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/* Copyright (C) 2000-2016 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@cygnus.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/>. */
/* Locate the FDE entry for a given address, using glibc ld.so routines
to avoid register/deregister calls at DSO load/unload. */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#include "config.h"
#include <stddef.h>
#include <stdlib.h>
#include <link.h>
#include "unwind-ia64.h"
#if __GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 2) \
|| (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && !defined(DT_CONFIG))
# error You need GLIBC 2.2.4 or later on IA-64 Linux
#endif
struct unw_ia64_callback_data
{
Elf64_Addr pc;
unsigned long *segment_base;
unsigned long *gp;
struct unw_table_entry *ret;
};
static int
_Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr)
{
struct unw_ia64_callback_data *data = (struct unw_ia64_callback_data *) ptr;
const Elf64_Phdr *phdr, *p_unwind, *p_dynamic;
long n, match;
Elf64_Addr load_base, seg_base;
struct unw_table_entry *f_base, *f;
size_t lo, hi;
/* Make sure struct dl_phdr_info is at least as big as we need. */
if (size < offsetof (struct dl_phdr_info, dlpi_phnum)
+ sizeof (info->dlpi_phnum))
return -1;
match = 0;
phdr = info->dlpi_phdr;
load_base = info->dlpi_addr;
p_unwind = NULL;
p_dynamic = NULL;
seg_base = ~(Elf64_Addr) 0;
/* See if PC falls into one of the loaded segments. Find the unwind
segment at the same time. */
for (n = info->dlpi_phnum; --n >= 0; phdr++)
{
if (phdr->p_type == PT_LOAD)
{
Elf64_Addr vaddr = phdr->p_vaddr + load_base;
if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz)
match = 1;
if (vaddr < seg_base)
seg_base = vaddr;
}
else if (phdr->p_type == PT_IA_64_UNWIND)
p_unwind = phdr;
else if (phdr->p_type == PT_DYNAMIC)
p_dynamic = phdr;
}
if (!match || !p_unwind)
return 0;
/* Search for the FDE within the unwind segment. */
f_base = (struct unw_table_entry *) (p_unwind->p_vaddr + load_base);
lo = 0;
hi = p_unwind->p_memsz / sizeof (struct unw_table_entry);
while (lo < hi)
{
size_t mid = (lo + hi) / 2;
f = f_base + mid;
if (data->pc < f->start_offset + seg_base)
hi = mid;
else if (data->pc >= f->end_offset + seg_base)
lo = mid + 1;
else
goto found;
}
/* No need to search for further libraries when we know pc is contained
in this library. */
return 1;
found:
*data->segment_base = seg_base;
*data->gp = 0;
data->ret = f;
if (p_dynamic)
{
/* For dynamically linked executables and shared libraries,
DT_PLTGOT is the gp value for that object. */
Elf64_Dyn *dyn = (Elf64_Dyn *)(p_dynamic->p_vaddr + load_base);
for (; dyn->d_tag != DT_NULL ; dyn++)
if (dyn->d_tag == DT_PLTGOT)
{
/* On IA-64, _DYNAMIC is writable and GLIBC has relocated it. */
*data->gp = dyn->d_un.d_ptr;
break;
}
}
else
{
/* Otherwise this is a static executable with no _DYNAMIC.
The gp is constant program-wide. */
register unsigned long gp __asm__("gp");
*data->gp = gp;
}
return 1;
}
/* Return a pointer to the unwind table entry for the function
containing PC. */
struct unw_table_entry *
_Unwind_FindTableEntry (void *pc, unw_word *segment_base, unw_word *gp,
struct unw_table_entry *ent ATTRIBUTE_UNUSED)
{
struct unw_ia64_callback_data data;
data.pc = (Elf64_Addr) pc;
data.segment_base = segment_base;
data.gp = gp;
data.ret = NULL;
if (dl_iterate_phdr (_Unwind_IteratePhdrCallback, &data) < 0)
return NULL;
return data.ret;
}
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