[p5sagit/p5-mst-13.2.git] / ext / B / B / Stackobj.pm

#      Stackobj.pm
#
#      Copyright (c) 1996 Malcolm Beattie
#
#      You may distribute under the terms of either the GNU General Public
#      License or the Artistic License, as specified in the README file.
#
package B::Stackobj;  
use Exporter ();
@ISA = qw(Exporter);
@EXPORT_OK = qw(set_callback T_UNKNOWN T_DOUBLE T_INT
		VALID_INT VALID_DOUBLE VALID_SV REGISTER TEMPORARY);
%EXPORT_TAGS = (types => [qw(T_UNKNOWN T_DOUBLE T_INT)],
		flags => [qw(VALID_INT VALID_DOUBLE VALID_SV
			     REGISTER TEMPORARY)]);

use Carp qw(confess);
use strict;
use B qw(class SVf_IOK SVf_NOK);

# Types
sub T_UNKNOWN () { 0 }
sub T_DOUBLE ()  { 1 }
sub T_INT ()     { 2 }
sub T_SPECIAL () { 3 }

# Flags
sub VALID_INT ()	{ 0x01 }
sub VALID_DOUBLE ()	{ 0x02 }
sub VALID_SV ()		{ 0x04 }
sub REGISTER ()		{ 0x08 } # no implicit write-back when calling subs
sub TEMPORARY ()	{ 0x10 } # no implicit write-back needed at all
sub SAVE_INT () 	{ 0x20 } #if int part needs to be saved at all
sub SAVE_DOUBLE () 	{ 0x40 } #if double part needs to be saved at all


#
# Callback for runtime code generation
#
my $runtime_callback = sub { confess "set_callback not yet called" };
sub set_callback (&) { $runtime_callback = shift }
sub runtime { &$runtime_callback(@_) }

#
# Methods
#

sub write_back { confess "stack object does not implement write_back" }

sub invalidate { shift->{flags} &= ~(VALID_INT | VALID_DOUBLE) }

sub as_sv {
    my $obj = shift;
    if (!($obj->{flags} & VALID_SV)) {
	$obj->write_back;
	$obj->{flags} |= VALID_SV;
    }
    return $obj->{sv};
}

sub as_int {
    my $obj = shift;
    if (!($obj->{flags} & VALID_INT)) {
	$obj->load_int;
	$obj->{flags} |= VALID_INT|SAVE_INT;
    }
    return $obj->{iv};
}

sub as_double {
    my $obj = shift;
    if (!($obj->{flags} & VALID_DOUBLE)) {
	$obj->load_double;
	$obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE;
    }
    return $obj->{nv};
}

sub as_numeric {
    my $obj = shift;
    return $obj->{type} == T_INT ? $obj->as_int : $obj->as_double;
}

sub as_bool {
	my $obj=shift;
	if ($obj->{flags} & VALID_INT ){
		return $obj->{iv}; 
	}
	if ($obj->{flags} & VALID_DOUBLE ){
		return $obj->{nv}; 
	}
	return sprintf("(SvTRUE(%s))", $obj->as_sv) ;
}

#
# Debugging methods
#
sub peek {
    my $obj = shift;
    my $type = $obj->{type};
    my $flags = $obj->{flags};
    my @flags;
    if ($type == T_UNKNOWN) {
	$type = "T_UNKNOWN";
    } elsif ($type == T_INT) {
	$type = "T_INT";
    } elsif ($type == T_DOUBLE) {
	$type = "T_DOUBLE";
    } else {
	$type = "(illegal type $type)";
    }
    push(@flags, "VALID_INT") if $flags & VALID_INT;
    push(@flags, "VALID_DOUBLE") if $flags & VALID_DOUBLE;
    push(@flags, "VALID_SV") if $flags & VALID_SV;
    push(@flags, "REGISTER") if $flags & REGISTER;
    push(@flags, "TEMPORARY") if $flags & TEMPORARY;
    @flags = ("none") unless @flags;
    return sprintf("%s type=$type flags=%s sv=$obj->{sv}",
		   class($obj), join("|", @flags));
}

sub minipeek {
    my $obj = shift;
    my $type = $obj->{type};
    my $flags = $obj->{flags};
    if ($type == T_INT || $flags & VALID_INT) {
	return $obj->{iv};
    } elsif ($type == T_DOUBLE || $flags & VALID_DOUBLE) {
	return $obj->{nv};
    } else {
	return $obj->{sv};
    }
}

#
# Caller needs to ensure that set_int, set_double,
# set_numeric and set_sv are only invoked on legal lvalues.
#
sub set_int {
    my ($obj, $expr) = @_;
    runtime("$obj->{iv} = $expr;");
    $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE);
    $obj->{flags} |= VALID_INT|SAVE_INT;
}

sub set_double {
    my ($obj, $expr) = @_;
    runtime("$obj->{nv} = $expr;");
    $obj->{flags} &= ~(VALID_SV | VALID_INT);
    $obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE;
}

sub set_numeric {
    my ($obj, $expr) = @_;
    if ($obj->{type} == T_INT) {
	$obj->set_int($expr);
    } else {
	$obj->set_double($expr);
    }
}

sub set_sv {
    my ($obj, $expr) = @_;
    runtime("SvSetSV($obj->{sv}, $expr);");
    $obj->invalidate;
    $obj->{flags} |= VALID_SV;
}

#
# Stackobj::Padsv
#

@B::Stackobj::Padsv::ISA = 'B::Stackobj';
sub B::Stackobj::Padsv::new {
    my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_;
    $extra_flags |= SAVE_INT if $extra_flags & VALID_INT;
    $extra_flags |= SAVE_DOUBLE if $extra_flags & VALID_DOUBLE;
    bless {
	type => $type,
	flags => VALID_SV | $extra_flags,
	sv => "PL_curpad[$ix]",
	iv => "$iname",
	nv => "$dname"
    }, $class;
}

sub B::Stackobj::Padsv::load_int {
    my $obj = shift;
    if ($obj->{flags} & VALID_DOUBLE) {
	runtime("$obj->{iv} = $obj->{nv};");
    } else {
	runtime("$obj->{iv} = SvIV($obj->{sv});");
    }
    $obj->{flags} |= VALID_INT|SAVE_INT;
}

sub B::Stackobj::Padsv::load_double {
    my $obj = shift;
    $obj->write_back;
    runtime("$obj->{nv} = SvNV($obj->{sv});");
    $obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE;
}
sub B::Stackobj::Padsv::save_int {
    my $obj = shift;
    return $obj->{flags} & SAVE_INT;
}

sub B::Stackobj::Padsv::save_double {
    my $obj = shift;
    return $obj->{flags} & SAVE_DOUBLE;
}

sub B::Stackobj::Padsv::write_back {
    my $obj = shift;
    my $flags = $obj->{flags};
    return if $flags & VALID_SV;
    if ($flags & VALID_INT) {
	runtime("sv_setiv($obj->{sv}, $obj->{iv});");
    } elsif ($flags & VALID_DOUBLE) {
	runtime("sv_setnv($obj->{sv}, $obj->{nv});");
    } else {
	confess "write_back failed for lexical @{[$obj->peek]}\n";
    }
    $obj->{flags} |= VALID_SV;
}

#
# Stackobj::Const
#

@B::Stackobj::Const::ISA = 'B::Stackobj';
sub B::Stackobj::Const::new {
    my ($class, $sv) = @_;
    my $obj = bless {
	flags => 0,
	sv => $sv    # holds the SV object until write_back happens
    }, $class;
    if ( ref($sv) eq  "B::SPECIAL" ){
	$obj->{type}= T_SPECIAL;	
    }else{
    	my $svflags = $sv->FLAGS;
    	if ($svflags & SVf_IOK) {
		$obj->{flags} = VALID_INT|VALID_DOUBLE;
		$obj->{type} = T_INT;
		$obj->{nv} = $obj->{iv} = $sv->IV;
    	} elsif ($svflags & SVf_NOK) {
		$obj->{flags} = VALID_INT|VALID_DOUBLE;
		$obj->{type} = T_DOUBLE;
		$obj->{iv} = $obj->{nv} = $sv->NV;
    	} else {
		$obj->{type} = T_UNKNOWN;
    	}
    }
    return $obj;
}

sub B::Stackobj::Const::write_back {
    my $obj = shift;
    return if $obj->{flags} & VALID_SV;
    # Save the SV object and replace $obj->{sv} by its C source code name
    $obj->{sv} = $obj->{sv}->save;
    $obj->{flags} |= VALID_SV|VALID_INT|VALID_DOUBLE;
}

sub B::Stackobj::Const::load_int {
    my $obj = shift;
    $obj->{iv} = int($obj->{sv}->PV);
    $obj->{flags} |= VALID_INT;
}

sub B::Stackobj::Const::load_double {
    my $obj = shift;
    $obj->{nv} = $obj->{sv}->PV + 0.0;
    $obj->{flags} |= VALID_DOUBLE;
}

sub B::Stackobj::Const::invalidate {}

#
# Stackobj::Bool
#

@B::Stackobj::Bool::ISA = 'B::Stackobj';
sub B::Stackobj::Bool::new {
    my ($class, $preg) = @_;
    my $obj = bless {
	type => T_INT,
	flags => VALID_INT|VALID_DOUBLE,
	iv => $$preg,
	nv => $$preg,
	preg => $preg		# this holds our ref to the pseudo-reg
    }, $class;
    return $obj;
}

sub B::Stackobj::Bool::write_back {
    my $obj = shift;
    return if $obj->{flags} & VALID_SV;
    $obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)";
    $obj->{flags} |= VALID_SV;
}

# XXX Might want to handle as_double/set_double/load_double?

sub B::Stackobj::Bool::invalidate {}

1;

__END__

=head1 NAME

B::Stackobj - Helper module for CC backend

=head1 SYNOPSIS

	use B::Stackobj;

=head1 DESCRIPTION

See F<ext/B/README>.

=head1 AUTHOR

Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>

=cut
Commit	Line	Data
a798dbf2	1	# Stackobj.pm
	2	#
	3	# Copyright (c) 1996 Malcolm Beattie
	4	#
	5	# You may distribute under the terms of either the GNU General Public
	6	# License or the Artistic License, as specified in the README file.
	7	#
4c1f658f	8	package B::Stackobj;
a798dbf2	9	use Exporter ();
	10	@ISA = qw(Exporter);
	11	@EXPORT_OK = qw(set_callback T_UNKNOWN T_DOUBLE T_INT
	12	VALID_INT VALID_DOUBLE VALID_SV REGISTER TEMPORARY);
	13	%EXPORT_TAGS = (types => [qw(T_UNKNOWN T_DOUBLE T_INT)],
	14	flags => [qw(VALID_INT VALID_DOUBLE VALID_SV
	15	REGISTER TEMPORARY)]);
	16
	17	use Carp qw(confess);
	18	use strict;
4c1f658f	19	use B qw(class SVf_IOK SVf_NOK);
a798dbf2	20
	21	# Types
	22	sub T_UNKNOWN () { 0 }
	23	sub T_DOUBLE () { 1 }
	24	sub T_INT () { 2 }
73544139	25	sub T_SPECIAL () { 3 }
a798dbf2	26
	27	# Flags
	28	sub VALID_INT () { 0x01 }
	29	sub VALID_DOUBLE () { 0x02 }
	30	sub VALID_SV () { 0x04 }
	31	sub REGISTER () { 0x08 } # no implicit write-back when calling subs
	32	sub TEMPORARY () { 0x10 } # no implicit write-back needed at all
8bac7e00	33	sub SAVE_INT () { 0x20 } #if int part needs to be saved at all
	34	sub SAVE_DOUBLE () { 0x40 } #if double part needs to be saved at all
	35
a798dbf2	36
	37	#
	38	# Callback for runtime code generation
	39	#
	40	my $runtime_callback = sub { confess "set_callback not yet called" };
	41	sub set_callback (&) { $runtime_callback = shift }
	42	sub runtime { &$runtime_callback(@_) }
	43
	44	#
	45	# Methods
	46	#
	47
	48	sub write_back { confess "stack object does not implement write_back" }
	49
	50	sub invalidate { shift->{flags} &= ~(VALID_INT \| VALID_DOUBLE) }
	51
	52	sub as_sv {
	53	my $obj = shift;
	54	if (!($obj->{flags} & VALID_SV)) {
	55	$obj->write_back;
	56	$obj->{flags} \|= VALID_SV;
	57	}
	58	return $obj->{sv};
	59	}
	60
	61	sub as_int {
	62	my $obj = shift;
	63	if (!($obj->{flags} & VALID_INT)) {
	64	$obj->load_int;
8bac7e00	65	$obj->{flags} \|= VALID_INT\|SAVE_INT;
a798dbf2	66	}
	67	return $obj->{iv};
	68	}
	69
	70	sub as_double {
	71	my $obj = shift;
	72	if (!($obj->{flags} & VALID_DOUBLE)) {
	73	$obj->load_double;
8bac7e00	74	$obj->{flags} \|= VALID_DOUBLE\|SAVE_DOUBLE;
a798dbf2	75	}
	76	return $obj->{nv};
	77	}
	78
	79	sub as_numeric {
	80	my $obj = shift;
	81	return $obj->{type} == T_INT ? $obj->as_int : $obj->as_double;
	82	}
	83
a9b6343a	84	sub as_bool {
	85	my $obj=shift;
	86	if ($obj->{flags} & VALID_INT ){
	87	return $obj->{iv};
	88	}
	89	if ($obj->{flags} & VALID_DOUBLE ){
	90	return $obj->{nv};
	91	}
	92	return sprintf("(SvTRUE(%s))", $obj->as_sv) ;
	93	}
73544139	94
a798dbf2	95	#
	96	# Debugging methods
	97	#
	98	sub peek {
	99	my $obj = shift;
	100	my $type = $obj->{type};
	101	my $flags = $obj->{flags};
	102	my @flags;
	103	if ($type == T_UNKNOWN) {
	104	$type = "T_UNKNOWN";
	105	} elsif ($type == T_INT) {
	106	$type = "T_INT";
	107	} elsif ($type == T_DOUBLE) {
	108	$type = "T_DOUBLE";
	109	} else {
	110	$type = "(illegal type $type)";
	111	}
	112	push(@flags, "VALID_INT") if $flags & VALID_INT;
	113	push(@flags, "VALID_DOUBLE") if $flags & VALID_DOUBLE;
	114	push(@flags, "VALID_SV") if $flags & VALID_SV;
	115	push(@flags, "REGISTER") if $flags & REGISTER;
	116	push(@flags, "TEMPORARY") if $flags & TEMPORARY;
	117	@flags = ("none") unless @flags;
	118	return sprintf("%s type=$type flags=%s sv=$obj->{sv}",
	119	class($obj), join("\|", @flags));
	120	}
	121
	122	sub minipeek {
	123	my $obj = shift;
	124	my $type = $obj->{type};
	125	my $flags = $obj->{flags};
	126	if ($type == T_INT \|\| $flags & VALID_INT) {
	127	return $obj->{iv};
	128	} elsif ($type == T_DOUBLE \|\| $flags & VALID_DOUBLE) {
	129	return $obj->{nv};
	130	} else {
	131	return $obj->{sv};
	132	}
	133	}
	134
	135	#
	136	# Caller needs to ensure that set_int, set_double,
	137	# set_numeric and set_sv are only invoked on legal lvalues.
	138	#
	139	sub set_int {
	140	my ($obj, $expr) = @_;
	141	runtime("$obj->{iv} = $expr;");
	142	$obj->{flags} &= ~(VALID_SV \| VALID_DOUBLE);
8bac7e00	143	$obj->{flags} \|= VALID_INT\|SAVE_INT;
a798dbf2	144	}
	145
	146	sub set_double {
	147	my ($obj, $expr) = @_;
	148	runtime("$obj->{nv} = $expr;");
	149	$obj->{flags} &= ~(VALID_SV \| VALID_INT);
8bac7e00	150	$obj->{flags} \|= VALID_DOUBLE\|SAVE_DOUBLE;
a798dbf2	151	}
	152
	153	sub set_numeric {
	154	my ($obj, $expr) = @_;
	155	if ($obj->{type} == T_INT) {
	156	$obj->set_int($expr);
	157	} else {
	158	$obj->set_double($expr);
	159	}
	160	}
	161
	162	sub set_sv {
	163	my ($obj, $expr) = @_;
	164	runtime("SvSetSV($obj->{sv}, $expr);");
	165	$obj->invalidate;
	166	$obj->{flags} \|= VALID_SV;
	167	}
	168
	169	#
	170	# Stackobj::Padsv
	171	#
	172
	173	@B::Stackobj::Padsv::ISA = 'B::Stackobj';
	174	sub B::Stackobj::Padsv::new {
	175	my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_;
8bac7e00	176	$extra_flags \|= SAVE_INT if $extra_flags & VALID_INT;
8bac7e00	177	$extra_flags \|= SAVE_DOUBLE if $extra_flags & VALID_DOUBLE;
a798dbf2	178	bless {
	179	type => $type,
	180	flags => VALID_SV \| $extra_flags,
81009501	181	sv => "PL_curpad[$ix]",
a798dbf2	182	iv => "$iname",
	183	nv => "$dname"
	184	}, $class;
	185	}
	186
	187	sub B::Stackobj::Padsv::load_int {
	188	my $obj = shift;
	189	if ($obj->{flags} & VALID_DOUBLE) {
	190	runtime("$obj->{iv} = $obj->{nv};");
	191	} else {
	192	runtime("$obj->{iv} = SvIV($obj->{sv});");
	193	}
8bac7e00	194	$obj->{flags} \|= VALID_INT\|SAVE_INT;
a798dbf2	195	}
	196
	197	sub B::Stackobj::Padsv::load_double {
	198	my $obj = shift;
	199	$obj->write_back;
	200	runtime("$obj->{nv} = SvNV($obj->{sv});");
8bac7e00	201	$obj->{flags} \|= VALID_DOUBLE\|SAVE_DOUBLE;
	202	}
	203	sub B::Stackobj::Padsv::save_int {
	204	my $obj = shift;
	205	return $obj->{flags} & SAVE_INT;
	206	}
	207
	208	sub B::Stackobj::Padsv::save_double {
	209	my $obj = shift;
	210	return $obj->{flags} & SAVE_DOUBLE;
a798dbf2	211	}
	212
	213	sub B::Stackobj::Padsv::write_back {
	214	my $obj = shift;
	215	my $flags = $obj->{flags};
	216	return if $flags & VALID_SV;
	217	if ($flags & VALID_INT) {
	218	runtime("sv_setiv($obj->{sv}, $obj->{iv});");
	219	} elsif ($flags & VALID_DOUBLE) {
	220	runtime("sv_setnv($obj->{sv}, $obj->{nv});");
	221	} else {
	222	confess "write_back failed for lexical @{[$obj->peek]}\n";
	223	}
	224	$obj->{flags} \|= VALID_SV;
	225	}
	226
	227	#
	228	# Stackobj::Const
	229	#
	230
	231	@B::Stackobj::Const::ISA = 'B::Stackobj';
	232	sub B::Stackobj::Const::new {
	233	my ($class, $sv) = @_;
	234	my $obj = bless {
	235	flags => 0,
	236	sv => $sv # holds the SV object until write_back happens
	237	}, $class;
73544139	238	if ( ref($sv) eq "B::SPECIAL" ){
	239	$obj->{type}= T_SPECIAL;
	240	}else{
	241	my $svflags = $sv->FLAGS;
	242	if ($svflags & SVf_IOK) {
	243	$obj->{flags} = VALID_INT\|VALID_DOUBLE;
	244	$obj->{type} = T_INT;
	245	$obj->{nv} = $obj->{iv} = $sv->IV;
	246	} elsif ($svflags & SVf_NOK) {
	247	$obj->{flags} = VALID_INT\|VALID_DOUBLE;
	248	$obj->{type} = T_DOUBLE;
	249	$obj->{iv} = $obj->{nv} = $sv->NV;
	250	} else {
	251	$obj->{type} = T_UNKNOWN;
	252	}
a798dbf2	253	}
	254	return $obj;
	255	}
	256
	257	sub B::Stackobj::Const::write_back {
	258	my $obj = shift;
	259	return if $obj->{flags} & VALID_SV;
	260	# Save the SV object and replace $obj->{sv} by its C source code name
	261	$obj->{sv} = $obj->{sv}->save;
	262	$obj->{flags} \|= VALID_SV\|VALID_INT\|VALID_DOUBLE;
	263	}
	264
	265	sub B::Stackobj::Const::load_int {
	266	my $obj = shift;
	267	$obj->{iv} = int($obj->{sv}->PV);
	268	$obj->{flags} \|= VALID_INT;
	269	}
	270
	271	sub B::Stackobj::Const::load_double {
	272	my $obj = shift;
	273	$obj->{nv} = $obj->{sv}->PV + 0.0;
	274	$obj->{flags} \|= VALID_DOUBLE;
	275	}
	276
	277	sub B::Stackobj::Const::invalidate {}
	278
	279	#
	280	# Stackobj::Bool
	281	#
	282
	283	@B::Stackobj::Bool::ISA = 'B::Stackobj';
	284	sub B::Stackobj::Bool::new {
	285	my ($class, $preg) = @_;
	286	my $obj = bless {
	287	type => T_INT,
	288	flags => VALID_INT\|VALID_DOUBLE,
	289	iv => $$preg,
	290	nv => $$preg,
	291	preg => $preg # this holds our ref to the pseudo-reg
	292	}, $class;
	293	return $obj;
	294	}
	295
	296	sub B::Stackobj::Bool::write_back {
	297	my $obj = shift;
	298	return if $obj->{flags} & VALID_SV;
81009501	299	$obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)";
a798dbf2	300	$obj->{flags} \|= VALID_SV;
	301	}
	302
	303	# XXX Might want to handle as_double/set_double/load_double?
	304
	305	sub B::Stackobj::Bool::invalidate {}
	306
	307	1;
7f20e9dd	308
	309	__END__
	310
	311	=head1 NAME
	312
	313	B::Stackobj - Helper module for CC backend
	314
	315	=head1 SYNOPSIS
	316
	317	use B::Stackobj;
	318
	319	=head1 DESCRIPTION
	320
	321	See F<ext/B/README>.
	322
	323	=head1 AUTHOR
	324
	325	Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>
	326
	327	=cut