[PATCH] Fix FreeBSD/Alpha structure return handling

[Mark Kettenis <kettenis at wins dot uva dot nl>]

FYI, I checked this in.

Mark


Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>

	* config/alpha/tm-fbsd.h: Update copyright.
	(USE_STRUCT_CONVENTION): Define in terms of
	alphabsd_use_struct_convention.
	* config/alpha/fbsd.mt (TDEPFILES): Add alphafbsd-tdep.c.
	* alphafbsd-tdep.c: New file.

Index: config/alpha/tm-fbsd.h
===================================================================
RCS file: /cvs/src/src/gdb/config/alpha/tm-fbsd.h,v
retrieving revision 1.1
diff -u -p -r1.1 tm-fbsd.h
--- config/alpha/tm-fbsd.h 2000/05/31 20:26:46 1.1
+++ config/alpha/tm-fbsd.h 2001/01/25 18:38:36
@@ -1,5 +1,5 @@
 /* Target-dependent definitions for FreeBSD/Alpha.
-   Copyright (C) 2000 Free Software Foundation, Inc.
+   Copyright 2000, 2001 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -22,6 +22,12 @@
 #define TM_FBSD_H
 
 #include "alpha/tm-alpha.h"
+
+/* FreeBSD uses the old gcc convention for struct returns.  */
+
+#undef USE_STRUCT_CONVENTION
+#define USE_STRUCT_CONVENTION(gcc_p, type) \
+  alphafbsd_use_struct_convention (gcc_p, type)
 
 /* Number of traps that happen between exec'ing the shell to run an
    inferior, and when we finally get to the inferior code.  The
Index: config/alpha/fbsd.mt
===================================================================
RCS file: /cvs/src/src/gdb/config/alpha/fbsd.mt,v
retrieving revision 1.1
diff -u -p -r1.1 fbsd.mt
--- config/alpha/fbsd.mt 2000/05/31 20:26:46 1.1
+++ config/alpha/fbsd.mt 2001/01/25 18:38:36
@@ -1,3 +1,3 @@
 # Target: FreeBSD/Alpha
-TDEPFILES= alpha-tdep.o
+TDEPFILES= alpha-tdep.o alphafbsd-tdep.o
 TM_FILE= tm-fbsd.h
--- /dev/null	Thu Feb 19 16:30:24 1998
+++ alphafbsd-tdep.c	Thu Jan 25 19:27:04 2001
@@ -0,0 +1,53 @@
+/* Target-dependent code for FreeBSD/Alpha.
+   Copyright 2001 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "value.h"
+
+int
+alphafbsd_use_struct_convention (int gcc_p, struct type *type)
+{
+  enum type_code code;
+  int i;
+
+  /* All aggregate types that won't fit in a register must be returned
+     in memory.  */
+  if (TYPE_LENGTH (type) > REGISTER_SIZE)
+    return 1;
+
+  /* The only aggregate types that can be returned in a register are
+     structs and unions.  Arrays must be returned in memory.  */
+  code = TYPE_CODE (type);
+  if (code != TYPE_CODE_STRUCT && code != TYPE_CODE_UNION)
+    return 1;
+
+  /* We need to check if this struct/union is "integer" like.  For
+     this to be true, the offset of each adressable subfield must be
+     zero.  Note that bit fields are not addressable.  */
+  for (i = 0; i < TYPE_NFIELDS (type); i++)
+    {
+      /* If the field bitsize is non-zero, it isn't adressable.  */
+      if (TYPE_FIELD_BITPOS (type, i) != 0
+	  && TYPE_FIELD_BITSIZE (type, i) == 0)
+	return 1;
+    }
+
+  return 0;
+}