binutils-gdb/gdb/objfile-flags.h
Sergio Durigan Junior 97cbe998d0 Add support for the readnever concept
The purpose of this concept is to turn the load of debugging
information off, either globally (via the '--readnever' option), or
objfile-specific.  The implementation proposed here is an extension of
the patch distributed with Fedora GDB; looking at the Fedora patch
itself and the history, one can see some reasons why it was never
resubmitted:

  - The patch appears to have been introduced as a workaround, at
    least initially;
  - The patch is far from perfect, as it simply shunts the load of
    DWARF debugging information, without really worrying about the
    other debug format.
  - Who really does non-symbolic debugging anyways?

One use of this feature is when a user simply wants to do the
following sequence: attach, dump core, detach.  Loading the debugging
information in this case is an unnecessary cause of delay.

This patch expands the version shipped with Fedora GDB in order to
make the feature available for all the debuginfo backends, not only
for DWARF.  It also implements a per-objfile flag which can be
activated by using the "-readnever" command when using the
'add-symbol-file' or 'symbol-file' commands.

It's also worth mentioning that this patch tests whether GDB correctly
fails to initialize if both '--readnow' and '--readnever' options are
passed.

Tested on the BuildBot.

gdb/ChangeLog:

2017-12-01  Andrew Cagney  <cagney@redhat.com>
	    Joel Brobecker  <brobecker@adacore.com>
	    Sergio Durigan Junior  <sergiodj@redhat.com>

	* NEWS (Changes since GDB 8.0: Mention new '--readnever'
	feature.
	* coffread.c (coff_symfile_read): Do not map over sections with
	'coff_locate_sections' if readnever is on.
	* dwarf2read.c (dwarf2_has_info): Return 0 if
	readnever is on.
	* elfread.c (elf_symfile_read): Do not map over sections with
	'elf_locate_sections' if readnever is on.
	* main.c (validate_readnow_readnever): New function.
	(captured_main_1): Add support for --readnever.
	(print_gdb_help): Document --readnever.
	* objfile-flags.h (enum objfile_flag) <OBJF_READNEVER>: New
	flag.
	* symfile.c (readnever_symbol_files): New global.
	(symbol_file_add_with_addrs): Set 'OBJF_READNEVER' when
	'READNEVER_SYMBOL_FILES' is set.
	(validate_readnow_readnever): New function.
	(symbol_file_command): Handle '-readnever' option.
	Call 'validate_readnow_readnever'.
	(add_symbol_file_command): Handle '-readnever' option.
	Call 'validate_readnow_readnever'.
	(_initialize_symfile): Document new '-readnever' option for
	both 'symbol-file' and 'add-symbol-file' commands.
	* top.h (readnever_symbol_files): New extern global.
	* xcoffread.c (xcoff_initial_scan): Do not read debug
	information if readnever is on.

gdb/doc/ChangeLog:

2017-12-01  Andrew Cagney  <cagney@redhat.com>
	    Joel Brobecker  <brobecker@adacore.com>
	    Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.texinfo (File Options): Document --readnever.
	(Commands to Specify Files): Likewise, for 'symbol-file' and
	'add-symbol-file'.

gdb/testsuite/ChangeLog:

2017-12-01  Joel Brobecker  <brobecker@adacore.com>
	    Sergio Durigan Junior  <sergiodj@redhat.com>
	    Pedro Alves  <palves@redhat.com>

	* gdb.base/readnever.c, gdb.base/readnever.exp: New files.
2017-12-01 21:28:31 -05:00

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2.9 KiB
C

/* Definition of objfile flags.
Copyright (C) 1992-2017 Free Software Foundation, Inc.
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/>. */
#if !defined (OBJFILE_FLAGS_H)
#define OBJFILE_FLAGS_H
#include "common/enum-flags.h"
/* Defines for the objfile flags field. Defined in a separate file to
break circular header dependencies. */
enum objfile_flag
{
/* When an object file has its functions reordered (currently
Irix-5.2 shared libraries exhibit this behaviour), we will need
an expensive algorithm to locate a partial symtab or symtab via
an address. To avoid this penalty for normal object files, we
use this flag, whose setting is determined upon symbol table
read in. */
OBJF_REORDERED = 1 << 0, /* Functions are reordered */
/* Distinguish between an objfile for a shared library and a
"vanilla" objfile. This may come from a target's
implementation of the solib interface, from add-symbol-file, or
any other mechanism that loads dynamic objects. */
OBJF_SHARED = 1 << 1, /* From a shared library */
/* User requested that this objfile be read in it's entirety. */
OBJF_READNOW = 1 << 2, /* Immediate full read */
/* This objfile was created because the user explicitly caused it
(e.g., used the add-symbol-file command). This bit offers a
way for run_command to remove old objfile entries which are no
longer valid (i.e., are associated with an old inferior), but
to preserve ones that the user explicitly loaded via the
add-symbol-file command. */
OBJF_USERLOADED = 1 << 3, /* User loaded */
/* Set if we have tried to read partial symtabs for this objfile.
This is used to allow lazy reading of partial symtabs. */
OBJF_PSYMTABS_READ = 1 << 4,
/* Set if this is the main symbol file (as opposed to symbol file
for dynamically loaded code). */
OBJF_MAINLINE = 1 << 5,
/* ORIGINAL_NAME and OBFD->FILENAME correspond to text description
unrelated to filesystem names. It can be for example
"<image in memory>". */
OBJF_NOT_FILENAME = 1 << 6,
/* User requested that we do not read this objfile's symbolic
information. */
OBJF_READNEVER = 1 << 7,
};
DEF_ENUM_FLAGS_TYPE (enum objfile_flag, objfile_flags);
#endif /* !defined (OBJFILE_FLAGS_H) */