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binutils-gdb/gdb/gdbthread.h
Pedro Alves 0803633106 Per-inferior thread list, thread ranges/iterators, down with ALL_THREADS, etc. 
As preparation for multi-target, this patch makes each inferior have
its own thread list.

This isn't absolutely necessary for multi-target, but simplifies
things.  It originally stemmed from the desire to eliminate the
init_thread_list calls sprinkled around, plus it makes it more
efficient to iterate over threads of a given inferior (no need to
always iterate over threads of all inferiors).

We still need to iterate over threads of all inferiors in a number of
places, which means we'd need adjust the ALL_THREADS /
ALL_NON_EXITED_THREADS macros.  However, naively tweaking those macros
to have an extra for loop, like:

     #define ALL_THREADS (thr, inf) \
       for (inf = inferior_list; inf; inf = inf->next) \
	 for (thr = inf->thread_list; thr; thr = thr->next)

causes problems with code that does "break" or "continue" within the
ALL_THREADS loop body.  Plus, we need to declare the extra "inf" local
variable in order to pass it as temporary variable to ALL_THREADS
(etc.)

It gets even trickier when we consider extending the macros to filter
out threads matching a ptid_t and a target.  The macros become tricker
to read/write.  Been there.

An alternative (which was my next attempt), is to replace the
ALL_THREADS etc. iteration style with for_each_all_threads,
for_each_non_exited_threads, etc. functions which would take a
callback as parameter, which would usually be passed a lambda.
However, I did not find that satisfactory at all, because the
resulting code ends up a little less natural / more noisy to read,
write and debug/step-through (due to use of lambdas), and in many
places where we use "continue;" to skip to the next thread now need to
use "return;".  (I ran into hard to debug bugs caused by a
continue/return confusion.)

I.e., before:

    ALL_NON_EXITED_THREADS (tp)
      {
	if (tp->not_what_I_want)
	  continue;
	// do something
      }

would turn into:

    for_each_non_exited_thread ([&] (thread_info *tp)
      {
	if (tp->not_what_I_want)
	  return;
	// do something
      });

Lastly, the solution I settled with was to replace the ALL_THREADS /
ALL_NON_EXITED_THREADS / ALL_INFERIORS macros with (C++20-like) ranges
and iterators, such that you can instead naturaly iterate over
threads/inferiors using range-for, like e.g,.:

   // all threads, including THREAD_EXITED threads.
   for (thread_info *tp : all_threads ())
     { .... }

   // all non-exited threads.
   for (thread_info *tp : all_non_exited_threads ())
     { .... }

   // all non-exited threads of INF inferior.
   for (thread_info *tp : inf->non_exited_threads ())
     { .... }

The all_non_exited_threads() function takes an optional filter ptid_t as
parameter, which is quite convenient when we need to iterate over
threads matching that filter.  See e.g., how the
set_executing/set_stop_requested/finish_thread_state etc. functions in
thread.c end up being simplified.

Most of the patch thus is about adding the infrustructure for allowing
the above.  Later on when we get to actual multi-target, these
functions/ranges/iterators will gain a "target_ops *" parameter so
that e.g., we can iterate over all threads of a given target that
match a given filter ptid_t.

The only entry points users needs to be aware of are the
all_threads/all_non_exited_threads etc. functions seen above.  Thus,
those functions are declared in gdbthread.h/inferior.h.  The actual
iterators/ranges are mainly "internals" and thus are put out of view
in the new thread-iter.h/thread-iter.c/inferior-iter.h files.  That
keeps the gdbthread.h/inferior.h headers quite a bit more readable.

A common/safe-iterator.h header is added which adds a template that
can be used to build "safe" iterators, which are forward iterators
that can be used to replace the ALL_THREADS_SAFE macro and other
instances of the same idiom in future.

There's a little bit of shuffling of code between
gdbthread.h/thread.c/inferior.h in the patch.  That is necessary in
order to avoid circular dependencies between the
gdbthread.h/inferior.h headers.

As for the init_thread_list calls sprinkled around, they're all
eliminated by this patch, and a new, central call is added to
inferior_appeared.  Note how also related to that, there's a call to
init_wait_for_inferior in remote.c that is eliminated.
init_wait_for_inferior is currently responsible for discarding skipped
inline frames, which had to be moved elsewhere.  Given that nowadays
we always have a thread even for single-threaded processes, the
natural place is to delete a frame's inline frame info when we delete
the thread.  I.e., from clear_thread_inferior_resources.

gdb/ChangeLog:
2018-11-22  Pedro Alves  <palves@redhat.com>

	* Makefile.in (COMMON_SFILES): Add thread-iter.c.
	* breakpoint.c (breakpoints_should_be_inserted_now): Replace
	ALL_NON_EXITED_THREADS with all_non_exited_threads.
	(print_one_breakpoint_location): Replace ALL_INFERIORS with
	all_inferiors.
	* bsd-kvm.c: Include inferior.h.
	* btrace.c (btrace_free_objfile): Replace ALL_NON_EXITED_THREADS
	with all_non_exited_threads.
	* common/filtered-iterator.h: New.
	* common/safe-iterator.h: New.
	* corelow.c (core_target_open): Don't call init_thread_list here.
	* darwin-nat.c (thread_info_from_private_thread_info): Replace
	ALL_THREADS with all_threads.
	* fbsd-nat.c (fbsd_nat_target::resume): Replace
	ALL_NON_EXITED_THREADS with inf->non_exited_threads.
	* fbsd-tdep.c (fbsd_make_corefile_notes): Replace
	ALL_NON_EXITED_THREADS with inf->non_exited_threads.
	* fork-child.c (postfork_hook): Don't call init_thread_list here.
	* gdbarch-selftests.c (register_to_value_test): Adjust.
	* gdbthread.h: Don't include "inferior.h" here.
	(struct inferior): Forward declare.
	(enum step_over_calls_kind): Moved here from inferior.h.
	(thread_info::deletable): Definition moved to thread.c.
	(find_thread_ptid (inferior *, ptid_t)): Declare.
	(ALL_THREADS, ALL_THREADS_BY_INFERIOR, ALL_THREADS_SAFE): Delete.
	Include "thread-iter.h".
	(all_threads, all_non_exited_threads, all_threads_safe): New.
	(any_thread_p): Declare.
	(thread_list): Delete.
	* infcmd.c (signal_command): Replace ALL_NON_EXITED_THREADS with
	all_non_exited_threads.
	(proceed_after_attach_callback): Delete.
	(proceed_after_attach): Take an inferior pointer instead of an
	integer PID.  Adjust to use range-for.
	(attach_post_wait): Pass down inferior pointer instead of pid.
	Use range-for instead of ALL_NON_EXITED_THREADS.
	(detach_command): Remove init_thread_list call.
	* inferior-iter.h: New.
	* inferior.c (struct delete_thread_of_inferior_arg): Delete.
	(delete_thread_of_inferior): Delete.
	(delete_inferior, exit_inferior_1): Use range-for with
	inf->threads_safe() instead of iterate_over_threads.
	(inferior_appeared): Call init_thread_list here.
	(discard_all_inferiors): Use all_non_exited_inferiors.
	(find_inferior_id, find_inferior_pid): Use all_inferiors.
	(iterate_over_inferiors): Use all_inferiors_safe.
	(have_inferiors, number_of_live_inferiors): Use
	all_non_exited_inferiors.
	(number_of_inferiors): Use all_inferiors and std::distance.
	(print_inferior): Use all_inferiors.
	* inferior.h: Include gdbthread.h.
	(enum step_over_calls_kind): Moved to gdbthread.h.
	(struct inferior) <thread_list>: New field.
	<threads, non_exited_threads, threads_safe>: New methods.
	(ALL_INFERIORS): Delete.
	Include "inferior-iter.h".
	(ALL_NON_EXITED_INFERIORS): Delete.
	(all_inferiors_safe, all_inferiors, all_non_exited_inferiors): New
	functions.
	* inflow.c (child_interrupt, child_pass_ctrlc): Replace
	ALL_NON_EXITED_THREADS with all_non_exited_threads.
	* infrun.c (follow_exec): Use all_threads_safe.
	(clear_proceed_status, proceed): Use all_non_exited_threads.
	(init_wait_for_inferior): Don't clear inline frame state here.
	(infrun_thread_stop_requested, for_each_just_stopped_thread): Use
	all_threads instead of ALL_NON_EXITED_THREADS.
	(random_pending_event_thread): Use all_non_exited_threads instead
	of ALL_NON_EXITED_THREADS.  Use a lambda for repeated code.
	(clean_up_just_stopped_threads_fsms): Use all_non_exited_threads
	instead of ALL_NON_EXITED_THREADS.
	(handle_no_resumed): Use all_non_exited_threads instead of
	ALL_NON_EXITED_THREADS.  Use all_inferiors instead of
	ALL_INFERIORS.
	(restart_threads, switch_back_to_stepped_thread): Use
	all_non_exited_threads instead of ALL_NON_EXITED_THREADS.
	* linux-nat.c (check_zombie_leaders): Replace ALL_INFERIORS with
	all_inferiors.
	(kill_unfollowed_fork_children): Use inf->non_exited_threads
	instead of ALL_NON_EXITED_THREADS.
	* linux-tdep.c (linux_make_corefile_notes): Use
	inf->non_exited_threads instead of ALL_NON_EXITED_THREADS.
	* linux-thread-db.c (thread_db_target::update_thread_list):
	Replace ALL_INFERIORS with all_inferiors.
	(thread_db_target::thread_handle_to_thread_info): Use
	inf->non_exited_threads instead of ALL_NON_EXITED_THREADS.
	* mi/mi-interp.c (multiple_inferiors_p): New.
	(mi_on_resume_1): Simplify using all_non_exited_threads and
	multiple_inferiors_p.
	* mi/mi-main.c (mi_cmd_thread_list_ids): Use all_non_exited_threads
	instead of ALL_NON_EXITED_THREADS.
	* nto-procfs.c (nto_procfs_target::open): Don't call
	init_thread_list here.
	* record-btrace.c (record_btrace_target_open)
	(record_btrace_target::stop_recording)
	(record_btrace_target::close)
	(record_btrace_target::record_is_replaying)
	(record_btrace_target::resume, record_btrace_target::wait)
	(record_btrace_target::record_stop_replaying): Use
	all_non_exited_threads instead of ALL_NON_EXITED_THREADS.
	* record-full.c (record_full_wait_1): Use all_non_exited_threads
	instead of ALL_NON_EXITED_THREADS.
	* regcache.c (cooked_read_test): Remove reference to global
	thread_list.
	* remote-sim.c (gdbsim_target::create_inferior): Don't call
	init_thread_list here.
	* remote.c (remote_target::update_thread_list): Use
	all_threads_safe instead of ALL_NON_EXITED_THREADS.
	(remote_target::process_initial_stop_replies): Replace
	ALL_INFERIORS with all_non_exited_inferiors and use
	all_non_exited_threads instead of ALL_NON_EXITED_THREADS.
	(remote_target::open_1): Don't call init_thread_list here.
	(remote_target::append_pending_thread_resumptions)
	(remote_target::remote_resume_with_hc): Use all_non_exited_threads
	instead of ALL_NON_EXITED_THREADS.
	(remote_target::commit_resume)
	(remote_target::remove_new_fork_children): Replace ALL_INFERIORS
	with all_non_exited_inferiors and use all_non_exited_threads
	instead of ALL_NON_EXITED_THREADS.
	(remote_target::kill_new_fork_children): Use
	all_non_exited_threads instead of ALL_NON_EXITED_THREADS.  Remove
	init_thread_list and init_wait_for_inferior calls.
	(remote_target::remote_btrace_maybe_reopen)
	(remote_target::thread_handle_to_thread_info): Use
	all_non_exited_threads instead of ALL_NON_EXITED_THREADS.
	* target.c (target_terminal::restore_inferior)
	(target_terminal_is_ours_kind): Replace ALL_INFERIORS with
	all_non_exited_inferiors.
	* thread-iter.c: New file.
	* thread-iter.h: New file.
	* thread.c: Include "inline-frame.h".
	(thread_list): Delete.
	(clear_thread_inferior_resources): Call clear_inline_frame_state.
	(init_thread_list): Use all_threads_safe instead of
	ALL_THREADS_SAFE.  Adjust to per-inferior thread lists.
	(new_thread): Adjust to per-inferior thread lists.
	(add_thread_silent): Pass inferior to find_thread_ptid.
	(thread_info::deletable): New, moved from the header.
	(delete_thread_1): Adjust to per-inferior thread lists.
	(find_thread_global_id): Use inf->threads().
	(find_thread_ptid): Use find_inferior_ptid and pass inferior to
	find_thread_ptid.
	(find_thread_ptid(inferior*, ptid_t)): New overload.
	(iterate_over_threads): Use all_threads_safe.
	(any_thread_p): New.
	(thread_count): Use all_threads and std::distance.
	(live_threads_count): Use all_non_exited_threads and
	std::distance.
	(valid_global_thread_id): Use all_threads.
	(in_thread_list): Use find_thread_ptid.
	(first_thread_of_inferior): Adjust to per-inferior thread lists.
	(any_thread_of_inferior, any_live_thread_of_inferior): Use
	inf->non_exited_threads().
	(prune_threads, delete_exited_threads): Use all_threads_safe.
	(thread_change_ptid): Pass inferior pointer to find_thread_ptid.
	(set_resumed, set_running): Use all_non_exited_threads.
	(is_thread_state, is_stopped, is_exited, is_running)
	(is_executing): Delete.
	(set_executing, set_stop_requested, finish_thread_state): Use
	all_non_exited_threads.
	(print_thread_info_1): Use all_inferiors and all_threads.
	(thread_apply_all_command): Use all_non_exited_threads.
	(thread_find_command): Use all_threads.
	(update_threads_executing): Use all_non_exited_threads.
	* tid-parse.c (parse_thread_id): Use inf->threads.
	* x86-bsd-nat.c (x86bsd_dr_set): Use inf->non_exited_threads ().
2018-11-22 16:13:23 +00:00

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/* Multi-process/thread control defs for GDB, the GNU debugger.
Copyright (C) 1987-2018 Free Software Foundation, Inc.
Contributed by Lynx Real-Time Systems, Inc. Los Gatos, CA.
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/>. */
#ifndef GDBTHREAD_H
#define GDBTHREAD_H
struct symtab;
#include "breakpoint.h"
#include "frame.h"
#include "ui-out.h"
#include "btrace.h"
#include "common/vec.h"
#include "target/waitstatus.h"
#include "cli/cli-utils.h"
#include "common/refcounted-object.h"
#include "common-gdbthread.h"
struct inferior;
/* Frontend view of the thread state. Possible extensions: stepping,
finishing, until(ling),... */
enum thread_state
{
THREAD_STOPPED,
THREAD_RUNNING,
THREAD_EXITED,
};
/* STEP_OVER_ALL means step over all subroutine calls.
STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions.
STEP_OVER_NONE means don't step over any subroutine calls. */
enum step_over_calls_kind
{
STEP_OVER_NONE,
STEP_OVER_ALL,
STEP_OVER_UNDEBUGGABLE
};
/* Inferior thread specific part of `struct infcall_control_state'.
Inferior process counterpart is `struct inferior_control_state'. */
struct thread_control_state
{
/* User/external stepping state. */
/* Step-resume or longjmp-resume breakpoint. */
struct breakpoint *step_resume_breakpoint = nullptr;
/* Exception-resume breakpoint. */
struct breakpoint *exception_resume_breakpoint = nullptr;
/* Breakpoints used for software single stepping. Plural, because
it may have multiple locations. E.g., if stepping over a
conditional branch instruction we can't decode the condition for,
we'll need to put a breakpoint at the branch destination, and
another at the instruction after the branch. */
struct breakpoint *single_step_breakpoints = nullptr;
/* Range to single step within.
If this is nonzero, respond to a single-step signal by continuing
to step if the pc is in this range.
If step_range_start and step_range_end are both 1, it means to
step for a single instruction (FIXME: it might clean up
wait_for_inferior in a minor way if this were changed to the
address of the instruction and that address plus one. But maybe
not). */
CORE_ADDR step_range_start = 0; /* Inclusive */
CORE_ADDR step_range_end = 0; /* Exclusive */
/* Function the thread was in as of last it started stepping. */
struct symbol *step_start_function = nullptr;
/* If GDB issues a target step request, and this is nonzero, the
target should single-step this thread once, and then continue
single-stepping it without GDB core involvement as long as the
thread stops in the step range above. If this is zero, the
target should ignore the step range, and only issue one single
step. */
int may_range_step = 0;
/* Stack frame address as of when stepping command was issued.
This is how we know when we step into a subroutine call, and how
to set the frame for the breakpoint used to step out. */
struct frame_id step_frame_id {};
/* Similarly, the frame ID of the underlying stack frame (skipping
any inlined frames). */
struct frame_id step_stack_frame_id {};
/* Nonzero if we are presently stepping over a breakpoint.
If we hit a breakpoint or watchpoint, and then continue, we need
to single step the current thread with breakpoints disabled, to
avoid hitting the same breakpoint or watchpoint again. And we
should step just a single thread and keep other threads stopped,
so that other threads don't miss breakpoints while they are
removed.
So, this variable simultaneously means that we need to single
step the current thread, keep other threads stopped, and that
breakpoints should be removed while we step.
This variable is set either:
- in proceed, when we resume inferior on user's explicit request
- in keep_going, if handle_inferior_event decides we need to
step over breakpoint.
The variable is cleared in normal_stop. The proceed calls
wait_for_inferior, which calls handle_inferior_event in a loop,
and until wait_for_inferior exits, this variable is changed only
by keep_going. */
int trap_expected = 0;
/* Nonzero if the thread is being proceeded for a "finish" command
or a similar situation when return value should be printed. */
int proceed_to_finish = 0;
/* Nonzero if the thread is being proceeded for an inferior function
call. */
int in_infcall = 0;
enum step_over_calls_kind step_over_calls = STEP_OVER_NONE;
/* Nonzero if stopped due to a step command. */
int stop_step = 0;
/* Chain containing status of breakpoint(s) the thread stopped
at. */
bpstat stop_bpstat = nullptr;
/* Whether the command that started the thread was a stepping
command. This is used to decide whether "set scheduler-locking
step" behaves like "on" or "off". */
int stepping_command = 0;
};
/* Inferior thread specific part of `struct infcall_suspend_state'. */
struct thread_suspend_state
{
/* Last signal that the inferior received (why it stopped). When
the thread is resumed, this signal is delivered. Note: the
target should not check whether the signal is in pass state,
because the signal may have been explicitly passed with the
"signal" command, which overrides "handle nopass". If the signal
should be suppressed, the core will take care of clearing this
before the target is resumed. */
enum gdb_signal stop_signal = GDB_SIGNAL_0;
/* The reason the thread last stopped, if we need to track it
(breakpoint, watchpoint, etc.) */
enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
/* The waitstatus for this thread's last event. */
struct target_waitstatus waitstatus {};
/* If true WAITSTATUS hasn't been handled yet. */
int waitstatus_pending_p = 0;
/* Record the pc of the thread the last time it stopped. (This is
not the current thread's PC as that may have changed since the
last stop, e.g., "return" command, or "p $pc = 0xf000").
- If the thread's PC has not changed since the thread last
stopped, then proceed skips a breakpoint at the current PC,
otherwise we let the thread run into the breakpoint.
- If the thread has an unprocessed event pending, as indicated by
waitstatus_pending_p, this is used in coordination with
stop_reason: if the thread's PC has changed since the thread
last stopped, a pending breakpoint waitstatus is discarded.
- If the thread is running, this is set to -1, to avoid leaving
it with a stale value, to make it easier to catch bugs. */
CORE_ADDR stop_pc = 0;
};
/* Base class for target-specific thread data. */
struct private_thread_info
{
virtual ~private_thread_info () = 0;
};
/* Threads are intrusively refcounted objects. Being the
user-selected thread is normally considered an implicit strong
reference and is thus not accounted in the refcount, unlike
inferior objects. This is necessary, because there's no "current
thread" pointer. Instead the current thread is inferred from the
inferior_ptid global. However, when GDB needs to remember the
selected thread to later restore it, GDB bumps the thread object's
refcount, to prevent something deleting the thread object before
reverting back (e.g., due to a "kill" command). If the thread
meanwhile exits before being re-selected, then the thread object is
left listed in the thread list, but marked with state
THREAD_EXITED. (See make_cleanup_restore_current_thread and
delete_thread). All other thread references are considered weak
references. Placing a thread in the thread list is an implicit
strong reference, and is thus not accounted for in the thread's
refcount. */
class thread_info : public refcounted_object
{
public:
explicit thread_info (inferior *inf, ptid_t ptid);
~thread_info ();
bool deletable () const;
/* Mark this thread as running and notify observers. */
void set_running (bool running);
struct thread_info *next = NULL;
ptid_t ptid; /* "Actual process id";
In fact, this may be overloaded with
kernel thread id, etc. */
/* Each thread has two GDB IDs.
a) The thread ID (Id). This consists of the pair of:
- the number of the thread's inferior and,
- the thread's thread number in its inferior, aka, the
per-inferior thread number. This number is unique in the
inferior but not unique between inferiors.
b) The global ID (GId). This is a a single integer unique
between all inferiors.
E.g.:
(gdb) info threads -gid
Id GId Target Id Frame
* 1.1 1 Thread A 0x16a09237 in foo () at foo.c:10
1.2 3 Thread B 0x15ebc6ed in bar () at foo.c:20
1.3 5 Thread C 0x15ebc6ed in bar () at foo.c:20
2.1 2 Thread A 0x16a09237 in foo () at foo.c:10
2.2 4 Thread B 0x15ebc6ed in bar () at foo.c:20
2.3 6 Thread C 0x15ebc6ed in bar () at foo.c:20
Above, both inferiors 1 and 2 have threads numbered 1-3, but each
thread has its own unique global ID. */
/* The thread's global GDB thread number. This is exposed to MI,
Python/Scheme, visible with "info threads -gid", and is also what
the $_gthread convenience variable is bound to. */
int global_num;
/* The per-inferior thread number. This is unique in the inferior
the thread belongs to, but not unique between inferiors. This is
what the $_thread convenience variable is bound to. */
int per_inf_num;
/* The inferior this thread belongs to. */
struct inferior *inf;
/* The name of the thread, as specified by the user. This is NULL
if the thread does not have a user-given name. */
char *name = NULL;
/* Non-zero means the thread is executing. Note: this is different
from saying that there is an active target and we are stopped at
a breakpoint, for instance. This is a real indicator whether the
thread is off and running. */
int executing = 0;
/* Non-zero if this thread is resumed from infrun's perspective.
Note that a thread can be marked both as not-executing and
resumed at the same time. This happens if we try to resume a
thread that has a wait status pending. We shouldn't let the
thread really run until that wait status has been processed, but
we should not process that wait status if we didn't try to let
the thread run. */
int resumed = 0;
/* Frontend view of the thread state. Note that the THREAD_RUNNING/
THREAD_STOPPED states are different from EXECUTING. When the
thread is stopped internally while handling an internal event,
like a software single-step breakpoint, EXECUTING will be false,
but STATE will still be THREAD_RUNNING. */
enum thread_state state = THREAD_STOPPED;
/* State of GDB control of inferior thread execution.
See `struct thread_control_state'. */
thread_control_state control;
/* State of inferior thread to restore after GDB is done with an inferior
call. See `struct thread_suspend_state'. */
thread_suspend_state suspend;
int current_line = 0;
struct symtab *current_symtab = NULL;
/* Internal stepping state. */
/* Record the pc of the thread the last time it was resumed. (It
can't be done on stop as the PC may change since the last stop,
e.g., "return" command, or "p $pc = 0xf000"). This is maintained
by proceed and keep_going, and among other things, it's used in
adjust_pc_after_break to distinguish a hardware single-step
SIGTRAP from a breakpoint SIGTRAP. */
CORE_ADDR prev_pc = 0;
/* Did we set the thread stepping a breakpoint instruction? This is
used in conjunction with PREV_PC to decide whether to adjust the
PC. */
int stepped_breakpoint = 0;
/* Should we step over breakpoint next time keep_going is called? */
int stepping_over_breakpoint = 0;
/* Should we step over a watchpoint next time keep_going is called?
This is needed on targets with non-continuable, non-steppable
watchpoints. */
int stepping_over_watchpoint = 0;
/* Set to TRUE if we should finish single-stepping over a breakpoint
after hitting the current step-resume breakpoint. The context here
is that GDB is to do `next' or `step' while signal arrives.
When stepping over a breakpoint and signal arrives, GDB will attempt
to skip signal handler, so it inserts a step_resume_breakpoint at the
signal return address, and resume inferior.
step_after_step_resume_breakpoint is set to TRUE at this moment in
order to keep GDB in mind that there is still a breakpoint to step over
when GDB gets back SIGTRAP from step_resume_breakpoint. */
int step_after_step_resume_breakpoint = 0;
/* Pointer to the state machine manager object that handles what is
left to do for the thread's execution command after the target
stops. Several execution commands use it. */
struct thread_fsm *thread_fsm = NULL;
/* This is used to remember when a fork or vfork event was caught by
a catchpoint, and thus the event is to be followed at the next
resume of the thread, and not immediately. */
struct target_waitstatus pending_follow;
/* True if this thread has been explicitly requested to stop. */
int stop_requested = 0;
/* The initiating frame of a nexting operation, used for deciding
which exceptions to intercept. If it is null_frame_id no
bp_longjmp or bp_exception but longjmp has been caught just for
bp_longjmp_call_dummy. */
struct frame_id initiating_frame = null_frame_id;
/* Private data used by the target vector implementation. */
std::unique_ptr<private_thread_info> priv;
/* Branch trace information for this thread. */
struct btrace_thread_info btrace {};
/* Flag which indicates that the stack temporaries should be stored while
evaluating expressions. */
bool stack_temporaries_enabled = false;
/* Values that are stored as temporaries on stack while evaluating
expressions. */
std::vector<struct value *> stack_temporaries;
/* Step-over chain. A thread is in the step-over queue if these are
non-NULL. If only a single thread is in the chain, then these
fields point to self. */
struct thread_info *step_over_prev = NULL;
struct thread_info *step_over_next = NULL;
};
/* A gdb::ref_ptr pointer to a thread_info. */
using thread_info_ref
= gdb::ref_ptr<struct thread_info, refcounted_object_ref_policy>;
/* Create an empty thread list, or empty the existing one. */
extern void init_thread_list (void);
/* Add a thread to the thread list, print a message
that a new thread is found, and return the pointer to
the new thread. Caller my use this pointer to
initialize the private thread data. */
extern struct thread_info *add_thread (ptid_t ptid);
/* Same as add_thread, but does not print a message
about new thread. */
extern struct thread_info *add_thread_silent (ptid_t ptid);
/* Same as add_thread, and sets the private info. */
extern struct thread_info *add_thread_with_info (ptid_t ptid,
struct private_thread_info *);
/* Delete an existing thread list entry. */
extern void delete_thread (struct thread_info *thread);
/* Delete an existing thread list entry, and be quiet about it. Used
after the process this thread having belonged to having already
exited, for example. */
extern void delete_thread_silent (struct thread_info *thread);
/* Delete a step_resume_breakpoint from the thread database. */
extern void delete_step_resume_breakpoint (struct thread_info *);
/* Delete an exception_resume_breakpoint from the thread database. */
extern void delete_exception_resume_breakpoint (struct thread_info *);
/* Delete the single-step breakpoints of thread TP, if any. */
extern void delete_single_step_breakpoints (struct thread_info *tp);
/* Check if the thread has software single stepping breakpoints
set. */
extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
/* Check whether the thread has software single stepping breakpoints
set at PC. */
extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
const address_space *aspace,
CORE_ADDR addr);
/* Returns whether to show inferior-qualified thread IDs, or plain
thread numbers. Inferior-qualified IDs are shown whenever we have
multiple inferiors, or the only inferior left has number > 1. */
extern int show_inferior_qualified_tids (void);
/* Return a string version of THR's thread ID. If there are multiple
inferiors, then this prints the inferior-qualifier form, otherwise
it only prints the thread number. The result is stored in a
circular static buffer, NUMCELLS deep. */
const char *print_thread_id (struct thread_info *thr);
/* Boolean test for an already-known ptid. */
extern int in_thread_list (ptid_t ptid);
/* Boolean test for an already-known global thread id (GDB's homegrown
global id, not the system's). */
extern int valid_global_thread_id (int global_id);
/* Search function to lookup a thread by 'pid'. */
extern struct thread_info *find_thread_ptid (ptid_t ptid);
/* Search function to lookup a thread by 'ptid'. Only searches in
threads of INF. */
extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
/* Find thread by GDB global thread ID. */
struct thread_info *find_thread_global_id (int global_id);
/* Find thread by thread library specific handle in inferior INF. */
struct thread_info *find_thread_by_handle (struct value *thread_handle,
struct inferior *inf);
/* Finds the first thread of the specified inferior. */
extern struct thread_info *first_thread_of_inferior (inferior *inf);
/* Returns any thread of inferior INF, giving preference to the
current thread. */
extern struct thread_info *any_thread_of_inferior (inferior *inf);
/* Returns any non-exited thread of inferior INF, giving preference to
the current thread, and to not executing threads. */
extern struct thread_info *any_live_thread_of_inferior (inferior *inf);
/* Change the ptid of thread OLD_PTID to NEW_PTID. */
void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid);
/* Iterator function to call a user-provided callback function
once for each known thread. */
typedef int (*thread_callback_func) (struct thread_info *, void *);
extern struct thread_info *iterate_over_threads (thread_callback_func, void *);
/* Pull in the internals of the inferiors/threads ranges and
iterators. Must be done after struct thread_info is defined. */
#include "thread-iter.h"
/* Return a range that can be used to walk over all threads of all
inferiors, with range-for. Used like this:
for (thread_info *thr : all_threads ())
{ .... }
*/
inline all_threads_range
all_threads ()
{
return {};
}
/* Likewise, but accept a filter PTID. */
inline all_matching_threads_range
all_threads (ptid_t filter_ptid)
{
return all_matching_threads_range (filter_ptid);
}
/* Return a range that can be used to walk over all non-exited threads
of all inferiors, with range-for. FILTER_PTID can be used to
filter out thread that don't match. */
inline all_non_exited_threads_range
all_non_exited_threads (ptid_t filter_ptid = minus_one_ptid)
{
return all_non_exited_threads_range (filter_ptid);
}
/* Return a range that can be used to walk over all threads of all
inferiors, with range-for, safely. I.e., it is safe to delete the
currently-iterated thread. When combined with range-for, this
allow convenient patterns like this:
for (thread_info *t : all_threads_safe ())
if (some_condition ())
delete f;
*/
inline all_threads_safe_range
all_threads_safe ()
{
return all_threads_safe_range ();
}
extern int thread_count (void);
/* Return true if we have any thread in any inferior. */
extern bool any_thread_p ();
/* Switch context to thread THR. Also sets the STOP_PC global. */
extern void switch_to_thread (struct thread_info *thr);
/* Switch context to no thread selected. */
extern void switch_to_no_thread ();
/* Switch from one thread to another. Does not read registers. */
extern void switch_to_thread_no_regs (struct thread_info *thread);
/* Marks or clears thread(s) PTID as resumed. If PTID is
MINUS_ONE_PTID, applies to all threads. If ptid_is_pid(PTID) is
true, applies to all threads of the process pointed at by PTID. */
extern void set_resumed (ptid_t ptid, int resumed);
/* Marks thread PTID is running, or stopped.
If PTID is minus_one_ptid, marks all threads. */
extern void set_running (ptid_t ptid, int running);
/* Marks or clears thread(s) PTID as having been requested to stop.
If PTID is MINUS_ONE_PTID, applies to all threads. If
ptid_is_pid(PTID) is true, applies to all threads of the process
pointed at by PTID. If STOP, then the THREAD_STOP_REQUESTED
observer is called with PTID as argument. */
extern void set_stop_requested (ptid_t ptid, int stop);
/* NOTE: Since the thread state is not a boolean, most times, you do
not want to check it with negation. If you really want to check if
the thread is stopped,
use (good):
if (is_stopped (ptid))
instead of (bad):
if (!is_running (ptid))
The latter also returns true on exited threads, most likelly not
what you want. */
/* Reports if in the frontend's perpective, thread PTID is running. */
extern int is_running (ptid_t ptid);
/* Is this thread listed, but known to have exited? We keep it listed
(but not visible) until it's safe to delete. */
extern int is_exited (ptid_t ptid);
/* In the frontend's perpective, is this thread stopped? */
extern int is_stopped (ptid_t ptid);
/* Marks thread PTID as executing, or not. If PTID is minus_one_ptid,
marks all threads.
Note that this is different from the running state. See the
description of state and executing fields of struct
thread_info. */
extern void set_executing (ptid_t ptid, int executing);
/* True if any (known or unknown) thread is or may be executing. */
extern int threads_are_executing (void);
/* Merge the executing property of thread PTID over to its thread
state property (frontend running/stopped view).
"not executing" -> "stopped"
"executing" -> "running"
"exited" -> "exited"
If PTID is minus_one_ptid, go over all threads.
Notifications are only emitted if the thread state did change. */
extern void finish_thread_state (ptid_t ptid);
/* Calls finish_thread_state on scope exit, unless release() is called
to disengage. */
class scoped_finish_thread_state
{
public:
explicit scoped_finish_thread_state (ptid_t ptid)
: m_ptid (ptid)
{}
~scoped_finish_thread_state ()
{
if (!m_released)
finish_thread_state (m_ptid);
}
/* Disengage. */
void release ()
{
m_released = true;
}
DISABLE_COPY_AND_ASSIGN (scoped_finish_thread_state);
private:
bool m_released = false;
ptid_t m_ptid;
};
/* Commands with a prefix of `thread'. */
extern struct cmd_list_element *thread_cmd_list;
extern void thread_command (const char *tidstr, int from_tty);
/* Print notices on thread events (attach, detach, etc.), set with
`set print thread-events'. */
extern int print_thread_events;
/* Prints the list of threads and their details on UIOUT. If
REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only
print threads whose ID is included in the list. If PID is not -1,
only print threads from the process PID. Otherwise, threads from
all attached PIDs are printed. If both REQUESTED_THREADS is not
NULL and PID is not -1, then the thread is printed if it belongs to
the specified process. Otherwise, an error is raised. */
extern void print_thread_info (struct ui_out *uiout, char *requested_threads,
int pid);
/* Save/restore current inferior/thread/frame. */
class scoped_restore_current_thread
{
public:
scoped_restore_current_thread ();
~scoped_restore_current_thread ();
DISABLE_COPY_AND_ASSIGN (scoped_restore_current_thread);
private:
/* Use the "class" keyword here, because of a clash with a "thread_info"
function in the Darwin API. */
class thread_info *m_thread;
inferior *m_inf;
frame_id m_selected_frame_id;
int m_selected_frame_level;
bool m_was_stopped;
};
/* Returns a pointer into the thread_info corresponding to
INFERIOR_PTID. INFERIOR_PTID *must* be in the thread list. */
extern struct thread_info* inferior_thread (void);
extern void update_thread_list (void);
/* Delete any thread the target says is no longer alive. */
extern void prune_threads (void);
/* Delete threads marked THREAD_EXITED. Unlike prune_threads, this
does not consult the target about whether the thread is alive right
now. */
extern void delete_exited_threads (void);
/* Return true if PC is in the stepping range of THREAD. */
int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread);
/* Enable storing stack temporaries for thread THR and disable and
clear the stack temporaries on destruction. Holds a strong
reference to THR. */
class enable_thread_stack_temporaries
{
public:
explicit enable_thread_stack_temporaries (struct thread_info *thr)
: m_thr (thr)
{
gdb_assert (m_thr != NULL);
m_thr->incref ();
m_thr->stack_temporaries_enabled = true;
m_thr->stack_temporaries.clear ();
}
~enable_thread_stack_temporaries ()
{
m_thr->stack_temporaries_enabled = false;
m_thr->stack_temporaries.clear ();
m_thr->decref ();
}
DISABLE_COPY_AND_ASSIGN (enable_thread_stack_temporaries);
private:
struct thread_info *m_thr;
};
extern bool thread_stack_temporaries_enabled_p (struct thread_info *tp);
extern void push_thread_stack_temporary (struct thread_info *tp, struct value *v);
extern value *get_last_thread_stack_temporary (struct thread_info *tp);
extern bool value_in_thread_stack_temporaries (struct value *,
struct thread_info *thr);
/* Add TP to the end of its inferior's pending step-over chain. */
extern void thread_step_over_chain_enqueue (struct thread_info *tp);
/* Remove TP from its inferior's pending step-over chain. */
extern void thread_step_over_chain_remove (struct thread_info *tp);
/* Return the next thread in the step-over chain starting at TP. NULL
if TP is the last entry in the chain. */
extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp);
/* Return true if TP is in the step-over chain. */
extern int thread_is_in_step_over_chain (struct thread_info *tp);
/* Cancel any ongoing execution command. */
extern void thread_cancel_execution_command (struct thread_info *thr);
/* Check whether it makes sense to access a register of the current
thread at this point. If not, throw an error (e.g., the thread is
executing). */
extern void validate_registers_access (void);
/* Check whether it makes sense to access a register of THREAD at this point.
Returns true if registers may be accessed; false otherwise. */
extern bool can_access_registers_thread (struct thread_info *thread);
/* Returns whether to show which thread hit the breakpoint, received a
signal, etc. and ended up causing a user-visible stop. This is
true iff we ever detected multiple threads. */
extern int show_thread_that_caused_stop (void);
/* Print the message for a thread or/and frame selected. */
extern void print_selected_thread_frame (struct ui_out *uiout,
user_selected_what selection);
/* Helper for the CLI's "thread" command and for MI's -thread-select.
Selects thread THR. TIDSTR is the original string the thread ID
was parsed from. This is used in the error message if THR is not
alive anymore. */
extern void thread_select (const char *tidstr, class thread_info *thr);
#endif /* GDBTHREAD_H */
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