[RFA-v3] Fix a windows bug if two watchpoints are used

["Pierre Muller" <muller@ics.u-strasbg.fr>]

  Mark never answered that thread,
as a result, this one line patch that fixes
a problem with multiple watches for windows
is not in 7.0 branch :(

The thread started here:
http://sourceware.org/ml/gdb-patches/2009-06/msg00054.html

with 
http://sourceware.org/ml/gdb-patches/2009-06/msg00416.html
containing the final one code line patch.

Mark, could you give your impression?

Thanks in advance,


Pierre Muller
Pascal language support maintainer for GDB

PS: I tested the patch on Compile Farm, on a amd64 linux,
no failure on new watchpoints.exp test,
nor on CVS head nor with patched version.



2009-09-22  Pierre Muller  <muller@ics.u-strasbg.fr>

	* i386-nat.c (i386_stopped_data_address): Also check that
	hitted watch register is not vacant.

	gdb/testsuite ChangeLog entry:
2009-09-22  Pierre Muller  <muller@ics.u-strasbg.fr>
	
	New test for two watchpoints, with disabling of
	the first inserted.
	* testsuite/gdb.base/watchpoints.c: New file.
	* testsuite/gdb.base/watchpoints.exp: New file.

Index: src/gdb/i386-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/i386-nat.c,v
retrieving revision 1.24
diff -u -p -r1.24 i386-nat.c
--- src/gdb/i386-nat.c	2 Jul 2009 17:21:06 -0000	1.24
+++ src/gdb/i386-nat.c	22 Sep 2009 08:25:36 -0000
@@ -555,7 +555,10 @@ i386_stopped_data_address (struct target
 	     that GDB doesn't call the target_stopped_data_address
 	     method except for data watchpoints.  In other words, I'm
 	     being paranoiac.  */
-	  && I386_DR_GET_RW_LEN (i) != 0)
+	  && I386_DR_GET_RW_LEN (i) != 0
+	  /* This third condition makes sure DRi is not vacant, this
+	     avoids false positives in windows-nat.c.  */
+	  && !I386_DR_VACANT (i))
 	{
 	  addr = dr_mirror[i];
 	  rc = 1;
Index: src/gdb/testsuite/gdb.base/watchpoints.c
===================================================================
RCS file: testsuite/gdb.base/watchpoints.c
diff -N testsuite/gdb.base/watchpoints.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/gdb/testsuite/gdb.base/watchpoints.c	25 Jun 2009 22:44:17 -0000
@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <unistd.h>
+/*
+ * This source is mainly to test
+ * what happens when a watchpoint is removed
+ * while another watchpoint, inserted later is
+ * left active.
+ */
+
+int count = -1;
+int ival1 = -1;
+int ival2 = -1;
+int ival3 = -1;
+int ival4 = -1;
+
+int 
+main ()
+{
+#ifdef usestubs
+  set_debug_traps();
+  breakpoint();
+#endif
+
+  for (count = 0; count < 4; count++) {
+    ival1 = count; ival2 = count;
+    ival3 = count; ival4 = count;
+  }
+
+  ival1 = count; ival2 = count;  /* Outside loop */
+  ival3 = count; ival4 = count;
+
+  return 0;
+}
Index: src/gdb/testsuite/gdb.base/watchpoints.exp
===================================================================
RCS file: testsuite/gdb.base/watchpoints.exp
diff -N testsuite/gdb.base/watchpoints.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/gdb/testsuite/gdb.base/watchpoints.exp	25 Jun 2009 22:44:17 -0000
@@ -0,0 +1,101 @@
+# 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 file was written by Pierre Muller. (muller@ics.u-strasbg.fr)
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set prms_id 0
+set bug_id 0
+
+set testfile "watchpoints"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+set wp_set 1
+
+if [get_compiler_info ${binfile}] {
+    return -1
+}
+
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable
{debug}] != "" } {
+     untested watchpoint.exp
+     return -1
+}
+
+# Start with a fresh gdb.
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load $binfile
+
+    runto_main
+    gdb_test "watch ival1" "" ""
+    gdb_test "watch ival3" "" ""
+
+    set timeout 600
+
+    gdb_test "cont" "Continuing.*\[Ww\]atchpoint.*ival1.*Old value =
-1.*New value = 0.*ival1 = count; ival2 = count;.*" "watchpoint hit, first
time"
+
+    gdb_test "cont" "Continuing.*\[Ww\]atchpoint.*ival3.*Old value =
-1.*New value = 0.*ival3 = count; ival4 = count;.*" "watchpoint hit, first
time"
+
+    # Check that the ival3 hit count is reported correctly
+    gdb_test "info break" ".*watchpoint\[ \t\]+keep\[ \t\]+y\[
\t\]+ival3\r\n\[ \t]+breakpoint already hit 1 time.*" "Watchpoint hit count
is 1"
+
+    # Continue until the next change for ival1, from 0 to 1.
+    gdb_test "cont" "Continuing.*\[Ww\]atchpoint.*ival1.*Old value = 0.*New
value = 1.*ival1 = count; ival2 = count;.*" "watchpoint ival1 hit, second
time"
+
+    # Check that the hit count for ival1 is reported correctly
+    gdb_test "info break" ".*watchpoint\[ \t\]+keep\[ \t\]+y\[
\t\]+ival1\r\n\[ \t]+breakpoint already hit 2 times.*" "Watchpoint ival1 hit
count is 2"
+
+    # Continue until the next change for ival3, from 0 to 1.
+    gdb_test "cont" "Continuing.*\[Ww\]atchpoint.*ival3.*Old value = 0.*New
value = 1.*ival3 = count; ival4 = count;.*" "watchpoint hit, second time"
+
+    # Check that the hit count is reported correctly
+    gdb_test "info break" ".*watchpoint\[ \t\]+keep\[ \t\]+y\[
\t\]+ival3\r\n\[ \t]+breakpoint already hit 2 times.*" "Watchpoint hit count
is 2"
+
+    # Continue until the next change, from 1 to 2.
+    gdb_test "cont" "Continuing.*\[Ww\]atchpoint.*ival1.*Old value = 1.*New
value = 2.*ival1 = count; ival2 = count;.*" "watchpoint ival1 hit, third
time"
+
+    # Check that the hit count is reported correctly
+    gdb_test "info break" ".*watchpoint\[ \t\]+keep\[ \t\]+y\[
\t\]+ival1\r\n\[ \t]+breakpoint already hit 3 times.*" "Watchpoint ival1 hit
count is 3"
+    # Disable ival1 watchpoint
+    gdb_test "disable 2" "" ""
+ 
+    # Continue until the next change, from 1 to 2.
+    gdb_test "cont" "Continuing.*\[Ww\]atchpoint.*ival3.*Old value = 1.*New
value = 2.*ival3 = count; ival4 = count;.*" "watchpoint hit, third time"
+
+    # Check that the hit count is reported correctly
+    gdb_test "info break" ".*watchpoint\[ \t\]+keep\[ \t\]+y\[
\t\]+ival3\r\n\[ \t]+breakpoint already hit 3 times.*" "Watchpoint hit count
is 3"
+    
+    # Continue until the next change, from 2 to 3.
+    gdb_test "cont" "Continuing.*\[Ww\]atchpoint.*ival3.*Old value = 2.*New
value = 3.*ival3 = count; ival4 = count;.*" "watchpoint hit, fourth time"
+
+    # Check that the hit count is reported correctly
+    gdb_test "info break" ".*watchpoint\[ \t\]+keep\[ \t\]+y\[
\t\]+ival3\r\n\[ \t]+breakpoint already hit 4 times.*" "Watchpoint hit count
is 4"
+
+    # Continue until the next change, from 3 to 4.
+    # Note that this one is outside the loop.
+
+    gdb_test "cont" "Continuing.*\[Ww\]atchpoint.*ival3.*Old value = 3.*New
value = 4.*ival3 = count; ival4 = count;.*" "watchpoint hit, fifth time"
+
+    # Check that the hit count is reported correctly
+    gdb_test "info break" ".*watchpoint\[ \t\]+keep\[ \t\]+y\[
\t\]+ival3\r\n\[ \t]+breakpoint already hit 5 times.*" "Watchpoint hit count
is 5"
+
+