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7b6c814ed7
logical location.
1764 lines
55 KiB
C
1764 lines
55 KiB
C
/* Read ELF (Executable and Linking Format) object files for GDB.
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Copyright (C) 1991-2013 Free Software Foundation, Inc.
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Written by Fred Fish at Cygnus Support.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it 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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This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "bfd.h"
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#include "gdb_string.h"
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#include "elf-bfd.h"
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#include "elf/common.h"
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#include "elf/internal.h"
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#include "elf/mips.h"
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#include "symtab.h"
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#include "symfile.h"
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#include "objfiles.h"
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#include "buildsym.h"
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#include "stabsread.h"
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#include "gdb-stabs.h"
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#include "complaints.h"
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#include "demangle.h"
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#include "psympriv.h"
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#include "filenames.h"
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#include "probe.h"
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#include "arch-utils.h"
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#include "gdbtypes.h"
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#include "value.h"
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#include "infcall.h"
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#include "gdbthread.h"
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#include "regcache.h"
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#include "bcache.h"
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#include "gdb_bfd.h"
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extern void _initialize_elfread (void);
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/* Forward declarations. */
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static const struct sym_fns elf_sym_fns_gdb_index;
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static const struct sym_fns elf_sym_fns_lazy_psyms;
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/* The struct elfinfo is available only during ELF symbol table and
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psymtab reading. It is destroyed at the completion of psymtab-reading.
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It's local to elf_symfile_read. */
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struct elfinfo
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{
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asection *stabsect; /* Section pointer for .stab section */
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asection *stabindexsect; /* Section pointer for .stab.index section */
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asection *mdebugsect; /* Section pointer for .mdebug section */
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};
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/* Per-objfile data for probe info. */
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static const struct objfile_data *probe_key = NULL;
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static void free_elfinfo (void *);
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/* Minimal symbols located at the GOT entries for .plt - that is the real
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pointer where the given entry will jump to. It gets updated by the real
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function address during lazy ld.so resolving in the inferior. These
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minimal symbols are indexed for <tab>-completion. */
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#define SYMBOL_GOT_PLT_SUFFIX "@got.plt"
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/* Locate the segments in ABFD. */
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static struct symfile_segment_data *
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elf_symfile_segments (bfd *abfd)
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{
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Elf_Internal_Phdr *phdrs, **segments;
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long phdrs_size;
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int num_phdrs, num_segments, num_sections, i;
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asection *sect;
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struct symfile_segment_data *data;
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phdrs_size = bfd_get_elf_phdr_upper_bound (abfd);
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if (phdrs_size == -1)
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return NULL;
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phdrs = alloca (phdrs_size);
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num_phdrs = bfd_get_elf_phdrs (abfd, phdrs);
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if (num_phdrs == -1)
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return NULL;
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num_segments = 0;
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segments = alloca (sizeof (Elf_Internal_Phdr *) * num_phdrs);
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for (i = 0; i < num_phdrs; i++)
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if (phdrs[i].p_type == PT_LOAD)
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segments[num_segments++] = &phdrs[i];
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if (num_segments == 0)
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return NULL;
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data = XZALLOC (struct symfile_segment_data);
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data->num_segments = num_segments;
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data->segment_bases = XCALLOC (num_segments, CORE_ADDR);
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data->segment_sizes = XCALLOC (num_segments, CORE_ADDR);
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for (i = 0; i < num_segments; i++)
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{
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data->segment_bases[i] = segments[i]->p_vaddr;
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data->segment_sizes[i] = segments[i]->p_memsz;
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}
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num_sections = bfd_count_sections (abfd);
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data->segment_info = XCALLOC (num_sections, int);
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for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next)
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{
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int j;
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CORE_ADDR vma;
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if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
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continue;
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vma = bfd_get_section_vma (abfd, sect);
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for (j = 0; j < num_segments; j++)
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if (segments[j]->p_memsz > 0
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&& vma >= segments[j]->p_vaddr
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&& (vma - segments[j]->p_vaddr) < segments[j]->p_memsz)
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{
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data->segment_info[i] = j + 1;
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break;
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}
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/* We should have found a segment for every non-empty section.
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If we haven't, we will not relocate this section by any
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offsets we apply to the segments. As an exception, do not
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warn about SHT_NOBITS sections; in normal ELF execution
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environments, SHT_NOBITS means zero-initialized and belongs
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in a segment, but in no-OS environments some tools (e.g. ARM
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RealView) use SHT_NOBITS for uninitialized data. Since it is
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uninitialized, it doesn't need a program header. Such
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binaries are not relocatable. */
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if (bfd_get_section_size (sect) > 0 && j == num_segments
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&& (bfd_get_section_flags (abfd, sect) & SEC_LOAD) != 0)
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warning (_("Loadable section \"%s\" outside of ELF segments"),
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bfd_section_name (abfd, sect));
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}
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return data;
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}
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/* We are called once per section from elf_symfile_read. We
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need to examine each section we are passed, check to see
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if it is something we are interested in processing, and
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if so, stash away some access information for the section.
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For now we recognize the dwarf debug information sections and
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line number sections from matching their section names. The
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ELF definition is no real help here since it has no direct
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knowledge of DWARF (by design, so any debugging format can be
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used).
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We also recognize the ".stab" sections used by the Sun compilers
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released with Solaris 2.
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FIXME: The section names should not be hardwired strings (what
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should they be? I don't think most object file formats have enough
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section flags to specify what kind of debug section it is.
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-kingdon). */
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static void
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elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip)
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{
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struct elfinfo *ei;
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ei = (struct elfinfo *) eip;
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if (strcmp (sectp->name, ".stab") == 0)
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{
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ei->stabsect = sectp;
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}
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else if (strcmp (sectp->name, ".stab.index") == 0)
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{
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ei->stabindexsect = sectp;
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}
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else if (strcmp (sectp->name, ".mdebug") == 0)
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{
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ei->mdebugsect = sectp;
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}
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}
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static struct minimal_symbol *
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record_minimal_symbol (const char *name, int name_len, int copy_name,
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CORE_ADDR address,
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enum minimal_symbol_type ms_type,
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asection *bfd_section, struct objfile *objfile)
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{
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struct gdbarch *gdbarch = get_objfile_arch (objfile);
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if (ms_type == mst_text || ms_type == mst_file_text
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|| ms_type == mst_text_gnu_ifunc)
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address = gdbarch_addr_bits_remove (gdbarch, address);
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return prim_record_minimal_symbol_full (name, name_len, copy_name, address,
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ms_type, bfd_section->index,
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bfd_section, objfile);
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}
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/* Read the symbol table of an ELF file.
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Given an objfile, a symbol table, and a flag indicating whether the
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symbol table contains regular, dynamic, or synthetic symbols, add all
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the global function and data symbols to the minimal symbol table.
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In stabs-in-ELF, as implemented by Sun, there are some local symbols
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defined in the ELF symbol table, which can be used to locate
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the beginnings of sections from each ".o" file that was linked to
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form the executable objfile. We gather any such info and record it
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in data structures hung off the objfile's private data. */
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#define ST_REGULAR 0
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#define ST_DYNAMIC 1
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#define ST_SYNTHETIC 2
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static void
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elf_symtab_read (struct objfile *objfile, int type,
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long number_of_symbols, asymbol **symbol_table,
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int copy_names)
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{
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struct gdbarch *gdbarch = get_objfile_arch (objfile);
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asymbol *sym;
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long i;
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CORE_ADDR symaddr;
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CORE_ADDR offset;
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enum minimal_symbol_type ms_type;
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/* If sectinfo is nonNULL, it contains section info that should end up
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filed in the objfile. */
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struct stab_section_info *sectinfo = NULL;
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/* If filesym is nonzero, it points to a file symbol, but we haven't
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seen any section info for it yet. */
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asymbol *filesym = 0;
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/* Name of filesym. This is either a constant string or is saved on
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the objfile's filename cache. */
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const char *filesymname = "";
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struct dbx_symfile_info *dbx = DBX_SYMFILE_INFO (objfile);
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int stripped = (bfd_get_symcount (objfile->obfd) == 0);
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for (i = 0; i < number_of_symbols; i++)
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{
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sym = symbol_table[i];
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if (sym->name == NULL || *sym->name == '\0')
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{
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/* Skip names that don't exist (shouldn't happen), or names
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that are null strings (may happen). */
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continue;
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}
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/* Skip "special" symbols, e.g. ARM mapping symbols. These are
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symbols which do not correspond to objects in the symbol table,
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but have some other target-specific meaning. */
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if (bfd_is_target_special_symbol (objfile->obfd, sym))
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{
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if (gdbarch_record_special_symbol_p (gdbarch))
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gdbarch_record_special_symbol (gdbarch, objfile, sym);
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continue;
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}
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offset = ANOFFSET (objfile->section_offsets, sym->section->index);
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if (type == ST_DYNAMIC
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&& sym->section == bfd_und_section_ptr
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&& (sym->flags & BSF_FUNCTION))
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{
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struct minimal_symbol *msym;
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bfd *abfd = objfile->obfd;
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asection *sect;
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/* Symbol is a reference to a function defined in
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a shared library.
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If its value is non zero then it is usually the address
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of the corresponding entry in the procedure linkage table,
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plus the desired section offset.
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If its value is zero then the dynamic linker has to resolve
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the symbol. We are unable to find any meaningful address
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for this symbol in the executable file, so we skip it. */
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symaddr = sym->value;
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if (symaddr == 0)
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continue;
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/* sym->section is the undefined section. However, we want to
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record the section where the PLT stub resides with the
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minimal symbol. Search the section table for the one that
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covers the stub's address. */
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for (sect = abfd->sections; sect != NULL; sect = sect->next)
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{
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if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
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continue;
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if (symaddr >= bfd_get_section_vma (abfd, sect)
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&& symaddr < bfd_get_section_vma (abfd, sect)
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+ bfd_get_section_size (sect))
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break;
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}
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if (!sect)
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continue;
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/* On ia64-hpux, we have discovered that the system linker
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adds undefined symbols with nonzero addresses that cannot
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be right (their address points inside the code of another
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function in the .text section). This creates problems
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when trying to determine which symbol corresponds to
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a given address.
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We try to detect those buggy symbols by checking which
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section we think they correspond to. Normally, PLT symbols
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are stored inside their own section, and the typical name
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for that section is ".plt". So, if there is a ".plt"
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section, and yet the section name of our symbol does not
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start with ".plt", we ignore that symbol. */
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if (strncmp (sect->name, ".plt", 4) != 0
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&& bfd_get_section_by_name (abfd, ".plt") != NULL)
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continue;
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symaddr += ANOFFSET (objfile->section_offsets, sect->index);
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msym = record_minimal_symbol
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(sym->name, strlen (sym->name), copy_names,
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symaddr, mst_solib_trampoline, sect, objfile);
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if (msym != NULL)
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msym->filename = filesymname;
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continue;
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}
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/* If it is a nonstripped executable, do not enter dynamic
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symbols, as the dynamic symbol table is usually a subset
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of the main symbol table. */
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if (type == ST_DYNAMIC && !stripped)
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continue;
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if (sym->flags & BSF_FILE)
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{
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/* STT_FILE debugging symbol that helps stabs-in-elf debugging.
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Chain any old one onto the objfile; remember new sym. */
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if (sectinfo != NULL)
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{
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sectinfo->next = dbx->stab_section_info;
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dbx->stab_section_info = sectinfo;
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sectinfo = NULL;
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}
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filesym = sym;
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filesymname = bcache (filesym->name, strlen (filesym->name) + 1,
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objfile->per_bfd->filename_cache);
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}
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else if (sym->flags & BSF_SECTION_SYM)
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continue;
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else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
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{
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struct minimal_symbol *msym;
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/* Select global/local/weak symbols. Note that bfd puts abs
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symbols in their own section, so all symbols we are
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interested in will have a section. */
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/* Bfd symbols are section relative. */
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symaddr = sym->value + sym->section->vma;
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/* Relocate all non-absolute and non-TLS symbols by the
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section offset. */
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if (sym->section != bfd_abs_section_ptr
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&& !(sym->section->flags & SEC_THREAD_LOCAL))
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{
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symaddr += offset;
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}
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/* For non-absolute symbols, use the type of the section
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they are relative to, to intuit text/data. Bfd provides
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no way of figuring this out for absolute symbols. */
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if (sym->section == bfd_abs_section_ptr)
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{
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/* This is a hack to get the minimal symbol type
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right for Irix 5, which has absolute addresses
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with special section indices for dynamic symbols.
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NOTE: uweigand-20071112: Synthetic symbols do not
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have an ELF-private part, so do not touch those. */
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unsigned int shndx = type == ST_SYNTHETIC ? 0 :
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((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
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switch (shndx)
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{
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case SHN_MIPS_TEXT:
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ms_type = mst_text;
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break;
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case SHN_MIPS_DATA:
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ms_type = mst_data;
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break;
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case SHN_MIPS_ACOMMON:
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ms_type = mst_bss;
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break;
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default:
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ms_type = mst_abs;
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}
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/* If it is an Irix dynamic symbol, skip section name
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symbols, relocate all others by section offset. */
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if (ms_type != mst_abs)
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{
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if (sym->name[0] == '.')
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continue;
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symaddr += offset;
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}
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}
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else if (sym->section->flags & SEC_CODE)
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{
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if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
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{
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if (sym->flags & BSF_GNU_INDIRECT_FUNCTION)
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ms_type = mst_text_gnu_ifunc;
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else
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ms_type = mst_text;
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}
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/* The BSF_SYNTHETIC check is there to omit ppc64 function
|
||
descriptors mistaken for static functions starting with 'L'.
|
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*/
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else if ((sym->name[0] == '.' && sym->name[1] == 'L'
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&& (sym->flags & BSF_SYNTHETIC) == 0)
|
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|| ((sym->flags & BSF_LOCAL)
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&& sym->name[0] == '$'
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&& 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
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||
I encourage people to fix this in the assembler
|
||
instead of adding checks here). */
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||
continue;
|
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else
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{
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||
ms_type = mst_file_text;
|
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}
|
||
}
|
||
else if (sym->section->flags & SEC_ALLOC)
|
||
{
|
||
if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
|
||
{
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||
if (sym->section->flags & SEC_LOAD)
|
||
{
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||
ms_type = mst_data;
|
||
}
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||
else
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{
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||
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;
|
||
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if (strcmp ("Bbss.bss", sym->name) == 0)
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special_local_sect = SECT_OFF_BSS (objfile);
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else if (strcmp ("Ddata.data", sym->name) == 0)
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special_local_sect = SECT_OFF_DATA (objfile);
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||
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_ptr)
|
||
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)
|
||
{
|
||
/* NOTE: uweigand-20071112: A synthetic symbol does not have an
|
||
ELF-private part. */
|
||
if (type != ST_SYNTHETIC)
|
||
{
|
||
/* Pass symbol size field in via BFD. FIXME!!! */
|
||
elf_symbol_type *elf_sym = (elf_symbol_type *) sym;
|
||
SET_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)
|
||
{
|
||
SET_MSYMBOL_SIZE (mtramp, MSYMBOL_SIZE (msym));
|
||
mtramp->created_by_gdb = 1;
|
||
mtramp->filename = filesymname;
|
||
gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Build minimal symbols named `function@got.plt' (see SYMBOL_GOT_PLT_SUFFIX)
|
||
for later look ups of which function to call when user requests
|
||
a STT_GNU_IFUNC function. As the STT_GNU_IFUNC type is found at the target
|
||
library defining `function' we cannot yet know while reading OBJFILE which
|
||
of the SYMBOL_GOT_PLT_SUFFIX entries will be needed and later
|
||
DYN_SYMBOL_TABLE is no longer easily available for OBJFILE. */
|
||
|
||
static void
|
||
elf_rel_plt_read (struct objfile *objfile, asymbol **dyn_symbol_table)
|
||
{
|
||
bfd *obfd = objfile->obfd;
|
||
const struct elf_backend_data *bed = get_elf_backend_data (obfd);
|
||
asection *plt, *relplt, *got_plt;
|
||
int plt_elf_idx;
|
||
bfd_size_type reloc_count, reloc;
|
||
char *string_buffer = NULL;
|
||
size_t string_buffer_size = 0;
|
||
struct cleanup *back_to;
|
||
struct gdbarch *gdbarch = objfile->gdbarch;
|
||
struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
|
||
size_t ptr_size = TYPE_LENGTH (ptr_type);
|
||
|
||
if (objfile->separate_debug_objfile_backlink)
|
||
return;
|
||
|
||
plt = bfd_get_section_by_name (obfd, ".plt");
|
||
if (plt == NULL)
|
||
return;
|
||
plt_elf_idx = elf_section_data (plt)->this_idx;
|
||
|
||
got_plt = bfd_get_section_by_name (obfd, ".got.plt");
|
||
if (got_plt == NULL)
|
||
return;
|
||
|
||
/* This search algorithm is from _bfd_elf_canonicalize_dynamic_reloc. */
|
||
for (relplt = obfd->sections; relplt != NULL; relplt = relplt->next)
|
||
if (elf_section_data (relplt)->this_hdr.sh_info == plt_elf_idx
|
||
&& (elf_section_data (relplt)->this_hdr.sh_type == SHT_REL
|
||
|| elf_section_data (relplt)->this_hdr.sh_type == SHT_RELA))
|
||
break;
|
||
if (relplt == NULL)
|
||
return;
|
||
|
||
if (! bed->s->slurp_reloc_table (obfd, relplt, dyn_symbol_table, TRUE))
|
||
return;
|
||
|
||
back_to = make_cleanup (free_current_contents, &string_buffer);
|
||
|
||
reloc_count = relplt->size / elf_section_data (relplt)->this_hdr.sh_entsize;
|
||
for (reloc = 0; reloc < reloc_count; reloc++)
|
||
{
|
||
const char *name;
|
||
struct minimal_symbol *msym;
|
||
CORE_ADDR address;
|
||
const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX);
|
||
size_t name_len;
|
||
|
||
name = bfd_asymbol_name (*relplt->relocation[reloc].sym_ptr_ptr);
|
||
name_len = strlen (name);
|
||
address = relplt->relocation[reloc].address;
|
||
|
||
/* Does the pointer reside in the .got.plt section? */
|
||
if (!(bfd_get_section_vma (obfd, got_plt) <= address
|
||
&& address < bfd_get_section_vma (obfd, got_plt)
|
||
+ bfd_get_section_size (got_plt)))
|
||
continue;
|
||
|
||
/* We cannot check if NAME is a reference to mst_text_gnu_ifunc as in
|
||
OBJFILE the symbol is undefined and the objfile having NAME defined
|
||
may not yet have been loaded. */
|
||
|
||
if (string_buffer_size < name_len + got_suffix_len + 1)
|
||
{
|
||
string_buffer_size = 2 * (name_len + got_suffix_len);
|
||
string_buffer = xrealloc (string_buffer, string_buffer_size);
|
||
}
|
||
memcpy (string_buffer, name, name_len);
|
||
memcpy (&string_buffer[name_len], SYMBOL_GOT_PLT_SUFFIX,
|
||
got_suffix_len + 1);
|
||
|
||
msym = record_minimal_symbol (string_buffer, name_len + got_suffix_len,
|
||
1, address, mst_slot_got_plt, got_plt,
|
||
objfile);
|
||
if (msym)
|
||
SET_MSYMBOL_SIZE (msym, ptr_size);
|
||
}
|
||
|
||
do_cleanups (back_to);
|
||
}
|
||
|
||
/* The data pointer is htab_t for gnu_ifunc_record_cache_unchecked. */
|
||
|
||
static const struct objfile_data *elf_objfile_gnu_ifunc_cache_data;
|
||
|
||
/* Map function names to CORE_ADDR in elf_objfile_gnu_ifunc_cache_data. */
|
||
|
||
struct elf_gnu_ifunc_cache
|
||
{
|
||
/* This is always a function entry address, not a function descriptor. */
|
||
CORE_ADDR addr;
|
||
|
||
char name[1];
|
||
};
|
||
|
||
/* htab_hash for elf_objfile_gnu_ifunc_cache_data. */
|
||
|
||
static hashval_t
|
||
elf_gnu_ifunc_cache_hash (const void *a_voidp)
|
||
{
|
||
const struct elf_gnu_ifunc_cache *a = a_voidp;
|
||
|
||
return htab_hash_string (a->name);
|
||
}
|
||
|
||
/* htab_eq for elf_objfile_gnu_ifunc_cache_data. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_cache_eq (const void *a_voidp, const void *b_voidp)
|
||
{
|
||
const struct elf_gnu_ifunc_cache *a = a_voidp;
|
||
const struct elf_gnu_ifunc_cache *b = b_voidp;
|
||
|
||
return strcmp (a->name, b->name) == 0;
|
||
}
|
||
|
||
/* Record the target function address of a STT_GNU_IFUNC function NAME is the
|
||
function entry address ADDR. Return 1 if NAME and ADDR are considered as
|
||
valid and therefore they were successfully recorded, return 0 otherwise.
|
||
|
||
Function does not expect a duplicate entry. Use
|
||
elf_gnu_ifunc_resolve_by_cache first to check if the entry for NAME already
|
||
exists. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_record_cache (const char *name, CORE_ADDR addr)
|
||
{
|
||
struct minimal_symbol *msym;
|
||
asection *sect;
|
||
struct objfile *objfile;
|
||
htab_t htab;
|
||
struct elf_gnu_ifunc_cache entry_local, *entry_p;
|
||
void **slot;
|
||
|
||
msym = lookup_minimal_symbol_by_pc (addr);
|
||
if (msym == NULL)
|
||
return 0;
|
||
if (SYMBOL_VALUE_ADDRESS (msym) != addr)
|
||
return 0;
|
||
/* minimal symbols have always SYMBOL_OBJ_SECTION non-NULL. */
|
||
sect = SYMBOL_OBJ_SECTION (msym)->the_bfd_section;
|
||
objfile = SYMBOL_OBJ_SECTION (msym)->objfile;
|
||
|
||
/* If .plt jumps back to .plt the symbol is still deferred for later
|
||
resolution and it has no use for GDB. Besides ".text" this symbol can
|
||
reside also in ".opd" for ppc64 function descriptor. */
|
||
if (strcmp (bfd_get_section_name (objfile->obfd, sect), ".plt") == 0)
|
||
return 0;
|
||
|
||
htab = objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data);
|
||
if (htab == NULL)
|
||
{
|
||
htab = htab_create_alloc_ex (1, elf_gnu_ifunc_cache_hash,
|
||
elf_gnu_ifunc_cache_eq,
|
||
NULL, &objfile->objfile_obstack,
|
||
hashtab_obstack_allocate,
|
||
dummy_obstack_deallocate);
|
||
set_objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data, htab);
|
||
}
|
||
|
||
entry_local.addr = addr;
|
||
obstack_grow (&objfile->objfile_obstack, &entry_local,
|
||
offsetof (struct elf_gnu_ifunc_cache, name));
|
||
obstack_grow_str0 (&objfile->objfile_obstack, name);
|
||
entry_p = obstack_finish (&objfile->objfile_obstack);
|
||
|
||
slot = htab_find_slot (htab, entry_p, INSERT);
|
||
if (*slot != NULL)
|
||
{
|
||
struct elf_gnu_ifunc_cache *entry_found_p = *slot;
|
||
struct gdbarch *gdbarch = objfile->gdbarch;
|
||
|
||
if (entry_found_p->addr != addr)
|
||
{
|
||
/* This case indicates buggy inferior program, the resolved address
|
||
should never change. */
|
||
|
||
warning (_("gnu-indirect-function \"%s\" has changed its resolved "
|
||
"function_address from %s to %s"),
|
||
name, paddress (gdbarch, entry_found_p->addr),
|
||
paddress (gdbarch, addr));
|
||
}
|
||
|
||
/* New ENTRY_P is here leaked/duplicate in the OBJFILE obstack. */
|
||
}
|
||
*slot = entry_p;
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Try to find the target resolved function entry address of a STT_GNU_IFUNC
|
||
function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
|
||
is not NULL) and the function returns 1. It returns 0 otherwise.
|
||
|
||
Only the elf_objfile_gnu_ifunc_cache_data hash table is searched by this
|
||
function. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_resolve_by_cache (const char *name, CORE_ADDR *addr_p)
|
||
{
|
||
struct objfile *objfile;
|
||
|
||
ALL_PSPACE_OBJFILES (current_program_space, objfile)
|
||
{
|
||
htab_t htab;
|
||
struct elf_gnu_ifunc_cache *entry_p;
|
||
void **slot;
|
||
|
||
htab = objfile_data (objfile, elf_objfile_gnu_ifunc_cache_data);
|
||
if (htab == NULL)
|
||
continue;
|
||
|
||
entry_p = alloca (sizeof (*entry_p) + strlen (name));
|
||
strcpy (entry_p->name, name);
|
||
|
||
slot = htab_find_slot (htab, entry_p, NO_INSERT);
|
||
if (slot == NULL)
|
||
continue;
|
||
entry_p = *slot;
|
||
gdb_assert (entry_p != NULL);
|
||
|
||
if (addr_p)
|
||
*addr_p = entry_p->addr;
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Try to find the target resolved function entry address of a STT_GNU_IFUNC
|
||
function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
|
||
is not NULL) and the function returns 1. It returns 0 otherwise.
|
||
|
||
Only the SYMBOL_GOT_PLT_SUFFIX locations are searched by this function.
|
||
elf_gnu_ifunc_resolve_by_cache must have been already called for NAME to
|
||
prevent cache entries duplicates. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_resolve_by_got (const char *name, CORE_ADDR *addr_p)
|
||
{
|
||
char *name_got_plt;
|
||
struct objfile *objfile;
|
||
const size_t got_suffix_len = strlen (SYMBOL_GOT_PLT_SUFFIX);
|
||
|
||
name_got_plt = alloca (strlen (name) + got_suffix_len + 1);
|
||
sprintf (name_got_plt, "%s" SYMBOL_GOT_PLT_SUFFIX, name);
|
||
|
||
ALL_PSPACE_OBJFILES (current_program_space, objfile)
|
||
{
|
||
bfd *obfd = objfile->obfd;
|
||
struct gdbarch *gdbarch = objfile->gdbarch;
|
||
struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
|
||
size_t ptr_size = TYPE_LENGTH (ptr_type);
|
||
CORE_ADDR pointer_address, addr;
|
||
asection *plt;
|
||
gdb_byte *buf = alloca (ptr_size);
|
||
struct minimal_symbol *msym;
|
||
|
||
msym = lookup_minimal_symbol (name_got_plt, NULL, objfile);
|
||
if (msym == NULL)
|
||
continue;
|
||
if (MSYMBOL_TYPE (msym) != mst_slot_got_plt)
|
||
continue;
|
||
pointer_address = SYMBOL_VALUE_ADDRESS (msym);
|
||
|
||
plt = bfd_get_section_by_name (obfd, ".plt");
|
||
if (plt == NULL)
|
||
continue;
|
||
|
||
if (MSYMBOL_SIZE (msym) != ptr_size)
|
||
continue;
|
||
if (target_read_memory (pointer_address, buf, ptr_size) != 0)
|
||
continue;
|
||
addr = extract_typed_address (buf, ptr_type);
|
||
addr = gdbarch_convert_from_func_ptr_addr (gdbarch, addr,
|
||
¤t_target);
|
||
|
||
if (addr_p)
|
||
*addr_p = addr;
|
||
if (elf_gnu_ifunc_record_cache (name, addr))
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Try to find the target resolved function entry address of a STT_GNU_IFUNC
|
||
function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
|
||
is not NULL) and the function returns 1. It returns 0 otherwise.
|
||
|
||
Both the elf_objfile_gnu_ifunc_cache_data hash table and
|
||
SYMBOL_GOT_PLT_SUFFIX locations are searched by this function. */
|
||
|
||
static int
|
||
elf_gnu_ifunc_resolve_name (const char *name, CORE_ADDR *addr_p)
|
||
{
|
||
if (elf_gnu_ifunc_resolve_by_cache (name, addr_p))
|
||
return 1;
|
||
|
||
if (elf_gnu_ifunc_resolve_by_got (name, addr_p))
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Call STT_GNU_IFUNC - a function returning addresss of a real function to
|
||
call. PC is theSTT_GNU_IFUNC resolving function entry. The value returned
|
||
is the entry point of the resolved STT_GNU_IFUNC target function to call.
|
||
*/
|
||
|
||
static CORE_ADDR
|
||
elf_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
|
||
{
|
||
const char *name_at_pc;
|
||
CORE_ADDR start_at_pc, address;
|
||
struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func;
|
||
struct value *function, *address_val;
|
||
|
||
/* Try first any non-intrusive methods without an inferior call. */
|
||
|
||
if (find_pc_partial_function (pc, &name_at_pc, &start_at_pc, NULL)
|
||
&& start_at_pc == pc)
|
||
{
|
||
if (elf_gnu_ifunc_resolve_name (name_at_pc, &address))
|
||
return address;
|
||
}
|
||
else
|
||
name_at_pc = NULL;
|
||
|
||
function = allocate_value (func_func_type);
|
||
set_value_address (function, pc);
|
||
|
||
/* STT_GNU_IFUNC resolver functions have no parameters. FUNCTION is the
|
||
function entry address. ADDRESS may be a function descriptor. */
|
||
|
||
address_val = call_function_by_hand (function, 0, NULL);
|
||
address = value_as_address (address_val);
|
||
address = gdbarch_convert_from_func_ptr_addr (gdbarch, address,
|
||
¤t_target);
|
||
|
||
if (name_at_pc)
|
||
elf_gnu_ifunc_record_cache (name_at_pc, address);
|
||
|
||
return address;
|
||
}
|
||
|
||
/* Handle inferior hit of bp_gnu_ifunc_resolver, see its definition. */
|
||
|
||
static void
|
||
elf_gnu_ifunc_resolver_stop (struct breakpoint *b)
|
||
{
|
||
struct breakpoint *b_return;
|
||
struct frame_info *prev_frame = get_prev_frame (get_current_frame ());
|
||
struct frame_id prev_frame_id = get_stack_frame_id (prev_frame);
|
||
CORE_ADDR prev_pc = get_frame_pc (prev_frame);
|
||
int thread_id = pid_to_thread_id (inferior_ptid);
|
||
|
||
gdb_assert (b->type == bp_gnu_ifunc_resolver);
|
||
|
||
for (b_return = b->related_breakpoint; b_return != b;
|
||
b_return = b_return->related_breakpoint)
|
||
{
|
||
gdb_assert (b_return->type == bp_gnu_ifunc_resolver_return);
|
||
gdb_assert (b_return->loc != NULL && b_return->loc->next == NULL);
|
||
gdb_assert (frame_id_p (b_return->frame_id));
|
||
|
||
if (b_return->thread == thread_id
|
||
&& b_return->loc->requested_address == prev_pc
|
||
&& frame_id_eq (b_return->frame_id, prev_frame_id))
|
||
break;
|
||
}
|
||
|
||
if (b_return == b)
|
||
{
|
||
struct symtab_and_line sal;
|
||
|
||
/* No need to call find_pc_line for symbols resolving as this is only
|
||
a helper breakpointer never shown to the user. */
|
||
|
||
init_sal (&sal);
|
||
sal.pspace = current_inferior ()->pspace;
|
||
sal.pc = prev_pc;
|
||
sal.section = find_pc_overlay (sal.pc);
|
||
sal.explicit_pc = 1;
|
||
b_return = set_momentary_breakpoint (get_frame_arch (prev_frame), sal,
|
||
prev_frame_id,
|
||
bp_gnu_ifunc_resolver_return);
|
||
|
||
/* set_momentary_breakpoint invalidates PREV_FRAME. */
|
||
prev_frame = NULL;
|
||
|
||
/* Add new b_return to the ring list b->related_breakpoint. */
|
||
gdb_assert (b_return->related_breakpoint == b_return);
|
||
b_return->related_breakpoint = b->related_breakpoint;
|
||
b->related_breakpoint = b_return;
|
||
}
|
||
}
|
||
|
||
/* Handle inferior hit of bp_gnu_ifunc_resolver_return, see its definition. */
|
||
|
||
static void
|
||
elf_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
|
||
{
|
||
struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
|
||
struct type *func_func_type = builtin_type (gdbarch)->builtin_func_func;
|
||
struct type *value_type = TYPE_TARGET_TYPE (func_func_type);
|
||
struct regcache *regcache = get_thread_regcache (inferior_ptid);
|
||
struct value *func_func;
|
||
struct value *value;
|
||
CORE_ADDR resolved_address, resolved_pc;
|
||
struct symtab_and_line sal;
|
||
struct symtabs_and_lines sals, sals_end;
|
||
|
||
gdb_assert (b->type == bp_gnu_ifunc_resolver_return);
|
||
|
||
while (b->related_breakpoint != b)
|
||
{
|
||
struct breakpoint *b_next = b->related_breakpoint;
|
||
|
||
switch (b->type)
|
||
{
|
||
case bp_gnu_ifunc_resolver:
|
||
break;
|
||
case bp_gnu_ifunc_resolver_return:
|
||
delete_breakpoint (b);
|
||
break;
|
||
default:
|
||
internal_error (__FILE__, __LINE__,
|
||
_("handle_inferior_event: Invalid "
|
||
"gnu-indirect-function breakpoint type %d"),
|
||
(int) b->type);
|
||
}
|
||
b = b_next;
|
||
}
|
||
gdb_assert (b->type == bp_gnu_ifunc_resolver);
|
||
gdb_assert (b->loc->next == NULL);
|
||
|
||
func_func = allocate_value (func_func_type);
|
||
set_value_address (func_func, b->loc->related_address);
|
||
|
||
value = allocate_value (value_type);
|
||
gdbarch_return_value (gdbarch, func_func, value_type, regcache,
|
||
value_contents_raw (value), NULL);
|
||
resolved_address = value_as_address (value);
|
||
resolved_pc = gdbarch_convert_from_func_ptr_addr (gdbarch,
|
||
resolved_address,
|
||
¤t_target);
|
||
|
||
gdb_assert (current_program_space == b->pspace || b->pspace == NULL);
|
||
elf_gnu_ifunc_record_cache (b->addr_string, resolved_pc);
|
||
|
||
sal = find_pc_line (resolved_pc, 0);
|
||
sals.nelts = 1;
|
||
sals.sals = &sal;
|
||
sals_end.nelts = 0;
|
||
|
||
b->type = bp_breakpoint;
|
||
update_breakpoint_locations (b, sals, sals_end);
|
||
}
|
||
|
||
/* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
|
||
|
||
static const struct elf_build_id *
|
||
build_id_bfd_get (bfd *abfd)
|
||
{
|
||
if (!bfd_check_format (abfd, bfd_object)
|
||
|| bfd_get_flavour (abfd) != bfd_target_elf_flavour
|
||
|| elf_tdata (abfd)->build_id == NULL)
|
||
return NULL;
|
||
|
||
return elf_tdata (abfd)->build_id;
|
||
}
|
||
|
||
/* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */
|
||
|
||
static int
|
||
build_id_verify (const char *filename, const struct elf_build_id *check)
|
||
{
|
||
bfd *abfd;
|
||
const struct elf_build_id *found;
|
||
int retval = 0;
|
||
|
||
/* We expect to be silent on the non-existing files. */
|
||
abfd = gdb_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_unref (abfd);
|
||
|
||
return retval;
|
||
}
|
||
|
||
static char *
|
||
build_id_to_debug_filename (const struct elf_build_id *build_id)
|
||
{
|
||
char *link, *debugdir, *retval = NULL;
|
||
VEC (char_ptr) *debugdir_vec;
|
||
struct cleanup *back_to;
|
||
int ix;
|
||
|
||
/* 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_vec = dirnames_to_char_ptr_vec (debug_file_directory);
|
||
back_to = make_cleanup_free_char_ptr_vec (debugdir_vec);
|
||
|
||
for (ix = 0; VEC_iterate (char_ptr, debugdir_vec, ix, debugdir); ++ix)
|
||
{
|
||
size_t debugdir_len = strlen (debugdir);
|
||
const gdb_byte *data = build_id->data;
|
||
size_t size = build_id->size;
|
||
char *s;
|
||
|
||
memcpy (link, debugdir, debugdir_len);
|
||
s = &link[debugdir_len];
|
||
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;
|
||
}
|
||
|
||
do_cleanups (back_to);
|
||
return retval;
|
||
}
|
||
|
||
static char *
|
||
find_separate_debug_file_by_buildid (struct objfile *objfile)
|
||
{
|
||
const struct elf_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);
|
||
/* Prevent looping on a stripped .debug file. */
|
||
if (build_id_name != NULL
|
||
&& filename_cmp (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 *synth_abfd, *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;
|
||
struct dbx_symfile_info *dbx;
|
||
|
||
if (symtab_create_debug)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"Reading minimal symbols of objfile %s ...\n",
|
||
objfile->name);
|
||
}
|
||
|
||
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. */
|
||
dbx = XCNEW (struct dbx_symfile_info);
|
||
set_objfile_data (objfile, dbx_objfile_data_key, dbx);
|
||
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 of the objfile, 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);
|
||
|
||
elf_rel_plt_read (objfile, dyn_symbol_table);
|
||
}
|
||
|
||
/* Contrary to binutils --strip-debug/--only-keep-debug the strip command from
|
||
elfutils (eu-strip) moves even the .symtab section into the .debug file.
|
||
|
||
bfd_get_synthetic_symtab on ppc64 for each function descriptor ELF symbol
|
||
'name' creates a new BSF_SYNTHETIC ELF symbol '.name' with its code
|
||
address. But with eu-strip files bfd_get_synthetic_symtab would fail to
|
||
read the code address from .opd while it reads the .symtab section from
|
||
a separate debug info file as the .opd section is SHT_NOBITS there.
|
||
|
||
With SYNTH_ABFD the .opd section will be read from the original
|
||
backlinked binary where it is valid. */
|
||
|
||
if (objfile->separate_debug_objfile_backlink)
|
||
synth_abfd = objfile->separate_debug_objfile_backlink->obfd;
|
||
else
|
||
synth_abfd = abfd;
|
||
|
||
/* Add synthetic symbols - for instance, names for any PLT entries. */
|
||
|
||
synthcount = bfd_get_synthetic_symtab (synth_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 (symtab_create_debug)
|
||
fprintf_unfiltered (gdb_stdlog, "Done reading minimal symbols.\n");
|
||
|
||
if (dwarf2_has_info (objfile, NULL))
|
||
{
|
||
/* elf_sym_fns_gdb_index cannot handle simultaneous non-DWARF debug
|
||
information present in OBJFILE. If there is such debug info present
|
||
never use .gdb_index. */
|
||
|
||
if (!objfile_has_partial_symbols (objfile)
|
||
&& dwarf2_initialize_objfile (objfile))
|
||
objfile->sf = &elf_sym_fns_gdb_index;
|
||
else
|
||
{
|
||
/* It is ok to do this even if the stabs reader made some
|
||
partial symbols, because OBJF_PSYMTABS_READ has not been
|
||
set, and so our lazy reader function will still be called
|
||
when needed. */
|
||
objfile->sf = &elf_sym_fns_lazy_psyms;
|
||
}
|
||
}
|
||
/* 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'.
|
||
|
||
.gnu_debugdata is !objfile_has_partial_symbols because it contains only
|
||
.symtab, not .debug_* section. But if we already added .gnu_debugdata as
|
||
an objfile via find_separate_debug_file_in_section there was no separate
|
||
debug info available. Therefore do not attempt to search for another one,
|
||
objfile->separate_debug_objfile->separate_debug_objfile GDB guarantees to
|
||
be NULL and we would possibly violate it. */
|
||
|
||
else if (!objfile_has_partial_symbols (objfile)
|
||
&& objfile->separate_debug_objfile == NULL
|
||
&& objfile->separate_debug_objfile_backlink == NULL)
|
||
{
|
||
char *debugfile;
|
||
|
||
debugfile = find_separate_debug_file_by_buildid (objfile);
|
||
|
||
if (debugfile == NULL)
|
||
debugfile = find_separate_debug_file_by_debuglink (objfile);
|
||
|
||
if (debugfile)
|
||
{
|
||
struct cleanup *cleanup = make_cleanup (xfree, debugfile);
|
||
bfd *abfd = symfile_bfd_open (debugfile);
|
||
|
||
make_cleanup_bfd_unref (abfd);
|
||
symbol_file_add_separate (abfd, symfile_flags, objfile);
|
||
do_cleanups (cleanup);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Callback to lazily read psymtabs. */
|
||
|
||
static void
|
||
read_psyms (struct objfile *objfile)
|
||
{
|
||
if (dwarf2_has_info (objfile, NULL))
|
||
dwarf2_build_psymtabs (objfile);
|
||
}
|
||
|
||
/* This cleans up the objfile's dbx symfile info, 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 = DBX_SYMFILE_INFO (objfile);
|
||
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)
|
||
{
|
||
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 = DBX_SYMFILE_INFO (objfile);
|
||
struct stab_section_info *maybe = dbx->stab_section_info;
|
||
struct stab_section_info *questionable = 0;
|
||
int i;
|
||
|
||
/* The ELF symbol info doesn't include path names, so strip the path
|
||
(if any) from the psymtab filename. */
|
||
filename = lbasename (filename);
|
||
|
||
/* 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]
|
||
&& filename_cmp (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);
|
||
}
|
||
|
||
/* Implementation of `sym_get_probes', as documented in symfile.h. */
|
||
|
||
static VEC (probe_p) *
|
||
elf_get_probes (struct objfile *objfile)
|
||
{
|
||
VEC (probe_p) *probes_per_objfile;
|
||
|
||
/* Have we parsed this objfile's probes already? */
|
||
probes_per_objfile = objfile_data (objfile, probe_key);
|
||
|
||
if (!probes_per_objfile)
|
||
{
|
||
int ix;
|
||
const struct probe_ops *probe_ops;
|
||
|
||
/* Here we try to gather information about all types of probes from the
|
||
objfile. */
|
||
for (ix = 0; VEC_iterate (probe_ops_cp, all_probe_ops, ix, probe_ops);
|
||
ix++)
|
||
probe_ops->get_probes (&probes_per_objfile, objfile);
|
||
|
||
if (probes_per_objfile == NULL)
|
||
{
|
||
VEC_reserve (probe_p, probes_per_objfile, 1);
|
||
gdb_assert (probes_per_objfile != NULL);
|
||
}
|
||
|
||
set_objfile_data (objfile, probe_key, probes_per_objfile);
|
||
}
|
||
|
||
return probes_per_objfile;
|
||
}
|
||
|
||
/* Implementation of `sym_get_probe_argument_count', as documented in
|
||
symfile.h. */
|
||
|
||
static unsigned
|
||
elf_get_probe_argument_count (struct probe *probe)
|
||
{
|
||
return probe->pops->get_probe_argument_count (probe);
|
||
}
|
||
|
||
/* Implementation of `sym_evaluate_probe_argument', as documented in
|
||
symfile.h. */
|
||
|
||
static struct value *
|
||
elf_evaluate_probe_argument (struct probe *probe, unsigned n)
|
||
{
|
||
return probe->pops->evaluate_probe_argument (probe, n);
|
||
}
|
||
|
||
/* Implementation of `sym_compile_to_ax', as documented in symfile.h. */
|
||
|
||
static void
|
||
elf_compile_to_ax (struct probe *probe,
|
||
struct agent_expr *expr,
|
||
struct axs_value *value,
|
||
unsigned n)
|
||
{
|
||
probe->pops->compile_to_ax (probe, expr, value, n);
|
||
}
|
||
|
||
/* Implementation of `sym_relocate_probe', as documented in symfile.h. */
|
||
|
||
static void
|
||
elf_symfile_relocate_probe (struct objfile *objfile,
|
||
struct section_offsets *new_offsets,
|
||
struct section_offsets *delta)
|
||
{
|
||
int ix;
|
||
VEC (probe_p) *probes = objfile_data (objfile, probe_key);
|
||
struct probe *probe;
|
||
|
||
for (ix = 0; VEC_iterate (probe_p, probes, ix, probe); ix++)
|
||
probe->pops->relocate (probe, ANOFFSET (delta, SECT_OFF_TEXT (objfile)));
|
||
}
|
||
|
||
/* Helper function used to free the space allocated for storing SystemTap
|
||
probe information. */
|
||
|
||
static void
|
||
probe_key_free (struct objfile *objfile, void *d)
|
||
{
|
||
int ix;
|
||
VEC (probe_p) *probes = d;
|
||
struct probe *probe;
|
||
|
||
for (ix = 0; VEC_iterate (probe_p, probes, ix, probe); ix++)
|
||
probe->pops->destroy (probe);
|
||
|
||
VEC_free (probe_p, probes);
|
||
}
|
||
|
||
|
||
|
||
/* Implementation `sym_probe_fns', as documented in symfile.h. */
|
||
|
||
static const struct sym_probe_fns elf_probe_fns =
|
||
{
|
||
elf_get_probes, /* sym_get_probes */
|
||
elf_get_probe_argument_count, /* sym_get_probe_argument_count */
|
||
elf_evaluate_probe_argument, /* sym_evaluate_probe_argument */
|
||
elf_compile_to_ax, /* sym_compile_to_ax */
|
||
elf_symfile_relocate_probe, /* sym_relocate_probe */
|
||
};
|
||
|
||
/* 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 */
|
||
NULL, /* sym_read_psymbols */
|
||
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. */
|
||
&elf_probe_fns, /* sym_probe_fns */
|
||
&psym_functions
|
||
};
|
||
|
||
/* The same as elf_sym_fns, but not registered and lazily reads
|
||
psymbols. */
|
||
|
||
static const struct sym_fns elf_sym_fns_lazy_psyms =
|
||
{
|
||
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 */
|
||
read_psyms, /* sym_read_psymbols */
|
||
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. */
|
||
&elf_probe_fns, /* sym_probe_fns */
|
||
&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 */
|
||
NULL, /* sym_read_psymbols */
|
||
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. */
|
||
&elf_probe_fns, /* sym_probe_fns */
|
||
&dwarf2_gdb_index_functions
|
||
};
|
||
|
||
/* STT_GNU_IFUNC resolver vector to be installed to gnu_ifunc_fns_p. */
|
||
|
||
static const struct gnu_ifunc_fns elf_gnu_ifunc_fns =
|
||
{
|
||
elf_gnu_ifunc_resolve_addr,
|
||
elf_gnu_ifunc_resolve_name,
|
||
elf_gnu_ifunc_resolver_stop,
|
||
elf_gnu_ifunc_resolver_return_stop
|
||
};
|
||
|
||
void
|
||
_initialize_elfread (void)
|
||
{
|
||
probe_key = register_objfile_data_with_cleanup (NULL, probe_key_free);
|
||
add_symtab_fns (&elf_sym_fns);
|
||
|
||
elf_objfile_gnu_ifunc_cache_data = register_objfile_data ();
|
||
gnu_ifunc_fns_p = &elf_gnu_ifunc_fns;
|
||
}
|