binutils-gdb/gdb/mi/mi-cmd-stack.c
Joel Brobecker f7e44f6574 GDB/MI: crash printing "_task" (Ada) argument
In GDB/MI mode, trying to print the arguments of the frame corresponding
to the body of a task ("-stack-list-arguments 1") causes the debugger to
crash.

This is because the compiler adds an implicit argument to that task body
called "_task". mi/mi-cmd-stack.c:list_args_or_locals, which is
responsible for printing the value of our arguments, finds that our
"_task" symbol is an argument, and thus tries to fing the non-argument
equivalent:

              if (SYMBOL_IS_ARGUMENT (sym))
                sym2 = lookup_symbol (SYMBOL_NATURAL_NAME (sym),
                                      block, VAR_DOMAIN,
                                      (int *) NULL);

Unfortunately, it tries using the natural name, which doesn't always
work for Ada parameters, in particular those who are internally-
generated. In our case, The "_task" parameter's natural name is
"<_task>", and that symbol does not exist.  So sym2 is NULL, thus
causing the crash a little later on when trying to dereference it.
We should be using the symbol linkage name in this case, the same
way iterate_over_block_arg_vars already does.

gdb/ChangeLog:

        * mi/mi-cmd-stack.c (list_args_or_locals): For argument symbols,
        use SYMBOL_LINKAGE_NAME to find the corresponding non-argument
        symbol.  Add assertion that sym2 is never NULL.

gdb/testsuite/ChangeLog:

        * gdb.ada/mi_task_arg: New testcase.
2012-02-03 07:32:40 +00:00

454 lines
13 KiB
C

/* MI Command Set - stack commands.
Copyright (C) 2000, 2002-2005, 2007-2012 Free Software Foundation,
Inc.
Contributed by Cygnus Solutions (a Red Hat company).
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 "target.h"
#include "frame.h"
#include "value.h"
#include "mi-cmds.h"
#include "ui-out.h"
#include "symtab.h"
#include "block.h"
#include "stack.h"
#include "dictionary.h"
#include "gdb_string.h"
#include "language.h"
#include "valprint.h"
#include "exceptions.h"
enum what_to_list { locals, arguments, all };
static void list_args_or_locals (enum what_to_list what,
enum print_values values,
struct frame_info *fi);
/* Print a list of the stack frames. Args can be none, in which case
we want to print the whole backtrace, or a pair of numbers
specifying the frame numbers at which to start and stop the
display. If the two numbers are equal, a single frame will be
displayed. */
void
mi_cmd_stack_list_frames (char *command, char **argv, int argc)
{
int frame_low;
int frame_high;
int i;
struct cleanup *cleanup_stack;
struct frame_info *fi;
if (argc > 2 || argc == 1)
error (_("-stack-list-frames: Usage: [FRAME_LOW FRAME_HIGH]"));
if (argc == 2)
{
frame_low = atoi (argv[0]);
frame_high = atoi (argv[1]);
}
else
{
/* Called with no arguments, it means we want the whole
backtrace. */
frame_low = -1;
frame_high = -1;
}
/* Let's position fi on the frame at which to start the
display. Could be the innermost frame if the whole stack needs
displaying, or if frame_low is 0. */
for (i = 0, fi = get_current_frame ();
fi && i < frame_low;
i++, fi = get_prev_frame (fi));
if (fi == NULL)
error (_("-stack-list-frames: Not enough frames in stack."));
cleanup_stack = make_cleanup_ui_out_list_begin_end (current_uiout, "stack");
/* Now let;s print the frames up to frame_high, or until there are
frames in the stack. */
for (;
fi && (i <= frame_high || frame_high == -1);
i++, fi = get_prev_frame (fi))
{
QUIT;
/* Print the location and the address always, even for level 0.
args == 0: don't print the arguments. */
print_frame_info (fi, 1, LOC_AND_ADDRESS, 0 /* args */ );
}
do_cleanups (cleanup_stack);
}
void
mi_cmd_stack_info_depth (char *command, char **argv, int argc)
{
int frame_high;
int i;
struct frame_info *fi;
if (argc > 1)
error (_("-stack-info-depth: Usage: [MAX_DEPTH]"));
if (argc == 1)
frame_high = atoi (argv[0]);
else
/* Called with no arguments, it means we want the real depth of
the stack. */
frame_high = -1;
for (i = 0, fi = get_current_frame ();
fi && (i < frame_high || frame_high == -1);
i++, fi = get_prev_frame (fi))
QUIT;
ui_out_field_int (current_uiout, "depth", i);
}
static enum print_values
parse_print_values (char *name)
{
if (strcmp (name, "0") == 0
|| strcmp (name, mi_no_values) == 0)
return PRINT_NO_VALUES;
else if (strcmp (name, "1") == 0
|| strcmp (name, mi_all_values) == 0)
return PRINT_ALL_VALUES;
else if (strcmp (name, "2") == 0
|| strcmp (name, mi_simple_values) == 0)
return PRINT_SIMPLE_VALUES;
else
error (_("Unknown value for PRINT_VALUES: must be: \
0 or \"%s\", 1 or \"%s\", 2 or \"%s\""),
mi_no_values, mi_all_values, mi_simple_values);
}
/* Print a list of the locals for the current frame. With argument of
0, print only the names, with argument of 1 print also the
values. */
void
mi_cmd_stack_list_locals (char *command, char **argv, int argc)
{
struct frame_info *frame;
if (argc != 1)
error (_("-stack-list-locals: Usage: PRINT_VALUES"));
frame = get_selected_frame (NULL);
list_args_or_locals (locals, parse_print_values (argv[0]), frame);
}
/* Print a list of the arguments for the current frame. With argument
of 0, print only the names, with argument of 1 print also the
values. */
void
mi_cmd_stack_list_args (char *command, char **argv, int argc)
{
int frame_low;
int frame_high;
int i;
struct frame_info *fi;
struct cleanup *cleanup_stack_args;
enum print_values print_values;
struct ui_out *uiout = current_uiout;
if (argc < 1 || argc > 3 || argc == 2)
error (_("-stack-list-arguments: Usage: "
"PRINT_VALUES [FRAME_LOW FRAME_HIGH]"));
if (argc == 3)
{
frame_low = atoi (argv[1]);
frame_high = atoi (argv[2]);
}
else
{
/* Called with no arguments, it means we want args for the whole
backtrace. */
frame_low = -1;
frame_high = -1;
}
print_values = parse_print_values (argv[0]);
/* Let's position fi on the frame at which to start the
display. Could be the innermost frame if the whole stack needs
displaying, or if frame_low is 0. */
for (i = 0, fi = get_current_frame ();
fi && i < frame_low;
i++, fi = get_prev_frame (fi));
if (fi == NULL)
error (_("-stack-list-arguments: Not enough frames in stack."));
cleanup_stack_args
= make_cleanup_ui_out_list_begin_end (uiout, "stack-args");
/* Now let's print the frames up to frame_high, or until there are
frames in the stack. */
for (;
fi && (i <= frame_high || frame_high == -1);
i++, fi = get_prev_frame (fi))
{
struct cleanup *cleanup_frame;
QUIT;
cleanup_frame = make_cleanup_ui_out_tuple_begin_end (uiout, "frame");
ui_out_field_int (uiout, "level", i);
list_args_or_locals (arguments, print_values, fi);
do_cleanups (cleanup_frame);
}
do_cleanups (cleanup_stack_args);
}
/* Print a list of the local variables (including arguments) for the
current frame. ARGC must be 1 and ARGV[0] specify if only the names,
or both names and values of the variables must be printed. See
parse_print_value for possible values. */
void
mi_cmd_stack_list_variables (char *command, char **argv, int argc)
{
struct frame_info *frame;
if (argc != 1)
error (_("Usage: PRINT_VALUES"));
frame = get_selected_frame (NULL);
list_args_or_locals (all, parse_print_values (argv[0]), frame);
}
/* Print single local or argument. ARG must be already read in. For WHAT and
VALUES see list_args_or_locals.
Errors are printed as if they would be the parameter value. Use zeroed ARG
iff it should not be printed accoring to VALUES. */
static void
list_arg_or_local (const struct frame_arg *arg, enum what_to_list what,
enum print_values values)
{
struct cleanup *cleanup_tuple = NULL;
struct ui_out *uiout = current_uiout;
struct ui_stream *stb = ui_out_stream_new (uiout);
gdb_assert (!arg->val || !arg->error);
gdb_assert ((values == PRINT_NO_VALUES && arg->val == NULL
&& arg->error == NULL)
|| values == PRINT_SIMPLE_VALUES
|| (values == PRINT_ALL_VALUES
&& (arg->val != NULL || arg->error != NULL)));
gdb_assert (arg->entry_kind == print_entry_values_no
|| (arg->entry_kind == print_entry_values_only
&& (arg->val || arg->error)));
if (values != PRINT_NO_VALUES || what == all)
cleanup_tuple = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
fputs_filtered (SYMBOL_PRINT_NAME (arg->sym), stb->stream);
if (arg->entry_kind == print_entry_values_only)
fputs_filtered ("@entry", stb->stream);
ui_out_field_stream (uiout, "name", stb);
if (what == all && SYMBOL_IS_ARGUMENT (arg->sym))
ui_out_field_int (uiout, "arg", 1);
if (values == PRINT_SIMPLE_VALUES)
{
check_typedef (arg->sym->type);
type_print (arg->sym->type, "", stb->stream, -1);
ui_out_field_stream (uiout, "type", stb);
}
if (arg->val || arg->error)
{
volatile struct gdb_exception except;
if (arg->error)
except.message = arg->error;
else
{
/* TRY_CATCH has two statements, wrap it in a block. */
TRY_CATCH (except, RETURN_MASK_ERROR)
{
struct value_print_options opts;
get_raw_print_options (&opts);
opts.deref_ref = 1;
common_val_print (arg->val, stb->stream, 0, &opts,
language_def (SYMBOL_LANGUAGE (arg->sym)));
}
}
if (except.message)
fprintf_filtered (stb->stream, _("<error reading variable: %s>"),
except.message);
ui_out_field_stream (uiout, "value", stb);
}
ui_out_stream_delete (stb);
if (values != PRINT_NO_VALUES || what == all)
do_cleanups (cleanup_tuple);
}
/* Print a list of the locals or the arguments for the currently
selected frame. If the argument passed is 0, printonly the names
of the variables, if an argument of 1 is passed, print the values
as well. */
static void
list_args_or_locals (enum what_to_list what, enum print_values values,
struct frame_info *fi)
{
struct block *block;
struct symbol *sym;
struct dict_iterator iter;
struct cleanup *cleanup_list;
struct ui_stream *stb;
struct type *type;
char *name_of_result;
struct ui_out *uiout = current_uiout;
stb = ui_out_stream_new (uiout);
block = get_frame_block (fi, 0);
switch (what)
{
case locals:
name_of_result = "locals";
break;
case arguments:
name_of_result = "args";
break;
case all:
name_of_result = "variables";
break;
default:
internal_error (__FILE__, __LINE__,
"unexpected what_to_list: %d", (int) what);
}
cleanup_list = make_cleanup_ui_out_list_begin_end (uiout, name_of_result);
while (block != 0)
{
ALL_BLOCK_SYMBOLS (block, iter, sym)
{
int print_me = 0;
switch (SYMBOL_CLASS (sym))
{
default:
case LOC_UNDEF: /* catches errors */
case LOC_CONST: /* constant */
case LOC_TYPEDEF: /* local typedef */
case LOC_LABEL: /* local label */
case LOC_BLOCK: /* local function */
case LOC_CONST_BYTES: /* loc. byte seq. */
case LOC_UNRESOLVED: /* unresolved static */
case LOC_OPTIMIZED_OUT: /* optimized out */
print_me = 0;
break;
case LOC_ARG: /* argument */
case LOC_REF_ARG: /* reference arg */
case LOC_REGPARM_ADDR: /* indirect register arg */
case LOC_LOCAL: /* stack local */
case LOC_STATIC: /* static */
case LOC_REGISTER: /* register */
case LOC_COMPUTED: /* computed location */
if (what == all)
print_me = 1;
else if (what == locals)
print_me = !SYMBOL_IS_ARGUMENT (sym);
else
print_me = SYMBOL_IS_ARGUMENT (sym);
break;
}
if (print_me)
{
struct symbol *sym2;
struct frame_arg arg, entryarg;
if (SYMBOL_IS_ARGUMENT (sym))
sym2 = lookup_symbol (SYMBOL_LINKAGE_NAME (sym),
block, VAR_DOMAIN,
(int *) NULL);
else
sym2 = sym;
gdb_assert (sym2 != NULL);
memset (&arg, 0, sizeof (arg));
arg.sym = sym2;
arg.entry_kind = print_entry_values_no;
memset (&entryarg, 0, sizeof (entryarg));
entryarg.sym = sym2;
entryarg.entry_kind = print_entry_values_no;
switch (values)
{
case PRINT_SIMPLE_VALUES:
type = check_typedef (sym2->type);
if (TYPE_CODE (type) != TYPE_CODE_ARRAY
&& TYPE_CODE (type) != TYPE_CODE_STRUCT
&& TYPE_CODE (type) != TYPE_CODE_UNION)
{
case PRINT_ALL_VALUES:
read_frame_arg (sym2, fi, &arg, &entryarg);
}
break;
}
if (arg.entry_kind != print_entry_values_only)
list_arg_or_local (&arg, what, values);
if (entryarg.entry_kind != print_entry_values_no)
list_arg_or_local (&entryarg, what, values);
xfree (arg.error);
xfree (entryarg.error);
}
}
if (BLOCK_FUNCTION (block))
break;
else
block = BLOCK_SUPERBLOCK (block);
}
do_cleanups (cleanup_list);
ui_out_stream_delete (stb);
}
void
mi_cmd_stack_select_frame (char *command, char **argv, int argc)
{
if (argc == 0 || argc > 1)
error (_("-stack-select-frame: Usage: FRAME_SPEC"));
select_frame_command (argv[0], 1 /* not used */ );
}
void
mi_cmd_stack_info_frame (char *command, char **argv, int argc)
{
if (argc > 0)
error (_("-stack-info-frame: No arguments required"));
print_frame_info (get_selected_frame (NULL), 1, LOC_AND_ADDRESS, 0);
}