3 # Copyright (c) 1996 Malcolm Beattie
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.
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)]);
21 # Perl internal constants that I should probably define elsewhere.
22 sub SVf_IOK () { 0x10000 }
23 sub SVf_NOK () { 0x20000 }
26 sub T_UNKNOWN () { 0 }
29 sub T_SPECIAL () { 3 }
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
39 # Callback for runtime code generation
41 my $runtime_callback = sub { confess "set_callback not yet called" };
42 sub set_callback (&) { $runtime_callback = shift }
43 sub runtime { &$runtime_callback(@_) }
49 sub write_back { confess "stack object does not implement write_back" }
51 sub invalidate { shift->{flags} &= ~(VALID_INT | VALID_DOUBLE) }
55 if (!($obj->{flags} & VALID_SV)) {
57 $obj->{flags} |= VALID_SV;
64 if (!($obj->{flags} & VALID_INT)) {
66 $obj->{flags} |= VALID_INT;
73 if (!($obj->{flags} & VALID_DOUBLE)) {
75 $obj->{flags} |= VALID_DOUBLE;
82 return $obj->{type} == T_INT ? $obj->as_int : $obj->as_double;
87 if ($obj->{flags} & VALID_INT ){
90 if ($obj->{flags} & VALID_DOUBLE ){
93 return sprintf("(SvTRUE(%s))", $obj->as_sv) ;
101 my $type = $obj->{type};
102 my $flags = $obj->{flags};
104 if ($type == T_UNKNOWN) {
106 } elsif ($type == T_INT) {
108 } elsif ($type == T_DOUBLE) {
111 $type = "(illegal type $type)";
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));
125 my $type = $obj->{type};
126 my $flags = $obj->{flags};
127 if ($type == T_INT || $flags & VALID_INT) {
129 } elsif ($type == T_DOUBLE || $flags & VALID_DOUBLE) {
137 # Caller needs to ensure that set_int, set_double,
138 # set_numeric and set_sv are only invoked on legal lvalues.
141 my ($obj, $expr) = @_;
142 runtime("$obj->{iv} = $expr;");
143 $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE);
144 $obj->{flags} |= VALID_INT;
148 my ($obj, $expr) = @_;
149 runtime("$obj->{nv} = $expr;");
150 $obj->{flags} &= ~(VALID_SV | VALID_INT);
151 $obj->{flags} |= VALID_DOUBLE;
155 my ($obj, $expr) = @_;
156 if ($obj->{type} == T_INT) {
157 $obj->set_int($expr);
159 $obj->set_double($expr);
164 my ($obj, $expr) = @_;
165 runtime("SvSetSV($obj->{sv}, $expr);");
167 $obj->{flags} |= VALID_SV;
174 @B::Stackobj::Padsv::ISA = 'B::Stackobj';
175 sub B::Stackobj::Padsv::new {
176 my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_;
179 flags => VALID_SV | $extra_flags,
180 sv => "PL_curpad[$ix]",
186 sub B::Stackobj::Padsv::load_int {
188 if ($obj->{flags} & VALID_DOUBLE) {
189 runtime("$obj->{iv} = $obj->{nv};");
191 runtime("$obj->{iv} = SvIV($obj->{sv});");
193 $obj->{flags} |= VALID_INT;
196 sub B::Stackobj::Padsv::load_double {
199 runtime("$obj->{nv} = SvNV($obj->{sv});");
200 $obj->{flags} |= VALID_DOUBLE;
203 sub B::Stackobj::Padsv::write_back {
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}, $obj->{nv});");
212 confess "write_back failed for lexical @{[$obj->peek]}\n";
214 $obj->{flags} |= VALID_SV;
221 @B::Stackobj::Const::ISA = 'B::Stackobj';
222 sub B::Stackobj::Const::new {
223 my ($class, $sv) = @_;
226 sv => $sv # holds the SV object until write_back happens
228 if ( ref($sv) eq "B::SPECIAL" ){
229 $obj->{type}= T_SPECIAL;
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;
241 $obj->{type} = T_UNKNOWN;
247 sub B::Stackobj::Const::write_back {
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;
255 sub B::Stackobj::Const::load_int {
257 $obj->{iv} = int($obj->{sv}->PV);
258 $obj->{flags} |= VALID_INT;
261 sub B::Stackobj::Const::load_double {
263 $obj->{nv} = $obj->{sv}->PV + 0.0;
264 $obj->{flags} |= VALID_DOUBLE;
267 sub B::Stackobj::Const::invalidate {}
273 @B::Stackobj::Bool::ISA = 'B::Stackobj';
274 sub B::Stackobj::Bool::new {
275 my ($class, $preg) = @_;
278 flags => VALID_INT|VALID_DOUBLE,
281 preg => $preg # this holds our ref to the pseudo-reg
286 sub B::Stackobj::Bool::write_back {
288 return if $obj->{flags} & VALID_SV;
289 $obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)";
290 $obj->{flags} |= VALID_SV;
293 # XXX Might want to handle as_double/set_double/load_double?
295 sub B::Stackobj::Bool::invalidate {}
303 B::Stackobj - Helper module for CC backend
315 Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>