Re: [patch] Fix `return' of long/long-long results with no debuginfo

Jan Kratochvil
2009-02-12T09:41:52Z

On Wed, 11 Feb 2009 23:44:21 +0100, Mark Kettenis wrote:
> Thinking a bit more of this now, things all depend on the calling
> convention. I'm not convinced casting to `long long' is safe in all
> cases, especially on 32-bit big-endian machines. It really might do
> the wrong thing there, exposing garbage or the wrong 32 bits of the
> 64-bit value.
>
> The 'int' case is really special in a sense, very much because of the
> K&R heritage. It has to work for all types that are sizeof(int) or
> smaller.

OK to check-in this patch?

Regression-tested on x86_64-unknown-linux-gnu.

Thanks,
Jan

gdb/
2009-02-12 Mark Kettenis <kettenis@gnu.org>

* stack.c (return_command): Returned type for functions with no debug
info is now the type of user specified expression.

gdb/testsuite/
2009-02-12 Jan Kratochvil <jan.kratochvil@redhat.com>

* gdb.base/return-nodebug.exp, gdb.base/return-nodebug.c: New.

--- gdb/stack.c 11 Feb 2009 16:07:28 -0000 1.185
+++ gdb/stack.c 12 Feb 2009 09:24:18 -0000
@@ -1806,6 +1806,8 @@ return_command (char *retval_exp, int fr
the cast fail, this call throws an error. */
if (thisfun != NULL)
return_type = TYPE_TARGET_TYPE (SYMBOL_TYPE (thisfun));
+ else
+ return_type = value_type (return_value);
if (return_type == NULL)
return_type = builtin_type (get_frame_arch (thisframe))->builtin_int;
CHECK_TYPEDEF (return_type);
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ gdb/testsuite/gdb.base/return-nodebug.c 12 Feb 2009 09:24:18 -0000
@@ -0,0 +1,40 @@
+/* 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/>. */
+
+#include <stdio.h>
+
+static TYPE
+func (void)
+{
+ return (TYPE) -1;
+}
+
+static void
+marker (void)
+{
+}
+
+int
+main (void)
+{
+ printf ("result=" FORMAT "\n", CAST func ());
+
+ /* Cannot `next' with no debug info. */
+ marker ();
+
+ return 0;
+}
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ gdb/testsuite/gdb.base/return-nodebug.exp 12 Feb 2009 09:24:18 -0000
@@ -0,0 +1,55 @@
+# Copyright (C) 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/>.
+
+proc do_test {type} {
+ set typenospace [string map {{ } -} $type]
+
+ global pf_prefix
+ set old_prefix $pf_prefix
+ lappend pf_prefix "$typenospace:"
+
+ if {[runto "func"]} {
+ # Test return from a function with no debug info (symbol; still it may
+ # have a minimal-symbol) if it does not crash.
+ # Cast of the result to the proper width must be done explicitely.
+ gdb_test "return ($type) -1" "#0 .* main \\(.*" \
+ "return from function with no debug info" \
+ "Make selected stack frame return now\\? \\(y or n\\) " "y"
+
+ # And if it returned the full width of the result.
+ gdb_test "adv marker" "\r\nresult=-1\r\n.* in marker \\(.*" \
+ "full width of the returned result"
+ }
+
+ set pf_prefix $old_prefix
+}
+
+foreach case {{{char} %d (int)} \
+ {{short} %d (int)} \
+ {{int} %d} \
+ {{long} %ld} \
+ {{long long} %lld}} {
+ set type [lindex $case 0]
+ set format [lindex $case 1]
+ set cast [lindex $case 2]
+
+ set typeesc [string map {{ } {\ }} $type]
+ set typenospace [string map {{ } -} $type]
+
+ if {[prepare_for_testing return-nodebug.exp "return-nodebug-$typenospace" "return-nodebug.c" \
+ [list "additional_flags=-DFORMAT=\"$format\" -DTYPE=$typeesc -DCAST=$cast"]] == 0} {
+ do_test $type
+ }
+}