[perl5.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

#
# 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;
    }
    return $obj->{iv};
}

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

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

sub B::Stackobj::Padsv::load_double {
    my $obj = shift;
    $obj->write_back;
    runtime("$obj->{nv} = SvNV($obj->{sv});");
    $obj->{flags} |= VALID_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 MB	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 MB	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 MB	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 MB	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
	33
	34	#
	35	# Callback for runtime code generation
	36	#
	37	my $runtime_callback = sub { confess "set_callback not yet called" };
	38	sub set_callback (&) { $runtime_callback = shift }
	39	sub runtime { &$runtime_callback(@_) }
	40
	41	#
	42	# Methods
	43	#
	44
	45	sub write_back { confess "stack object does not implement write_back" }
	46
	47	sub invalidate { shift->{flags} &= ~(VALID_INT \| VALID_DOUBLE) }
	48
	49	sub as_sv {
	50	my $obj = shift;
	51	if (!($obj->{flags} & VALID_SV)) {
	52	$obj->write_back;
	53	$obj->{flags} \|= VALID_SV;
	54	}
	55	return $obj->{sv};
	56	}
	57
	58	sub as_int {
	59	my $obj = shift;
	60	if (!($obj->{flags} & VALID_INT)) {
	61	$obj->load_int;
	62	$obj->{flags} \|= VALID_INT;
	63	}
	64	return $obj->{iv};
	65	}
	66
	67	sub as_double {
	68	my $obj = shift;
	69	if (!($obj->{flags} & VALID_DOUBLE)) {
	70	$obj->load_double;
	71	$obj->{flags} \|= VALID_DOUBLE;
	72	}
	73	return $obj->{nv};
	74	}
	75
	76	sub as_numeric {
	77	my $obj = shift;
	78	return $obj->{type} == T_INT ? $obj->as_int : $obj->as_double;
	79	}
	80
a9b6343a VB	81	sub as_bool {
	82	my $obj=shift;
	83	if ($obj->{flags} & VALID_INT ){
	84	return $obj->{iv};
	85	}
	86	if ($obj->{flags} & VALID_DOUBLE ){
	87	return $obj->{nv};
	88	}
	89	return sprintf("(SvTRUE(%s))", $obj->as_sv) ;
	90	}
73544139	91
a798dbf2 MB	92	#
	93	# Debugging methods
	94	#
	95	sub peek {
	96	my $obj = shift;
	97	my $type = $obj->{type};
	98	my $flags = $obj->{flags};
	99	my @flags;
	100	if ($type == T_UNKNOWN) {
	101	$type = "T_UNKNOWN";
	102	} elsif ($type == T_INT) {
	103	$type = "T_INT";
	104	} elsif ($type == T_DOUBLE) {
	105	$type = "T_DOUBLE";
	106	} else {
	107	$type = "(illegal type $type)";
	108	}
	109	push(@flags, "VALID_INT") if $flags & VALID_INT;
	110	push(@flags, "VALID_DOUBLE") if $flags & VALID_DOUBLE;
	111	push(@flags, "VALID_SV") if $flags & VALID_SV;
	112	push(@flags, "REGISTER") if $flags & REGISTER;
	113	push(@flags, "TEMPORARY") if $flags & TEMPORARY;
	114	@flags = ("none") unless @flags;
	115	return sprintf("%s type=$type flags=%s sv=$obj->{sv}",
	116	class($obj), join("\|", @flags));
	117	}
	118
	119	sub minipeek {
	120	my $obj = shift;
	121	my $type = $obj->{type};
	122	my $flags = $obj->{flags};
	123	if ($type == T_INT \|\| $flags & VALID_INT) {
	124	return $obj->{iv};
	125	} elsif ($type == T_DOUBLE \|\| $flags & VALID_DOUBLE) {
	126	return $obj->{nv};
	127	} else {
	128	return $obj->{sv};
	129	}
	130	}
	131
	132	#
	133	# Caller needs to ensure that set_int, set_double,
	134	# set_numeric and set_sv are only invoked on legal lvalues.
	135	#
	136	sub set_int {
	137	my ($obj, $expr) = @_;
	138	runtime("$obj->{iv} = $expr;");
	139	$obj->{flags} &= ~(VALID_SV \| VALID_DOUBLE);
	140	$obj->{flags} \|= VALID_INT;
	141	}
	142
	143	sub set_double {
	144	my ($obj, $expr) = @_;
	145	runtime("$obj->{nv} = $expr;");
	146	$obj->{flags} &= ~(VALID_SV \| VALID_INT);
	147	$obj->{flags} \|= VALID_DOUBLE;
	148	}
	149
	150	sub set_numeric {
	151	my ($obj, $expr) = @_;
	152	if ($obj->{type} == T_INT) {
	153	$obj->set_int($expr);
	154	} else {
	155	$obj->set_double($expr);
156	}
157	}
158
159	sub set_sv {
160	my ($obj, $expr) = @_;
161	runtime("SvSetSV($obj->{sv}, $expr);");
162	$obj->invalidate;
163	$obj->{flags} \|= VALID_SV;
164	}
165
166	#
167	# Stackobj::Padsv
168	#
169
170	@B::Stackobj::Padsv::ISA = 'B::Stackobj';
171	sub B::Stackobj::Padsv::new {
172	my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_;
173	bless {
174	type => $type,
175	flags => VALID_SV \| $extra_flags,
81009501	176	sv => "PL_curpad[$ix]",
a798dbf2 MB	177	iv => "$iname",
	178	nv => "$dname"
	179	}, $class;
	180	}
	181
	182	sub B::Stackobj::Padsv::load_int {
	183	my $obj = shift;
	184	if ($obj->{flags} & VALID_DOUBLE) {
	185	runtime("$obj->{iv} = $obj->{nv};");
	186	} else {
	187	runtime("$obj->{iv} = SvIV($obj->{sv});");
	188	}
	189	$obj->{flags} \|= VALID_INT;
	190	}
	191
	192	sub B::Stackobj::Padsv::load_double {
	193	my $obj = shift;
	194	$obj->write_back;
	195	runtime("$obj->{nv} = SvNV($obj->{sv});");
	196	$obj->{flags} \|= VALID_DOUBLE;
	197	}
	198
	199	sub B::Stackobj::Padsv::write_back {
	200	my $obj = shift;
	201	my $flags = $obj->{flags};
	202	return if $flags & VALID_SV;
	203	if ($flags & VALID_INT) {
	204	runtime("sv_setiv($obj->{sv}, $obj->{iv});");
	205	} elsif ($flags & VALID_DOUBLE) {
	206	runtime("sv_setnv($obj->{sv}, $obj->{nv});");
	207	} else {
	208	confess "write_back failed for lexical @{[$obj->peek]}\n";
	209	}
	210	$obj->{flags} \|= VALID_SV;
	211	}
	212
	213	#
	214	# Stackobj::Const
	215	#
	216
	217	@B::Stackobj::Const::ISA = 'B::Stackobj';
	218	sub B::Stackobj::Const::new {
	219	my ($class, $sv) = @_;
	220	my $obj = bless {
	221	flags => 0,
	222	sv => $sv # holds the SV object until write_back happens
	223	}, $class;
73544139 NIS	224	if ( ref($sv) eq "B::SPECIAL" ){
	225	$obj->{type}= T_SPECIAL;
	226	}else{
	227	my $svflags = $sv->FLAGS;
	228	if ($svflags & SVf_IOK) {
	229	$obj->{flags} = VALID_INT\|VALID_DOUBLE;
	230	$obj->{type} = T_INT;
	231	$obj->{nv} = $obj->{iv} = $sv->IV;
	232	} elsif ($svflags & SVf_NOK) {
	233	$obj->{flags} = VALID_INT\|VALID_DOUBLE;
	234	$obj->{type} = T_DOUBLE;
	235	$obj->{iv} = $obj->{nv} = $sv->NV;
	236	} else {
	237	$obj->{type} = T_UNKNOWN;
	238	}
a798dbf2 MB	239	}
	240	return $obj;
	241	}
	242
	243	sub B::Stackobj::Const::write_back {
	244	my $obj = shift;
	245	return if $obj->{flags} & VALID_SV;
	246	# Save the SV object and replace $obj->{sv} by its C source code name
	247	$obj->{sv} = $obj->{sv}->save;
	248	$obj->{flags} \|= VALID_SV\|VALID_INT\|VALID_DOUBLE;
	249	}
	250
	251	sub B::Stackobj::Const::load_int {
	252	my $obj = shift;
	253	$obj->{iv} = int($obj->{sv}->PV);
	254	$obj->{flags} \|= VALID_INT;
	255	}
	256
	257	sub B::Stackobj::Const::load_double {
	258	my $obj = shift;
	259	$obj->{nv} = $obj->{sv}->PV + 0.0;
	260	$obj->{flags} \|= VALID_DOUBLE;
	261	}
	262
	263	sub B::Stackobj::Const::invalidate {}
	264
	265	#
	266	# Stackobj::Bool
	267	#
	268
	269	@B::Stackobj::Bool::ISA = 'B::Stackobj';
	270	sub B::Stackobj::Bool::new {
	271	my ($class, $preg) = @_;
	272	my $obj = bless {
	273	type => T_INT,
	274	flags => VALID_INT\|VALID_DOUBLE,
	275	iv => $$preg,
	276	nv => $$preg,
	277	preg => $preg # this holds our ref to the pseudo-reg
	278	}, $class;
	279	return $obj;
	280	}
	281
	282	sub B::Stackobj::Bool::write_back {
	283	my $obj = shift;
	284	return if $obj->{flags} & VALID_SV;
81009501	285	$obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)";
a798dbf2 MB	286	$obj->{flags} \|= VALID_SV;
	287	}
	288
	289	# XXX Might want to handle as_double/set_double/load_double?
	290
	291	sub B::Stackobj::Bool::invalidate {}
	292
	293	1;
7f20e9dd GS	294
	295	__END__
	296
	297	=head1 NAME
	298
	299	B::Stackobj - Helper module for CC backend
	300
	301	=head1 SYNOPSIS
	302
	303	use B::Stackobj;
	304
	305	=head1 DESCRIPTION
	306
	307	See F<ext/B/README>.
	308
	309	=head1 AUTHOR
	310
	311	Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>
	312
	313	=cut