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

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Thu, 05 Mar 2009 01:15:08 +0100, Tom Tromey wrote:
> >>>>> "Mark" == Mark Kettenis <mark.kettenis@xs4all.nl> writes:
> 
> Mark> Do we have a way to figure out if such a cast is present in the
> Mark> expression passed as an argument to the return command?
> 
> Yeah, it is not too hard.  It just means having return_command call
> parse_expression directly, then look at the resulting expression.

Attached, check-in approval requested.


Regards,
Jan

gdb/
2009-03-09  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* stack.c (return_command <retval_exp>): New variables retval_expr
	and old_chain.  Inline parse_and_eval to initialize retval_expr.  Check
	RETVAL_EXPR for UNOP_CAST and set RETURN_TYPE to the RETURN_VALUE type
	if RETURN_TYPE is NULL.

gdb/testsuite/
2009-03-09  Jan Kratochvil  <jan.kratochvil@redhat.com>

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

--- gdb/stack.c	6 Mar 2009 18:51:05 -0000	1.186
+++ gdb/stack.c	9 Mar 2009 01:52:55 -0000
@@ -1796,18 +1796,26 @@ return_command (char *retval_exp, int fr
      message.  */
   if (retval_exp)
     {
+      struct expression *retval_expr = parse_expression (retval_exp);
+      struct cleanup *old_chain = make_cleanup (xfree, retval_expr);
       struct type *return_type = NULL;
 
       /* Compute the return value.  Should the computation fail, this
          call throws an error.  */
-      return_value = parse_and_eval (retval_exp);
+      return_value = evaluate_expression (retval_expr);
 
       /* Cast return value to the return type of the function.  Should
          the cast fail, this call throws an error.  */
       if (thisfun != NULL)
 	return_type = TYPE_TARGET_TYPE (SYMBOL_TYPE (thisfun));
       if (return_type == NULL)
-	return_type = builtin_type (get_frame_arch (thisframe))->builtin_int;
+      	{
+	  if (retval_expr->elts[0].opcode != UNOP_CAST)
+	    error (_("Selected stack frame (with no associated function) "
+		     "requires an explicit cast of the value to return"));
+	  return_type = value_type (return_value);
+	}
+      do_cleanups (old_chain);
       CHECK_TYPEDEF (return_type);
       return_value = value_cast (return_type, return_value);
 
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ gdb/testsuite/gdb.base/return-nodebug.c	9 Mar 2009 01:52:55 -0000
@@ -0,0 +1,49 @@
+/* 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
+init (void)
+{
+  return 0;
+}
+
+static TYPE
+func (void)
+{
+  return 31;
+}
+
+static void
+marker (void)
+{
+}
+
+int
+main (void)
+{
+  /* Preinitialize registers to 0 to avoid false PASS by leftover garbage.  */
+  init ();
+
+  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	9 Mar 2009 01:52:55 -0000
@@ -0,0 +1,60 @@
+# 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.
+
+    	gdb_test "return -1" \
+		 "Selected stack frame \\(with no associated function\\) requires an explicit cast of the value to return" \
+		 "return from function with no debug info without a cast"
+
+	# 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 with a cast"	\
+		 "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 {{{signed 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
+    }
+}