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Make bp_location derive from refcounted_object

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This changes bp_location to derive from refcounted_object, introduces
a ref_ptr specialization for this type, and then changes
bpstats::bp_location_at to use that specialization.  This removes some
manual reference counting and simplifies the code.

gdb/ChangeLog
2020-12-11  Tom Tromey  <tom@tromey.com>

	* inline-frame.c (stopped_by_user_bp_inline_frame): Update.
	* ada-lang.c (check_status_exception): Update.
	* breakpoint.c (free_bp_location): Remove.
	(decref_bp_location): Use bp_location_ref_policy.
	(bpstats::bpstats): Don't call incref_bp_location.
	(bpstats::~bpstats): Remove.
	(bpstats::bpstats): Update.
	(bpstat_check_watchpoint, bpstat_check_breakpoint_conditions)
	(bp_location::bp_location): Update.
	(incref_bp_location): Remove.
	(bkpt_print_it): Update.
	* breakpoint.h (class bp_location): Derive from
	refcounted_object.
	(struct bpstats): Remove destructor.
	<bp_location_at>: Now a bp_location_ref_ptr.
	<refc>: Remove.
	(bp_location_ref_ptr): New typedef.
	(struct bp_location_ref_policy): New.
This commit is contained in:
Tom Tromey
2020-12-11 09:21:53 -07:00
parent bfcb9db853
commit b6433ede07
5 changed files with 53 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
gdb/ChangeLog
View File

@@ -1,3 +1,24 @@
2020-12-11 Tom Tromey <tom@tromey.com>
* inline-frame.c (stopped_by_user_bp_inline_frame): Update.
* ada-lang.c (check_status_exception): Update.
* breakpoint.c (free_bp_location): Remove.
(decref_bp_location): Use bp_location_ref_policy.
(bpstats::bpstats): Don't call incref_bp_location.
(bpstats::~bpstats): Remove.
(bpstats::bpstats): Update.
(bpstat_check_watchpoint, bpstat_check_breakpoint_conditions)
(bp_location::bp_location): Update.
(incref_bp_location): Remove.
(bkpt_print_it): Update.
* breakpoint.h (class bp_location): Derive from
refcounted_object.
(struct bpstats): Remove destructor.
<bp_location_at>: Now a bp_location_ref_ptr.
<refc>: Remove.
(bp_location_ref_ptr): New typedef.
(struct bp_location_ref_policy): New.
2020-12-11 Tom Tromey <tom@tromey.com>
* thread.c (class scoped_inc_dec_ref): Remove.

2
gdb/ada-lang.c
View File

@@ -12255,7 +12255,7 @@ should_stop_exception (const struct bp_location *bl)
static void
check_status_exception (bpstat bs)
{
bs->stop = should_stop_exception (bs->bp_location_at);
bs->stop = should_stop_exception (bs->bp_location_at.get ());
}
/* Implement the PRINT_IT method in the breakpoint_ops structure

43
gdb/breakpoint.c
View File

@@ -172,8 +172,6 @@ static int hw_watchpoint_used_count_others (struct breakpoint *except,
static void enable_breakpoint_disp (struct breakpoint *, enum bpdisp,
int count);
static void free_bp_location (struct bp_location *loc);
static void incref_bp_location (struct bp_location *loc);
static void decref_bp_location (struct bp_location **loc);
static struct bp_location *allocate_bp_location (struct breakpoint *bpt);
@@ -4242,15 +4240,6 @@ is_catchpoint (struct breakpoint *b)
return (b->type == bp_catchpoint);
}
/* Frees any storage that is part of a bpstat. Does not walk the
'next' chain. */
bpstats::~bpstats ()
{
if (bp_location_at != NULL)
decref_bp_location (&bp_location_at);
}
/* Clear a bpstat so that it says we are not at any breakpoint.
Also free any storage that is part of a bpstat. */
@@ -4283,7 +4272,6 @@ bpstats::bpstats (const bpstats &other)
{
if (other.old_val != NULL)
old_val = release_value (value_copy (other.old_val.get ()));
incref_bp_location (bp_location_at);
}
/* Return a copy of a bpstat. Like "bs1 = bs2" but all storage that
@@ -4768,21 +4756,19 @@ breakpoint_cond_eval (expression *exp)
bpstats::bpstats (struct bp_location *bl, bpstat **bs_link_pointer)
: next (NULL),
bp_location_at (bl),
bp_location_at (bp_location_ref_ptr::new_reference (bl)),
breakpoint_at (bl->owner),
commands (NULL),
print (0),
stop (0),
print_it (print_it_normal)
{
incref_bp_location (bl);
**bs_link_pointer = this;
*bs_link_pointer = &next;
}
bpstats::bpstats ()
: next (NULL),
bp_location_at (NULL),
breakpoint_at (NULL),
commands (NULL),
print (0),
@@ -5060,7 +5046,7 @@ bpstat_check_watchpoint (bpstat bs)
struct watchpoint *b;
/* BS is built for existing struct breakpoint. */
bl = bs->bp_location_at;
bl = bs->bp_location_at.get ();
gdb_assert (bl != NULL);
b = (struct watchpoint *) bs->breakpoint_at;
gdb_assert (b != NULL);
@@ -5236,7 +5222,7 @@ bpstat_check_breakpoint_conditions (bpstat bs, thread_info *thread)
gdb_assert (bs->stop);
/* BS is built for existing struct breakpoint. */
bl = bs->bp_location_at;
bl = bs->bp_location_at.get ();
gdb_assert (bl != NULL);
b = bs->breakpoint_at;
gdb_assert (b != NULL);
@@ -7101,7 +7087,7 @@ bp_location::bp_location (breakpoint *owner, bp_loc_type type)
|| this->loc_type == bp_loc_hardware_breakpoint)
mark_breakpoint_location_modified (this);
this->refc = 1;
incref ();
}
bp_location::bp_location (breakpoint *owner)
@@ -7118,30 +7104,13 @@ allocate_bp_location (struct breakpoint *bpt)
return bpt->ops->allocate_location (bpt);
}
static void
free_bp_location (struct bp_location *loc)
{
delete loc;
}
/* Increment reference count. */
static void
incref_bp_location (struct bp_location *bl)
{
++bl->refc;
}
/* Decrement reference count. If the reference count reaches 0,
destroy the bp_location. Sets *BLP to NULL. */
static void
decref_bp_location (struct bp_location **blp)
{
gdb_assert ((*blp)->refc > 0);
if (--(*blp)->refc == 0)
free_bp_location (*blp);
bp_location_ref_policy::decref (*blp);
*blp = NULL;
}
@@ -12680,7 +12649,7 @@ bkpt_print_it (bpstat bs)
gdb_assert (bs->bp_location_at != NULL);
bl = bs->bp_location_at;
bl = bs->bp_location_at.get ();
b = bs->breakpoint_at;
bp_temp = b->disposition == disp_del;

30
gdb/breakpoint.h
View File

@@ -29,6 +29,7 @@
#include <vector>
#include "gdbsupport/array-view.h"
#include "gdbsupport/function-view.h"
#include "gdbsupport/refcounted-object.h"
#include "cli/cli-script.h"
struct block;
@@ -311,7 +312,7 @@ enum bp_loc_type
bp_loc_other /* Miscellaneous... */
};
class bp_location
class bp_location : public refcounted_object
{
public:
bp_location () = default;
@@ -329,9 +330,6 @@ public:
the same parent breakpoint. */
bp_location *next = NULL;
/* The reference count. */
int refc = 0;
/* Type of this breakpoint location. */
bp_loc_type loc_type {};
@@ -510,6 +508,27 @@ public:
const struct objfile *objfile = NULL;
};
/* A policy class for bp_location reference counting. */
struct bp_location_ref_policy
{
static void incref (bp_location *loc)
{
loc->incref ();
}
static void decref (bp_location *loc)
{
gdb_assert (loc->refcount () > 0);
loc->decref ();
if (loc->refcount () == 0)
delete loc;
}
};
/* A gdb::ref_ptr that has been specialized for bp_location. */
typedef gdb::ref_ptr<bp_location, bp_location_ref_policy>
bp_location_ref_ptr;
/* The possible return values for print_bpstat, print_it_normal,
print_it_done, print_it_noop. */
enum print_stop_action
@@ -1130,7 +1149,6 @@ struct bpstats
{
bpstats ();
bpstats (struct bp_location *bl, bpstat **bs_link_pointer);
~bpstats ();
bpstats (const bpstats &);
bpstats &operator= (const bpstats &) = delete;
@@ -1155,7 +1173,7 @@ struct bpstats
What this means is that we should not (in most cases) follow
the `bpstat->bp_location->owner' link, but instead use the
`breakpoint_at' field below. */
struct bp_location *bp_location_at;
bp_location_ref_ptr bp_location_at;
/* Breakpoint that caused the stop. This is nullified if the
breakpoint ends up being deleted. See comments on

2
gdb/inline-frame.c
View File

@@ -313,7 +313,7 @@ stopped_by_user_bp_inline_frame (const block *frame_block, bpstat stop_chain)
if (bpt != NULL
&& (user_breakpoint_p (bpt) || bpt->type == bp_until))
{
bp_location *loc = s->bp_location_at;
bp_location *loc = s->bp_location_at.get ();
enum bp_loc_type t = loc->loc_type;
if (t == bp_loc_software_breakpoint