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Add enum for result of fast_tracepoint_collecting

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I got confused by the result value of fast_tracepoint_collecting, while
it sounds like it would return true/false (whether the thread is
collecting or not), it actually returns:

  0: not collecting
  1: in the jump pad, before the relocated instruction
  2: in the jump pad, at or after the relocated instruction

To avoid confusion, I think it would be nice to make it return an enum.
If you can help find a shorter but still relavant name, it would be
awesome.  Otherwise, we'll go with that, fast_tpoint_collect_result,
which is at least consistent with the existing
fast_tpoint_collect_status.

gdb/gdbserver/ChangeLog:

	* tracepoint.h (enum class fast_tpoint_collect_result): New
	enumeration.
	(fast_tracepoint_collecting): Change return type to
	fast_tpoint_collect_result.
	* tracepoint.c (fast_tracepoint_collecting): Likewise.
	* linux-low.h: Include tracepoint.h.
	(struct lwp_info) <collecting_fast_tracepoint>: Change type to
	fast_tpoint_collect_result.
	* linux-low.c (handle_tracepoints): Adjust.
	(linux_fast_tracepoint_collecting): Change return type to
	fast_tpoint_collect_result.
	(maybe_move_out_of_jump_pad, linux_wait_for_event_filtered,
	linux_wait_1, stuck_in_jump_pad_callback,
	lwp_signal_can_be_delivered, linux_resume_one_lwp_throw,
	proceed_one_lwp): Adjust to type change.
This commit is contained in:
Simon Marchi 2017-07-26 10:55:35 +02:00
parent 11f1093690
commit 229d26fc9e
5 changed files with 91 additions and 44 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
gdb/gdbserver/ChangeLog
View file

@ -1,3 +1,21 @@
2017-07-26 Simon Marchi <simon.marchi@ericsson.com>
* tracepoint.h (enum class fast_tpoint_collect_result): New
enumeration.
(fast_tracepoint_collecting): Change return type to
fast_tpoint_collect_result.
* tracepoint.c (fast_tracepoint_collecting): Likewise.
* linux-low.h: Include tracepoint.h.
(struct lwp_info) <collecting_fast_tracepoint>: Change type to
fast_tpoint_collect_result.
* linux-low.c (handle_tracepoints): Adjust.
(linux_fast_tracepoint_collecting): Change return type to
fast_tpoint_collect_result.
(maybe_move_out_of_jump_pad, linux_wait_for_event_filtered,
linux_wait_1, stuck_in_jump_pad_callback,
lwp_signal_can_be_delivered, linux_resume_one_lwp_throw,
proceed_one_lwp): Adjust to type change.
2017-07-10 Yao Qi <yao.qi@linaro.org>
* linux-x86-low.c (x86_linux_read_description): Re-indent the code.

65
gdb/gdbserver/linux-low.c
View file

@ -2082,7 +2082,9 @@ handle_tracepoints (struct lwp_info *lwp)
lwp_suspended_decr (lwp);
gdb_assert (lwp->suspended == 0);
gdb_assert (!stabilizing_threads || lwp->collecting_fast_tracepoint);
gdb_assert (!stabilizing_threads
|| (lwp->collecting_fast_tracepoint
!= fast_tpoint_collect_result::not_collecting));
if (tpoint_related_event)
{
@ -2094,10 +2096,10 @@ handle_tracepoints (struct lwp_info *lwp)
return 0;
}
/* Convenience wrapper. Returns true if LWP is presently collecting a
fast tracepoint. */
/* Convenience wrapper. Returns information about LWP's fast tracepoint
collection status. */
static int
static fast_tpoint_collect_result
linux_fast_tracepoint_collecting (struct lwp_info *lwp,
struct fast_tpoint_collect_status *status)
{
@ -2105,14 +2107,14 @@ linux_fast_tracepoint_collecting (struct lwp_info *lwp,
struct thread_info *thread = get_lwp_thread (lwp);
if (the_low_target.get_thread_area == NULL)
return 0;
return fast_tpoint_collect_result::not_collecting;
/* Get the thread area address. This is used to recognize which
thread is which when tracing with the in-process agent library.
We don't read anything from the address, and treat it as opaque;
it's the address itself that we assume is unique per-thread. */
if ((*the_low_target.get_thread_area) (lwpid_of (thread), &thread_area) == -1)
return 0;
return fast_tpoint_collect_result::not_collecting;
return fast_tracepoint_collecting (thread_area, lwp->stop_pc, status);
}
@ -2136,14 +2138,14 @@ maybe_move_out_of_jump_pad (struct lwp_info *lwp, int *wstat)
&& agent_loaded_p ())
{
struct fast_tpoint_collect_status status;
int r;
if (debug_threads)
debug_printf ("Checking whether LWP %ld needs to move out of the "
"jump pad.\n",
lwpid_of (current_thread));
r = linux_fast_tracepoint_collecting (lwp, &status);
fast_tpoint_collect_result r
= linux_fast_tracepoint_collecting (lwp, &status);
if (wstat == NULL
|| (WSTOPSIG (*wstat) != SIGILL
@ -2153,9 +2155,10 @@ maybe_move_out_of_jump_pad (struct lwp_info *lwp, int *wstat)
{
lwp->collecting_fast_tracepoint = r;
if (r != 0)
if (r != fast_tpoint_collect_result::not_collecting)
{
if (r == 1 && lwp->exit_jump_pad_bkpt == NULL)
if (r == fast_tpoint_collect_result::before_insn
&& lwp->exit_jump_pad_bkpt == NULL)
{
/* Haven't executed the original instruction yet.
Set breakpoint there, and wait till it's hit,
@ -2181,9 +2184,10 @@ maybe_move_out_of_jump_pad (struct lwp_info *lwp, int *wstat)
reporting to GDB. Otherwise, it's an IPA lib bug: just
report the signal to GDB, and pray for the best. */
lwp->collecting_fast_tracepoint = 0;
lwp->collecting_fast_tracepoint
= fast_tpoint_collect_result::not_collecting;
if (r != 0
if (r != fast_tpoint_collect_result::not_collecting
&& (status.adjusted_insn_addr <= lwp->stop_pc
&& lwp->stop_pc < status.adjusted_insn_addr_end))
{
@ -2715,7 +2719,8 @@ linux_wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid,
if (stopping_threads == NOT_STOPPING_THREADS
&& requested_child->status_pending_p
&& requested_child->collecting_fast_tracepoint)
&& (requested_child->collecting_fast_tracepoint
!= fast_tpoint_collect_result::not_collecting))
{
enqueue_one_deferred_signal (requested_child,
&requested_child->status_pending);
@ -3467,20 +3472,22 @@ linux_wait_1 (ptid_t ptid,
}
}
if (event_child->collecting_fast_tracepoint)
if (event_child->collecting_fast_tracepoint
!= fast_tpoint_collect_result::not_collecting)
{
if (debug_threads)
debug_printf ("LWP %ld was trying to move out of the jump pad (%d). "
"Check if we're already there.\n",
lwpid_of (current_thread),
event_child->collecting_fast_tracepoint);
(int) event_child->collecting_fast_tracepoint);
trace_event = 1;
event_child->collecting_fast_tracepoint
= linux_fast_tracepoint_collecting (event_child, NULL);
if (event_child->collecting_fast_tracepoint != 1)
if (event_child->collecting_fast_tracepoint
!= fast_tpoint_collect_result::before_insn)
{
/* No longer need this breakpoint. */
if (event_child->exit_jump_pad_bkpt != NULL)
@ -3507,7 +3514,8 @@ linux_wait_1 (ptid_t ptid,
}
}
if (event_child->collecting_fast_tracepoint == 0)
if (event_child->collecting_fast_tracepoint
== fast_tpoint_collect_result::not_collecting)
{
if (debug_threads)
debug_printf ("fast tracepoint finished "
@ -4192,7 +4200,8 @@ stuck_in_jump_pad_callback (struct inferior_list_entry *entry, void *data)
&& (gdb_breakpoint_here (lwp->stop_pc)
|| lwp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT
|| thread->last_resume_kind == resume_step)
&& linux_fast_tracepoint_collecting (lwp, NULL));
&& (linux_fast_tracepoint_collecting (lwp, NULL)
!= fast_tpoint_collect_result::not_collecting));
}
static void
@ -4369,7 +4378,8 @@ single_step (struct lwp_info* lwp)
static int
lwp_signal_can_be_delivered (struct lwp_info *lwp)
{
return !lwp->collecting_fast_tracepoint;
return (lwp->collecting_fast_tracepoint
== fast_tpoint_collect_result::not_collecting);
}
/* Resume execution of LWP. If STEP is nonzero, single-step it. If
@ -4381,7 +4391,6 @@ linux_resume_one_lwp_throw (struct lwp_info *lwp,
{
struct thread_info *thread = get_lwp_thread (lwp);
struct thread_info *saved_thread;
int fast_tp_collecting;
int ptrace_request;
struct process_info *proc = get_thread_process (thread);
@ -4397,9 +4406,12 @@ linux_resume_one_lwp_throw (struct lwp_info *lwp,
gdb_assert (lwp->waitstatus.kind == TARGET_WAITKIND_IGNORE);
fast_tp_collecting = lwp->collecting_fast_tracepoint;
fast_tpoint_collect_result fast_tp_collecting
= lwp->collecting_fast_tracepoint;
gdb_assert (!stabilizing_threads || fast_tp_collecting);
gdb_assert (!stabilizing_threads
|| (fast_tp_collecting
!= fast_tpoint_collect_result::not_collecting));
/* Cancel actions that rely on GDB not changing the PC (e.g., the
user used the "jump" command, or "set $pc = foo"). */
@ -4455,7 +4467,7 @@ linux_resume_one_lwp_throw (struct lwp_info *lwp,
if (can_hardware_single_step ())
{
if (fast_tp_collecting == 0)
if (fast_tp_collecting == fast_tpoint_collect_result::not_collecting)
{
if (step == 0)
warning ("BAD - reinserting but not stepping.");
@ -4468,14 +4480,14 @@ linux_resume_one_lwp_throw (struct lwp_info *lwp,
step = maybe_hw_step (thread);
}
if (fast_tp_collecting == 1)
if (fast_tp_collecting == fast_tpoint_collect_result::before_insn)
{
if (debug_threads)
debug_printf ("lwp %ld wants to get out of fast tracepoint jump pad"
" (exit-jump-pad-bkpt)\n",
lwpid_of (thread));
}
else if (fast_tp_collecting == 2)
else if (fast_tp_collecting == fast_tpoint_collect_result::at_insn)
{
if (debug_threads)
debug_printf ("lwp %ld wants to get out of fast tracepoint jump pad"
@ -5294,7 +5306,8 @@ proceed_one_lwp (struct inferior_list_entry *entry, void *except)
if (thread->last_resume_kind == resume_stop
&& lwp->pending_signals_to_report == NULL
&& lwp->collecting_fast_tracepoint == 0)
&& (lwp->collecting_fast_tracepoint
== fast_tpoint_collect_result::not_collecting))
{
/* We haven't reported this LWP as stopped yet (otherwise, the
last_status.kind check above would catch it, and we wouldn't

12
gdb/gdbserver/linux-low.h
View file

@ -26,6 +26,7 @@
/* Included for ptrace type definitions. */
#include "nat/linux-ptrace.h"
#include "target/waitstatus.h" /* For enum target_stop_reason. */
#include "tracepoint.h"
#define PTRACE_XFER_TYPE long
@ -353,12 +354,11 @@ struct lwp_info
and then processed and cleared in linux_resume_one_lwp. */
struct thread_resume *resume;
/* True if it is known that this lwp is presently collecting a fast
tracepoint (it is in the jump pad or in some code that will
return to the jump pad. Normally, we won't care about this, but
we will if a signal arrives to this lwp while it is
collecting. */
int collecting_fast_tracepoint;
/* Information bout this lwp's fast tracepoint collection status (is it
currently stopped in the jump pad, and if so, before or at/after the
relocated instruction). Normally, we won't care about this, but we will
if a signal arrives to this lwp while it is collecting. */
fast_tpoint_collect_result collecting_fast_tracepoint;
/* If this is non-zero, it points to a chain of signals which need
to be reported to GDB. These were deferred because the thread

18
gdb/gdbserver/tracepoint.c
View file

@ -5581,7 +5581,7 @@ force_unlock_trace_buffer (void)
case, if we want to move the thread out of the jump pad, we need to
single-step it until this function returns 0. */
int
fast_tpoint_collect_result
fast_tracepoint_collecting (CORE_ADDR thread_area,
CORE_ADDR stop_pc,
struct fast_tpoint_collect_status *status)
@ -5656,7 +5656,7 @@ fast_tracepoint_collecting (CORE_ADDR thread_area,
if (tpoint == NULL)
{
warning ("in jump pad, but no matching tpoint?");
return 0;
return fast_tpoint_collect_result::not_collecting;
}
else
{
@ -5684,7 +5684,7 @@ fast_tracepoint_collecting (CORE_ADDR thread_area,
if (tpoint == NULL)
{
warning ("in trampoline, but no matching tpoint?");
return 0;
return fast_tpoint_collect_result::not_collecting;
}
else
{
@ -5712,14 +5712,14 @@ fast_tracepoint_collecting (CORE_ADDR thread_area,
{
trace_debug ("fast_tracepoint_collecting:"
" failed reading 'collecting' in the inferior");
return 0;
return fast_tpoint_collect_result::not_collecting;
}
if (!ipa_collecting)
{
trace_debug ("fast_tracepoint_collecting: not collecting"
" (and nobody is).");
return 0;
return fast_tpoint_collect_result::not_collecting;
}
/* Some thread is collecting. Check which. */
@ -5732,7 +5732,7 @@ fast_tracepoint_collecting (CORE_ADDR thread_area,
{
trace_debug ("fast_tracepoint_collecting: not collecting "
"(another thread is)");
return 0;
return fast_tpoint_collect_result::not_collecting;
}
tpoint
@ -5742,7 +5742,7 @@ fast_tracepoint_collecting (CORE_ADDR thread_area,
warning ("fast_tracepoint_collecting: collecting, "
"but tpoint %s not found?",
paddress ((CORE_ADDR) ipa_collecting_obj.tpoint));
return 0;
return fast_tpoint_collect_result::not_collecting;
}
/* The thread is within `gdb_collect', skip over the rest of
@ -5769,7 +5769,7 @@ fast_tracepoint_collecting (CORE_ADDR thread_area,
fast_tracepoint_collecting, returning continue-until-break at %s",
paddress (tpoint->adjusted_insn_addr));
return 1; /* continue */
return fast_tpoint_collect_result::before_insn; /* continue */
}
else
{
@ -5780,7 +5780,7 @@ fast_tracepoint_collecting, returning continue-until-break at %s",
paddress (tpoint->adjusted_insn_addr),
paddress (tpoint->adjusted_insn_addr_end));
return 2; /* single-step */
return fast_tpoint_collect_result::at_insn; /* single-step */
}
}

22
gdb/gdbserver/tracepoint.h
View file

@ -115,9 +115,25 @@ struct fast_tpoint_collect_status
CORE_ADDR adjusted_insn_addr_end;
};
int fast_tracepoint_collecting (CORE_ADDR thread_area,
CORE_ADDR stop_pc,
struct fast_tpoint_collect_status *status);
/* The possible states a thread can be in, related to the collection of fast
tracepoint. */
enum class fast_tpoint_collect_result
{
/* Not collecting a fast tracepoint. */
not_collecting,
/* In the jump pad, but before the relocated instruction. */
before_insn,
/* In the jump pad, but at (or after) the relocated instruction. */
at_insn,
};
fast_tpoint_collect_result fast_tracepoint_collecting
(CORE_ADDR thread_area, CORE_ADDR stop_pc,
struct fast_tpoint_collect_status *status);
void force_unlock_trace_buffer (void);
int handle_tracepoint_bkpts (struct thread_info *tinfo, CORE_ADDR stop_pc);