/* Additional functions for the GCC driver on Darwin native.
   Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc.
   Contributed by Apple Computer 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/>.  */

#ifndef CROSS_DIRECTORY_STRUCTURE
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "gcc.h"
#include <sys/sysctl.h>
#include "xregex.h"

#ifndef SWITCH_TAKES_ARG
#define SWITCH_TAKES_ARG(CHAR) DEFAULT_SWITCH_TAKES_ARG(CHAR)
#endif

#ifndef WORD_SWITCH_TAKES_ARG
#define WORD_SWITCH_TAKES_ARG(STR) DEFAULT_WORD_SWITCH_TAKES_ARG (STR)
#endif

/* When running on a Darwin system and using that system's headers and
   libraries, default the -mmacosx-version-min flag to be the version
   of the system on which the compiler is running.  */

void
darwin_default_min_version (int * argc_p, char *** argv_p)
{
  const int argc = *argc_p;
  char ** const argv = *argv_p;
  int i;
  char osversion[32];
  size_t osversion_len = sizeof (osversion) - 1;
  static int osversion_name[2] = { CTL_KERN, KERN_OSRELEASE };
  char * version_p;
  char * version_pend;
  int major_vers;
  char minor_vers[6];
  static char new_flag[sizeof ("-mmacosx-version-min=10.0.0") + 6];

  /* If the command-line is empty, just return.  */
  if (argc <= 1)
    return;
  /* Don't do this if the user has specified -b or -V at the start
     of the command-line.  */
  if (argv[1][0] == '-'
      && (argv[1][1] == 'V' ||
	  ((argv[1][1] == 'b') && (NULL != strchr(argv[1] + 2,'-')))))
    return;
  
  /* Don't do this if the user specified -mmacosx-version-min= or
     -mno-macosx-version-min.  */
  for (i = 1; i < argc; i++)
    if (argv[i][0] == '-')
      {
	const char * const p = argv[i];
	if (strncmp (p, "-mno-macosx-version-min", 23) == 0
	    || strncmp (p, "-mmacosx-version-min", 20) == 0)
	  return;
	
	/* It doesn't count if it's an argument to a different switch.  */
	if (p[0] == '-'
	    && ((SWITCH_TAKES_ARG (p[1]) > (p[2] != 0))
		|| WORD_SWITCH_TAKES_ARG (p + 1)))
	  i++;
      }

  /* Retrieve the deployment target from the environment and insert
     it as a flag.  */
  {
    const char * macosx_deployment_target;
    macosx_deployment_target = getenv ("MACOSX_DEPLOYMENT_TARGET");
    if (macosx_deployment_target
	/* Apparently, an empty string for MACOSX_DEPLOYMENT_TARGET means
	   "use the default".  Or, possibly "use 10.1".  We choose
	   to ignore the environment variable, as if it was never set.  */
	&& macosx_deployment_target[0])
      {
	++*argc_p;
	*argv_p = XNEWVEC (char *, *argc_p);
	(*argv_p)[0] = argv[0];
	(*argv_p)[1] = concat ("-mmacosx-version-min=",
			       macosx_deployment_target, NULL);
	memcpy (*argv_p + 2, argv + 1, (argc - 1) * sizeof (char *));
	return;
      }
  }

  /* Determine the version of the running OS.  If we can't, warn user,
     and do nothing.  */
  if (sysctl (osversion_name, ARRAY_SIZE (osversion_name), osversion,
	      &osversion_len, NULL, 0) == -1)
    {
      fprintf (stderr, "sysctl for kern.osversion failed: %s\n",
	       xstrerror (errno));
      return;
    }

  /* Try to parse the first two parts of the OS version number.  Warn
     user and return if it doesn't make sense.  */
  if (! ISDIGIT (osversion[0]))
    goto parse_failed;
  major_vers = osversion[0] - '0';
  version_p = osversion + 1;
  if (ISDIGIT (*version_p))
    major_vers = major_vers * 10 + (*version_p++ - '0');
  if (major_vers > 4 + 9)
    goto parse_failed;
  if (*version_p++ != '.')
    goto parse_failed;
  version_pend = strchr(version_p, '.');
  if (!version_pend)
    goto parse_failed;
  if (! ISDIGIT (*version_p))
    goto parse_failed;
  strncpy(minor_vers, version_p, version_pend - version_p);
  minor_vers[version_pend - version_p] = '\0';
  
  /* The major kernel version number is 4 plus the second OS version
     component.  */
  if (major_vers - 4 <= 4)
    /* On 10.4 and earlier, the old linker is used which does not
       support three-component system versions.  */
    sprintf (new_flag, "-mmacosx-version-min=10.%d", major_vers - 4);
  else
    sprintf (new_flag, "-mmacosx-version-min=10.%d.%s", major_vers - 4,
	     minor_vers);

  /* Add the new flag.  */
  ++*argc_p;
  *argv_p = XNEWVEC (char *, *argc_p);
  (*argv_p)[0] = argv[0];
  (*argv_p)[1] = new_flag;
  memcpy (*argv_p + 2, argv + 1, (argc - 1) * sizeof (char *));
  return;
  
 parse_failed:
  fprintf (stderr, "couldn't understand kern.osversion `%.*s'\n",
	   (int) osversion_len, osversion);
  return;
}

#endif /* CROSS_DIRECTORY_STRUCTURE */