| Subject: | Adding SWIG support |
Would like SWIG compilation support in added. It is already possible via
Subclassing, but might be better to have this as common code part of the
package. Attached should is what I think is the relevant excerpt from
Device::Cdio that I used.
One little thing I noticed in this endeavor was that for SWIG
compilation it is helpful to turn off some gcc warning messages until
such time SWIG is fixed to not cause gcc to emit them. So I changed the
order of applying user cflags (extra_compiler_flags) to come *after* the
cflags that are picked up as part of the Perl configuration. Another
possibility is to add a new option to allow cflags specified before and
afterwards.
(I am also trying to get some of this in the SWIG documentation.)
| Subject: | Swig-Build.PL |
#!/usr/bin/perl -w
use strict;
use warnings;
use Module::Build;
use ExtUtils::PkgConfig;
use Config;
my $code = <<'EOC';
sub process_swig_files {
my $self = shift;
my $p = $self->{properties};
return unless $p->{swig_source};
my $files_ref = $p->{swig_source};
foreach my $file (@$files_ref) {
$self->process_swig($file->[0], $file->[1]);
}
}
# Check check dependencies for $main_swig_file. These are the
# %includes. If needed, arrange to run swig on $main_swig_file to
# produce a xxx_wrap.c C file.
sub process_swig {
my ($self, $main_swig_file, $deps_ref) = @_;
my ($cf, $p) = ($self->{config}, $self->{properties}); # For convenience
# File name. e.g, perlcdio.swg -> perlcdio_wrap.c
(my $file_base = $main_swig_file) =~ s/\.[^.]+$//;
my $c_file = "${file_base}_wrap.c";
if ($p->{swig_installed}) {
# .swg -> .c
$self->add_to_cleanup($c_file);
# print "+++ c_file: $c_file, file: $main_swig_file ", `pwd`, "\n";
# If any of the swig files that the main swig depends is newer
# then rebuild.
foreach my $depends_on ($main_swig_file, @$deps_ref) {
unless ($self->up_to_date($depends_on, $c_file)) {
$self->compile_swig($main_swig_file, $c_file);
# Only need to build $c_file once no matter how many
# includes there are.
last;
}
}
}
# .c -> .o
my $obj_file = $self->compile_c($c_file);
$self->add_to_cleanup($obj_file);
# The .so files don't go in blib/lib/, they go in blib/arch/auto/.
# Unfortunately we have to pre-compute the whole path.
my $archdir;
{
my @dirs = File::Spec->splitdir($file_base);
$archdir = File::Spec->catdir($self->blib,'arch', @dirs[1..$#dirs]);
}
# .o -> .so
$self->link_c($archdir, $file_base, $obj_file);
}
# Invoke swig with -perl -outdir and other options.
sub compile_swig {
my ($self, $file, $c_file) = @_;
my ($cf, $p) = ($self->{config}, $self->{properties}); # For convenience
# File name, minus the suffix
(my $file_base = $file) =~ s/\.[^.]+$//;
my @swig;
if (defined($p->{swig})) {
@swig = $self->split_like_shell($p->{swig});
} else {
@swig = ('swig');
}
if (defined($p->{swig_flags})) {
@swig_flags = $self->split_like_shell($p->{swig_flags});
} else {
@swig_flags = ();
}
my $blib_lib = File::Spec->catfile($self->blib, 'lib');
# print "+++swig -o $c_file -outdir $blib_lib -perl $file\n";
$self->do_system(@swig, '-o', $c_file, '-outdir', $blib_lib,
'-perl', @swig_flags, $file)
or die "error building $c_file file from '$file'";
return $c_file;
}
# From Base.pm but modified for a SWIG conventions.
# We just pass a $obj_file parameter
# SWIG objects have a get created with _wrap added. For example
# perlcdio.swg produces perlcdio_wrap.c, and perlcdio_wrap.o.
# But the shared object is still perlcdio.so.
# Also we modified the die to report the full file name.
sub link_c {
my ($self, $to, $file_base, $obj_file) = @_;
my ($cf, $p) = ($self->{config}, $self->{properties}); # For convenience
my $lib_file = File::Spec->catfile($to, File::Basename::basename("$file_base.$cf->{dlext}"));
$self->add_to_cleanup($lib_file);
my $objects = $p->{objects} || [];
unless ($self->up_to_date([$obj_file, @$objects], $lib_file)) {
$self->prelink_c($to, $file_base) if $self->need_prelink_c;
my @linker_flags = $self->split_like_shell($p->{extra_linker_flags});
my @lddlflags = $self->split_like_shell($cf->{lddlflags});
my @shrp = $self->split_like_shell($cf->{shrpenv});
my @ld = $self->split_like_shell($cf->{ld});
$self->do_system(@shrp, @ld, @lddlflags, @user_libs, '-o', $lib_file,
$obj_file, @$objects, @linker_flags)
or die "error building $lib_file file from '$obj_file'";
}
return $lib_file;
}
# From Base.pm but modified to put package cflags *after*
# installed c flags so warning-removal will have an effect.
sub compile_c {
my ($self, $file) = @_;
my ($cf, $p) = ($self->{config}, $self->{properties}); # For convenience
# File name, minus the suffix
(my $file_base = $file) =~ s/\.[^.]+$//;
my $obj_file = "$file_base$cf->{obj_ext}";
$self->add_to_cleanup($obj_file);
return $obj_file if $self->up_to_date($file, $obj_file);
my @include_dirs = map {"-I$_"} (@{$p->{include_dirs}},
File::Spec->catdir($cf->{installarchlib}, 'CORE'));
my @extra_compiler_flags = $self->split_like_shell($p->{extra_compiler_flags});
my @cccdlflags = $self->split_like_shell($cf->{cccdlflags});
my @ccflags = $self->split_like_shell($cf->{ccflags});
my @optimize = $self->split_like_shell($cf->{optimize});
# Whoah! There seems to be a bug in gcc 4.1.0 and optimization
# and swig. I'm not sure who's at fault. But for now the simplest
# thing is to turn off all optimization. For the kinds of things that
# SWIG does - do conversions between parameters and transfers calls
# I doubt optimization makes much of a difference. But if it does,
# it can be added back via @extra_compiler_flags.
my @flags = (@include_dirs, @cccdlflags, '-c', @ccflags,
@extra_compiler_flags, );
my @cc = $self->split_like_shell($cf->{cc});
$self->do_system(@cc, @flags, '-o', $obj_file, $file)
or die "error building $cf->{obj_ext} file from '$file'";
return $obj_file;
}
EOC
sub try_compile {
my ($c, %args) = @_;
my $ok = 0;
my $tmp = "tmp$$";
local(*TMPC);
my $obj_ext = $Config{obj_ext} || ".o";
unlink("$tmp.c", "$tmp$obj_ext");
if (open(TMPC, ">", "$tmp.c")) {
print TMPC $c;
close(TMPC);
my $cccmd = $args{cccmd};
my $errornull;
my $ccflags = $Config{'ccflags'};
$ccflags .= " $args{ccflags}" if $args{ccflags};
if ($args{silent} ) {
$errornull = "2>/dev/null" unless defined $errornull;
} else {
$errornull = '';
}
$cccmd = "$Config{'cc'} -o $tmp $ccflags $tmp.c $errornull"
unless defined $cccmd;
printf "cccmd = $cccmd\n" if $args{verbose};
my $res = system($cccmd);
$ok = defined($res) && $res == 0;
if ( !$ok ) {
my $errno = $? >> 8;
local $! = $errno;
print "
*** The test compile of '$tmp.c' failed: status $?
*** (the status means: errno = $errno or '$!')
*** DO NOT PANIC: this just means that *some* you may get some innocuous
*** compiler warnings.
";
}
unlink("$tmp.c");
}
return $ok;
}
sub try_cflags ($) {
my ($ccflags) = @_;
my $c_prog = "int main () { return 0; }\n";
print "Checking if $Config{cc} supports \"$ccflags\"...";
my $result = try_compile($c_prog, ccflags=>$ccflags);
if ($result) {
print "yes\n";
return " $ccflags";
}
print "no\n";
return '';
}
# ...
print "Checking for SWIG...";
my @swig_version = `swig -version 2>&1`;
my $swig_installed = 0;
if ($?) {
my $errno = $? >> 8;
print "
*** I don't see SWIG installed. I'll use the SWIG-generated file
*** that comes with the distribution. If you want SWIG, get it
*** from http://www.swig.org
";
print "*** Output was:
@swig_version
" if @swig_version;
} else {
$swig_installed = 1;
print "ok\n";
}
my $ccflags = $pkgcfg{cflags};
## Swig produces a number of GCC warnings. Turn them off if we can.
$ccflags .= try_cflags("-Wno-strict-aliasing");
$ccflags .= try_cflags("-Wno-unused-function");
$ccflags .= try_cflags("-Wno-unused-value");
$ccflags .= try_cflags("-Wno-unused-function");
$ccflags .= try_cflags("-Wno-unused-variable");
my $ldflags = $pkgcfg{libs};
my $swig_flags='';
if ('cygwin' eq $Config{osname} &&
$Config{shrpenv} =~ m{\Aenv LD_RUN_PATH=(.*)\Z} ) {
$ldflags .= " -L$1 -lperl";
# Should we check the 32-ness?
$swig_flags = '-DNEED_LONG';
} elsif ('darwin' eq $Config{osname}) {
$ldflags .= " -bundle -flat_namespace";
}
my $class = Module::Build->subclass( code => $code );
my $builder = $class->new(
module_name => 'Your::Module',
add_to_cleanup => [ 'Your-Module-*', 'tmp*' ],
dist_abstract => 'Description of your module',
dist_author => 'Your Name <you@cpan.org>',
dist_version_from => 'lib/Your/Module.pm',
extra_linker_flags => $ldflags,
extra_compiler_flags=> $ccflags,
swig_flags => $swig_flags,
swig_installed => $swig_installed,
license => 'perl',
requires => {
'Test::More' => 0,
'version' => 0,
},
swig_source => [ ['main-swig-module.swg',
['include1.swg', 'include2.swg']] ],
);
$builder->add_build_element('swig');
$builder->create_build_script();