[PATCH 2/2] "catch catch/throw/rethrow", breakpoint -> catchpoint
Pedro Alves
palves@redhat.com
Fri Jul 5 16:01:00 GMT 2019
Currently, with:
(gdb) catch catch
Catchpoint 1 (catch)
(gdb) catch throw
Catchpoint 2 (throw)
(gdb) catch rethrow
Catchpoint 3 (rethrow)
You get:
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000000000b122af exception catch
2 breakpoint keep y 0x0000000000b1288d exception throw
3 breakpoint keep y 0x0000000000b12931 exception rethrow
I think it doesn't make much sense usability-wise, to show a
catchpoint as a breakpoint. The fact that GDB sets a breakpoint at
some magic address in the C++ run time is an implementation detail,
IMO. And as seen in the previous patch, such a catchpoint can end up
with more than one location/address even, so showing a single address
isn't entirely accurate.
This commit hides the addresses from view, and makes GDB show
"catchpoint" for type as well:
(gdb) info breakpoints
Num Type Disp Enb Address What
1 catchpoint keep y exception catch
2 catchpoint keep y exception throw
3 catchpoint keep y exception rethrow
This comment in the code seems telling:
/* We need to reset 'type' in order for code in breakpoint.c to do
the right thing. */
cp->type = bp_breakpoint;
It kind of suggests that the reason catchpoints end up shown as
breakpoints was that it was easier to implement them that way, rather
than a desired property.
This commit fixes things up to make it possible to have bp_catch
breakpoints have software/hardware breakpoint locations, thus
eliminating the need for that hack:
- redo breakpoint_address_is_meaningful in terms of the location's
type rather than breakpoint type.
- teach bpstat_what about stepping over the catchpoint locations.
- install a allocate_location method for "catch catch/throw/rethrow",
one that forces the location type.
Note that this also reverts the gdb hunk from:
commit 2a8be20359dba9cc684fd3ffa222d985399f3b18
Commit: Tom Tromey <tom@tromey.com>
CommitDate: Sat Oct 6 22:17:45 2018 -0600
Fix Python gdb.Breakpoint.location crash
because now "catch throw" catchpoints hit the
if (obj->bp->type != bp_breakpoint)
Py_RETURN_NONE;
check above, and, adjusts the testcase to no longer expect to see the
catchpoint in the gdb.breakpoints() list.
(Note: might make sense to do the same to Ada exception catchpoints.)
gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <palves@redhat.com>
* break-catch-throw.c (print_one_exception_catchpoint): Skip the
"addr" field.
(allocate_location_exception_catchpoint): New.
(handle_gnu_v3_exceptions): Don't reset 'type' to bp_breakpoint.
(initialize_throw_catchpoint_ops): Install
allocate_location_exception_catchpoint as allocate_location
method.
* breakpoint.c (bpstat_what) <bp_catch>: Set action to
BPSTAT_WHAT_SINGLE if not stopping and the location's type is not
bp_loc_other.
(breakpoint_address_is_meaningful): Delete.
(bl_address_is_meaningful): New.
(breakpoint_locations_match): Adjust comment.
(bp_location_from_bp_type): New, factored out of...
(bp_location::bp_location(breakpoint *)): ... this.
(bp_location::bp_location(breakpoint *, bp_loc_type)): New,
factored out of...
(bp_location::bp_location(breakpoint *)): ... this. Reimplement.
(bp_loc_is_permanent): Use bl_address_is_meaningful instead of
breakpoint_address_is_meaningful.
(bp_locations_compare): Adjust comment.
(update_global_location_list): Use bl_address_is_meaningful
instead of breakpoint_address_is_meaningful.
* breakpoint.h (bp_location::bp_location(breakpoint *)): New
explicit.
(bp_location::bp_location(breakpoint *, bp_loc_type)): Declare.
* python/py-breakpoint.c (bppy_get_location): No longer check
whether location is null.
gdb/testsuite/ChangeLog:
yyyy-mm-dd Pedro Alves <palves@redhat.com>
* gdb.cp/catch-multi-stdlib.exp: Adjust expected "info
breakpoints" output.
* gdb.cp/exception.exp: Adjust expected "info breakpoints" output.
* gdb.python/py-breakpoint.exp: No longer expect that "catch
throw" creates breakpoint.
---
gdb/break-catch-throw.c | 25 +++---
gdb/breakpoint.c | 108 +++++++++++++------------
gdb/breakpoint.h | 7 +-
gdb/python/py-breakpoint.c | 8 +-
gdb/testsuite/gdb.cp/except-multi-location.exp | 6 +-
gdb/testsuite/gdb.cp/exception.exp | 18 +----
gdb/testsuite/gdb.python/py-breakpoint.exp | 5 +-
7 files changed, 84 insertions(+), 93 deletions(-)
diff --git a/gdb/break-catch-throw.c b/gdb/break-catch-throw.c
index 107ac74f5cc..c0b3eec63d1 100644
--- a/gdb/break-catch-throw.c
+++ b/gdb/break-catch-throw.c
@@ -249,18 +249,10 @@ print_one_exception_catchpoint (struct breakpoint *b,
enum exception_event_kind kind = classify_exception_breakpoint (b);
get_user_print_options (&opts);
+
if (opts.addressprint)
- {
- annotate_field (4);
- if (b->loc == NULL || b->loc->shlib_disabled)
- uiout->field_string ("addr", "<PENDING>");
- else
- uiout->field_core_addr ("addr",
- b->loc->gdbarch, b->loc->address);
- }
+ uiout->field_skip ("addr");
annotate_field (5);
- if (b->loc)
- *last_loc = b->loc;
switch (kind)
{
@@ -344,6 +336,15 @@ print_recreate_exception_catchpoint (struct breakpoint *b,
print_recreate_thread (b, fp);
}
+/* Implement the "allocate_location" breakpoint_ops method for throw
+ and catch catchpoints. */
+
+static bp_location *
+allocate_location_exception_catchpoint (breakpoint *self)
+{
+ return new bp_location (self, bp_loc_software_breakpoint);
+}
+
static void
handle_gnu_v3_exceptions (int tempflag, std::string &&except_rx,
const char *cond_string,
@@ -361,9 +362,6 @@ handle_gnu_v3_exceptions (int tempflag, std::string &&except_rx,
init_catchpoint (cp.get (), get_current_arch (), tempflag, cond_string,
&gnu_v3_exception_catchpoint_ops);
- /* We need to reset 'type' in order for code in breakpoint.c to do
- the right thing. */
- cp->type = bp_breakpoint;
cp->kind = ex_event;
cp->exception_rx = std::move (except_rx);
cp->pattern = std::move (pattern);
@@ -521,6 +519,7 @@ initialize_throw_catchpoint_ops (void)
ops->print_recreate = print_recreate_exception_catchpoint;
ops->print_one_detail = print_one_detail_exception_catchpoint;
ops->check_status = check_status_exception_catchpoint;
+ ops->allocate_location = allocate_location_exception_catchpoint;
}
void
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index d508921fdc5..36500758257 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -5603,8 +5603,10 @@ bpstat_what (bpstat bs_head)
}
else
{
- /* There was a catchpoint, but we're not stopping.
- This requires no further action. */
+ /* Some catchpoints are implemented with breakpoints.
+ For those, we need to step over the breakpoint. */
+ if (bs->bp_location_at->loc_type != bp_loc_other)
+ this_action = BPSTAT_WHAT_SINGLE;
}
break;
case bp_jit_event:
@@ -6686,27 +6688,21 @@ describe_other_breakpoints (struct gdbarch *gdbarch,
}
-/* Return true iff it is meaningful to use the address member of
- BPT locations. For some breakpoint types, the locations' address members
- are irrelevant and it makes no sense to attempt to compare them to other
- addresses (or use them for any other purpose either).
-
- More specifically, each of the following breakpoint types will
- always have a zero valued location address and we don't want to mark
- breakpoints of any of these types to be a duplicate of an actual
- breakpoint location at address zero:
-
- bp_watchpoint
- bp_catchpoint
+/* Return true iff it is meaningful to use the address member of LOC.
+ For some breakpoint types, the locations' address members are
+ irrelevant and it makes no sense to attempt to compare them to
+ other addresses (or use them for any other purpose either).
-*/
+ More specifically, software watchpoints and catchpoints that are
+ not backed by breakpoints always have a zero valued location
+ address and we don't want to mark breakpoints of any of these types
+ to be a duplicate of an actual breakpoint location at address
+ zero. */
-static int
-breakpoint_address_is_meaningful (struct breakpoint *bpt)
+static bool
+bl_address_is_meaningful (bp_location *loc)
{
- enum bptype type = bpt->type;
-
- return (type != bp_watchpoint && type != bp_catchpoint);
+ return loc->loc_type != bp_loc_other;
}
/* Assuming LOC1 and LOC2's owners are hardware watchpoints, returns
@@ -6838,8 +6834,8 @@ tracepoint_locations_match (struct bp_location *loc1,
}
/* Assuming LOC1 and LOC2's types' have meaningful target addresses
- (breakpoint_address_is_meaningful), returns true if LOC1 and LOC2
- represent the same location. */
+ (bl_address_is_meaningful), returns true if LOC1 and LOC2 represent
+ the same location. */
static int
breakpoint_locations_match (struct bp_location *loc1,
@@ -6937,16 +6933,10 @@ adjust_breakpoint_address (struct gdbarch *gdbarch,
}
}
-bp_location::bp_location (breakpoint *owner)
+static bp_loc_type
+bp_location_from_bp_type (bptype type)
{
- bp_location *loc = this;
-
- loc->owner = owner;
- loc->cond_bytecode = NULL;
- loc->shlib_disabled = 0;
- loc->enabled = 1;
-
- switch (owner->type)
+ switch (type)
{
case bp_breakpoint:
case bp_single_step:
@@ -6972,30 +6962,44 @@ bp_location::bp_location (breakpoint *owner)
case bp_gnu_ifunc_resolver:
case bp_gnu_ifunc_resolver_return:
case bp_dprintf:
- loc->loc_type = bp_loc_software_breakpoint;
- mark_breakpoint_location_modified (loc);
- break;
+ return bp_loc_software_breakpoint;
case bp_hardware_breakpoint:
- loc->loc_type = bp_loc_hardware_breakpoint;
- mark_breakpoint_location_modified (loc);
- break;
+ return bp_loc_hardware_breakpoint;
case bp_hardware_watchpoint:
case bp_read_watchpoint:
case bp_access_watchpoint:
- loc->loc_type = bp_loc_hardware_watchpoint;
- break;
+ return bp_loc_hardware_watchpoint;
case bp_watchpoint:
case bp_catchpoint:
case bp_tracepoint:
case bp_fast_tracepoint:
case bp_static_tracepoint:
- loc->loc_type = bp_loc_other;
- break;
+ return bp_loc_other;
default:
internal_error (__FILE__, __LINE__, _("unknown breakpoint type"));
}
+}
+
+bp_location::bp_location (breakpoint *owner, bp_loc_type type)
+{
+ this->owner = owner;
+ this->cond_bytecode = NULL;
+ this->shlib_disabled = 0;
+ this->enabled = 1;
+
+ this->loc_type = type;
- loc->refc = 1;
+ if (this->loc_type == bp_loc_software_breakpoint
+ || this->loc_type == bp_loc_hardware_breakpoint)
+ mark_breakpoint_location_modified (this);
+
+ this->refc = 1;
+}
+
+bp_location::bp_location (breakpoint *owner)
+ : bp_location::bp_location (owner,
+ bp_location_from_bp_type (owner->type))
+{
}
/* Allocate a struct bp_location. */
@@ -8643,11 +8647,12 @@ bp_loc_is_permanent (struct bp_location *loc)
{
gdb_assert (loc != NULL);
- /* If we have a catchpoint or a watchpoint, just return 0. We should not
- attempt to read from the addresses the locations of these breakpoint types
- point to. program_breakpoint_here_p, below, will attempt to read
+ /* If we have a non-breakpoint-backed catchpoint or a software
+ watchpoint, just return 0. We should not attempt to read from
+ the addresses the locations of these breakpoint types point to.
+ program_breakpoint_here_p, below, will attempt to read
memory. */
- if (!breakpoint_address_is_meaningful (loc->owner))
+ if (!bl_address_is_meaningful (loc))
return 0;
scoped_restore_current_pspace_and_thread restore_pspace_thread;
@@ -11455,10 +11460,9 @@ breakpoint_auto_delete (bpstat bs)
/* A comparison function for bp_location AP and BP being interfaced to
qsort. Sort elements primarily by their ADDRESS (no matter what
- does breakpoint_address_is_meaningful say for its OWNER),
- secondarily by ordering first permanent elements and
- terciarily just ensuring the array is sorted stable way despite
- qsort being an unstable algorithm. */
+ bl_address_is_meaningful says), secondarily by ordering first
+ permanent elements and terciarily just ensuring the array is sorted
+ stable way despite qsort being an unstable algorithm. */
static int
bp_locations_compare (const void *ap, const void *bp)
@@ -11798,7 +11802,7 @@ update_global_location_list (enum ugll_insert_mode insert_mode)
this one from the target. */
/* OLD_LOC comes from existing struct breakpoint. */
- if (breakpoint_address_is_meaningful (old_loc->owner))
+ if (bl_address_is_meaningful (old_loc))
{
for (loc2p = locp;
(loc2p < bp_locations + bp_locations_count
@@ -11938,7 +11942,7 @@ update_global_location_list (enum ugll_insert_mode insert_mode)
b = loc->owner;
if (!unduplicated_should_be_inserted (loc)
- || !breakpoint_address_is_meaningful (b)
+ || !bl_address_is_meaningful (loc)
/* Don't detect duplicate for tracepoint locations because they are
never duplicated. See the comments in field `duplicate' of
`struct bp_location'. */
diff --git a/gdb/breakpoint.h b/gdb/breakpoint.h
index 75f19785cb1..6e9a35e82de 100644
--- a/gdb/breakpoint.h
+++ b/gdb/breakpoint.h
@@ -316,7 +316,12 @@ class bp_location
public:
bp_location () = default;
- bp_location (breakpoint *owner);
+ /* Construct a bp_location with the type inferred from OWNER's
+ type. */
+ explicit bp_location (breakpoint *owner);
+
+ /* Construct a bp_location with type TYPE. */
+ bp_location (breakpoint *owner, bp_loc_type type);
virtual ~bp_location ();
diff --git a/gdb/python/py-breakpoint.c b/gdb/python/py-breakpoint.c
index 88cd7de3343..698d91e9d32 100644
--- a/gdb/python/py-breakpoint.c
+++ b/gdb/python/py-breakpoint.c
@@ -379,7 +379,6 @@ bppy_set_hit_count (PyObject *self, PyObject *newvalue, void *closure)
static PyObject *
bppy_get_location (PyObject *self, void *closure)
{
- const char *str;
gdbpy_breakpoint_object *obj = (gdbpy_breakpoint_object *) self;
BPPY_REQUIRE_VALID (obj);
@@ -387,12 +386,7 @@ bppy_get_location (PyObject *self, void *closure)
if (obj->bp->type != bp_breakpoint)
Py_RETURN_NONE;
- struct event_location *location = obj->bp->location.get ();
- /* "catch throw" makes a breakpoint of type bp_breakpoint that does
- not have a location. */
- if (location == nullptr)
- Py_RETURN_NONE;
- str = event_location_to_string (location);
+ const char *str = event_location_to_string (obj->bp->location.get ());
if (! str)
str = "";
return host_string_to_python_string (str).release ();
diff --git a/gdb/testsuite/gdb.cp/except-multi-location.exp b/gdb/testsuite/gdb.cp/except-multi-location.exp
index 60d6d0b9351..1258d893afb 100644
--- a/gdb/testsuite/gdb.cp/except-multi-location.exp
+++ b/gdb/testsuite/gdb.cp/except-multi-location.exp
@@ -74,9 +74,9 @@ proc test_multi_libstdcpp {static_bin static_lib} {
set ws "\[ \t\]*"
gdb_test "info breakpoints" \
[multi_line \
- "${decimal}${ws}breakpoint${ws}keep${ws}y${ws}${hex}${ws}exception catch" \
- "${decimal}${ws}breakpoint${ws}keep${ws}y${ws}${hex}${ws}exception throw" \
- "${decimal}${ws}breakpoint${ws}keep${ws}y${ws}${hex}${ws}exception rethrow"]
+ "${decimal}${ws}catchpoint${ws}keep${ws}y${ws}exception catch" \
+ "${decimal}${ws}catchpoint${ws}keep${ws}y${ws}exception throw" \
+ "${decimal}${ws}catchpoint${ws}keep${ws}y${ws}exception rethrow"]
}
# Try different static/not-static combinations.
diff --git a/gdb/testsuite/gdb.cp/exception.exp b/gdb/testsuite/gdb.cp/exception.exp
index 4761de20e19..0be382ba98c 100644
--- a/gdb/testsuite/gdb.cp/exception.exp
+++ b/gdb/testsuite/gdb.cp/exception.exp
@@ -62,16 +62,10 @@ gdb_test "catch rethrow" "Catchpoint \[0-9\]+ \\(rethrow\\)" \
"catch rethrow (before inferior run)"
-# The catchpoints should be listed in the list of breakpoints.
-# In case of a statically linked test, we won't have a pending breakpoint.
-# Hence we allow for both an address or "<PENDING>". If we ever become able
-# to tell whether the target is linked statically or not, we can be more
-# precise and require exact output.
-set addr "\(<PENDING>|$hex\)"
set re_head "Num${ws}Type${ws}Disp${ws}Enb${ws}Address${ws}What"
-set re_2_bp "1${ws}breakpoint${ws}keep${ws}y${ws}$addr${ws}exception catch"
-set re_3_bp "2${ws}breakpoint${ws}keep${ws}y${ws}$addr${ws}exception throw"
-set re_4_bp "3${ws}breakpoint${ws}keep${ws}y${ws}$addr${ws}exception rethrow"
+set re_2_bp "1${ws}catchpoint${ws}keep${ws}y${ws}exception catch"
+set re_3_bp "2${ws}catchpoint${ws}keep${ws}y${ws}exception throw"
+set re_4_bp "3${ws}catchpoint${ws}keep${ws}y${ws}exception rethrow"
set name "info breakpoints (before inferior run)"
gdb_test_multiple "info breakpoints" $name {
@@ -100,12 +94,6 @@ if { !$ok } {
continue
}
-set addr "$hex"
-set re_head "Num${ws}Type${ws}Disp${ws}Enb${ws}Address${ws}What"
-set re_2_bp "1${ws}breakpoint${ws}keep${ws}y${ws}$addr${ws}exception catch"
-set re_3_bp "2${ws}breakpoint${ws}keep${ws}y${ws}$addr${ws}exception throw"
-set re_4_bp "3${ws}breakpoint${ws}keep${ws}y${ws}$addr${ws}exception rethrow"
-
set name "info breakpoints (after inferior run)"
gdb_test_multiple "info breakpoints" $name {
-re "$re_head${ws}$re_2_bp${ws}$re_3_bp${ws}$re_4_bp\r\n$gdb_prompt $" {
diff --git a/gdb/testsuite/gdb.python/py-breakpoint.exp b/gdb/testsuite/gdb.python/py-breakpoint.exp
index 241e7e6839e..625977c0ad4 100644
--- a/gdb/testsuite/gdb.python/py-breakpoint.exp
+++ b/gdb/testsuite/gdb.python/py-breakpoint.exp
@@ -619,8 +619,9 @@ proc_with_prefix test_bkpt_explicit_loc {} {
delete_breakpoints
gdb_test "catch throw" "Catchpoint .* \\(throw\\)"
- gdb_test "python print (gdb.breakpoints()\[0\].location)" None \
- "Examine location of catchpoint"
+ gdb_test "python print (gdb.breakpoints())" \
+ "\(\)" \
+ "catch throw is not a breakpoint"
}
proc_with_prefix test_bkpt_qualified {} {
--
2.14.5
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