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Diffstat (limited to 'libmudflap/mf-heuristics.c')
| -rw-r--r-- | libmudflap/mf-heuristics.c | 169 |
1 files changed, 0 insertions, 169 deletions
diff --git a/libmudflap/mf-heuristics.c b/libmudflap/mf-heuristics.c deleted file mode 100644 index fa2dacb..0000000 --- a/libmudflap/mf-heuristics.c +++ /dev/null @@ -1,169 +0,0 @@ -/* Mudflap: narrow-pointer bounds-checking by tree rewriting. - Copyright (C) 2002-2013 Free Software Foundation, Inc. - Contributed by Frank Ch. Eigler <fche@redhat.com> - and Graydon Hoare <graydon@redhat.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. See the GNU General Public License -for more details. - -Under Section 7 of GPL version 3, you are granted additional -permissions described in the GCC Runtime Library Exception, version -3.1, as published by the Free Software Foundation. - -You should have received a copy of the GNU General Public License and -a copy of the GCC Runtime Library Exception along with this program; -see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -<http://www.gnu.org/licenses/>. */ - -#include "config.h" - -#include <stdio.h> - -#include "mf-runtime.h" -#include "mf-impl.h" - -#ifdef _MUDFLAP -#error "Do not compile this file with -fmudflap!" -#endif - - -extern char _end[]; -extern char ENTRY_POINT[]; - - -/* Run some quick validation of the given region. - Return -1 / 0 / 1 if the access known-invalid, possibly-valid, or known-valid. -*/ -int -__mf_heuristic_check (uintptr_t ptr, uintptr_t ptr_high) -{ - VERBOSE_TRACE ("mf: heuristic check\n"); - - /* XXX: Disable the stack bounding check for libmudflapth. We do - actually have enough information to track stack bounds (see - __mf_pthread_info in mf-hooks.c), so with a bit of future work, - this heuristic can be turned on. */ -#ifndef LIBMUDFLAPTH - - /* The first heuristic is to check stack bounds. This is a - transient condition and quick to check. */ - if (__mf_opts.heur_stack_bound) - { - uintptr_t stack_top_guess = (uintptr_t)__builtin_frame_address(0); -#if defined(__i386__) && defined (__linux__) - uintptr_t stack_segment_base = 0xC0000000; /* XXX: Bad assumption. */ -#else - /* Cause tests to fail. */ - uintptr_t stack_segment_base = 0; -#endif - - VERBOSE_TRACE ("mf: stack estimated as %p-%p\n", - (void *) stack_top_guess, (void *) stack_segment_base); - - if (ptr_high <= stack_segment_base && - ptr >= stack_top_guess && - ptr_high >= ptr) - { - return 1; - } - } -#endif - - - /* The second heuristic is to scan the range of memory regions - listed in /proc/self/maps, a special file provided by the Linux - kernel. Its results may be cached, and in fact, a GUESS object - may as well be recorded for interesting matching sections. */ - if (__mf_opts.heur_proc_map) - { - /* Keep a record of seen records from /proc/self/map. */ - enum { max_entries = 500 }; - struct proc_self_map_entry - { - uintptr_t low; - uintptr_t high; - }; - static struct proc_self_map_entry entry [max_entries]; - static unsigned entry_used [max_entries]; - - /* Look for a known proc_self_map entry that may cover this - region. If one exists, then this heuristic has already run, - and should not be run again. The check should be allowed to - fail. */ - unsigned i; - unsigned deja_vu = 0; - for (i=0; i<max_entries; i++) - { - if (entry_used[i] && - (entry[i].low <= ptr) && - (entry[i].high >= ptr_high)) - deja_vu = 1; - } - - if (! deja_vu) - { - /* Time to run the heuristic. Rescan /proc/self/maps; update the - entry[] array; XXX: remove expired entries, add new ones. - XXX: Consider entries that have grown (e.g., stack). */ - char buf[512]; - char flags[4]; - void *low, *high; - FILE *fp; - - fp = fopen ("/proc/self/maps", "r"); - if (fp) - { - while (fgets (buf, sizeof(buf), fp)) - { - if (sscanf (buf, "%p-%p %4c", &low, &high, flags) == 3) - { - if ((uintptr_t) low <= ptr && - (uintptr_t) high >= ptr_high) - { - for (i=0; i<max_entries; i++) - { - if (! entry_used[i]) - { - entry[i].low = (uintptr_t) low; - entry[i].high = (uintptr_t) high; - entry_used[i] = 1; - break; - } - } - - VERBOSE_TRACE ("mf: registering region #%d " - "%p-%p given %s", - i, (void *) low, (void *) high, buf); - - __mfu_register ((void *) low, (size_t) (high-low), - __MF_TYPE_GUESS, - "/proc/self/maps segment"); - - return 0; /* undecided (tending to cachable) */ - } - } - } - fclose (fp); - } - } - } - - - /* The third heuristic is to approve all accesses between _start (or its - equivalent for the given target) and _end, which should include all - text and initialized data. */ - if (__mf_opts.heur_start_end) - if (ptr >= (uintptr_t) & ENTRY_POINT && ptr_high <= (uintptr_t) & _end) - return 1; /* uncacheable */ - - return 0; /* unknown */ -} |