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Yao Qi c06cbd92be Initialise target descrption after skipping extra traps for --wrapper
Nowadays, when --wrapper is used, GDBserver skips extra traps/stops
in the wrapper program, and stops at the first instruction of the
program to be debugged.  However, GDBserver created target description
in the first stop of inferior, and the executable of the inferior
is the wrapper program rather than the program to be debugged.  In
this way, the target description can be wrong if the architectures
of wrapper program and program to be debugged are different.  This
is shown by some fails in gdb.server/wrapper.exp on buildbot.

We are testing i686-linux GDB (Fedora-i686) on an x86_64-linux box
(fedora-x86-64-4) in buildbot, such configuration causes fails in
gdb.server/wrapper.exp like this:

spawn /home/gdb-buildbot-2/fedora-x86-64-4/fedora-i686/build/gdb/testsuite/../../gdb/gdbserver/gdbserver --once --wrapper env TEST=1 -- :2346 /home/gdb-buildbot-2/fedora-x86-64-4/fedora-i686/build/gdb/testsuite/outputs/gdb.server/wrapper/wrapper
Process /home/gdb-buildbot-2/fedora-x86-64-4/fedora-i686/build/gdb/testsuite/outputs/gdb.server/wrapper/wrapper created; pid = 8795
Can't debug 64-bit process with 32-bit GDBserver
Exiting
target remote localhost:2346
localhost:2346: Connection timed out.
(gdb) FAIL: gdb.server/wrapper.exp: setting breakpoint at marker

See https://sourceware.org/ml/gdb-testers/2015-q3/msg01541.html

In this case, program to be debugged ("wrapper") is 32-bit but wrapper
program ("/usr/bin/env") is 64-bit, so GDBserver gets the 64-bit
target description instead of 32-bit.

The root cause of this problem is that GDBserver creates target
description too early, and the rationale of fix could be creating
target description once the GDBserver skips extra traps and inferior
stops at the first instruction of the program we want to debug.  IOW,
when GDBserver skips extra traps, the inferior's tdesc is NULL, and
mywait and its callees shouldn't use inferior's tdesc, so in this
patch, we skip code that requires register access, see changes in
linux_resume_one_lwp_throw and need_step_over_p.

In linux_low_filter_event, if target description isn't initialised and
GDBserver attached the process, we create target description immediately,
because GDBserver don't have to skip extra traps for attach, IOW, it
makes no sense to use --attach and --wrapper together.  Otherwise, the
process is launched by GDBserver, we keep the status pending, and return.

After GDBserver skipped extra traps in start_inferior, we call a
target_ops hook arch_setup to initialise target description there.

gdb/gdbserver:

2015-07-24  Yao Qi  <yao.qi@linaro.org>

	* linux-low.c (linux_arch_setup): New function.
	(linux_low_filter_event): If proc->tdesc is NULL and
	proc->attached is true, call the_low_target.arch_setup.
	Otherwise, keep status pending, and return.
	(linux_resume_one_lwp_throw): Don't call get_pc if
	thread->while_stepping isn't NULL.  Don't call
	get_thread_regcache if proc->tdesc is NULL.
	(need_step_over_p): Return 0 if proc->tdesc is NULL.
	(linux_target_ops): Install arch_setup.
	* server.c (start_inferior): Call the_target->arch_setup.
	* target.h (struct target_ops) <arch_setup>: New field.
	(target_arch_setup): New marco.
	* lynx-low.c (lynx_target_ops): Update.
	* nto-low.c (nto_target_ops): Update.
	* spu-low.c (spu_target_ops): Update.
	* win32-low.c (win32_target_ops): Update.
2015-07-24 14:40:34 +01:00
bfd Correct reloc section name 2015-07-24 14:48:55 +09:30
binutils Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
config Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
cpu Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
elfcpp Add chdr_size, Chdr, Chdr_write and Chdr_data 2015-04-08 10:29:40 -07:00
etc PR external/{16327,16328}: Remove etc/configure.texi and etc/standards.texi. 2014-06-27 11:33:25 +02:00
gas Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
gdb Initialise target descrption after skipping extra traps for --wrapper 2015-07-24 14:40:34 +01:00
gold Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
gprof Updated translations for various binutils components. 2015-04-29 16:26:14 +01:00
include Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
intl Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
ld Replace -g with -ggdb3 in ld compress tests 2015-07-24 04:16:56 -07:00
libdecnumber Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
libiberty Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
opcodes Fix ubsan signed integer overflow 2015-07-23 12:52:46 +09:30
readline Fix executable indicator in file name completion on Windows. 2014-12-30 21:14:25 +02:00
sim Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
texinfo * texinfo/texinfo.tex: Update to version 2009-03-28.05. 2009-04-21 12:36:46 +00:00
zlib Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
.cvsignore add autom4te.cache to .cvsignore 2007-02-13 15:25:58 +00:00
.gitattributes Add a .gitattributes file for use with git-merge-changelog 2014-07-25 18:07:23 -04:00
.gitignore Sync the root .gitignore file with GCC's. 2013-01-11 15:17:35 +00:00
ChangeLog Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
compile Update from upstream Automake 2014-11-16 13:43:48 +01:00
config-ml.in Sync config-ml.in with GCC trunk 2015-03-17 05:15:34 -07:00
config.guess Update config.guess and config.sub to the latest upstream version 2015-03-30 16:28:14 -04:00
config.rpath Remove freebsd1 from libtool.m4 macros and config.rpath. 2011-02-13 21:00:14 +00:00
config.sub Update config.guess and config.sub to the latest upstream version 2015-03-30 16:28:14 -04:00
configure Sync toplevel configure with GCC 2015-07-14 08:17:27 -07:00
configure.ac Sync toplevel configure with GCC 2015-07-14 08:17:27 -07:00
COPYING
COPYING.LIB
COPYING.LIBGLOSS 2013-01-07 Jeff Johnston <jjohnstn@redhat.com> 2013-01-07 21:39:26 +00:00
COPYING.NEWLIB 2013-10-01 Jeff Johnston <jjohnstn@redhat.com> 2013-10-01 18:14:04 +00:00
COPYING3 * COPYING3: New file. Contains version 3 of the GNU General Public License. 2007-07-17 13:50:23 +00:00
COPYING3.LIB * COPYING3: New file. Contains version 3 of the GNU General Public License. 2007-07-17 13:50:23 +00:00
depcomp Update from upstream Automake 2014-11-16 13:43:48 +01:00
djunpack.bat * djunpack.bat: Use ".." quoting in Sed command, for the sake of 2009-03-27 13:37:09 +00:00
install-sh Update from upstream Automake 2014-11-16 13:43:48 +01:00
libtool.m4 Update libtool.m4 from GCC trunk 2014-11-24 09:14:09 -08:00
ltgcc.m4 * libtool.m4: Update to libtool 2.2.6. 2008-09-29 15:28:14 +00:00
ltmain.sh PR target/59788 2014-02-06 11:01:57 +01:00
ltoptions.m4 Sync Libtool from GCC. 2010-01-09 21:11:44 +00:00
ltsugar.m4 * libtool.m4: Update to libtool 2.2.6. 2008-09-29 15:28:14 +00:00
ltversion.m4 Sync Libtool from GCC. 2010-01-09 21:11:44 +00:00
lt~obsolete.m4 Sync Libtool from GCC. 2010-01-09 21:11:44 +00:00
MAINTAINERS Update description of ownership of files in include/ 2014-11-04 16:14:14 -08:00
Makefile.def Configure zlib with --enable-host-shared for shared bfd 2015-05-01 08:34:08 -07:00
Makefile.in Sync Makefile.tpl with GCC 2015-07-14 09:52:36 -07:00
Makefile.tpl Sync Makefile.tpl with GCC 2015-07-14 09:52:36 -07:00
makefile.vms
missing Update from upstream Automake 2014-11-16 13:43:48 +01:00
mkdep
mkinstalldirs Update from upstream Automake 2014-11-16 13:43:48 +01:00
move-if-change Update `move-if-change' from gnulib 2014-11-16 17:04:02 +01:00
README
README-maintainer-mode Cleanups after the update to Autoconf 2.64, Automake 1.11. 2009-08-22 17:08:11 +00:00
setup.com 2009-09-01 Tristan Gingold <gingold@adacore.com> 2009-09-01 13:38:26 +00:00
src-release.sh Adjust src-release.sh for sim using the gdb create-version.sh. 2015-04-15 04:08:51 +02:00
symlink-tree
ylwrap Update from upstream Automake 2014-11-16 13:43:48 +01:00

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.