1090 lines
34 KiB
C
1090 lines
34 KiB
C
/* Read ELF (Executable and Linking Format) object files for GDB.
|
||
|
||
Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
|
||
2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
|
||
Free Software Foundation, Inc.
|
||
|
||
Written by Fred Fish at Cygnus Support.
|
||
|
||
This file is part of GDB.
|
||
|
||
This program 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 of the License, or
|
||
(at your option) any later version.
|
||
|
||
This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
|
||
|
||
#include "defs.h"
|
||
#include "bfd.h"
|
||
#include "gdb_string.h"
|
||
#include "elf-bfd.h"
|
||
#include "elf/common.h"
|
||
#include "elf/internal.h"
|
||
#include "elf/mips.h"
|
||
#include "symtab.h"
|
||
#include "symfile.h"
|
||
#include "objfiles.h"
|
||
#include "buildsym.h"
|
||
#include "stabsread.h"
|
||
#include "gdb-stabs.h"
|
||
#include "complaints.h"
|
||
#include "demangle.h"
|
||
#include "psympriv.h"
|
||
|
||
extern void _initialize_elfread (void);
|
||
|
||
/* Forward declaration. */
|
||
static const struct sym_fns elf_sym_fns_gdb_index;
|
||
|
||
/* The struct elfinfo is available only during ELF symbol table and
|
||
psymtab reading. It is destroyed at the completion of psymtab-reading.
|
||
It's local to elf_symfile_read. */
|
||
|
||
struct elfinfo
|
||
{
|
||
asection *stabsect; /* Section pointer for .stab section */
|
||
asection *stabindexsect; /* Section pointer for .stab.index section */
|
||
asection *mdebugsect; /* Section pointer for .mdebug section */
|
||
};
|
||
|
||
static void free_elfinfo (void *);
|
||
|
||
/* Locate the segments in ABFD. */
|
||
|
||
static struct symfile_segment_data *
|
||
elf_symfile_segments (bfd *abfd)
|
||
{
|
||
Elf_Internal_Phdr *phdrs, **segments;
|
||
long phdrs_size;
|
||
int num_phdrs, num_segments, num_sections, i;
|
||
asection *sect;
|
||
struct symfile_segment_data *data;
|
||
|
||
phdrs_size = bfd_get_elf_phdr_upper_bound (abfd);
|
||
if (phdrs_size == -1)
|
||
return NULL;
|
||
|
||
phdrs = alloca (phdrs_size);
|
||
num_phdrs = bfd_get_elf_phdrs (abfd, phdrs);
|
||
if (num_phdrs == -1)
|
||
return NULL;
|
||
|
||
num_segments = 0;
|
||
segments = alloca (sizeof (Elf_Internal_Phdr *) * num_phdrs);
|
||
for (i = 0; i < num_phdrs; i++)
|
||
if (phdrs[i].p_type == PT_LOAD)
|
||
segments[num_segments++] = &phdrs[i];
|
||
|
||
if (num_segments == 0)
|
||
return NULL;
|
||
|
||
data = XZALLOC (struct symfile_segment_data);
|
||
data->num_segments = num_segments;
|
||
data->segment_bases = XCALLOC (num_segments, CORE_ADDR);
|
||
data->segment_sizes = XCALLOC (num_segments, CORE_ADDR);
|
||
|
||
for (i = 0; i < num_segments; i++)
|
||
{
|
||
data->segment_bases[i] = segments[i]->p_vaddr;
|
||
data->segment_sizes[i] = segments[i]->p_memsz;
|
||
}
|
||
|
||
num_sections = bfd_count_sections (abfd);
|
||
data->segment_info = XCALLOC (num_sections, int);
|
||
|
||
for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next)
|
||
{
|
||
int j;
|
||
CORE_ADDR vma;
|
||
|
||
if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
|
||
continue;
|
||
|
||
vma = bfd_get_section_vma (abfd, sect);
|
||
|
||
for (j = 0; j < num_segments; j++)
|
||
if (segments[j]->p_memsz > 0
|
||
&& vma >= segments[j]->p_vaddr
|
||
&& (vma - segments[j]->p_vaddr) < segments[j]->p_memsz)
|
||
{
|
||
data->segment_info[i] = j + 1;
|
||
break;
|
||
}
|
||
|
||
/* We should have found a segment for every non-empty section.
|
||
If we haven't, we will not relocate this section by any
|
||
offsets we apply to the segments. As an exception, do not
|
||
warn about SHT_NOBITS sections; in normal ELF execution
|
||
environments, SHT_NOBITS means zero-initialized and belongs
|
||
in a segment, but in no-OS environments some tools (e.g. ARM
|
||
RealView) use SHT_NOBITS for uninitialized data. Since it is
|
||
uninitialized, it doesn't need a program header. Such
|
||
binaries are not relocatable. */
|
||
if (bfd_get_section_size (sect) > 0 && j == num_segments
|
||
&& (bfd_get_section_flags (abfd, sect) & SEC_LOAD) != 0)
|
||
warning (_("Loadable segment \"%s\" outside of ELF segments"),
|
||
bfd_section_name (abfd, sect));
|
||
}
|
||
|
||
return data;
|
||
}
|
||
|
||
/* We are called once per section from elf_symfile_read. We
|
||
need to examine each section we are passed, check to see
|
||
if it is something we are interested in processing, and
|
||
if so, stash away some access information for the section.
|
||
|
||
For now we recognize the dwarf debug information sections and
|
||
line number sections from matching their section names. The
|
||
ELF definition is no real help here since it has no direct
|
||
knowledge of DWARF (by design, so any debugging format can be
|
||
used).
|
||
|
||
We also recognize the ".stab" sections used by the Sun compilers
|
||
released with Solaris 2.
|
||
|
||
FIXME: The section names should not be hardwired strings (what
|
||
should they be? I don't think most object file formats have enough
|
||
section flags to specify what kind of debug section it is
|
||
-kingdon). */
|
||
|
||
static void
|
||
elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip)
|
||
{
|
||
struct elfinfo *ei;
|
||
|
||
ei = (struct elfinfo *) eip;
|
||
if (strcmp (sectp->name, ".stab") == 0)
|
||
{
|
||
ei->stabsect = sectp;
|
||
}
|
||
else if (strcmp (sectp->name, ".stab.index") == 0)
|
||
{
|
||
ei->stabindexsect = sectp;
|
||
}
|
||
else if (strcmp (sectp->name, ".mdebug") == 0)
|
||
{
|
||
ei->mdebugsect = sectp;
|
||
}
|
||
}
|
||
|
||
static struct minimal_symbol *
|
||
record_minimal_symbol (const char *name, int name_len, int copy_name,
|
||
CORE_ADDR address,
|
||
enum minimal_symbol_type ms_type,
|
||
asection *bfd_section, struct objfile *objfile)
|
||
{
|
||
struct gdbarch *gdbarch = get_objfile_arch (objfile);
|
||
|
||
if (ms_type == mst_text || ms_type == mst_file_text)
|
||
address = gdbarch_smash_text_address (gdbarch, address);
|
||
|
||
return prim_record_minimal_symbol_full (name, name_len, copy_name, address,
|
||
ms_type, bfd_section->index,
|
||
bfd_section, objfile);
|
||
}
|
||
|
||
/*
|
||
|
||
LOCAL FUNCTION
|
||
|
||
elf_symtab_read -- read the symbol table of an ELF file
|
||
|
||
SYNOPSIS
|
||
|
||
void elf_symtab_read (struct objfile *objfile, int type,
|
||
long number_of_symbols, asymbol **symbol_table)
|
||
|
||
DESCRIPTION
|
||
|
||
Given an objfile, a symbol table, and a flag indicating whether the
|
||
symbol table contains regular, dynamic, or synthetic symbols, add all
|
||
the global function and data symbols to the minimal symbol table.
|
||
|
||
In stabs-in-ELF, as implemented by Sun, there are some local symbols
|
||
defined in the ELF symbol table, which can be used to locate
|
||
the beginnings of sections from each ".o" file that was linked to
|
||
form the executable objfile. We gather any such info and record it
|
||
in data structures hung off the objfile's private data.
|
||
|
||
*/
|
||
|
||
#define ST_REGULAR 0
|
||
#define ST_DYNAMIC 1
|
||
#define ST_SYNTHETIC 2
|
||
|
||
static void
|
||
elf_symtab_read (struct objfile *objfile, int type,
|
||
long number_of_symbols, asymbol **symbol_table,
|
||
int copy_names)
|
||
{
|
||
struct gdbarch *gdbarch = get_objfile_arch (objfile);
|
||
asymbol *sym;
|
||
long i;
|
||
CORE_ADDR symaddr;
|
||
CORE_ADDR offset;
|
||
enum minimal_symbol_type ms_type;
|
||
/* If sectinfo is nonNULL, it contains section info that should end up
|
||
filed in the objfile. */
|
||
struct stab_section_info *sectinfo = NULL;
|
||
/* If filesym is nonzero, it points to a file symbol, but we haven't
|
||
seen any section info for it yet. */
|
||
asymbol *filesym = 0;
|
||
/* Name of filesym. This is either a constant string or is saved on
|
||
the objfile's obstack. */
|
||
char *filesymname = "";
|
||
struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
|
||
int stripped = (bfd_get_symcount (objfile->obfd) == 0);
|
||
|
||
for (i = 0; i < number_of_symbols; i++)
|
||
{
|
||
sym = symbol_table[i];
|
||
if (sym->name == NULL || *sym->name == '\0')
|
||
{
|
||
/* Skip names that don't exist (shouldn't happen), or names
|
||
that are null strings (may happen). */
|
||
continue;
|
||
}
|
||
|
||
/* Skip "special" symbols, e.g. ARM mapping symbols. These are
|
||
symbols which do not correspond to objects in the symbol table,
|
||
but have some other target-specific meaning. */
|
||
if (bfd_is_target_special_symbol (objfile->obfd, sym))
|
||
{
|
||
if (gdbarch_record_special_symbol_p (gdbarch))
|
||
gdbarch_record_special_symbol (gdbarch, objfile, sym);
|
||
continue;
|
||
}
|
||
|
||
offset = ANOFFSET (objfile->section_offsets, sym->section->index);
|
||
if (type == ST_DYNAMIC
|
||
&& sym->section == &bfd_und_section
|
||
&& (sym->flags & BSF_FUNCTION))
|
||
{
|
||
struct minimal_symbol *msym;
|
||
bfd *abfd = objfile->obfd;
|
||
asection *sect;
|
||
|
||
/* Symbol is a reference to a function defined in
|
||
a shared library.
|
||
If its value is non zero then it is usually the address
|
||
of the corresponding entry in the procedure linkage table,
|
||
plus the desired section offset.
|
||
If its value is zero then the dynamic linker has to resolve
|
||
the symbol. We are unable to find any meaningful address
|
||
for this symbol in the executable file, so we skip it. */
|
||
symaddr = sym->value;
|
||
if (symaddr == 0)
|
||
continue;
|
||
|
||
/* sym->section is the undefined section. However, we want to
|
||
record the section where the PLT stub resides with the
|
||
minimal symbol. Search the section table for the one that
|
||
covers the stub's address. */
|
||
for (sect = abfd->sections; sect != NULL; sect = sect->next)
|
||
{
|
||
if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
|
||
continue;
|
||
|
||
if (symaddr >= bfd_get_section_vma (abfd, sect)
|
||
&& symaddr < bfd_get_section_vma (abfd, sect)
|
||
+ bfd_get_section_size (sect))
|
||
break;
|
||
}
|
||
if (!sect)
|
||
continue;
|
||
|
||
symaddr += ANOFFSET (objfile->section_offsets, sect->index);
|
||
|
||
msym = record_minimal_symbol
|
||
(sym->name, strlen (sym->name), copy_names,
|
||
symaddr, mst_solib_trampoline, sect, objfile);
|
||
if (msym != NULL)
|
||
msym->filename = filesymname;
|
||
continue;
|
||
}
|
||
|
||
/* If it is a nonstripped executable, do not enter dynamic
|
||
symbols, as the dynamic symbol table is usually a subset
|
||
of the main symbol table. */
|
||
if (type == ST_DYNAMIC && !stripped)
|
||
continue;
|
||
if (sym->flags & BSF_FILE)
|
||
{
|
||
/* STT_FILE debugging symbol that helps stabs-in-elf debugging.
|
||
Chain any old one onto the objfile; remember new sym. */
|
||
if (sectinfo != NULL)
|
||
{
|
||
sectinfo->next = dbx->stab_section_info;
|
||
dbx->stab_section_info = sectinfo;
|
||
sectinfo = NULL;
|
||
}
|
||
filesym = sym;
|
||
filesymname =
|
||
obsavestring ((char *) filesym->name, strlen (filesym->name),
|
||
&objfile->objfile_obstack);
|
||
}
|
||
else if (sym->flags & BSF_SECTION_SYM)
|
||
continue;
|
||
else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
|
||
{
|
||
struct minimal_symbol *msym;
|
||
|
||
/* Select global/local/weak symbols. Note that bfd puts abs
|
||
symbols in their own section, so all symbols we are
|
||
interested in will have a section. */
|
||
/* Bfd symbols are section relative. */
|
||
symaddr = sym->value + sym->section->vma;
|
||
/* Relocate all non-absolute and non-TLS symbols by the
|
||
section offset. */
|
||
if (sym->section != &bfd_abs_section
|
||
&& !(sym->section->flags & SEC_THREAD_LOCAL))
|
||
{
|
||
symaddr += offset;
|
||
}
|
||
/* For non-absolute symbols, use the type of the section
|
||
they are relative to, to intuit text/data. Bfd provides
|
||
no way of figuring this out for absolute symbols. */
|
||
if (sym->section == &bfd_abs_section)
|
||
{
|
||
/* This is a hack to get the minimal symbol type
|
||
right for Irix 5, which has absolute addresses
|
||
with special section indices for dynamic symbols.
|
||
|
||
NOTE: uweigand-20071112: Synthetic symbols do not
|
||
have an ELF-private part, so do not touch those. */
|
||
unsigned int shndx = type == ST_SYNTHETIC ? 0 :
|
||
((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
|
||
|
||
switch (shndx)
|
||
{
|
||
case SHN_MIPS_TEXT:
|
||
ms_type = mst_text;
|
||
break;
|
||
case SHN_MIPS_DATA:
|
||
ms_type = mst_data;
|
||
break;
|
||
case SHN_MIPS_ACOMMON:
|
||
ms_type = mst_bss;
|
||
break;
|
||
default:
|
||
ms_type = mst_abs;
|
||
}
|
||
|
||
/* If it is an Irix dynamic symbol, skip section name
|
||
symbols, relocate all others by section offset. */
|
||
if (ms_type != mst_abs)
|
||
{
|
||
if (sym->name[0] == '.')
|
||
continue;
|
||
symaddr += offset;
|
||
}
|
||
}
|
||
else if (sym->section->flags & SEC_CODE)
|
||
{
|
||
if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
|
||
{
|
||
ms_type = mst_text;
|
||
}
|
||
else if ((sym->name[0] == '.' && sym->name[1] == 'L')
|
||
|| ((sym->flags & BSF_LOCAL)
|
||
&& sym->name[0] == '$'
|
||
&& sym->name[1] == 'L'))
|
||
/* Looks like a compiler-generated label. Skip
|
||
it. The assembler should be skipping these (to
|
||
keep executables small), but apparently with
|
||
gcc on the (deleted) delta m88k SVR4, it loses.
|
||
So to have us check too should be harmless (but
|
||
I encourage people to fix this in the assembler
|
||
instead of adding checks here). */
|
||
continue;
|
||
else
|
||
{
|
||
ms_type = mst_file_text;
|
||
}
|
||
}
|
||
else if (sym->section->flags & SEC_ALLOC)
|
||
{
|
||
if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
|
||
{
|
||
if (sym->section->flags & SEC_LOAD)
|
||
{
|
||
ms_type = mst_data;
|
||
}
|
||
else
|
||
{
|
||
ms_type = mst_bss;
|
||
}
|
||
}
|
||
else if (sym->flags & BSF_LOCAL)
|
||
{
|
||
/* Named Local variable in a Data section.
|
||
Check its name for stabs-in-elf. */
|
||
int special_local_sect;
|
||
|
||
if (strcmp ("Bbss.bss", sym->name) == 0)
|
||
special_local_sect = SECT_OFF_BSS (objfile);
|
||
else if (strcmp ("Ddata.data", sym->name) == 0)
|
||
special_local_sect = SECT_OFF_DATA (objfile);
|
||
else if (strcmp ("Drodata.rodata", sym->name) == 0)
|
||
special_local_sect = SECT_OFF_RODATA (objfile);
|
||
else
|
||
special_local_sect = -1;
|
||
if (special_local_sect >= 0)
|
||
{
|
||
/* Found a special local symbol. Allocate a
|
||
sectinfo, if needed, and fill it in. */
|
||
if (sectinfo == NULL)
|
||
{
|
||
int max_index;
|
||
size_t size;
|
||
|
||
max_index = SECT_OFF_BSS (objfile);
|
||
if (objfile->sect_index_data > max_index)
|
||
max_index = objfile->sect_index_data;
|
||
if (objfile->sect_index_rodata > max_index)
|
||
max_index = objfile->sect_index_rodata;
|
||
|
||
/* max_index is the largest index we'll
|
||
use into this array, so we must
|
||
allocate max_index+1 elements for it.
|
||
However, 'struct stab_section_info'
|
||
already includes one element, so we
|
||
need to allocate max_index aadditional
|
||
elements. */
|
||
size = (sizeof (struct stab_section_info)
|
||
+ (sizeof (CORE_ADDR)
|
||
* max_index));
|
||
sectinfo = (struct stab_section_info *)
|
||
xmalloc (size);
|
||
memset (sectinfo, 0, size);
|
||
sectinfo->num_sections = max_index;
|
||
if (filesym == NULL)
|
||
{
|
||
complaint (&symfile_complaints,
|
||
_("elf/stab section information %s "
|
||
"without a preceding file symbol"),
|
||
sym->name);
|
||
}
|
||
else
|
||
{
|
||
sectinfo->filename =
|
||
(char *) filesym->name;
|
||
}
|
||
}
|
||
if (sectinfo->sections[special_local_sect] != 0)
|
||
complaint (&symfile_complaints,
|
||
_("duplicated elf/stab section "
|
||
"information for %s"),
|
||
sectinfo->filename);
|
||
/* BFD symbols are section relative. */
|
||
symaddr = sym->value + sym->section->vma;
|
||
/* Relocate non-absolute symbols by the
|
||
section offset. */
|
||
if (sym->section != &bfd_abs_section)
|
||
symaddr += offset;
|
||
sectinfo->sections[special_local_sect] = symaddr;
|
||
/* The special local symbols don't go in the
|
||
minimal symbol table, so ignore this one. */
|
||
continue;
|
||
}
|
||
/* Not a special stabs-in-elf symbol, do regular
|
||
symbol processing. */
|
||
if (sym->section->flags & SEC_LOAD)
|
||
{
|
||
ms_type = mst_file_data;
|
||
}
|
||
else
|
||
{
|
||
ms_type = mst_file_bss;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
ms_type = mst_unknown;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* FIXME: Solaris2 shared libraries include lots of
|
||
odd "absolute" and "undefined" symbols, that play
|
||
hob with actions like finding what function the PC
|
||
is in. Ignore them if they aren't text, data, or bss. */
|
||
/* ms_type = mst_unknown; */
|
||
continue; /* Skip this symbol. */
|
||
}
|
||
msym = record_minimal_symbol
|
||
(sym->name, strlen (sym->name), copy_names, symaddr,
|
||
ms_type, sym->section, objfile);
|
||
|
||
if (msym)
|
||
{
|
||
/* Pass symbol size field in via BFD. FIXME!!! */
|
||
elf_symbol_type *elf_sym;
|
||
|
||
/* NOTE: uweigand-20071112: A synthetic symbol does not have an
|
||
ELF-private part. However, in some cases (e.g. synthetic
|
||
'dot' symbols on ppc64) the udata.p entry is set to point back
|
||
to the original ELF symbol it was derived from. Get the size
|
||
from that symbol. */
|
||
if (type != ST_SYNTHETIC)
|
||
elf_sym = (elf_symbol_type *) sym;
|
||
else
|
||
elf_sym = (elf_symbol_type *) sym->udata.p;
|
||
|
||
if (elf_sym)
|
||
MSYMBOL_SIZE(msym) = elf_sym->internal_elf_sym.st_size;
|
||
|
||
msym->filename = filesymname;
|
||
gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
|
||
}
|
||
|
||
/* For @plt symbols, also record a trampoline to the
|
||
destination symbol. The @plt symbol will be used in
|
||
disassembly, and the trampoline will be used when we are
|
||
trying to find the target. */
|
||
if (msym && ms_type == mst_text && type == ST_SYNTHETIC)
|
||
{
|
||
int len = strlen (sym->name);
|
||
|
||
if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0)
|
||
{
|
||
struct minimal_symbol *mtramp;
|
||
|
||
mtramp = record_minimal_symbol (sym->name, len - 4, 1,
|
||
symaddr,
|
||
mst_solib_trampoline,
|
||
sym->section, objfile);
|
||
if (mtramp)
|
||
{
|
||
MSYMBOL_SIZE (mtramp) = MSYMBOL_SIZE (msym);
|
||
mtramp->filename = filesymname;
|
||
gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
struct build_id
|
||
{
|
||
size_t size;
|
||
gdb_byte data[1];
|
||
};
|
||
|
||
/* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
|
||
|
||
static struct build_id *
|
||
build_id_bfd_get (bfd *abfd)
|
||
{
|
||
struct build_id *retval;
|
||
|
||
if (!bfd_check_format (abfd, bfd_object)
|
||
|| bfd_get_flavour (abfd) != bfd_target_elf_flavour
|
||
|| elf_tdata (abfd)->build_id == NULL)
|
||
return NULL;
|
||
|
||
retval = xmalloc (sizeof *retval - 1 + elf_tdata (abfd)->build_id_size);
|
||
retval->size = elf_tdata (abfd)->build_id_size;
|
||
memcpy (retval->data, elf_tdata (abfd)->build_id, retval->size);
|
||
|
||
return retval;
|
||
}
|
||
|
||
/* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */
|
||
|
||
static int
|
||
build_id_verify (const char *filename, struct build_id *check)
|
||
{
|
||
bfd *abfd;
|
||
struct build_id *found = NULL;
|
||
int retval = 0;
|
||
|
||
/* We expect to be silent on the non-existing files. */
|
||
abfd = bfd_open_maybe_remote (filename);
|
||
if (abfd == NULL)
|
||
return 0;
|
||
|
||
found = build_id_bfd_get (abfd);
|
||
|
||
if (found == NULL)
|
||
warning (_("File \"%s\" has no build-id, file skipped"), filename);
|
||
else if (found->size != check->size
|
||
|| memcmp (found->data, check->data, found->size) != 0)
|
||
warning (_("File \"%s\" has a different build-id, file skipped"),
|
||
filename);
|
||
else
|
||
retval = 1;
|
||
|
||
gdb_bfd_close_or_warn (abfd);
|
||
|
||
xfree (found);
|
||
|
||
return retval;
|
||
}
|
||
|
||
static char *
|
||
build_id_to_debug_filename (struct build_id *build_id)
|
||
{
|
||
char *link, *debugdir, *retval = NULL;
|
||
|
||
/* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
|
||
link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
|
||
+ 2 * build_id->size + (sizeof ".debug" - 1) + 1);
|
||
|
||
/* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
|
||
cause "/.build-id/..." lookups. */
|
||
|
||
debugdir = debug_file_directory;
|
||
do
|
||
{
|
||
char *s, *debugdir_end;
|
||
gdb_byte *data = build_id->data;
|
||
size_t size = build_id->size;
|
||
|
||
while (*debugdir == DIRNAME_SEPARATOR)
|
||
debugdir++;
|
||
|
||
debugdir_end = strchr (debugdir, DIRNAME_SEPARATOR);
|
||
if (debugdir_end == NULL)
|
||
debugdir_end = &debugdir[strlen (debugdir)];
|
||
|
||
memcpy (link, debugdir, debugdir_end - debugdir);
|
||
s = &link[debugdir_end - debugdir];
|
||
s += sprintf (s, "/.build-id/");
|
||
if (size > 0)
|
||
{
|
||
size--;
|
||
s += sprintf (s, "%02x", (unsigned) *data++);
|
||
}
|
||
if (size > 0)
|
||
*s++ = '/';
|
||
while (size-- > 0)
|
||
s += sprintf (s, "%02x", (unsigned) *data++);
|
||
strcpy (s, ".debug");
|
||
|
||
/* lrealpath() is expensive even for the usually non-existent files. */
|
||
if (access (link, F_OK) == 0)
|
||
retval = lrealpath (link);
|
||
|
||
if (retval != NULL && !build_id_verify (retval, build_id))
|
||
{
|
||
xfree (retval);
|
||
retval = NULL;
|
||
}
|
||
|
||
if (retval != NULL)
|
||
break;
|
||
|
||
debugdir = debugdir_end;
|
||
}
|
||
while (*debugdir != 0);
|
||
|
||
return retval;
|
||
}
|
||
|
||
static char *
|
||
find_separate_debug_file_by_buildid (struct objfile *objfile)
|
||
{
|
||
struct build_id *build_id;
|
||
|
||
build_id = build_id_bfd_get (objfile->obfd);
|
||
if (build_id != NULL)
|
||
{
|
||
char *build_id_name;
|
||
|
||
build_id_name = build_id_to_debug_filename (build_id);
|
||
xfree (build_id);
|
||
/* Prevent looping on a stripped .debug file. */
|
||
if (build_id_name != NULL && strcmp (build_id_name, objfile->name) == 0)
|
||
{
|
||
warning (_("\"%s\": separate debug info file has no debug info"),
|
||
build_id_name);
|
||
xfree (build_id_name);
|
||
}
|
||
else if (build_id_name != NULL)
|
||
return build_id_name;
|
||
}
|
||
return NULL;
|
||
}
|
||
|
||
/* Scan and build partial symbols for a symbol file.
|
||
We have been initialized by a call to elf_symfile_init, which
|
||
currently does nothing.
|
||
|
||
SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
|
||
in each section. We simplify it down to a single offset for all
|
||
symbols. FIXME.
|
||
|
||
This function only does the minimum work necessary for letting the
|
||
user "name" things symbolically; it does not read the entire symtab.
|
||
Instead, it reads the external and static symbols and puts them in partial
|
||
symbol tables. When more extensive information is requested of a
|
||
file, the corresponding partial symbol table is mutated into a full
|
||
fledged symbol table by going back and reading the symbols
|
||
for real.
|
||
|
||
We look for sections with specific names, to tell us what debug
|
||
format to look for: FIXME!!!
|
||
|
||
elfstab_build_psymtabs() handles STABS symbols;
|
||
mdebug_build_psymtabs() handles ECOFF debugging information.
|
||
|
||
Note that ELF files have a "minimal" symbol table, which looks a lot
|
||
like a COFF symbol table, but has only the minimal information necessary
|
||
for linking. We process this also, and use the information to
|
||
build gdb's minimal symbol table. This gives us some minimal debugging
|
||
capability even for files compiled without -g. */
|
||
|
||
static void
|
||
elf_symfile_read (struct objfile *objfile, int symfile_flags)
|
||
{
|
||
bfd *abfd = objfile->obfd;
|
||
struct elfinfo ei;
|
||
struct cleanup *back_to;
|
||
long symcount = 0, dynsymcount = 0, synthcount, storage_needed;
|
||
asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
|
||
asymbol *synthsyms;
|
||
|
||
init_minimal_symbol_collection ();
|
||
back_to = make_cleanup_discard_minimal_symbols ();
|
||
|
||
memset ((char *) &ei, 0, sizeof (ei));
|
||
|
||
/* Allocate struct to keep track of the symfile */
|
||
objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *)
|
||
xmalloc (sizeof (struct dbx_symfile_info));
|
||
memset ((char *) objfile->deprecated_sym_stab_info,
|
||
0, sizeof (struct dbx_symfile_info));
|
||
make_cleanup (free_elfinfo, (void *) objfile);
|
||
|
||
/* Process the normal ELF symbol table first. This may write some
|
||
chain of info into the dbx_symfile_info in
|
||
objfile->deprecated_sym_stab_info, which can later be used by
|
||
elfstab_offset_sections. */
|
||
|
||
storage_needed = bfd_get_symtab_upper_bound (objfile->obfd);
|
||
if (storage_needed < 0)
|
||
error (_("Can't read symbols from %s: %s"),
|
||
bfd_get_filename (objfile->obfd),
|
||
bfd_errmsg (bfd_get_error ()));
|
||
|
||
if (storage_needed > 0)
|
||
{
|
||
symbol_table = (asymbol **) xmalloc (storage_needed);
|
||
make_cleanup (xfree, symbol_table);
|
||
symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table);
|
||
|
||
if (symcount < 0)
|
||
error (_("Can't read symbols from %s: %s"),
|
||
bfd_get_filename (objfile->obfd),
|
||
bfd_errmsg (bfd_get_error ()));
|
||
|
||
elf_symtab_read (objfile, ST_REGULAR, symcount, symbol_table, 0);
|
||
}
|
||
|
||
/* Add the dynamic symbols. */
|
||
|
||
storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd);
|
||
|
||
if (storage_needed > 0)
|
||
{
|
||
/* Memory gets permanently referenced from ABFD after
|
||
bfd_get_synthetic_symtab so it must not get freed before ABFD gets.
|
||
It happens only in the case when elf_slurp_reloc_table sees
|
||
asection->relocation NULL. Determining which section is asection is
|
||
done by _bfd_elf_get_synthetic_symtab which is all a bfd
|
||
implementation detail, though. */
|
||
|
||
dyn_symbol_table = bfd_alloc (abfd, storage_needed);
|
||
dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd,
|
||
dyn_symbol_table);
|
||
|
||
if (dynsymcount < 0)
|
||
error (_("Can't read symbols from %s: %s"),
|
||
bfd_get_filename (objfile->obfd),
|
||
bfd_errmsg (bfd_get_error ()));
|
||
|
||
elf_symtab_read (objfile, ST_DYNAMIC, dynsymcount, dyn_symbol_table, 0);
|
||
}
|
||
|
||
/* Add synthetic symbols - for instance, names for any PLT entries. */
|
||
|
||
synthcount = bfd_get_synthetic_symtab (abfd, symcount, symbol_table,
|
||
dynsymcount, dyn_symbol_table,
|
||
&synthsyms);
|
||
if (synthcount > 0)
|
||
{
|
||
asymbol **synth_symbol_table;
|
||
long i;
|
||
|
||
make_cleanup (xfree, synthsyms);
|
||
synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount);
|
||
for (i = 0; i < synthcount; i++)
|
||
synth_symbol_table[i] = synthsyms + i;
|
||
make_cleanup (xfree, synth_symbol_table);
|
||
elf_symtab_read (objfile, ST_SYNTHETIC, synthcount,
|
||
synth_symbol_table, 1);
|
||
}
|
||
|
||
/* Install any minimal symbols that have been collected as the current
|
||
minimal symbols for this objfile. The debug readers below this point
|
||
should not generate new minimal symbols; if they do it's their
|
||
responsibility to install them. "mdebug" appears to be the only one
|
||
which will do this. */
|
||
|
||
install_minimal_symbols (objfile);
|
||
do_cleanups (back_to);
|
||
|
||
/* Now process debugging information, which is contained in
|
||
special ELF sections. */
|
||
|
||
/* We first have to find them... */
|
||
bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei);
|
||
|
||
/* ELF debugging information is inserted into the psymtab in the
|
||
order of least informative first - most informative last. Since
|
||
the psymtab table is searched `most recent insertion first' this
|
||
increases the probability that more detailed debug information
|
||
for a section is found.
|
||
|
||
For instance, an object file might contain both .mdebug (XCOFF)
|
||
and .debug_info (DWARF2) sections then .mdebug is inserted first
|
||
(searched last) and DWARF2 is inserted last (searched first). If
|
||
we don't do this then the XCOFF info is found first - for code in
|
||
an included file XCOFF info is useless. */
|
||
|
||
if (ei.mdebugsect)
|
||
{
|
||
const struct ecoff_debug_swap *swap;
|
||
|
||
/* .mdebug section, presumably holding ECOFF debugging
|
||
information. */
|
||
swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
|
||
if (swap)
|
||
elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect);
|
||
}
|
||
if (ei.stabsect)
|
||
{
|
||
asection *str_sect;
|
||
|
||
/* Stab sections have an associated string table that looks like
|
||
a separate section. */
|
||
str_sect = bfd_get_section_by_name (abfd, ".stabstr");
|
||
|
||
/* FIXME should probably warn about a stab section without a stabstr. */
|
||
if (str_sect)
|
||
elfstab_build_psymtabs (objfile,
|
||
ei.stabsect,
|
||
str_sect->filepos,
|
||
bfd_section_size (abfd, str_sect));
|
||
}
|
||
|
||
if (dwarf2_has_info (objfile) && dwarf2_initialize_objfile (objfile))
|
||
objfile->sf = &elf_sym_fns_gdb_index;
|
||
|
||
/* If the file has its own symbol tables it has no separate debug
|
||
info. `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to
|
||
SYMTABS/PSYMTABS. `.gnu_debuglink' may no longer be present with
|
||
`.note.gnu.build-id'. */
|
||
if (!objfile_has_partial_symbols (objfile))
|
||
{
|
||
char *debugfile;
|
||
|
||
debugfile = find_separate_debug_file_by_buildid (objfile);
|
||
|
||
if (debugfile == NULL)
|
||
debugfile = find_separate_debug_file_by_debuglink (objfile);
|
||
|
||
if (debugfile)
|
||
{
|
||
bfd *abfd = symfile_bfd_open (debugfile);
|
||
|
||
symbol_file_add_separate (abfd, symfile_flags, objfile);
|
||
xfree (debugfile);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* This cleans up the objfile's deprecated_sym_stab_info pointer, and
|
||
the chain of stab_section_info's, that might be dangling from
|
||
it. */
|
||
|
||
static void
|
||
free_elfinfo (void *objp)
|
||
{
|
||
struct objfile *objfile = (struct objfile *) objp;
|
||
struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info;
|
||
struct stab_section_info *ssi, *nssi;
|
||
|
||
ssi = dbxinfo->stab_section_info;
|
||
while (ssi)
|
||
{
|
||
nssi = ssi->next;
|
||
xfree (ssi);
|
||
ssi = nssi;
|
||
}
|
||
|
||
dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */
|
||
}
|
||
|
||
|
||
/* Initialize anything that needs initializing when a completely new symbol
|
||
file is specified (not just adding some symbols from another file, e.g. a
|
||
shared library).
|
||
|
||
We reinitialize buildsym, since we may be reading stabs from an ELF
|
||
file. */
|
||
|
||
static void
|
||
elf_new_init (struct objfile *ignore)
|
||
{
|
||
stabsread_new_init ();
|
||
buildsym_new_init ();
|
||
}
|
||
|
||
/* Perform any local cleanups required when we are done with a particular
|
||
objfile. I.E, we are in the process of discarding all symbol information
|
||
for an objfile, freeing up all memory held for it, and unlinking the
|
||
objfile struct from the global list of known objfiles. */
|
||
|
||
static void
|
||
elf_symfile_finish (struct objfile *objfile)
|
||
{
|
||
if (objfile->deprecated_sym_stab_info != NULL)
|
||
{
|
||
xfree (objfile->deprecated_sym_stab_info);
|
||
}
|
||
|
||
dwarf2_free_objfile (objfile);
|
||
}
|
||
|
||
/* ELF specific initialization routine for reading symbols.
|
||
|
||
It is passed a pointer to a struct sym_fns which contains, among other
|
||
things, the BFD for the file whose symbols are being read, and a slot for
|
||
a pointer to "private data" which we can fill with goodies.
|
||
|
||
For now at least, we have nothing in particular to do, so this function is
|
||
just a stub. */
|
||
|
||
static void
|
||
elf_symfile_init (struct objfile *objfile)
|
||
{
|
||
/* ELF objects may be reordered, so set OBJF_REORDERED. If we
|
||
find this causes a significant slowdown in gdb then we could
|
||
set it in the debug symbol readers only when necessary. */
|
||
objfile->flags |= OBJF_REORDERED;
|
||
}
|
||
|
||
/* When handling an ELF file that contains Sun STABS debug info,
|
||
some of the debug info is relative to the particular chunk of the
|
||
section that was generated in its individual .o file. E.g.
|
||
offsets to static variables are relative to the start of the data
|
||
segment *for that module before linking*. This information is
|
||
painfully squirreled away in the ELF symbol table as local symbols
|
||
with wierd names. Go get 'em when needed. */
|
||
|
||
void
|
||
elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst)
|
||
{
|
||
const char *filename = pst->filename;
|
||
struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
|
||
struct stab_section_info *maybe = dbx->stab_section_info;
|
||
struct stab_section_info *questionable = 0;
|
||
int i;
|
||
char *p;
|
||
|
||
/* The ELF symbol info doesn't include path names, so strip the path
|
||
(if any) from the psymtab filename. */
|
||
while (0 != (p = strchr (filename, '/')))
|
||
filename = p + 1;
|
||
|
||
/* FIXME: This linear search could speed up significantly
|
||
if it was chained in the right order to match how we search it,
|
||
and if we unchained when we found a match. */
|
||
for (; maybe; maybe = maybe->next)
|
||
{
|
||
if (filename[0] == maybe->filename[0]
|
||
&& strcmp (filename, maybe->filename) == 0)
|
||
{
|
||
/* We found a match. But there might be several source files
|
||
(from different directories) with the same name. */
|
||
if (0 == maybe->found)
|
||
break;
|
||
questionable = maybe; /* Might use it later. */
|
||
}
|
||
}
|
||
|
||
if (maybe == 0 && questionable != 0)
|
||
{
|
||
complaint (&symfile_complaints,
|
||
_("elf/stab section information questionable for %s"),
|
||
filename);
|
||
maybe = questionable;
|
||
}
|
||
|
||
if (maybe)
|
||
{
|
||
/* Found it! Allocate a new psymtab struct, and fill it in. */
|
||
maybe->found++;
|
||
pst->section_offsets = (struct section_offsets *)
|
||
obstack_alloc (&objfile->objfile_obstack,
|
||
SIZEOF_N_SECTION_OFFSETS (objfile->num_sections));
|
||
for (i = 0; i < maybe->num_sections; i++)
|
||
(pst->section_offsets)->offsets[i] = maybe->sections[i];
|
||
return;
|
||
}
|
||
|
||
/* We were unable to find any offsets for this file. Complain. */
|
||
if (dbx->stab_section_info) /* If there *is* any info, */
|
||
complaint (&symfile_complaints,
|
||
_("elf/stab section information missing for %s"), filename);
|
||
}
|
||
|
||
/* Register that we are able to handle ELF object file formats. */
|
||
|
||
static const struct sym_fns elf_sym_fns =
|
||
{
|
||
bfd_target_elf_flavour,
|
||
elf_new_init, /* init anything gbl to entire symtab */
|
||
elf_symfile_init, /* read initial info, setup for sym_read() */
|
||
elf_symfile_read, /* read a symbol file into symtab */
|
||
elf_symfile_finish, /* finished with file, cleanup */
|
||
default_symfile_offsets, /* Translate ext. to int. relocation */
|
||
elf_symfile_segments, /* Get segment information from a file. */
|
||
NULL,
|
||
default_symfile_relocate, /* Relocate a debug section. */
|
||
&psym_functions
|
||
};
|
||
|
||
/* The same as elf_sym_fns, but not registered and uses the
|
||
DWARF-specific GNU index rather than psymtab. */
|
||
static const struct sym_fns elf_sym_fns_gdb_index =
|
||
{
|
||
bfd_target_elf_flavour,
|
||
elf_new_init, /* init anything gbl to entire symab */
|
||
elf_symfile_init, /* read initial info, setup for sym_red() */
|
||
elf_symfile_read, /* read a symbol file into symtab */
|
||
elf_symfile_finish, /* finished with file, cleanup */
|
||
default_symfile_offsets, /* Translate ext. to int. relocatin */
|
||
elf_symfile_segments, /* Get segment information from a file. */
|
||
NULL,
|
||
default_symfile_relocate, /* Relocate a debug section. */
|
||
&dwarf2_gdb_index_functions
|
||
};
|
||
|
||
void
|
||
_initialize_elfread (void)
|
||
{
|
||
add_symtab_fns (&elf_sym_fns);
|
||
}
|