gdb/

* breakpoint.h (struct breakpoint) <watchpoint_thread>: New field.
	* breakpoint.c (watchpoint_in_thread_scope): New.
	(update_watchpoint): Skip if the local watchpoint's thread doesn't
	match the current thread, or if the current thread is running.
	(watchpoint_check): Ditto.
	(watch_command_1): Set the watchpoint's watchpoint_thread field.

	gdb/testsuite/
	* gdb.threads/local-watch-wrong-thread.c,
	gdb.threads/local-watch-wrong-thread.exp: New files.

gdb/ChangeLog

@@ -1,3 +1,12 @@
+2009-11-21  Pedro Alves  <pedro@codesourcery.com>
+
+	* breakpoint.h (struct breakpoint) <watchpoint_thread>: New field.
+	* breakpoint.c (watchpoint_in_thread_scope): New.
+	(update_watchpoint): Skip if the local watchpoint's thread doesn't
+	match the current thread, or if the current thread is running.
+	(watchpoint_check): Ditto.
+	(watch_command_1): Set the watchpoint's watchpoint_thread field.
+
 2009-11-20  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	* breakpoint.c (bp_location_compare): Change parameter a to ap and b to

gdb/breakpoint.c

@@ -985,6 +985,24 @@ fetch_watchpoint_value (struct expression *exp, struct value **valp,
     }
 }
 
+/* Assuming that B is a watchpoint: returns true if the current thread
+   and its running state are safe to evaluate or update watchpoint B.
+   Watchpoints on local expressions need to be evaluated in the
+   context of the thread that was current when the watchpoint was
+   created, and, that thread needs to be stopped to be able to select
+   the correct frame context.  Watchpoints on global expressions can
+   be evaluated on any thread, and in any state.  It is presently left
+   to the target allowing memory accesses when threads are
+   running.  */
+
+static int
+watchpoint_in_thread_scope (struct breakpoint *b)
+{
+  return (ptid_equal (b->watchpoint_thread, null_ptid)
+	  || (ptid_equal (inferior_ptid, b->watchpoint_thread)
+	      && !is_executing (inferior_ptid)));
+}
+
 /* Assuming that B is a watchpoint:
    - Reparse watchpoint expression, if REPARSE is non-zero
    - Evaluate expression and store the result in B->val
@@ -1043,6 +1061,12 @@ update_watchpoint (struct breakpoint *b, int reparse)
   bpstat bs;
   struct program_space *frame_pspace;
 
+  /* If this is a local watchpoint, we only want to check if the
+     watchpoint frame is in scope if the current thread is the thread
+     that was used to create the watchpoint.  */
+  if (!watchpoint_in_thread_scope (b))
+    return;
+
   /* We don't free locations.  They are stored in bp_location array and
      update_global_locations will eventually delete them and remove
      breakpoints if needed.  */
@@ -3124,6 +3148,12 @@ watchpoint_check (void *p)
 
   b = bs->breakpoint_at->owner;
 
+  /* If this is a local watchpoint, we only want to check if the
+     watchpoint frame is in scope if the current thread is the thread
+     that was used to create the watchpoint.  */
+  if (!watchpoint_in_thread_scope (b))
+    return WP_VALUE_NOT_CHANGED;
+
   if (b->exp_valid_block == NULL)
     within_current_scope = 1;
   else
@@ -7190,9 +7220,15 @@ watch_command_1 (char *arg, int accessflag, int from_tty)
     b->cond_string = 0;
 
   if (frame)
-    b->watchpoint_frame = get_frame_id (frame);
+    {
+      b->watchpoint_frame = get_frame_id (frame);
+      b->watchpoint_thread = inferior_ptid;
+    }
   else
-    b->watchpoint_frame = null_frame_id;
+    {
+      b->watchpoint_frame = null_frame_id;
+      b->watchpoint_thread = null_ptid;
+    }
 
   if (scope_breakpoint != NULL)
     {

gdb/breakpoint.h

@@ -457,6 +457,11 @@ struct breakpoint
        should be evaluated on the outermost frame.  */
     struct frame_id watchpoint_frame;
 
+    /* Holds the thread which identifies the frame this watchpoint
+       should be considered in scope for, or `null_ptid' if the
+       watchpoint should be evaluated in all threads.  */
+    ptid_t watchpoint_thread;
+
     /* For hardware watchpoints, the triggered status according to the
        hardware.  */
     enum watchpoint_triggered watchpoint_triggered;

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2009-11-21  Pedro Alves  <pedro@codesourcery.com>
+
+	* gdb.threads/local-watch-wrong-thread.c,
+	gdb.threads/local-watch-wrong-thread.exp: New files.
+
 2009-11-21  Pedro Alves  <pedro@codesourcery.com>
 
 	* gdb.cp/cplusfuncs.exp (info_func_regexp, print_addr): Don't

gdb/testsuite/gdb.threads/local-watch-wrong-thread.c

@@ -0,0 +1,88 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2002, 2003, 2004, 2007, 2008, 2009 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/>.
+
+*/
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+unsigned int args[2];
+int trigger = 0;
+
+void *
+thread_function0 (void *arg)
+{
+  int my_number =  (long) arg;
+  volatile int *myp = (volatile int *) &args[my_number];
+
+  while (*myp > 0)
+    {
+      (*myp) ++;
+      usleep (1);  /* Loop increment 1.  */
+    }
+
+  return NULL;
+}
+
+void *
+thread_function0_1 (void *arg)
+{
+  void *ret = thread_function0 (arg);
+
+  return ret; /* set breakpoint here */
+}
+
+void *
+thread_function1 (void *arg)
+{
+  int my_number =  (long) arg;
+
+  volatile int *myp = (volatile int *) &args[my_number];
+
+  while (*myp > 0)
+    {
+      (*myp) ++;
+      usleep (1);  /* Loop increment 2.  */
+    }
+
+  return NULL;
+}
+
+int
+main ()
+{
+  int res;
+  pthread_t threads[2];
+  void *thread_result;
+  long i = 0;
+
+  args[i] = 1; /* Init value.  */
+  res = pthread_create (&threads[i], NULL,
+			thread_function0_1,
+			(void *) i);
+
+  i++;
+  args[i] = 1; /* Init value.  */
+  res = pthread_create(&threads[i], NULL,
+		       thread_function1,
+		       (void *) i);
+
+  pthread_join (threads[0], &thread_result);
+  pthread_join (threads[1], &thread_result);
+  exit(EXIT_SUCCESS);
+}

gdb/testsuite/gdb.threads/local-watch-wrong-thread.exp

@@ -0,0 +1,122 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 2009 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/>.
+
+# This test verifies that a local watchpoint isn't deleted when a
+# thread other than the thread the local watchpoint was set in stops
+# for a breakpoint.
+
+if [target_info exists gdb,no_hardware_watchpoints] {
+    return 0;
+}
+
+set testfile "local-watch-wrong-thread"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+if {[gdb_compile_pthreads \
+	 "${srcdir}/${subdir}/${srcfile}" \
+	 "${binfile}" executable {debug} ] != "" } {
+    return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+gdb_test "set can-use-hw-watchpoints 1" "" ""
+
+if ![runto_main] then {
+    fail "Can't run to main"
+    return
+}
+
+set inc_line_1 [gdb_get_line_number "Loop increment 1"]
+set inc_line_2 [gdb_get_line_number "Loop increment 2"]
+set bkpt_here [gdb_get_line_number "set breakpoint here"]
+
+# Run to the loop within thread_function0, so we can set our local
+# watchpoint.
+gdb_test "break ${srcfile}:${inc_line_1}" \
+    "Breakpoint 2 at .*: file .*${srcfile}, line .*" \
+    "breakpoint on thread_function0"
+
+gdb_test "continue" \
+    ".*Breakpoint 2.*thread_function0.*" \
+    "continue to thread_function0"
+
+delete_breakpoints
+
+# Set the local watchpoint, and confirm that it traps as expected.
+gdb_test "watch *myp" \
+    "Hardware watchpoint 3\: \\*myp.*" \
+    "set local watchpoint on *myp"
+
+gdb_test "continue" \
+    "Hardware watchpoint.*Old value.*New value.*thread_function0.*" \
+    "local watchpoint triggers"
+
+delete_breakpoints
+
+# Recreate the watchpoint, but this time with a condition we know
+# won't trigger.  This is so the watchpoint is inserted, and the
+# target reports events, but GDB doesn't stop for them.  We want to
+# hit the breakpoints on the other thread, and make sure this
+# watchpoint isn't deleted then.
+gdb_test "watch *myp if trigger != 0" \
+    "Hardware watchpoint 4\: \\*myp.*" \
+    "set local watchpoint on *myp, with false conditional"
+
+# Run to a breakpoint on a different thread.  The previous local
+# watchpoint should not be deleted with the standard 'the program has
+# left the block in which its expression is valid', because the
+# thread_function0 thread should still be running in the loop.
+gdb_test "break ${srcfile}:${inc_line_2}" \
+    "Breakpoint 5 at .*: file .*${srcfile}, line .*" \
+    "breakpoint on the other thread"
+
+gdb_test "continue" \
+    "Breakpoint 5, thread_function1.*" \
+    "the other thread stopped on breakpoint"
+
+# Delete the new breakpoint, we don't need it anymore.
+gdb_test "delete 5" "" ""
+
+# Check if the local watchpoint hasn't been deleted (is still listed).
+# This is simpler to check than expecting 'the program has left ...',
+# and, is immune to string changes in that warning.
+gdb_test "info breakpoints" \
+    ".*4.*hw watchpoint.*keep.*y.*\\*myp.*" \
+    "local watchpoint is still in breakpoint list"
+
+# Make the watchpoint condition eval true.
+gdb_test "set trigger=1" "" "let local watchpoint trigger"
+
+gdb_test "continue" \
+    "Hardware watchpoint.*Old value.*New value.*thread_function0.*" \
+    "local watchpoint still triggers"
+
+# Confirm that the local watchpoint is indeed deleted when
+# thread_function0 returns.
+gdb_test "set *myp=0" "" "let thread_function0 return"
+
+gdb_test "break ${srcfile}:${bkpt_here}" \
+    "Breakpoint 6 at .*: file .*${srcfile}, line .*" \
+    "breakpoint on thread_function0's caller"
+
+gdb_test "continue" \
+    ".*Watchpoint.*deleted.*" \
+    "local watchpoint automatically deleted"