Subversion Repositories openrisc_2011-10-31

/* Common VxWorks target definitions for GNU compiler.

   Copyright (C) 2007, 2008

   Free Software Foundation, Inc.

   Contributed by CodeSourcery, Inc.

This file is part of GCC.

GCC 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, or (at your option) any later

version.

GCC 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 GCC; see the file COPYING3.  If not see

<http://www.gnu.org/licenses/>.  */

#include "config.h"

#include "system.h"

#include "coretypes.h"

#include "target.h"

#include "toplev.h"

#include "output.h"

#include "tm.h"

#include "tree.h"

/* Like default_named_section_asm_out_constructor, except that even

   constructors with DEFAULT_INIT_PRIORITY must go in a numbered

   section on VxWorks.  The VxWorks runtime uses a clever trick to get

   the sentinel entry (-1) inserted at the beginning of the .ctors

   segment.  This trick will not work if we ever generate any entries

   in plain .ctors sections; we must always use .ctors.PRIORITY.  */

void

vxworks_asm_out_constructor (rtx symbol, int priority)

{

  section *sec;

  sec = get_cdtor_priority_section (priority,

                                    /*constructor_p=*/true);

  assemble_addr_to_section (symbol, sec);

}

/* See comment for vxworks_asm_out_constructor.  */

void

vxworks_asm_out_destructor (rtx symbol, int priority)

{

  section *sec;

  sec = get_cdtor_priority_section (priority,

                                    /*constructor_p=*/false);

  assemble_addr_to_section (symbol, sec);

}

/* Return the list of FIELD_DECLs that make up an emulated TLS

   variable's control object.  TYPE is the structure these are fields

   of and *NAME will be filled in with the structure tag that should

   be used.  */

static tree

vxworks_emutls_var_fields (tree type, tree *name)

{

  tree field, next_field;

  *name = get_identifier ("__tls_var");

  field = build_decl (FIELD_DECL, get_identifier ("size"),

                      unsigned_type_node);

  DECL_CONTEXT (field) = type;

  next_field = field;

  field = build_decl (FIELD_DECL, get_identifier ("module_id"),

                      unsigned_type_node);

  DECL_CONTEXT (field) = type;

  TREE_CHAIN (field) = next_field;

  next_field = field;

  field = build_decl (FIELD_DECL, get_identifier ("offset"),

                      unsigned_type_node);

  DECL_CONTEXT (field) = type;

  TREE_CHAIN (field) = next_field;

  return field;

}

/* Return the CONSTRUCTOR to initialize an emulated TLS control

   object.  VAR is the control object.  DECL is the TLS object itself

   and TMPL_ADDR is the address (an ADDR_EXPR) of the initializer for

   that object.  */

static tree

vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)

{

  VEC(constructor_elt,gc) *v = VEC_alloc (constructor_elt, gc, 3);

  constructor_elt *elt;

  tree type = TREE_TYPE (var);

  tree field = TYPE_FIELDS (type);

  elt = VEC_quick_push (constructor_elt, v, NULL);

  elt->index = field;

  elt->value = fold_convert (TREE_TYPE (field), tmpl_addr);

  elt = VEC_quick_push (constructor_elt, v, NULL);

  field = TREE_CHAIN (field);

  elt->index = field;

  elt->value = build_int_cst (TREE_TYPE (field), 0);

  elt = VEC_quick_push (constructor_elt, v, NULL);

  field = TREE_CHAIN (field);

  elt->index = field;

  elt->value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));

  return build_constructor (type, v);

}

/* Do VxWorks-specific parts of OVERRIDE_OPTIONS.  */

void

vxworks_override_options (void)

{

  /* We don't support __thread via target hooks.  */

  targetm.have_tls = false;

  targetm.emutls.get_address = "__builtin___tls_lookup";

  targetm.emutls.register_common = NULL;

  targetm.emutls.var_section = ".tls_vars";

  targetm.emutls.tmpl_section = ".tls_data";

  targetm.emutls.var_prefix = "__tls__";

  targetm.emutls.tmpl_prefix = "";

  targetm.emutls.var_fields = vxworks_emutls_var_fields;

  targetm.emutls.var_init = vxworks_emutls_var_init;

  targetm.emutls.var_align_fixed = true;

  targetm.emutls.debug_form_tls_address = true;

  /* We can use .ctors/.dtors sections only in RTP mode.  */

  targetm.have_ctors_dtors = TARGET_VXWORKS_RTP;

  /* PIC is only supported for RTPs.  */

  if (flag_pic && !TARGET_VXWORKS_RTP)

    error ("PIC is only supported for RTPs");

}