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;
89 my $type = $obj->{type};
90 my $flags = $obj->{flags};
92 if ($type == T_UNKNOWN) {
94 } elsif ($type == T_INT) {
96 } elsif ($type == T_DOUBLE) {
99 $type = "(illegal type $type)";
101 push(@flags, "VALID_INT") if $flags & VALID_INT;
102 push(@flags, "VALID_DOUBLE") if $flags & VALID_DOUBLE;
103 push(@flags, "VALID_SV") if $flags & VALID_SV;
104 push(@flags, "REGISTER") if $flags & REGISTER;
105 push(@flags, "TEMPORARY") if $flags & TEMPORARY;
106 @flags = ("none") unless @flags;
107 return sprintf("%s type=$type flags=%s sv=$obj->{sv}",
108 class($obj), join("|", @flags));
113 my $type = $obj->{type};
114 my $flags = $obj->{flags};
115 if ($type == T_INT || $flags & VALID_INT) {
117 } elsif ($type == T_DOUBLE || $flags & VALID_DOUBLE) {
125 # Caller needs to ensure that set_int, set_double,
126 # set_numeric and set_sv are only invoked on legal lvalues.
129 my ($obj, $expr) = @_;
130 runtime("$obj->{iv} = $expr;");
131 $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE);
132 $obj->{flags} |= VALID_INT;
136 my ($obj, $expr) = @_;
137 runtime("$obj->{nv} = $expr;");
138 $obj->{flags} &= ~(VALID_SV | VALID_INT);
139 $obj->{flags} |= VALID_DOUBLE;
143 my ($obj, $expr) = @_;
144 if ($obj->{type} == T_INT) {
145 $obj->set_int($expr);
147 $obj->set_double($expr);
152 my ($obj, $expr) = @_;
153 runtime("SvSetSV($obj->{sv}, $expr);");
155 $obj->{flags} |= VALID_SV;
162 @B::Stackobj::Padsv::ISA = 'B::Stackobj';
163 sub B::Stackobj::Padsv::new {
164 my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_;
167 flags => VALID_SV | $extra_flags,
168 sv => "PL_curpad[$ix]",
174 sub B::Stackobj::Padsv::load_int {
176 if ($obj->{flags} & VALID_DOUBLE) {
177 runtime("$obj->{iv} = $obj->{nv};");
179 runtime("$obj->{iv} = SvIV($obj->{sv});");
181 $obj->{flags} |= VALID_INT;
184 sub B::Stackobj::Padsv::load_double {
187 runtime("$obj->{nv} = SvNV($obj->{sv});");
188 $obj->{flags} |= VALID_DOUBLE;
191 sub B::Stackobj::Padsv::write_back {
193 my $flags = $obj->{flags};
194 return if $flags & VALID_SV;
195 if ($flags & VALID_INT) {
196 runtime("sv_setiv($obj->{sv}, $obj->{iv});");
197 } elsif ($flags & VALID_DOUBLE) {
198 runtime("sv_setnv($obj->{sv}, $obj->{nv});");
200 confess "write_back failed for lexical @{[$obj->peek]}\n";
202 $obj->{flags} |= VALID_SV;
209 @B::Stackobj::Const::ISA = 'B::Stackobj';
210 sub B::Stackobj::Const::new {
211 my ($class, $sv) = @_;
214 sv => $sv # holds the SV object until write_back happens
216 my $svflags = $sv->FLAGS;
217 if ($svflags & SVf_IOK) {
218 $obj->{flags} = VALID_INT|VALID_DOUBLE;
219 $obj->{type} = T_INT;
220 $obj->{nv} = $obj->{iv} = $sv->IV;
221 } elsif ($svflags & SVf_NOK) {
222 $obj->{flags} = VALID_INT|VALID_DOUBLE;
223 $obj->{type} = T_DOUBLE;
224 $obj->{iv} = $obj->{nv} = $sv->NV;
226 $obj->{type} = T_UNKNOWN;
231 sub B::Stackobj::Const::write_back {
233 return if $obj->{flags} & VALID_SV;
234 # Save the SV object and replace $obj->{sv} by its C source code name
235 $obj->{sv} = $obj->{sv}->save;
236 $obj->{flags} |= VALID_SV|VALID_INT|VALID_DOUBLE;
239 sub B::Stackobj::Const::load_int {
241 $obj->{iv} = int($obj->{sv}->PV);
242 $obj->{flags} |= VALID_INT;
245 sub B::Stackobj::Const::load_double {
247 $obj->{nv} = $obj->{sv}->PV + 0.0;
248 $obj->{flags} |= VALID_DOUBLE;
251 sub B::Stackobj::Const::invalidate {}
257 @B::Stackobj::Bool::ISA = 'B::Stackobj';
258 sub B::Stackobj::Bool::new {
259 my ($class, $preg) = @_;
262 flags => VALID_INT|VALID_DOUBLE,
265 preg => $preg # this holds our ref to the pseudo-reg
270 sub B::Stackobj::Bool::write_back {
272 return if $obj->{flags} & VALID_SV;
273 $obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)";
274 $obj->{flags} |= VALID_SV;
277 # XXX Might want to handle as_double/set_double/load_double?
279 sub B::Stackobj::Bool::invalidate {}
287 B::Stackobj - Helper module for CC backend
299 Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>