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Place displaced step data directly in inferior structure 

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.

At the same time, I changed step_saved_copy to be a gdb::byte_vector, so
it is automatically freed on destruction (which should plug the leak
reported here [1]).

[1] https://sourceware.org/ml/gdb-patches/2018-11/msg00202.html

gdb/ChangeLog:

	* inferior.h (class inferior) <displaced_step_state>: New field.
	* infrun.h (struct displaced_step_state): Move here from
	infrun.c.  Initialize fields, add constructor.
	<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.
This commit is contained in:
Simon Marchi 2019-01-02 17:31:08 -05:00
parent e331924073
commit d20172fc53
4 changed files with 91 additions and 122 deletions
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24
gdb/ChangeLog
View File

@ -1,3 +1,27 @@
2019-01-02 Simon Marchi <simon.marchi@ericsson.com>
* inferior.h (class inferior) <displaced_step_state>: New field.
* infrun.h (struct displaced_step_state): Move here from
infrun.c. Initialize fields, add constructor.
<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.
2019-01-02 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* infcall.c (call_function_by_hand_dummy): cleanup/destroy sm

3
gdb/inferior.h
View File

@ -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;
};

142
gdb/infrun.c
View File

@ -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 +1490,9 @@ get_displaced_stepping_state (inferior *inf)
static bool
displaced_step_in_progress_any_inferior ()
{
for (auto *state : displaced_step_inferior_states)
for (inferior *i : all_inferiors ())
{
if (state->step_thread != nullptr)
if (i->displaced_step_state.step_thread != nullptr)
return true;
}
@ -1546,13 +1505,9 @@ 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 +1515,7 @@ 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 +1525,21 @@ 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 +1576,15 @@ 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. */
@ -1734,14 +1639,12 @@ displaced_step_dump_bytes (struct ui_file *file,
static int
displaced_step_prepare_throw (thread_info *tp)
{
struct cleanup *ignore_cleanups;
regcache *regcache = get_thread_regcache (tp);
struct gdbarch *gdbarch = regcache->arch ();
const address_space *aspace = regcache->aspace ();
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 +1663,8 @@ 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)
{
@ -1816,10 +1720,8 @@ displaced_step_prepare_throw (thread_info *tp)
}
/* Save the original contents of the copy area. */
displaced->step_saved_copy = (gdb_byte *) xmalloc (len);
ignore_cleanups = make_cleanup (free_current_contents,
&displaced->step_saved_copy);
status = target_read_memory (copy, displaced->step_saved_copy, len);
displaced->step_saved_copy.resize (len);
status = target_read_memory (copy, displaced->step_saved_copy.data (), len);
if (status != 0)
throw_error (MEMORY_ERROR,
_("Error accessing memory address %s (%s) for "
@ -1830,7 +1732,7 @@ displaced_step_prepare_throw (thread_info *tp)
fprintf_unfiltered (gdb_stdlog, "displaced: saved %s: ",
paddress (gdbarch, copy));
displaced_step_dump_bytes (gdb_stdlog,
displaced->step_saved_copy,
displaced->step_saved_copy.data (),
len);
};
@ -1841,7 +1743,6 @@ displaced_step_prepare_throw (thread_info *tp)
/* The architecture doesn't know how or want to displaced step
this instruction or instruction sequence. Fallback to
stepping over the breakpoint in-line. */
do_cleanups (ignore_cleanups);
return -1;
}
@ -1853,7 +1754,8 @@ displaced_step_prepare_throw (thread_info *tp)
displaced->step_original = original;
displaced->step_copy = copy;
make_cleanup (displaced_step_clear_cleanup, displaced);
cleanup *ignore_cleanups
= make_cleanup (displaced_step_clear_cleanup, displaced);
/* Resume execution at the copy. */
regcache_write_pc (regcache, copy);
@ -1931,7 +1833,7 @@ displaced_step_restore (struct displaced_step_inferior_state *displaced,
ULONGEST len = gdbarch_max_insn_length (displaced->step_gdbarch);
write_memory_ptid (ptid, displaced->step_copy,
displaced->step_saved_copy, len);
displaced->step_saved_copy.data (), len);
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: restored %s %s\n",
target_pid_to_str (ptid),
@ -1953,10 +1855,6 @@ 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 +3475,7 @@ 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)

44
gdb/infrun.h
View File

@ -258,4 +258,48 @@ struct buf_displaced_step_closure : displaced_step_closure
gdb::byte_vector buf;
};
/* Per-inferior displaced stepping state. */
struct displaced_step_inferior_state
{
displaced_step_inferior_state ()
{
reset ();
}
/* Put this object back in its original state. */
void reset ()
{
failed_before = 0;
step_thread = nullptr;
step_gdbarch = nullptr;
step_closure = nullptr;
step_original = 0;
step_copy = 0;
step_saved_copy.clear ();
}
/* 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. */
gdbarch *step_gdbarch;
/* The closure provided gdbarch_displaced_step_copy_insn, to be used
for post-step cleanup. */
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_vector step_saved_copy;
};
#endif /* INFRUN_H */