Place displaced step data directly in inferior structure
Commit Message
This patch moves the per-inferior data related to displaced stepping to
be directly in the inferior structure, rather than in a container on the
side.
On notable difference is that previously, we deleted the state on
inferior exit, which guaranteed a clean state if re-using the inferior
for a new run or attach. We now need to reset the state manually.
gdb/ChangeLog:
* inferior.h (class inferior) <displaced_step_state>: New field.
* infrun.h (struct displaced_step_state): Move here from
infrun.c. Initialize fields.
<inf>: Remove field.
<reset>: New method.
* infrun.c (struct displaced_step_inferior_state): Move to
infrun.h.
(displaced_step_inferior_states): Remove.
(get_displaced_stepping_state): Adust.
(displaced_step_in_progress_any_inferior): Adjust.
(displaced_step_in_progress_thread): Adjust.
(displaced_step_in_progress): Adjust.
(add_displaced_stepping_state): Remove.
(get_displaced_step_closure_by_addr): Adjust.
(remove_displaced_stepping_state): Remove.
(infrun_inferior_exit): Call displaced_step_state.reset.
(use_displaced_stepping): Don't check for NULL.
(displaced_step_prepare_throw): Call
get_displaced_stepping_state.
(displaced_step_fixup): Don't check for NULL.
(prepare_for_detach): Don't check for NULL.
---
gdb/inferior.h | 3 ++
gdb/infrun.c | 129 ++++++-------------------------------------------
gdb/infrun.h | 47 ++++++++++++++++++
3 files changed, 66 insertions(+), 113 deletions(-)
Comments
On 11/23/2018 06:24 PM, Simon Marchi wrote:
> This patch moves the per-inferior data related to displaced stepping to
> be directly in the inferior structure, rather than in a container on the
> side.
>
> On notable difference is that previously, we deleted the state on
> inferior exit, which guaranteed a clean state if re-using the inferior
> for a new run or attach. We now need to reset the state manually.
>
Thanks. This LGTM. See a couple nits below.
>
> /* Returns true if any inferior has a thread doing a displaced
> @@ -1531,9 +1490,11 @@ get_displaced_stepping_state (inferior *inf)
> static bool
> displaced_step_in_progress_any_inferior ()
> {
> - for (auto *state : displaced_step_inferior_states)
> + inferior *i;
> +
> + ALL_INFERIORS (i)
This won't compile in current master. :-)
Use
for (inferior *inf : all_inferiors ())
> {
> - if (state->step_thread != nullptr)
> + if (i->displaced_step_state.step_thread != nullptr)
> return true;
> }
> if (debug_infrun)
> diff --git a/gdb/infrun.h b/gdb/infrun.h
> index a701f0ca47f..81b3c326163 100644
> --- a/gdb/infrun.h
> +++ b/gdb/infrun.h
> @@ -258,4 +258,51 @@ struct buf_displaced_step_closure : displaced_step_closure
> gdb::byte_vector buf;
> };
>
> +/* Per-inferior displaced stepping state. */
> +struct displaced_step_inferior_state
> +{
> + /* Put this object back in its original state. s*/
Typo: the "s" at the end.
> +/* Per-inferior displaced stepping state. */
> +struct displaced_step_inferior_state
> +{
> + /* Put this object back in its original state. s*/
> + void reset ()
> + {
> + /* These should have been cleaned after the last displaced step
> + operation, so if there are still set, it's a bug. */
> + gdb_assert (step_thread == nullptr);
> + gdb_assert (step_closure == nullptr);
> +
> + failed_before = 0;
> + step_gdbarch = nullptr;
> + step_original = 0;
> + step_copy = 0;
> +
> + if (step_saved_copy != nullptr)
> + {
> + xfree (step_saved_copy);
> + step_saved_copy = nullptr;
> + }
> + }
> +
> + /* True if preparing a displaced step ever failed. If so, we won't
> + try displaced stepping for this inferior again. */
> + int failed_before = 0;
> +
> + /* If this is not nullptr, this is the thread carrying out a
> + displaced single-step in process PID. This thread's state will
> + require fixing up once it has completed its step. */
> + thread_info *step_thread = nullptr;
> +
> + /* The architecture the thread had when we stepped it. */
> + gdbarch *step_gdbarch = nullptr;
> +
> + /* The closure provided gdbarch_displaced_step_copy_insn, to be used
> + for post-step cleanup. */
> + displaced_step_closure *step_closure = nullptr;
> +
> + /* The address of the original instruction, and the copy we
> + made. */
> + CORE_ADDR step_original = 0, step_copy = 0;
> +
> + /* Saved contents of copy area. */
> + gdb_byte *step_saved_copy = nullptr;
I'm fine with this, but I thought I'd mention another possibility,
which is to not initialize the field in-class, but instead add
a ctor that calls reset(), thus keeping the initializations
all in the same place.
Thanks,
Pedro Alves
@@ -503,6 +503,9 @@ public:
this gdbarch. */
struct gdbarch *gdbarch = NULL;
+ /* Data related to displaced stepping. */
+ displaced_step_inferior_state displaced_step_state;
+
/* Per inferior data-pointers required by other GDB modules. */
REGISTRY_FIELDS;
};
@@ -1476,53 +1476,12 @@ step_over_info_valid_p (void)
displaced_step_closure::~displaced_step_closure () = default;
-/* Per-inferior displaced stepping state. */
-struct displaced_step_inferior_state
-{
- /* The process this displaced step state refers to. */
- inferior *inf;
-
- /* True if preparing a displaced step ever failed. If so, we won't
- try displaced stepping for this inferior again. */
- int failed_before;
-
- /* If this is not nullptr, this is the thread carrying out a
- displaced single-step in process PID. This thread's state will
- require fixing up once it has completed its step. */
- thread_info *step_thread;
-
- /* The architecture the thread had when we stepped it. */
- struct gdbarch *step_gdbarch;
-
- /* The closure provided gdbarch_displaced_step_copy_insn, to be used
- for post-step cleanup. */
- struct displaced_step_closure *step_closure;
-
- /* The address of the original instruction, and the copy we
- made. */
- CORE_ADDR step_original, step_copy;
-
- /* Saved contents of copy area. */
- gdb_byte *step_saved_copy;
-};
-
-/* The list of states of processes involved in displaced stepping
- presently. */
-static std::forward_list<displaced_step_inferior_state *>
- displaced_step_inferior_states;
-
/* Get the displaced stepping state of process PID. */
static displaced_step_inferior_state *
get_displaced_stepping_state (inferior *inf)
{
- for (auto *state : displaced_step_inferior_states)
- {
- if (state->inf == inf)
- return state;
- }
-
- return nullptr;
+ return &inf->displaced_step_state;
}
/* Returns true if any inferior has a thread doing a displaced
@@ -1531,9 +1490,11 @@ get_displaced_stepping_state (inferior *inf)
static bool
displaced_step_in_progress_any_inferior ()
{
- for (auto *state : displaced_step_inferior_states)
+ inferior *i;
+
+ ALL_INFERIORS (i)
{
- if (state->step_thread != nullptr)
+ if (i->displaced_step_state.step_thread != nullptr)
return true;
}
@@ -1546,13 +1507,9 @@ displaced_step_in_progress_any_inferior ()
static int
displaced_step_in_progress_thread (thread_info *thread)
{
- struct displaced_step_inferior_state *displaced;
-
gdb_assert (thread != NULL);
- displaced = get_displaced_stepping_state (thread->inf);
-
- return (displaced != NULL && displaced->step_thread == thread);
+ return get_displaced_stepping_state (thread->inf)->step_thread == thread;
}
/* Return true if process PID has a thread doing a displaced step. */
@@ -1560,34 +1517,7 @@ displaced_step_in_progress_thread (thread_info *thread)
static int
displaced_step_in_progress (inferior *inf)
{
- struct displaced_step_inferior_state *displaced;
-
- displaced = get_displaced_stepping_state (inf);
- if (displaced != NULL && displaced->step_thread != nullptr)
- return 1;
-
- return 0;
-}
-
-/* Add a new displaced stepping state for process PID to the displaced
- stepping state list, or return a pointer to an already existing
- entry, if it already exists. Never returns NULL. */
-
-static displaced_step_inferior_state *
-add_displaced_stepping_state (inferior *inf)
-{
- displaced_step_inferior_state *state
- = get_displaced_stepping_state (inf);
-
- if (state != nullptr)
- return state;
-
- state = XCNEW (struct displaced_step_inferior_state);
- state->inf = inf;
-
- displaced_step_inferior_states.push_front (state);
-
- return state;
+ return get_displaced_stepping_state (inf)->step_thread != nullptr;
}
/* If inferior is in displaced stepping, and ADDR equals to starting address
@@ -1597,42 +1527,21 @@ add_displaced_stepping_state (inferior *inf)
struct displaced_step_closure*
get_displaced_step_closure_by_addr (CORE_ADDR addr)
{
- struct displaced_step_inferior_state *displaced
+ displaced_step_inferior_state *displaced
= get_displaced_stepping_state (current_inferior ());
/* If checking the mode of displaced instruction in copy area. */
- if (displaced != NULL
- && displaced->step_thread != nullptr
+ if (displaced->step_thread != nullptr
&& displaced->step_copy == addr)
return displaced->step_closure;
return NULL;
}
-/* Remove the displaced stepping state of process PID. */
-
-static void
-remove_displaced_stepping_state (inferior *inf)
-{
- gdb_assert (inf != nullptr);
-
- displaced_step_inferior_states.remove_if
- ([inf] (displaced_step_inferior_state *state)
- {
- if (state->inf == inf)
- {
- xfree (state);
- return true;
- }
- else
- return false;
- });
-}
-
static void
infrun_inferior_exit (struct inferior *inf)
{
- remove_displaced_stepping_state (inf);
+ inf->displaced_step_state.reset ();
}
/* If ON, and the architecture supports it, GDB will use displaced
@@ -1669,17 +1578,15 @@ use_displaced_stepping (struct thread_info *tp)
{
struct regcache *regcache = get_thread_regcache (tp);
struct gdbarch *gdbarch = regcache->arch ();
- struct displaced_step_inferior_state *displaced_state;
-
- displaced_state = get_displaced_stepping_state (tp->inf);
+ displaced_step_inferior_state *displaced_state
+ = get_displaced_stepping_state (tp->inf);
return (((can_use_displaced_stepping == AUTO_BOOLEAN_AUTO
&& target_is_non_stop_p ())
|| can_use_displaced_stepping == AUTO_BOOLEAN_TRUE)
&& gdbarch_displaced_step_copy_insn_p (gdbarch)
&& find_record_target () == NULL
- && (displaced_state == NULL
- || !displaced_state->failed_before));
+ && !displaced_state->failed_before);
}
/* Clean out any stray displaced stepping state. */
@@ -1741,7 +1648,6 @@ displaced_step_prepare_throw (thread_info *tp)
CORE_ADDR original, copy;
ULONGEST len;
struct displaced_step_closure *closure;
- struct displaced_step_inferior_state *displaced;
int status;
/* We should never reach this function if the architecture does not
@@ -1760,7 +1666,8 @@ displaced_step_prepare_throw (thread_info *tp)
/* We have to displaced step one thread at a time, as we only have
access to a single scratch space per inferior. */
- displaced = add_displaced_stepping_state (tp->inf);
+ displaced_step_inferior_state *displaced
+ = get_displaced_stepping_state (tp->inf);
if (displaced->step_thread != nullptr)
{
@@ -1953,10 +1860,6 @@ displaced_step_fixup (thread_info *event_thread, enum gdb_signal signal)
= get_displaced_stepping_state (event_thread->inf);
int ret;
- /* Was any thread of this process doing a displaced step? */
- if (displaced == NULL)
- return 0;
-
/* Was this event for the thread we displaced? */
if (displaced->step_thread != event_thread)
return 0;
@@ -3577,7 +3480,7 @@ prepare_for_detach (void)
/* Is any thread of this process displaced stepping? If not,
there's nothing else to do. */
- if (displaced == NULL || displaced->step_thread == nullptr)
+ if (displaced->step_thread == nullptr)
return;
if (debug_infrun)
@@ -258,4 +258,51 @@ struct buf_displaced_step_closure : displaced_step_closure
gdb::byte_vector buf;
};
+/* Per-inferior displaced stepping state. */
+struct displaced_step_inferior_state
+{
+ /* Put this object back in its original state. s*/
+ void reset ()
+ {
+ /* These should have been cleaned after the last displaced step
+ operation, so if there are still set, it's a bug. */
+ gdb_assert (step_thread == nullptr);
+ gdb_assert (step_closure == nullptr);
+
+ failed_before = 0;
+ step_gdbarch = nullptr;
+ step_original = 0;
+ step_copy = 0;
+
+ if (step_saved_copy != nullptr)
+ {
+ xfree (step_saved_copy);
+ step_saved_copy = nullptr;
+ }
+ }
+
+ /* True if preparing a displaced step ever failed. If so, we won't
+ try displaced stepping for this inferior again. */
+ int failed_before = 0;
+
+ /* If this is not nullptr, this is the thread carrying out a
+ displaced single-step in process PID. This thread's state will
+ require fixing up once it has completed its step. */
+ thread_info *step_thread = nullptr;
+
+ /* The architecture the thread had when we stepped it. */
+ gdbarch *step_gdbarch = nullptr;
+
+ /* The closure provided gdbarch_displaced_step_copy_insn, to be used
+ for post-step cleanup. */
+ displaced_step_closure *step_closure = nullptr;
+
+ /* The address of the original instruction, and the copy we
+ made. */
+ CORE_ADDR step_original = 0, step_copy = 0;
+
+ /* Saved contents of copy area. */
+ gdb_byte *step_saved_copy = nullptr;
+};
+
#endif /* INFRUN_H */