Commonize handling of attr-fnspec
* attr-fnspec.h: New file. * calls.c (decl_return_flags): Use attr_fnspec. * gimple.c (gimple_call_arg_flags): Use attr_fnspec. (gimple_call_return_flags): Use attr_fnspec. * tree-into-ssa.c (pass_build_ssa::execute): Use attr_fnspec. * tree-ssa-alias.c (attr_fnspec::verify): New member fuction.
This commit is contained in:
Jan Hubicka
parent
b8e773e992
commit
05d39f0de9
5 changed files with 229 additions and 62 deletions
145
gcc/attr-fnspec.h
Normal file
145
gcc/attr-fnspec.h
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@ -0,0 +1,145 @@
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/* Handling of fnspec attribute specifiers
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Copyright (C) 2008-2020 Free Software Foundation, Inc.
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Contributed by Richard Guenther <rguenther@suse.de>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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/* Parse string of attribute "fn spec". This is an internal attribute
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describing side effects of a function as follows:
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character 0 specifies properties of return values as follows:
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'1'...'4' specifies number of argument function returns (as in memset)
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'm' specifies that returned value is noalias (as in malloc)
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'.' specifies that nothing is known.
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character 1+i specifies properties of argument number i as follows:
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'x' or 'X' specifies that parameter is unused.
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'r' or 'R' specifies that parameter is only read and memory pointed to is
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never dereferenced.
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'w' or 'W' specifies that parameter is only written to.
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'.' specifies that nothing is known.
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The uppercase letter in addition specifies that parameter
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is non-escaping. */
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#ifndef ATTR_FNSPEC_H
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#define ATTR_FNSPEC_H
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class attr_fnspec
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{
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private:
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/* fn spec attribute string. */
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const char *str;
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/* length of the fn spec string. */
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const unsigned len;
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/* Number of characters specifying return value. */
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const unsigned int return_desc_size = 1;
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/* Number of characters specifying size. */
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const unsigned int arg_desc_size = 1;
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/* Return start of specifier of arg i. */
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unsigned int arg_idx (int i)
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{
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return return_desc_size + arg_desc_size * i;
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}
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public:
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attr_fnspec (const char *str, unsigned len)
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: str (str), len (len)
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{
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if (flag_checking)
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verify ();
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}
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attr_fnspec (const_tree identifier)
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: str (TREE_STRING_POINTER (identifier)),
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len (TREE_STRING_LENGTH (identifier))
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{
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if (flag_checking)
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verify ();
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}
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/* Return true if arg I is specified. */
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bool
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arg_specified_p (unsigned int i)
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{
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return len >= arg_idx (i + 1);
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}
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/* True if the argument is not dereferenced recursively, thus only
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directly reachable memory is read or written. */
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bool
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arg_direct_p (unsigned int i)
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{
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unsigned int idx = arg_idx (i);
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gcc_checking_assert (arg_specified_p (i));
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return str[idx] == 'R' || str[idx] == 'W';
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}
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/* True if argument is used. */
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bool
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arg_used_p (unsigned int i)
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{
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unsigned int idx = arg_idx (i);
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gcc_checking_assert (arg_specified_p (i));
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return str[idx] != 'x' && str[idx] != 'X';
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}
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/* True if memory reached by the argument is readonly (not clobbered). */
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bool
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arg_readonly_p (unsigned int i)
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{
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unsigned int idx = arg_idx (i);
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gcc_checking_assert (arg_specified_p (i));
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return str[idx] == 'r' || str[idx] == 'R';
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}
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/* True if the argument does not escape. */
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bool
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arg_noescape_p (unsigned int i)
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{
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unsigned int idx = arg_idx (i);
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gcc_checking_assert (arg_specified_p (i));
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return str[idx] == 'w' || str[idx] == 'W'
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|| str[idx] == 'R' || str[idx] == 'r';
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}
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/* Return true if function returns value of its parameter. If ARG_NO is
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non-NULL return initialize it to the argument returned. */
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bool
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returns_arg (unsigned int *arg_no)
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{
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if (str[0] >= '1' && str[0] <= '4')
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{
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if (arg_no)
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*arg_no = str[0] - '1';
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return true;
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}
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return false;
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}
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/* Nonzero if the return value does not alias with anything. Functions
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with the malloc attribute have this set on their return value. */
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bool
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returns_noalias_p ()
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{
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return str[0] == 'm';
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}
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/* Check validity of the string. */
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void verify ();
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};
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#endif /* ATTR_FNSPEC_H */
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25
gcc/calls.c
25
gcc/calls.c
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@ -58,6 +58,7 @@ along with GCC; see the file COPYING3. If not see
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#include "attribs.h"
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#include "builtins.h"
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#include "gimple-fold.h"
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#include "attr-fnspec.h"
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#include "tree-pretty-print.h"
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@ -642,25 +643,15 @@ decl_return_flags (tree fndecl)
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if (!attr)
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return 0;
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attr = TREE_VALUE (TREE_VALUE (attr));
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if (!attr || TREE_STRING_LENGTH (attr) < 1)
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return 0;
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attr_fnspec fnspec (TREE_VALUE (TREE_VALUE (attr)));
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switch (TREE_STRING_POINTER (attr)[0])
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{
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case '1':
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case '2':
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case '3':
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case '4':
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return ERF_RETURNS_ARG | (TREE_STRING_POINTER (attr)[0] - '1');
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unsigned int arg;
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if (fnspec.returns_arg (&arg))
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return ERF_RETURNS_ARG | arg;
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case 'm':
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return ERF_NOALIAS;
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case '.':
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default:
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return 0;
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}
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if (fnspec.returns_noalias_p ())
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return ERF_NOALIAS;
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return 0;
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}
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/* Return nonzero when FNDECL represents a call to setjmp. */
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61
gcc/gimple.c
61
gcc/gimple.c
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@ -45,6 +45,7 @@ along with GCC; see the file COPYING3. If not see
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#include "attribs.h"
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#include "asan.h"
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#include "langhooks.h"
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#include "attr-fnspec.h"
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/* All the tuples have their operand vector (if present) at the very bottom
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@ -1512,31 +1513,26 @@ gimple_call_arg_flags (const gcall *stmt, unsigned arg)
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{
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const_tree attr = gimple_call_fnspec (stmt);
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if (!attr || 1 + arg >= (unsigned) TREE_STRING_LENGTH (attr))
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if (!attr)
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return 0;
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switch (TREE_STRING_POINTER (attr)[1 + arg])
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int flags = 0;
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attr_fnspec fnspec (attr);
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if (!fnspec.arg_specified_p (arg))
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;
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else if (!fnspec.arg_used_p (arg))
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flags = EAF_UNUSED;
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else
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{
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case 'x':
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case 'X':
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return EAF_UNUSED;
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case 'R':
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return EAF_DIRECT | EAF_NOCLOBBER | EAF_NOESCAPE;
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case 'r':
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return EAF_NOCLOBBER | EAF_NOESCAPE;
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case 'W':
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return EAF_DIRECT | EAF_NOESCAPE;
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case 'w':
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return EAF_NOESCAPE;
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case '.':
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default:
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return 0;
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if (fnspec.arg_direct_p (arg))
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flags |= EAF_DIRECT;
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if (fnspec.arg_noescape_p (arg))
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flags |= EAF_NOESCAPE;
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if (fnspec.arg_readonly_p (arg))
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flags |= EAF_NOCLOBBER;
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}
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return flags;
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}
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/* Detects return flags for the call STMT. */
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@ -1550,24 +1546,17 @@ gimple_call_return_flags (const gcall *stmt)
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return ERF_NOALIAS;
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attr = gimple_call_fnspec (stmt);
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if (!attr || TREE_STRING_LENGTH (attr) < 1)
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if (!attr)
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return 0;
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attr_fnspec fnspec (attr);
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switch (TREE_STRING_POINTER (attr)[0])
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{
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case '1':
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case '2':
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case '3':
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case '4':
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return ERF_RETURNS_ARG | (TREE_STRING_POINTER (attr)[0] - '1');
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unsigned int arg_no;
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if (fnspec.returns_arg (&arg_no))
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return ERF_RETURNS_ARG | arg_no;
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case 'm':
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return ERF_NOALIAS;
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case '.':
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default:
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return 0;
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}
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if (fnspec.returns_noalias_p ())
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return ERF_NOALIAS;
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return 0;
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}
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@ -41,6 +41,7 @@ along with GCC; see the file COPYING3. If not see
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#include "stringpool.h"
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#include "attribs.h"
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#include "asan.h"
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#include "attr-fnspec.h"
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#define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
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@ -2492,19 +2493,19 @@ pass_build_ssa::execute (function *fun)
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}
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/* Initialize SSA_NAME_POINTS_TO_READONLY_MEMORY. */
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tree fnspec = lookup_attribute ("fn spec",
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TYPE_ATTRIBUTES (TREE_TYPE (fun->decl)));
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if (fnspec)
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tree fnspec_tree
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= lookup_attribute ("fn spec",
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TYPE_ATTRIBUTES (TREE_TYPE (fun->decl)));
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if (fnspec_tree)
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{
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fnspec = TREE_VALUE (TREE_VALUE (fnspec));
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unsigned i = 1;
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attr_fnspec fnspec (TREE_VALUE (TREE_VALUE (fnspec_tree)));
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unsigned i = 0;
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for (tree arg = DECL_ARGUMENTS (cfun->decl);
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arg; arg = DECL_CHAIN (arg), ++i)
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{
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if (i >= (unsigned) TREE_STRING_LENGTH (fnspec))
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break;
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if (TREE_STRING_POINTER (fnspec)[i] == 'R'
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|| TREE_STRING_POINTER (fnspec)[i] == 'r')
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if (!fnspec.arg_specified_p (i))
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break;
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if (fnspec.arg_readonly_p (i))
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{
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tree name = ssa_default_def (fun, arg);
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if (name)
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@ -40,6 +40,8 @@ along with GCC; see the file COPYING3. If not see
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#include "varasm.h"
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#include "ipa-modref-tree.h"
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#include "ipa-modref.h"
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#include "attr-fnspec.h"
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#include "errors.h"
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/* Broad overview of how alias analysis on gimple works:
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@ -4012,3 +4014,42 @@ walk_aliased_vdefs (ao_ref *ref, tree vdef,
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return ret;
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}
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/* Verify validity of the fnspec string.
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See attr-fnspec.h for details. */
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void
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attr_fnspec::verify ()
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{
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/* FIXME: Fortran trans-decl.c contains multiple wrong fnspec strings.
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re-enable verification after these are fixed. */
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return;
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bool err = false;
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/* Check return value specifier. */
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if (len < return_desc_size)
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err = true;
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else if ((str[0] < '1' || str[0] > '4')
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&& str[0] != '.' && str[0] != 'm')
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err = true;
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/* Now check all parameters. */
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for (unsigned int i = 0; arg_specified_p (i); i++)
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{
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unsigned int idx = arg_idx (i);
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switch (str[idx])
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{
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case 'x':
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case 'X':
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case 'r':
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case 'R':
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case 'w':
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case 'W':
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case '.':
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break;
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default:
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err = true;
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}
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}
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if (err)
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internal_error ("invalid fn spec attribute %s", str);
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}
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