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 }
31 sub VALID_INT () { 0x01 }
32 sub VALID_DOUBLE () { 0x02 }
33 sub VALID_SV () { 0x04 }
34 sub REGISTER () { 0x08 } # no implicit write-back when calling subs
35 sub TEMPORARY () { 0x10 } # no implicit write-back needed at all
38 # Callback for runtime code generation
40 my $runtime_callback = sub { confess "set_callback not yet called" };
41 sub set_callback (&) { $runtime_callback = shift }
42 sub runtime { &$runtime_callback(@_) }
48 sub write_back { confess "stack object does not implement write_back" }
50 sub invalidate { shift->{flags} &= ~(VALID_INT | VALID_DOUBLE) }
54 if (!($obj->{flags} & VALID_SV)) {
56 $obj->{flags} |= VALID_SV;
63 if (!($obj->{flags} & VALID_INT)) {
65 $obj->{flags} |= VALID_INT;
72 if (!($obj->{flags} & VALID_DOUBLE)) {
74 $obj->{flags} |= VALID_DOUBLE;
81 return $obj->{type} == T_INT ? $obj->as_int : $obj->as_double;
86 if ($obj->{flags} & VALID_INT ){
89 if ($obj->{flags} & VALID_DOUBLE ){
92 return sprintf("(SvTRUE(%s))", $obj->as_sv) ;
99 my $type = $obj->{type};
100 my $flags = $obj->{flags};
102 if ($type == T_UNKNOWN) {
104 } elsif ($type == T_INT) {
106 } elsif ($type == T_DOUBLE) {
109 $type = "(illegal type $type)";
111 push(@flags, "VALID_INT") if $flags & VALID_INT;
112 push(@flags, "VALID_DOUBLE") if $flags & VALID_DOUBLE;
113 push(@flags, "VALID_SV") if $flags & VALID_SV;
114 push(@flags, "REGISTER") if $flags & REGISTER;
115 push(@flags, "TEMPORARY") if $flags & TEMPORARY;
116 @flags = ("none") unless @flags;
117 return sprintf("%s type=$type flags=%s sv=$obj->{sv}",
118 class($obj), join("|", @flags));
123 my $type = $obj->{type};
124 my $flags = $obj->{flags};
125 if ($type == T_INT || $flags & VALID_INT) {
127 } elsif ($type == T_DOUBLE || $flags & VALID_DOUBLE) {
135 # Caller needs to ensure that set_int, set_double,
136 # set_numeric and set_sv are only invoked on legal lvalues.
139 my ($obj, $expr) = @_;
140 runtime("$obj->{iv} = $expr;");
141 $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE);
142 $obj->{flags} |= VALID_INT;
146 my ($obj, $expr) = @_;
147 runtime("$obj->{nv} = $expr;");
148 $obj->{flags} &= ~(VALID_SV | VALID_INT);
149 $obj->{flags} |= VALID_DOUBLE;
153 my ($obj, $expr) = @_;
154 if ($obj->{type} == T_INT) {
155 $obj->set_int($expr);
157 $obj->set_double($expr);
162 my ($obj, $expr) = @_;
163 runtime("SvSetSV($obj->{sv}, $expr);");
165 $obj->{flags} |= VALID_SV;
172 @B::Stackobj::Padsv::ISA = 'B::Stackobj';
173 sub B::Stackobj::Padsv::new {
174 my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_;
177 flags => VALID_SV | $extra_flags,
178 sv => "PL_curpad[$ix]",
184 sub B::Stackobj::Padsv::load_int {
186 if ($obj->{flags} & VALID_DOUBLE) {
187 runtime("$obj->{iv} = $obj->{nv};");
189 runtime("$obj->{iv} = SvIV($obj->{sv});");
191 $obj->{flags} |= VALID_INT;
194 sub B::Stackobj::Padsv::load_double {
197 runtime("$obj->{nv} = SvNV($obj->{sv});");
198 $obj->{flags} |= VALID_DOUBLE;
201 sub B::Stackobj::Padsv::write_back {
203 my $flags = $obj->{flags};
204 return if $flags & VALID_SV;
205 if ($flags & VALID_INT) {
206 runtime("sv_setiv($obj->{sv}, $obj->{iv});");
207 } elsif ($flags & VALID_DOUBLE) {
208 runtime("sv_setnv($obj->{sv}, $obj->{nv});");
210 confess "write_back failed for lexical @{[$obj->peek]}\n";
212 $obj->{flags} |= VALID_SV;
219 @B::Stackobj::Const::ISA = 'B::Stackobj';
220 sub B::Stackobj::Const::new {
221 my ($class, $sv) = @_;
224 sv => $sv # holds the SV object until write_back happens
226 my $svflags = $sv->FLAGS;
227 if ($svflags & SVf_IOK) {
228 $obj->{flags} = VALID_INT|VALID_DOUBLE;
229 $obj->{type} = T_INT;
230 $obj->{nv} = $obj->{iv} = $sv->IV;
231 } elsif ($svflags & SVf_NOK) {
232 $obj->{flags} = VALID_INT|VALID_DOUBLE;
233 $obj->{type} = T_DOUBLE;
234 $obj->{iv} = $obj->{nv} = $sv->NV;
236 $obj->{type} = T_UNKNOWN;
241 sub B::Stackobj::Const::write_back {
243 return if $obj->{flags} & VALID_SV;
244 # Save the SV object and replace $obj->{sv} by its C source code name
245 $obj->{sv} = $obj->{sv}->save;
246 $obj->{flags} |= VALID_SV|VALID_INT|VALID_DOUBLE;
249 sub B::Stackobj::Const::load_int {
251 $obj->{iv} = int($obj->{sv}->PV);
252 $obj->{flags} |= VALID_INT;
255 sub B::Stackobj::Const::load_double {
257 $obj->{nv} = $obj->{sv}->PV + 0.0;
258 $obj->{flags} |= VALID_DOUBLE;
261 sub B::Stackobj::Const::invalidate {}
267 @B::Stackobj::Bool::ISA = 'B::Stackobj';
268 sub B::Stackobj::Bool::new {
269 my ($class, $preg) = @_;
272 flags => VALID_INT|VALID_DOUBLE,
275 preg => $preg # this holds our ref to the pseudo-reg
280 sub B::Stackobj::Bool::write_back {
282 return if $obj->{flags} & VALID_SV;
283 $obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)";
284 $obj->{flags} |= VALID_SV;
287 # XXX Might want to handle as_double/set_double/load_double?
289 sub B::Stackobj::Bool::invalidate {}
297 B::Stackobj - Helper module for CC backend
309 Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>