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binutils-gdb/gdb/infrun.c
Andrew Cagney 0233186932 CARP: 
STEP_SKIPS_DELAY - add STEP_SKIPS_DELAY_P and rewrite use removing
  #ifdef's.
NO_SINGLE_STEP - replace with SOFTWARE_SINGLE_STEP_P +
  SOFTWARE_SINGLE_STEP.  Replace global variable one_stepped with static
  singlestep_breakpoints_inserted_p.  Cleanup infrun.c (scary!).
1998-11-27 23:35:08 +00:00

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/* Target-struct-independent code to start (run) and stop an inferior process.
Copyright 1986, 87, 88, 89, 91, 92, 93, 94, 95, 96, 97, 1998
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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "gdb_string.h"
#include <ctype.h>
#include "symtab.h"
#include "frame.h"
#include "inferior.h"
#include "breakpoint.h"
#include "wait.h"
#include "gdbcore.h"
#include "gdbcmd.h"
#include "target.h"
#include "gdbthread.h"
#include "annotate.h"
#include "symfile.h" /* for overlay functions */
#include <signal.h>
/* Prototypes for local functions */
static void signals_info PARAMS ((char *, int));
static void handle_command PARAMS ((char *, int));
static void sig_print_info PARAMS ((enum target_signal));
static void sig_print_header PARAMS ((void));
static void resume_cleanups PARAMS ((int));
static int hook_stop_stub PARAMS ((char *));
static void delete_breakpoint_current_contents PARAMS ((PTR));
void _initialize_infrun PARAMS ((void));
/* GET_LONGJMP_TARGET returns the PC at which longjmp() will resume the
program. It needs to examine the jmp_buf argument and extract the PC
from it. The return value is non-zero on success, zero otherwise. */
#ifndef GET_LONGJMP_TARGET
#define GET_LONGJMP_TARGET(PC_ADDR) 0
#endif
/* Some machines have trampoline code that sits between function callers
and the actual functions themselves. If this machine doesn't have
such things, disable their processing. */
#ifndef SKIP_TRAMPOLINE_CODE
#define SKIP_TRAMPOLINE_CODE(pc) 0
#endif
/* Dynamic function trampolines are similar to solib trampolines in that they
are between the caller and the callee. The difference is that when you
enter a dynamic trampoline, you can't determine the callee's address. Some
(usually complex) code needs to run in the dynamic trampoline to figure out
the callee's address. This macro is usually called twice. First, when we
enter the trampoline (looks like a normal function call at that point). It
should return the PC of a point within the trampoline where the callee's
address is known. Second, when we hit the breakpoint, this routine returns
the callee's address. At that point, things proceed as per a step resume
breakpoint. */
#ifndef DYNAMIC_TRAMPOLINE_NEXTPC
#define DYNAMIC_TRAMPOLINE_NEXTPC(pc) 0
#endif
/* On SVR4 based systems, determining the callee's address is exceedingly
difficult and depends on the implementation of the run time loader.
If we are stepping at the source level, we single step until we exit
the run time loader code and reach the callee's address. */
#ifndef IN_SOLIB_DYNSYM_RESOLVE_CODE
#define IN_SOLIB_DYNSYM_RESOLVE_CODE(pc) 0
#endif
/* For SVR4 shared libraries, each call goes through a small piece of
trampoline code in the ".plt" section. IN_SOLIB_CALL_TRAMPOLINE evaluates
to nonzero if we are current stopped in one of these. */
#ifndef IN_SOLIB_CALL_TRAMPOLINE
#define IN_SOLIB_CALL_TRAMPOLINE(pc,name) 0
#endif
/* In some shared library schemes, the return path from a shared library
call may need to go through a trampoline too. */
#ifndef IN_SOLIB_RETURN_TRAMPOLINE
#define IN_SOLIB_RETURN_TRAMPOLINE(pc,name) 0
#endif
/* On MIPS16, a function that returns a floating point value may call
a library helper function to copy the return value to a floating point
register. The IGNORE_HELPER_CALL macro returns non-zero if we
should ignore (i.e. step over) this function call. */
#ifndef IGNORE_HELPER_CALL
#define IGNORE_HELPER_CALL(pc) 0
#endif
/* On some systems, the PC may be left pointing at an instruction that won't
actually be executed. This is usually indicated by a bit in the PSW. If
we find ourselves in such a state, then we step the target beyond the
nullified instruction before returning control to the user so as to avoid
confusion. */
#ifndef INSTRUCTION_NULLIFIED
#define INSTRUCTION_NULLIFIED 0
#endif
/* Tables of how to react to signals; the user sets them. */
static unsigned char *signal_stop;
static unsigned char *signal_print;
static unsigned char *signal_program;
#define SET_SIGS(nsigs,sigs,flags) \
do { \
int signum = (nsigs); \
while (signum-- > 0) \
if ((sigs)[signum]) \
(flags)[signum] = 1; \
} while (0)
#define UNSET_SIGS(nsigs,sigs,flags) \
do { \
int signum = (nsigs); \
while (signum-- > 0) \
if ((sigs)[signum]) \
(flags)[signum] = 0; \
} while (0)
/* Command list pointer for the "stop" placeholder. */
static struct cmd_list_element *stop_command;
/* Nonzero if breakpoints are now inserted in the inferior. */
static int breakpoints_inserted;
/* Function inferior was in as of last step command. */
static struct symbol *step_start_function;
/* Nonzero if we are expecting a trace trap and should proceed from it. */
static int trap_expected;
#ifdef SOLIB_ADD
/* Nonzero if we want to give control to the user when we're notified
of shared library events by the dynamic linker. */
static int stop_on_solib_events;
#endif
#ifdef HP_OS_BUG
/* Nonzero if the next time we try to continue the inferior, it will
step one instruction and generate a spurious trace trap.
This is used to compensate for a bug in HP-UX. */
static int trap_expected_after_continue;
#endif
/* Nonzero means expecting a trace trap
and should stop the inferior and return silently when it happens. */
int stop_after_trap;
/* Nonzero means expecting a trap and caller will handle it themselves.
It is used after attach, due to attaching to a process;
when running in the shell before the child program has been exec'd;
and when running some kinds of remote stuff (FIXME?). */
int stop_soon_quietly;
/* Nonzero if proceed is being used for a "finish" command or a similar
situation when stop_registers should be saved. */
int proceed_to_finish;
/* Save register contents here when about to pop a stack dummy frame,
if-and-only-if proceed_to_finish is set.
Thus this contains the return value from the called function (assuming
values are returned in a register). */
char stop_registers[REGISTER_BYTES];
/* Nonzero if program stopped due to error trying to insert breakpoints. */
static int breakpoints_failed;
/* Nonzero after stop if current stack frame should be printed. */
static int stop_print_frame;
/* Non-zero if we just simulating a single-step. This is needed
because we cannot remove the breakpoints in the inferior process
until after the `wait' in `wait_for_inferior'. */
static int singlestep_breakpoints_inserted_p = 0;
/* Things to clean up if we QUIT out of resume (). */
/* ARGSUSED */
static void
resume_cleanups (arg)
int arg;
{
normal_stop ();
}
/* Resume the inferior, but allow a QUIT. This is useful if the user
wants to interrupt some lengthy single-stepping operation
(for child processes, the SIGINT goes to the inferior, and so
we get a SIGINT random_signal, but for remote debugging and perhaps
other targets, that's not true).
STEP nonzero if we should step (zero to continue instead).
SIG is the signal to give the inferior (zero for none). */
void
resume (step, sig)
int step;
enum target_signal sig;
{
struct cleanup *old_cleanups = make_cleanup ((make_cleanup_func)
resume_cleanups, 0);
QUIT;
#ifdef CANNOT_STEP_BREAKPOINT
/* Most targets can step a breakpoint instruction, thus executing it
normally. But if this one cannot, just continue and we will hit
it anyway. */
if (step && breakpoints_inserted && breakpoint_here_p (read_pc ()))
step = 0;
#endif
if (SOFTWARE_SINGLE_STEP_P && step)
{
/* Do it the hard way, w/temp breakpoints */
SOFTWARE_SINGLE_STEP (sig, 1 /*insert-breakpoints*/);
/* ...and don't ask hardware to do it. */
step = 0;
/* and do not pull these breakpoints until after a `wait' in
`wait_for_inferior' */
singlestep_breakpoints_inserted_p = 1;
}
/* Handle any optimized stores to the inferior NOW... */
#ifdef DO_DEFERRED_STORES
DO_DEFERRED_STORES;
#endif
/* Install inferior's terminal modes. */
target_terminal_inferior ();
target_resume (-1, step, sig);
discard_cleanups (old_cleanups);
}
/* Clear out all variables saying what to do when inferior is continued.
First do this, then set the ones you want, then call `proceed'. */
void
clear_proceed_status ()
{
trap_expected = 0;
step_range_start = 0;
step_range_end = 0;
step_frame_address = 0;
step_over_calls = -1;
stop_after_trap = 0;
stop_soon_quietly = 0;
proceed_to_finish = 0;
breakpoint_proceeded = 1; /* We're about to proceed... */
/* Discard any remaining commands or status from previous stop. */
bpstat_clear (&stop_bpstat);
}
/* Basic routine for continuing the program in various fashions.
ADDR is the address to resume at, or -1 for resume where stopped.
SIGGNAL is the signal to give it, or 0 for none,
or -1 for act according to how it stopped.
STEP is nonzero if should trap after one instruction.
-1 means return after that and print nothing.
You should probably set various step_... variables
before calling here, if you are stepping.
You should call clear_proceed_status before calling proceed. */
void
proceed (addr, siggnal, step)
CORE_ADDR addr;
enum target_signal siggnal;
int step;
{
int oneproc = 0;
if (step > 0)
step_start_function = find_pc_function (read_pc ());
if (step < 0)
stop_after_trap = 1;
if (addr == (CORE_ADDR)-1)
{
/* If there is a breakpoint at the address we will resume at,
step one instruction before inserting breakpoints
so that we do not stop right away. */
if (read_pc () == stop_pc && breakpoint_here_p (read_pc ()))
oneproc = 1;
#ifndef STEP_SKIPS_DELAY
#define STEP_SKIPS_DELAY(pc) (0)
#define STEP_SKIPS_DELAY_P (0)
#endif
/* Check breakpoint_here_p first, because breakpoint_here_p is fast
(it just checks internal GDB data structures) and STEP_SKIPS_DELAY
is slow (it needs to read memory from the target). */
if (STEP_SKIPS_DELAY_P
&& breakpoint_here_p (read_pc () + 4)
&& STEP_SKIPS_DELAY (read_pc ()))
oneproc = 1;
}
else
write_pc (addr);
#ifdef PREPARE_TO_PROCEED
/* In a multi-threaded task we may select another thread and then continue.
In this case the thread that stopped at a breakpoint will immediately
cause another stop, if it is not stepped over first. On the other hand,
if (ADDR != -1) we only want to single step over the breakpoint if we did
switch to another thread.
If we are single stepping, don't do any of the above.
(Note that in the current implementation single stepping another
thread after a breakpoint and then continuing will cause the original
breakpoint to be hit again, but you can always continue, so it's not
a big deal.) */
if (! step && PREPARE_TO_PROCEED (1) && breakpoint_here_p (read_pc ()))
oneproc = 1;
#endif /* PREPARE_TO_PROCEED */
#ifdef HP_OS_BUG
if (trap_expected_after_continue)
{
/* If (step == 0), a trap will be automatically generated after
the first instruction is executed. Force step one
instruction to clear this condition. This should not occur
if step is nonzero, but it is harmless in that case. */
oneproc = 1;
trap_expected_after_continue = 0;
}
#endif /* HP_OS_BUG */
if (oneproc)
/* We will get a trace trap after one instruction.
Continue it automatically and insert breakpoints then. */
trap_expected = 1;
else
{
int temp = insert_breakpoints ();
if (temp)
{
print_sys_errmsg ("ptrace", temp);
error ("Cannot insert breakpoints.\n\
The same program may be running in another process.");
}
breakpoints_inserted = 1;
}
if (siggnal != TARGET_SIGNAL_DEFAULT)
stop_signal = siggnal;
/* If this signal should not be seen by program,
give it zero. Used for debugging signals. */
else if (!signal_program[stop_signal])
stop_signal = TARGET_SIGNAL_0;
annotate_starting ();
/* Make sure that output from GDB appears before output from the
inferior. */
gdb_flush (gdb_stdout);
/* Resume inferior. */
resume (oneproc || step || bpstat_should_step (), stop_signal);
/* Wait for it to stop (if not standalone)
and in any case decode why it stopped, and act accordingly. */
wait_for_inferior ();
normal_stop ();
}
/* Record the pc and sp of the program the last time it stopped.
These are just used internally by wait_for_inferior, but need
to be preserved over calls to it and cleared when the inferior
is started. */
static CORE_ADDR prev_pc;
static CORE_ADDR prev_func_start;
static char *prev_func_name;
/* Start remote-debugging of a machine over a serial link. */
void
start_remote ()
{
init_thread_list ();
init_wait_for_inferior ();
clear_proceed_status ();
stop_soon_quietly = 1;
trap_expected = 0;
wait_for_inferior ();
normal_stop ();
}
/* Initialize static vars when a new inferior begins. */
void
init_wait_for_inferior ()
{
/* These are meaningless until the first time through wait_for_inferior. */
prev_pc = 0;
prev_func_start = 0;
prev_func_name = NULL;
#ifdef HP_OS_BUG
trap_expected_after_continue = 0;
#endif
breakpoints_inserted = 0;
breakpoint_init_inferior ();
/* Don't confuse first call to proceed(). */
stop_signal = TARGET_SIGNAL_0;
}
static void
delete_breakpoint_current_contents (arg)
PTR arg;
{
struct breakpoint **breakpointp = (struct breakpoint **)arg;
if (*breakpointp != NULL)
delete_breakpoint (*breakpointp);
}
/* Wait for control to return from inferior to debugger.
If inferior gets a signal, we may decide to start it up again
instead of returning. That is why there is a loop in this function.
When this function actually returns it means the inferior
should be left stopped and GDB should read more commands. */
void
wait_for_inferior ()
{
struct cleanup *old_cleanups;
struct target_waitstatus w;
int another_trap;
int random_signal = 0;
CORE_ADDR stop_func_start;
CORE_ADDR stop_func_end;
char *stop_func_name;
#if 0
CORE_ADDR prologue_pc = 0;
#endif
CORE_ADDR tmp;
struct symtab_and_line sal;
int remove_breakpoints_on_following_step = 0;
int current_line;
struct symtab *current_symtab;
int handling_longjmp = 0; /* FIXME */
struct breakpoint *step_resume_breakpoint = NULL;
struct breakpoint *through_sigtramp_breakpoint = NULL;
int pid;
int update_step_sp = 0;
old_cleanups = make_cleanup (delete_breakpoint_current_contents,
&step_resume_breakpoint);
make_cleanup (delete_breakpoint_current_contents,
&through_sigtramp_breakpoint);
sal = find_pc_line(prev_pc, 0);
current_line = sal.line;
current_symtab = sal.symtab;
/* Are we stepping? */
#define CURRENTLY_STEPPING() \
((through_sigtramp_breakpoint == NULL \
&& !handling_longjmp \
&& ((step_range_end && step_resume_breakpoint == NULL) \
|| trap_expected)) \
|| bpstat_should_step ())
while (1)
{
extern int overlay_cache_invalid; /* declared in symfile.h */
overlay_cache_invalid = 1;
/* We have to invalidate the registers BEFORE calling target_wait because
they can be loaded from the target while in target_wait. This makes
remote debugging a bit more efficient for those targets that provide
critical registers as part of their normal status mechanism. */
registers_changed ();
if (target_wait_hook)
pid = target_wait_hook (-1, &w);
else
pid = target_wait (-1, &w);
/* Gross.
We goto this label from elsewhere in wait_for_inferior when we want
to continue the main loop without calling "wait" and trashing the
waitstatus contained in W. */
have_waited:
flush_cached_frames ();
/* If it's a new process, add it to the thread database */
if (w.kind != TARGET_WAITKIND_EXITED
&& w.kind != TARGET_WAITKIND_SIGNALLED
&& pid != inferior_pid
&& !in_thread_list (pid))
{
add_thread (pid);
printf_filtered ("[New %s]\n", target_pid_to_str (pid));
/* We may want to consider not doing a resume here in order to give
the user a chance to play with the new thread. It might be good
to make that a user-settable option. */
/* At this point, all threads are stopped (happens automatically in
either the OS or the native code). Therefore we need to continue
all threads in order to make progress. */
target_resume (-1, 0, TARGET_SIGNAL_0);
continue;
}
switch (w.kind)
{
case TARGET_WAITKIND_LOADED:
/* Ignore gracefully during startup of the inferior, as it
might be the shell which has just loaded some objects,
otherwise add the symbols for the newly loaded objects. */
#ifdef SOLIB_ADD
if (!stop_soon_quietly)
{
extern int auto_solib_add;
/* Remove breakpoints, SOLIB_ADD might adjust
breakpoint addresses via breakpoint_re_set. */
if (breakpoints_inserted)
remove_breakpoints ();
/* Check for any newly added shared libraries if we're
supposed to be adding them automatically. */
if (auto_solib_add)
{
/* Switch terminal for any messages produced by
breakpoint_re_set. */
target_terminal_ours_for_output ();
SOLIB_ADD (NULL, 0, NULL);
target_terminal_inferior ();
}
/* Reinsert breakpoints and continue. */
if (breakpoints_inserted)
insert_breakpoints ();
}
#endif
resume (0, TARGET_SIGNAL_0);
continue;
case TARGET_WAITKIND_SPURIOUS:
resume (0, TARGET_SIGNAL_0);
continue;
case TARGET_WAITKIND_EXITED:
target_terminal_ours (); /* Must do this before mourn anyway */
annotate_exited (w.value.integer);
if (w.value.integer)
printf_filtered ("\nProgram exited with code 0%o.\n",
(unsigned int)w.value.integer);
else
printf_filtered ("\nProgram exited normally.\n");
/* Record the exit code in the convenience variable $_exitcode, so
that the user can inspect this again later. */
set_internalvar (lookup_internalvar ("_exitcode"),
value_from_longest (builtin_type_int,
(LONGEST) w.value.integer));
gdb_flush (gdb_stdout);
target_mourn_inferior ();
singlestep_breakpoints_inserted_p = 0; /*SOFTWARE_SINGLE_STEP_P*/
stop_print_frame = 0;
goto stop_stepping;
case TARGET_WAITKIND_SIGNALLED:
stop_print_frame = 0;
stop_signal = w.value.sig;
target_terminal_ours (); /* Must do this before mourn anyway */
annotate_signalled ();
/* This looks pretty bogus to me. Doesn't TARGET_WAITKIND_SIGNALLED
mean it is already dead? This has been here since GDB 2.8, so
perhaps it means rms didn't understand unix waitstatuses?
For the moment I'm just kludging around this in remote.c
rather than trying to change it here --kingdon, 5 Dec 1994. */
target_kill (); /* kill mourns as well */
printf_filtered ("\nProgram terminated with signal ");
annotate_signal_name ();
printf_filtered ("%s", target_signal_to_name (stop_signal));
annotate_signal_name_end ();
printf_filtered (", ");
annotate_signal_string ();
printf_filtered ("%s", target_signal_to_string (stop_signal));
annotate_signal_string_end ();
printf_filtered (".\n");
printf_filtered ("The program no longer exists.\n");
gdb_flush (gdb_stdout);
singlestep_breakpoints_inserted_p = 0; /*SOFTWARE_SINGLE_STEP_P*/
goto stop_stepping;
case TARGET_WAITKIND_STOPPED:
/* This is the only case in which we keep going; the above cases
end in a continue or goto. */
break;
}
stop_signal = w.value.sig;
stop_pc = read_pc_pid (pid);
/* See if a thread hit a thread-specific breakpoint that was meant for
another thread. If so, then step that thread past the breakpoint,
and continue it. */
if (stop_signal == TARGET_SIGNAL_TRAP)
{
if (SOFTWARE_SINGLE_STEP_P && singlestep_breakpoints_inserted_p)
random_signal = 0;
else
if (breakpoints_inserted
&& breakpoint_here_p (stop_pc - DECR_PC_AFTER_BREAK))
{
random_signal = 0;
if (!breakpoint_thread_match (stop_pc - DECR_PC_AFTER_BREAK, pid))
{
/* Saw a breakpoint, but it was hit by the wrong thread. Just continue. */
write_pc_pid (stop_pc - DECR_PC_AFTER_BREAK, pid);
remove_breakpoints ();
target_resume (pid, 1, TARGET_SIGNAL_0); /* Single step */
/* FIXME: What if a signal arrives instead of the single-step
happening? */
if (target_wait_hook)
target_wait_hook (pid, &w);
else
target_wait (pid, &w);
insert_breakpoints ();
/* We need to restart all the threads now. */
target_resume (-1, 0, TARGET_SIGNAL_0);
continue;
}
}
}
else
random_signal = 1;
/* See if something interesting happened to the non-current thread. If
so, then switch to that thread, and eventually give control back to
the user. */
if (pid != inferior_pid)
{
int printed = 0;
/* If it's a random signal for a non-current thread, notify user
if he's expressed an interest. */
if (random_signal
&& signal_print[stop_signal])
{
printed = 1;
target_terminal_ours_for_output ();
printf_filtered ("\nProgram received signal %s, %s.\n",
target_signal_to_name (stop_signal),
target_signal_to_string (stop_signal));
gdb_flush (gdb_stdout);
}
/* If it's not SIGTRAP and not a signal we want to stop for, then
continue the thread. */
if (stop_signal != TARGET_SIGNAL_TRAP
&& !signal_stop[stop_signal])
{
if (printed)
target_terminal_inferior ();
/* Clear the signal if it should not be passed. */
if (signal_program[stop_signal] == 0)
stop_signal = TARGET_SIGNAL_0;
target_resume (pid, 0, stop_signal);
continue;
}
/* It's a SIGTRAP or a signal we're interested in. Switch threads,
and fall into the rest of wait_for_inferior(). */
/* Save infrun state for the old thread. */
save_infrun_state (inferior_pid, prev_pc,
prev_func_start, prev_func_name,
trap_expected, step_resume_breakpoint,
through_sigtramp_breakpoint,
step_range_start, step_range_end,
step_frame_address, handling_longjmp,
another_trap);
inferior_pid = pid;
/* Load infrun state for the new thread. */
load_infrun_state (inferior_pid, &prev_pc,
&prev_func_start, &prev_func_name,
&trap_expected, &step_resume_breakpoint,
&through_sigtramp_breakpoint,
&step_range_start, &step_range_end,
&step_frame_address, &handling_longjmp,
&another_trap);
if (context_hook)
context_hook (pid_to_thread_id (pid));
printf_filtered ("[Switching to %s]\n", target_pid_to_str (pid));
flush_cached_frames ();
}
if (SOFTWARE_SINGLE_STEP_P && singlestep_breakpoints_inserted_p)
{
/* Pull the single step breakpoints out of the target. */
SOFTWARE_SINGLE_STEP (0, 0);
singlestep_breakpoints_inserted_p = 0;
}
/* If PC is pointing at a nullified instruction, then step beyond
it so that the user won't be confused when GDB appears to be ready
to execute it. */
if (INSTRUCTION_NULLIFIED)
{
struct target_waitstatus tmpstatus;
registers_changed ();
target_resume (pid, 1, TARGET_SIGNAL_0);
/* We may have received a signal that we want to pass to
the inferior; therefore, we must not clobber the waitstatus
in W. So we call wait ourselves, then continue the loop
at the "have_waited" label. */
if (target_wait_hook)
target_wait_hook (pid, &tmpstatus);
else
target_wait (pid, &tmpstatus);
goto have_waited;
}
#ifdef HAVE_STEPPABLE_WATCHPOINT
/* It may not be necessary to disable the watchpoint to stop over
it. For example, the PA can (with some kernel cooperation)
single step over a watchpoint without disabling the watchpoint. */
if (STOPPED_BY_WATCHPOINT (w))
{
resume (1, 0);
continue;
}
#endif
#ifdef HAVE_NONSTEPPABLE_WATCHPOINT
/* It is far more common to need to disable a watchpoint
to step the inferior over it. FIXME. What else might
a debug register or page protection watchpoint scheme need
here? */
if (STOPPED_BY_WATCHPOINT (w))
{
/* At this point, we are stopped at an instruction which has attempted to write
to a piece of memory under control of a watchpoint. The instruction hasn't
actually executed yet. If we were to evaluate the watchpoint expression
now, we would get the old value, and therefore no change would seem to have
occurred.
In order to make watchpoints work `right', we really need to complete the
memory write, and then evaluate the watchpoint expression. The following
code does that by removing the watchpoint (actually, all watchpoints and
breakpoints), single-stepping the target, re-inserting watchpoints, and then
falling through to let normal single-step processing handle proceed. Since
this includes evaluating watchpoints, things will come to a stop in the
correct manner. */
write_pc (stop_pc - DECR_PC_AFTER_BREAK);
remove_breakpoints ();
registers_changed();
target_resume (pid, 1, TARGET_SIGNAL_0); /* Single step */
if (target_wait_hook)
target_wait_hook (pid, &w);
else
target_wait (pid, &w);
insert_breakpoints ();
/* FIXME-maybe: is this cleaner than setting a flag? Does it
handle things like signals arriving and other things happening
in combination correctly? */
goto have_waited;
}
#endif
#ifdef HAVE_CONTINUABLE_WATCHPOINT
/* It may be possible to simply continue after a watchpoint. */
STOPPED_BY_WATCHPOINT (w);
#endif
stop_func_start = 0;
stop_func_end = 0;
stop_func_name = 0;
/* Don't care about return value; stop_func_start and stop_func_name
will both be 0 if it doesn't work. */
find_pc_partial_function (stop_pc, &stop_func_name, &stop_func_start,
&stop_func_end);
stop_func_start += FUNCTION_START_OFFSET;
another_trap = 0;
bpstat_clear (&stop_bpstat);
stop_step = 0;
stop_stack_dummy = 0;
stop_print_frame = 1;
random_signal = 0;
stopped_by_random_signal = 0;
breakpoints_failed = 0;
/* Look at the cause of the stop, and decide what to do.
The alternatives are:
1) break; to really stop and return to the debugger,
2) drop through to start up again
(set another_trap to 1 to single step once)
3) set random_signal to 1, and the decision between 1 and 2
will be made according to the signal handling tables. */
/* First, distinguish signals caused by the debugger from signals
that have to do with the program's own actions.
Note that breakpoint insns may cause SIGTRAP or SIGILL
or SIGEMT, depending on the operating system version.
Here we detect when a SIGILL or SIGEMT is really a breakpoint
and change it to SIGTRAP. */
if (stop_signal == TARGET_SIGNAL_TRAP
|| (breakpoints_inserted &&
(stop_signal == TARGET_SIGNAL_ILL
|| stop_signal == TARGET_SIGNAL_EMT
))
|| stop_soon_quietly)
{
if (stop_signal == TARGET_SIGNAL_TRAP && stop_after_trap)
{
stop_print_frame = 0;
break;
}
if (stop_soon_quietly)
break;
/* Don't even think about breakpoints
if just proceeded over a breakpoint.
However, if we are trying to proceed over a breakpoint
and end up in sigtramp, then through_sigtramp_breakpoint
will be set and we should check whether we've hit the
step breakpoint. */
if (stop_signal == TARGET_SIGNAL_TRAP && trap_expected
&& through_sigtramp_breakpoint == NULL)
bpstat_clear (&stop_bpstat);
else
{
/* See if there is a breakpoint at the current PC. */
stop_bpstat = bpstat_stop_status
(&stop_pc,
(DECR_PC_AFTER_BREAK ?
/* Notice the case of stepping through a jump
that lands just after a breakpoint.
Don't confuse that with hitting the breakpoint.
What we check for is that 1) stepping is going on
and 2) the pc before the last insn does not match
the address of the breakpoint before the current pc
and 3) we didn't hit a breakpoint in a signal handler
without an intervening stop in sigtramp, which is
detected by a new stack pointer value below
any usual function calling stack adjustments. */
(CURRENTLY_STEPPING ()
&& prev_pc != stop_pc - DECR_PC_AFTER_BREAK
&& !(step_range_end
&& read_sp () INNER_THAN (step_sp - 16))) :
0)
);
/* Following in case break condition called a
function. */
stop_print_frame = 1;
}
if (stop_signal == TARGET_SIGNAL_TRAP)
random_signal
= !(bpstat_explains_signal (stop_bpstat)
|| trap_expected
#ifndef CALL_DUMMY_BREAKPOINT_OFFSET
|| PC_IN_CALL_DUMMY (stop_pc, read_sp (),
FRAME_FP (get_current_frame ()))
#endif /* No CALL_DUMMY_BREAKPOINT_OFFSET. */
|| (step_range_end && step_resume_breakpoint == NULL));
else
{
random_signal
= !(bpstat_explains_signal (stop_bpstat)
/* End of a stack dummy. Some systems (e.g. Sony
news) give another signal besides SIGTRAP,
so check here as well as above. */
#ifndef CALL_DUMMY_BREAKPOINT_OFFSET
|| PC_IN_CALL_DUMMY (stop_pc, read_sp (),
FRAME_FP (get_current_frame ()))
#endif /* No CALL_DUMMY_BREAKPOINT_OFFSET. */
);
if (!random_signal)
stop_signal = TARGET_SIGNAL_TRAP;
}
}
else
random_signal = 1;
/* For the program's own signals, act according to
the signal handling tables. */
if (random_signal)
{
/* Signal not for debugging purposes. */
int printed = 0;
stopped_by_random_signal = 1;
if (signal_print[stop_signal])
{
printed = 1;
target_terminal_ours_for_output ();
annotate_signal ();
printf_filtered ("\nProgram received signal ");
annotate_signal_name ();
printf_filtered ("%s", target_signal_to_name (stop_signal));
annotate_signal_name_end ();
printf_filtered (", ");
annotate_signal_string ();
printf_filtered ("%s", target_signal_to_string (stop_signal));
annotate_signal_string_end ();
printf_filtered (".\n");
gdb_flush (gdb_stdout);
}
if (signal_stop[stop_signal])
break;
/* If not going to stop, give terminal back
if we took it away. */
else if (printed)
target_terminal_inferior ();
/* Clear the signal if it should not be passed. */
if (signal_program[stop_signal] == 0)
stop_signal = TARGET_SIGNAL_0;
/* I'm not sure whether this needs to be check_sigtramp2 or
whether it could/should be keep_going. */
goto check_sigtramp2;
}
/* Handle cases caused by hitting a breakpoint. */
{
CORE_ADDR jmp_buf_pc;
struct bpstat_what what;
what = bpstat_what (stop_bpstat);
if (what.call_dummy)
{
stop_stack_dummy = 1;
#ifdef HP_OS_BUG
trap_expected_after_continue = 1;
#endif
}
switch (what.main_action)
{
case BPSTAT_WHAT_SET_LONGJMP_RESUME:
/* If we hit the breakpoint at longjmp, disable it for the
duration of this command. Then, install a temporary
breakpoint at the target of the jmp_buf. */
disable_longjmp_breakpoint();
remove_breakpoints ();
breakpoints_inserted = 0;
if (!GET_LONGJMP_TARGET(&jmp_buf_pc)) goto keep_going;
/* Need to blow away step-resume breakpoint, as it
interferes with us */
if (step_resume_breakpoint != NULL)
{
delete_breakpoint (step_resume_breakpoint);
step_resume_breakpoint = NULL;
}
/* Not sure whether we need to blow this away too, but probably
it is like the step-resume breakpoint. */
if (through_sigtramp_breakpoint != NULL)
{
delete_breakpoint (through_sigtramp_breakpoint);
through_sigtramp_breakpoint = NULL;
}
#if 0
/* FIXME - Need to implement nested temporary breakpoints */
if (step_over_calls > 0)
set_longjmp_resume_breakpoint(jmp_buf_pc,
get_current_frame());
else
#endif /* 0 */
set_longjmp_resume_breakpoint(jmp_buf_pc, NULL);
handling_longjmp = 1; /* FIXME */
goto keep_going;
case BPSTAT_WHAT_CLEAR_LONGJMP_RESUME:
case BPSTAT_WHAT_CLEAR_LONGJMP_RESUME_SINGLE:
remove_breakpoints ();
breakpoints_inserted = 0;
#if 0
/* FIXME - Need to implement nested temporary breakpoints */
if (step_over_calls
&& (FRAME_FP (get_current_frame ())
INNER_THAN step_frame_address))
{
another_trap = 1;
goto keep_going;
}
#endif /* 0 */
disable_longjmp_breakpoint();
handling_longjmp = 0; /* FIXME */
if (what.main_action == BPSTAT_WHAT_CLEAR_LONGJMP_RESUME)
break;
/* else fallthrough */
case BPSTAT_WHAT_SINGLE:
if (breakpoints_inserted)
remove_breakpoints ();
breakpoints_inserted = 0;
another_trap = 1;
/* Still need to check other stuff, at least the case
where we are stepping and step out of the right range. */
break;
case BPSTAT_WHAT_STOP_NOISY:
stop_print_frame = 1;
/* We are about to nuke the step_resume_breakpoint and
through_sigtramp_breakpoint via the cleanup chain, so
no need to worry about it here. */
goto stop_stepping;
case BPSTAT_WHAT_STOP_SILENT:
stop_print_frame = 0;
/* We are about to nuke the step_resume_breakpoint and
through_sigtramp_breakpoint via the cleanup chain, so
no need to worry about it here. */
goto stop_stepping;
case BPSTAT_WHAT_STEP_RESUME:
delete_breakpoint (step_resume_breakpoint);
step_resume_breakpoint = NULL;
break;
case BPSTAT_WHAT_THROUGH_SIGTRAMP:
if (through_sigtramp_breakpoint)
delete_breakpoint (through_sigtramp_breakpoint);
through_sigtramp_breakpoint = NULL;
/* If were waiting for a trap, hitting the step_resume_break
doesn't count as getting it. */
if (trap_expected)
another_trap = 1;
break;
case BPSTAT_WHAT_CHECK_SHLIBS:
#ifdef SOLIB_ADD
{
extern int auto_solib_add;
/* Remove breakpoints, we eventually want to step over the
shlib event breakpoint, and SOLIB_ADD might adjust
breakpoint addresses via breakpoint_re_set. */
if (breakpoints_inserted)
remove_breakpoints ();
breakpoints_inserted = 0;
/* Check for any newly added shared libraries if we're
supposed to be adding them automatically. */
if (auto_solib_add)
{
/* Switch terminal for any messages produced by
breakpoint_re_set. */
target_terminal_ours_for_output ();
SOLIB_ADD (NULL, 0, NULL);
target_terminal_inferior ();
}
/* Try to reenable shared library breakpoints, additional
code segments in shared libraries might be mapped in now. */
re_enable_breakpoints_in_shlibs ();
/* If requested, stop when the dynamic linker notifies
gdb of events. This allows the user to get control
and place breakpoints in initializer routines for
dynamically loaded objects (among other things). */
if (stop_on_solib_events)
{
stop_print_frame = 0;
goto stop_stepping;
}
else
{
/* We want to step over this breakpoint, then keep going. */
another_trap = 1;
break;
}
}
#endif
break;
case BPSTAT_WHAT_LAST:
/* Not a real code, but listed here to shut up gcc -Wall. */
case BPSTAT_WHAT_KEEP_CHECKING:
break;
}
}
/* We come here if we hit a breakpoint but should not
stop for it. Possibly we also were stepping
and should stop for that. So fall through and
test for stepping. But, if not stepping,
do not stop. */
#ifndef CALL_DUMMY_BREAKPOINT_OFFSET
/* This is the old way of detecting the end of the stack dummy.
An architecture which defines CALL_DUMMY_BREAKPOINT_OFFSET gets
handled above. As soon as we can test it on all of them, all
architectures should define it. */
/* If this is the breakpoint at the end of a stack dummy,
just stop silently, unless the user was doing an si/ni, in which
case she'd better know what she's doing. */
if (PC_IN_CALL_DUMMY (stop_pc, read_sp (), FRAME_FP (get_current_frame ()))
&& !step_range_end)
{
stop_print_frame = 0;
stop_stack_dummy = 1;
#ifdef HP_OS_BUG
trap_expected_after_continue = 1;
#endif
break;
}
#endif /* No CALL_DUMMY_BREAKPOINT_OFFSET. */
if (step_resume_breakpoint)
/* Having a step-resume breakpoint overrides anything
else having to do with stepping commands until
that breakpoint is reached. */
/* I'm not sure whether this needs to be check_sigtramp2 or
whether it could/should be keep_going. */
goto check_sigtramp2;
if (step_range_end == 0)
/* Likewise if we aren't even stepping. */
/* I'm not sure whether this needs to be check_sigtramp2 or
whether it could/should be keep_going. */
goto check_sigtramp2;
/* If stepping through a line, keep going if still within it. */
if (stop_pc >= step_range_start
&& stop_pc < step_range_end
#if 0
/* I haven't a clue what might trigger this clause, and it seems wrong anyway,
so I've disabled it until someone complains. -Stu 10/24/95 */
/* The step range might include the start of the
function, so if we are at the start of the
step range and either the stack or frame pointers
just changed, we've stepped outside */
&& !(stop_pc == step_range_start
&& FRAME_FP (get_current_frame ())
&& (read_sp () INNER_THAN step_sp
|| FRAME_FP (get_current_frame ()) != step_frame_address))
#endif
)
{
/* We might be doing a BPSTAT_WHAT_SINGLE and getting a signal.
So definately need to check for sigtramp here. */
goto check_sigtramp2;
}
/* We stepped out of the stepping range. */
/* If we are stepping at the source level and entered the runtime
loader dynamic symbol resolution code, we keep on single stepping
until we exit the run time loader code and reach the callee's
address. */
if (step_over_calls < 0 && IN_SOLIB_DYNSYM_RESOLVE_CODE (stop_pc))
goto keep_going;
/* We can't update step_sp every time through the loop, because
reading the stack pointer would slow down stepping too much.
But we can update it every time we leave the step range. */
update_step_sp = 1;
/* Did we just take a signal? */
if (IN_SIGTRAMP (stop_pc, stop_func_name)
&& !IN_SIGTRAMP (prev_pc, prev_func_name)
&& read_sp () INNER_THAN step_sp)
{
/* We've just taken a signal; go until we are back to
the point where we took it and one more. */
/* This code is needed at least in the following case:
The user types "next" and then a signal arrives (before
the "next" is done). */
/* Note that if we are stopped at a breakpoint, then we need
the step_resume breakpoint to override any breakpoints at
the same location, so that we will still step over the
breakpoint even though the signal happened. */
{
struct symtab_and_line sr_sal;
INIT_SAL (&sr_sal); /* initialize to zeroes */
sr_sal.pc = prev_pc;
sr_sal.section = find_pc_overlay (sr_sal.pc);
/* We could probably be setting the frame to
step_frame_address; I don't think anyone thought to try it. */
step_resume_breakpoint =
set_momentary_breakpoint (sr_sal, NULL, bp_step_resume);
if (breakpoints_inserted)
insert_breakpoints ();
}
/* If this is stepi or nexti, make sure that the stepping range
gets us past that instruction. */
if (step_range_end == 1)
/* FIXME: Does this run afoul of the code below which, if
we step into the middle of a line, resets the stepping
range? */
step_range_end = (step_range_start = prev_pc) + 1;
remove_breakpoints_on_following_step = 1;
goto keep_going;
}
#if 0
/* I disabled this test because it was too complicated and slow. The
SKIP_PROLOGUE was especially slow, because it caused unnecessary
prologue examination on various architectures. The code in the #else
clause has been tested on the Sparc, Mips, PA, and Power
architectures, so it's pretty likely to be correct. -Stu 10/24/95 */
/* See if we left the step range due to a subroutine call that
we should proceed to the end of. */
if (stop_func_start)
{
struct symtab *s;
/* Do this after the IN_SIGTRAMP check; it might give
an error. */
prologue_pc = stop_func_start;
/* Don't skip the prologue if this is assembly source */
s = find_pc_symtab (stop_pc);
if (s && s->language != language_asm)
SKIP_PROLOGUE (prologue_pc);
}
if (!(step_sp INNER_THAN read_sp ()) /* don't mistake (sig)return as a call */
&& (/* Might be a non-recursive call. If the symbols are missing
enough that stop_func_start == prev_func_start even though
they are really two functions, we will treat some calls as
jumps. */
stop_func_start != prev_func_start
/* Might be a recursive call if either we have a prologue
or the call instruction itself saves the PC on the stack. */
|| prologue_pc != stop_func_start
|| read_sp () != step_sp)
&& (/* PC is completely out of bounds of any known objfiles. Treat
like a subroutine call. */
! stop_func_start
/* If we do a call, we will be at the start of a function... */
|| stop_pc == stop_func_start
/* ...except on the Alpha with -O (and also Irix 5 and
perhaps others), in which we might call the address
after the load of gp. Since prologues don't contain
calls, we can't return to within one, and we don't
jump back into them, so this check is OK. */
|| stop_pc < prologue_pc
/* ...and if it is a leaf function, the prologue might
consist of gp loading only, so the call transfers to
the first instruction after the prologue. */
|| (stop_pc == prologue_pc
/* Distinguish this from the case where we jump back
to the first instruction after the prologue,
within a function. */
&& stop_func_start != prev_func_start)
/* If we end up in certain places, it means we did a subroutine
call. I'm not completely sure this is necessary now that we
have the above checks with stop_func_start (and now that
find_pc_partial_function is pickier). */
|| IN_SOLIB_CALL_TRAMPOLINE (stop_pc, stop_func_name)
/* If none of the above apply, it is a jump within a function,
or a return from a subroutine. The other case is longjmp,
which can no longer happen here as long as the
handling_longjmp stuff is working. */
))
#else
/* This test is a much more streamlined, (but hopefully correct)
replacement for the code above. It's been tested on the Sparc,
Mips, PA, and Power architectures with good results. */
if (stop_pc == stop_func_start /* Quick test */
|| in_prologue (stop_pc, stop_func_start)
|| IN_SOLIB_CALL_TRAMPOLINE (stop_pc, stop_func_name)
|| stop_func_name == 0)
#endif
{
/* It's a subroutine call. */
if (step_over_calls == 0)
{
/* I presume that step_over_calls is only 0 when we're
supposed to be stepping at the assembly language level
("stepi"). Just stop. */
stop_step = 1;
break;
}
if (step_over_calls > 0 || IGNORE_HELPER_CALL (stop_pc))
/* We're doing a "next". */
goto step_over_function;
/* If we are in a function call trampoline (a stub between
the calling routine and the real function), locate the real
function. That's what tells us (a) whether we want to step
into it at all, and (b) what prologue we want to run to
the end of, if we do step into it. */
tmp = SKIP_TRAMPOLINE_CODE (stop_pc);
if (tmp != 0)
stop_func_start = tmp;
else
{
tmp = DYNAMIC_TRAMPOLINE_NEXTPC (stop_pc);
if (tmp)
{
struct symtab_and_line xxx;
/* Why isn't this s_a_l called "sr_sal", like all of the
other s_a_l's where this code is duplicated? */
INIT_SAL (&xxx); /* initialize to zeroes */
xxx.pc = tmp;
xxx.section = find_pc_overlay (xxx.pc);
step_resume_breakpoint =
set_momentary_breakpoint (xxx, NULL, bp_step_resume);
insert_breakpoints ();
goto keep_going;
}
}
/* If we have line number information for the function we
are thinking of stepping into, step into it.
If there are several symtabs at that PC (e.g. with include
files), just want to know whether *any* of them have line
numbers. find_pc_line handles this. */
{
struct symtab_and_line tmp_sal;
tmp_sal = find_pc_line (stop_func_start, 0);
if (tmp_sal.line != 0)
goto step_into_function;
}
step_over_function:
/* A subroutine call has happened. */
{
/* Set a special breakpoint after the return */
struct symtab_and_line sr_sal;
INIT_SAL (&sr_sal); /* initialize to zeroes */
sr_sal.pc =
ADDR_BITS_REMOVE (SAVED_PC_AFTER_CALL (get_current_frame ()));
sr_sal.section = find_pc_overlay (sr_sal.pc);
step_resume_breakpoint =
set_momentary_breakpoint (sr_sal, get_current_frame (),
bp_step_resume);
if (!IN_SOLIB_DYNSYM_RESOLVE_CODE (sr_sal.pc))
step_resume_breakpoint->frame = step_frame_address;
if (breakpoints_inserted)
insert_breakpoints ();
}
goto keep_going;
step_into_function:
/* Subroutine call with source code we should not step over.
Do step to the first line of code in it. */
{
struct symtab *s;
s = find_pc_symtab (stop_pc);
if (s && s->language != language_asm)
SKIP_PROLOGUE (stop_func_start);
}
sal = find_pc_line (stop_func_start, 0);
/* Use the step_resume_break to step until
the end of the prologue, even if that involves jumps
(as it seems to on the vax under 4.2). */
/* If the prologue ends in the middle of a source line,
continue to the end of that source line (if it is still
within the function). Otherwise, just go to end of prologue. */
#ifdef PROLOGUE_FIRSTLINE_OVERLAP
/* no, don't either. It skips any code that's
legitimately on the first line. */
#else
if (sal.end && sal.pc != stop_func_start && sal.end < stop_func_end)
stop_func_start = sal.end;
#endif
if (stop_func_start == stop_pc)
{
/* We are already there: stop now. */
stop_step = 1;
break;
}
else
/* Put the step-breakpoint there and go until there. */
{
struct symtab_and_line sr_sal;
INIT_SAL (&sr_sal); /* initialize to zeroes */
sr_sal.pc = stop_func_start;
sr_sal.section = find_pc_overlay (stop_func_start);
/* Do not specify what the fp should be when we stop
since on some machines the prologue
is where the new fp value is established. */
step_resume_breakpoint =
set_momentary_breakpoint (sr_sal, NULL, bp_step_resume);
if (breakpoints_inserted)
insert_breakpoints ();
/* And make sure stepping stops right away then. */
step_range_end = step_range_start;
}
goto keep_going;
}
/* We've wandered out of the step range. */
sal = find_pc_line(stop_pc, 0);
if (step_range_end == 1)
{
/* It is stepi or nexti. We always want to stop stepping after
one instruction. */
stop_step = 1;
break;
}
/* If we're in the return path from a shared library trampoline,
we want to proceed through the trampoline when stepping. */
if (IN_SOLIB_RETURN_TRAMPOLINE(stop_pc, stop_func_name))
{
CORE_ADDR tmp;
/* Determine where this trampoline returns. */
tmp = SKIP_TRAMPOLINE_CODE (stop_pc);
/* Only proceed through if we know where it's going. */
if (tmp)
{
/* And put the step-breakpoint there and go until there. */
struct symtab_and_line sr_sal;
INIT_SAL (&sr_sal); /* initialize to zeroes */
sr_sal.pc = tmp;
sr_sal.section = find_pc_overlay (sr_sal.pc);
/* Do not specify what the fp should be when we stop
since on some machines the prologue
is where the new fp value is established. */
step_resume_breakpoint =
set_momentary_breakpoint (sr_sal, NULL, bp_step_resume);
if (breakpoints_inserted)
insert_breakpoints ();
/* Restart without fiddling with the step ranges or
other state. */
goto keep_going;
}
}
if (sal.line == 0)
{
/* We have no line number information. That means to stop
stepping (does this always happen right after one instruction,
when we do "s" in a function with no line numbers,
or can this happen as a result of a return or longjmp?). */
stop_step = 1;
break;
}
if (stop_pc == sal.pc
&& (current_line != sal.line || current_symtab != sal.symtab))
{
/* We are at the start of a different line. So stop. Note that
we don't stop if we step into the middle of a different line.
That is said to make things like for (;;) statements work
better. */
stop_step = 1;
break;
}
/* We aren't done stepping.
Optimize by setting the stepping range to the line.
(We might not be in the original line, but if we entered a
new line in mid-statement, we continue stepping. This makes
things like for(;;) statements work better.) */
if (stop_func_end && sal.end >= stop_func_end)
{
/* If this is the last line of the function, don't keep stepping
(it would probably step us out of the function).
This is particularly necessary for a one-line function,
in which after skipping the prologue we better stop even though
we will be in mid-line. */
stop_step = 1;
break;
}
step_range_start = sal.pc;
step_range_end = sal.end;
step_frame_address = FRAME_FP (get_current_frame ());
current_line = sal.line;
current_symtab = sal.symtab;
goto keep_going;
check_sigtramp2:
if (trap_expected
&& IN_SIGTRAMP (stop_pc, stop_func_name)
&& !IN_SIGTRAMP (prev_pc, prev_func_name)
&& read_sp () INNER_THAN step_sp)
{
/* What has happened here is that we have just stepped the inferior
with a signal (because it is a signal which shouldn't make
us stop), thus stepping into sigtramp.
So we need to set a step_resume_break_address breakpoint
and continue until we hit it, and then step. FIXME: This should
be more enduring than a step_resume breakpoint; we should know
that we will later need to keep going rather than re-hitting
the breakpoint here (see testsuite/gdb.t06/signals.exp where
it says "exceedingly difficult"). */
struct symtab_and_line sr_sal;
INIT_SAL (&sr_sal); /* initialize to zeroes */
sr_sal.pc = prev_pc;
sr_sal.section = find_pc_overlay (sr_sal.pc);
/* We perhaps could set the frame if we kept track of what
the frame corresponding to prev_pc was. But we don't,
so don't. */
through_sigtramp_breakpoint =
set_momentary_breakpoint (sr_sal, NULL, bp_through_sigtramp);
if (breakpoints_inserted)
insert_breakpoints ();
remove_breakpoints_on_following_step = 1;
another_trap = 1;
}
keep_going:
/* Come to this label when you need to resume the inferior.
It's really much cleaner to do a goto than a maze of if-else
conditions. */
/* Save the pc before execution, to compare with pc after stop. */
prev_pc = read_pc (); /* Might have been DECR_AFTER_BREAK */
prev_func_start = stop_func_start; /* Ok, since if DECR_PC_AFTER
BREAK is defined, the
original pc would not have
been at the start of a
function. */
prev_func_name = stop_func_name;
if (update_step_sp)
step_sp = read_sp ();
update_step_sp = 0;
/* If we did not do break;, it means we should keep
running the inferior and not return to debugger. */
if (trap_expected && stop_signal != TARGET_SIGNAL_TRAP)
{
/* We took a signal (which we are supposed to pass through to
the inferior, else we'd have done a break above) and we
haven't yet gotten our trap. Simply continue. */
resume (CURRENTLY_STEPPING (), stop_signal);
}
else
{
/* Either the trap was not expected, but we are continuing
anyway (the user asked that this signal be passed to the
child)
-- or --
The signal was SIGTRAP, e.g. it was our signal, but we
decided we should resume from it.
We're going to run this baby now!
Insert breakpoints now, unless we are trying
to one-proceed past a breakpoint. */
/* If we've just finished a special step resume and we don't
want to hit a breakpoint, pull em out. */
if (step_resume_breakpoint == NULL
&& through_sigtramp_breakpoint == NULL
&& remove_breakpoints_on_following_step)
{
remove_breakpoints_on_following_step = 0;
remove_breakpoints ();
breakpoints_inserted = 0;
}
else if (!breakpoints_inserted &&
(through_sigtramp_breakpoint != NULL || !another_trap))
{
breakpoints_failed = insert_breakpoints ();
if (breakpoints_failed)
break;
breakpoints_inserted = 1;
}
trap_expected = another_trap;
if (stop_signal == TARGET_SIGNAL_TRAP)
stop_signal = TARGET_SIGNAL_0;
#ifdef SHIFT_INST_REGS
/* I'm not sure when this following segment applies. I do know, now,
that we shouldn't rewrite the regs when we were stopped by a
random signal from the inferior process. */
/* FIXME: Shouldn't this be based on the valid bit of the SXIP?
(this is only used on the 88k). */
if (!bpstat_explains_signal (stop_bpstat)
&& (stop_signal != TARGET_SIGNAL_CHLD)
&& !stopped_by_random_signal)
SHIFT_INST_REGS();
#endif /* SHIFT_INST_REGS */
resume (CURRENTLY_STEPPING (), stop_signal);
}
}
stop_stepping:
if (target_has_execution)
{
/* Assuming the inferior still exists, set these up for next
time, just like we did above if we didn't break out of the
loop. */
prev_pc = read_pc ();
prev_func_start = stop_func_start;
prev_func_name = stop_func_name;
}
do_cleanups (old_cleanups);
}
/* Here to return control to GDB when the inferior stops for real.
Print appropriate messages, remove breakpoints, give terminal our modes.
STOP_PRINT_FRAME nonzero means print the executing frame
(pc, function, args, file, line number and line text).
BREAKPOINTS_FAILED nonzero means stop was due to error
attempting to insert breakpoints. */
void
normal_stop ()
{
/* Make sure that the current_frame's pc is correct. This
is a correction for setting up the frame info before doing
DECR_PC_AFTER_BREAK */
if (target_has_execution && get_current_frame())
(get_current_frame ())->pc = read_pc ();
if (breakpoints_failed)
{
target_terminal_ours_for_output ();
print_sys_errmsg ("ptrace", breakpoints_failed);
printf_filtered ("Stopped; cannot insert breakpoints.\n\
The same program may be running in another process.\n");
}
if (target_has_execution && breakpoints_inserted)
if (remove_breakpoints ())
{
target_terminal_ours_for_output ();
printf_filtered ("Cannot remove breakpoints because program is no longer writable.\n\
It might be running in another process.\n\
Further execution is probably impossible.\n");
}
breakpoints_inserted = 0;
/* Delete the breakpoint we stopped at, if it wants to be deleted.
Delete any breakpoint that is to be deleted at the next stop. */
breakpoint_auto_delete (stop_bpstat);
/* If an auto-display called a function and that got a signal,
delete that auto-display to avoid an infinite recursion. */
if (stopped_by_random_signal)
disable_current_display ();
if (step_multi && stop_step)
goto done;
target_terminal_ours ();
if (stop_bpstat
&& stop_bpstat->breakpoint_at
&& stop_bpstat->breakpoint_at->type == bp_shlib_event)
printf_filtered ("Stopped due to shared library event\n");
/* Look up the hook_stop and run it if it exists. */
if (stop_command->hook)
{
catch_errors (hook_stop_stub, (char *)stop_command->hook,
"Error while running hook_stop:\n", RETURN_MASK_ALL);
}
if (!target_has_stack)
goto done;
/* Select innermost stack frame except on return from a stack dummy routine,
or if the program has exited. Print it without a level number if
we have changed functions or hit a breakpoint. Print source line
if we have one. */
if (!stop_stack_dummy)
{
select_frame (get_current_frame (), 0);
if (stop_print_frame)
{
int source_only;
source_only = bpstat_print (stop_bpstat);
source_only = source_only ||
( stop_step
&& step_frame_address == FRAME_FP (get_current_frame ())
&& step_start_function == find_pc_function (stop_pc));
print_stack_frame (selected_frame, -1, source_only? -1: 1);
/* Display the auto-display expressions. */
do_displays ();
}
}
/* Save the function value return registers, if we care.
We might be about to restore their previous contents. */
if (proceed_to_finish)
read_register_bytes (0, stop_registers, REGISTER_BYTES);
if (stop_stack_dummy)
{
/* Pop the empty frame that contains the stack dummy.
POP_FRAME ends with a setting of the current frame, so we
can use that next. */
POP_FRAME;
/* Set stop_pc to what it was before we called the function. Can't rely
on restore_inferior_status because that only gets called if we don't
stop in the called function. */
stop_pc = read_pc();
select_frame (get_current_frame (), 0);
}
done:
annotate_stopped ();
}
static int
hook_stop_stub (cmd)
char *cmd;
{
execute_user_command ((struct cmd_list_element *)cmd, 0);
return (0);
}
int signal_stop_state (signo)
int signo;
{
return signal_stop[signo];
}
int signal_print_state (signo)
int signo;
{
return signal_print[signo];
}
int signal_pass_state (signo)
int signo;
{
return signal_program[signo];
}
static void
sig_print_header ()
{
printf_filtered ("\
Signal Stop\tPrint\tPass to program\tDescription\n");
}
static void
sig_print_info (oursig)
enum target_signal oursig;
{
char *name = target_signal_to_name (oursig);
int name_padding = 13 - strlen (name);
if (name_padding <= 0)
name_padding = 0;
printf_filtered ("%s", name);
printf_filtered ("%*.*s ", name_padding, name_padding, " ");
printf_filtered ("%s\t", signal_stop[oursig] ? "Yes" : "No");
printf_filtered ("%s\t", signal_print[oursig] ? "Yes" : "No");
printf_filtered ("%s\t\t", signal_program[oursig] ? "Yes" : "No");
printf_filtered ("%s\n", target_signal_to_string (oursig));
}
/* Specify how various signals in the inferior should be handled. */
static void
handle_command (args, from_tty)
char *args;
int from_tty;
{
char **argv;
int digits, wordlen;
int sigfirst, signum, siglast;
enum target_signal oursig;
int allsigs;
int nsigs;
unsigned char *sigs;
struct cleanup *old_chain;
if (args == NULL)
{
error_no_arg ("signal to handle");
}
/* Allocate and zero an array of flags for which signals to handle. */
nsigs = (int)TARGET_SIGNAL_LAST;
sigs = (unsigned char *) alloca (nsigs);
memset (sigs, 0, nsigs);
/* Break the command line up into args. */
argv = buildargv (args);
if (argv == NULL)
{
nomem (0);
}
old_chain = make_cleanup ((make_cleanup_func) freeargv, (char *) argv);
/* Walk through the args, looking for signal oursigs, signal names, and
actions. Signal numbers and signal names may be interspersed with
actions, with the actions being performed for all signals cumulatively
specified. Signal ranges can be specified as <LOW>-<HIGH>. */
while (*argv != NULL)
{
wordlen = strlen (*argv);
for (digits = 0; isdigit ((*argv)[digits]); digits++) {;}
allsigs = 0;
sigfirst = siglast = -1;
if (wordlen >= 1 && !strncmp (*argv, "all", wordlen))
{
/* Apply action to all signals except those used by the
debugger. Silently skip those. */
allsigs = 1;
sigfirst = 0;
siglast = nsigs - 1;
}
else if (wordlen >= 1 && !strncmp (*argv, "stop", wordlen))
{
SET_SIGS (nsigs, sigs, signal_stop);
SET_SIGS (nsigs, sigs, signal_print);
}
else if (wordlen >= 1 && !strncmp (*argv, "ignore", wordlen))
{
UNSET_SIGS (nsigs, sigs, signal_program);
}
else if (wordlen >= 2 && !strncmp (*argv, "print", wordlen))
{
SET_SIGS (nsigs, sigs, signal_print);
}
else if (wordlen >= 2 && !strncmp (*argv, "pass", wordlen))
{
SET_SIGS (nsigs, sigs, signal_program);
}
else if (wordlen >= 3 && !strncmp (*argv, "nostop", wordlen))
{
UNSET_SIGS (nsigs, sigs, signal_stop);
}
else if (wordlen >= 3 && !strncmp (*argv, "noignore", wordlen))
{
SET_SIGS (nsigs, sigs, signal_program);
}
else if (wordlen >= 4 && !strncmp (*argv, "noprint", wordlen))
{
UNSET_SIGS (nsigs, sigs, signal_print);
UNSET_SIGS (nsigs, sigs, signal_stop);
}
else if (wordlen >= 4 && !strncmp (*argv, "nopass", wordlen))
{
UNSET_SIGS (nsigs, sigs, signal_program);
}
else if (digits > 0)
{
/* It is numeric. The numeric signal refers to our own internal
signal numbering from target.h, not to host/target signal number.
This is a feature; users really should be using symbolic names
anyway, and the common ones like SIGHUP, SIGINT, SIGALRM, etc.
will work right anyway. */
sigfirst = siglast = (int) target_signal_from_command (atoi (*argv));
if ((*argv)[digits] == '-')
{
siglast =
(int) target_signal_from_command (atoi ((*argv) + digits + 1));
}
if (sigfirst > siglast)
{
/* Bet he didn't figure we'd think of this case... */
signum = sigfirst;
sigfirst = siglast;
siglast = signum;
}
}
else
{
oursig = target_signal_from_name (*argv);
if (oursig != TARGET_SIGNAL_UNKNOWN)
{
sigfirst = siglast = (int)oursig;
}
else
{
/* Not a number and not a recognized flag word => complain. */
error ("Unrecognized or ambiguous flag word: \"%s\".", *argv);
}
}
/* If any signal numbers or symbol names were found, set flags for
which signals to apply actions to. */
for (signum = sigfirst; signum >= 0 && signum <= siglast; signum++)
{
switch ((enum target_signal)signum)
{
case TARGET_SIGNAL_TRAP:
case TARGET_SIGNAL_INT:
if (!allsigs && !sigs[signum])
{
if (query ("%s is used by the debugger.\n\
Are you sure you want to change it? ",
target_signal_to_name
((enum target_signal)signum)))
{
sigs[signum] = 1;
}
else
{
printf_unfiltered ("Not confirmed, unchanged.\n");
gdb_flush (gdb_stdout);
}
}
break;
case TARGET_SIGNAL_0:
case TARGET_SIGNAL_DEFAULT:
case TARGET_SIGNAL_UNKNOWN:
/* Make sure that "all" doesn't print these. */
break;
default:
sigs[signum] = 1;
break;
}
}
argv++;
}
target_notice_signals(inferior_pid);
if (from_tty)
{
/* Show the results. */
sig_print_header ();
for (signum = 0; signum < nsigs; signum++)
{
if (sigs[signum])
{
sig_print_info (signum);
}
}
}
do_cleanups (old_chain);
}
/* Print current contents of the tables set by the handle command.
It is possible we should just be printing signals actually used
by the current target (but for things to work right when switching
targets, all signals should be in the signal tables). */
static void
signals_info (signum_exp, from_tty)
char *signum_exp;
int from_tty;
{
enum target_signal oursig;
sig_print_header ();
if (signum_exp)
{
/* First see if this is a symbol name. */
oursig = target_signal_from_name (signum_exp);
if (oursig == TARGET_SIGNAL_UNKNOWN)
{
/* No, try numeric. */
oursig =
target_signal_from_command (parse_and_eval_address (signum_exp));
}
sig_print_info (oursig);
return;
}
printf_filtered ("\n");
/* These ugly casts brought to you by the native VAX compiler. */
for (oursig = TARGET_SIGNAL_FIRST;
(int)oursig < (int)TARGET_SIGNAL_LAST;
oursig = (enum target_signal)((int)oursig + 1))
{
QUIT;
if (oursig != TARGET_SIGNAL_UNKNOWN
&& oursig != TARGET_SIGNAL_DEFAULT
&& oursig != TARGET_SIGNAL_0)
sig_print_info (oursig);
}
printf_filtered ("\nUse the \"handle\" command to change these tables.\n");
}
/* Save all of the information associated with the inferior<==>gdb
connection. INF_STATUS is a pointer to a "struct inferior_status"
(defined in inferior.h). */
void
save_inferior_status (inf_status, restore_stack_info)
struct inferior_status *inf_status;
int restore_stack_info;
{
inf_status->stop_signal = stop_signal;
inf_status->stop_pc = stop_pc;
inf_status->stop_step = stop_step;
inf_status->stop_stack_dummy = stop_stack_dummy;
inf_status->stopped_by_random_signal = stopped_by_random_signal;
inf_status->trap_expected = trap_expected;
inf_status->step_range_start = step_range_start;
inf_status->step_range_end = step_range_end;
inf_status->step_frame_address = step_frame_address;
inf_status->step_over_calls = step_over_calls;
inf_status->stop_after_trap = stop_after_trap;
inf_status->stop_soon_quietly = stop_soon_quietly;
/* Save original bpstat chain here; replace it with copy of chain.
If caller's caller is walking the chain, they'll be happier if we
hand them back the original chain when restore_i_s is called. */
inf_status->stop_bpstat = stop_bpstat;
stop_bpstat = bpstat_copy (stop_bpstat);
inf_status->breakpoint_proceeded = breakpoint_proceeded;
inf_status->restore_stack_info = restore_stack_info;
inf_status->proceed_to_finish = proceed_to_finish;
memcpy (inf_status->stop_registers, stop_registers, REGISTER_BYTES);
read_register_bytes (0, inf_status->registers, REGISTER_BYTES);
record_selected_frame (&(inf_status->selected_frame_address),
&(inf_status->selected_level));
return;
}
struct restore_selected_frame_args {
CORE_ADDR frame_address;
int level;
};
static int restore_selected_frame PARAMS ((char *));
/* Restore the selected frame. args is really a struct
restore_selected_frame_args * (declared as char * for catch_errors)
telling us what frame to restore. Returns 1 for success, or 0 for
failure. An error message will have been printed on error. */
static int
restore_selected_frame (args)
char *args;
{
struct restore_selected_frame_args *fr =
(struct restore_selected_frame_args *) args;
struct frame_info *frame;
int level = fr->level;
frame = find_relative_frame (get_current_frame (), &level);
/* If inf_status->selected_frame_address is NULL, there was no
previously selected frame. */
if (frame == NULL ||
FRAME_FP (frame) != fr->frame_address ||
level != 0)
{
warning ("Unable to restore previously selected frame.\n");
return 0;
}
select_frame (frame, fr->level);
return(1);
}
void
restore_inferior_status (inf_status)
struct inferior_status *inf_status;
{
stop_signal = inf_status->stop_signal;
stop_pc = inf_status->stop_pc;
stop_step = inf_status->stop_step;
stop_stack_dummy = inf_status->stop_stack_dummy;
stopped_by_random_signal = inf_status->stopped_by_random_signal;
trap_expected = inf_status->trap_expected;
step_range_start = inf_status->step_range_start;
step_range_end = inf_status->step_range_end;
step_frame_address = inf_status->step_frame_address;
step_over_calls = inf_status->step_over_calls;
stop_after_trap = inf_status->stop_after_trap;
stop_soon_quietly = inf_status->stop_soon_quietly;
bpstat_clear (&stop_bpstat);
stop_bpstat = inf_status->stop_bpstat;
breakpoint_proceeded = inf_status->breakpoint_proceeded;
proceed_to_finish = inf_status->proceed_to_finish;
memcpy (stop_registers, inf_status->stop_registers, REGISTER_BYTES);
/* The inferior can be gone if the user types "print exit(0)"
(and perhaps other times). */
if (target_has_execution)
write_register_bytes (0, inf_status->registers, REGISTER_BYTES);
/* The inferior can be gone if the user types "print exit(0)"
(and perhaps other times). */
/* FIXME: If we are being called after stopping in a function which
is called from gdb, we should not be trying to restore the
selected frame; it just prints a spurious error message (The
message is useful, however, in detecting bugs in gdb (like if gdb
clobbers the stack)). In fact, should we be restoring the
inferior status at all in that case? . */
if (target_has_stack && inf_status->restore_stack_info)
{
struct restore_selected_frame_args fr;
fr.level = inf_status->selected_level;
fr.frame_address = inf_status->selected_frame_address;
/* The point of catch_errors is that if the stack is clobbered,
walking the stack might encounter a garbage pointer and error()
trying to dereference it. */
if (catch_errors (restore_selected_frame, &fr,
"Unable to restore previously selected frame:\n",
RETURN_MASK_ERROR) == 0)
/* Error in restoring the selected frame. Select the innermost
frame. */
select_frame (get_current_frame (), 0);
}
}
void
_initialize_infrun ()
{
register int i;
register int numsigs;
add_info ("signals", signals_info,
"What debugger does when program gets various signals.\n\
Specify a signal as argument to print info on that signal only.");
add_info_alias ("handle", "signals", 0);
add_com ("handle", class_run, handle_command,
concat ("Specify how to handle a signal.\n\
Args are signals and actions to apply to those signals.\n\
Symbolic signals (e.g. SIGSEGV) are recommended but numeric signals\n\
from 1-15 are allowed for compatibility with old versions of GDB.\n\
Numeric ranges may be specified with the form LOW-HIGH (e.g. 1-5).\n\
The special arg \"all\" is recognized to mean all signals except those\n\
used by the debugger, typically SIGTRAP and SIGINT.\n",
"Recognized actions include \"stop\", \"nostop\", \"print\", \"noprint\",\n\
\"pass\", \"nopass\", \"ignore\", or \"noignore\".\n\
Stop means reenter debugger if this signal happens (implies print).\n\
Print means print a message if this signal happens.\n\
Pass means let program see this signal; otherwise program doesn't know.\n\
Ignore is a synonym for nopass and noignore is a synonym for pass.\n\
Pass and Stop may be combined.", NULL));
stop_command = add_cmd ("stop", class_obscure, not_just_help_class_command,
"There is no `stop' command, but you can set a hook on `stop'.\n\
This allows you to set a list of commands to be run each time execution\n\
of the program stops.", &cmdlist);
numsigs = (int)TARGET_SIGNAL_LAST;
signal_stop = (unsigned char *)
xmalloc (sizeof (signal_stop[0]) * numsigs);
signal_print = (unsigned char *)
xmalloc (sizeof (signal_print[0]) * numsigs);
signal_program = (unsigned char *)
xmalloc (sizeof (signal_program[0]) * numsigs);
for (i = 0; i < numsigs; i++)
{
signal_stop[i] = 1;
signal_print[i] = 1;
signal_program[i] = 1;
}
/* Signals caused by debugger's own actions
should not be given to the program afterwards. */
signal_program[TARGET_SIGNAL_TRAP] = 0;
signal_program[TARGET_SIGNAL_INT] = 0;
/* Signals that are not errors should not normally enter the debugger. */
signal_stop[TARGET_SIGNAL_ALRM] = 0;
signal_print[TARGET_SIGNAL_ALRM] = 0;
signal_stop[TARGET_SIGNAL_VTALRM] = 0;
signal_print[TARGET_SIGNAL_VTALRM] = 0;
signal_stop[TARGET_SIGNAL_PROF] = 0;
signal_print[TARGET_SIGNAL_PROF] = 0;
signal_stop[TARGET_SIGNAL_CHLD] = 0;
signal_print[TARGET_SIGNAL_CHLD] = 0;
signal_stop[TARGET_SIGNAL_IO] = 0;
signal_print[TARGET_SIGNAL_IO] = 0;
signal_stop[TARGET_SIGNAL_POLL] = 0;
signal_print[TARGET_SIGNAL_POLL] = 0;
signal_stop[TARGET_SIGNAL_URG] = 0;
signal_print[TARGET_SIGNAL_URG] = 0;
#ifdef SOLIB_ADD
add_show_from_set
(add_set_cmd ("stop-on-solib-events", class_support, var_zinteger,
(char *) &stop_on_solib_events,
"Set stopping for shared library events.\n\
If nonzero, gdb will give control to the user when the dynamic linker\n\
notifies gdb of shared library events. The most common event of interest\n\
to the user would be loading/unloading of a new library.\n",
&setlist),
&showlist);
#endif
}
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