package Configure::Step;

use strict;
use vars qw($description @args);
use Parrot::Configure::Step ':auto';

$description="Determining if your C compiler is actually gcc...";

@args=qw(miniparrot);

sub runstep {
  my ($miniparrot) = @_;

  my %gnuc;

  cc_gen("config/auto/gcc/test_c.in");
  cc_build();
  %gnuc=eval cc_run() or die "Can't run the test program: $!";
  cc_clean();

  my($gccversion, $warns, $cc_warn);
  $cc_warn=Configure::Data->get('cc_warn');
  
  unless (exists $gnuc{__GNUC__}) {
    return;
  }
  my $major = $gnuc{__GNUC__};
  my $minor = $gnuc{__GNUC_MINOR__};
  unless (defined $major) {
    return;
  }
  if ($major =~ tr/0-9//c) {
    undef $major; # Don't use it
  }
  if (defined $minor and $minor =~ tr/0-9//c) {
    undef $minor; # Don't use it
  }
  if (defined $major) {
    $gccversion = $major;
    $gccversion .= ".$minor" if defined $minor;
  }

  if ($gccversion) {
    # If using gcc, crank up its warnings as much as possible and make it
    # behave  ansi-ish.
    # Here's an attempt at a list of nasty things we can use for a given
    # version of gcc. The earliest documentation I currently have access to is
    # for 2.95, so I don't know what version everything came in at. If it turns
    # out that you're using 2.7.2 and -Wfoo isn't recognised there, move it up
    # into the next version becone (2.8)

    # Don't use -ansi -pedantic.  It makes it much harder to compile
    # using the system headers, which may well be tuned to a
    # non-strict environment -- especially since we are using perl5
    # compilation flags determined in a non-strict environment.
    # An example is Solaris 8.

    my @opt_and_vers = 
        (0 => "-Wall -Wstrict-prototypes -Wmissing-prototypes -Winline -Wshadow -Wpointer-arith -Wcast-qual -Wcast-align -Wwrite-strings -Waggregate-return -Winline -W -Wno-unused",
        # others; ones we might like marked with ?
        # ? -Wundef for undefined idenfiers in #if
        # ? -Wbad-function-cast
        #   Warn whenever a function call is cast to a non-matching type
        # ? -Wmissing-declarations
        #   Warn if a global function is defined without a previous declaration
        # -Wmissing-noreturn
        # ? -Wredundant-decls
        #    Warn if anything is declared more than once in the same scope,
        # ? -Wnested-externs
        #    Warn if an `extern' declaration is encountered within an function.
        # -Wlong-long
        # Ha. this is the default! with -pedantic.
        # -Wno-long-long for the nicest bit of C99
         2.7 => "",
         2.8 => "-Wsign-compare",
         2.95 => "",
         3.0 => "-Wformat-nonliteral -Wformat-security -Wpacked -Wpadded -Wdisabled-optimization",
        # -Wsequence-point is part of -Wall
        # -Wfloat-equal may not be what we want
        # We shouldn't be using __packed__, but I doubt -Wpacked will harm us
        # -Wpadded may prove interesting, or even noisy.
        # -Wunreachable-code might be useful in a non debugging version
    );
    $warns = "";
    while (my ($vers, $opt) = splice @opt_and_vers, 0, 2) {
      last if $vers > $gccversion;
      next unless $opt; # Ignore blank lines
      $warns .= " $opt";
    }
  }

  if (defined $miniparrot && $gccversion) {
      # make the compiler act as ANSIish as possible, and avoid enabling
      # support for GCC-specific features.

      Configure::Data->set(
          cc_warn    => "-ansi -pedantic",
          gccversion => undef
      );

      return;
  }

  Configure::Data->set(
    cc_warn    => "$warns $cc_warn",
    gccversion => $gccversion
  );
}

1;
