[RFA/7.8] user breakpoint not inserted if software-single-step at same location

[Pedro Alves]

On 05/30/2014 04:57 PM, Pedro Alves wrote:

> Ah, I just went ahead and tried that against my by sss-on-x86
> branch, and indeed it fails here, while it passes on
> pristine mainline / hardware stepping.

I now filed bug 17000 for this , and went ahead and pushed the test
in, kfailed.

8<--------------
Subject: [PATCH] PR breakpoints/17000: user breakpoint not inserted if
 software-single-step at same location - test

GDB gets confused when removing a software single-step breakpoint that
is at the same address as another breakpoint.  Add a kfailed test.

gdb/testsuite/
2014-05-30  Pedro Alves  <palves@redhat.com>

	PR breakpoints/17000
	* gdb.base/sss-bp-on-user-bp.c: New file.
	* gdb.base/sss-bp-on-user-bp.exp: New file.
---
 gdb/testsuite/ChangeLog                      |  6 ++++
 gdb/testsuite/gdb.base/sss-bp-on-user-bp.c   | 30 ++++++++++++++++
 gdb/testsuite/gdb.base/sss-bp-on-user-bp.exp | 52 ++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+)
 create mode 100644 gdb/testsuite/gdb.base/sss-bp-on-user-bp.c
 create mode 100644 gdb/testsuite/gdb.base/sss-bp-on-user-bp.exp

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index b09e86e..334fd83 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2014-05-30  Pedro Alves  <palves@redhat.com>
+
+	PR breakpoints/17000
+	* gdb.base/sss-bp-on-user-bp.c: New file.
+	* gdb.base/sss-bp-on-user-bp.exp: New file.
+
 2014-05-30  David Blaikie  <dblaikie@gmail.com>
 
 	* gdb.opt/inline-break.c: Fix clang compatibility by specifying
diff --git a/gdb/testsuite/gdb.base/sss-bp-on-user-bp.c b/gdb/testsuite/gdb.base/sss-bp-on-user-bp.c
new file mode 100644
index 0000000..ff82051
--- /dev/null
+++ b/gdb/testsuite/gdb.base/sss-bp-on-user-bp.c
@@ -0,0 +1,30 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2014 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 <signal.h>
+#include <unistd.h>
+
+int
+main (void)
+{
+  /* Assume writes to integers compile to a single instruction.  */
+  volatile int i = 0;
+
+  i = 1;     /* set foo break here */
+  i = 2;     /* set bar break here */
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/sss-bp-on-user-bp.exp b/gdb/testsuite/gdb.base/sss-bp-on-user-bp.exp
new file mode 100644
index 0000000..62415e7
--- /dev/null
+++ b/gdb/testsuite/gdb.base/sss-bp-on-user-bp.exp
@@ -0,0 +1,52 @@
+# Copyright 2014 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/>.
+
+# Test that removing a single-step breakpoint that is placed at the
+# same address as another regular breakpoint leaves the regular
+# breakpoint inserted.
+
+standard_testfile
+set executable ${testfile}
+
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
+    return -1
+}
+
+if ![runto_main] then {
+    fail "Can't run to main"
+    return 0
+}
+
+gdb_breakpoint [gdb_get_line_number "set foo break here"]
+gdb_continue_to_breakpoint "first breakpoint" ".* set foo break here .*"
+
+gdb_breakpoint [gdb_get_line_number "set bar break here"]
+
+# So that GDB doesn't try to remove the regular breakpoint when the
+# step finishes.
+gdb_test_no_output "set breakpoint always-inserted on"
+
+# On software single-step targets, this step will want to momentarily
+# place a single-step breakpoint over the bar breakpoint, and then
+# remove it.  But, a regular breakpoint is planted there already, and
+# with always-inserted on, should remain planted when the step
+# finishes.
+gdb_test "si" "Breakpoint .* bar break .*"
+
+# If the breakpoint is still correctly inserted, then this jump should
+# re-trigger it.  Otherwise, GDB will lose control and the program
+# will exit.
+setup_kfail "breakpoints/17000" "*-*-*"
+gdb_test "jump *\$pc" "Breakpoint .* bar break .*"
-- 
1.9.0