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) ;
100 my $type = $obj->{type};
101 my $flags = $obj->{flags};
103 if ($type == T_UNKNOWN) {
105 } elsif ($type == T_INT) {
107 } elsif ($type == T_DOUBLE) {
110 $type = "(illegal type $type)";
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));
124 my $type = $obj->{type};
125 my $flags = $obj->{flags};
126 if ($type == T_INT || $flags & VALID_INT) {
128 } elsif ($type == T_DOUBLE || $flags & VALID_DOUBLE) {
136 # Caller needs to ensure that set_int, set_double,
137 # set_numeric and set_sv are only invoked on legal lvalues.
140 my ($obj, $expr) = @_;
141 runtime("$obj->{iv} = $expr;");
142 $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE);
143 $obj->{flags} |= VALID_INT;
147 my ($obj, $expr) = @_;
148 runtime("$obj->{nv} = $expr;");
149 $obj->{flags} &= ~(VALID_SV | VALID_INT);
150 $obj->{flags} |= VALID_DOUBLE;
154 my ($obj, $expr) = @_;
155 if ($obj->{type} == T_INT) {
156 $obj->set_int($expr);
158 $obj->set_double($expr);
163 my ($obj, $expr) = @_;
164 runtime("SvSetSV($obj->{sv}, $expr);");
166 $obj->{flags} |= VALID_SV;
173 @B::Stackobj::Padsv::ISA = 'B::Stackobj';
174 sub B::Stackobj::Padsv::new {
175 my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_;
178 flags => VALID_SV | $extra_flags,
179 sv => "PL_curpad[$ix]",
185 sub B::Stackobj::Padsv::load_int {
187 if ($obj->{flags} & VALID_DOUBLE) {
188 runtime("$obj->{iv} = $obj->{nv};");
190 runtime("$obj->{iv} = SvIV($obj->{sv});");
192 $obj->{flags} |= VALID_INT;
195 sub B::Stackobj::Padsv::load_double {
198 runtime("$obj->{nv} = SvNV($obj->{sv});");
199 $obj->{flags} |= VALID_DOUBLE;
202 sub B::Stackobj::Padsv::write_back {
204 my $flags = $obj->{flags};
205 return if $flags & VALID_SV;
206 if ($flags & VALID_INT) {
207 runtime("sv_setiv($obj->{sv}, $obj->{iv});");
208 } elsif ($flags & VALID_DOUBLE) {
209 runtime("sv_setnv($obj->{sv}, $obj->{nv});");
211 confess "write_back failed for lexical @{[$obj->peek]}\n";
213 $obj->{flags} |= VALID_SV;
220 @B::Stackobj::Const::ISA = 'B::Stackobj';
221 sub B::Stackobj::Const::new {
222 my ($class, $sv) = @_;
225 sv => $sv # holds the SV object until write_back happens
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;
237 $obj->{type} = T_UNKNOWN;
242 sub B::Stackobj::Const::write_back {
244 return if $obj->{flags} & VALID_SV;
245 # Save the SV object and replace $obj->{sv} by its C source code name
246 $obj->{sv} = $obj->{sv}->save;
247 $obj->{flags} |= VALID_SV|VALID_INT|VALID_DOUBLE;
250 sub B::Stackobj::Const::load_int {
252 $obj->{iv} = int($obj->{sv}->PV);
253 $obj->{flags} |= VALID_INT;
256 sub B::Stackobj::Const::load_double {
258 $obj->{nv} = $obj->{sv}->PV + 0.0;
259 $obj->{flags} |= VALID_DOUBLE;
262 sub B::Stackobj::Const::invalidate {}
268 @B::Stackobj::Bool::ISA = 'B::Stackobj';
269 sub B::Stackobj::Bool::new {
270 my ($class, $preg) = @_;
273 flags => VALID_INT|VALID_DOUBLE,
276 preg => $preg # this holds our ref to the pseudo-reg
281 sub B::Stackobj::Bool::write_back {
283 return if $obj->{flags} & VALID_SV;
284 $obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)";
285 $obj->{flags} |= VALID_SV;
288 # XXX Might want to handle as_double/set_double/load_double?
290 sub B::Stackobj::Bool::invalidate {}
298 B::Stackobj - Helper module for CC backend
310 Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>