/* VMS specific, C compiler specific functions.
   Copyright (C) 2011-2017 Free Software Foundation, Inc.
   Contributed by Tristan Gingold (gingold@adacore.com).

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 "tm.h"
#include "tree.h"
#include "c-family/c-common.h"
#include "c/c-tree.h"
#include "memmodel.h"
#include "tm_p.h"
#include "c-family/c-pragma.h"
#include "toplev.h"
#include "incpath.h"

/* '#pragma __nostandard' is simply ignored.  */

static void
vms_pragma_nostandard (cpp_reader *pfile ATTRIBUTE_UNUSED)
{
  tree x;

  if (pragma_lex (&x) != CPP_EOF)
    warning (OPT_Wpragmas, "junk at end of #pragma __nostandard");
}

/* '#pragma __standard' is simply ignored.  */

static void
vms_pragma_standard (cpp_reader *pfile ATTRIBUTE_UNUSED)
{
  tree x;

  if (pragma_lex (&x) != CPP_EOF)
    warning (OPT_Wpragmas, "junk at end of #pragma __standard");
}

/* Saved member alignment.  */
static int saved_member_alignment;

/* Handle '#pragma member_alignment'.  */

static void
vms_pragma_member_alignment (cpp_reader *pfile ATTRIBUTE_UNUSED)
{
  tree x;
  int tok;
  const char *arg;

  tok = pragma_lex (&x);

  if (tok == CPP_EOF)
    {
      /* Disable packing.  */
      maximum_field_alignment = initial_max_fld_align;
      return;
    }
  if (tok != CPP_NAME)
    {
      warning (OPT_Wpragmas, "malformed '#pragma member_alignment', ignoring");
      return;
    }

  arg = IDENTIFIER_POINTER (x);
  /* Accept '__' prefix.  */
  if (arg[0] == '_' && arg[1] == '_')
    arg += 2;

  if (strcmp (arg, "save") == 0)
    saved_member_alignment = maximum_field_alignment;
  else if (strcmp (arg, "restore") == 0)
    maximum_field_alignment = saved_member_alignment;
  else
    {
      error ("unknown '#pragma member_alignment' name %s", arg);
      return;
    }
  if (pragma_lex (&x) != CPP_EOF)
    {
      error ("malformed '#pragma member_alignment'");
      return;
    }
}

/* Handle '#pragma nomember_alignment'.  */

static void
vms_pragma_nomember_alignment (cpp_reader *pfile ATTRIBUTE_UNUSED)
{
  tree x;
  int tok;

  tok = pragma_lex (&x);
  if (tok == CPP_NAME)
    {
      const char *arg = IDENTIFIER_POINTER (x);

      /* Accept '__' prefix.  */
      if (arg[0] == '_' && arg[1] == '_')
        arg += 2;

      if (strcmp (arg, "byte") == 0)
        maximum_field_alignment = 1 * BITS_PER_UNIT;
      else if (strcmp (arg, "word") == 0)
        maximum_field_alignment = 2 * BITS_PER_UNIT;
      else if (strcmp (arg, "longword") == 0)
        maximum_field_alignment = 4 * BITS_PER_UNIT;
      else if (strcmp (arg, "quadword") == 0)
        maximum_field_alignment = 8 * BITS_PER_UNIT;
      else if (strcmp (arg, "octaword") == 0)
        maximum_field_alignment = 16 * BITS_PER_UNIT;
      else
        {
          error ("unhandled alignment for '#pragma nomember_alignment'");
        }

      tok = pragma_lex (&x);
    }
  else
    {
      /* Enable packing.  */
      maximum_field_alignment = BITS_PER_UNIT;
    }

  if (tok != CPP_EOF)
    {
      error ("garbage at end of '#pragma nomember_alignment'");
      return;
    }
}

/* The 'extern model' for public data.  This drives how the following
   declarations are handled:
   1) extern int name;
   2) int name;
   3) int name = 5;
   See below for the behavior as implemented by the native compiler.
*/

enum extern_model_kind
{
  /* Create one overlaid section per variable.  All the above declarations (1,
      2 and 3) are handled the same way: they create an overlaid section named
      NAME (and initialized only for 3).  No global symbol is created.
      This is the VAX C behavior.  */
  extern_model_common_block,

  /* Like unix: multiple not-initialized declarations are allowed.
     Only one initialized definition (case 3) is allows, but multiple
     uninitialize definition (case 2) are allowed.
     For case 2, this creates both a section named NAME and a global symbol.
     For case 3, this creates a conditional global symbol defenition and a
     conditional section definition.
     This is the traditional UNIX C behavior.  */
  extern_model_relaxed_refdef,

  /* Like -fno-common.  Only one definition (cases 2 and 3) are allowed.
     This is the ANSI-C model.  */
  extern_model_strict_refdef,

  /* Declarations creates symbols without storage.  */
  extern_model_globalvalue
};

/* Current and saved extern model.  */
static enum extern_model_kind current_extern_model;
static enum extern_model_kind saved_extern_model;

/* Partial handling of '#pragma extern_model'.  */

static void
vms_pragma_extern_model (cpp_reader *pfile ATTRIBUTE_UNUSED)
{
  tree x;
  int tok;
  const char *arg;

  tok = pragma_lex (&x);

  if (tok != CPP_NAME)
    {
      warning (OPT_Wpragmas, "malformed '#pragma extern_model', ignoring");
      return;
    }

  arg = IDENTIFIER_POINTER (x);
  /* Accept "__" prefix.  */
  if (arg[0] == '_' && arg[1] == '_')
    arg += 2;

  if (strcmp (arg, "save") == 0)
    saved_extern_model = current_extern_model;
  else if (strcmp (arg, "restore") == 0)
    current_extern_model = saved_extern_model;
  else if (strcmp (arg, "relaxed_refdef") == 0)
    current_extern_model = extern_model_relaxed_refdef;
  else if (strcmp (arg, "strict_refdef") == 0)
    current_extern_model = extern_model_strict_refdef;
  else if (strcmp (arg, "common_block") == 0)
    current_extern_model = extern_model_common_block;
  else if (strcmp (arg, "globalvalue") == 0)
    {
      sorry ("extern model globalvalue");
      return;
    }
  else
    {
      error ("unknown '#pragma extern_model' model '%s'", arg);
      return;
    }
#if 0
  if (pragma_lex (&x) != CPP_EOF)
    {
      permerror (input_location, "junk at end of '#pragma extern_model'");
      return;
    }
#endif
}

/* Ignore '#pragma message'.  */

static void
vms_pragma_message (cpp_reader *pfile ATTRIBUTE_UNUSED)
{
  /* Completly ignored.  */
#if 0
  pedwarn (input_location, OPT_Wpragmas,
           "vms '#pragma __message' is ignored");
#endif
}

/* Handle '#pragma __extern_prefix'  */

static GTY(()) tree saved_extern_prefix;

static void
vms_pragma_extern_prefix (cpp_reader * ARG_UNUSED (dummy))
{
  enum cpp_ttype tok;
  tree x;

  tok = pragma_lex (&x);
  if (tok == CPP_NAME)
    {
      const char *op = IDENTIFIER_POINTER (x);

      if (!strcmp (op, "__save"))
        saved_extern_prefix = pragma_extern_prefix;
      else if (!strcmp (op, "__restore"))
        pragma_extern_prefix = saved_extern_prefix;
      else
        warning (OPT_Wpragmas,
                 "malformed '#pragma __extern_prefix', ignoring");
      return;
    }
  else if (tok != CPP_STRING)
    {
      warning (OPT_Wpragmas,
               "malformed '#pragma __extern_prefix', ignoring");
    }
  else
    {
      /* Note that the length includes the null terminator.  */
      pragma_extern_prefix = (TREE_STRING_LENGTH (x) > 1 ? x : NULL);
    }
}

/* #pragma __pointer_size  */

static machine_mode saved_pointer_mode;

static void
handle_pragma_pointer_size (const char *pragma_name)
{
  enum cpp_ttype tok;
  tree x;

  tok = pragma_lex (&x);
  if (tok == CPP_NAME)
    {
      const char *op = IDENTIFIER_POINTER (x);

      if (!strcmp (op, "__save"))
        saved_pointer_mode = c_default_pointer_mode;
      else if (!strcmp (op, "__restore"))
        c_default_pointer_mode = saved_pointer_mode;
      else if (!strcmp (op, "__short"))
        c_default_pointer_mode = SImode;
      else if (!strcmp (op, "__long"))
        c_default_pointer_mode = DImode;
      else
        error ("malformed %<#pragma %s%>, ignoring", pragma_name);
    }
  else if (tok == CPP_NUMBER)
    {
      int val;

      if (TREE_CODE (x) == INTEGER_CST)
        val = TREE_INT_CST_LOW (x);
      else
        val = -1;

      if (val == 32)
        c_default_pointer_mode = SImode;
      else if (val == 64)
        c_default_pointer_mode = DImode;
      else
        error ("invalid constant in %<#pragma %s%>", pragma_name);
    }
  else
    {
      error ("malformed %<#pragma %s%>, ignoring", pragma_name);
    }
}

static void
vms_pragma_pointer_size (cpp_reader * ARG_UNUSED (dummy))
{
  /* Ignore if no -mpointer-size option.  */
  if (flag_vms_pointer_size == VMS_POINTER_SIZE_NONE)
    return;

  handle_pragma_pointer_size ("pointer_size");
}

static void
vms_pragma_required_pointer_size (cpp_reader * ARG_UNUSED (dummy))
{
  handle_pragma_pointer_size ("required_pointer_size");
}

/* Add vms-specific pragma.  */

void
vms_c_register_pragma (void)
{
  c_register_pragma (NULL, "__nostandard", vms_pragma_nostandard);
  c_register_pragma (NULL, "nostandard", vms_pragma_nostandard);
  c_register_pragma (NULL, "__standard", vms_pragma_standard);
  c_register_pragma (NULL, "standard", vms_pragma_standard);
  c_register_pragma (NULL, "__member_alignment", vms_pragma_member_alignment);
  c_register_pragma (NULL, "member_alignment", vms_pragma_member_alignment);
  c_register_pragma_with_expansion (NULL, "__nomember_alignment",
                                    vms_pragma_nomember_alignment);
  c_register_pragma_with_expansion (NULL, "nomember_alignment",
                                    vms_pragma_nomember_alignment);
  c_register_pragma (NULL, "__pointer_size",
                     vms_pragma_pointer_size);
  c_register_pragma (NULL, "__required_pointer_size",
                     vms_pragma_required_pointer_size);
  c_register_pragma (NULL, "__extern_model", vms_pragma_extern_model);
  c_register_pragma (NULL, "extern_model", vms_pragma_extern_model);
  c_register_pragma (NULL, "__message", vms_pragma_message);
  c_register_pragma (NULL, "__extern_prefix", vms_pragma_extern_prefix);
}

/* Canonicalize the filename (remove directory prefix, force the .h extension),
   and append it to the directory to create the path, but don't
   turn / into // or // into ///; // may be a namespace escape.  */

static char *
vms_construct_include_filename (const char *fname, cpp_dir *dir)
{
  size_t dlen, flen;
  char *path;
  const char *fbasename = lbasename (fname);
  size_t i;

  dlen = dir->len;
  flen = strlen (fbasename) + 2;
  path = XNEWVEC (char, dlen + 1 + flen + 1);
  memcpy (path, dir->name, dlen);
  if (dlen && !IS_DIR_SEPARATOR (path[dlen - 1]))
    path[dlen++] = '/';
  for (i = 0; i < flen; i++)
    if (fbasename[i] == '.')
      break;
    else
      path[dlen + i] = TOLOWER (fbasename[i]);
  path[dlen + i + 0] = '.';
  path[dlen + i + 1] = 'h';
  path[dlen + i + 2] = 0;

  return path;
}

/* Standard modules list.  */
static const char * const vms_std_modules[] = { "rtldef", "starlet_c", NULL };

/* Find include modules in the include path.  */

void
vms_c_register_includes (const char *sysroot,
                         const char *iprefix ATTRIBUTE_UNUSED, int stdinc)
{
  static const char dir_separator_str[] = { DIR_SEPARATOR, 0 };
  struct cpp_dir *dir;

  /* Add on standard include pathes.  */
  if (!stdinc)
    return;

  for (dir = get_added_cpp_dirs (INC_SYSTEM); dir != NULL; dir = dir->next)
    {
      const char * const *lib;
      for (lib = vms_std_modules; *lib != NULL; lib++)
        {
          char *path;
          struct stat st;

          if (sysroot != NULL)
            path = concat (sysroot, dir->name, dir_separator_str, *lib, NULL);
          else
            path = concat (dir->name, dir_separator_str, *lib, NULL);

          if (stat (path, &st) == 0 && S_ISDIR (st.st_mode))
            {
              cpp_dir *p;

              p = XNEW (cpp_dir);
              p->next = NULL;
              p->name = path;
              p->sysp = 1;
              p->construct = vms_construct_include_filename;
              p->user_supplied_p = 0;
              add_cpp_dir_path (p, INC_SYSTEM);
            }
          else
            free (path);
        }
    }
}

void
vms_c_common_override_options (void)
{
  /* Allow variadic functions without parameters (as declared in starlet).  */
  flag_allow_parameterless_variadic_functions = TRUE;

  /* Initialize c_default_pointer_mode.  */
  switch (flag_vms_pointer_size)
    {
    case VMS_POINTER_SIZE_NONE:
      break;
    case VMS_POINTER_SIZE_32:
      c_default_pointer_mode = SImode;
      break;
    case VMS_POINTER_SIZE_64:
      c_default_pointer_mode = DImode;
      break;
    }
}

/* The default value for _CRTL_VER macro.  */

int
vms_c_get_crtl_ver (void)
{
  return VMS_DEFAULT_CRTL_VER;
}

/* The default value for _VMS_VER macro.  */

int
vms_c_get_vms_ver (void)
{
  return VMS_DEFAULT_VMS_VER;
}