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Pedro Alves fbea99ea8a Implement all-stop on top of a target running non-stop mode
This finally implements user-visible all-stop mode running with the
target_ops backend always in non-stop mode.  This is a stepping stone
towards finer-grained control of threads, being able to do interesting
things like thread groups, associating groups with breakpoints, etc.
From the user's perspective, all-stop mode is really just a special
case of being able to stop and resume specific sets of threads, so it
makes sense to do this step first.

With this, even in all-stop, the target is no longer in charge of
stopping all threads before reporting an event to the core -- the core
takes care of it when it sees fit.  For example, when "next"- or
"step"-ing, we can avoid stopping and resuming all threads at each
internal single-step, and instead only stop all threads when we're
about to present the stop to the user.

The implementation is almost straight forward, as the heavy lifting
has been done already in previous patches.  Basically, we replace
checks for "set non-stop on/off" (the non_stop global), with calls to
a new target_is_non_stop_p function.  In a few places, if "set
non-stop off", we stop all threads explicitly, and in a few other
places we resume all threads explicitly, making use of existing
methods that were added for teaching non-stop to step over breakpoints
without displaced stepping.

This adds a new "maint set target-non-stop on/off/auto" knob that
allows both disabling the feature if we find problems, and
force-enable it for development (useful when teaching a target about
this.  The default is "auto", which means the feature is enabled if a
new target method says it should be enabled.  The patch implements the
method in linux-nat.c, just for illustration, because it still returns
false.  We'll need a few follow up fixes before turning it on by
default.  This is a separate target method from indicating regular
non-stop support, because e.g., while e.g., native linux-nat.c is
close to regression free with all-stop-non-stop (with following
patches will fixing the remaining regressions), remote.c+gdbserver
will still need more fixing, even though it supports "set non-stop
on".

Tested on x86_64 Fedora 20, native, with and without "set displaced
off", and with and without "maint set target-non-stop on"; and also
against gdbserver.

gdb/ChangeLog:
2015-08-07  Pedro Alves  <palves@redhat.com>

	* NEWS: Mention "maint set/show target-non-stop".
	* breakpoint.c (update_global_location_list): Check
	target_is_non_stop_p instead of non_stop.
	* infcmd.c (attach_command_post_wait, attach_command): Likewise.
	* infrun.c (show_can_use_displaced_stepping)
	(can_use_displaced_stepping_p, start_step_over_inferior):
	Likewise.
	(internal_resume_ptid): New function.
	(resume): Use it.
	(proceed): Check target_is_non_stop_p instead of non_stop.  If in
	all-stop mode but the target is always in non-stop mode, start all
	the other threads that are implicitly resumed too.
	(for_each_just_stopped_thread, fetch_inferior_event)
	(adjust_pc_after_break, stop_all_threads): Check
	target_is_non_stop_p instead of non_stop.
	(handle_inferior_event): Likewise.  Handle detach-fork in all-stop
	with the target always in non-stop mode.
	(handle_signal_stop) <random signal>: Check target_is_non_stop_p
	instead of non_stop.
	(switch_back_to_stepped_thread): Check target_is_non_stop_p
	instead of non_stop.
	(keep_going_stepped_thread): Use internal_resume_ptid.
	(stop_waiting): If in all-stop mode, and the target is in non-stop
	mode, stop all threads.
	(keep_going_pass): Likewise, when starting a new in-line step-over
	sequence.
	* linux-nat.c (get_pending_status, select_event_lwp)
	(linux_nat_filter_event, linux_nat_wait_1, linux_nat_wait): Check
	target_is_non_stop_p instead of non_stop.
	(linux_nat_always_non_stop_p): New function.
	(linux_nat_stop): Check target_is_non_stop_p instead of non_stop.
	(linux_nat_add_target): Install linux_nat_always_non_stop_p.
	* target-delegates.c: Regenerate.
	* target.c (target_is_non_stop_p): New function.
	(target_non_stop_enabled, target_non_stop_enabled_1): New globals.
	(maint_set_target_non_stop_command)
	(maint_show_target_non_stop_command): New functions.
	(_initilize_target): Install "maint set/show target-non-stop"
	commands.
	* target.h (struct target_ops) <to_always_non_stop_p>: New field.
	(target_non_stop_enabled): New declaration.
	(target_is_non_stop_p): New declaration.

gdb/doc/ChangeLog:
2015-08-07  Pedro Alves  <palves@redhat.com>

	* gdb.texinfo (Maintenance Commands): Document "maint set/show
	target-non-stop".
2015-08-07 17:24:01 +01:00
bfd Properly merge hidden versioned symbol 2015-08-07 05:04:35 -07:00
binutils objcopy: Improve wildcard matching for symbols with '!' prefix. 2015-08-07 11:41:40 +02:00
config Sync config with GCC 2015-07-27 07:43:26 -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
gas 2015-08-04 Thomas Preud'homme <thomas.preudhomme@arm.com> 2015-08-04 09:39:42 +08:00
gdb Implement all-stop on top of a target running non-stop mode 2015-08-07 17:24:01 +01:00
gold Regenerate configure files 2015-07-27 07:56:32 -07:00
gprof Regenerate configure files 2015-07-27 07:56:32 -07:00
include Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
intl Yaakov Selkowitz: fixes for in-tree libiconv 2015-08-06 23:55:06 -04:00
ld Properly merge hidden versioned symbol 2015-08-07 05:04:35 -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 Remove CpuFMA4 support from CPU_ZNVER1_FLAGS. 2015-08-07 07:31:51 -07:00
readline Revert "Sync readline/ to version 7.0 alpha" 2015-07-25 15:57:00 -04:00
sim Fix building GDB for the M32C by providing a stub sim_info function. 2015-08-05 14:58:21 +01:00
texinfo
zlib Remove leading/trailing white spaces in ChangeLog 2015-07-24 04:16:47 -07:00
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compile Update from upstream Automake 2014-11-16 13:43:48 +01:00
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configure.ac Sync toplevel files with GCC 2015-07-27 07:49:05 -07:00
COPYING
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djunpack.bat
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lt~obsolete.m4
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MAINTAINERS
Makefile.def Yaakov Selkowitz: fixes for in-tree libiconv 2015-08-06 23:55:06 -04:00
Makefile.in Yaakov Selkowitz: fixes for in-tree libiconv 2015-08-06 23:55:06 -04:00
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README
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src-release.sh Adjust src-release.sh for sim using the gdb create-version.sh. 2015-04-15 04:08:51 +02:00
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		   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
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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

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on where and how to report problems.