gdb/

	* 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/doc/
	* gdb.texinfo (Returning): New description for missing debug info.

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

7 files changed, 191 insertions, 10 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 71a74ea..e5d892c 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2009-03-15  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.
+
 2009-03-14  Pedro Alves  <pedro@codesourcery.com>
 
 	* remote.c (PACKET_qAttached): New.
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 65aa06b..984011a 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,7 +1,11 @@
+2009-03-15  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* gdb.texinfo (Returning): New description for missing debug info.
+
 2009-03-14  Pedro Alves  <pedro@codesourcery.com>
 
 	* gdb.texinfo (Remote Configuration): Document query-attached.
-        (General Query Packets): Document qAttached.
+	(General Query Packets): Document qAttached.
 
 2009-03-05  Pedro Alves  <pedro@codesourcery.com>
 
@@ -26,8 +30,8 @@
 
 2009-02-14  Vladimir Prus  <vladimir@codesourcery.com>
 
-        * observer.texi: Add parameter 'print_frame' to normal_stop
-        observer.
+	* observer.texi: Add parameter 'print_frame' to normal_stop
+	observer.
 
 2009-02-07  Eli Zaretskii  <eliz@gnu.org>
 
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 33bac26..2ec680a 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -12494,6 +12494,53 @@ returned.  In contrast, the @code{finish} command (@pxref{Continuing
 and Stepping, ,Continuing and Stepping}) resumes execution until the
 selected stack frame returns naturally.
 
+@value{GDBN} needs to know how the @var{expression} argument should be set for
+the inferior.  The concrete registers assignment depends on the OS ABI and the
+type being returned by the selected stack frame.  For example it is common for
+OS ABI to return floating point values in FPU registers while integer values in
+CPU registers.  Still some ABIs return even floating point values in CPU
+registers.  Larger integer widths (such as @code{long long int}) also have
+specific placement rules.  @value{GDBN} already knows the OS ABI from its
+current target so it needs to find out also the type being returned to make the
+assignment into the right register(s).
+
+Normally, the selected stack frame has debug info.  @value{GDBN} will always
+use the debug info instead of the implicit type of @var{expression} when the
+debug info is available.  For example, if you type @kbd{return -1}, and the
+function in the current stack frame is declared to return a @code{long long
+int}, @value{GDBN} transparently converts the implicit @code{int} value of -1
+into a @code{long long int}:
+
+@smallexample
+Breakpoint 1, func () at gdb.base/return-nodebug.c:29
+29        return 31;
+(@value{GDBP}) return -1
+Make func return now? (y or n) y
+#0  0x004004f6 in main () at gdb.base/return-nodebug.c:43
+43        printf ("result=%lld\n", func ());
+(@value{GDBP})
+@end smallexample
+
+However, if the selected stack frame does not have a debug info, e.g., if the
+function was compiled without debug info, @value{GDBN} has to find out the type
+to return from user.  Specifying a different type by mistake may set the value
+in different inferior registers than the caller code expects.  For example,
+typing @kbd{return -1} with its implicit type @code{int} would set only a part
+of a @code{long long int} result for a debug info less function (on 32-bit
+architectures).  Therefore the user is required to specify the return type by
+an appropriate cast explicitly:
+
+@smallexample
+Breakpoint 2, 0x0040050b in func ()
+(@value{GDBP}) return -1
+Return value type not available for selected stack frame.
+Please use an explicit cast of the value to return.
+(@value{GDBP}) return (long long int) -1
+Make selected stack frame return now? (y or n) y
+#0  0x00400526 in main ()
+(@value{GDBP})
+@end smallexample
+
 @node Calling
 @section Calling Program Functions
 
diff --git a/gdb/stack.c b/gdb/stack.c
index d0c872e..d0ea3bf 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -1796,18 +1796,27 @@ return_command (char *retval_exp, int from_tty)
      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 (_("Return value type not available for selected "
+		     "stack frame.\n"
+		     "Please use 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);
 
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index b047421..e889d34 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2009-03-15  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* gdb.base/return-nodebug.exp, gdb.base/return-nodebug.c: New.
+
 2009-03-14  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	Fix a racy FAIL.
@@ -9,7 +13,7 @@
 2009-03-13  Vladimir Prus  <vladimir@codesourcery.com>
 
 	* gdb.mi/mi-cli.exp: Adjust for output difference in
-        sync and async modes.
+	sync and async modes.
 
 2009-03-12  Joel Brobecker  <brobecker@adacore.com>
 
@@ -31,19 +35,19 @@
 
 2009-03-12  Vladimir Prus  <vladimir@codesourcery.com>
 
-        * gdb.mi/mi-cli.exp: Remove debug print.
+	* gdb.mi/mi-cli.exp: Remove debug print.
 
 2009-03-12  Vladimir Prus  <vladimir@codesourcery.com>
 
-        * gdb.mi/mi-cli.exp: Verify that CLI commands that run inferior
-        include the token in ^running and frame info in *stopped.
+	* gdb.mi/mi-cli.exp: Verify that CLI commands that run inferior
+	include the token in ^running and frame info in *stopped.
 
 2009-03-05  Paul Pluzhnikov  <ppluzhnikov@google.com>
 
 	* solib-display.exp: New file.
 	* solib-display-main.c: New file.
 	* solib-display-lib.c: New file.
-	
+
 2009-03-05  Pedro Alves  <pedro@codesourcery.com>
 
 	* gdb.arch/i386-permbkpt.S, gdb.arch/i386-permbkpt.exp: New.
diff --git a/gdb/testsuite/gdb.base/return-nodebug.c b/gdb/testsuite/gdb.base/return-nodebug.c
new file mode 100644
index 0000000..e1211b3
--- /dev/null
+++ b/gdb/testsuite/gdb.base/return-nodebug.c
@@ -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;
+}
diff --git a/gdb/testsuite/gdb.base/return-nodebug.exp b/gdb/testsuite/gdb.base/return-nodebug.exp
new file mode 100644
index 0000000..7d43776
--- /dev/null
+++ b/gdb/testsuite/gdb.base/return-nodebug.exp
@@ -0,0 +1,61 @@
+# 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"]} {
+	# Verify that we do not crash when using "return" from a function with
+	# no debugging info.  Such function has no `struct symbol'.  It may
+	# still have an associated `struct minimal_symbol'.
+
+    	gdb_test "return -1" \
+		 "Return value type not available for selected stack frame\\.\r\nPlease use 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
+    }
+}