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/* Pass for parsing functions with multiple target attributes.
Contributed by Evgeny Stupachenko <evstupac@gmail.com>
Copyright (C) 2015-2018 Free Software Foundation, Inc.
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. See 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. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "tree.h"
#include "stringpool.h"
#include "gimple.h"
#include "diagnostic-core.h"
#include "gimple-ssa.h"
#include "cgraph.h"
#include "tree-pass.h"
#include "target.h"
#include "attribs.h"
#include "pretty-print.h"
#include "gimple-iterator.h"
#include "gimple-walk.h"
#include "tree-inline.h"
#include "intl.h"
/* Walker callback that replaces all FUNCTION_DECL of a function that's
going to be versioned. */
static tree
replace_function_decl (tree *op, int *walk_subtrees, void *data)
{
struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
cgraph_function_version_info *info = (cgraph_function_version_info *)wi->info;
if (TREE_CODE (*op) == FUNCTION_DECL
&& info->this_node->decl == *op)
{
*op = info->dispatcher_resolver;
*walk_subtrees = 0;
}
return NULL;
}
/* If the call in NODE has multiple target attribute with multiple fields,
replace it with dispatcher call and create dispatcher (once). */
static void
create_dispatcher_calls (struct cgraph_node *node)
{
ipa_ref *ref;
if (!DECL_FUNCTION_VERSIONED (node->decl)
|| !is_function_default_version (node->decl))
return;
if (!targetm.has_ifunc_p ())
{
error_at (DECL_SOURCE_LOCATION (node->decl),
"the call requires ifunc, which is not"
" supported by this target");
return;
}
else if (!targetm.get_function_versions_dispatcher)
{
error_at (DECL_SOURCE_LOCATION (node->decl),
"target does not support function version dispatcher");
return;
}
tree idecl = targetm.get_function_versions_dispatcher (node->decl);
if (!idecl)
{
error_at (DECL_SOURCE_LOCATION (node->decl),
"default %<target_clones%> attribute was not set");
return;
}
cgraph_node *inode = cgraph_node::get (idecl);
gcc_assert (inode);
tree resolver_decl = targetm.generate_version_dispatcher_body (inode);
/* Update aliases. */
inode->alias = true;
inode->alias_target = resolver_decl;
if (!inode->analyzed)
inode->resolve_alias (cgraph_node::get (resolver_decl));
auto_vec<cgraph_edge *> edges_to_redirect;
auto_vec<ipa_ref *> references_to_redirect;
for (unsigned i = 0; node->iterate_referring (i, ref); i++)
references_to_redirect.safe_push (ref);
/* We need to remember NEXT_CALLER as it could be modified in the loop. */
for (cgraph_edge *e = node->callers; e ; e = e->next_caller)
edges_to_redirect.safe_push (e);
if (!edges_to_redirect.is_empty () || !references_to_redirect.is_empty ())
{
/* Redirect edges. */
unsigned i;
cgraph_edge *e;
FOR_EACH_VEC_ELT (edges_to_redirect, i, e)
{
e->redirect_callee (inode);
e->redirect_call_stmt_to_callee ();
}
/* Redirect references. */
FOR_EACH_VEC_ELT (references_to_redirect, i, ref)
{
if (ref->use == IPA_REF_ADDR)
{
struct walk_stmt_info wi;
memset (&wi, 0, sizeof (wi));
wi.info = (void *)node->function_version ();
if (dyn_cast<varpool_node *> (ref->referring))
{
hash_set<tree> visited_nodes;
walk_tree (&DECL_INITIAL (ref->referring->decl),
replace_function_decl, &wi, &visited_nodes);
}
else
{
gimple_stmt_iterator it = gsi_for_stmt (ref->stmt);
if (ref->referring->decl != resolver_decl)
walk_gimple_stmt (&it, NULL, replace_function_decl, &wi);
}
symtab_node *source = ref->referring;
ref->remove_reference ();
source->create_reference (inode, IPA_REF_ADDR);
}
else if (ref->use == IPA_REF_ALIAS)
{
symtab_node *source = ref->referring;
ref->remove_reference ();
source->create_reference (inode, IPA_REF_ALIAS);
source->add_to_same_comdat_group (inode);
}
else
gcc_unreachable ();
}
}
symtab->change_decl_assembler_name (node->decl,
clone_function_name (node->decl,
"default"));
/* FIXME: copy of cgraph_node::make_local that should be cleaned up
in next stage1. */
node->make_decl_local ();
node->set_section (NULL);
node->set_comdat_group (NULL);
node->externally_visible = false;
node->forced_by_abi = false;
node->set_section (NULL);
node->unique_name = ((node->resolution == LDPR_PREVAILING_DEF_IRONLY
|| node->resolution == LDPR_PREVAILING_DEF_IRONLY_EXP)
&& !flag_incremental_link);
node->resolution = LDPR_PREVAILING_DEF_IRONLY;
DECL_ARTIFICIAL (node->decl) = 1;
node->force_output = true;
}
/* Return length of attribute names string,
if arglist chain > 1, -1 otherwise. */
static int
get_attr_len (tree arglist)
{
tree arg;
int str_len_sum = 0;
int argnum = 0;
for (arg = arglist; arg; arg = TREE_CHAIN (arg))
{
const char *str = TREE_STRING_POINTER (TREE_VALUE (arg));
size_t len = strlen (str);
str_len_sum += len + 1;
for (const char *p = strchr (str, ','); p; p = strchr (p + 1, ','))
argnum++;
argnum++;
}
if (argnum <= 1)
return -1;
return str_len_sum;
}
/* Create string with attributes separated by comma.
Return number of attributes. */
static int
get_attr_str (tree arglist, char *attr_str)
{
tree arg;
size_t str_len_sum = 0;
int argnum = 0;
for (arg = arglist; arg; arg = TREE_CHAIN (arg))
{
const char *str = TREE_STRING_POINTER (TREE_VALUE (arg));
size_t len = strlen (str);
for (const char *p = strchr (str, ','); p; p = strchr (p + 1, ','))
argnum++;
memcpy (attr_str + str_len_sum, str, len);
attr_str[str_len_sum + len] = TREE_CHAIN (arg) ? ',' : '\0';
str_len_sum += len + 1;
argnum++;
}
return argnum;
}
/* Return number of attributes separated by comma and put them into ARGS.
If there is no DEFAULT attribute return -1. If there is an empty
string in attribute return -2. */
static int
separate_attrs (char *attr_str, char **attrs, int attrnum)
{
int i = 0;
int default_count = 0;
for (char *attr = strtok (attr_str, ",");
attr != NULL; attr = strtok (NULL, ","))
{
if (strcmp (attr, "default") == 0)
{
default_count++;
continue;
}
attrs[i++] = attr;
}
if (default_count == 0)
return -1;
else if (i + default_count < attrnum)
return -2;
return i;
}
/* Return true if symbol is valid in assembler name. */
static bool
is_valid_asm_symbol (char c)
{
if ('a' <= c && c <= 'z')
return true;
if ('A' <= c && c <= 'Z')
return true;
if ('0' <= c && c <= '9')
return true;
if (c == '_')
return true;
return false;
}
/* Replace all not valid assembler symbols with '_'. */
static void
create_new_asm_name (char *old_asm_name, char *new_asm_name)
{
int i;
int old_name_len = strlen (old_asm_name);
/* Replace all not valid assembler symbols with '_'. */
for (i = 0; i < old_name_len; i++)
if (!is_valid_asm_symbol (old_asm_name[i]))
new_asm_name[i] = '_';
else
new_asm_name[i] = old_asm_name[i];
new_asm_name[old_name_len] = '\0';
}
/* Creates target clone of NODE. */
static cgraph_node *
create_target_clone (cgraph_node *node, bool definition, char *name)
{
cgraph_node *new_node;
if (definition)
{
new_node = node->create_version_clone_with_body (vNULL, NULL,
NULL, false,
NULL, NULL,
name);
new_node->force_output = true;
}
else
{
tree new_decl = copy_node (node->decl);
new_node = cgraph_node::get_create (new_decl);
/* Generate a new name for the new version. */
symtab->change_decl_assembler_name (new_node->decl,
clone_function_name (node->decl,
name));
}
return new_node;
}
/* If the function in NODE has multiple target attributes
create the appropriate clone for each valid target attribute. */
static bool
expand_target_clones (struct cgraph_node *node, bool definition)
{
int i;
/* Parsing target attributes separated by comma. */
tree attr_target = lookup_attribute ("target_clones",
DECL_ATTRIBUTES (node->decl));
/* No targets specified. */
if (!attr_target)
return false;
tree arglist = TREE_VALUE (attr_target);
int attr_len = get_attr_len (arglist);
/* No need to clone for 1 target attribute. */
if (attr_len == -1)
{
warning_at (DECL_SOURCE_LOCATION (node->decl),
0,
"single %<target_clones%> attribute is ignored");
return false;
}
if (node->definition
&& !tree_versionable_function_p (node->decl))
{
error_at (DECL_SOURCE_LOCATION (node->decl),
"clones for %<target_clones%> attribute cannot be created");
const char *reason = NULL;
if (lookup_attribute ("noclone", DECL_ATTRIBUTES (node->decl)))
reason = G_("function %q+F can never be copied "
"because it has %<noclone%> attribute");
else
reason = copy_forbidden (DECL_STRUCT_FUNCTION (node->decl));
if (reason)
inform (DECL_SOURCE_LOCATION (node->decl), reason, node->decl);
return false;
}
char *attr_str = XNEWVEC (char, attr_len);
int attrnum = get_attr_str (arglist, attr_str);
char **attrs = XNEWVEC (char *, attrnum);
attrnum = separate_attrs (attr_str, attrs, attrnum);
if (attrnum == -1)
{
error_at (DECL_SOURCE_LOCATION (node->decl),
"default target was not set");
XDELETEVEC (attrs);
XDELETEVEC (attr_str);
return false;
}
else if (attrnum == -2)
{
error_at (DECL_SOURCE_LOCATION (node->decl),
"an empty string cannot be in %<target_clones%> attribute");
XDELETEVEC (attrs);
XDELETEVEC (attr_str);
return false;
}
cgraph_function_version_info *decl1_v = NULL;
cgraph_function_version_info *decl2_v = NULL;
cgraph_function_version_info *before = NULL;
cgraph_function_version_info *after = NULL;
decl1_v = node->function_version ();
if (decl1_v == NULL)
decl1_v = node->insert_new_function_version ();
before = decl1_v;
DECL_FUNCTION_VERSIONED (node->decl) = 1;
for (i = 0; i < attrnum; i++)
{
char *attr = attrs[i];
char *suffix = XNEWVEC (char, strlen (attr) + 1);
create_new_asm_name (attr, suffix);
/* Create new target clone. */
cgraph_node *new_node = create_target_clone (node, definition, suffix);
new_node->local.local = false;
XDELETEVEC (suffix);
/* Set new attribute for the clone. */
tree attributes = make_attribute ("target", attr,
DECL_ATTRIBUTES (new_node->decl));
DECL_ATTRIBUTES (new_node->decl) = attributes;
location_t saved_loc = input_location;
input_location = DECL_SOURCE_LOCATION (node->decl);
if (!targetm.target_option.valid_attribute_p (new_node->decl, NULL,
TREE_VALUE (attributes),
0))
return false;
input_location = saved_loc;
decl2_v = new_node->function_version ();
if (decl2_v != NULL)
continue;
decl2_v = new_node->insert_new_function_version ();
/* Chain decl2_v and decl1_v. All semantically identical versions
will be chained together. */
after = decl2_v;
while (before->next != NULL)
before = before->next;
while (after->prev != NULL)
after = after->prev;
before->next = after;
after->prev = before;
DECL_FUNCTION_VERSIONED (new_node->decl) = 1;
}
XDELETEVEC (attrs);
XDELETEVEC (attr_str);
/* Setting new attribute to initial function. */
tree attributes = make_attribute ("target", "default",
DECL_ATTRIBUTES (node->decl));
DECL_ATTRIBUTES (node->decl) = attributes;
node->local.local = false;
location_t saved_loc = input_location;
input_location = DECL_SOURCE_LOCATION (node->decl);
bool ret
= targetm.target_option.valid_attribute_p (node->decl, NULL,
TREE_VALUE (attributes), 0);
input_location = saved_loc;
return ret;
}
static unsigned int
ipa_target_clone (void)
{
struct cgraph_node *node;
auto_vec<cgraph_node *> to_dispatch;
FOR_EACH_FUNCTION (node)
if (expand_target_clones (node, node->definition))
to_dispatch.safe_push (node);
for (unsigned i = 0; i < to_dispatch.length (); i++)
create_dispatcher_calls (to_dispatch[i]);
return 0;
}
namespace {
const pass_data pass_data_target_clone =
{
SIMPLE_IPA_PASS, /* type */
"targetclone", /* name */
OPTGROUP_NONE, /* optinfo_flags */
TV_NONE, /* tv_id */
( PROP_ssa | PROP_cfg ), /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_update_ssa /* todo_flags_finish */
};
class pass_target_clone : public simple_ipa_opt_pass
{
public:
pass_target_clone (gcc::context *ctxt)
: simple_ipa_opt_pass (pass_data_target_clone, ctxt)
{}
/* opt_pass methods: */
virtual bool gate (function *);
virtual unsigned int execute (function *) { return ipa_target_clone (); }
};
bool
pass_target_clone::gate (function *)
{
return true;
}
} // anon namespace
simple_ipa_opt_pass *
make_pass_target_clone (gcc::context *ctxt)
{
return new pass_target_clone (ctxt);
}
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