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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
1079 lines
27 KiB
C
1079 lines
27 KiB
C
/* Subroutines needed for unwinding stack frames for exception handling. */
|
||
/* Copyright (C) 1997-2021 Free Software Foundation, Inc.
|
||
|
||
This file is part of the GNU C Library.
|
||
|
||
The GNU C Library is free software; you can redistribute it and/or
|
||
modify it under the terms of the GNU Lesser General Public
|
||
License as published by the Free Software Foundation; either
|
||
version 2.1 of the License, or (at your option) any later version.
|
||
|
||
The GNU C Library 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
|
||
Lesser General Public License for more details.
|
||
|
||
You should have received a copy of the GNU Lesser General Public
|
||
License along with the GNU C Library; if not, see
|
||
<https://www.gnu.org/licenses/>. */
|
||
|
||
#ifdef _LIBC
|
||
# include <shlib-compat.h>
|
||
#endif
|
||
|
||
#if !defined _LIBC || SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2_5)
|
||
|
||
#ifdef _LIBC
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||
#include <stdlib.h>
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||
#include <string.h>
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||
#include <libc-lock.h>
|
||
#include <dwarf2.h>
|
||
#include <unwind.h>
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||
#define NO_BASE_OF_ENCODED_VALUE
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||
#include <unwind-pe.h>
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||
#include <unwind-dw2-fde.h>
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||
#else
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||
#ifndef _Unwind_Find_FDE
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||
#include "tconfig.h"
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||
#include "tsystem.h"
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||
#include "dwarf2.h"
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||
#include "unwind.h"
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||
#define NO_BASE_OF_ENCODED_VALUE
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||
#include "unwind-pe.h"
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||
#include "unwind-dw2-fde.h"
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||
#include "gthr.h"
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||
#endif
|
||
#endif
|
||
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||
/* The unseen_objects list contains objects that have been registered
|
||
but not yet categorized in any way. The seen_objects list has had
|
||
it's pc_begin and count fields initialized at minimum, and is sorted
|
||
by decreasing value of pc_begin. */
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||
static struct object *unseen_objects;
|
||
static struct object *seen_objects;
|
||
|
||
#ifdef _LIBC
|
||
|
||
__libc_lock_define_initialized (static, object_mutex)
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||
#define init_object_mutex_once()
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||
#define __gthread_mutex_lock(m) __libc_lock_lock (*(m))
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||
#define __gthread_mutex_unlock(m) __libc_lock_unlock (*(m))
|
||
|
||
void __register_frame_info_bases (void *begin, struct object *ob,
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||
void *tbase, void *dbase);
|
||
hidden_proto (__register_frame_info_bases)
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||
void __register_frame_info_table_bases (void *begin,
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||
struct object *ob,
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||
void *tbase, void *dbase);
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||
hidden_proto (__register_frame_info_table_bases)
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||
void *__deregister_frame_info_bases (void *begin);
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||
hidden_proto (__deregister_frame_info_bases)
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||
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||
#else
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||
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||
#ifdef __GTHREAD_MUTEX_INIT
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static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
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#else
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static __gthread_mutex_t object_mutex;
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#endif
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#ifdef __GTHREAD_MUTEX_INIT_FUNCTION
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static void
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init_object_mutex (void)
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{
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__GTHREAD_MUTEX_INIT_FUNCTION (&object_mutex);
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}
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||
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static void
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||
init_object_mutex_once (void)
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{
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static __gthread_once_t once = __GTHREAD_ONCE_INIT;
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__gthread_once (&once, init_object_mutex);
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||
}
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#else
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#define init_object_mutex_once()
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#endif
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||
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||
#endif /* _LIBC */
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||
|
||
/* Called from crtbegin.o to register the unwind info for an object. */
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||
|
||
void
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||
__register_frame_info_bases (void *begin, struct object *ob,
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||
void *tbase, void *dbase)
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||
{
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||
/* If .eh_frame is empty, don't register at all. */
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||
if (*(uword *) begin == 0)
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||
return;
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||
|
||
ob->pc_begin = (void *)-1;
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||
ob->tbase = tbase;
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||
ob->dbase = dbase;
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||
ob->u.single = begin;
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||
ob->s.i = 0;
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ob->s.b.encoding = DW_EH_PE_omit;
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||
#ifdef DWARF2_OBJECT_END_PTR_EXTENSION
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ob->fde_end = NULL;
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||
#endif
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||
init_object_mutex_once ();
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__gthread_mutex_lock (&object_mutex);
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||
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||
ob->next = unseen_objects;
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||
unseen_objects = ob;
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||
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||
__gthread_mutex_unlock (&object_mutex);
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||
}
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||
hidden_def (__register_frame_info_bases)
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void
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||
__register_frame_info (void *begin, struct object *ob)
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||
{
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__register_frame_info_bases (begin, ob, 0, 0);
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||
}
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||
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||
void
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||
__register_frame (void *begin)
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||
{
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||
struct object *ob;
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||
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||
/* If .eh_frame is empty, don't register at all. */
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||
if (*(uword *) begin == 0)
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||
return;
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||
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||
ob = (struct object *) malloc (sizeof (struct object));
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__register_frame_info_bases (begin, ob, 0, 0);
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||
}
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||
/* Similar, but BEGIN is actually a pointer to a table of unwind entries
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for different translation units. Called from the file generated by
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collect2. */
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||
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||
void
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||
__register_frame_info_table_bases (void *begin, struct object *ob,
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void *tbase, void *dbase)
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||
{
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ob->pc_begin = (void *)-1;
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||
ob->tbase = tbase;
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||
ob->dbase = dbase;
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ob->u.array = begin;
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||
ob->s.i = 0;
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||
ob->s.b.from_array = 1;
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||
ob->s.b.encoding = DW_EH_PE_omit;
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init_object_mutex_once ();
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__gthread_mutex_lock (&object_mutex);
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ob->next = unseen_objects;
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unseen_objects = ob;
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__gthread_mutex_unlock (&object_mutex);
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}
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hidden_def (__register_frame_info_table_bases)
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||
void
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__register_frame_info_table (void *begin, struct object *ob)
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||
{
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__register_frame_info_table_bases (begin, ob, 0, 0);
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}
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void
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__register_frame_table (void *begin)
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{
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struct object *ob = (struct object *) malloc (sizeof (struct object));
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__register_frame_info_table_bases (begin, ob, 0, 0);
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}
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/* Called from crtbegin.o to deregister the unwind info for an object. */
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/* ??? Glibc has for a while now exported __register_frame_info and
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__deregister_frame_info. If we call __register_frame_info_bases
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from crtbegin (wherein it is declared weak), and this object does
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not get pulled from libgcc.a for other reasons, then the
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invocation of __deregister_frame_info will be resolved from glibc.
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Since the registration did not happen there, we'll abort.
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||
Therefore, declare a new deregistration entry point that does the
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exact same thing, but will resolve to the same library as
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implements __register_frame_info_bases. */
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void *
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__deregister_frame_info_bases (void *begin)
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{
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struct object **p;
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struct object *ob = 0;
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struct fde_vector *tofree = NULL;
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/* If .eh_frame is empty, we haven't registered. */
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if (*(uword *) begin == 0)
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return ob;
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init_object_mutex_once ();
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__gthread_mutex_lock (&object_mutex);
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for (p = &unseen_objects; *p ; p = &(*p)->next)
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if ((*p)->u.single == begin)
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{
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ob = *p;
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*p = ob->next;
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goto out;
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}
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for (p = &seen_objects; *p ; p = &(*p)->next)
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if ((*p)->s.b.sorted)
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{
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if ((*p)->u.sort->orig_data == begin)
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{
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ob = *p;
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*p = ob->next;
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tofree = ob->u.sort;
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goto out;
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}
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}
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else
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{
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if ((*p)->u.single == begin)
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{
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ob = *p;
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*p = ob->next;
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goto out;
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}
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}
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__gthread_mutex_unlock (&object_mutex);
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abort ();
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out:
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__gthread_mutex_unlock (&object_mutex);
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free (tofree);
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return (void *) ob;
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}
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hidden_def (__deregister_frame_info_bases)
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void *
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__deregister_frame_info (void *begin)
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{
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return __deregister_frame_info_bases (begin);
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}
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void
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__deregister_frame (void *begin)
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{
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/* If .eh_frame is empty, we haven't registered. */
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if (*(uword *) begin != 0)
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free (__deregister_frame_info_bases (begin));
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}
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/* Like base_of_encoded_value, but take the base from a struct object
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instead of an _Unwind_Context. */
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static _Unwind_Ptr
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base_from_object (unsigned char encoding, struct object *ob)
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{
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if (encoding == DW_EH_PE_omit)
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return 0;
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||
switch (encoding & 0x70)
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{
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case DW_EH_PE_absptr:
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case DW_EH_PE_pcrel:
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case DW_EH_PE_aligned:
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return 0;
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case DW_EH_PE_textrel:
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return (_Unwind_Ptr) ob->tbase;
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case DW_EH_PE_datarel:
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return (_Unwind_Ptr) ob->dbase;
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}
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abort ();
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}
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||
/* Return the FDE pointer encoding from the CIE. */
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/* ??? This is a subset of extract_cie_info from unwind-dw2.c. */
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static int
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get_cie_encoding (struct dwarf_cie *cie)
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||
{
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const unsigned char *aug, *p;
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_Unwind_Ptr dummy;
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_Unwind_Word utmp;
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_Unwind_Sword stmp;
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aug = cie->augmentation;
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if (aug[0] != 'z')
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return DW_EH_PE_absptr;
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||
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||
/* Skip the augmentation string. */
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p = aug + strlen ((const char *) aug) + 1;
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p = read_uleb128 (p, &utmp); /* Skip code alignment. */
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p = read_sleb128 (p, &stmp); /* Skip data alignment. */
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p++; /* Skip return address column. */
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aug++; /* Skip 'z' */
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p = read_uleb128 (p, &utmp); /* Skip augmentation length. */
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while (1)
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{
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||
/* This is what we're looking for. */
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if (*aug == 'R')
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return *p;
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||
/* Personality encoding and pointer. */
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||
else if (*aug == 'P')
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{
|
||
/* ??? Avoid dereferencing indirect pointers, since we're
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faking the base address. Gotta keep DW_EH_PE_aligned
|
||
intact, however. */
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p = read_encoded_value_with_base (*p & 0x7F, 0, p + 1, &dummy);
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||
}
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||
/* LSDA encoding. */
|
||
else if (*aug == 'L')
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p++;
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||
/* Otherwise end of string, or unknown augmentation. */
|
||
else
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||
return DW_EH_PE_absptr;
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aug++;
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||
}
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||
}
|
||
|
||
static inline int
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||
get_fde_encoding (struct dwarf_fde *f)
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{
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return get_cie_encoding (get_cie (f));
|
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}
|
||
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||
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||
/* Sorting an array of FDEs by address.
|
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(Ideally we would have the linker sort the FDEs so we don't have to do
|
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it at run time. But the linkers are not yet prepared for this.) */
|
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|
||
/* Return the Nth pc_begin value from FDE x. */
|
||
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static inline _Unwind_Ptr
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get_pc_begin (fde *x, size_t n)
|
||
{
|
||
_Unwind_Ptr p;
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||
memcpy (&p, x->pc_begin + n * sizeof (_Unwind_Ptr), sizeof (_Unwind_Ptr));
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return p;
|
||
}
|
||
|
||
/* Comparison routines. Three variants of increasing complexity. */
|
||
|
||
static int
|
||
fde_unencoded_compare (struct object *ob __attribute__((unused)),
|
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fde *x, fde *y)
|
||
{
|
||
_Unwind_Ptr x_ptr = get_pc_begin (x, 0);
|
||
_Unwind_Ptr y_ptr = get_pc_begin (y, 0);
|
||
|
||
if (x_ptr > y_ptr)
|
||
return 1;
|
||
if (x_ptr < y_ptr)
|
||
return -1;
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
fde_single_encoding_compare (struct object *ob, fde *x, fde *y)
|
||
{
|
||
_Unwind_Ptr base, x_ptr, y_ptr;
|
||
|
||
base = base_from_object (ob->s.b.encoding, ob);
|
||
read_encoded_value_with_base (ob->s.b.encoding, base, x->pc_begin, &x_ptr);
|
||
read_encoded_value_with_base (ob->s.b.encoding, base, y->pc_begin, &y_ptr);
|
||
|
||
if (x_ptr > y_ptr)
|
||
return 1;
|
||
if (x_ptr < y_ptr)
|
||
return -1;
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
fde_mixed_encoding_compare (struct object *ob, fde *x, fde *y)
|
||
{
|
||
int x_encoding, y_encoding;
|
||
_Unwind_Ptr x_ptr, y_ptr;
|
||
|
||
x_encoding = get_fde_encoding (x);
|
||
read_encoded_value_with_base (x_encoding, base_from_object (x_encoding, ob),
|
||
x->pc_begin, &x_ptr);
|
||
|
||
y_encoding = get_fde_encoding (y);
|
||
read_encoded_value_with_base (y_encoding, base_from_object (y_encoding, ob),
|
||
y->pc_begin, &y_ptr);
|
||
|
||
if (x_ptr > y_ptr)
|
||
return 1;
|
||
if (x_ptr < y_ptr)
|
||
return -1;
|
||
return 0;
|
||
}
|
||
|
||
typedef int (*fde_compare_t) (struct object *, fde *, fde *);
|
||
|
||
|
||
/* This is a special mix of insertion sort and heap sort, optimized for
|
||
the data sets that actually occur. They look like
|
||
101 102 103 127 128 105 108 110 190 111 115 119 125 160 126 129 130.
|
||
I.e. a linearly increasing sequence (coming from functions in the text
|
||
section), with additionally a few unordered elements (coming from functions
|
||
in gnu_linkonce sections) whose values are higher than the values in the
|
||
surrounding linear sequence (but not necessarily higher than the values
|
||
at the end of the linear sequence!).
|
||
The worst-case total run time is O(N) + O(n log (n)), where N is the
|
||
total number of FDEs and n is the number of erratic ones. */
|
||
|
||
struct fde_accumulator
|
||
{
|
||
struct fde_vector *linear;
|
||
struct fde_vector *erratic;
|
||
};
|
||
|
||
static int
|
||
start_fde_sort (struct fde_accumulator *accu, size_t count)
|
||
{
|
||
size_t size;
|
||
if (! count)
|
||
return 0;
|
||
|
||
size = sizeof (struct fde_vector) + sizeof (fde *) * count;
|
||
if ((accu->linear = (struct fde_vector *) malloc (size)))
|
||
{
|
||
accu->linear->count = 0;
|
||
if ((accu->erratic = (struct fde_vector *) malloc (size)))
|
||
accu->erratic->count = 0;
|
||
return 1;
|
||
}
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
static inline void
|
||
fde_insert (struct fde_accumulator *accu, fde *this_fde)
|
||
{
|
||
if (accu->linear)
|
||
accu->linear->array[accu->linear->count++] = this_fde;
|
||
}
|
||
|
||
/* Split LINEAR into a linear sequence with low values and an erratic
|
||
sequence with high values, put the linear one (of longest possible
|
||
length) into LINEAR and the erratic one into ERRATIC. This is O(N).
|
||
|
||
Because the longest linear sequence we are trying to locate within the
|
||
incoming LINEAR array can be interspersed with (high valued) erratic
|
||
entries. We construct a chain indicating the sequenced entries.
|
||
To avoid having to allocate this chain, we overlay it onto the space of
|
||
the ERRATIC array during construction. A final pass iterates over the
|
||
chain to determine what should be placed in the ERRATIC array, and
|
||
what is the linear sequence. This overlay is safe from aliasing. */
|
||
|
||
static void
|
||
fde_split (struct object *ob, fde_compare_t fde_compare,
|
||
struct fde_vector *linear, struct fde_vector *erratic)
|
||
{
|
||
static fde *marker;
|
||
size_t count = linear->count;
|
||
fde **chain_end = ▮
|
||
size_t i, j, k;
|
||
|
||
/* This should optimize out, but it is wise to make sure this assumption
|
||
is correct. Should these have different sizes, we cannot cast between
|
||
them and the overlaying onto ERRATIC will not work. */
|
||
if (sizeof (fde *) != sizeof (fde **))
|
||
abort ();
|
||
|
||
for (i = 0; i < count; i++)
|
||
{
|
||
fde **probe;
|
||
|
||
for (probe = chain_end;
|
||
probe != &marker && fde_compare (ob, linear->array[i], *probe) < 0;
|
||
probe = chain_end)
|
||
{
|
||
chain_end = (fde **) erratic->array[probe - linear->array];
|
||
erratic->array[probe - linear->array] = NULL;
|
||
}
|
||
erratic->array[i] = (fde *) chain_end;
|
||
chain_end = &linear->array[i];
|
||
}
|
||
|
||
/* Each entry in LINEAR which is part of the linear sequence we have
|
||
discovered will correspond to a non-NULL entry in the chain we built in
|
||
the ERRATIC array. */
|
||
for (i = j = k = 0; i < count; i++)
|
||
if (erratic->array[i])
|
||
linear->array[j++] = linear->array[i];
|
||
else
|
||
erratic->array[k++] = linear->array[i];
|
||
linear->count = j;
|
||
erratic->count = k;
|
||
}
|
||
|
||
/* This is O(n log(n)). BSD/OS defines heapsort in stdlib.h, so we must
|
||
use a name that does not conflict. */
|
||
|
||
static void
|
||
frame_heapsort (struct object *ob, fde_compare_t fde_compare,
|
||
struct fde_vector *erratic)
|
||
{
|
||
/* For a description of this algorithm, see:
|
||
Samuel P. Harbison, Guy L. Steele Jr.: C, a reference manual, 2nd ed.,
|
||
p. 60-61. */
|
||
fde ** a = erratic->array;
|
||
/* A portion of the array is called a "heap" if for all i>=0:
|
||
If i and 2i+1 are valid indices, then a[i] >= a[2i+1].
|
||
If i and 2i+2 are valid indices, then a[i] >= a[2i+2]. */
|
||
#define SWAP(x,y) do { fde * tmp = x; x = y; y = tmp; } while (0)
|
||
size_t n = erratic->count;
|
||
size_t m = n;
|
||
size_t i;
|
||
|
||
while (m > 0)
|
||
{
|
||
/* Invariant: a[m..n-1] is a heap. */
|
||
m--;
|
||
for (i = m; 2*i+1 < n; )
|
||
{
|
||
if (2*i+2 < n
|
||
&& fde_compare (ob, a[2*i+2], a[2*i+1]) > 0
|
||
&& fde_compare (ob, a[2*i+2], a[i]) > 0)
|
||
{
|
||
SWAP (a[i], a[2*i+2]);
|
||
i = 2*i+2;
|
||
}
|
||
else if (fde_compare (ob, a[2*i+1], a[i]) > 0)
|
||
{
|
||
SWAP (a[i], a[2*i+1]);
|
||
i = 2*i+1;
|
||
}
|
||
else
|
||
break;
|
||
}
|
||
}
|
||
while (n > 1)
|
||
{
|
||
/* Invariant: a[0..n-1] is a heap. */
|
||
n--;
|
||
SWAP (a[0], a[n]);
|
||
for (i = 0; 2*i+1 < n; )
|
||
{
|
||
if (2*i+2 < n
|
||
&& fde_compare (ob, a[2*i+2], a[2*i+1]) > 0
|
||
&& fde_compare (ob, a[2*i+2], a[i]) > 0)
|
||
{
|
||
SWAP (a[i], a[2*i+2]);
|
||
i = 2*i+2;
|
||
}
|
||
else if (fde_compare (ob, a[2*i+1], a[i]) > 0)
|
||
{
|
||
SWAP (a[i], a[2*i+1]);
|
||
i = 2*i+1;
|
||
}
|
||
else
|
||
break;
|
||
}
|
||
}
|
||
#undef SWAP
|
||
}
|
||
|
||
/* Merge V1 and V2, both sorted, and put the result into V1. */
|
||
static void
|
||
fde_merge (struct object *ob, fde_compare_t fde_compare,
|
||
struct fde_vector *v1, struct fde_vector *v2)
|
||
{
|
||
size_t i1, i2;
|
||
fde * fde2;
|
||
|
||
i2 = v2->count;
|
||
if (i2 > 0)
|
||
{
|
||
i1 = v1->count;
|
||
do
|
||
{
|
||
i2--;
|
||
fde2 = v2->array[i2];
|
||
while (i1 > 0 && fde_compare (ob, v1->array[i1-1], fde2) > 0)
|
||
{
|
||
v1->array[i1+i2] = v1->array[i1-1];
|
||
i1--;
|
||
}
|
||
v1->array[i1+i2] = fde2;
|
||
}
|
||
while (i2 > 0);
|
||
v1->count += v2->count;
|
||
}
|
||
}
|
||
|
||
static void
|
||
end_fde_sort (struct object *ob, struct fde_accumulator *accu, size_t count)
|
||
{
|
||
fde_compare_t fde_compare;
|
||
|
||
if (accu->linear->count != count)
|
||
abort ();
|
||
|
||
if (ob->s.b.mixed_encoding)
|
||
fde_compare = fde_mixed_encoding_compare;
|
||
else if (ob->s.b.encoding == DW_EH_PE_absptr)
|
||
fde_compare = fde_unencoded_compare;
|
||
else
|
||
fde_compare = fde_single_encoding_compare;
|
||
|
||
if (accu->erratic)
|
||
{
|
||
fde_split (ob, fde_compare, accu->linear, accu->erratic);
|
||
if (accu->linear->count + accu->erratic->count != count)
|
||
abort ();
|
||
frame_heapsort (ob, fde_compare, accu->erratic);
|
||
fde_merge (ob, fde_compare, accu->linear, accu->erratic);
|
||
free (accu->erratic);
|
||
}
|
||
else
|
||
{
|
||
/* We've not managed to malloc an erratic array,
|
||
so heap sort in the linear one. */
|
||
frame_heapsort (ob, fde_compare, accu->linear);
|
||
}
|
||
}
|
||
|
||
|
||
/* Update encoding, mixed_encoding, and pc_begin for OB for the
|
||
fde array beginning at THIS_FDE. Return the number of fdes
|
||
encountered along the way. */
|
||
|
||
static size_t
|
||
classify_object_over_fdes (struct object *ob, fde *this_fde)
|
||
{
|
||
struct dwarf_cie *last_cie = 0;
|
||
size_t count = 0;
|
||
int encoding = DW_EH_PE_absptr;
|
||
_Unwind_Ptr base = 0;
|
||
|
||
for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
||
{
|
||
struct dwarf_cie *this_cie;
|
||
_Unwind_Ptr mask, pc_begin;
|
||
|
||
/* Skip CIEs. */
|
||
if (this_fde->CIE_delta == 0)
|
||
continue;
|
||
|
||
/* Determine the encoding for this FDE. Note mixed encoded
|
||
objects for later. */
|
||
this_cie = get_cie (this_fde);
|
||
if (this_cie != last_cie)
|
||
{
|
||
last_cie = this_cie;
|
||
encoding = get_cie_encoding (this_cie);
|
||
base = base_from_object (encoding, ob);
|
||
if (ob->s.b.encoding == DW_EH_PE_omit)
|
||
ob->s.b.encoding = encoding;
|
||
else if (ob->s.b.encoding != encoding)
|
||
ob->s.b.mixed_encoding = 1;
|
||
}
|
||
|
||
read_encoded_value_with_base (encoding, base, this_fde->pc_begin,
|
||
&pc_begin);
|
||
|
||
/* Take care to ignore link-once functions that were removed.
|
||
In these cases, the function address will be NULL, but if
|
||
the encoding is smaller than a pointer a true NULL may not
|
||
be representable. Assume 0 in the representable bits is NULL. */
|
||
mask = size_of_encoded_value (encoding);
|
||
if (mask < sizeof (void *))
|
||
mask = (1L << (mask << 3)) - 1;
|
||
else
|
||
mask = -1;
|
||
|
||
if ((pc_begin & mask) == 0)
|
||
continue;
|
||
|
||
count += 1;
|
||
if ((void *) pc_begin < ob->pc_begin)
|
||
ob->pc_begin = (void *) pc_begin;
|
||
}
|
||
|
||
return count;
|
||
}
|
||
|
||
static void
|
||
add_fdes (struct object *ob, struct fde_accumulator *accu, fde *this_fde)
|
||
{
|
||
struct dwarf_cie *last_cie = 0;
|
||
int encoding = ob->s.b.encoding;
|
||
_Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob);
|
||
|
||
for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
||
{
|
||
struct dwarf_cie *this_cie;
|
||
|
||
/* Skip CIEs. */
|
||
if (this_fde->CIE_delta == 0)
|
||
continue;
|
||
|
||
if (ob->s.b.mixed_encoding)
|
||
{
|
||
/* Determine the encoding for this FDE. Note mixed encoded
|
||
objects for later. */
|
||
this_cie = get_cie (this_fde);
|
||
if (this_cie != last_cie)
|
||
{
|
||
last_cie = this_cie;
|
||
encoding = get_cie_encoding (this_cie);
|
||
base = base_from_object (encoding, ob);
|
||
}
|
||
}
|
||
|
||
if (encoding == DW_EH_PE_absptr)
|
||
{
|
||
if (get_pc_begin (this_fde, 0) == 0)
|
||
continue;
|
||
}
|
||
else
|
||
{
|
||
_Unwind_Ptr pc_begin, mask;
|
||
|
||
read_encoded_value_with_base (encoding, base, this_fde->pc_begin,
|
||
&pc_begin);
|
||
|
||
/* Take care to ignore link-once functions that were removed.
|
||
In these cases, the function address will be NULL, but if
|
||
the encoding is smaller than a pointer a true NULL may not
|
||
be representable. Assume 0 in the representable bits is NULL. */
|
||
mask = size_of_encoded_value (encoding);
|
||
if (mask < sizeof (void *))
|
||
mask = (1L << (mask << 3)) - 1;
|
||
else
|
||
mask = -1;
|
||
|
||
if ((pc_begin & mask) == 0)
|
||
continue;
|
||
}
|
||
|
||
fde_insert (accu, this_fde);
|
||
}
|
||
}
|
||
|
||
/* Set up a sorted array of pointers to FDEs for a loaded object. We
|
||
count up the entries before allocating the array because it's likely to
|
||
be faster. We can be called multiple times, should we have failed to
|
||
allocate a sorted fde array on a previous occasion. */
|
||
|
||
static void
|
||
init_object (struct object* ob)
|
||
{
|
||
struct fde_accumulator accu;
|
||
size_t count;
|
||
|
||
count = ob->s.b.count;
|
||
if (count == 0)
|
||
{
|
||
if (ob->s.b.from_array)
|
||
{
|
||
fde **p = ob->u.array;
|
||
for (count = 0; *p; ++p)
|
||
count += classify_object_over_fdes (ob, *p);
|
||
}
|
||
else
|
||
count = classify_object_over_fdes (ob, ob->u.single);
|
||
|
||
/* The count field we have in the main struct object is somewhat
|
||
limited, but should suffice for virtually all cases. If the
|
||
counted value doesn't fit, re-write a zero. The worst that
|
||
happens is that we re-count next time -- admittedly non-trivial
|
||
in that this implies some 2M fdes, but at least we function. */
|
||
ob->s.b.count = count;
|
||
if (ob->s.b.count != count)
|
||
ob->s.b.count = 0;
|
||
}
|
||
|
||
if (!start_fde_sort (&accu, count))
|
||
return;
|
||
|
||
if (ob->s.b.from_array)
|
||
{
|
||
fde **p;
|
||
for (p = ob->u.array; *p; ++p)
|
||
add_fdes (ob, &accu, *p);
|
||
}
|
||
else
|
||
add_fdes (ob, &accu, ob->u.single);
|
||
|
||
end_fde_sort (ob, &accu, count);
|
||
|
||
/* Save the original fde pointer, since this is the key by which the
|
||
DSO will deregister the object. */
|
||
accu.linear->orig_data = ob->u.single;
|
||
ob->u.sort = accu.linear;
|
||
|
||
ob->s.b.sorted = 1;
|
||
}
|
||
|
||
/* A linear search through a set of FDEs for the given PC. This is
|
||
used when there was insufficient memory to allocate and sort an
|
||
array. */
|
||
|
||
static fde *
|
||
linear_search_fdes (struct object *ob, fde *this_fde, void *pc)
|
||
{
|
||
struct dwarf_cie *last_cie = 0;
|
||
int encoding = ob->s.b.encoding;
|
||
_Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob);
|
||
|
||
for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
||
{
|
||
struct dwarf_cie *this_cie;
|
||
_Unwind_Ptr pc_begin, pc_range;
|
||
|
||
/* Skip CIEs. */
|
||
if (this_fde->CIE_delta == 0)
|
||
continue;
|
||
|
||
if (ob->s.b.mixed_encoding)
|
||
{
|
||
/* Determine the encoding for this FDE. Note mixed encoded
|
||
objects for later. */
|
||
this_cie = get_cie (this_fde);
|
||
if (this_cie != last_cie)
|
||
{
|
||
last_cie = this_cie;
|
||
encoding = get_cie_encoding (this_cie);
|
||
base = base_from_object (encoding, ob);
|
||
}
|
||
}
|
||
|
||
if (encoding == DW_EH_PE_absptr)
|
||
{
|
||
pc_begin = get_pc_begin (this_fde, 0);
|
||
pc_range = get_pc_begin (this_fde, 1);
|
||
if (pc_begin == 0)
|
||
continue;
|
||
}
|
||
else
|
||
{
|
||
_Unwind_Ptr mask;
|
||
const unsigned char *p;
|
||
|
||
p = read_encoded_value_with_base (encoding, base,
|
||
this_fde->pc_begin, &pc_begin);
|
||
read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
||
|
||
/* Take care to ignore link-once functions that were removed.
|
||
In these cases, the function address will be NULL, but if
|
||
the encoding is smaller than a pointer a true NULL may not
|
||
be representable. Assume 0 in the representable bits is NULL. */
|
||
mask = size_of_encoded_value (encoding);
|
||
if (mask < sizeof (void *))
|
||
mask = (1L << (mask << 3)) - 1;
|
||
else
|
||
mask = -1;
|
||
|
||
if ((pc_begin & mask) == 0)
|
||
continue;
|
||
}
|
||
|
||
if ((_Unwind_Ptr) pc - pc_begin < pc_range)
|
||
return this_fde;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* Binary search for an FDE containing the given PC. Here are three
|
||
implementations of increasing complexity. */
|
||
|
||
static fde *
|
||
binary_search_unencoded_fdes (struct object *ob, void *pc)
|
||
{
|
||
struct fde_vector *vec = ob->u.sort;
|
||
size_t lo, hi;
|
||
|
||
for (lo = 0, hi = vec->count; lo < hi; )
|
||
{
|
||
size_t i = (lo + hi) / 2;
|
||
fde *f = vec->array[i];
|
||
void *pc_begin;
|
||
uaddr pc_range;
|
||
|
||
pc_begin = (void *) get_pc_begin (f, 0);
|
||
pc_range = (uaddr) get_pc_begin (f, 1);
|
||
|
||
if (pc < pc_begin)
|
||
hi = i;
|
||
else if (pc >= pc_begin + pc_range)
|
||
lo = i + 1;
|
||
else
|
||
return f;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static fde *
|
||
binary_search_single_encoding_fdes (struct object *ob, void *pc)
|
||
{
|
||
struct fde_vector *vec = ob->u.sort;
|
||
int encoding = ob->s.b.encoding;
|
||
_Unwind_Ptr base = base_from_object (encoding, ob);
|
||
size_t lo, hi;
|
||
|
||
for (lo = 0, hi = vec->count; lo < hi; )
|
||
{
|
||
size_t i = (lo + hi) / 2;
|
||
fde *f = vec->array[i];
|
||
_Unwind_Ptr pc_begin, pc_range;
|
||
const unsigned char *p;
|
||
|
||
p = read_encoded_value_with_base (encoding, base, f->pc_begin,
|
||
&pc_begin);
|
||
read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
||
|
||
if ((_Unwind_Ptr) pc < pc_begin)
|
||
hi = i;
|
||
else if ((_Unwind_Ptr) pc >= pc_begin + pc_range)
|
||
lo = i + 1;
|
||
else
|
||
return f;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static fde *
|
||
binary_search_mixed_encoding_fdes (struct object *ob, void *pc)
|
||
{
|
||
struct fde_vector *vec = ob->u.sort;
|
||
size_t lo, hi;
|
||
|
||
for (lo = 0, hi = vec->count; lo < hi; )
|
||
{
|
||
size_t i = (lo + hi) / 2;
|
||
fde *f = vec->array[i];
|
||
_Unwind_Ptr pc_begin, pc_range;
|
||
const unsigned char *p;
|
||
int encoding;
|
||
|
||
encoding = get_fde_encoding (f);
|
||
p = read_encoded_value_with_base (encoding,
|
||
base_from_object (encoding, ob),
|
||
f->pc_begin, &pc_begin);
|
||
read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
||
|
||
if ((_Unwind_Ptr) pc < pc_begin)
|
||
hi = i;
|
||
else if ((_Unwind_Ptr) pc >= pc_begin + pc_range)
|
||
lo = i + 1;
|
||
else
|
||
return f;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static fde *
|
||
search_object (struct object* ob, void *pc)
|
||
{
|
||
/* If the data hasn't been sorted, try to do this now. We may have
|
||
more memory available than last time we tried. */
|
||
if (! ob->s.b.sorted)
|
||
{
|
||
init_object (ob);
|
||
|
||
/* Despite the above comment, the normal reason to get here is
|
||
that we've not processed this object before. A quick range
|
||
check is in order. */
|
||
if (pc < ob->pc_begin)
|
||
return NULL;
|
||
}
|
||
|
||
if (ob->s.b.sorted)
|
||
{
|
||
if (ob->s.b.mixed_encoding)
|
||
return binary_search_mixed_encoding_fdes (ob, pc);
|
||
else if (ob->s.b.encoding == DW_EH_PE_absptr)
|
||
return binary_search_unencoded_fdes (ob, pc);
|
||
else
|
||
return binary_search_single_encoding_fdes (ob, pc);
|
||
}
|
||
else
|
||
{
|
||
/* Long slow labourious linear search, cos we've no memory. */
|
||
if (ob->s.b.from_array)
|
||
{
|
||
fde **p;
|
||
for (p = ob->u.array; *p ; p++)
|
||
{
|
||
fde *f = linear_search_fdes (ob, *p, pc);
|
||
if (f)
|
||
return f;
|
||
}
|
||
return NULL;
|
||
}
|
||
else
|
||
return linear_search_fdes (ob, ob->u.single, pc);
|
||
}
|
||
}
|
||
|
||
fde *
|
||
_Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
|
||
{
|
||
struct object *ob;
|
||
fde *f = NULL;
|
||
|
||
init_object_mutex_once ();
|
||
__gthread_mutex_lock (&object_mutex);
|
||
|
||
/* Linear search through the classified objects, to find the one
|
||
containing the pc. Note that pc_begin is sorted descending, and
|
||
we expect objects to be non-overlapping. */
|
||
for (ob = seen_objects; ob; ob = ob->next)
|
||
if (pc >= ob->pc_begin)
|
||
{
|
||
f = search_object (ob, pc);
|
||
if (f)
|
||
goto fini;
|
||
break;
|
||
}
|
||
|
||
/* Classify and search the objects we've not yet processed. */
|
||
while ((ob = unseen_objects))
|
||
{
|
||
struct object **p;
|
||
|
||
unseen_objects = ob->next;
|
||
f = search_object (ob, pc);
|
||
|
||
/* Insert the object into the classified list. */
|
||
for (p = &seen_objects; *p ; p = &(*p)->next)
|
||
if ((*p)->pc_begin < ob->pc_begin)
|
||
break;
|
||
ob->next = *p;
|
||
*p = ob;
|
||
|
||
if (f)
|
||
goto fini;
|
||
}
|
||
|
||
fini:
|
||
__gthread_mutex_unlock (&object_mutex);
|
||
|
||
if (f)
|
||
{
|
||
int encoding;
|
||
_Unwind_Ptr func;
|
||
|
||
bases->tbase = ob->tbase;
|
||
bases->dbase = ob->dbase;
|
||
|
||
encoding = ob->s.b.encoding;
|
||
if (ob->s.b.mixed_encoding)
|
||
encoding = get_fde_encoding (f);
|
||
read_encoded_value_with_base (encoding, base_from_object (encoding, ob),
|
||
f->pc_begin, &func);
|
||
bases->func = (void *) func;
|
||
}
|
||
|
||
return f;
|
||
}
|
||
|
||
#endif
|