btrace: pretend we're not replaying when generating a core file

When generating a core file using the "generate-core-file" command while
replaying with the btrace record target, we won't be able to access all
registers and all memory.  This leads to the following assertion:

    gdb/regcache.c:1034: internal-error: regcache_raw_supply: Assertion `regnum >= 0 && regnum < regcache->descr->nr_raw_registers' failed.
    A problem internal to GDB has been detected,
    further debugging may prove unreliable.
    Quit this debugging session? (y or n) FAIL: gdb.btrace/gcore.exp: generate-core-file core (GDB internal error)
    Resyncing due to internal error.

Pretend that we are not replaying while generating a core file.  This will
forward fetch and store registers as well as xfer memory calls to the target
beneath.

gdb/
	* record-btrace.c (record_btrace_generating_corefile)
	(record_btrace_prepare_to_generate_core)
	(record_btrace_done_generating_core): New.
	(record_btrace_xfer_partial, record_btrace_fetch_registers)
	(record_btrace_store_registers, record_btrace_prepare_to_store):
	Forward request when generating a core file.
	(record_btrace_open): Set record_btrace_generating_corefile to zero.
	(init_record_btrace_ops): Set to_prepare_to_generate_core and
	to_done_generating_core.

testsuite/
	* gdb.btrace/gcore.exp: New.
This commit is contained in:
Markus Metzger 2014-05-20 15:53:44 +02:00
parent 5fff78c4e0
commit aef929023e
4 changed files with 83 additions and 3 deletions

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@ -1,3 +1,15 @@
2014-06-25 Markus Metzger <markus.t.metzger@intel.com>
* record-btrace.c (record_btrace_generating_corefile)
(record_btrace_prepare_to_generate_core)
(record_btrace_done_generating_core): New.
(record_btrace_xfer_partial, record_btrace_fetch_registers)
(record_btrace_store_registers, record_btrace_prepare_to_store):
Forward request when generating a core file.
(record_btrace_open): Set record_btrace_generating_corefile to zero.
(init_record_btrace_ops): Set to_prepare_to_generate_core and
to_done_generating_core.
2014-06-25 Markus Metzger <markus.t.metzger@intel.com>
* target.h (target_ops) <to_prepare_to_generate_core>

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@ -68,6 +68,9 @@ static enum exec_direction_kind record_btrace_resume_exec_dir = EXEC_FORWARD;
/* The async event handler for reverse/replay execution. */
static struct async_event_handler *record_btrace_async_inferior_event_handler;
/* A flag indicating that we are currently generating a core file. */
static int record_btrace_generating_corefile;
/* Print a record-btrace debug message. Use do ... while (0) to avoid
ambiguities when used in if statements. */
@ -221,6 +224,7 @@ record_btrace_open (char *args, int from_tty)
record_btrace_async_inferior_event_handler
= create_async_event_handler (record_btrace_handle_async_inferior_event,
NULL);
record_btrace_generating_corefile = 0;
observer_notify_record_changed (current_inferior (), 1);
@ -854,6 +858,7 @@ record_btrace_xfer_partial (struct target_ops *ops, enum target_object object,
/* Filter out requests that don't make sense during replay. */
if (replay_memory_access == replay_memory_access_read_only
&& !record_btrace_generating_corefile
&& record_btrace_is_replaying (ops))
{
switch (object)
@ -969,7 +974,7 @@ record_btrace_fetch_registers (struct target_ops *ops,
gdb_assert (tp != NULL);
replay = tp->btrace.replay;
if (replay != NULL)
if (replay != NULL && !record_btrace_generating_corefile)
{
const struct btrace_insn *insn;
struct gdbarch *gdbarch;
@ -1010,7 +1015,7 @@ record_btrace_store_registers (struct target_ops *ops,
{
struct target_ops *t;
if (record_btrace_is_replaying (ops))
if (!record_btrace_generating_corefile && record_btrace_is_replaying (ops))
error (_("This record target does not allow writing registers."));
gdb_assert (may_write_registers != 0);
@ -1033,7 +1038,7 @@ record_btrace_prepare_to_store (struct target_ops *ops,
{
struct target_ops *t;
if (record_btrace_is_replaying (ops))
if (!record_btrace_generating_corefile && record_btrace_is_replaying (ops))
return;
for (t = ops->beneath; t != NULL; t = t->beneath)
@ -1939,6 +1944,22 @@ record_btrace_execution_direction (struct target_ops *self)
return record_btrace_resume_exec_dir;
}
/* The to_prepare_to_generate_core target method. */
static void
record_btrace_prepare_to_generate_core (struct target_ops *self)
{
record_btrace_generating_corefile = 1;
}
/* The to_done_generating_core target method. */
static void
record_btrace_done_generating_core (struct target_ops *self)
{
record_btrace_generating_corefile = 0;
}
/* Initialize the record-btrace target ops. */
static void
@ -1983,6 +2004,8 @@ init_record_btrace_ops (void)
ops->to_can_execute_reverse = record_btrace_can_execute_reverse;
ops->to_decr_pc_after_break = record_btrace_decr_pc_after_break;
ops->to_execution_direction = record_btrace_execution_direction;
ops->to_prepare_to_generate_core = record_btrace_prepare_to_generate_core;
ops->to_done_generating_core = record_btrace_done_generating_core;
ops->to_stratum = record_stratum;
ops->to_magic = OPS_MAGIC;
}

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@ -1,3 +1,7 @@
2014-06-25 Markus Metzger <markus.t.metzger@intel.com>
* gdb.btrace/gcore.exp: New.
2014-06-23 Pedro Alves <palves@redhat.com>
* gdb.base/watchpoint-reuse-slot.c: New file.

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@ -0,0 +1,41 @@
# This testcase is part of GDB, the GNU debugger.
#
# Copyright 2014 Free Software Foundation, Inc.
#
# Contributed by Intel Corp. <markus.t.metzger@intel.com>
#
# 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/>.
# check for btrace support
if { [skip_btrace_tests] } { return -1 }
# start inferior
standard_testfile x86-record_goto.S
if [prepare_for_testing gcore.exp $testfile $srcfile] {
return -1
}
if ![runto_main] {
return -1
}
# trace the call to the test function
gdb_test_no_output "record btrace"
gdb_test "next" ".*main\.3.*"
# start replaying
gdb_test "record goto begin" ".*main\.2.*"
# generate a core file - this used to assert
gdb_test "generate-core-file core" "Saved corefile core"