#!/usr/bin/perl -s
#
# This file is part of Cygwin.
#
# This software is a copyrighted work licensed under the terms of the
# Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
# details.
#
my $tls = shift;
my $tls_out = shift;
my $tgt = shift;
# FIXME?  This method obviously requires a 64 bit OS to build tlsoffsets64.h
# Another method which doesn't requires to run an executable would be to
# generate assembler code accessing the various struct members and analyzing
# it, but that's arguably a lot more effort.
my $tgt_opt = $tgt eq 'x86_64' ? '-m64' : '-m32';
open TLS, '<', $tls or die "$0: couldn't open tls file \"$tls\" - $!\n";
my $struct = '';
my @fields = ();
my $def = '';
$tls = join('', <TLS>);
$tls =~ s/\A.*\n#pragma once\n//os;
$tls =~ s/\n[^\n]*gentls_offsets[^\n]*\n(.+)\Z/$1/os;
my $pre = $`;
substr($tls, 0, length($pre)) = '';
$pre .= "\n//*/";
$tls =~ s%/\*\s*gentls_offsets.*?/\*\s*gentls_offsets\s*\*/%%ogs;
foreach ($tls =~ /^.*\n/mg) {
    /^}|\s*(?:typedef|const)/o and do {
	$def .= $_ ;
	next;
    };
    $def .= $_ if $struct;
    if (!s/;.*$//o) {
	if (!$struct && /^\s*(?:struct|class)\s*([a-z_0-9]+)/o) {
	    $def .= $_;
	    $struct = $1
	}
	next;
    }
    s/(?:\[[^\]]*\]|struct|class)//o;
    s/^\s+\S+\s+//o;
    s/[\*\s()]+//go;
    for my $f (split(/,/)) {
	push(@fields, $f);
    }
}
close TLS;
open TMP, '>', "/tmp/$$.cc" or die "$0: couldn't open temporary index file \"/tmp/$$.c\" - $!\n";
print TMP <<EOF;
#define __INSIDE_CYGWIN__
#ifndef __x86_64__
#define __attribute__(X)
#endif
#define __reg1
#define __reg2
#define __reg3
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <windows.h>
$pre
$def
int
main(int argc, char **argv)
{
  $struct *foo;
# define foo_beg ((char *) foo)
# define offset(f) ((unsigned)((int) (((char *) &(foo->f)) - foo_beg) - CYGTLS_PADSIZE))
# define poffset(f) ((unsigned)(((char *) &(foo->f)) - ((char *) foo)))
EOF
    print TMP 'puts ("//;# autogenerated:  Do not edit.\n");', "\n\n";
    print TMP "printf (\"//; \$tls::start_offset = -%d;\\n\", CYGTLS_PADSIZE);\n";
    for my $f (@fields) {
	print TMP '  printf ("//; $tls::', $f, ' = %d;\n", ', "offset($f));\n";
	print TMP '  printf ("//; $tls::p', $f, ' = %d;\n", ', "poffset($f));\n";
    }
    print TMP '  puts ("//; __DATA__\n");', "\n";
    for my $f (@fields) {
	print TMP '  printf ("#define tls_', $f, ' (%d)\n", ', "offset($f));\n";
	print TMP '  printf ("#define tls_p', $f, ' (%d)\n", ', "poffset($f));\n";
    }

    print TMP <<EOF;

  exit (0);
}
EOF
close TMP;
my @avoid_headers = qw'-D_XMMINTRIN_H_INCLUDED -D_ADXINTRIN_H_INCLUDED -D_EMMINTRIN_H_INCLUDED -D_X86INTRIN_H_INCLUDED';
my @cmd = (@ARGV, @avoid_headers, '-o', "/tmp/$$-1.cc", '-E', "/tmp/$$.cc");
$ENV{CCWRAP_VERBOSE}=1;
system @cmd;
system 'g++', "$tgt_opt", '-o', "/tmp/$$.a.out", "/tmp/$$-1.cc" and
($? == 127 && system 'c++', "$tgt_opt", '-o', "/tmp/$$.a.out", "/tmp/$$-1.cc") and
die "$0: couldn't generate executable for offset calculation \"/tmp/$$.a.out\" - $!\n";
open TLS_OUT, '>', $tls_out or die "$0: couldn't open tls index file \"$tls_out\" - $!\n";
open OFFS, '-|', "/tmp/$$.a.out" or die "$0: couldn't run \"/tmp/$$.a.out\" - $!\n";
print TLS_OUT <OFFS>;
close OFFS;
close TLS_OUT;
unlink "/tmp/$$.cc", "/tmp/$$-1.cc", "/tmp/$$-1.d", "/tmp/$$.a.out";
exit(0);