binutils-gdb/gdb/location.h
Joel Brobecker 305e13e67f Fix regression introduced in "break *<EXPR>" by explicit location patches.
A relatively recent patch support for explicit locations, and part
of that patch cleaned up the way we parse breakpoint locations.
Unfortunatly, a small regression crept in for "*<EXPR>" breakpoint
locations. In particular, on PIE programs, one can see the issue by
doing the following, with any program:

    (gdb) b *main
    Breakpoint 1 at 0x51a: file hello.c, line 3.
    (gdb) run
    Starting program: /[...]/hello
    Error in re-setting breakpoint 1: Warning:
    Cannot insert breakpoint 1.
    Cannot access memory at address 0x51a

    Warning:
    Cannot insert breakpoint 1.
    Cannot access memory at address 0x51a

Just for the record, this regression was introduced by:

    commit a06efdd6ef
    Date:   Tue Aug 11 17:09:35 2015 -0700
    Subject: Explicit locations: introduce address locations

What happens is that the patch makes the implicit assumption that
the address computed the first time is static, as if it was designed
to only support litteral expressions (Eg. "*0x1234"). This allows
the shortcut of not re-computing the breakpoint location's address
when re-setting breakpoints.

However, this does not work in general, as demonstrated in the example
above.

This patch plugs that hole simply by saving the original expression
used to compute the address as part of the address location, so as
to then re-evaluate that expression during breakpoint re-set.

gdb/ChangeLog:

        * location.h (new_address_location): Add new parameters
        "addr_string" and "addr_string_len".
        (get_address_string_location): Add declaration.
        * location.c (new_address_location): Add new parameters
        "addr_string" and "addr_string_len".  If not NULL, store
        a copy of the addr_string in the new location as well.
        (get_address_string_location): New function.
        (string_to_event_location): Update call to new_address_location.
        * linespec.c (event_location_to_sals) <ADDRESS_LOCATION>:
        Save the event location in the parser's state before
        passing it to convert_address_location_to_sals.
        * breakpoint.c (create_thread_event_breakpoint): Update call
        to new_address_location.
        (init_breakpoint_sal): Get the event location's string, if any,
        and use it to update call to new_address_location.
        * python/py-finishbreakpoint.c (bpfinishpy_init):
        Update call to new_address_location.
        * spu-tdep.c (spu_catch_start): Likewise.

        * config/djgpp/fnchange.lst: Add entries for
        gdb/testsuite/gdb.base/break-fun-addr1.c and
        gdb/testsuite/gdb.base/break-fun-addr2.c.

gdb/testsuite/ChangeLog:

        * gdb.base/break-fun-addr.exp: New file.
        * gdb.base/break-fun-addr1.c: New file.
        * gdb.base/break-fun-addr2.c: New file.
2016-01-21 14:23:15 +04:00

242 lines
7.5 KiB
C

/* Data structures and API for event locations in GDB.
Copyright (C) 2013-2016 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/>. */
#ifndef LOCATIONS_H
#define LOCATIONS_H 1
struct language_defn;
struct event_location;
/* An enumeration of possible signs for a line offset. */
enum offset_relative_sign
{
/* No sign */
LINE_OFFSET_NONE,
/* A plus sign ("+") */
LINE_OFFSET_PLUS,
/* A minus sign ("-") */
LINE_OFFSET_MINUS,
/* A special "sign" for unspecified offset. */
LINE_OFFSET_UNKNOWN
};
/* A line offset in a location. */
struct line_offset
{
/* Line offset and any specified sign. */
int offset;
enum offset_relative_sign sign;
};
/* An enumeration of the various ways to specify a stop event
location (used with create_breakpoint). */
enum event_location_type
{
/* A traditional linespec. */
LINESPEC_LOCATION,
/* An address in the inferior. */
ADDRESS_LOCATION,
/* An explicit location. */
EXPLICIT_LOCATION,
/* A probe location. */
PROBE_LOCATION
};
/* An explicit location. This structure is used to bypass the
parsing done on linespecs. It still has the same requirements
as linespecs, though. For example, source_filename requires
at least one other field. */
struct explicit_location
{
/* The source filename. Malloc'd. */
char *source_filename;
/* The function name. Malloc'd. */
char *function_name;
/* The name of a label. Malloc'd. */
char *label_name;
/* A line offset relative to the start of the symbol
identified by the above fields or the current symtab
if the other fields are NULL. */
struct line_offset line_offset;
};
/* Return the type of the given event location. */
extern enum event_location_type
event_location_type (const struct event_location *);
/* Return a malloc'd explicit string representation of the given
explicit location. The location must already be canonicalized/valid. */
extern char *
explicit_location_to_string (const struct explicit_location *explicit_loc);
/* Return a malloc'd linespec string representation of the given
explicit location. The location must already be canonicalized/valid. */
extern char *
explicit_location_to_linespec (const struct explicit_location *explicit_loc);
/* Return a string representation of the LOCATION.
This function may return NULL for unspecified linespecs,
e.g, LOCATION_LINESPEC and addr_string is NULL.
The result is cached in LOCATION. */
extern const char *
event_location_to_string (struct event_location *location);
/* Create a new linespec location. The return result is malloc'd
and should be freed with delete_event_location. */
extern struct event_location *
new_linespec_location (char **linespec);
/* Return the linespec location (a string) of the given event_location
(which must be of type LINESPEC_LOCATION). */
extern const char *
get_linespec_location (const struct event_location *location);
/* Create a new address location.
ADDR is the address corresponding to this event_location.
ADDR_STRING, a string of ADDR_STRING_LEN characters, is
the expression that was parsed to determine the address ADDR. */
extern struct event_location *
new_address_location (CORE_ADDR addr, const char *addr_string,
int addr_string_len);
/* Return the address location (a CORE_ADDR) of the given event_location
(which must be of type ADDRESS_LOCATION). */
extern CORE_ADDR
get_address_location (const struct event_location *location);
/* Return the expression (a string) that was used to compute the address
of the given event_location (which must be of type ADDRESS_LOCATION). */
extern const char *
get_address_string_location (const struct event_location *location);
/* Create a new probe location. The return result is malloc'd
and should be freed with delete_event_location. */
extern struct event_location *
new_probe_location (const char *probe);
/* Return the probe location (a string) of the given event_location
(which must be of type PROBE_LOCATION). */
extern const char *
get_probe_location (const struct event_location *location);
/* Initialize the given explicit location. */
extern void
initialize_explicit_location (struct explicit_location *explicit_loc);
/* Create a new explicit location. If not NULL, EXPLICIT is checked for
validity. If invalid, an exception is thrown.
The return result is malloc'd and should be freed with
delete_event_location. */
extern struct event_location *
new_explicit_location (const struct explicit_location *explicit_loc);
/* Return the explicit location of the given event_location
(which must be of type EXPLICIT_LOCATION). */
extern struct explicit_location *
get_explicit_location (struct event_location *location);
/* A const version of the above. */
extern const struct explicit_location *
get_explicit_location_const (const struct event_location *location);
/* Free an event location and any associated data. */
extern void delete_event_location (struct event_location *location);
/* Make a cleanup to free LOCATION. */
extern struct cleanup *
make_cleanup_delete_event_location (struct event_location *location);
/* Return a copy of the given SRC location. */
extern struct event_location *
copy_event_location (const struct event_location *src);
/* Attempt to convert the input string in *ARGP into an event_location.
ARGP is advanced past any processed input. Returns an event_location
(malloc'd) if an event location was successfully found in *ARGP,
NULL otherwise.
This function may call error() if *ARGP looks like properly formed,
but invalid, input, e.g., if it is called with missing argument parameters
or invalid options.
The return result must be freed with delete_event_location. */
extern struct event_location *
string_to_event_location (char **argp,
const struct language_defn *langauge);
/* Attempt to convert the input string in *ARGP into an explicit location.
ARGP is advanced past any processed input. Returns an event_location
(malloc'd) if an explicit location was successfully found in *ARGP,
NULL otherwise.
IF !DONT_THROW, this function may call error() if *ARGP looks like
properly formed input, e.g., if it is called with missing argument
parameters or invalid options. If DONT_THROW is non-zero, this function
will not throw any exceptions. */
extern struct event_location *
string_to_explicit_location (const char **argp,
const struct language_defn *langauge,
int dont_throw);
/* A convenience function for testing for unset locations. */
extern int event_location_empty_p (const struct event_location *location);
/* Set the location's string representation. If STRING is NULL, clear
the string representation. */
extern void
set_event_location_string (struct event_location *location,
const char *string);
#endif /* LOCATIONS_H */