[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);

# Perl internal constants that I should probably define elsewhere.
sub SVf_IOK () { 0x10000 }
sub SVf_NOK () { 0x20000 }

# 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	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	#
	8	package B::Stackobj;
	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;
	19	use B qw(class);
	20
	21	# Perl internal constants that I should probably define elsewhere.
	22	sub SVf_IOK () { 0x10000 }
	23	sub SVf_NOK () { 0x20000 }
	24
	25	# Types
	26	sub T_UNKNOWN () { 0 }
	27	sub T_DOUBLE () { 1 }
	28	sub T_INT () { 2 }
9c7139f2	29	sub T_SPECIAL () { 3 }
a798dbf2	30
	31	# Flags
	32	sub VALID_INT () { 0x01 }
	33	sub VALID_DOUBLE () { 0x02 }
	34	sub VALID_SV () { 0x04 }
	35	sub REGISTER () { 0x08 } # no implicit write-back when calling subs
	36	sub TEMPORARY () { 0x10 } # no implicit write-back needed at all
	37
	38	#
	39	# Callback for runtime code generation
	40	#
	41	my $runtime_callback = sub { confess "set_callback not yet called" };
	42	sub set_callback (&) { $runtime_callback = shift }
	43	sub runtime { &$runtime_callback(@_) }
	44
	45	#
	46	# Methods
	47	#
	48
	49	sub write_back { confess "stack object does not implement write_back" }
	50
	51	sub invalidate { shift->{flags} &= ~(VALID_INT \| VALID_DOUBLE) }
	52
	53	sub as_sv {
	54	my $obj = shift;
	55	if (!($obj->{flags} & VALID_SV)) {
	56	$obj->write_back;
	57	$obj->{flags} \|= VALID_SV;
	58	}
	59	return $obj->{sv};
	60	}
	61
	62	sub as_int {
	63	my $obj = shift;
	64	if (!($obj->{flags} & VALID_INT)) {
	65	$obj->load_int;
	66	$obj->{flags} \|= VALID_INT;
	67	}
	68	return $obj->{iv};
	69	}
	70
	71	sub as_double {
	72	my $obj = shift;
	73	if (!($obj->{flags} & VALID_DOUBLE)) {
	74	$obj->load_double;
	75	$obj->{flags} \|= VALID_DOUBLE;
	76	}
	77	return $obj->{nv};
	78	}
	79
	80	sub as_numeric {
	81	my $obj = shift;
	82	return $obj->{type} == T_INT ? $obj->as_int : $obj->as_double;
	83	}
	84
ff144d38	85	sub as_bool {
	86	my $obj=shift;
	87	if ($obj->{flags} & VALID_INT ){
	88	return $obj->{iv};
	89	}
	90	if ($obj->{flags} & VALID_DOUBLE ){
	91	return $obj->{nv};
	92	}
	93	return sprintf("(SvTRUE(%s))", $obj->as_sv) ;
	94	}
	95
a798dbf2	96	#
	97	# Debugging methods
	98	#
	99	sub peek {
	100	my $obj = shift;
	101	my $type = $obj->{type};
	102	my $flags = $obj->{flags};
	103	my @flags;
	104	if ($type == T_UNKNOWN) {
	105	$type = "T_UNKNOWN";
	106	} elsif ($type == T_INT) {
	107	$type = "T_INT";
	108	} elsif ($type == T_DOUBLE) {
	109	$type = "T_DOUBLE";
	110	} else {
	111	$type = "(illegal type $type)";
	112	}
	113	push(@flags, "VALID_INT") if $flags & VALID_INT;
	114	push(@flags, "VALID_DOUBLE") if $flags & VALID_DOUBLE;
	115	push(@flags, "VALID_SV") if $flags & VALID_SV;
	116	push(@flags, "REGISTER") if $flags & REGISTER;
	117	push(@flags, "TEMPORARY") if $flags & TEMPORARY;
	118	@flags = ("none") unless @flags;
	119	return sprintf("%s type=$type flags=%s sv=$obj->{sv}",
	120	class($obj), join("\|", @flags));
	121	}
	122
	123	sub minipeek {
	124	my $obj = shift;
	125	my $type = $obj->{type};
	126	my $flags = $obj->{flags};
	127	if ($type == T_INT \|\| $flags & VALID_INT) {
	128	return $obj->{iv};
	129	} elsif ($type == T_DOUBLE \|\| $flags & VALID_DOUBLE) {
	130	return $obj->{nv};
	131	} else {
	132	return $obj->{sv};
	133	}
	134	}
	135
	136	#
	137	# Caller needs to ensure that set_int, set_double,
	138	# set_numeric and set_sv are only invoked on legal lvalues.
	139	#
	140	sub set_int {
	141	my ($obj, $expr) = @_;
	142	runtime("$obj->{iv} = $expr;");
	143	$obj->{flags} &= ~(VALID_SV \| VALID_DOUBLE);
	144	$obj->{flags} \|= VALID_INT;
	145	}
	146
	147	sub set_double {
	148	my ($obj, $expr) = @_;
	149	runtime("$obj->{nv} = $expr;");
	150	$obj->{flags} &= ~(VALID_SV \| VALID_INT);
	151	$obj->{flags} \|= VALID_DOUBLE;
	152	}
	153
	154	sub set_numeric {
	155	my ($obj, $expr) = @_;
	156	if ($obj->{type} == T_INT) {
	157	$obj->set_int($expr);
	158	} else {
	159	$obj->set_double($expr);
160	}
161	}
162
163	sub set_sv {
164	my ($obj, $expr) = @_;
165	runtime("SvSetSV($obj->{sv}, $expr);");
166	$obj->invalidate;
167	$obj->{flags} \|= VALID_SV;
168	}
169
170	#
171	# Stackobj::Padsv
172	#
173
174	@B::Stackobj::Padsv::ISA = 'B::Stackobj';
175	sub B::Stackobj::Padsv::new {
176	my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_;
177	bless {
178	type => $type,
179	flags => VALID_SV \| $extra_flags,
81009501	180	sv => "PL_curpad[$ix]",
a798dbf2	181	iv => "$iname",
	182	nv => "$dname"
	183	}, $class;
	184	}
	185
	186	sub B::Stackobj::Padsv::load_int {
	187	my $obj = shift;
	188	if ($obj->{flags} & VALID_DOUBLE) {
	189	runtime("$obj->{iv} = $obj->{nv};");
	190	} else {
	191	runtime("$obj->{iv} = SvIV($obj->{sv});");
	192	}
	193	$obj->{flags} \|= VALID_INT;
	194	}
	195
	196	sub B::Stackobj::Padsv::load_double {
	197	my $obj = shift;
	198	$obj->write_back;
	199	runtime("$obj->{nv} = SvNV($obj->{sv});");
	200	$obj->{flags} \|= VALID_DOUBLE;
	201	}
	202
	203	sub B::Stackobj::Padsv::write_back {
	204	my $obj = shift;
	205	my $flags = $obj->{flags};
	206	return if $flags & VALID_SV;
	207	if ($flags & VALID_INT) {
	208	runtime("sv_setiv($obj->{sv}, $obj->{iv});");
	209	} elsif ($flags & VALID_DOUBLE) {
	210	runtime("sv_setnv($obj->{sv}, $obj->{nv});");
	211	} else {
	212	confess "write_back failed for lexical @{[$obj->peek]}\n";
	213	}
	214	$obj->{flags} \|= VALID_SV;
	215	}
	216
	217	#
	218	# Stackobj::Const
	219	#
	220
	221	@B::Stackobj::Const::ISA = 'B::Stackobj';
	222	sub B::Stackobj::Const::new {
	223	my ($class, $sv) = @_;
	224	my $obj = bless {
	225	flags => 0,
	226	sv => $sv # holds the SV object until write_back happens
	227	}, $class;
9c7139f2	228	if ( ref($sv) eq "B::SPECIAL" ){
	229	$obj->{type}= T_SPECIAL;
	230	}else{
	231	my $svflags = $sv->FLAGS;
	232	if ($svflags & SVf_IOK) {
	233	$obj->{flags} = VALID_INT\|VALID_DOUBLE;
	234	$obj->{type} = T_INT;
	235	$obj->{nv} = $obj->{iv} = $sv->IV;
	236	} elsif ($svflags & SVf_NOK) {
	237	$obj->{flags} = VALID_INT\|VALID_DOUBLE;
	238	$obj->{type} = T_DOUBLE;
	239	$obj->{iv} = $obj->{nv} = $sv->NV;
	240	} else {
	241	$obj->{type} = T_UNKNOWN;
	242	}
a798dbf2	243	}
	244	return $obj;
	245	}
	246
	247	sub B::Stackobj::Const::write_back {
	248	my $obj = shift;
	249	return if $obj->{flags} & VALID_SV;
	250	# Save the SV object and replace $obj->{sv} by its C source code name
	251	$obj->{sv} = $obj->{sv}->save;
	252	$obj->{flags} \|= VALID_SV\|VALID_INT\|VALID_DOUBLE;
	253	}
	254
	255	sub B::Stackobj::Const::load_int {
	256	my $obj = shift;
	257	$obj->{iv} = int($obj->{sv}->PV);
	258	$obj->{flags} \|= VALID_INT;
	259	}
	260
	261	sub B::Stackobj::Const::load_double {
	262	my $obj = shift;
	263	$obj->{nv} = $obj->{sv}->PV + 0.0;
	264	$obj->{flags} \|= VALID_DOUBLE;
	265	}
	266
	267	sub B::Stackobj::Const::invalidate {}
	268
	269	#
	270	# Stackobj::Bool
	271	#
	272
	273	@B::Stackobj::Bool::ISA = 'B::Stackobj';
	274	sub B::Stackobj::Bool::new {
	275	my ($class, $preg) = @_;
	276	my $obj = bless {
	277	type => T_INT,
	278	flags => VALID_INT\|VALID_DOUBLE,
	279	iv => $$preg,
	280	nv => $$preg,
	281	preg => $preg # this holds our ref to the pseudo-reg
	282	}, $class;
	283	return $obj;
	284	}
	285
	286	sub B::Stackobj::Bool::write_back {
	287	my $obj = shift;
	288	return if $obj->{flags} & VALID_SV;
81009501	289	$obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)";
a798dbf2	290	$obj->{flags} \|= VALID_SV;
	291	}
	292
	293	# XXX Might want to handle as_double/set_double/load_double?
	294
	295	sub B::Stackobj::Bool::invalidate {}
	296
	297	1;
7f20e9dd	298
	299	__END__
	300
	301	=head1 NAME
	302
	303	B::Stackobj - Helper module for CC backend
	304
	305	=head1 SYNOPSIS
	306
	307	use B::Stackobj;
	308
	309	=head1 DESCRIPTION
	310
	311	See F<ext/B/README>.
	312
	313	=head1 AUTHOR
	314
	315	Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>
	316
	317	=cut