binutils-gdb/gdbsupport/common-regcache.h
Tankut Baris Aktemur fc75c28ba1 gdb: protect some 'regcache_read_pc' calls
It possible that a thread whose PC we attempt to read is already dead.
In this case, 'regcache_read_pc' errors out.  This impacts the
"proceed" execution flow, where GDB quits early before having a chance
to check if there exists a pending event.  To remedy, keep going with
a 0 value for the PC if 'regcache_read_pc' fails.  Because the value
of PC before resuming a thread is mostly used for storing and checking
the next time the thread stops, this tolerance is expected to be
harmless for a dead thread/process.

gdb/ChangeLog:
2020-05-14  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* regcache.c (regcache_read_pc_protected): New function
	implementation that returns 0 if the PC cannot read via
	'regcache_read_pc'.
	* infrun.c (proceed): Call 'regcache_read_pc_protected'
	instead of 'regcache_read_pc'.
	(keep_going_pass_signal): Ditto.

gdbsupport/ChangeLog:
2020-05-14  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* common-regcache.h (regcache_read_pc_protected): New function
	declaration.
2020-05-14 13:59:53 +02:00

91 lines
3.3 KiB
C

/* Cache and manage the values of registers
Copyright (C) 2014-2020 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 COMMON_COMMON_REGCACHE_H
#define COMMON_COMMON_REGCACHE_H
/* This header is a stopgap until we have an independent regcache. */
enum register_status : signed char
{
/* The register value is not in the cache, and we don't know yet
whether it's available in the target (or traceframe). */
REG_UNKNOWN = 0,
/* The register value is valid and cached. */
REG_VALID = 1,
/* The register value is unavailable. E.g., we're inspecting a
traceframe, and this register wasn't collected. Note that this
is different a different "unavailable" from saying the register
does not exist in the target's architecture --- in that case,
the target should have given us a target description that does
not include the register in the first place. */
REG_UNAVAILABLE = -1
};
/* Return a pointer to the register cache associated with the
thread specified by PTID. This function must be provided by
the client. */
extern struct regcache *get_thread_regcache_for_ptid (ptid_t ptid);
/* Return the size of register numbered N in REGCACHE. This function
must be provided by the client. */
extern int regcache_register_size (const struct regcache *regcache, int n);
/* Read the PC register. This function must be provided by the
client. */
extern CORE_ADDR regcache_read_pc (struct regcache *regcache);
/* Read the PC register. If PC cannot be read, return 0.
This is a wrapper around 'regcache_read_pc'. */
extern CORE_ADDR regcache_read_pc_protected (regcache *regcache);
/* Read a raw register into a unsigned integer. */
extern enum register_status regcache_raw_read_unsigned
(struct regcache *regcache, int regnum, ULONGEST *val);
ULONGEST regcache_raw_get_unsigned (struct regcache *regcache, int regnum);
struct reg_buffer_common
{
virtual ~reg_buffer_common () = default;
/* Get the availability status of the value of register REGNUM in this
buffer. */
virtual register_status get_register_status (int regnum) const = 0;
/* Supply register REGNUM, whose contents are stored in BUF, to REGCACHE. */
virtual void raw_supply (int regnum, const void *buf) = 0;
/* Collect register REGNUM from REGCACHE and store its contents in BUF. */
virtual void raw_collect (int regnum, void *buf) const = 0;
/* Compare the contents of the register stored in the regcache (ignoring the
first OFFSET bytes) to the contents of BUF (without any offset). Returns
true if the same. */
virtual bool raw_compare (int regnum, const void *buf, int offset) const = 0;
};
#endif /* COMMON_COMMON_REGCACHE_H */