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Re: [RFA] Stop infrun from tracking breakpoint insertion status.
- From: Vladimir Prus <vladimir at codesourcery dot com>
- To: "Ulrich Weigand" <uweigand at de dot ibm dot com>
- Cc: gdb-patches at sources dot redhat dot com
- Date: Tue, 20 Nov 2007 23:48:44 +0300
- Subject: Re: [RFA] Stop infrun from tracking breakpoint insertion status.
- References: <200711191139.lAJBdRFc027229@d12av02.megacenter.de.ibm.com>
On Monday 19 November 2007 14:39:27 you wrote:
> Vladimir Prus wrote:
>
> > diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
> > index e81ec20..ef55a3d 100644
> > --- a/gdb/breakpoint.c
> > +++ b/gdb/breakpoint.c
> > @@ -296,6 +296,8 @@ int breakpoint_count;
> > /* Pointer to current exception event record */
> > static struct exception_event_record *current_exception_event;
> >
> > +static int breakpoints_meant_to_be_inserted_p;
> > +
> > /* This function returns a pointer to the string representation of the
> > pathname of the dynamically-linked library that has just been
> > loaded.
> > @@ -1312,6 +1314,12 @@ remove_breakpoints (void)
> > }
> >
> > int
> > +breakpoints_meant_to_be_inserted (void)
> > +{
> > + return breakpoints_meant_to_be_inserted_p;
> > +}
> > +
> > +int
> > remove_hw_watchpoints (void)
> > {
> > struct bp_location *b;
>
>
> Is the breakpoints_meant_to_be_inserted_p variable actually ever
> set to any non-zero value in this patch?
I have looked into why I got no failures with the previous version
of the patch.
The use of breakpoints_meant_to_be_inserted in handle_inferiour_event,
for the TARGET_WAITKIND_LOADED, did not matter because
TARGET_WAITKIND_LOADED is used by just a few targets.
And even if remote.c can use it, it does not do when
using gdbserver, which makes it hard to test.
The reason that use in keep_going does not break anything is that
the intention of the code is to insert breakpoints, unless either
they are already inserted, or ecs->another_trap is non-zero. However,
insert_bp_location will immediately return if breakpoint location
is already inserted. Therefore, the "already inserted" check is
not necessary at all, and I removed it.
As for the use in insert_step_resume_breakpoint_at_sal, I must admit
I've got lost in the code again -- I don't know how previous version
of the patch did not cause any problems.
This version of patch makes breakpoints_meant_to_be_inserted
actually return 0 and 1 as needed, and adjust keep_going. OK?
- Volodya
The checks of breakpoints_inserted before calling remove_breakpoints
are removed, as remove_breakpoint won't touch uninserted breakpoints.
In a number of places, we're interested if a breakpoint is inserted
at particular PC, and we now use breakpoint_inserted_here_p. In a few
places, breakpoints_inserted indicates if infrun.c expects breakpoints
to be inserted in the target, and that state is now kept in breakpoint.c
* breakpoint.h (breakpoints_meant_to_be_inserted): New
declaration.
* breakpoint.c (breakpoints_meant_to_be_inserted_p): New.
(breakpoints_meant_to_be_inserted): New.
* infrun.c (breakpoints_inserted): Remove.
(resume): Don't check for breakpoints_inserted before
remove_hw_watchpoints. Use breakpoint_inserted_here_p.
(proceed, init_wait_for_inferior): Don't set breakpoints_inserted.
(handle_inferior_event): Don't use breakpoints_inserted.
Use breakpoints_meant_to_be_inserted and
breakpoints_inserted_here_p.
(insert_step_resume_breakpoint_at_sal, keep_going): Use
breakpoints_meant_to_be_inserted. Don't set breakpoints_inserted.
(normal_stop): Don't check for breakpoints_inserted. Don't
set breakpoints_inserted.
(keep_going): Don't check for breakpoints_inserted.
---
gdb/breakpoint.c | 12 +++++++++++
gdb/breakpoint.h | 7 ++++++
gdb/infrun.c | 59 +++++++++++++++++------------------------------------
3 files changed, 38 insertions(+), 40 deletions(-)
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 81614aa..d2bd232 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -296,6 +296,8 @@ int breakpoint_count;
/* Pointer to current exception event record */
static struct exception_event_record *current_exception_event;
+static int breakpoints_meant_to_be_inserted_p;
+
/* This function returns a pointer to the string representation of the
pathname of the dynamically-linked library that has just been
loaded.
@@ -1235,6 +1237,8 @@ insert_breakpoints (void)
struct ui_file *tmp_error_stream = mem_fileopen ();
make_cleanup_ui_file_delete (tmp_error_stream);
+ breakpoints_meant_to_be_inserted_p = 1;
+
/* Explicitly mark the warning -- this will only be printed if
there was an error. */
fprintf_unfiltered (tmp_error_stream, "Warning:\n");
@@ -1299,6 +1303,8 @@ remove_breakpoints (void)
struct bp_location *b;
int val;
+ breakpoints_meant_to_be_inserted_p = 0;
+
ALL_BP_LOCATIONS (b)
{
if (b->inserted)
@@ -1312,6 +1318,12 @@ remove_breakpoints (void)
}
int
+breakpoints_meant_to_be_inserted (void)
+{
+ return breakpoints_meant_to_be_inserted_p;
+}
+
+int
remove_hw_watchpoints (void)
{
struct bp_location *b;
diff --git a/gdb/breakpoint.h b/gdb/breakpoint.h
index e4aa72a..236cd7b 100644
--- a/gdb/breakpoint.h
+++ b/gdb/breakpoint.h
@@ -854,4 +854,11 @@ extern int deprecated_remove_raw_breakpoint (void *);
target. */
int watchpoints_triggered (struct target_waitstatus *);
+/* Returns non-zero if insert_breakpoints was previously called,
+ and remove_breakpoints was not called after that.
+ This function allows to figure out if we meant that all breakpoints
+ be inserted in inferior. If so, any new breakpoints possibly
+ created must be inserted as well. */
+extern int breakpoints_meant_to_be_inserted (void);
+
#endif /* !defined (BREAKPOINT_H) */
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 85d889a..9a1c24f 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -214,10 +214,6 @@ static unsigned char *signal_program;
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;
@@ -519,7 +515,7 @@ resume (int step, enum target_signal sig)
Work around the problem by removing hardware watchpoints if a step is
requested, GDB will check for a hardware watchpoint trigger after the
step anyway. */
- if (CANNOT_STEP_HW_WATCHPOINTS && step && breakpoints_inserted)
+ if (CANNOT_STEP_HW_WATCHPOINTS && step)
remove_hw_watchpoints ();
@@ -634,7 +630,7 @@ a command like `return' or `jump' to continue execution."));
/* 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 ()))
+ if (step && breakpoint_inserted_here_p (read_pc ()))
step = 0;
}
target_resume (resume_ptid, step, sig);
@@ -783,12 +779,7 @@ proceed (CORE_ADDR addr, enum target_signal siggnal, int step)
Continue it automatically and insert breakpoints then. */
trap_expected = 1;
else
- {
- insert_breakpoints ();
- /* If we get here there was no call to error() in
- insert breakpoints -- so they were inserted. */
- breakpoints_inserted = 1;
- }
+ insert_breakpoints ();
if (siggnal != TARGET_SIGNAL_DEFAULT)
stop_signal = siggnal;
@@ -884,7 +875,6 @@ init_wait_for_inferior (void)
/* These are meaningless until the first time through wait_for_inferior. */
prev_pc = 0;
- breakpoints_inserted = 0;
breakpoint_init_inferior (inf_starting);
/* Don't confuse first call to proceed(). */
@@ -1334,10 +1324,8 @@ handle_inferior_event (struct execution_control_state *ecs)
/* Remove breakpoints, SOLIB_ADD might adjust
breakpoint addresses via breakpoint_re_set. */
- breakpoints_were_inserted = breakpoints_inserted;
- if (breakpoints_inserted)
- remove_breakpoints ();
- breakpoints_inserted = 0;
+ breakpoints_were_inserted = breakpoints_meant_to_be_inserted ();
+ remove_breakpoints ();
/* Check for any newly added shared libraries if we're
supposed to be adding them automatically. Switch
@@ -1381,10 +1369,7 @@ handle_inferior_event (struct execution_control_state *ecs)
/* Reinsert breakpoints and continue. */
if (breakpoints_were_inserted)
- {
- insert_breakpoints ();
- breakpoints_inserted = 1;
- }
+ insert_breakpoints ();
}
/* If we are skipping through a shell, or through shared library
@@ -1670,7 +1655,7 @@ handle_inferior_event (struct execution_control_state *ecs)
/* Check if a regular breakpoint has been hit before checking
for a potential single step breakpoint. Otherwise, GDB will
not see this breakpoint hit when stepping onto breakpoints. */
- if (breakpoints_inserted && breakpoint_here_p (stop_pc))
+ if (breakpoint_inserted_here_p (stop_pc))
{
ecs->random_signal = 0;
if (!breakpoint_thread_match (stop_pc, ecs->ptid))
@@ -1783,7 +1768,6 @@ handle_inferior_event (struct execution_control_state *ecs)
}
else
{ /* Single step */
- breakpoints_inserted = 0;
if (!ptid_equal (inferior_ptid, ecs->ptid))
context_switch (ecs);
ecs->waiton_ptid = ecs->ptid;
@@ -1945,7 +1929,7 @@ handle_inferior_event (struct execution_control_state *ecs)
stack. */
if (stop_signal == TARGET_SIGNAL_TRAP
- || (breakpoints_inserted
+ || (breakpoint_inserted_here_p (stop_pc)
&& (stop_signal == TARGET_SIGNAL_ILL
|| stop_signal == TARGET_SIGNAL_SEGV
|| stop_signal == TARGET_SIGNAL_EMT))
@@ -2076,8 +2060,8 @@ process_event_stop_test:
stop_signal = TARGET_SIGNAL_0;
if (prev_pc == read_pc ()
- && !breakpoints_inserted
&& breakpoint_here_p (read_pc ())
+ && !breakpoint_inserted_here_p (read_pc ())
&& step_resume_breakpoint == NULL)
{
/* We were just starting a new sequence, attempting to
@@ -2150,7 +2134,6 @@ process_event_stop_test:
fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_SET_LONGJMP_RESUME\n");
disable_longjmp_breakpoint ();
remove_breakpoints ();
- breakpoints_inserted = 0;
if (!gdbarch_get_longjmp_target_p (current_gdbarch)
|| !gdbarch_get_longjmp_target (current_gdbarch,
get_current_frame (), &jmp_buf_pc))
@@ -2176,7 +2159,6 @@ process_event_stop_test:
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_CLEAR_LONGJMP_RESUME\n");
remove_breakpoints ();
- breakpoints_inserted = 0;
disable_longjmp_breakpoint ();
ecs->handling_longjmp = 0; /* FIXME */
if (what.main_action == BPSTAT_WHAT_CLEAR_LONGJMP_RESUME)
@@ -2186,9 +2168,7 @@ process_event_stop_test:
case BPSTAT_WHAT_SINGLE:
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_SINGLE\n");
- if (breakpoints_inserted)
- remove_breakpoints ();
- breakpoints_inserted = 0;
+ remove_breakpoints ();
ecs->another_trap = 1;
/* Still need to check other stuff, at least the case
where we are stepping and step out of the right range. */
@@ -2250,7 +2230,6 @@ process_event_stop_test:
to doing that. */
ecs->step_after_step_resume_breakpoint = 0;
remove_breakpoints ();
- breakpoints_inserted = 0;
ecs->another_trap = 1;
keep_going (ecs);
return;
@@ -2265,9 +2244,7 @@ process_event_stop_test:
/* 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;
+ remove_breakpoints ();
/* Check for any newly added shared libraries if we're
supposed to be adding them automatically. Switch
@@ -2870,7 +2847,7 @@ insert_step_resume_breakpoint_at_sal (struct symtab_and_line sr_sal,
step_resume_breakpoint = set_momentary_breakpoint (sr_sal, sr_id,
bp_step_resume);
- if (breakpoints_inserted)
+ if (breakpoints_meant_to_be_inserted ())
insert_breakpoints ();
}
@@ -2968,9 +2945,13 @@ keep_going (struct execution_control_state *ecs)
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! */
+ We're going to run this baby now!
- if (!breakpoints_inserted && !ecs->another_trap)
+ Note that insert_breakpoints won't try to re-insert
+ already inserted breakpoints. Therefore, we don't
+ care if breakpoints were already inserted, or not. */
+
+ if (!ecs->another_trap)
{
/* Stop stepping when inserting breakpoints
has failed. */
@@ -2979,7 +2960,6 @@ keep_going (struct execution_control_state *ecs)
stop_stepping (ecs);
return;
}
- breakpoints_inserted = 1;
}
trap_expected = ecs->another_trap;
@@ -3172,7 +3152,7 @@ normal_stop (void)
gdbarch_decr_pc_after_break needs to just go away. */
deprecated_update_frame_pc_hack (get_current_frame (), read_pc ());
- if (target_has_execution && breakpoints_inserted)
+ if (target_has_execution)
{
if (remove_breakpoints ())
{
@@ -3183,7 +3163,6 @@ 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. */