)
>> +++ c-family/c-common.c (working copy)
>> @@ -315,6 +315,7 @@ static tree check_case_value (tree);
>> =A0static bool check_case_bounds (tree, tree, tree *, tree *);
>>
>> =A0static tree handle_packed_attribute (tree *, tree, tree, int, bool *);
>> +static tree handle_targetv_attribute (tree *, tree, tree, int, bool *);
>> =A0static tree handle_nocommon_attribute (tree *, tree, tree, int, bool =
*);
>> =A0static tree handle_common_attribute (tree *, tree, tree, int, bool *);
>> =A0static tree handle_noreturn_attribute (tree *, tree, tree, int, bool =
*);
>> @@ -604,6 +605,8 @@ const struct attribute_spec c_common_attribute_tab
>> =A0{
>> =A0 /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handle=
r,
>> =A0 =A0 =A0 =A0affects_type_identity } */
>> + =A0{ "targetv", =A0 =A0 =A0 =A0 =A0 =A0 =A0 1, -1, true, false, false,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 handle_targetv=
_attribute, false },
>> =A0 { "packed", =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 0, 0, false, false, fals=
e,
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0handle_packed=
_attribute , false},
>> =A0 { "nocommon", =A0 =A0 =A0 =A0 =A0 =A0 =A0 0, 0, true, =A0false, fals=
e,
>> @@ -5869,6 +5872,54 @@ handle_packed_attribute (tree *node, tree name, tr
>> =A0 return NULL_TREE;
>> =A0}
>>
>> +/* The targetv attribue is used to specify a function version
>> + =A0 targeted to specific platform types. =A0The "targetv" attributes
>> + =A0 have to be valid "target" attributes. =A0NODE should always point
>> + =A0 to a FUNCTION_DECL. =A0ARGS contain the arguments to "targetv"
>> + =A0 which should be valid arguments to attribute "target" too.
>> + =A0 Check handle_target_attribute for FLAGS and NO_ADD_ATTRS. =A0*/
>> +
>> +static tree
>> +handle_targetv_attribute (tree *node, tree name,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 tree args,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 int flags,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 bool *no_add_attrs)
>> +{
>> + =A0const char *attr_str =3D NULL;
>> + =A0gcc_assert (TREE_CODE (*node) =3D=3D FUNCTION_DECL);
>> + =A0gcc_assert (args !=3D NULL);
>> +
>> + =A0/* This is a function version. =A0*/
>> + =A0DECL_FUNCTION_VERSIONED (*node) =3D 1;
>> +
>> + =A0attr_str =3D TREE_STRING_POINTER (TREE_VALUE (args));
>> +
>> + =A0/* Check if multiple sets of target attributes are there. =A0This
>> + =A0 =A0 is not supported now. =A0 In future, this will be supported by
>> + =A0 =A0 cloning this function for each set. =A0*/
>> + =A0if (TREE_CHAIN (args) !=3D NULL)
>> + =A0 =A0warning (OPT_Wattributes, "%qE attribute has multiple sets whic=
h "
>> + =A0 =A0 =A0 =A0 =A0 =A0"is not supported", name);
>> +
>> + =A0if (attr_str =3D=3D NULL
>> + =A0 =A0 =A0|| strstr (attr_str, "arch=3D") =3D=3D NULL)
>> + =A0 =A0error_at (DECL_SOURCE_LOCATION (*node),
>> + =A0 =A0 =A0 =A0 =A0 =A0 "Versioning supported only on \"arch=3D\" for =
now");
>> +
>> + =A0/* targetv attributes must translate into target attributes. =A0*/
>> + =A0handle_target_attribute (node, get_identifier ("target"), args, fla=
gs,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0no_add_attrs);
>> +
>> + =A0if (*no_add_attrs)
>> + =A0 =A0warning (OPT_Wattributes, "%qE attribute has no effect", name);
>> +
>> + =A0/* This is necessary to keep the attribute tagged to the decl
>> + =A0 =A0 all the time. =A0*/
>> + =A0*no_add_attrs =3D false;
>> +
>> + =A0return NULL_TREE;
>> +}
>> +
>> =A0/* Handle a "nocommon" attribute; arguments as in
>> =A0 =A0struct attribute_spec.handler. =A0*/
>>
>> Index: target.def
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- target.def =A0(revision 184971)
>> +++ target.def =A0(working copy)
>> @@ -1249,6 +1249,15 @@ DEFHOOK
>> =A0tree, (tree fndecl, int n_args, tree *argp, bool ignore),
>> =A0hook_tree_tree_int_treep_bool_null)
>>
>> +/* Target hook to generate the dispatching code for calls to multi-vers=
ioned
>> + =A0 functions. =A0DISPATCH_DECL is the function that will have the dis=
patching
>> + =A0 logic. =A0FNDECLS are the list of choices for dispatch and EMPTY_B=
B is the
>> + =A0 basic bloc in DISPATCH_DECL which will contain the code. =A0*/
>> +DEFHOOK
>> +(dispatch_version,
>> + "",
>> + int, (tree dispatch_decl, void *fndecls, basic_block *empty_bb), NULL)
>> +
>> =A0/* Returns a code for a target-specific builtin that implements
>> =A0 =A0reciprocal of the function, or NULL_TREE if not available. =A0*/
>> =A0DEFHOOK
>> Index: tree.h
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- tree.h =A0 =A0 =A0(revision 184971)
>> +++ tree.h =A0 =A0 =A0(working copy)
>> @@ -3532,6 +3532,12 @@ extern VEC(tree, gc) **decl_debug_args_insert (tre
>> =A0#define DECL_FUNCTION_SPECIFIC_OPTIMIZATION(NODE) \
>> =A0 =A0(FUNCTION_DECL_CHECK (NODE)->function_decl.function_specific_opti=
mization)
>>
>> +/* In FUNCTION_DECL, this is set if this function has other versions ge=
nerated
>> + =A0 using "targetv" attributes. =A0The default version is the one whic=
h does not
>> + =A0 have any "targetv" attribute set. */
>> +#define DECL_FUNCTION_VERSIONED(NODE)\
>> + =A0 (FUNCTION_DECL_CHECK (NODE)->function_decl.versioned_function)
>> +
>> =A0/* FUNCTION_DECL inherits from DECL_NON_COMMON because of the use of =
the
>> =A0 =A0arguments/result/saved_tree fields by front ends. =A0 It was eith=
er inherit
>> =A0 =A0FUNCTION_DECL from non_common, or inherit non_common from FUNCTIO=
N_DECL,
>> @@ -3576,8 +3582,8 @@ struct GTY(()) tree_function_decl {
>> =A0 unsigned looping_const_or_pure_flag : 1;
>> =A0 unsigned has_debug_args_flag : 1;
>> =A0 unsigned tm_clone_flag : 1;
>> -
>> - =A0/* 1 bit left */
>> + =A0unsigned versioned_function : 1;
>> + =A0/* No bits left. =A0*/
>> =A0};
>>
>> =A0/* The source language of the translation-unit. =A0*/
>> Index: tree-pass.h
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- tree-pass.h (revision 184971)
>> +++ tree-pass.h (working copy)
>> @@ -455,6 +455,7 @@ extern struct gimple_opt_pass pass_tm_memopt;
>> =A0extern struct gimple_opt_pass pass_tm_edges;
>> =A0extern struct gimple_opt_pass pass_split_functions;
>> =A0extern struct gimple_opt_pass pass_feedback_split_functions;
>> +extern struct gimple_opt_pass pass_dispatch_versions;
>>
>> =A0/* IPA Passes */
>> =A0extern struct simple_ipa_opt_pass pass_ipa_lower_emutls;
>> Index: multiversion.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- multiversion.c =A0 =A0 =A0(revision 0)
>> +++ multiversion.c =A0 =A0 =A0(revision 0)
>> @@ -0,0 +1,798 @@
>> +/* Function Multiversioning.
>> + =A0 Copyright (C) 2012 Free Software Foundation, Inc.
>> + =A0 Contributed by Sriraman Tallam (tmsriram@google.com)
>> +
>> +This file is part of GCC.
>> +
>> +GCC is free software; you can redistribute it and/or modify it under
>> +the terms of the GNU General Public License as published by the Free
>> +Software Foundation; either version 3, or (at your option) any later
>> +version.
>> +
>> +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
>> +WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> +FITNESS FOR A PARTICULAR PURPOSE. =A0See the GNU General Public License
>> +for more details.
>> +
>> +You should have received a copy of the GNU General Public License
>> +along with GCC; see the file COPYING3. =A0If not see
>> +<http://www.gnu.org/licenses/>. */
>> +
>> +/* Holds the state for multi-versioned functions here. The front-end
>> + =A0 updates the state as and when function versions are encountered.
>> + =A0 This is then used to generate the dispatch code. =A0Also, the
>> + =A0 optimization passes to clone hot paths involving versioned functio=
ns
>> + =A0 will be done here.
>> +
>> + =A0 Function versions are created by using the same function signature=
 but
>> + =A0 also tagging attribute "targetv" to specify the platform type for =
which
>> + =A0 the version must be executed. =A0Here is an example:
>> +
>> + =A0 int foo ()
>> + =A0 {
>> + =A0 =A0 printf ("Execute as default");
>> + =A0 =A0 return 0;
>> + =A0 }
>> +
>> + =A0 int =A0__attribute__ ((targetv ("arch=3Dcorei7")))
>> + =A0 foo ()
>> + =A0 {
>> + =A0 =A0 printf ("Execute for corei7");
>> + =A0 =A0 return 0;
>> + =A0 }
>> +
>> + =A0 int main ()
>> + =A0 {
>> + =A0 =A0 return foo ();
>> + =A0 }
>> +
>> + =A0 The call to foo in main is replaced with a call to an IFUNC functi=
on that
>> + =A0 contains the dispatch code to call the correct function version at
>> + =A0 run-time. =A0*/
>> +
>> +
>> +#include "config.h"
>> +#include "system.h"
>> +#include "coretypes.h"
>> +#include "tm.h"
>> +#include "tree.h"
>> +#include "tree-inline.h"
>> +#include "langhooks.h"
>> +#include "flags.h"
>> +#include "cgraph.h"
>> +#include "diagnostic.h"
>> +#include "toplev.h"
>> +#include "timevar.h"
>> +#include "params.h"
>> +#include "fibheap.h"
>> +#include "intl.h"
>> +#include "tree-pass.h"
>> +#include "hashtab.h"
>> +#include "coverage.h"
>> +#include "ggc.h"
>> +#include "tree-flow.h"
>> +#include "rtl.h"
>> +#include "ipa-prop.h"
>> +#include "basic-block.h"
>> +#include "toplev.h"
>> +#include "dbgcnt.h"
>> +#include "tree-dump.h"
>> +#include "output.h"
>> +#include "vecprim.h"
>> +#include "gimple-pretty-print.h"
>> +#include "ipa-inline.h"
>> +#include "target.h"
>> +#include "multiversion.h"
>> +
>> +typedef void * void_p;
>> +
>> +DEF_VEC_P (void_p);
>> +DEF_VEC_ALLOC_P (void_p, heap);
>> +
>> +/* Each function decl that is a function version gets an instance of th=
is
>> + =A0 structure. =A0 Since this is called by the front-end, decl merging=
 can
>> + =A0 happen, where a decl created for a new declaration is merged with
>> + =A0 the old. In this case, the new decl is deleted and the IS_DELETED
>> + =A0 field is set for the struct instance corresponding to the new decl.
>> + =A0 IFUNC_DECL is the decl of the ifunc function for default decls.
>> + =A0 IFUNC_RESOLVER_DECL is the decl of the dispatch function. =A0VERSI=
ONS
>> + =A0 is a vector containing the list of function versions =A0that are
>> + =A0 the candidates for dispatch. =A0*/
>> +
>> +typedef struct version_function_d {
>> + =A0tree decl;
>> + =A0tree ifunc_decl;
>> + =A0tree ifunc_resolver_decl;
>> + =A0VEC (void_p, heap) *versions;
>> + =A0bool is_deleted;
>> +} version_function;
>> +
>> +/* Hashmap has an entry for every function decl that has other function
>> + =A0 versions. =A0For function decls that are the default, it also stor=
es the
>> + =A0 list of all the other function versions. =A0Each entry is a struct=
ure
>> + =A0 of type version_function_d. =A0*/
>> +static htab_t decl_version_htab =3D NULL;
>> +
>> +/* Hashtable helpers for decl_version_htab. */
>> +
>> +static hashval_t
>> +decl_version_htab_hash_descriptor (const void *p)
>> +{
>> + =A0const version_function *t =3D (const version_function *) p;
>> + =A0return htab_hash_pointer (t->decl);
>> +}
>> +
>> +/* Hashtable helper for decl_version_htab. */
>> +
>> +static int
>> +decl_version_htab_eq_descriptor (const void *p1, const void *p2)
>> +{
>> + =A0const version_function *t1 =3D (const version_function *) p1;
>> + =A0return htab_eq_pointer ((const void_p) t1->decl, p2);
>> +}
>> +
>> +/* Create the decl_version_htab. =A0*/
>> +static void
>> +create_decl_version_htab (void)
>> +{
>> + =A0if (decl_version_htab =3D=3D NULL)
>> + =A0 =A0decl_version_htab =3D htab_create (10, decl_version_htab_hash_d=
escriptor,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0decl_version_htab_eq_descriptor, NULL);
>> +}
>> +
>> +/* Creates an instance of version_function for decl DECL. =A0*/
>> +
>> +static version_function*
>> +new_version_function (const tree decl)
>> +{
>> + =A0version_function *v;
>> + =A0v =3D (version_function *)xmalloc(sizeof (version_function));
>> + =A0v->decl =3D decl;
>> + =A0v->ifunc_decl =3D NULL;
>> + =A0v->ifunc_resolver_decl =3D NULL;
>> + =A0v->versions =3D NULL;
>> + =A0v->is_deleted =3D false;
>> + =A0return v;
>> +}
>> +
>> +/* Comparator function to be used in qsort routine to sort attribute
>> + =A0 specification strings to "targetv". =A0*/
>> +
>> +static int
>> +attr_strcmp (const void *v1, const void *v2)
>> +{
>> + =A0const char *c1 =3D *(char *const*)v1;
>> + =A0const char *c2 =3D *(char *const*)v2;
>> + =A0return strcmp (c1, c2);
>> +}
>> +
>> +/* STR is the argument to targetv attribute. =A0This function tokenizes
>> + =A0 the comma separated arguments, sorts them and returns a string whi=
ch
>> + =A0 is a unique identifier for the comma separated arguments. =A0*/
>> +
>> +static char *
>> +sorted_attr_string (const char *str)
>> +{
>> + =A0char **args =3D NULL;
>> + =A0char *attr_str, *ret_str;
>> + =A0char *attr =3D NULL;
>> + =A0unsigned int argnum =3D 1;
>> + =A0unsigned int i;
>> +
>> + =A0for (i =3D 0; i < strlen (str); i++)
>> + =A0 =A0if (str[i] =3D=3D ',')
>> + =A0 =A0 =A0argnum++;
>> +
>> + =A0attr_str =3D (char *)xmalloc (strlen (str) + 1);
>> + =A0strcpy (attr_str, str);
>> +
>> + =A0for (i =3D 0; i < strlen (attr_str); i++)
>> + =A0 =A0if (attr_str[i] =3D=3D '=3D')
>> + =A0 =A0 =A0attr_str[i] =3D '_';
>> +
>> + =A0if (argnum =3D=3D 1)
>> + =A0 =A0return attr_str;
>> +
>> + =A0args =3D (char **)xmalloc (argnum * sizeof (char *));
>> +
>> + =A0i =3D 0;
>> + =A0attr =3D strtok (attr_str, ",");
>> + =A0while (attr !=3D NULL)
>> + =A0 =A0{
>> + =A0 =A0 =A0args[i] =3D attr;
>> + =A0 =A0 =A0i++;
>> + =A0 =A0 =A0attr =3D strtok (NULL, ",");
>> + =A0 =A0}
>> +
>> + =A0qsort (args, argnum, sizeof (char*), attr_strcmp);
>> +
>> + =A0ret_str =3D (char *)xmalloc (strlen (str) + 1);
>> + =A0strcpy (ret_str, args[0]);
>> + =A0for (i =3D 1; i < argnum; i++)
>> + =A0 =A0{
>> + =A0 =A0 =A0strcat (ret_str, "_");
>> + =A0 =A0 =A0strcat (ret_str, args[i]);
>> + =A0 =A0}
>> +
>> + =A0free (args);
>> + =A0free (attr_str);
>> + =A0return ret_str;
>> +}
>> +
>> +/* Returns true when only one of DECL1 and DECL2 is marked with "target=
v"
>> + =A0 or if the "targetv" attribute strings of DECL1 and DECL2 dont matc=
h. =A0*/
>> +
>> +bool
>> +has_different_version_attributes (const tree decl1, const tree decl2)
>> +{
>> + =A0tree attr1, attr2;
>> + =A0char *c1, *c2;
>> + =A0bool ret =3D false;
>> +
>> + =A0if (TREE_CODE (decl1) !=3D FUNCTION_DECL
>> + =A0 =A0 =A0|| TREE_CODE (decl2) !=3D FUNCTION_DECL)
>> + =A0 =A0return false;
>> +
>> + =A0attr1 =3D lookup_attribute ("targetv", DECL_ATTRIBUTES (decl1));
>> + =A0attr2 =3D lookup_attribute ("targetv", DECL_ATTRIBUTES (decl2));
>> +
>> + =A0if (attr1 =3D=3D NULL_TREE && attr2 =3D=3D NULL_TREE)
>> + =A0 =A0return false;
>> +
>> + =A0if ((attr1 =3D=3D NULL_TREE && attr2 !=3D NULL_TREE)
>> + =A0 =A0 =A0|| (attr1 !=3D NULL_TREE && attr2 =3D=3D NULL_TREE))
>> + =A0 =A0return true;
>> +
>> + =A0c1 =3D sorted_attr_string (
>> + =A0 =A0 =A0 TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr1))));
>> + =A0c2 =3D sorted_attr_string (
>> + =A0 =A0 =A0 TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr2))));
>> +
>> + =A0if (strcmp (c1, c2) !=3D 0)
>> + =A0 =A0 ret =3D true;
>> +
>> + =A0free (c1);
>> + =A0free (c2);
>> +
>> + =A0return ret;
>> +}
>> +
>> +/* If this decl corresponds to a function and has "targetv" attribute,
>> + =A0 append the attribute string to its assembler name. =A0*/
>> +
>> +void
>> +version_assembler_name (const tree decl)
>> +{
>> + =A0tree version_attr;
>> + =A0const char *orig_name, *version_string, *attr_str;
>> + =A0char *assembler_name;
>> + =A0tree assembler_name_tree;
>> +
>> + =A0if (TREE_CODE (decl) !=3D FUNCTION_DECL
>> + =A0 =A0 =A0|| DECL_ASSEMBLER_NAME_SET_P (decl)
>> + =A0 =A0 =A0|| !DECL_FUNCTION_VERSIONED (decl))
>> + =A0 =A0return;
>> +
>> + =A0if (DECL_DECLARED_INLINE_P (decl)
>> + =A0 =A0 =A0&&lookup_attribute ("gnu_inline",
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 DECL_ATTRIBUTES (decl)=
))
>> + =A0 =A0error_at (DECL_SOURCE_LOCATION (decl),
>> + =A0 =A0 =A0 =A0 =A0 =A0 "Function versions cannot be marked as gnu_inl=
ine,"
>> + =A0 =A0 =A0 =A0 =A0 =A0 " bodies have to be generated\n");
>> +
>> + =A0if (DECL_VIRTUAL_P (decl)
>> + =A0 =A0 =A0|| DECL_VINDEX (decl))
>> + =A0 =A0error_at (DECL_SOURCE_LOCATION (decl),
>> + =A0 =A0 =A0 =A0 =A0 =A0 "Virtual function versioning not supported\n");
>> +
>> + =A0version_attr =3D lookup_attribute ("targetv", DECL_ATTRIBUTES (decl=
));
>> + =A0/* targetv attribute string is NULL for default functions. =A0*/
>> + =A0if (version_attr =3D=3D NULL_TREE)
>> + =A0 =A0return;
>> +
>> + =A0orig_name =3D IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
>> + =A0version_string
>> + =A0 =A0=3D TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (version_attr))=
);
>> +
>> + =A0attr_str =3D sorted_attr_string (version_string);
>> + =A0assembler_name =3D (char *) xmalloc (strlen (orig_name)
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0+ strlen (attr_str) + 2);
>> +
>> + =A0sprintf (assembler_name, "%s.%s", orig_name, attr_str);
>> + =A0if (dump_file)
>> + =A0 =A0fprintf (dump_file, "Assembler name set to %s for function vers=
ion %s\n",
>> + =A0 =A0 =A0 =A0 =A0 =A0assembler_name, IDENTIFIER_POINTER (DECL_NAME (=
decl)));
>> + =A0assembler_name_tree =3D get_identifier (assembler_name);
>> + =A0SET_DECL_ASSEMBLER_NAME (decl, assembler_name_tree);
>> +}
>> +
>> +/* Returns true if decl is multi-versioned and DECL is the default func=
tion,
>> + =A0 that is it is not tagged with "targetv" attribute. =A0*/
>> +
>> +bool
>> +is_default_function (const tree decl)
>> +{
>> + =A0return (TREE_CODE (decl) =3D=3D FUNCTION_DECL
>> + =A0 =A0 =A0 =A0 && DECL_FUNCTION_VERSIONED (decl)
>> + =A0 =A0 =A0 =A0 && (lookup_attribute ("targetv", DECL_ATTRIBUTES (decl=
))
>> + =A0 =A0 =A0 =A0 =A0 =A0 =3D=3D NULL_TREE));
>> +}
>> +
>> +/* For function decl DECL, find the version_function struct in the
>> + =A0 decl_version_htab. =A0*/
>> +
>> +static version_function *
>> +find_function_version (const tree decl)
>> +{
>> + =A0void *slot;
>> +
>> + =A0if (!DECL_FUNCTION_VERSIONED (decl))
>> + =A0 =A0return NULL;
>> +
>> + =A0if (!decl_version_htab)
>> + =A0 =A0return NULL;
>> +
>> + =A0slot =3D htab_find_with_hash (decl_version_htab, decl,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0htab_hash_p=
ointer (decl));
>> +
>> + =A0if (slot !=3D NULL)
>> + =A0 =A0return (version_function *)slot;
>> +
>> + =A0return NULL;
>> +}
>> +
>> +/* Record DECL as a function version by creating a version_function str=
uct
>> + =A0 for it and storing it in the hashtable. =A0*/
>> +
>> +static version_function *
>> +add_function_version (const tree decl)
>> +{
>> + =A0void **slot;
>> + =A0version_function *v;
>> +
>> + =A0if (!DECL_FUNCTION_VERSIONED (decl))
>> + =A0 =A0return NULL;
>> +
>> + =A0create_decl_version_htab ();
>> +
>> + =A0slot =3D htab_find_slot_with_hash (decl_version_htab, (const void_p=
)decl,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ht=
ab_hash_pointer ((const void_p)decl),
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0INS=
ERT);
>> +
>> + =A0if (*slot !=3D NULL)
>> + =A0 =A0return (version_function *)*slot;
>> +
>> + =A0v =3D new_version_function (decl);
>> + =A0*slot =3D v;
>> +
>> + =A0return v;
>> +}
>> +
>> +/* Push V into VEC only if it is not already present. =A0*/
>> +
>> +static void
>> +push_function_version (version_function *v, VEC (void_p, heap) *vec)
>> +{
>> + =A0int ix;
>> + =A0void_p ele;
>> + =A0for (ix =3D 0; VEC_iterate (void_p, vec, ix, ele); ++ix)
>> + =A0 =A0{
>> + =A0 =A0 =A0if (ele =3D=3D (void_p)v)
>> + =A0 =A0 =A0 =A0return;
>> + =A0 =A0}
>> +
>> + =A0VEC_safe_push (void_p, heap, vec, (void*)v);
>> +}
>> +
>> +/* Mark DECL as deleted. =A0This is called by the front-end when a dupl=
icate
>> + =A0 decl is merged with the original decl and the duplicate decl is de=
leted.
>> + =A0 This function marks the duplicate_decl as invalid. =A0Called by
>> + =A0 duplicate_decls in cp/decl.c. =A0*/
>> +
>> +void
>> +mark_delete_decl_version (const tree decl)
>> +{
>> + =A0version_function *decl_v;
>> +
>> + =A0decl_v =3D find_function_version (decl);
>> +
>> + =A0if (decl_v =3D=3D NULL)
>> + =A0 =A0return;
>> +
>> + =A0decl_v->is_deleted =3D true;
>> +
>> + =A0if (is_default_function (decl)
>> + =A0 =A0 =A0&& decl_v->versions !=3D NULL)
>> + =A0 =A0{
>> + =A0 =A0 =A0VEC_truncate (void_p, decl_v->versions, 0);
>> + =A0 =A0 =A0VEC_free (void_p, heap, decl_v->versions);
>> + =A0 =A0}
>> +}
>> +
>> +/* Mark DECL1 and DECL2 to be function versions in the same group. =A0O=
ne
>> + =A0 of DECL1 and DECL2 must be the default, otherwise this function do=
es
>> + =A0 nothing. =A0This function aggregates the versions. =A0*/
>> +
>> +int
>> +group_function_versions (const tree decl1, const tree decl2)
>> +{
>> + =A0tree default_decl, version_decl;
>> + =A0version_function *default_v, *version_v;
>> +
>> + =A0gcc_assert (DECL_FUNCTION_VERSIONED (decl1)
>> + =A0 =A0 =A0 =A0 =A0 =A0 && DECL_FUNCTION_VERSIONED (decl2));
>> +
>> + =A0/* The version decls are added only to the default decl. =A0*/
>> + =A0if (!is_default_function (decl1)
>> + =A0 =A0 =A0&& !is_default_function (decl2))
>> + =A0 =A0return 0;
>> +
>> + =A0/* This can happen with duplicate declarations. =A0Just ignore. =A0=
*/
>> + =A0if (is_default_function (decl1)
>> + =A0 =A0 =A0&& is_default_function (decl2))
>> + =A0 =A0return 0;
>> +
>> + =A0default_decl =3D (is_default_function (decl1)) ? decl1 : decl2;
>> + =A0version_decl =3D (default_decl =3D=3D decl1) ? decl2 : decl1;
>> +
>> + =A0gcc_assert (default_decl !=3D version_decl);
>> + =A0create_decl_version_htab ();
>> +
>> + =A0/* If the version function is found, it has been added. =A0*/
>> + =A0if (find_function_version (version_decl))
>> + =A0 =A0return 0;
>> +
>> + =A0default_v =3D add_function_version (default_decl);
>> + =A0version_v =3D add_function_version (version_decl);
>> +
>> + =A0if (default_v->versions =3D=3D NULL)
>> + =A0 =A0default_v->versions =3D VEC_alloc (void_p, heap, 1);
>> +
>> + =A0push_function_version (version_v, default_v->versions);
>> + =A0return 0;
>> +}
>> +
>> +/* Makes a function attribute of the form NAME(ARG_NAME) and chains
>> + =A0 it to CHAIN. =A0*/
>> +
>> +static tree
>> +make_attribute (const char *name, const char *arg_name, tree chain)
>> +{
>> + =A0tree attr_name;
>> + =A0tree attr_arg_name;
>> + =A0tree attr_args;
>> + =A0tree attr;
>> +
>> + =A0attr_name =3D get_identifier (name);
>> + =A0attr_arg_name =3D build_string (strlen (arg_name), arg_name);
>> + =A0attr_args =3D tree_cons (NULL_TREE, attr_arg_name, NULL_TREE);
>> + =A0attr =3D tree_cons (attr_name, attr_args, chain);
>> + =A0return attr;
>> +}
>> +
>> +/* Return a new name by appending SUFFIX to the DECL name. =A0If
>> + =A0 make_unique is true, append the full path name. =A0*/
>> +
>> +static char *
>> +make_name (tree decl, const char *suffix, bool make_unique)
>> +{
>> + =A0char *global_var_name;
>> + =A0int name_len;
>> + =A0const char *name;
>> + =A0const char *unique_name =3D NULL;
>> +
>> + =A0name =3D IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
>> +
>> + =A0/* Get a unique name that can be used globally without any chances
>> + =A0 =A0 of collision at link time. =A0*/
>> + =A0if (make_unique)
>> + =A0 =A0unique_name =3D IDENTIFIER_POINTER (get_file_function_name ("\0=
"));
>> +
>> + =A0name_len =3D strlen (name) + strlen (suffix) + 2;
>> +
>> + =A0if (make_unique)
>> + =A0 =A0name_len +=3D strlen (unique_name) + 1;
>> + =A0global_var_name =3D (char *) xmalloc (name_len);
>> +
>> + =A0/* Use '.' to concatenate names as it is demangler friendly. =A0*/
>> + =A0if (make_unique)
>> + =A0 =A0 =A0snprintf (global_var_name, name_len, "%s.%s.%s", name,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 unique_name, suffix);
>> + =A0else
>> + =A0 =A0 =A0snprintf (global_var_name, name_len, "%s.%s", name, suffix);
>> +
>> + =A0return global_var_name;
>> +}
>> +
>> +/* Make the resolver function decl for ifunc (IFUNC_DECL) to dispatch
>> + =A0 the versions of multi-versioned function DEFAULT_DECL. =A0Create a=
nd
>> + =A0 empty basic block in the resolver and store the pointer in
>> + =A0 EMPTY_BB. =A0Return the decl of the resolver function. =A0*/
>> +
>> +static tree
>> +make_ifunc_resolver_func (const tree default_decl,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 const tree ifunc_decl,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 basic_block *empty_bb)
>> +{
>> + =A0char *resolver_name;
>> + =A0tree decl, type, decl_name, t;
>> + =A0basic_block new_bb;
>> + =A0tree old_current_function_decl;
>> + =A0bool make_unique =3D false;
>> +
>> + =A0/* IFUNC's have to be globally visible. =A0So, if the default_decl =
is
>> + =A0 =A0 not, then the name of the IFUNC should be made unique. =A0*/
>> + =A0if (TREE_PUBLIC (default_decl) =3D=3D 0)
>> + =A0 =A0make_unique =3D true;
>> +
>> + =A0/* Append the filename to the resolver function if the versions are
>> + =A0 =A0 not externally visible. =A0This is because the resolver functi=
on has
>> + =A0 =A0 to be externally visible for the loader to find it. =A0So, app=
ending
>> + =A0 =A0 the filename will prevent conflicts with a resolver function f=
rom
>> + =A0 =A0 another module which is based on the same version name. =A0*/
>> + =A0resolver_name =3D make_name (default_decl, "resolver", make_unique);
>> +
>> + =A0/* The resolver function should return a (void *). */
>> + =A0type =3D build_function_type_list (ptr_type_node, NULL_TREE);
>> +
>> + =A0decl =3D build_fn_decl (resolver_name, type);
>> + =A0decl_name =3D get_identifier (resolver_name);
>> + =A0SET_DECL_ASSEMBLER_NAME (decl, decl_name);
>> +
>> + =A0DECL_NAME (decl) =3D decl_name;
>> + =A0TREE_USED (decl) =3D TREE_USED (default_decl);
>> + =A0DECL_ARTIFICIAL (decl) =3D 1;
>> + =A0DECL_IGNORED_P (decl) =3D 0;
>> + =A0/* IFUNC resolvers have to be externally visible. =A0*/
>> + =A0TREE_PUBLIC (decl) =3D 1;
>> + =A0DECL_UNINLINABLE (decl) =3D 1;
>> +
>> + =A0DECL_EXTERNAL (decl) =3D DECL_EXTERNAL (default_decl);
>> + =A0DECL_EXTERNAL (ifunc_decl) =3D 0;
>> +
>> + =A0DECL_CONTEXT (decl) =3D NULL_TREE;
>> + =A0DECL_INITIAL (decl) =3D make_node (BLOCK);
>> + =A0DECL_STATIC_CONSTRUCTOR (decl) =3D 0;
>> + =A0TREE_READONLY (decl) =3D 0;
>> + =A0DECL_PURE_P (decl) =3D 0;
>> + =A0DECL_COMDAT (decl) =3D DECL_COMDAT (default_decl);
>> + =A0if (DECL_COMDAT_GROUP (default_decl))
>> + =A0 =A0{
>> + =A0 =A0 =A0make_decl_one_only (decl, DECL_COMDAT_GROUP (default_decl));
>> + =A0 =A0}
>> + =A0/* Build result decl and add to function_decl. */
>> + =A0t =3D build_decl (UNKNOWN_LOCATION, RESULT_DECL, NULL_TREE, ptr_typ=
e_node);
>> + =A0DECL_ARTIFICIAL (t) =3D 1;
>> + =A0DECL_IGNORED_P (t) =3D 1;
>> + =A0DECL_RESULT (decl) =3D t;
>> +
>> + =A0gimplify_function_tree (decl);
>> + =A0old_current_function_decl =3D current_function_decl;
>> + =A0push_cfun (DECL_STRUCT_FUNCTION (decl));
>> + =A0current_function_decl =3D decl;
>> + =A0init_empty_tree_cfg_for_function (DECL_STRUCT_FUNCTION (decl));
>> + =A0cfun->curr_properties |=3D
>> + =A0 =A0(PROP_gimple_lcf | PROP_gimple_leh | PROP_cfg | PROP_referenced=
_vars |
>> + =A0 =A0 PROP_ssa);
>> + =A0new_bb =3D create_empty_bb (ENTRY_BLOCK_PTR);
>> + =A0make_edge (ENTRY_BLOCK_PTR, new_bb, EDGE_FALLTHRU);
>> + =A0make_edge (new_bb, EXIT_BLOCK_PTR, 0);
>> + =A0*empty_bb =3D new_bb;
>> +
>> + =A0cgraph_add_new_function (decl, true);
>> + =A0cgraph_call_function_insertion_hooks (cgraph_get_create_node (decl)=
);
>> + =A0cgraph_analyze_function (cgraph_get_create_node (decl));
>> + =A0cgraph_mark_needed_node (cgraph_get_create_node (decl));
>> +
>> + =A0if (DECL_COMDAT_GROUP (default_decl))
>> + =A0 =A0{
>> + =A0 =A0 =A0gcc_assert (cgraph_get_node (default_decl));
>> + =A0 =A0 =A0cgraph_add_to_same_comdat_group (cgraph_get_node (decl),
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0cgraph_get_node (default_decl));
>> + =A0 =A0}
>> +
>> + =A0pop_cfun ();
>> + =A0current_function_decl =3D old_current_function_decl;
>> +
>> + =A0gcc_assert (ifunc_decl !=3D NULL);
>> + =A0DECL_ATTRIBUTES (ifunc_decl)
>> + =A0 =A0=3D make_attribute ("ifunc", resolver_name, DECL_ATTRIBUTES (if=
unc_decl));
>> + =A0assemble_alias (ifunc_decl, get_identifier (resolver_name));
>> + =A0return decl;
>> +}
>> +
>> +/* Make and ifunc declaration for the multi-versioned function DECL. =
=A0Calls to
>> + =A0 DECL function will be replaced with calls to the ifunc. =A0 Return=
 the decl
>> + =A0 of the ifunc created. =A0*/
>> +
>> +static tree
>> +make_ifunc_func (const tree decl)
>> +{
>> + =A0tree ifunc_decl;
>> + =A0char *ifunc_name, *resolver_name;
>> + =A0tree fn_type, ifunc_type;
>> + =A0bool make_unique =3D false;
>> +
>> + =A0if (TREE_PUBLIC (decl) =3D=3D 0)
>> + =A0 =A0make_unique =3D true;
>> +
>> + =A0ifunc_name =3D make_name (decl, "ifunc", make_unique);
>> + =A0resolver_name =3D make_name (decl, "resolver", make_unique);
>> + =A0gcc_assert (resolver_name);
>> +
>> + =A0fn_type =3D TREE_TYPE (decl);
>> + =A0ifunc_type =3D build_function_type (TREE_TYPE (fn_type),
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 TY=
PE_ARG_TYPES (fn_type));
>> +
>> + =A0ifunc_decl =3D build_fn_decl (ifunc_name, ifunc_type);
>> + =A0TREE_USED (ifunc_decl) =3D 1;
>> + =A0DECL_CONTEXT (ifunc_decl) =3D NULL_TREE;
>> + =A0DECL_INITIAL (ifunc_decl) =3D error_mark_node;
>> + =A0DECL_ARTIFICIAL (ifunc_decl) =3D 1;
>> + =A0/* Mark this ifunc as external, the resolver will flip it again if
>> + =A0 =A0 it gets generated. =A0*/
>> + =A0DECL_EXTERNAL (ifunc_decl) =3D 1;
>> + =A0/* IFUNCs have to be externally visible. =A0*/
>> + =A0TREE_PUBLIC (ifunc_decl) =3D 1;
>> +
>> + =A0return ifunc_decl;
>> +}
>> +
>> +/* For multi-versioned function decl, which should also be the default,
>> + =A0 return the decl of the ifunc resolver, create it if it does not
>> + =A0 exist. =A0*/
>> +
>> +tree
>> +get_ifunc_for_version (const tree decl)
>> +{
>> + =A0version_function *decl_v;
>> + =A0int ix;
>> + =A0void_p ele;
>> +
>> + =A0/* DECL has to be the default version, otherwise it is missing and
>> + =A0 =A0 that is not allowed. =A0*/
>> + =A0if (!is_default_function (decl))
>> + =A0 =A0{
>> + =A0 =A0 =A0error_at (DECL_SOURCE_LOCATION (decl), "Default version not=
 found");
>> + =A0 =A0 =A0return decl;
>> + =A0 =A0}
>> +
>> + =A0decl_v =3D find_function_version (decl);
>> + =A0gcc_assert (decl_v !=3D NULL);
>> + =A0if (decl_v->ifunc_decl =3D=3D NULL)
>> + =A0 =A0{
>> + =A0 =A0 =A0tree ifunc_decl;
>> + =A0 =A0 =A0ifunc_decl =3D make_ifunc_func (decl);
>> + =A0 =A0 =A0decl_v->ifunc_decl =3D ifunc_decl;
>> + =A0 =A0}
>> +
>> + =A0if (cgraph_get_node (decl))
>> + =A0 =A0cgraph_mark_needed_node (cgraph_get_node (decl));
>> +
>> + =A0for (ix =3D 0; VEC_iterate (void_p, decl_v->versions, ix, ele); ++i=
x)
>> + =A0 =A0{
>> + =A0 =A0 =A0version_function *v =3D (version_function *) ele;
>> + =A0 =A0 =A0gcc_assert (v->decl !=3D NULL);
>> + =A0 =A0 =A0if (cgraph_get_node (v->decl))
>> + =A0 =A0 =A0 cgraph_mark_needed_node (cgraph_get_node (v->decl));
>> + =A0 =A0}
>> +
>> + =A0return decl_v->ifunc_decl;
>> +}
>> +
>> +/* Generate the dispatching code to dispatch multi-versioned function
>> + =A0 DECL. =A0Make a new function decl for dispatching and call the tar=
get
>> + =A0 hook to process the "targetv" attributes and provide the code to
>> + =A0 dispatch the right function at run-time. =A0*/
>> +
>> +static tree
>> +make_ifunc_resolver_for_version (const tree decl)
>> +{
>> + =A0version_function *decl_v;
>> + =A0tree ifunc_resolver_decl, ifunc_decl;
>> + =A0basic_block empty_bb;
>> + =A0int ix;
>> + =A0void_p ele;
>> + =A0VEC (tree, heap) *fn_ver_vec =3D NULL;
>> +
>> + =A0gcc_assert (is_default_function (decl));
>> +
>> + =A0decl_v =3D find_function_version (decl);
>> + =A0gcc_assert (decl_v !=3D NULL);
>> +
>> + =A0if (decl_v->ifunc_resolver_decl !=3D NULL)
>> + =A0 =A0return decl_v->ifunc_resolver_decl;
>> +
>> + =A0ifunc_decl =3D decl_v->ifunc_decl;
>> +
>> + =A0if (ifunc_decl =3D=3D NULL)
>> + =A0 =A0ifunc_decl =3D decl_v->ifunc_decl =3D make_ifunc_func (decl);
>> +
>> + =A0ifunc_resolver_decl =3D make_ifunc_resolver_func (decl, ifunc_decl,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 &empty_bb);
>> +
>> + =A0fn_ver_vec =3D VEC_alloc (tree, heap, 2);
>> + =A0VEC_safe_push (tree, heap, fn_ver_vec, decl);
>> +
>> + =A0for (ix =3D 0; VEC_iterate (void_p, decl_v->versions, ix, ele); ++i=
x)
>> + =A0 =A0{
>> + =A0 =A0 =A0version_function *v =3D (version_function *) ele;
>> + =A0 =A0 =A0gcc_assert (v->decl !=3D NULL);
>> + =A0 =A0 =A0/* Check for virtual functions here again, as by this time =
it should
>> + =A0 =A0 =A0 =A0have been determined if this function needs a vtable in=
dex or
>> + =A0 =A0 =A0 =A0not. =A0This happens for methods in derived classes tha=
t override
>> + =A0 =A0 =A0 =A0virtual methods in base classes but are not explicitly =
marked as
>> + =A0 =A0 =A0 =A0virtual. =A0*/
>> + =A0 =A0 =A0if (DECL_VINDEX (v->decl))
>> + =A0 =A0 =A0 =A0error_at (DECL_SOURCE_LOCATION (v->decl),
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 "Virtual function versioning not suppo=
rted\n");
>> + =A0 =A0 =A0if (!v->is_deleted)
>> + =A0 =A0 =A0 VEC_safe_push (tree, heap, fn_ver_vec, v->decl);
>> + =A0 =A0}
>> +
>> + =A0gcc_assert (targetm.dispatch_version);
>> + =A0targetm.dispatch_version (ifunc_resolver_decl, fn_ver_vec, &empty_b=
b);
>> + =A0decl_v->ifunc_resolver_decl =3D ifunc_resolver_decl;
>> +
>> + =A0return ifunc_resolver_decl;
>> +}
>> +
>> +/* Main entry point to pass_dispatch_versions. For multi-versioned func=
tions,
>> + =A0 generate the dispatching code. =A0*/
>> +
>> +static unsigned int
>> +do_dispatch_versions (void)
>> +{
>> + =A0/* A new pass for generating dispatch code for multi-versioned func=
tions.
>> + =A0 =A0 Other forms of dispatch can be added when ifunc support is not=
 available
>> + =A0 =A0 like just calling the function directly after checking for tar=
get type.
>> + =A0 =A0 Currently, dispatching is done through IFUNC. =A0This pass wil=
l become
>> + =A0 =A0 more meaningful when other dispatch mechanisms are added. =A0*/
>> +
>> + =A0/* Cloning a function to produce more versions will happen here whe=
n the
>> + =A0 =A0 user requests that via the targetv attribute. For example,
>> + =A0 =A0 int foo () __attribute__ ((targetv(("arch=3Dcore2"), ("arch=3D=
corei7"))));
>> + =A0 =A0 means that the user wants the same body of foo to be versioned=
 for core2
>> + =A0 =A0 and corei7. =A0In that case, this function will be cloned duri=
ng this
>> + =A0 =A0 pass. =A0*/
>> +
>> + =A0if (DECL_FUNCTION_VERSIONED (current_function_decl)
>> + =A0 =A0 =A0&& is_default_function (current_function_decl))
>> + =A0 =A0{
>> + =A0 =A0 =A0tree decl =3D make_ifunc_resolver_for_version (current_func=
tion_decl);
>> + =A0 =A0 =A0if (dump_file && decl)
>> + =A0 =A0 =A0 dump_function_to_file (decl, dump_file, TDF_BLOCKS);
>> + =A0 =A0}
>> + =A0return 0;
>> +}
>> +
>> +static =A0bool
>> +gate_dispatch_versions (void)
>> +{
>> + =A0return true;
>> +}
>> +
>> +/* A pass to generate the dispatch code to execute the appropriate vers=
ion
>> + =A0 of a multi-versioned function at run-time. =A0*/
>> +
>> +struct gimple_opt_pass pass_dispatch_versions =3D
>> +{
>> + {
>> + =A0GIMPLE_PASS,
>> + =A0"dispatch_multiversion_functions", =A0 =A0/* name */
>> + =A0gate_dispatch_versions, =A0 =A0 =A0 =A0 =A0 =A0 =A0/* gate */
>> + =A0do_dispatch_versions, =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0/* execute */
>> + =A0NULL, =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0/* sub */
>> + =A0NULL, =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0/* next */
>> + =A00, =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 /* static_pass_number */
>> + =A0TV_MULTIVERSION_DISPATCH, =A0 =A0 =A0 =A0 =A0 =A0/* tv_id */
>> + =A0PROP_cfg, =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0/*=
 properties_required */
>> + =A0PROP_cfg, =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0/*=
 properties_provided */
>> + =A00, =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 /* properties_destroyed */
>> + =A00, =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 /* todo_flags_start */
>> + =A0TODO_dump_func | =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 /* todo_fl=
ags_finish */
>> + =A0TODO_cleanup_cfg | TODO_dump_cgraph
>> + }
>> +};
>> Index: cgraphunit.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- cgraphunit.c =A0 =A0 =A0 =A0(revision 184971)
>> +++ cgraphunit.c =A0 =A0 =A0 =A0(working copy)
>> @@ -141,6 +141,7 @@ along with GCC; see the file COPYING3. =A0If not see
>> =A0#include "ipa-inline.h"
>> =A0#include "ipa-utils.h"
>> =A0#include "lto-streamer.h"
>> +#include "multiversion.h"
>>
>> =A0static void cgraph_expand_all_functions (void);
>> =A0static void cgraph_mark_functions_to_output (void);
>> @@ -343,6 +344,13 @@ cgraph_finalize_function (tree decl, bool nested)
>> =A0 =A0 =A0 node->local.redefined_extern_inline =3D true;
>> =A0 =A0 }
>>
>> + =A0/* If this is a function version and not the default, change the
>> + =A0 =A0 assembler name of this function. =A0The DECL names of function
>> + =A0 =A0 versions are the same, only the assembler names are made uniqu=
e.
>> + =A0 =A0 The assembler name is changed by appending the string from
>> + =A0 =A0 the "targetv" attribute. =A0*/
>> + =A0version_assembler_name (decl);
>> +
>> =A0 notice_global_symbol (decl);
>> =A0 node->local.finalized =3D true;
>> =A0 node->lowered =3D DECL_STRUCT_FUNCTION (decl)->cfg !=3D NULL;
>> Index: multiversion.h
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- multiversion.h =A0 =A0 =A0(revision 0)
>> +++ multiversion.h =A0 =A0 =A0(revision 0)
>> @@ -0,0 +1,52 @@
>> +/* Function Multiversioning.
>> + =A0 Copyright (C) 2012 Free Software Foundation, Inc.
>> + =A0 Contributed by Sriraman Tallam (tmsriram@google.com)
>> +
>> +This file is part of GCC.
>> +
>> +GCC is free software; you can redistribute it and/or modify it under
>> +the terms of the GNU General Public License as published by the Free
>> +Software Foundation; either version 3, or (at your option) any later
>> +version.
>> +
>> +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
>> +WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> +FITNESS FOR A PARTICULAR PURPOSE. =A0See the GNU General Public License
>> +for more details.
>> +
>> +You should have received a copy of the GNU General Public License
>> +along with GCC; see the file COPYING3. =A0If not see
>> +<http://www.gnu.org/licenses/>. */
>> +
>> +/* This is the header file which provides the functions to keep track
>> + =A0 of functions that are multi-versioned and to generate the dispatch
>> + =A0 code to call the right version at run-time. =A0*/
>> +
>> +#ifndef GCC_MULTIVERSION_H
>> +#define GCC_MULTIVERION_H
>> +
>> +#include "tree.h"
>> +
>> +/* Mark DECL1 and DECL2 as function versions. =A0*/
>> +int group_function_versions (const tree decl1, const tree decl2);
>> +
>> +/* Mark DECL as deleted and no longer a version. =A0*/
>> +void mark_delete_decl_version (const tree decl);
>> +
>> +/* Returns true if DECL is the default version to be executed if all
>> + =A0 other versions are inappropriate at run-time. =A0*/
>> +bool is_default_function (const tree decl);
>> +
>> +/* Gets the IFUNC dispatcher for this multi-versioned function DECL. DE=
CL
>> + =A0 must be the default function in the multi-versioned group. =A0*/
>> +tree get_ifunc_for_version (const tree decl);
>> +
>> +/* Returns true when only one of DECL1 and DECL2 is marked with "target=
v"
>> + =A0 or if the "targetv" attribute strings of =A0DECL1 and DECL2 dont m=
atch. =A0*/
>> +bool has_different_version_attributes (const tree decl1, const tree dec=
l2);
>> +
>> +/* If DECL is a function version and not the default version, the assem=
bler
>> + =A0 name of DECL is changed to include the attribute string to keep the
>> + =A0 name unambiguous. =A0*/
>> +void version_assembler_name (const tree decl);
>> +#endif
>> Index: cp/class.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- cp/class.c =A0(revision 184971)
>> +++ cp/class.c =A0(working copy)
>> @@ -38,6 +38,7 @@ along with GCC; see the file COPYING3. =A0If not see
>> =A0#include "tree-dump.h"
>> =A0#include "splay-tree.h"
>> =A0#include "pointer-set.h"
>> +#include "multiversion.h"
>>
>> =A0/* The number of nested classes being processed. =A0If we are not in =
the
>> =A0 =A0scope of any class, this is zero. =A0*/
>> @@ -1092,7 +1093,20 @@ add_method (tree type, tree method, tree using_dec
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0|| same_type_p (TREE_TYPE (fn_type),
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0TREE_TYPE (me=
thod_type))))
>> =A0 =A0 =A0 =A0{
>> - =A0 =A0 =A0 =A0 if (using_decl)
>> + =A0 =A0 =A0 =A0 /* For function versions, their parms and types match
>> + =A0 =A0 =A0 =A0 =A0 =A0but they are not duplicates. =A0Record function=
 versions
>> + =A0 =A0 =A0 =A0 =A0 =A0as and when they are found. =A0*/
>> + =A0 =A0 =A0 =A0 if (TREE_CODE (fn) =3D=3D FUNCTION_DECL
>> + =A0 =A0 =A0 =A0 =A0 =A0 && TREE_CODE (method) =3D=3D FUNCTION_DECL
>> + =A0 =A0 =A0 =A0 =A0 =A0 && (DECL_FUNCTION_VERSIONED (fn)
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 || DECL_FUNCTION_VERSIONED (method)))
>> + =A0 =A0 =A0 =A0 =A0 {
>> + =A0 =A0 =A0 =A0 =A0 =A0 DECL_FUNCTION_VERSIONED (fn) =3D 1;
>> + =A0 =A0 =A0 =A0 =A0 =A0 DECL_FUNCTION_VERSIONED (method) =3D 1;
>> + =A0 =A0 =A0 =A0 =A0 =A0 group_function_versions (fn, method);
>> + =A0 =A0 =A0 =A0 =A0 =A0 continue;
>> + =A0 =A0 =A0 =A0 =A0 }
>> + =A0 =A0 =A0 =A0 else if (using_decl)
>> =A0 =A0 =A0 =A0 =A0 =A0{
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0if (DECL_CONTEXT (fn) =3D=3D type)
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0/* Defer to the local function. =A0*/
>> @@ -1150,6 +1164,13 @@ add_method (tree type, tree method, tree using_dec
>> =A0 else
>> =A0 =A0 /* Replace the current slot. =A0*/
>> =A0 =A0 VEC_replace (tree, method_vec, slot, overload);
>> +
>> + =A0/* Change the assembler name of method here if it has "targetv"
>> + =A0 =A0 attributes. =A0Since all versions have the same mangled name,
>> + =A0 =A0 their assembler name is changed by appending the string from
>> + =A0 =A0 the "targetv" attribute. */
>> + =A0version_assembler_name (method);
>> +
>> =A0 return true;
>> =A0}
>>
>> @@ -6890,8 +6911,11 @@ resolve_address_of_overloaded_function (tree targe
>> =A0 =A0 =A0 =A0 =A0if (DECL_ANTICIPATED (fn))
>> =A0 =A0 =A0 =A0 =A0 =A0continue;
>>
>> - =A0 =A0 =A0 =A0 /* See if there's a match. =A0*/
>> - =A0 =A0 =A0 =A0 if (same_type_p (target_fn_type, static_fn_type (fn)))
>> + =A0 =A0 =A0 =A0 /* See if there's a match. =A0 For functions that are =
multi-versioned
>> + =A0 =A0 =A0 =A0 =A0 =A0match it to the default function. =A0*/
>> + =A0 =A0 =A0 =A0 if (same_type_p (target_fn_type, static_fn_type (fn))
>> + =A0 =A0 =A0 =A0 =A0 =A0 && (!DECL_FUNCTION_VERSIONED (fn)
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 || is_default_function (fn)))
>> =A0 =A0 =A0 =A0 =A0 =A0matches =3D tree_cons (fn, NULL_TREE, matches);
>> =A0 =A0 =A0 =A0}
>> =A0 =A0 }
>> @@ -7053,6 +7077,21 @@ resolve_address_of_overloaded_function (tree targe
>> =A0 =A0 =A0 perform_or_defer_access_check (access_path, fn, fn);
>> =A0 =A0 }
>>
>> + =A0/* If a pointer to a function that is multi-versioned is requested,=
 the
>> + =A0 =A0 pointer to the dispatcher function is returned instead. =A0Thi=
s works
>> + =A0 =A0 well because indirectly calling the function will dispatch the=
 right
>> + =A0 =A0 function version at run-time. Also, the function address is ke=
pt
>> + =A0 =A0 unique. =A0*/
>> + =A0if (DECL_FUNCTION_VERSIONED (fn)
>> + =A0 =A0 =A0&& is_default_function (fn))
>> + =A0 =A0{
>> + =A0 =A0 =A0tree ifunc_decl;
>> + =A0 =A0 =A0ifunc_decl =3D get_ifunc_for_version (fn);
>> + =A0 =A0 =A0gcc_assert (ifunc_decl !=3D NULL);
>> + =A0 =A0 =A0mark_used (fn);
>> + =A0 =A0 =A0return build_fold_addr_expr (ifunc_decl);
>> + =A0 =A0}
>> +
>> =A0 if (TYPE_PTRFN_P (target_type) || TYPE_PTRMEMFUNC_P (target_type))
>> =A0 =A0 return cp_build_addr_expr (fn, flags);
>> =A0 else
>> Index: cp/decl.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- cp/decl.c =A0 (revision 184971)
>> +++ cp/decl.c =A0 (working copy)
>> @@ -54,6 +54,7 @@ along with GCC; see the file COPYING3. =A0If not see
>> =A0#include "pointer-set.h"
>> =A0#include "splay-tree.h"
>> =A0#include "plugin.h"
>> +#include "multiversion.h"
>>
>> =A0/* Possible cases of bad specifiers type used by bad_specifiers. */
>> =A0enum bad_spec_place {
>> @@ -972,6 +973,23 @@ decls_match (tree newdecl, tree olddecl)
>> =A0 =A0 =A0 if (t1 !=3D t2)
>> =A0 =A0 =A0 =A0return 0;
>>
>> + =A0 =A0 =A0/* The decls dont match if they correspond to two different=
 versions
>> + =A0 =A0 =A0 =A0of the same function. =A0*/
>> + =A0 =A0 =A0if (compparms (p1, p2)
>> + =A0 =A0 =A0 =A0 && same_type_p (TREE_TYPE (f1), TREE_TYPE (f2))
>> + =A0 =A0 =A0 =A0 && (DECL_FUNCTION_VERSIONED (newdecl)
>> + =A0 =A0 =A0 =A0 =A0 =A0 || DECL_FUNCTION_VERSIONED (olddecl))
>> + =A0 =A0 =A0 =A0 && has_different_version_attributes (newdecl, olddecl))
>> + =A0 =A0 =A0 {
>> + =A0 =A0 =A0 =A0 /* One of the decls could be the default without the "=
targetv"
>> + =A0 =A0 =A0 =A0 =A0 =A0attribute. Set it to be a versioned function he=
re. =A0*/
>> + =A0 =A0 =A0 =A0 DECL_FUNCTION_VERSIONED (newdecl) =3D 1;
>> + =A0 =A0 =A0 =A0 DECL_FUNCTION_VERSIONED (olddecl) =3D 1;
>> + =A0 =A0 =A0 =A0 /* Accumulate all the versions of a function. =A0*/
>> + =A0 =A0 =A0 =A0 group_function_versions (olddecl, newdecl);
>> + =A0 =A0 =A0 =A0 return 0;
>> + =A0 =A0 =A0 }
>> +
>> =A0 =A0 =A0 if (CP_DECL_CONTEXT (newdecl) !=3D CP_DECL_CONTEXT (olddecl)
>> =A0 =A0 =A0 =A0 =A0&& ! (DECL_EXTERN_C_P (newdecl)
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0&& DECL_EXTERN_C_P (olddecl)))
>> @@ -1482,7 +1500,11 @@ duplicate_decls (tree newdecl, tree olddecl, bool
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0error ("previous declaration %q+#D here", old=
decl);
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0return NULL_TREE;
>> =A0 =A0 =A0 =A0 =A0 =A0}
>> - =A0 =A0 =A0 =A0 else if (compparms (TYPE_ARG_TYPES (TREE_TYPE (newdecl=
)),
>> + =A0 =A0 =A0 =A0 /* For function versions, params and types match, but =
they
>> + =A0 =A0 =A0 =A0 =A0 =A0are not ambiguous. =A0*/
>> + =A0 =A0 =A0 =A0 else if ((!DECL_FUNCTION_VERSIONED (newdecl)
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 && !DECL_FUNCTION_VERSIONED (oldde=
cl))
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0&& compparms (TYPE_ARG_TYPES (TREE_=
TYPE (newdecl)),
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0TYPE_ARG_TYPE=
S (TREE_TYPE (olddecl))))
>> =A0 =A0 =A0 =A0 =A0 =A0{
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0error ("new declaration %q#D", newdecl);
>> @@ -2250,6 +2272,16 @@ duplicate_decls (tree newdecl, tree olddecl, bool
>> =A0 else if (DECL_PRESERVE_P (newdecl))
>> =A0 =A0 DECL_PRESERVE_P (olddecl) =3D 1;
>>
>> + =A0/* If the olddecl is a version, so is the newdecl. =A0*/
>> + =A0if (TREE_CODE (newdecl) =3D=3D FUNCTION_DECL
>> + =A0 =A0 =A0&& DECL_FUNCTION_VERSIONED (olddecl))
>> + =A0 =A0{
>> + =A0 =A0 =A0DECL_FUNCTION_VERSIONED (newdecl) =3D 1;
>> + =A0 =A0 =A0/* Record that newdecl is not a valid version and has
>> + =A0 =A0 =A0 =A0been deleted. =A0*/
>> + =A0 =A0 =A0mark_delete_decl_version (newdecl);
>> + =A0 =A0}
>> +
>> =A0 if (TREE_CODE (newdecl) =3D=3D FUNCTION_DECL)
>> =A0 =A0 {
>> =A0 =A0 =A0 int function_size;
>> @@ -4512,6 +4544,10 @@ start_decl (const cp_declarator *declarator,
>> =A0 /* Enter this declaration into the symbol table. =A0*/
>> =A0 decl =3D maybe_push_decl (decl);
>>
>> + =A0/* If this decl is a function version and not the default, its asse=
mbler
>> + =A0 =A0 name has to be changed. =A0*/
>> + =A0version_assembler_name (decl);
>> +
>> =A0 if (processing_template_decl)
>> =A0 =A0 decl =3D push_template_decl (decl);
>> =A0 if (decl =3D=3D error_mark_node)
>> @@ -13019,6 +13055,10 @@ start_function (cp_decl_specifier_seq *declspec=
s,
>> =A0 =A0 gcc_assert (same_type_p (TREE_TYPE (TREE_TYPE (decl1)),
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 integer_type_nod=
e));
>>
>> + =A0/* If this decl is a function version and not the default, its asse=
mbler
>> + =A0 =A0 name has to be changed. =A0*/
>> + =A0version_assembler_name (decl1);
>> +
>> =A0 start_preparsed_function (decl1, attrs, /*flags=3D*/SF_DEFAULT);
>>
>> =A0 return 1;
>> @@ -13960,6 +14000,11 @@ cxx_comdat_group (tree decl)
>> =A0 =A0 =A0 =A0 =A0 =A0break;
>> =A0 =A0 =A0 =A0}
>> =A0 =A0 =A0 name =3D DECL_ASSEMBLER_NAME (decl);
>> + =A0 =A0 =A0if (TREE_CODE (decl) =3D=3D FUNCTION_DECL
>> + =A0 =A0 =A0 =A0 && DECL_FUNCTION_VERSIONED (decl))
>> + =A0 =A0 =A0 name =3D DECL_NAME (decl);
>> + =A0 =A0 =A0else
>> + =A0 =A0 =A0 =A0name =3D DECL_ASSEMBLER_NAME (decl);
>> =A0 =A0 }
>>
>> =A0 return name;
>> Index: cp/semantics.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- cp/semantics.c =A0 =A0 =A0(revision 184971)
>> +++ cp/semantics.c =A0 =A0 =A0(working copy)
>> @@ -3783,8 +3783,11 @@ expand_or_defer_fn_1 (tree fn)
>> =A0 =A0 =A0 /* If the user wants us to keep all inline functions, then m=
ark
>> =A0 =A0 =A0 =A0 this function as needed so that finish_file will make su=
re to
>> =A0 =A0 =A0 =A0 output it later. =A0Similarly, all dllexport'd functions=
 must
>> - =A0 =A0 =A0 =A0be emitted; there may be callers in other DLLs. =A0*/
>> - =A0 =A0 =A0if ((flag_keep_inline_functions
>> + =A0 =A0 =A0 =A0be emitted; there may be callers in other DLLs.
>> + =A0 =A0 =A0 =A0Also, mark this function as needed if it is marked inli=
ne but
>> + =A0 =A0 =A0 =A0is a multi-versioned function. =A0*/
>> + =A0 =A0 =A0if (((flag_keep_inline_functions
>> + =A0 =A0 =A0 =A0 =A0 || DECL_FUNCTION_VERSIONED (fn))
>> =A0 =A0 =A0 =A0 =A0 && DECL_DECLARED_INLINE_P (fn)
>> =A0 =A0 =A0 =A0 =A0 && !DECL_REALLY_EXTERN (fn))
>> =A0 =A0 =A0 =A0 =A0|| (flag_keep_inline_dllexport
>> Index: cp/decl2.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- cp/decl2.c =A0(revision 184971)
>> +++ cp/decl2.c =A0(working copy)
>> @@ -53,6 +53,7 @@ along with GCC; see the file COPYING3. =A0If not see
>> =A0#include "splay-tree.h"
>> =A0#include "langhooks.h"
>> =A0#include "c-family/c-ada-spec.h"
>> +#include "multiversion.h"
>>
>> =A0extern cpp_reader *parse_in;
>>
>> @@ -674,9 +675,13 @@ check_classfn (tree ctype, tree function, tree tem
>> =A0 =A0 =A0 =A0 =A0if (is_template !=3D (TREE_CODE (fndecl) =3D=3D TEMPL=
ATE_DECL))
>> =A0 =A0 =A0 =A0 =A0 =A0continue;
>>
>> + =A0 =A0 =A0 =A0 /* While finding a match, same types and params are no=
t enough
>> + =A0 =A0 =A0 =A0 =A0 =A0if the function is versioned. =A0Also check ver=
sion ("targetv")
>> + =A0 =A0 =A0 =A0 =A0 =A0attributes. =A0*/
>> =A0 =A0 =A0 =A0 =A0if (same_type_p (TREE_TYPE (TREE_TYPE (function)),
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 TREE_TYPE (TREE_TYPE=
 (fndecl)))
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0&& compparms (p1, p2)
>> + =A0 =A0 =A0 =A0 =A0 =A0 && !has_different_version_attributes (function=
, fndecl)
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0&& (!is_template
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0|| comp_template_parms (template_parm=
s,
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0DECL_TEMPLATE_PARMS (fndecl)))
>> Index: cp/call.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- cp/call.c =A0 (revision 184971)
>> +++ cp/call.c =A0 (working copy)
>> @@ -41,6 +41,7 @@ along with GCC; see the file COPYING3. =A0If not see
>> =A0#include "langhooks.h"
>> =A0#include "c-family/c-objc.h"
>> =A0#include "timevar.h"
>> +#include "multiversion.h"
>>
>> =A0/* The various kinds of conversion. =A0*/
>>
>> @@ -6730,6 +6731,17 @@ build_over_call (struct z_candidate *cand, int fla
>> =A0 if (!already_used)
>> =A0 =A0 mark_used (fn);
>>
>> + =A0/* For a call to a multi-versioned function, the call should actual=
ly be to
>> + =A0 =A0 the dispatcher. =A0*/
>> + =A0if (DECL_FUNCTION_VERSIONED (fn))
>> + =A0 =A0{
>> + =A0 =A0 =A0tree ifunc_decl;
>> + =A0 =A0 =A0ifunc_decl =3D get_ifunc_for_version (fn);
>> + =A0 =A0 =A0gcc_assert (ifunc_decl !=3D NULL);
>> + =A0 =A0 =A0return build_call_expr_loc_array (UNKNOWN_LOCATION, ifunc_d=
ecl,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 nargs, argarray);
>> + =A0 =A0}
>> +
>> =A0 if (DECL_VINDEX (fn) && (flags & LOOKUP_NONVIRTUAL) =3D=3D 0)
>> =A0 =A0 {
>> =A0 =A0 =A0 tree t;
>> @@ -7980,6 +7992,30 @@ joust (struct z_candidate *cand1, struct z_candida
>> =A0 size_t i;
>> =A0 size_t len;
>>
>> + =A0/* For Candidates of a multi-versioned function, the one marked def=
ault
>> + =A0 =A0 wins. =A0This is because the default decl is used as key to ag=
gregate
>> + =A0 =A0 all the other versions provided for it in multiversion.c. =A0W=
hen
>> + =A0 =A0 generating the actual call, the appropriate dispatcher is crea=
ted
>> + =A0 =A0 to call the right function version at run-time. =A0*/
>> +
>> + =A0if ((TREE_CODE (cand1->fn) =3D=3D FUNCTION_DECL
>> + =A0 =A0 =A0 && DECL_FUNCTION_VERSIONED (cand1->fn))
>> + =A0 =A0 =A0||(TREE_CODE (cand2->fn) =3D=3D FUNCTION_DECL
>> + =A0 =A0 =A0 =A0&& DECL_FUNCTION_VERSIONED (cand2->fn)))
>> + =A0 =A0{
>> + =A0 =A0 =A0if (is_default_function (cand1->fn))
>> + =A0 =A0 =A0 {
>> + =A0 =A0 =A0 =A0 =A0mark_used (cand2->fn);
>> + =A0 =A0 =A0 =A0 return 1;
>> + =A0 =A0 =A0 }
>> + =A0 =A0 =A0if (is_default_function (cand2->fn))
>> + =A0 =A0 =A0 {
>> + =A0 =A0 =A0 =A0 =A0mark_used (cand1->fn);
>> + =A0 =A0 =A0 =A0 return -1;
>> + =A0 =A0 =A0 }
>> + =A0 =A0 =A0return 0;
>> + =A0 =A0}
>> +
>> =A0 /* Candidates that involve bad conversions are always worse than tho=
se
>> =A0 =A0 =A0that don't. =A0*/
>> =A0 if (cand1->viable > cand2->viable)
>> Index: timevar.def
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- timevar.def (revision 184971)
>> +++ timevar.def (working copy)
>> @@ -253,6 +253,7 @@ DEFTIMEVAR (TV_TREE_IFCOMBINE =A0 =A0 =A0 =A0, "tree=
 if-co
>> =A0DEFTIMEVAR (TV_TREE_UNINIT =A0 =A0 =A0 =A0 =A0 , "uninit var analysis=
")
>> =A0DEFTIMEVAR (TV_PLUGIN_INIT =A0 =A0 =A0 =A0 =A0 , "plugin initializati=
on")
>> =A0DEFTIMEVAR (TV_PLUGIN_RUN =A0 =A0 =A0 =A0 =A0 =A0, "plugin execution")
>> +DEFTIMEVAR (TV_MULTIVERSION_DISPATCH , "multiversion dispatch")
>>
>> =A0/* Everything else in rest_of_compilation not included above. =A0*/
>> =A0DEFTIMEVAR (TV_EARLY_LOCAL =A0 =A0 =A0 =A0 =A0, "early local passes")
>> Index: varasm.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- varasm.c =A0 =A0(revision 184971)
>> +++ varasm.c =A0 =A0(working copy)
>> @@ -5755,6 +5755,8 @@ finish_aliases_1 (void)
>> =A0 =A0 =A0 =A0}
>> =A0 =A0 =A0 else if (! (p->emitted_diags & ALIAS_DIAG_TO_EXTERN)
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 && DECL_EXTERNAL (target_decl)
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0&& (!TREE_CODE (target_decl) =3D=3D FUNCTIO=
N_DECL
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0|| !DECL_STRUCT_FUNCTION (target_de=
cl))
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 /* We use local aliases for C++ thunks to fo=
rce the tailcall
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0to bind locally. =A0This is a hack - =
to keep it working do
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0the following (which is not strictly =
correct). =A0*/
>> Index: Makefile.in
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- Makefile.in (revision 184971)
>> +++ Makefile.in (working copy)
>> @@ -1298,6 +1298,7 @@ OBJS =3D \
>> =A0 =A0 =A0 =A0mcf.o \
>> =A0 =A0 =A0 =A0mode-switching.o \
>> =A0 =A0 =A0 =A0modulo-sched.o \
>> + =A0 =A0 =A0 multiversion.o \
>> =A0 =A0 =A0 =A0omega.o \
>> =A0 =A0 =A0 =A0omp-low.o \
>> =A0 =A0 =A0 =A0optabs.o \
>> @@ -3030,6 +3031,11 @@ ree.o : ree.c $(CONFIG_H) $(SYSTEM_H) coretypes.h
>> =A0 =A0$(DF_H) $(TIMEVAR_H) tree-pass.h $(RECOG_H) $(EXPR_H) \
>> =A0 =A0$(REGS_H) $(TREE_H) $(TM_P_H) insn-config.h $(INSN_ATTR_H) $(DIAG=
NOSTIC_CORE_H) \
>> =A0 =A0$(TARGET_H) $(OPTABS_H) insn-codes.h rtlhooks-def.h $(PARAMS_H) $=
(CGRAPH_H)
>> +multiversion.o : multiversion.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(T=
M_H) \
>> + =A0 $(TREE_H) langhooks.h $(TREE_INLINE_H) $(FLAGS_H) $(CGRAPH_H) intl=
.h \
>> + =A0 $(DIAGNOSTIC_H) $(FIBHEAP_H) $(PARAMS_H) $(TIMEVAR_H) tree-pass.h \
>> + =A0 $(HASHTAB_H) $(COVERAGE_H) $(GGC_H) $(TREE_FLOW_H) $(RTL_H) $(IPA_=
PROP_H) \
>> + =A0 $(BASIC_BLOCK_H) $(TOPLEV_H) $(TREE_DUMP_H) ipa-inline.h
>> =A0cprop.o : cprop.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H=
) \
>> =A0 =A0$(REGS_H) hard-reg-set.h $(FLAGS_H) insn-config.h $(GGC_H) \
>> =A0 =A0$(RECOG_H) $(EXPR_H) $(BASIC_BLOCK_H) $(FUNCTION_H) output.h topl=
ev.h $(DIAGNOSTIC_CORE_H) \
>> Index: passes.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- passes.c =A0 =A0(revision 184971)
>> +++ passes.c =A0 =A0(working copy)
>> @@ -1190,6 +1190,7 @@ init_optimization_passes (void)
>> =A0 NEXT_PASS (pass_build_cfg);
>> =A0 NEXT_PASS (pass_warn_function_return);
>> =A0 NEXT_PASS (pass_build_cgraph_edges);
>> + =A0NEXT_PASS (pass_dispatch_versions);
>> =A0 *p =3D NULL;
>>
>> =A0 /* Interprocedural optimization passes. =A0*/
>> Index: config/i386/i386.c
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- config/i386/i386.c =A0(revision 184971)
>> +++ config/i386/i386.c =A0(working copy)
>> @@ -27446,6 +27473,593 @@ ix86_init_mmx_sse_builtins (void)
>> =A0 =A0 }
>> =A0}
>>
>> +/* This adds a condition to the basic_block NEW_BB in function FUNCTION=
_DECL
>> + =A0 to return a pointer to VERSION_DECL if the outcome of the function
>> + =A0 PREDICATE_DECL is true. =A0This function will be called during ver=
sion
>> + =A0 dispatch to decide which function version to execute. =A0It return=
s the
>> + =A0 basic block at the end to which more conditions can be added. =A0*/
>> +
>> +static basic_block
>> +add_condition_to_bb (tree function_decl, tree version_decl,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0basic_block new_bb, tree predic=
ate_decl)
>> +{
>> + =A0gimple return_stmt;
>> + =A0tree convert_expr, result_var;
>> + =A0gimple convert_stmt;
>> + =A0gimple call_cond_stmt;
>> + =A0gimple if_else_stmt;
>> +
>> + =A0basic_block bb1, bb2, bb3;
>> + =A0edge e12, e23;
>> +
>> + =A0tree cond_var;
>> + =A0gimple_seq gseq;
>> +
>> + =A0tree old_current_function_decl;
>> +
>> + =A0old_current_function_decl =3D current_function_decl;
>> + =A0push_cfun (DECL_STRUCT_FUNCTION (function_decl));
>> + =A0current_function_decl =3D function_decl;
>> +
>> + =A0gcc_assert (new_bb !=3D NULL);
>> + =A0gseq =3D bb_seq (new_bb);
>> +
>> +
>> + =A0convert_expr =3D build1 (CONVERT_EXPR, ptr_type_node,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0build_fold_addr_expr (v=
ersion_decl));
>> + =A0result_var =3D create_tmp_var (ptr_type_node, NULL);
>> + =A0convert_stmt =3D gimple_build_assign (result_var, convert_expr);
>> + =A0return_stmt =3D gimple_build_return (result_var);
>> +
>> + =A0if (predicate_decl =3D=3D NULL_TREE)
>> + =A0 =A0{
>> + =A0 =A0 =A0gimple_seq_add_stmt (&gseq, convert_stmt);
>> + =A0 =A0 =A0gimple_seq_add_stmt (&gseq, return_stmt);
>> + =A0 =A0 =A0set_bb_seq (new_bb, gseq);
>> + =A0 =A0 =A0gimple_set_bb (convert_stmt, new_bb);
>> + =A0 =A0 =A0gimple_set_bb (return_stmt, new_bb);
>> + =A0 =A0 =A0pop_cfun ();
>> + =A0 =A0 =A0current_function_decl =3D old_current_function_decl;
>> + =A0 =A0 =A0return new_bb;
>> + =A0 =A0}
>> +
>> + =A0cond_var =3D create_tmp_var (integer_type_node, NULL);
>> + =A0call_cond_stmt =3D gimple_build_call (predicate_decl, 0);
>> + =A0gimple_call_set_lhs (call_cond_stmt, cond_var);
>> +
>> + =A0gimple_set_block (call_cond_stmt, DECL_INITIAL (function_decl));
>> + =A0gimple_set_bb (call_cond_stmt, new_bb);
>> + =A0gimple_seq_add_stmt (&gseq, call_cond_stmt);
>> +
>> + =A0if_else_stmt =3D gimple_build_cond (GT_EXPR, cond_var,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 in=
teger_zero_node,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 NU=
LL_TREE, NULL_TREE);
>> + =A0gimple_set_block (if_else_stmt, DECL_INITIAL (function_decl));
>> + =A0gimple_set_bb (if_else_stmt, new_bb);
>> + =A0gimple_seq_add_stmt (&gseq, if_else_stmt);
>> +
>> + =A0gimple_seq_add_stmt (&gseq, convert_stmt);
>> + =A0gimple_seq_add_stmt (&gseq, return_stmt);
>> + =A0set_bb_seq (new_bb, gseq);
>> +
>> + =A0bb1 =3D new_bb;
>> + =A0e12 =3D split_block (bb1, if_else_stmt);
>> + =A0bb2 =3D e12->dest;
>> + =A0e12->flags &=3D ~EDGE_FALLTHRU;
>> + =A0e12->flags |=3D EDGE_TRUE_VALUE;
>> +
>> + =A0e23 =3D split_block (bb2, return_stmt);
>> +
>> + =A0gimple_set_bb (convert_stmt, bb2);
>> + =A0gimple_set_bb (return_stmt, bb2);
>> +
>> + =A0bb3 =3D e23->dest;
>> + =A0make_edge (bb1, bb3, EDGE_FALSE_VALUE);
>> +
>> + =A0remove_edge (e23);
>> + =A0make_edge (bb2, EXIT_BLOCK_PTR, 0);
>> +
>> + =A0rebuild_cgraph_edges ();
>> +
>> + =A0pop_cfun ();
>> + =A0current_function_decl =3D old_current_function_decl;
>> +
>> + =A0return bb3;
>> +}
>> +
>> +/* This parses the attribute arguments to targetv in DECL and determines
>> + =A0 the right builtin to use to match the platform specification.
>> + =A0 For now, only one target argument ("arch=3D") is allowed. =A0*/
>> +
>> +static enum ix86_builtins
>> +get_builtin_code_for_version (tree decl)
>> +{
>> + =A0tree attrs;
>> + =A0struct cl_target_option cur_target;
>> + =A0tree target_node;
>> + =A0struct cl_target_option *new_target;
>> + =A0enum ix86_builtins builtin_code =3D IX86_BUILTIN_MAX;
>> +
>> + =A0attrs =3D lookup_attribute ("targetv", DECL_ATTRIBUTES (decl));
>> + =A0gcc_assert (attrs !=3D NULL);
>> +
>> + =A0cl_target_option_save (&cur_target, &global_options);
>> +
>> + =A0target_node =3D ix86_valid_target_attribute_tree
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 (TREE_VALUE (TREE_VALUE (attrs)));
>> +
>> + =A0gcc_assert (target_node);
>> + =A0new_target =3D TREE_TARGET_OPTION (target_node);
>> + =A0gcc_assert (new_target);
>> +
>> + =A0if (new_target->arch_specified && new_target->arch > 0)
>> + =A0 =A0{
>> + =A0 =A0 =A0switch (new_target->arch)
>> + =A0 =A0 =A0 =A0{
>> + =A0 =A0 =A0 case 1:
>> + =A0 =A0 =A0 case 2:
>> + =A0 =A0 =A0 case 3:
>> + =A0 =A0 =A0 case 4:
>> + =A0 =A0 =A0 case 5:
>> + =A0 =A0 =A0 case 6:
>> + =A0 =A0 =A0 case 7:
>> + =A0 =A0 =A0 case 8:
>> + =A0 =A0 =A0 case 9:
>> + =A0 =A0 =A0 case 10:
>> + =A0 =A0 =A0 case 11:
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_INTEL;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 case 12:
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_INTEL_CORE2;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 case 13:
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_INTEL_COREI7;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 case 14:
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_INTEL_ATOM;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 case 15:
>> + =A0 =A0 =A0 case 16:
>> + =A0 =A0 =A0 case 17:
>> + =A0 =A0 =A0 case 18:
>> + =A0 =A0 =A0 case 19:
>> + =A0 =A0 =A0 case 20:
>> + =A0 =A0 =A0 case 21:
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_AMD;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 case 22:
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_AMDFAM10H;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 case 23:
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_AMDFAM15H_BDVER1;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 case 24:
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_AMDFAM15H_BDVER2;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 case 25: /* What is btver1 ? */
>> + =A0 =A0 =A0 =A0 builtin_code =3D IX86_BUILTIN_CPU_IS_AMD;
>> + =A0 =A0 =A0 =A0 break;
>> + =A0 =A0 =A0 }
>> + =A0 =A0}
>> +
>> + =A0cl_target_option_restore (&global_options, &cur_target);
>> + =A0if (builtin_code =3D=3D IX86_BUILTIN_MAX)
>> + =A0 =A0 =A0error_at (DECL_SOURCE_LOCATION (decl),
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 "No dispatcher found for the versioning at=
tributes");
>> +
>> + =A0return builtin_code;
>> +}
>> +
>> +/* This is the target hook to generate the dispatch function for
>> + =A0 multi-versioned functions. =A0DISPATCH_DECL is the function which =
will
>> + =A0 contain the dispatch logic. =A0FNDECLS are the function choices for
>> + =A0 dispatch, and is a tree chain. =A0EMPTY_BB is the basic block poin=
ter
>> + =A0 in DISPATCH_DECL in which the dispatch code is generated. =A0*/
>> +
>> +static int
>> +ix86_dispatch_version (tree dispatch_decl,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0void *fndecls_p,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0basic_block *empty_bb)
>> +{
>> + =A0tree default_decl;
>> + =A0gimple ifunc_cpu_init_stmt;
>> + =A0gimple_seq gseq;
>> + =A0tree old_current_function_decl;
>> + =A0int ix;
>> + =A0tree ele;
>> + =A0VEC (tree, heap) *fndecls;
>> +
>> + =A0gcc_assert (dispatch_decl !=3D NULL
>> + =A0 =A0 =A0 =A0 =A0 =A0 && fndecls_p !=3D NULL
>> + =A0 =A0 =A0 =A0 =A0 =A0 && empty_bb !=3D NULL);
>> +
>> + =A0/*fndecls_p is actually a vector. =A0*/
>> + =A0fndecls =3D (VEC (tree, heap) *)fndecls_p;
>> +
>> + =A0/* Atleast one more version other than the default. =A0*/
>> + =A0gcc_assert (VEC_length (tree, fndecls) >=3D 2);
>> +
>> + =A0/* The first version in the vector is the default decl. =A0*/
>> + =A0default_decl =3D VEC_index (tree, fndecls, 0);
>> +
>> + =A0old_current_function_decl =3D current_function_decl;
>> + =A0push_cfun (DECL_STRUCT_FUNCTION (dispatch_decl));
>> + =A0current_function_decl =3D dispatch_decl;
>> +
>> + =A0gseq =3D bb_seq (*empty_bb);
>> + =A0ifunc_cpu_init_stmt =3D gimple_build_call_vec (
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ix86_builtins [(int) IX86_BUIL=
TIN_CPU_INIT], NULL);
>> + =A0gimple_seq_add_stmt (&gseq, ifunc_cpu_init_stmt);
>> + =A0gimple_set_bb (ifunc_cpu_init_stmt, *empty_bb);
>> + =A0set_bb_seq (*empty_bb, gseq);
>> +
>> + =A0pop_cfun ();
>> + =A0current_function_decl =3D old_current_function_decl;
>> +
>> +
>> + =A0for (ix =3D 1; VEC_iterate (tree, fndecls, ix, ele); ++ix)
>> + =A0 =A0{
>> + =A0 =A0 =A0tree version_decl =3D ele;
>> + =A0 =A0 =A0/* Get attribute string, parse it and find the right predic=
ate decl.
>> + =A0 =A0 =A0 =A0 The predicate function could be a lengthy combination =
of many
>> + =A0 =A0 =A0 =A0features, like arch-type and various isa-variants. =A0F=
or now, only
>> + =A0 =A0 =A0 =A0check the arch-type. =A0*/
>> + =A0 =A0 =A0tree predicate_decl =3D ix86_builtins [
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 get_builtin_code_for_versi=
on (version_decl)];
>> + =A0 =A0 =A0*empty_bb =3D add_condition_to_bb (dispatch_decl, version_d=
ecl, *empty_bb,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0predicate_decl);
>> +
>> + =A0 =A0}
>> + =A0/* dispatch default version at the end. =A0*/
>> + =A0*empty_bb =3D add_condition_to_bb (dispatch_decl, default_decl, *em=
pty_bb,
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0NUL=
L);
>> + =A0return 0;
>> +}
>>
>> @@ -38610,6 +39269,12 @@ ix86_autovectorize_vector_sizes (void)
>> =A0#undef TARGET_BUILD_BUILTIN_VA_LIST
>> =A0#define TARGET_BUILD_BUILTIN_VA_LIST ix86_build_builtin_va_list
>>
>> +#undef TARGET_DISPATCH_VERSION
>> +#define TARGET_DISPATCH_VERSION ix86_dispatch_version
>> +
>> =A0#undef TARGET_ENUM_VA_LIST_P
>> =A0#define TARGET_ENUM_VA_LIST_P ix86_enum_va_list
>>
>> Index: testsuite/g++.dg/mv1.C
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>> --- testsuite/g++.dg/mv1.C =A0 =A0 =A0(revision 0)
>> +++ testsuite/g++.dg/mv1.C =A0 =A0 =A0(revision 0)
>> @@ -0,0 +1,23 @@
>> +/* Simple test case to check if Multiversioning works. =A0*/
>> +/* { dg-do run } */
>> +/* { dg-options "-O2" } */
>> +
>> +int foo ();
>> +int foo () __attribute__ ((targetv("arch=3Dcorei7")));
>> +
>> +int main ()
>> +{
>> + =A0int (*p)() =3D &foo;
>> + =A0return foo () + (*p)();
>> +}
>> +
>> +int foo ()
>> +{
>> + =A0return 0;
>> +}
>> +
>> +int __attribute__ ((targetv("arch=3Dcorei7")))
>> +foo ()
>> +{
>> + =A0return 0;
>> +}
>>
>>
>> --
>> This patch is available for review at http://codereview.appspot.com/5752=
064