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-rw-r--r--gdb/ChangeLog12
-rw-r--r--gdb/infrun.c112
-rw-r--r--gdb/testsuite/ChangeLog5
-rw-r--r--gdb/testsuite/gdb.base/valgrind-disp-step.c32
-rw-r--r--gdb/testsuite/gdb.base/valgrind-disp-step.exp136
5 files changed, 277 insertions, 20 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a397960..33cb8fa 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,17 @@
2015-08-07 Pedro Alves <palves@redhat.com>
+ * inferior.h (struct inferior) <displaced_stepping_failed>: New
+ field.
+ * infrun.c (use_displaced_stepping_now_p): New parameter 'inf'.
+ Return false if dispaced stepping failed before.
+ (resume): Pass the current inferior to
+ use_displaced_stepping_now_p. Wrap displaced_step_prepare in
+ TRY/CATCH. If we get a MEMORY_ERROR, set the inferior's
+ displaced_stepping_failed flag, and fall back to an in-line
+ step-over.
+
+2015-08-07 Pedro Alves <palves@redhat.com>
+
* darwin-nat.c (darwin_stop): Rename to ...
(darwin_interrupt): ... this.
(_initialize_darwin_inferior): Adjust.
diff --git a/gdb/infrun.c b/gdb/infrun.c
index f1d8e7c..157c12c 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -1468,6 +1468,10 @@ struct displaced_step_inferior_state
/* The process this displaced step state refers to. */
int pid;
+ /* True if preparing a displaced step ever failed. If so, we won't
+ try displaced stepping for this inferior again. */
+ int failed_before;
+
/* If this is not null_ptid, this is the thread carrying out a
displaced single-step in process PID. This thread's state will
require fixing up once it has completed its step. */
@@ -1638,16 +1642,24 @@ show_can_use_displaced_stepping (struct ui_file *file, int from_tty,
}
/* Return non-zero if displaced stepping can/should be used to step
- over breakpoints. */
+ over breakpoints of thread TP. */
static int
-use_displaced_stepping (struct gdbarch *gdbarch)
+use_displaced_stepping (struct thread_info *tp)
{
+ struct regcache *regcache = get_thread_regcache (tp->ptid);
+ struct gdbarch *gdbarch = get_regcache_arch (regcache);
+ struct displaced_step_inferior_state *displaced_state;
+
+ displaced_state = get_displaced_stepping_state (ptid_get_pid (tp->ptid));
+
return (((can_use_displaced_stepping == AUTO_BOOLEAN_AUTO
&& target_is_non_stop_p ())
|| can_use_displaced_stepping == AUTO_BOOLEAN_TRUE)
&& gdbarch_displaced_step_copy_insn_p (gdbarch)
- && find_record_target () == NULL);
+ && find_record_target () == NULL
+ && (displaced_state == NULL
+ || !displaced_state->failed_before));
}
/* Clean out any stray displaced stepping state. */
@@ -1701,7 +1713,7 @@ displaced_step_dump_bytes (struct ui_file *file,
Returns 1 if preparing was successful -- this thread is going to be
stepped now; or 0 if displaced stepping this thread got queued. */
static int
-displaced_step_prepare (ptid_t ptid)
+displaced_step_prepare_throw (ptid_t ptid)
{
struct cleanup *old_cleanups, *ignore_cleanups;
struct thread_info *tp = find_thread_ptid (ptid);
@@ -1811,6 +1823,50 @@ displaced_step_prepare (ptid_t ptid)
return 1;
}
+/* Wrapper for displaced_step_prepare_throw that disabled further
+ attempts at displaced stepping if we get a memory error. */
+
+static int
+displaced_step_prepare (ptid_t ptid)
+{
+ int prepared = -1;
+
+ TRY
+ {
+ prepared = displaced_step_prepare_throw (ptid);
+ }
+ CATCH (ex, RETURN_MASK_ERROR)
+ {
+ struct displaced_step_inferior_state *displaced_state;
+
+ if (ex.error != MEMORY_ERROR)
+ throw_exception (ex);
+
+ if (debug_infrun)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "infrun: disabling displaced stepping: %s\n",
+ ex.message);
+ }
+
+ /* Be verbose if "set displaced-stepping" is "on", silent if
+ "auto". */
+ if (can_use_displaced_stepping == AUTO_BOOLEAN_TRUE)
+ {
+ warning (_("disabling displaced stepping: %s\n"),
+ ex.message);
+ }
+
+ /* Disable further displaced stepping attempts. */
+ displaced_state
+ = get_displaced_stepping_state (ptid_get_pid (ptid));
+ displaced_state->failed_before = 1;
+ }
+ END_CATCH
+
+ return prepared;
+}
+
static void
write_memory_ptid (ptid_t ptid, CORE_ADDR memaddr,
const gdb_byte *myaddr, int len)
@@ -1941,6 +1997,7 @@ static void keep_going_pass_signal (struct execution_control_state *ecs);
static void prepare_to_wait (struct execution_control_state *ecs);
static int keep_going_stepped_thread (struct thread_info *tp);
static int thread_still_needs_step_over (struct thread_info *tp);
+static void stop_all_threads (void);
/* Are there any pending step-over requests? If so, run all we can
now and return true. Otherwise, return false. */
@@ -1961,8 +2018,6 @@ start_step_over (void)
struct execution_control_state *ecs = &ecss;
enum step_over_what step_what;
int must_be_in_line;
- struct regcache *regcache = get_thread_regcache (tp->ptid);
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
next = thread_step_over_chain_next (tp);
@@ -1974,7 +2029,7 @@ start_step_over (void)
step_what = thread_still_needs_step_over (tp);
must_be_in_line = ((step_what & STEP_OVER_WATCHPOINT)
|| ((step_what & STEP_OVER_BREAKPOINT)
- && !use_displaced_stepping (gdbarch)));
+ && !use_displaced_stepping (tp)));
/* We currently stop all threads of all processes to step-over
in-line. If we need to start a new in-line step-over, let
@@ -2434,15 +2489,15 @@ resume (enum gdb_signal sig)
We can't use displaced stepping when we are waiting for vfork_done
event, displaced stepping breaks the vfork child similarly as single
step software breakpoint. */
- if (use_displaced_stepping (gdbarch)
- && tp->control.trap_expected
+ if (tp->control.trap_expected
+ && use_displaced_stepping (tp)
&& !step_over_info_valid_p ()
&& sig == GDB_SIGNAL_0
&& !current_inferior ()->waiting_for_vfork_done)
{
- struct displaced_step_inferior_state *displaced;
+ int prepared = displaced_step_prepare (inferior_ptid);
- if (!displaced_step_prepare (inferior_ptid))
+ if (prepared == 0)
{
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog,
@@ -2452,14 +2507,32 @@ resume (enum gdb_signal sig)
discard_cleanups (old_cleanups);
return;
}
+ else if (prepared < 0)
+ {
+ /* Fallback to stepping over the breakpoint in-line. */
+
+ if (target_is_non_stop_p ())
+ stop_all_threads ();
+
+ set_step_over_info (get_regcache_aspace (regcache),
+ regcache_read_pc (regcache), 0);
+
+ step = maybe_software_singlestep (gdbarch, pc);
+
+ insert_breakpoints ();
+ }
+ else if (prepared > 0)
+ {
+ struct displaced_step_inferior_state *displaced;
- /* Update pc to reflect the new address from which we will execute
- instructions due to displaced stepping. */
- pc = regcache_read_pc (get_thread_regcache (inferior_ptid));
+ /* Update pc to reflect the new address from which we will
+ execute instructions due to displaced stepping. */
+ pc = regcache_read_pc (get_thread_regcache (inferior_ptid));
- displaced = get_displaced_stepping_state (ptid_get_pid (inferior_ptid));
- step = gdbarch_displaced_step_hw_singlestep (gdbarch,
- displaced->step_closure);
+ displaced = get_displaced_stepping_state (ptid_get_pid (inferior_ptid));
+ step = gdbarch_displaced_step_hw_singlestep (gdbarch,
+ displaced->step_closure);
+ }
}
/* Do we need to do it the hard way, w/temp breakpoints? */
@@ -2578,8 +2651,8 @@ resume (enum gdb_signal sig)
}
if (debug_displaced
- && use_displaced_stepping (gdbarch)
&& tp->control.trap_expected
+ && use_displaced_stepping (tp)
&& !step_over_info_valid_p ())
{
struct regcache *resume_regcache = get_thread_regcache (tp->ptid);
@@ -7367,8 +7440,7 @@ keep_going_pass_signal (struct execution_control_state *ecs)
watchpoint. The instruction copied to the scratch pad would
still trigger the watchpoint. */
if (remove_bp
- && (remove_wps
- || !use_displaced_stepping (get_regcache_arch (regcache))))
+ && (remove_wps || !use_displaced_stepping (ecs->event_thread)))
{
set_step_over_info (get_regcache_aspace (regcache),
regcache_read_pc (regcache), remove_wps);
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index db7538a..cb69f08 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,5 +1,10 @@
2015-08-07 Pedro Alves <palves@redhat.com>
+ * gdb.base/valgrind-disp-step.c: New file.
+ * gdb.base/valgrind-disp-step.exp: New file.
+
+2015-08-07 Pedro Alves <palves@redhat.com>
+
* gdb.threads/step-over-lands-on-breakpoint.c (wait_threads):
Delete function.
(main): Add alarm. Run an infinite loop instead of calling
diff --git a/gdb/testsuite/gdb.base/valgrind-disp-step.c b/gdb/testsuite/gdb.base/valgrind-disp-step.c
new file mode 100644
index 0000000..baba74e
--- /dev/null
+++ b/gdb/testsuite/gdb.base/valgrind-disp-step.c
@@ -0,0 +1,32 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2015 Free Software Foundation, Inc.
+
+ 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/>. */
+
+static int
+foo (void)
+{
+}
+
+int
+main (void)
+{
+ foo (); /* stop 0 */
+ foo (); /* stop 1 */
+ foo (); /* stop 2 */
+ foo (); /* stop 3 */
+ foo (); /* stop 4 */
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.base/valgrind-disp-step.exp b/gdb/testsuite/gdb.base/valgrind-disp-step.exp
new file mode 100644
index 0000000..d6fd44b
--- /dev/null
+++ b/gdb/testsuite/gdb.base/valgrind-disp-step.exp
@@ -0,0 +1,136 @@
+# Copyright 2012-2015 Free Software Foundation, Inc.
+
+# 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/>.
+
+# Step over breakpoints with displaced stepping on, against Valgrind.
+# We can't really use displaced stepping with Valgrind, so what this
+# really tests is that GDB falls back to in-line stepping
+# automatically instead of getting stuck or crashing.
+
+if [is_remote target] {
+ # The test always runs locally.
+ return 0
+}
+
+standard_testfile .c
+if {[build_executable "failed to build" $testfile $srcfile {debug}] == -1} {
+ return -1
+}
+
+set test "spawn valgrind"
+set cmd "valgrind --vgdb-error=0 $binfile"
+set res [remote_spawn host $cmd]
+if { $res < 0 || $res == "" } {
+ verbose -log "Spawning $cmd failed."
+ unsupported $test
+ return -1
+}
+pass $test
+# Declare GDB now as running.
+set gdb_spawn_id $res
+
+# GDB started by vgdb stops already after the startup is executed, like with
+# non-extended gdbserver. It is also not correct to run/attach the inferior.
+set use_gdb_stub 1
+
+set test "valgrind started"
+# The trailing '.' differs for different memcheck versions.
+gdb_test_multiple "" $test {
+ -re "Memcheck, a memory error detector\\.?\r\n" {
+ pass $test
+ }
+ -re "valgrind: failed to start tool 'memcheck' for platform '.*': No such file or directory" {
+ unsupported $test
+ return -1
+ }
+ -re "valgrind: wrong ELF executable class" {
+ unsupported $test
+ return -1
+ }
+ -re "command not found" {
+ # The spawn succeeded, but then valgrind was not found - e.g. if
+ # we spawned SSH to a remote system.
+ unsupported $test
+ return -1
+ }
+ -re "valgrind: Bad option.*--vgdb-error=0" {
+ # valgrind is not >= 3.7.0.
+ unsupported $test
+ return -1
+ }
+}
+
+set test "vgdb prompt"
+# The trailing '.' differs for different memcheck versions.
+gdb_test_multiple "" $test {
+ -re " (target remote | \[^\r\n\]*/vgdb \[^\r\n\]*)\r\n" {
+ set vgdbcmd $expect_out(1,string)
+ pass $test
+ }
+}
+
+# Do not kill valgrind.
+set valgrind_pid [exp_pid -i [board_info host fileid]]
+unset gdb_spawn_id
+set board [host_info name]
+unset_board_info fileid
+
+clean_restart $testfile
+
+# Make sure we're disconnected, in case we're testing with the
+# native-extended-gdbserver board, where gdb_start/gdb_load spawn
+# gdbserver and connect to it.
+gdb_test "disconnect" ".*"
+
+gdb_test "$vgdbcmd" " in \\.?_start .*" "target remote for vgdb"
+
+gdb_test "monitor v.set gdb_output" "valgrind output will go to gdb.*"
+
+gdb_test_no_output "set displaced-stepping off"
+gdb_breakpoint "main" "breakpoint at main"
+gdb_test "continue" " stop 0 .*" "continue to main"
+delete_breakpoints
+
+set curr_stop 0
+foreach displaced { "off" "on" } {
+ with_test_prefix "displaced $displaced" {
+
+ gdb_test_no_output "set displaced-stepping $displaced"
+
+ foreach go { "once" "twice" } {
+ with_test_prefix $go {
+ gdb_test "break" "Breakpoint .* at .*" "set breakpoint"
+
+ # Whether we should see a warning.
+ set should_warn [expr {$go == "once" && $displaced == "on"}]
+
+ incr curr_stop
+
+ set msg "step over breakpoint"
+ set pattern " stop $curr_stop .*$gdb_prompt $"
+ gdb_test_multiple "next" $msg {
+ -re "warning: disabling displaced stepping.*$pattern" {
+ gdb_assert $should_warn $msg
+ }
+ -re "$pattern" {
+ gdb_assert !$should_warn $msg
+ }
+ }
+ }
+ }
+ }
+}
+
+# Only if valgrind got stuck.
+remote_exec host "kill -9 ${valgrind_pid}"
generated by cgit v1.1 at 2024-11-15 09:01:15 +0000