[commit] Dandling memory pointers in Ada catchpoints with GDB/MI.
Joel Brobecker
brobecker@adacore.com
Mon Nov 11 15:34:00 GMT 2013
Hello,
When using the GDB/MI commands to insert a catchpoint on a specific
Ada exception, any re-evaluation of that catchpoint (for instance
a re-evaluation performed after a shared library got mapped by the
inferior) fails. For instance, with any Ada program:
(gdb)
-catch-exception -e program_error
^done,bkptno="1",bkpt={[...]}
(gdb)
-exec-run
=thread-group-started,id="i1",pid="28315"
=thread-created,id="1",group-id="i1"
^running
*running,thread-id="all"
(gdb)
=library-loaded,[...]
&"warning: failed to reevaluate internal exception condition for catchpoint 1: No definition of \"exec\" in current context.\n"
&"warning: failed to reevaluate internal exception condition for catchpoint 1: No definition of \"exec\" in current context.\n"
[...]
The same is true if using an Ada exception catchpoint.
The problem comes from the fact that that we deallocate the strings
given as arguments to create_ada_exception_catchpoint, while the latter
just makes shallow copies of those strings, thus creating dandling
pointers.
This patch fixes the issue by passing freshly allocated strings to
create_ada_exception_catchpoint, while at the same time updating
create_ada_exception_catchpoint's documentation to make it clear
that deallocating the strings is no longer the responsibility of
the caller.
gdb/ChangeLog:
* ada-lang.c (create_ada_exception_catchpoint): Enhance
the documentation of fields "except_string" and "condition".
* mi/mi-cmd-catch.c (mi_cmd_catch_assert): Reallocate
CONDITION on the heap before passing it to
create_ada_exception_catchpoint.
(mi_cmd_catch_exception): Likewise for EXCEPTION_NAME and
CONDITION.
gdb/testsuite/ChangeLog:
* gdb.ada/mi_ex_cond: New testcase.
Tested on x86_64-linux. The "-break-list" test FAILs without
this patch. Checked in.
Thanks,
--
Joel
---
gdb/ada-lang.c | 14 +++--
gdb/mi/mi-cmd-catch.c | 10 ++++
gdb/testsuite/gdb.ada/mi_ex_cond.exp | 94 ++++++++++++++++++++++++++++++++
gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb | 29 ++++++++++
gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads | 18 ++++++
5 files changed, 160 insertions(+), 5 deletions(-)
create mode 100644 gdb/testsuite/gdb.ada/mi_ex_cond.exp
create mode 100644 gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb
create mode 100644 gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 4b55460..7817132 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -12170,11 +12170,15 @@ ada_exception_sal (enum ada_exception_catchpoint_kind ex, char *excep_string,
EX_KIND is the kind of exception catchpoint to be created.
- EXCEPT_STRING, if not NULL, indicates the name of the exception
- to which this catchpoint applies. If NULL, this catchpoint is
- expected to trigger for all exceptions.
-
- COND_STRING, if not NULL, is the catchpoint condition.
+ If EXCEPT_STRING is NULL, this catchpoint is expected to trigger
+ for all exceptions. Otherwise, EXCEPT_STRING indicates the name
+ of the exception to which this catchpoint applies. When not NULL,
+ the string must be allocated on the heap, and its deallocation
+ is no longer the responsibility of the caller.
+
+ COND_STRING, if not NULL, is the catchpoint condition. This string
+ must be allocated on the heap, and its deallocation is no longer
+ the responsibility of the caller.
TEMPFLAG, if nonzero, means that the underlying breakpoint
should be temporary.
diff --git a/gdb/mi/mi-cmd-catch.c b/gdb/mi/mi-cmd-catch.c
index 23e30d0..bcfc1ba 100644
--- a/gdb/mi/mi-cmd-catch.c
+++ b/gdb/mi/mi-cmd-catch.c
@@ -81,6 +81,10 @@ mi_cmd_catch_assert (char *cmd, char *argv[], int argc)
error (_("Invalid argument: %s"), argv[oind]);
setup_breakpoint_reporting ();
+ /* create_ada_exception_catchpoint needs CONDITION to be xstrdup'ed,
+ and will assume control of its lifetime. */
+ if (condition != NULL)
+ condition = xstrdup (condition);
create_ada_exception_catchpoint (gdbarch, ada_catch_assert,
NULL, condition, temp, enabled, 0);
}
@@ -154,6 +158,12 @@ mi_cmd_catch_exception (char *cmd, char *argv[], int argc)
error (_("\"-e\" and \"-u\" are mutually exclusive"));
setup_breakpoint_reporting ();
+ /* create_ada_exception_catchpoint needs EXCEPTION_NAME and CONDITION
+ to be xstrdup'ed, and will assume control of their lifetime. */
+ if (exception_name != NULL)
+ exception_name = xstrdup (exception_name);
+ if (condition != NULL)
+ condition = xstrdup (condition);
create_ada_exception_catchpoint (gdbarch, ex_kind,
exception_name, condition,
temp, enabled, 0);
diff --git a/gdb/testsuite/gdb.ada/mi_ex_cond.exp b/gdb/testsuite/gdb.ada/mi_ex_cond.exp
new file mode 100644
index 0000000..9144102
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/mi_ex_cond.exp
@@ -0,0 +1,94 @@
+# Copyright 2013 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/>.
+
+load_lib "ada.exp"
+
+standard_ada_testfile foo
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug additional_flags=-bargs additional_flags=-static additional_flags=-margs ]] != "" } {
+ return -1
+}
+
+# # Some global variables used to simplify the maintenance of some of
+# # the regular expressions below.
+set any_nb "\[0-9\]+"
+set eol "\[\r\n\]+"
+
+# Before going any further, verify that we can insert exception
+# catchpoints... That way, we won't have to do this while doing
+# the actual GDB/MI testing.
+
+clean_restart ${testfile}
+
+if ![runto_main] then {
+ fail "Cannot run to main, testcase aborted"
+ return 0
+}
+
+set msg "insert catchpoint on all Ada exceptions"
+gdb_test_multiple "catch exception" $msg {
+ -re "Catchpoint $any_nb: all Ada exceptions$eol$gdb_prompt $" {
+ pass $msg
+ }
+ -re "Your Ada runtime appears to be missing some debugging information.*\[\r\n\]+$gdb_prompt $" {
+ # If the runtime was not built with enough debug information,
+ # or if it was stripped, we can not test exception
+ # catchpoints.
+ unsupported $msg
+ return -1
+ }
+}
+
+# Now, we can start the GDB/MI testing itself...
+
+load_lib mi-support.exp
+set MIFLAGS "-i=mi"
+
+gdb_exit
+if [mi_gdb_start] {
+ continue
+}
+
+mi_delete_breakpoints
+mi_gdb_reinitialize_dir $srcdir/$subdir
+mi_gdb_load ${binfile}
+
+# And finally, the meat of the testcase... Insert an Ada exception
+# catchpoint that uses both conditions and exception name.
+
+mi_gdb_test "-catch-exception -c \"i = 2\" -e constraint_error" \
+ "\\^done,bkptno=\"$decimal\",bkpt={.*disp=\"keep\",enabled=\"y\",addr=\"$hex\",what=\"`constraint_error' Ada exception\",.*,cond=\"i = 2\",.*}" \
+ "catch C_E if i = 2"
+
+# It is important that we start the program's execution after having
+# inserted the exception catchpoint above. We want to verify that
+# we are able to re-evaluate the exception catchpoint exception
+# address and stop condition without problems when new shared libraries
+# get mapped (during program startup).
+
+mi_run_cmd
+
+mi_expect_stop \
+ "breakpoint-hit\",disp=\"keep\",bkptno=\"$any_nb\",exception-name=\"CONSTRAINT_ERROR" \
+ "foo" "" ".*" ".*" \
+ ".*" \
+ "run to exception catchpoint hit"
+
+# Make sure that any of the catchpoint re-evaluations didn't cause
+# a clobbering of some of the exeption's info.
+
+mi_gdb_test "-break-list" \
+ "\\^done,.*,what=\"`constraint_error' Ada exception\",.*,cond=\"i = 2\",.*" \
+ "-break-list"
diff --git a/gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb b/gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb
new file mode 100644
index 0000000..9db1233
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/mi_ex_cond/foo.adb
@@ -0,0 +1,29 @@
+-- Copyright 2013 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/>.
+
+with Pck; use Pck;
+
+procedure Foo is
+begin
+ while I <= 3 loop
+ begin
+ raise Constraint_Error;
+ exception
+ when others =>
+ null;
+ end;
+ I := I + 1;
+ end loop;
+end Foo;
diff --git a/gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads b/gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads
new file mode 100644
index 0000000..0ac131c
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/mi_ex_cond/pck.ads
@@ -0,0 +1,18 @@
+-- Copyright 2013 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/>.
+
+package Pck is
+ I : Integer := 1;
+end Pck;
--
1.8.1.2
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