binutils-gdb/gdb/break-catch-throw.c

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/* Everything about catch/throw catchpoints, for GDB.
Copyright (C) 1986-2013 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "arch-utils.h"
#include <ctype.h>
#include "breakpoint.h"
#include "gdbcmd.h"
#include "inferior.h"
#include "annotate.h"
#include "valprint.h"
#include "cli/cli-utils.h"
#include "completer.h"
#include "gdb_obstack.h"
#include "mi/mi-common.h"
#include "exceptions.h"
#include "linespec.h"
#include "probe.h"
#include "objfiles.h"
#include "cp-abi.h"
#include "gdb_regex.h"
#include "cp-support.h"
/* Enums for exception-handling support. */
enum exception_event_kind
{
EX_EVENT_THROW,
EX_EVENT_RETHROW,
EX_EVENT_CATCH
};
/* Each spot where we may place an exception-related catchpoint has
two names: the SDT probe point and the function name. This
structure holds both. */
struct exception_names
{
/* The name of the probe point to try, in the form accepted by
'parse_probes'. */
const char *probe;
/* The name of the corresponding function. */
const char *function;
};
/* Names of the probe points and functions on which to break. This is
indexed by exception_event_kind. */
static const struct exception_names exception_functions[] =
{
{ "-probe-stap libstdcxx:throw", "__cxa_throw" },
{ "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" },
{ "-probe-stap libstdcxx:catch", "__cxa_begin_catch" }
};
static struct breakpoint_ops gnu_v3_exception_catchpoint_ops;
/* The type of an exception catchpoint. */
struct exception_catchpoint
{
/* The base class. */
struct breakpoint base;
/* The kind of exception catchpoint. */
enum exception_event_kind kind;
/* If non-NULL, an xmalloc'd string holding the source form of the
regular expression to match against. */
char *exception_rx;
/* If non-NULL, an xmalloc'd, compiled regular expression which is
used to determine which exceptions to stop on. */
regex_t *pattern;
};
/* A helper function that fetches exception probe arguments. This
fills in *ARG0 (if non-NULL) and *ARG1 (which must be non-NULL).
It will throw an exception on any kind of failure. */
static void
fetch_probe_arguments (struct value **arg0, struct value **arg1)
{
struct frame_info *frame = get_selected_frame (_("No frame selected"));
CORE_ADDR pc = get_frame_pc (frame);
struct probe *pc_probe;
const struct sym_probe_fns *pc_probe_fns;
unsigned n_args;
pc_probe = find_probe_by_pc (pc);
if (pc_probe == NULL
|| strcmp (pc_probe->provider, "libstdcxx") != 0
|| (strcmp (pc_probe->name, "catch") != 0
&& strcmp (pc_probe->name, "throw") != 0
&& strcmp (pc_probe->name, "rethrow") != 0))
error (_("not stopped at a C++ exception catchpoint"));
Sanitize access to gdbarch on the SDT probe API (and fix ARM bug) This patch sanitizes the access to gdbarch made by various functions of the SDT probe API. Before this patch, gdbarch was being accessed via the probe's objfile; however, this proved to cause a bug on 32-bit ARM targets because during the parsing of the probe's arguments the code needed to access some pseudo-registers of the architecture, and this information is not fully correct on the objfile's gdbarch. Basically, the approach taken was to instead pass the current/selected frame to the parsing and evaluation functions, so that they can extract the gdbarch directly from the frame. It solved the ARM bug reported above, and also contributed to make the API cleaner. Tested on x86_64 and 32-bit ARM. 2013-12-11 Sergio Durigan Junior <sergiodj@redhat.com> * break-catch-throw.c (fetch_probe_arguments): Pass selected frame to get_probe_argument_count and evaluate_probe_argument. * probe.c (get_probe_argument_count): Adjust declaration to accept frame. Pass frame to probe_ops's get_probe_argument_count. (evaluate_probe_argument): Likewise, for evaluate_probe_argument. (probe_safe_evaluate_at_pc): Pass frame to get_probe_argument_count and evaluate_probe_argument. * probe.h (struct probe_ops) <get_probe_argument_count, evaluate_probe_argument>: Adjust declarations to accept frame. (get_probe_argument_count, evaluate_probe_argument): Likewise. * solib-svr4.c (solib_event_probe_action): Get current frame. Pass it to get_probe_argument_count. (svr4_handle_solib_event): Get current frame. Pass it to get_probe_argument_count and evaluate_probe_argument. * stap-probe.c (stap_parse_probe_arguments): Adjust declaration to accept gdbarch. Do not obtain it from the probe's objfile. (stap_get_probe_argument_count): Adjust declaration to accept frame. Obtain gdbarch from the frame. Call generic can_evaluate_probe_arguments. Pass gdbarch to stap_parse_probe_arguments. (stap_get_arg): Adjust declaration to accept gdbarch. Pass it to stap_parse_probe_arguments. (stap_evaluate_probe_argument): Adjust declaration to accept frame. Obtain gdbarch from the frame. Pass gdbarch to stap_get_arg. (stap_compile_to_ax): Pass agent_expr's gdbarch to stap_get_arg. (compute_probe_arg): Obtain gdbarch from frame. Pass frame to get_probe_argument_count and evaluate_probe_argument.
2013-12-11 09:53:25 +08:00
n_args = get_probe_argument_count (pc_probe, frame);
if (n_args < 2)
error (_("C++ exception catchpoint has too few arguments"));
if (arg0 != NULL)
Sanitize access to gdbarch on the SDT probe API (and fix ARM bug) This patch sanitizes the access to gdbarch made by various functions of the SDT probe API. Before this patch, gdbarch was being accessed via the probe's objfile; however, this proved to cause a bug on 32-bit ARM targets because during the parsing of the probe's arguments the code needed to access some pseudo-registers of the architecture, and this information is not fully correct on the objfile's gdbarch. Basically, the approach taken was to instead pass the current/selected frame to the parsing and evaluation functions, so that they can extract the gdbarch directly from the frame. It solved the ARM bug reported above, and also contributed to make the API cleaner. Tested on x86_64 and 32-bit ARM. 2013-12-11 Sergio Durigan Junior <sergiodj@redhat.com> * break-catch-throw.c (fetch_probe_arguments): Pass selected frame to get_probe_argument_count and evaluate_probe_argument. * probe.c (get_probe_argument_count): Adjust declaration to accept frame. Pass frame to probe_ops's get_probe_argument_count. (evaluate_probe_argument): Likewise, for evaluate_probe_argument. (probe_safe_evaluate_at_pc): Pass frame to get_probe_argument_count and evaluate_probe_argument. * probe.h (struct probe_ops) <get_probe_argument_count, evaluate_probe_argument>: Adjust declarations to accept frame. (get_probe_argument_count, evaluate_probe_argument): Likewise. * solib-svr4.c (solib_event_probe_action): Get current frame. Pass it to get_probe_argument_count. (svr4_handle_solib_event): Get current frame. Pass it to get_probe_argument_count and evaluate_probe_argument. * stap-probe.c (stap_parse_probe_arguments): Adjust declaration to accept gdbarch. Do not obtain it from the probe's objfile. (stap_get_probe_argument_count): Adjust declaration to accept frame. Obtain gdbarch from the frame. Call generic can_evaluate_probe_arguments. Pass gdbarch to stap_parse_probe_arguments. (stap_get_arg): Adjust declaration to accept gdbarch. Pass it to stap_parse_probe_arguments. (stap_evaluate_probe_argument): Adjust declaration to accept frame. Obtain gdbarch from the frame. Pass gdbarch to stap_get_arg. (stap_compile_to_ax): Pass agent_expr's gdbarch to stap_get_arg. (compute_probe_arg): Obtain gdbarch from frame. Pass frame to get_probe_argument_count and evaluate_probe_argument.
2013-12-11 09:53:25 +08:00
*arg0 = evaluate_probe_argument (pc_probe, 0, frame);
*arg1 = evaluate_probe_argument (pc_probe, 1, frame);
if ((arg0 != NULL && *arg0 == NULL) || *arg1 == NULL)
error (_("error computing probe argument at c++ exception catchpoint"));
}
/* A helper function that returns a value indicating the kind of the
exception catchpoint B. */
static enum exception_event_kind
classify_exception_breakpoint (struct breakpoint *b)
{
struct exception_catchpoint *cp = (struct exception_catchpoint *) b;
return cp->kind;
}
/* Implement the 'dtor' method. */
static void
dtor_exception_catchpoint (struct breakpoint *self)
{
struct exception_catchpoint *cp = (struct exception_catchpoint *) self;
xfree (cp->exception_rx);
if (cp->pattern != NULL)
regfree (cp->pattern);
bkpt_breakpoint_ops.dtor (self);
}
/* Implement the 'check_status' method. */
static void
check_status_exception_catchpoint (struct bpstats *bs)
{
struct exception_catchpoint *self
= (struct exception_catchpoint *) bs->breakpoint_at;
char *typename = NULL;
volatile struct gdb_exception e;
bkpt_breakpoint_ops.check_status (bs);
if (bs->stop == 0)
return;
if (self->pattern == NULL)
return;
TRY_CATCH (e, RETURN_MASK_ERROR)
{
struct value *typeinfo_arg;
char *canon;
fetch_probe_arguments (NULL, &typeinfo_arg);
typename = cplus_typename_from_type_info (typeinfo_arg);
canon = cp_canonicalize_string (typename);
if (canon != NULL)
{
xfree (typename);
typename = canon;
}
}
if (e.reason < 0)
exception_print (gdb_stderr, e);
else if (regexec (self->pattern, typename, 0, NULL, 0) != 0)
bs->stop = 0;
xfree (typename);
}
/* Implement the 're_set' method. */
static void
re_set_exception_catchpoint (struct breakpoint *self)
{
struct symtabs_and_lines sals = {0};
struct symtabs_and_lines sals_end = {0};
volatile struct gdb_exception e;
struct cleanup *cleanup;
enum exception_event_kind kind = classify_exception_breakpoint (self);
int pass;
for (pass = 0; sals.sals == NULL && pass < 2; ++pass)
{
TRY_CATCH (e, RETURN_MASK_ERROR)
{
char *spec;
if (pass == 0)
{
spec = ASTRDUP (exception_functions[kind].probe);
sals = parse_probes (&spec, NULL);
}
else
{
spec = ASTRDUP (exception_functions[kind].function);
self->ops->decode_linespec (self, &spec, &sals);
}
}
/* NOT_FOUND_ERROR just means the breakpoint will be pending, so
let it through. */
if (e.reason < 0 && e.error != NOT_FOUND_ERROR)
throw_exception (e);
}
cleanup = make_cleanup (xfree, sals.sals);
update_breakpoint_locations (self, sals, sals_end);
do_cleanups (cleanup);
}
static enum print_stop_action
print_it_exception_catchpoint (bpstat bs)
{
struct ui_out *uiout = current_uiout;
struct breakpoint *b = bs->breakpoint_at;
int bp_temp;
enum exception_event_kind kind = classify_exception_breakpoint (b);
annotate_catchpoint (b->number);
bp_temp = b->disposition == disp_del;
ui_out_text (uiout,
bp_temp ? "Temporary catchpoint "
: "Catchpoint ");
if (!ui_out_is_mi_like_p (uiout))
ui_out_field_int (uiout, "bkptno", b->number);
ui_out_text (uiout,
(kind == EX_EVENT_THROW ? " (exception thrown), "
: (kind == EX_EVENT_CATCH ? " (exception caught), "
: " (exception rethrown), ")));
if (ui_out_is_mi_like_p (uiout))
{
ui_out_field_string (uiout, "reason",
async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT));
ui_out_field_string (uiout, "disp", bpdisp_text (b->disposition));
ui_out_field_int (uiout, "bkptno", b->number);
}
return PRINT_SRC_AND_LOC;
}
static void
print_one_exception_catchpoint (struct breakpoint *b,
struct bp_location **last_loc)
{
struct value_print_options opts;
struct ui_out *uiout = current_uiout;
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)
ui_out_field_string (uiout, "addr", "<PENDING>");
else
ui_out_field_core_addr (uiout, "addr",
b->loc->gdbarch, b->loc->address);
}
annotate_field (5);
if (b->loc)
*last_loc = b->loc;
switch (kind)
{
case EX_EVENT_THROW:
ui_out_field_string (uiout, "what", "exception throw");
if (ui_out_is_mi_like_p (uiout))
ui_out_field_string (uiout, "catch-type", "throw");
break;
case EX_EVENT_RETHROW:
ui_out_field_string (uiout, "what", "exception rethrow");
if (ui_out_is_mi_like_p (uiout))
ui_out_field_string (uiout, "catch-type", "rethrow");
break;
case EX_EVENT_CATCH:
ui_out_field_string (uiout, "what", "exception catch");
if (ui_out_is_mi_like_p (uiout))
ui_out_field_string (uiout, "catch-type", "catch");
break;
}
}
/* Implement the 'print_one_detail' method. */
static void
print_one_detail_exception_catchpoint (const struct breakpoint *b,
struct ui_out *uiout)
{
const struct exception_catchpoint *cp
= (const struct exception_catchpoint *) b;
if (cp->exception_rx != NULL)
{
ui_out_text (uiout, _("\tmatching: "));
ui_out_field_string (uiout, "regexp", cp->exception_rx);
ui_out_text (uiout, "\n");
}
}
static void
print_mention_exception_catchpoint (struct breakpoint *b)
{
struct ui_out *uiout = current_uiout;
int bp_temp;
enum exception_event_kind kind = classify_exception_breakpoint (b);
bp_temp = b->disposition == disp_del;
ui_out_text (uiout, bp_temp ? _("Temporary catchpoint ")
: _("Catchpoint "));
ui_out_field_int (uiout, "bkptno", b->number);
ui_out_text (uiout, (kind == EX_EVENT_THROW ? _(" (throw)")
: (kind == EX_EVENT_CATCH ? _(" (catch)")
: _(" (rethrow)"))));
}
/* Implement the "print_recreate" breakpoint_ops method for throw and
catch catchpoints. */
static void
print_recreate_exception_catchpoint (struct breakpoint *b,
struct ui_file *fp)
{
int bp_temp;
enum exception_event_kind kind = classify_exception_breakpoint (b);
bp_temp = b->disposition == disp_del;
fprintf_unfiltered (fp, bp_temp ? "tcatch " : "catch ");
switch (kind)
{
case EX_EVENT_THROW:
fprintf_unfiltered (fp, "throw");
break;
case EX_EVENT_CATCH:
fprintf_unfiltered (fp, "catch");
break;
case EX_EVENT_RETHROW:
fprintf_unfiltered (fp, "rethrow");
break;
}
print_recreate_thread (b, fp);
}
static void
handle_gnu_v3_exceptions (int tempflag, char *except_rx, char *cond_string,
enum exception_event_kind ex_event, int from_tty)
{
struct exception_catchpoint *cp;
struct cleanup *cleanup = make_cleanup (null_cleanup, NULL);
regex_t *pattern = NULL;
if (except_rx != NULL)
{
pattern = XNEW (regex_t);
make_cleanup (xfree, pattern);
compile_rx_or_error (pattern, except_rx,
_("invalid type-matching regexp"));
}
cp = XCNEW (struct exception_catchpoint);
make_cleanup (xfree, cp);
init_catchpoint (&cp->base, 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->base.type = bp_breakpoint;
cp->kind = ex_event;
cp->exception_rx = except_rx;
cp->pattern = pattern;
re_set_exception_catchpoint (&cp->base);
install_breakpoint (0, &cp->base, 1);
discard_cleanups (cleanup);
}
/* Look for an "if" token in *STRING. The "if" token must be preceded
by whitespace.
If there is any non-whitespace text between *STRING and the "if"
token, then it is returned in a newly-xmalloc'd string. Otherwise,
this returns NULL.
STRING is updated to point to the "if" token, if it exists, or to
the end of the string. */
static char *
extract_exception_regexp (char **string)
{
char *start;
char *last, *last_space;
start = skip_spaces (*string);
last = start;
last_space = start;
while (*last != '\0')
{
char *if_token = last;
/* Check for the "if". */
if (check_for_argument (&if_token, "if", 2))
break;
/* No "if" token here. Skip to the next word start. */
last_space = skip_to_space (last);
last = skip_spaces (last_space);
}
*string = last;
if (last_space > start)
return savestring (start, last_space - start);
return NULL;
}
/* Deal with "catch catch", "catch throw", and "catch rethrow"
commands. */
static void
catch_exception_command_1 (enum exception_event_kind ex_event, char *arg,
int tempflag, int from_tty)
{
char *except_rx;
char *cond_string = NULL;
struct cleanup *cleanup;
if (!arg)
arg = "";
arg = skip_spaces (arg);
except_rx = extract_exception_regexp (&arg);
cleanup = make_cleanup (xfree, except_rx);
cond_string = ep_parse_optional_if_clause (&arg);
if ((*arg != '\0') && !isspace (*arg))
error (_("Junk at end of arguments."));
if (ex_event != EX_EVENT_THROW
&& ex_event != EX_EVENT_CATCH
&& ex_event != EX_EVENT_RETHROW)
error (_("Unsupported or unknown exception event; cannot catch it"));
handle_gnu_v3_exceptions (tempflag, except_rx, cond_string,
ex_event, from_tty);
discard_cleanups (cleanup);
}
/* Implementation of "catch catch" command. */
static void
catch_catch_command (char *arg, int from_tty, struct cmd_list_element *command)
{
int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
catch_exception_command_1 (EX_EVENT_CATCH, arg, tempflag, from_tty);
}
/* Implementation of "catch throw" command. */
static void
catch_throw_command (char *arg, int from_tty, struct cmd_list_element *command)
{
int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
catch_exception_command_1 (EX_EVENT_THROW, arg, tempflag, from_tty);
}
/* Implementation of "catch rethrow" command. */
static void
catch_rethrow_command (char *arg, int from_tty,
struct cmd_list_element *command)
{
int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
catch_exception_command_1 (EX_EVENT_RETHROW, arg, tempflag, from_tty);
}
/* Implement the 'make_value' method for the $_exception
internalvar. */
static struct value *
compute_exception (struct gdbarch *argc, struct internalvar *var, void *ignore)
{
struct value *arg0, *arg1;
struct type *obj_type;
fetch_probe_arguments (&arg0, &arg1);
/* ARG0 is a pointer to the exception object. ARG1 is a pointer to
the std::type_info for the exception. Now we find the type from
the type_info and cast the result. */
obj_type = cplus_type_from_type_info (arg1);
return value_ind (value_cast (make_pointer_type (obj_type, NULL), arg0));
}
/* Implementation of the '$_exception' variable. */
static const struct internalvar_funcs exception_funcs =
{
compute_exception,
NULL,
NULL
};
static void
initialize_throw_catchpoint_ops (void)
{
struct breakpoint_ops *ops;
initialize_breakpoint_ops ();
/* GNU v3 exception catchpoints. */
ops = &gnu_v3_exception_catchpoint_ops;
*ops = bkpt_breakpoint_ops;
ops->dtor = dtor_exception_catchpoint;
ops->re_set = re_set_exception_catchpoint;
ops->print_it = print_it_exception_catchpoint;
ops->print_one = print_one_exception_catchpoint;
ops->print_mention = print_mention_exception_catchpoint;
ops->print_recreate = print_recreate_exception_catchpoint;
ops->print_one_detail = print_one_detail_exception_catchpoint;
ops->check_status = check_status_exception_catchpoint;
}
initialize_file_ftype _initialize_break_catch_throw;
void
_initialize_break_catch_throw (void)
{
initialize_throw_catchpoint_ops ();
/* Add catch and tcatch sub-commands. */
add_catch_command ("catch", _("\
Catch an exception, when caught."),
catch_catch_command,
NULL,
CATCH_PERMANENT,
CATCH_TEMPORARY);
add_catch_command ("throw", _("\
Catch an exception, when thrown."),
catch_throw_command,
NULL,
CATCH_PERMANENT,
CATCH_TEMPORARY);
add_catch_command ("rethrow", _("\
Catch an exception, when rethrown."),
catch_rethrow_command,
NULL,
CATCH_PERMANENT,
CATCH_TEMPORARY);
create_internalvar_type_lazy ("_exception", &exception_funcs, NULL);
}