mirrors/binutils-gdb
0
0
Fork 0
mirror of https://sourceware.org/git/binutils-gdb.git synced 2024-11-27 20:14:06 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity
afbe19f83a
binutils-gdb/gdb/infrun.h
Pedro Alves 4c2f2a792a Bail out of processing stop if hook-stop resumes target / changes context 
This patch, relative to a tree with
https://sourceware.org/ml/gdb-patches/2015-08/msg00295.html, fixes
issues/crashes that trigger if something unexpected happens during a
hook-stop.

E.g., if the inferior disappears while running the hook-stop, we hit
failed assertions:

 (gdb) define hook-stop
 Type commands for definition of "hook-stop".
 End with a line saying just "end".
 >kill
 >end
 (gdb) si
 Kill the program being debugged? (y or n) [answered Y; input not from terminal]
 /home/pedro/gdb/mygit/build/../src/gdb/thread.c:88: internal-error: inferior_thread: Assertion `tp' failed.
 A problem internal to GDB has been detected,
 further debugging may prove unreliable.
 Quit this debugging session? (y or n)

I noticed that if a hook-stop issues a synchronous execution command,
we print the same stop event twice:

 (gdb) define hook-stop
 Type commands for definition of "hook-stop".
 End with a line saying just "end".
 >si
 >end
 (gdb) si
 0x000000000040074a      42          args[i] = 1; /* Init value.  */  <<<<<<< once
 0x000000000040074a      42          args[i] = 1; /* Init value.  */  <<<<<<< twice
 (gdb)

In MI:

 *stopped,reason="end-stepping-range",frame={addr="0x000000000040074a",func="main",args=[],file="threads.c",fullname="/home/pedro/gdb/tests/threads.c",line="42"},thread-id="1",stopped-threads="all",core="0"
 *stopped,reason="end-stepping-range",frame={addr="0x000000000040074a",func="main",args=[],file="threads.c",fullname="/home/pedro/gdb/tests/threads.c",line="42"},thread-id="1",stopped-threads="all",core="0"
 (gdb)

The fix has GDB stop processing the event if the context changed.  I
don't expect people to be doing crazy things from the hook-stop.
E.g., it gives me headaches to try to come up a proper behavior for
handling a thread change from a hook-stop... (E.g., imagine the
hook-stop does thread N; step, with scheduler-locing on).  I think the
most important bit here is preventing crashes.

The patch adds a new hook-stop.exp test that covers the above and also
merges in the old hook-stop-continue.exp and hook-stop-frame.exp into
the same framework.

gdb/ChangeLog:
2015-09-14  Pedro Alves  <palves@redhat.com>

	* infrun.c (current_stop_id): New global.
	(get_stop_id, new_stop_id): New functions.
	(fetch_inferior_event): Handle normal_stop proceeding the target.
	(struct stop_context): New.
	(save_stop_context, release_stop_context_cleanup)
	(stop_context_changed): New functions.
	(normal_stop): Return true if the hook-stop changes the stop
	context.
	* infrun.h (get_stop_id): Declare.
	(normal_stop): Now returns int.  Add documentation.

gdb/testsuite/ChangeLog:
2015-09-14  Pedro Alves  <palves@redhat.com>

	* gdb.base/hook-stop-continue.c: Delete.
	* gdb.base/hook-stop-continue.exp: Delete.
	* gdb.base/hook-stop-frame.c: Delete.
	* gdb.base/hook-stop-frame.exp: Delete.
	* gdb.base/hook-stop.c: New file.
	* gdb.base/hook-stop.exp: New file.
2015-09-14 15:45:14 +01:00

234 lines
8.5 KiB
C
Raw Blame History

/* Copyright (C) 1986-2015 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/>. */
#ifndef INFRUN_H
#define INFRUN_H 1
#include "symtab.h"
struct target_waitstatus;
struct frame_info;
struct address_space;
struct return_value_info;
/* True if we are debugging run control. */
extern unsigned int debug_infrun;
/* True if we are debugging displaced stepping. */
extern int debug_displaced;
/* Nonzero if we want to give control to the user when we're notified
of shared library events by the dynamic linker. */
extern int stop_on_solib_events;
/* Are we simulating synchronous execution? This is used in async gdb
to implement the 'run', 'continue' etc commands, which will not
redisplay the prompt until the execution is actually over. */
extern int sync_execution;
/* True if execution commands resume all threads of all processes by
default; otherwise, resume only threads of the current inferior
process. */
extern int sched_multi;
/* When set, stop the 'step' command if we enter a function which has
no line number information. The normal behavior is that we step
over such function. */
extern int step_stop_if_no_debug;
/* If set, the inferior should be controlled in non-stop mode. In
this mode, each thread is controlled independently. Execution
commands apply only to the selected thread by default, and stop
events stop only the thread that had the event -- the other threads
are kept running freely. */
extern int non_stop;
/* When set (default), the target should attempt to disable the
operating system's address space randomization feature when
starting an inferior. */
extern int disable_randomization;
/* Returns a unique identifier for the current stop. This can be used
to tell whether a command has proceeded the inferior past the
current location. */
extern ULONGEST get_stop_id (void);
/* Reverse execution. */
enum exec_direction_kind
{
EXEC_FORWARD,
EXEC_REVERSE
};
/* The current execution direction. This should only be set to enum
exec_direction_kind values. It is only an int to make it
compatible with make_cleanup_restore_integer. */
extern int execution_direction;
extern void start_remote (int from_tty);
/* Clear out all variables saying what to do when inferior is
continued or stepped. First do this, then set the ones you want,
then call `proceed'. STEP indicates whether we're preparing for a
step/stepi command. */
extern void clear_proceed_status (int step);
extern void proceed (CORE_ADDR, enum gdb_signal);
/* The `resume' routine should only be called in special circumstances.
Normally, use `proceed', which handles a lot of bookkeeping. */
extern void resume (enum gdb_signal);
/* Return a ptid representing the set of threads that we will proceed,
in the perspective of the user/frontend. We may actually resume
fewer threads at first, e.g., if a thread is stopped at a
breakpoint that needs stepping-off, but that should not be visible
to the user/frontend, and neither should the frontend/user be
allowed to proceed any of the threads that happen to be stopped for
internal run control handling, if a previous command wanted them
resumed. */
extern ptid_t user_visible_resume_ptid (int step);
extern void wait_for_inferior (void);
/* Return control to GDB when the inferior stops for real. Print
appropriate messages, remove breakpoints, give terminal our modes,
and run the stop hook. Returns true if the stop hook proceeded the
target, false otherwise. */
extern int normal_stop (void);
extern void get_last_target_status (ptid_t *ptid,
struct target_waitstatus *status);
extern void prepare_for_detach (void);
extern void fetch_inferior_event (void *);
extern void init_wait_for_inferior (void);
extern void insert_step_resume_breakpoint_at_sal (struct gdbarch *,
struct symtab_and_line ,
struct frame_id);
/* Returns true if we're trying to step past the instruction at
ADDRESS in ASPACE. */
extern int stepping_past_instruction_at (struct address_space *aspace,
CORE_ADDR address);
/* Returns true if we're trying to step past an instruction that
triggers a non-steppable watchpoint. */
extern int stepping_past_nonsteppable_watchpoint (void);
extern void set_step_info (struct frame_info *frame,
struct symtab_and_line sal);
/* Several print_*_reason helper functions to print why the inferior
has stopped to the passed in UIOUT. */
/* Signal received, print why the inferior has stopped. */
extern void print_signal_received_reason (struct ui_out *uiout,
enum gdb_signal siggnal);
/* Print why the inferior has stopped. We are done with a
step/next/si/ni command, print why the inferior has stopped. */
extern void print_end_stepping_range_reason (struct ui_out *uiout);
/* The inferior was terminated by a signal, print why it stopped. */
extern void print_signal_exited_reason (struct ui_out *uiout,
enum gdb_signal siggnal);
/* The inferior program is finished, print why it stopped. */
extern void print_exited_reason (struct ui_out *uiout, int exitstatus);
/* Reverse execution: target ran out of history info, print why the
inferior has stopped. */
extern void print_no_history_reason (struct ui_out *uiout);
/* Print the result of a function at the end of a 'finish' command.
RV points at an object representing the captured return value/type
and its position in the value history. */
extern void print_return_value (struct ui_out *uiout,
struct return_value_info *rv);
/* Print current location without a level number, if we have changed
functions or hit a breakpoint. Print source line if we have one.
If the execution command captured a return value, print it. */
extern void print_stop_event (struct ui_out *uiout);
/* Pretty print the results of target_wait, for debugging purposes. */
extern void print_target_wait_results (ptid_t waiton_ptid, ptid_t result_ptid,
const struct target_waitstatus *ws);
extern int signal_stop_state (int);
extern int signal_print_state (int);
extern int signal_pass_state (int);
extern int signal_stop_update (int, int);
extern int signal_print_update (int, int);
extern int signal_pass_update (int, int);
extern void update_signals_program_target (void);
/* Clear the convenience variables associated with the exit of the
inferior. Currently, those variables are $_exitcode and
$_exitsignal. */
extern void clear_exit_convenience_vars (void);
/* Dump LEN bytes at BUF in hex to FILE, followed by a newline. */
extern void displaced_step_dump_bytes (struct ui_file *file,
const gdb_byte *buf, size_t len);
extern struct displaced_step_closure *get_displaced_step_closure_by_addr
(CORE_ADDR addr);
extern void update_observer_mode (void);
extern void signal_catch_update (const unsigned int *);
/* In some circumstances we allow a command to specify a numeric
signal. The idea is to keep these circumstances limited so that
users (and scripts) develop portable habits. For comparison,
POSIX.2 `kill' requires that 1,2,3,6,9,14, and 15 work (and using a
numeric signal at all is obsolescent. We are slightly more lenient
and allow 1-15 which should match host signal numbers on most
systems. Use of symbolic signal names is strongly encouraged. */
enum gdb_signal gdb_signal_from_command (int num);
/* Enables/disables infrun's async event source in the event loop. */
extern void infrun_async (int enable);
/* Call infrun's event handler the next time through the event
loop. */
extern void mark_infrun_async_event_handler (void);
/* The global queue of threads that need to do a step-over operation
to get past e.g., a breakpoint. */
extern struct thread_info *step_over_queue_head;
/* Remove breakpoints if possible (usually that means, if everything
is stopped). On failure, print a message. */
extern void maybe_remove_breakpoints (void);
#endif /* INFRUN_H */
Reference in New Issue View Git Blame Copy Permalink