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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 | # |
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8 | package B::Stackobj; |
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9 | use Exporter (); |
10 | @ISA = qw(Exporter); |
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11 | @EXPORT_OK = qw(set_callback T_UNKNOWN T_DOUBLE T_INT VALID_UNSIGNED |
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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 |
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15 | VALID_UNSIGNED REGISTER TEMPORARY)]); |
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16 | |
17 | use Carp qw(confess); |
18 | use strict; |
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19 | use B qw(class SVf_IOK SVf_NOK SVf_IVisUV); |
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20 | |
21 | # Types |
22 | sub T_UNKNOWN () { 0 } |
23 | sub T_DOUBLE () { 1 } |
24 | sub T_INT () { 2 } |
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25 | sub T_SPECIAL () { 3 } |
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26 | |
27 | # Flags |
28 | sub VALID_INT () { 0x01 } |
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29 | sub VALID_UNSIGNED () { 0x02 } |
30 | sub VALID_DOUBLE () { 0x04 } |
31 | sub VALID_SV () { 0x08 } |
32 | sub REGISTER () { 0x10 } # no implicit write-back when calling subs |
33 | sub TEMPORARY () { 0x20 } # no implicit write-back needed at all |
34 | sub SAVE_INT () { 0x40 } #if int part needs to be saved at all |
35 | sub SAVE_DOUBLE () { 0x80 } #if double part needs to be saved at all |
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36 | |
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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 | |
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51 | sub invalidate { shift->{flags} &= ~(VALID_INT |VALID_UNSIGNED | VALID_DOUBLE) } |
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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; |
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66 | $obj->{flags} |= VALID_INT|SAVE_INT; |
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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; |
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75 | $obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE; |
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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 | |
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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 | } |
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95 | |
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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 $obj->{sv}; |
133 | } |
134 | } |
135 | |
136 | # |
137 | # Caller needs to ensure that set_int, set_double, |
138 | # set_numeric and set_sv are only invoked on legal lvalues. |
139 | # |
140 | sub set_int { |
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141 | my ($obj, $expr,$unsigned) = @_; |
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142 | runtime("$obj->{iv} = $expr;"); |
143 | $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE); |
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144 | $obj->{flags} |= VALID_INT|SAVE_INT; |
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145 | $obj->{flags} |= VALID_UNSIGNED if $unsigned; |
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146 | } |
147 | |
148 | sub set_double { |
149 | my ($obj, $expr) = @_; |
150 | runtime("$obj->{nv} = $expr;"); |
151 | $obj->{flags} &= ~(VALID_SV | VALID_INT); |
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152 | $obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE; |
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153 | } |
154 | |
155 | sub set_numeric { |
156 | my ($obj, $expr) = @_; |
157 | if ($obj->{type} == T_INT) { |
158 | $obj->set_int($expr); |
159 | } else { |
160 | $obj->set_double($expr); |
161 | } |
162 | } |
163 | |
164 | sub set_sv { |
165 | my ($obj, $expr) = @_; |
166 | runtime("SvSetSV($obj->{sv}, $expr);"); |
167 | $obj->invalidate; |
168 | $obj->{flags} |= VALID_SV; |
169 | } |
170 | |
171 | # |
172 | # Stackobj::Padsv |
173 | # |
174 | |
175 | @B::Stackobj::Padsv::ISA = 'B::Stackobj'; |
176 | sub B::Stackobj::Padsv::new { |
177 | my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_; |
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178 | $extra_flags |= SAVE_INT if $extra_flags & VALID_INT; |
179 | $extra_flags |= SAVE_DOUBLE if $extra_flags & VALID_DOUBLE; |
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180 | bless { |
181 | type => $type, |
182 | flags => VALID_SV | $extra_flags, |
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183 | sv => "PL_curpad[$ix]", |
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184 | iv => "$iname", |
185 | nv => "$dname" |
186 | }, $class; |
187 | } |
188 | |
189 | sub B::Stackobj::Padsv::load_int { |
190 | my $obj = shift; |
191 | if ($obj->{flags} & VALID_DOUBLE) { |
192 | runtime("$obj->{iv} = $obj->{nv};"); |
193 | } else { |
194 | runtime("$obj->{iv} = SvIV($obj->{sv});"); |
195 | } |
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196 | $obj->{flags} |= VALID_INT|SAVE_INT; |
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197 | } |
198 | |
199 | sub B::Stackobj::Padsv::load_double { |
200 | my $obj = shift; |
201 | $obj->write_back; |
202 | runtime("$obj->{nv} = SvNV($obj->{sv});"); |
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203 | $obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE; |
204 | } |
205 | sub B::Stackobj::Padsv::save_int { |
206 | my $obj = shift; |
207 | return $obj->{flags} & SAVE_INT; |
208 | } |
209 | |
210 | sub B::Stackobj::Padsv::save_double { |
211 | my $obj = shift; |
212 | return $obj->{flags} & SAVE_DOUBLE; |
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213 | } |
214 | |
215 | sub B::Stackobj::Padsv::write_back { |
216 | my $obj = shift; |
217 | my $flags = $obj->{flags}; |
218 | return if $flags & VALID_SV; |
219 | if ($flags & VALID_INT) { |
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220 | if ($flags & VALID_UNSIGNED ){ |
221 | runtime("sv_setuv($obj->{sv}, $obj->{iv});"); |
222 | }else{ |
223 | runtime("sv_setiv($obj->{sv}, $obj->{iv});"); |
224 | } |
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225 | } elsif ($flags & VALID_DOUBLE) { |
226 | runtime("sv_setnv($obj->{sv}, $obj->{nv});"); |
227 | } else { |
228 | confess "write_back failed for lexical @{[$obj->peek]}\n"; |
229 | } |
230 | $obj->{flags} |= VALID_SV; |
231 | } |
232 | |
233 | # |
234 | # Stackobj::Const |
235 | # |
236 | |
237 | @B::Stackobj::Const::ISA = 'B::Stackobj'; |
238 | sub B::Stackobj::Const::new { |
239 | my ($class, $sv) = @_; |
240 | my $obj = bless { |
241 | flags => 0, |
242 | sv => $sv # holds the SV object until write_back happens |
243 | }, $class; |
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244 | if ( ref($sv) eq "B::SPECIAL" ){ |
245 | $obj->{type}= T_SPECIAL; |
246 | }else{ |
247 | my $svflags = $sv->FLAGS; |
248 | if ($svflags & SVf_IOK) { |
249 | $obj->{flags} = VALID_INT|VALID_DOUBLE; |
250 | $obj->{type} = T_INT; |
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251 | if ($svflags & SVf_IVisUV){ |
252 | $obj->{flags} |= VALID_UNSIGNED; |
253 | $obj->{nv} = $obj->{iv} = $sv->UVX; |
254 | }else{ |
255 | $obj->{nv} = $obj->{iv} = $sv->IV; |
256 | } |
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257 | } elsif ($svflags & SVf_NOK) { |
258 | $obj->{flags} = VALID_INT|VALID_DOUBLE; |
259 | $obj->{type} = T_DOUBLE; |
260 | $obj->{iv} = $obj->{nv} = $sv->NV; |
261 | } else { |
262 | $obj->{type} = T_UNKNOWN; |
263 | } |
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264 | } |
265 | return $obj; |
266 | } |
267 | |
268 | sub B::Stackobj::Const::write_back { |
269 | my $obj = shift; |
270 | return if $obj->{flags} & VALID_SV; |
271 | # Save the SV object and replace $obj->{sv} by its C source code name |
272 | $obj->{sv} = $obj->{sv}->save; |
273 | $obj->{flags} |= VALID_SV|VALID_INT|VALID_DOUBLE; |
274 | } |
275 | |
276 | sub B::Stackobj::Const::load_int { |
277 | my $obj = shift; |
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278 | if (ref($obj->{sv}) eq "B::RV"){ |
279 | $obj->{iv} = int($obj->{sv}->RV->PV); |
280 | }else{ |
281 | $obj->{iv} = int($obj->{sv}->PV); |
282 | } |
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283 | $obj->{flags} |= VALID_INT; |
284 | } |
285 | |
286 | sub B::Stackobj::Const::load_double { |
287 | my $obj = shift; |
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288 | if (ref($obj->{sv}) eq "B::RV"){ |
289 | $obj->{nv} = $obj->{sv}->RV->PV + 0.0; |
290 | }else{ |
291 | $obj->{nv} = $obj->{sv}->PV + 0.0; |
292 | } |
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293 | $obj->{flags} |= VALID_DOUBLE; |
294 | } |
295 | |
296 | sub B::Stackobj::Const::invalidate {} |
297 | |
298 | # |
299 | # Stackobj::Bool |
300 | # |
301 | |
302 | @B::Stackobj::Bool::ISA = 'B::Stackobj'; |
303 | sub B::Stackobj::Bool::new { |
304 | my ($class, $preg) = @_; |
305 | my $obj = bless { |
306 | type => T_INT, |
307 | flags => VALID_INT|VALID_DOUBLE, |
308 | iv => $$preg, |
309 | nv => $$preg, |
310 | preg => $preg # this holds our ref to the pseudo-reg |
311 | }, $class; |
312 | return $obj; |
313 | } |
314 | |
315 | sub B::Stackobj::Bool::write_back { |
316 | my $obj = shift; |
317 | return if $obj->{flags} & VALID_SV; |
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318 | $obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)"; |
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319 | $obj->{flags} |= VALID_SV; |
320 | } |
321 | |
322 | # XXX Might want to handle as_double/set_double/load_double? |
323 | |
324 | sub B::Stackobj::Bool::invalidate {} |
325 | |
326 | 1; |
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327 | |
328 | __END__ |
329 | |
330 | =head1 NAME |
331 | |
332 | B::Stackobj - Helper module for CC backend |
333 | |
334 | =head1 SYNOPSIS |
335 | |
336 | use B::Stackobj; |
337 | |
338 | =head1 DESCRIPTION |
339 | |
340 | See F<ext/B/README>. |
341 | |
342 | =head1 AUTHOR |
343 | |
344 | Malcolm Beattie, C<mbeattie@sable.ox.ac.uk> |
345 | |
346 | =cut |