Add support for Tilera TILE-Gx processor.

Signed-off-by: Jeff Kenton <[email protected]>

1 files changed, 165 insertions, 0 deletions

diff --git a/backends/tilegx_retval.c b/backends/tilegx_retval.c
new file mode 100644
index 00000000..fd4feef3
--- /dev/null
+++ b/backends/tilegx_retval.c
@@ -0,0 +1,165 @@
+/* Function return value location for Linux/TILE-Gx ABI.
+   Copyright (C) 2012 Tilera Corporation
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * 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
+
+   or both in parallel, as here.
+
+   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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <assert.h>
+#include <dwarf.h>
+
+#define BACKEND tilegx_
+#include "libebl_CPU.h"
+
+
+/* r0.  */
+static const Dwarf_Op loc_intreg[] =
+  {
+    { .atom = DW_OP_reg0 }
+  };
+#define nloc_intreg	1
+
+/* The return value is a structure and is actually stored in stack space
+   passed in a hidden argument by the caller.  But, the compiler
+   helpfully returns the address of that space in r0.  */
+static const Dwarf_Op loc_aggregate[] =
+  {
+    { .atom = DW_OP_breg0, .number = 0 }
+  };
+#define nloc_aggregate 1
+
+int
+tilegx_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 = 8;
+	  else
+	    return -1;
+	}
+      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;
+        }
+
+      /* Small enough structs are passed directly in registers R0 ... R7.  */
+      if (size <= 8)
+	{
+	intreg:
+	  *locp = loc_intreg;
+	  return nloc_intreg;
+	}
+
+      /* Else fall through.  */
+    case DW_TAG_structure_type:
+    case DW_TAG_class_type:
+    case DW_TAG_union_type:
+    aggregate:
+      *locp = loc_aggregate;
+      return nloc_aggregate;
+
+    case DW_TAG_array_type:
+    case DW_TAG_string_type:
+      if (dwarf_aggregate_size (typedie, &size) == 0 && size <= 8)
+	{
+	  if (tag == DW_TAG_array_type)
+	    {
+	      /* Check if it's a character array.  */
+	      attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
+	      typedie = dwarf_formref_die (attr, &die_mem);
+	      tag = dwarf_tag (typedie);
+	      if (tag != DW_TAG_base_type)
+		goto aggregate;
+	      if (dwarf_formudata (dwarf_attr_integrate (typedie,
+							 DW_AT_byte_size,
+							 &attr_mem),
+				   &size) != 0)
+		return -1;
+	      if (size != 1)
+		goto aggregate;
+	    }
+	  goto intreg;
+	}
+      goto aggregate;
+    }
+
+  /* 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;
+}