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Re: [PATCH] Failure to stop at duplicate breakpoints
- From: "Andrew Burgess" <aburgess at broadcom dot com>
- To: "gdb-patches at sourceware dot org" <gdb-patches at sourceware dot org>
- Cc: "Sergio Durigan Junior" <sergiodj at redhat dot com>
- Date: Fri, 21 Sep 2012 00:20:50 +0100
- Subject: Re: [PATCH] Failure to stop at duplicate breakpoints
- References: <505B31C2.5010203@broadcom.com> <m31uhwfsh5.fsf@redhat.com>
On 20/09/2012 7:40 PM, Sergio Durigan Junior wrote:
> On Thursday, September 20 2012, Andrew Burgess wrote:
>
>> When two breakpoints are created at the same location, one of them is
>> marked as a duplicate. When gdb inserts the breakpoints we only
>> really insert one breakpoint at any unique location.
>>
>> By creating duplicate breakpoints and deleting or disabling them in
>> the right order it is possible to get into a state where gdb has a
>> single breakpoint with a single location, but that location is marked
>> duplicate and so is never inserted, with the result we don't stop at
>> the breakpoint.
>>
>> Patch and test included below.
>
> Thanks for the patches, but your mail client messed with them, probably.
> They are malformed in several places.
Sorry for the badly formatted patch, I believe I've fixed the issue, and
the version below should be more readable.
OK to apply?
Thanks,
Andrew
gdb/ChangeLog
2012-09-20 Andrew Burgess <aburgess@broadcom.com>
* breakpoint.c (update_global_location_list): Ignore previous
duplicate status of a breakpoint when starting a new scan for
duplicate breakpoints.
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index b841bcd..f771d06 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -12463,7 +12463,7 @@ update_global_location_list (int should_insert)
struct bp_location **loc_first_p;
b = loc->owner;
- if (!should_be_inserted (loc)
+ if (!unduplicated_should_be_inserted (loc)
|| !breakpoint_address_is_meaningful (b)
/* Don't detect duplicate for tracepoint locations because they are
never duplicated. See the comments in field `duplicate' of
gdb/testsuite/ChangeLog
2012-09-20 Andrew Burgess <aburgess@broadcom.com>
* gdb.base/duplicate-bp.c: New file.
* gdb.base/duplicate-bp.exp: New file.
diff --git a/gdb/testsuite/gdb.base/duplicate-bp.c b/gdb/testsuite/gdb.base/duplicate-bp.c
new file mode 100644
index 0000000..50145b4
--- /dev/null
+++ b/gdb/testsuite/gdb.base/duplicate-bp.c
@@ -0,0 +1,23 @@
+void
+spacer ()
+{
+ /* Nothing. */
+}
+
+void
+breakpt ()
+{
+ /* Nothing. */
+}
+
+int
+main ()
+{
+ spacer ();
+
+ breakpt ();
+
+ spacer ();
+
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.base/duplicate-bp.exp b/gdb/testsuite/gdb.base/duplicate-bp.exp
new file mode 100644
index 0000000..021aa30
--- /dev/null
+++ b/gdb/testsuite/gdb.base/duplicate-bp.exp
@@ -0,0 +1,137 @@
+# Copyright 2012 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/>.
+
+if { [prepare_for_testing duplicate-bp.exp "duplicate-bp" {duplicate-bp.c} {debug nowarnings}] } {
+ return -1
+}
+set srcfile "duplicate-bp.c"
+
+# Setup for the test, create COUNT breakpoints at the function BREAKPT.
+proc test_setup { count } {
+ upvar srcfile srcfile
+
+ clean_restart duplicate-bp
+
+ if ![runto_main] then {
+ fail "can't run to main"
+ return 0
+ }
+
+ for {set i 1} {$i <= $count} {incr i} {
+ gdb_breakpoint "breakpt"
+ gdb_test_no_output "set \$bp_num_${i} = \$bpnum"
+ }
+
+ gdb_test "step" "spacer \\(\\) at .*$srcfile:\[0-9\]+.*"
+
+ return 1
+}
+
+
+# Test 1: Create two breakpoints at BREAKPT. Delete #1 and expect to stop
+# at #2.
+test_setup 2
+
+gdb_test_no_output {delete $bp_num_1}
+
+gdb_test continue "Continuing\\..*Breakpoint \[0-9\]+, breakpt \\(\\) at .*$srcfile:\[0-9\]+.*" \
+ "delete #1, stop at #2"
+
+# Test 2: Create two breakpoints at BREAKPT. Delete #2 and expect to stop
+# at #1.
+test_setup 2
+
+gdb_test_no_output {delete $bp_num_2}
+
+gdb_test continue "Continuing\\..*Breakpoint \[0-9\]+, breakpt \\(\\) at .*$srcfile:\[0-9\]+.*" \
+ "delete #2, stop at #1"
+
+# Test 3: Create three breakpoints at BREAKPT. Disable #1, delete #2,
+# expect to stop at #3.
+test_setup 3
+
+gdb_test_no_output {disable $bp_num_1}
+
+gdb_test "step" ".*"
+
+gdb_test_no_output {delete $bp_num_2}
+
+gdb_test continue "Continuing\\..*Breakpoint \[0-9\]+, breakpt \\(\\) at .*$srcfile:\[0-9\]+.*" \
+ "disable #1, delete #2, stop at #3"
+
+# Test 4: Create three breakpoints at BREAKPT. Disable #2, delete #1,
+# expect to stop at #3.
+test_setup 3
+
+gdb_test_no_output {disable $bp_num_2}
+
+gdb_test "step" ".*"
+
+gdb_test_no_output {delete $bp_num_1}
+
+gdb_test continue "Continuing\\..*Breakpoint \[0-9\]+, breakpt \\(\\) at .*$srcfile:\[0-9\]+.*" \
+ "disable #2, delete #1, stop at #3"
+
+# Test 5: Create three breakpoints at BREAKPT. Disable #1, delete #3,
+# expect to stop at #1.
+test_setup 3
+
+gdb_test_no_output {disable $bp_num_1}
+
+gdb_test "step" ".*"
+
+gdb_test_no_output {delete $bp_num_3}
+
+gdb_test continue "Continuing\\..*Breakpoint \[0-9\]+, breakpt \\(\\) at .*$srcfile:\[0-9\]+.*" \
+ "disable #1, delete #3, stop at #1"
+
+# Test 6: Create three breakpoints at BREAKPT. Disable #3, delete #1,
+# expect to stop at #2.
+test_setup 3
+
+gdb_test_no_output {disable $bp_num_3}
+
+gdb_test "step" ".*"
+
+gdb_test_no_output {delete $bp_num_1}
+
+gdb_test continue "Continuing\\..*Breakpoint \[0-9\]+, breakpt \\(\\) at .*$srcfile:\[0-9\]+.*" \
+ "disable #3, delete #1, stop at #2"
+
+# Test 7: Create three breakpoints at BREAKPT. Disable #2, delete #3,
+# expect to stop at #1.
+test_setup 3
+
+gdb_test_no_output {disable $bp_num_2}
+
+gdb_test "step" ".*"
+
+gdb_test_no_output {delete $bp_num_3}
+
+gdb_test continue "Continuing\\..*Breakpoint \[0-9\]+, breakpt \\(\\) at .*$srcfile:\[0-9\]+.*" \
+ "disable #2, delete #3, stop at #1"
+
+# Test 6: Create three breakpoints at BREAKPT. Disable #3, delete #2,
+# expect to stop at #1.
+test_setup 3
+
+gdb_test_no_output {disable $bp_num_3}
+
+gdb_test "step" ".*"
+
+gdb_test_no_output {delete $bp_num_2}
+
+gdb_test continue "Continuing\\..*Breakpoint \[0-9\]+, breakpt \\(\\) at .*$srcfile:\[0-9\]+.*" \
+ "disable #3, delete #2, stop at #1"