[PATCH 5/5] Return value location support for SuperH.

[Matt Fleming <matt at console-pimps dot org>]

---
 backends/Makefile.am |    2 +-
 backends/sh_init.c   |    1 +
 backends/sh_retval.c |  138 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+), 1 deletions(-)
 create mode 100644 backends/sh_retval.c

diff --git a/backends/Makefile.am b/backends/Makefile.am
index 28ea745..3ce448a 100644
--- a/backends/Makefile.am
+++ b/backends/Makefile.am
@@ -52,7 +52,7 @@ cpu_i386 = ../libcpu/libcpu_i386.a
 libebl_i386_pic_a_SOURCES = $(i386_SRCS)
 am_libebl_i386_pic_a_OBJECTS = $(i386_SRCS:.c=.os)
 
-sh_SRCS = sh_init.c sh_symbol.c sh_corenote.c sh_regs.c
+sh_SRCS = sh_init.c sh_symbol.c sh_corenote.c sh_regs.c sh_retval.c
 libebl_sh_pic_a_SOURCES = $(sh_SRCS)
 am_libebl_sh_pic_a_OBJECTS = $(sh_SRCS:.c=.os)
 
diff --git a/backends/sh_init.c b/backends/sh_init.c
index 686467b..7b36e7a 100644
--- a/backends/sh_init.c
+++ b/backends/sh_init.c
@@ -55,6 +55,7 @@ sh_init (elf, machine, eh, ehlen)
   HOOK (eh, machine_flag_check);
   HOOK (eh, core_note);
   HOOK (eh, register_info);
+  HOOK (eh, return_value_location);
 
   return MODVERSION;
 }
diff --git a/backends/sh_retval.c b/backends/sh_retval.c
new file mode 100644
index 0000000..07769a3
--- /dev/null
+++ b/backends/sh_retval.c
@@ -0,0 +1,138 @@
+/* Function return value location for Linux/SH ABI.
+   Copyright (C) 2010 Matt Fleming <matt@console-pimps.org>
+   This file is part of Red Hat elfutils.
+
+   Red Hat elfutils 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; version 2 of the License.
+
+   Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
+
+   Red Hat elfutils is an included package of the Open Invention Network.
+   An included package of the Open Invention Network is a package for which
+   Open Invention Network licensees cross-license their patents.  No patent
+   license is granted, either expressly or impliedly, by designation as an
+   included package.  Should you wish to participate in the Open Invention
+   Network licensing program, please visit www.openinventionnetwork.com
+   <http://www.openinventionnetwork.com>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <assert.h>
+#include <dwarf.h>
+
+#define BACKEND sh_
+#include "libebl_CPU.h"
+
+
+/* This is the SVR4 ELF ABI convention, but AIX and Linux do not use it.  */
+#define SVR4_STRUCT_RETURN 0
+
+
+/* r0, or pair r0, r1.  */
+static const Dwarf_Op loc_intreg[] =
+  {
+    { .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 4 },
+    { .atom = DW_OP_reg1 }, { .atom = DW_OP_piece, .number = 4 },
+  };
+#define nloc_intreg	1
+#define nloc_intregpair	4
+
+/* fr0 or fr1.  */
+static const Dwarf_Op loc_fpreg[] =
+  {
+    { .atom = DW_OP_reg25 }, { .atom = DW_OP_piece, .number = 4 },
+    { .atom = DW_OP_reg26 }, { .atom = DW_OP_piece, .number = 4 },
+  };
+#define nloc_fpreg	1
+#define nloc_fpregpair	2
+
+int
+sh_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
+{
+  /* Start with the function's type, and get the DW_AT_type attribute,
+     which is the type of the return value.  */
+
+  Dwarf_Attribute attr_mem;
+  Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type,
+						&attr_mem);
+  if (attr == NULL)
+    /* The function has no return value, like a `void' function in C.  */
+    return 0;
+
+  Dwarf_Die die_mem;
+  Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
+  int tag = dwarf_tag (typedie);
+
+  /* Follow typedefs and qualifiers to get to the actual type.  */
+  while (tag == DW_TAG_typedef
+	 || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type
+	 || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type)
+    {
+      attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
+      typedie = dwarf_formref_die (attr, &die_mem);
+      tag = dwarf_tag (typedie);
+    }
+
+  Dwarf_Word size;
+  switch (tag)
+    {
+    case -1:
+      return -1;
+
+    case DW_TAG_subrange_type:
+      if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
+	{
+	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
+	  typedie = dwarf_formref_die (attr, &die_mem);
+	  tag = dwarf_tag (typedie);
+	}
+      /* Fall through.  */
+
+    case DW_TAG_base_type:
+    case DW_TAG_enumeration_type:
+    case DW_TAG_pointer_type:
+    case DW_TAG_ptr_to_member_type:
+      if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
+						 &attr_mem), &size) != 0)
+	{
+	  if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
+	    size = 4;
+	  else
+	    return -1;
+	}
+      if (size <= 8)
+	{
+	  if (tag == DW_TAG_base_type)
+	    {
+	      Dwarf_Word encoding;
+	      if (dwarf_formudata (dwarf_attr_integrate (typedie,
+							 DW_AT_encoding,
+							 &attr_mem),
+				   &encoding) != 0)
+		return -1;
+	      if (encoding == DW_ATE_float)
+		{
+		  *locp = loc_fpreg;
+		  return size <= 4 ? nloc_fpreg : nloc_fpregpair;
+		}
+	    }
+	  *locp = loc_intreg;
+	  return size <= 4 ? nloc_intreg : nloc_intregpair;
+	}
+    }
+
+  /* XXX We don't have a good way to return specific errors from ebl calls.
+     This value means we do not understand the type, but it is well-formed
+     DWARF and might be valid.  */
+  return -2;
+}
-- 
1.7.0.2