This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: Prevent crashes using $arg0
On Tue, Feb 07, 2006 at 10:38:28PM +0200, Eli Zaretskii wrote:
> Is it possible to have $arg0 behave outside user-defined functions as
> any other convenience variable? That is, can we have this response
> instead:
>
> (gdb) if 1 == 1
> >print $arg0
> >end
> $1 = void
> (gdb)
>
> ? If this is not too hard, it's cleaner, since it doesn't reserve the
> names of these variables globally.
Good idea.
> [Time passes...] Actually, I'm quite sure we should behave like I
> suggested, since we already do that without the if clause:
>
> (gdb) print $arg0
> $1 = void
> (gdb)
And let's test that too.
Does this look better? Tested x86_64-pc-linux-gnu.
--
Daniel Jacobowitz
CodeSourcery
2006-02-20 Daniel Jacobowitz <dan@codesourcery.com>
* cli/cli-script.c (insert_args): Handle NULL user_args.
2006-02-20 Daniel Jacobowitz <dan@codesourcery.com>
* gdb.base/commands.exp (stray_arg0_test): New test.
Index: cli/cli-script.c
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-script.c,v
retrieving revision 1.32
diff -u -p -r1.32 cli-script.c
--- cli/cli-script.c 17 Dec 2005 22:40:17 -0000 1.32
+++ cli/cli-script.c 20 Feb 2006 16:00:50 -0000
@@ -1,8 +1,8 @@
/* GDB CLI command scripting.
Copyright (c) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
- 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005 Free
- Software Foundation, Inc.
+ 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006
+ Free Software Foundation, Inc.
This file is part of GDB.
@@ -590,6 +590,11 @@ insert_args (char *line)
char *p, *save_line, *new_line;
unsigned len, i;
+ /* If we are not in a user-defined function, treat $argc, $arg0, et
+ cetera as normal convenience variables. */
+ if (user_args == NULL)
+ return xstrdup (line);
+
/* First we need to know how much memory to allocate for the new line. */
save_line = line;
len = 0;
Index: testsuite/gdb.base/commands.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.base/commands.exp,v
retrieving revision 1.14
diff -u -p -r1.14 commands.exp
--- testsuite/gdb.base/commands.exp 7 Mar 2005 21:36:16 -0000 1.14
+++ testsuite/gdb.base/commands.exp 20 Feb 2006 16:00:50 -0000
@@ -1,5 +1,5 @@
# Copyright 1988, 1990, 1991, 1992, 1994, 1995, 1997, 1998, 1999, 2000,
-# 2001, 2002, 2003 Free Software Foundation, Inc.
+# 2001, 2002, 2003, 2005, 2006 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
@@ -563,6 +563,26 @@ proc temporary_breakpoint_commands {} {
timeout { fail "(timeout) run factorial until temporary breakpoint" }
}
}
+
+# Test that GDB can handle $arg0 outside of user functions without
+# crashing.
+proc stray_arg0_test { } {
+ gdb_test "print \$arg0" \
+ "\\\$\[0-9\]* = void" \
+ "stray_arg0_test #1"
+
+ gdb_test "if 1 == 1\nprint \$arg0\nend" \
+ "\\\$\[0-9\]* = void" \
+ "stray_arg0_test #2"
+
+ gdb_test "print \$arg0 = 1" \
+ "\\\$\[0-9\]* = 1" \
+ "stray_arg0_test #3"
+
+ gdb_test "print \$arg0" \
+ "\\\$\[0-9\]* = 1" \
+ "stray_arg0_test #4"
+}
gdbvar_simple_if_test
gdbvar_simple_while_test
@@ -579,3 +599,4 @@ test_command_prompt_position
deprecated_command_test
bp_deleted_in_command_test
temporary_breakpoint_commands
+stray_arg0_test