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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 | |
10 | our $VERSION = '1.00'; |
11 | |
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12 | use Exporter (); |
13 | @ISA = qw(Exporter); |
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14 | @EXPORT_OK = qw(set_callback T_UNKNOWN T_DOUBLE T_INT VALID_UNSIGNED |
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15 | VALID_INT VALID_DOUBLE VALID_SV REGISTER TEMPORARY); |
16 | %EXPORT_TAGS = (types => [qw(T_UNKNOWN T_DOUBLE T_INT)], |
17 | flags => [qw(VALID_INT VALID_DOUBLE VALID_SV |
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18 | VALID_UNSIGNED REGISTER TEMPORARY)]); |
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19 | |
20 | use Carp qw(confess); |
21 | use strict; |
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22 | use B qw(class SVf_IOK SVf_NOK SVf_IVisUV); |
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23 | |
24 | # Types |
25 | sub T_UNKNOWN () { 0 } |
26 | sub T_DOUBLE () { 1 } |
27 | sub T_INT () { 2 } |
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28 | sub T_SPECIAL () { 3 } |
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29 | |
30 | # Flags |
31 | sub VALID_INT () { 0x01 } |
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32 | sub VALID_UNSIGNED () { 0x02 } |
33 | sub VALID_DOUBLE () { 0x04 } |
34 | sub VALID_SV () { 0x08 } |
35 | sub REGISTER () { 0x10 } # no implicit write-back when calling subs |
36 | sub TEMPORARY () { 0x20 } # no implicit write-back needed at all |
37 | sub SAVE_INT () { 0x40 } #if int part needs to be saved at all |
38 | sub SAVE_DOUBLE () { 0x80 } #if double part needs to be saved at all |
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39 | |
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40 | |
41 | # |
42 | # Callback for runtime code generation |
43 | # |
44 | my $runtime_callback = sub { confess "set_callback not yet called" }; |
45 | sub set_callback (&) { $runtime_callback = shift } |
46 | sub runtime { &$runtime_callback(@_) } |
47 | |
48 | # |
49 | # Methods |
50 | # |
51 | |
52 | sub write_back { confess "stack object does not implement write_back" } |
53 | |
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54 | sub invalidate { shift->{flags} &= ~(VALID_INT |VALID_UNSIGNED | VALID_DOUBLE) } |
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55 | |
56 | sub as_sv { |
57 | my $obj = shift; |
58 | if (!($obj->{flags} & VALID_SV)) { |
59 | $obj->write_back; |
60 | $obj->{flags} |= VALID_SV; |
61 | } |
62 | return $obj->{sv}; |
63 | } |
64 | |
65 | sub as_int { |
66 | my $obj = shift; |
67 | if (!($obj->{flags} & VALID_INT)) { |
68 | $obj->load_int; |
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69 | $obj->{flags} |= VALID_INT|SAVE_INT; |
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70 | } |
71 | return $obj->{iv}; |
72 | } |
73 | |
74 | sub as_double { |
75 | my $obj = shift; |
76 | if (!($obj->{flags} & VALID_DOUBLE)) { |
77 | $obj->load_double; |
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78 | $obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE; |
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79 | } |
80 | return $obj->{nv}; |
81 | } |
82 | |
83 | sub as_numeric { |
84 | my $obj = shift; |
85 | return $obj->{type} == T_INT ? $obj->as_int : $obj->as_double; |
86 | } |
87 | |
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88 | sub as_bool { |
89 | my $obj=shift; |
90 | if ($obj->{flags} & VALID_INT ){ |
91 | return $obj->{iv}; |
92 | } |
93 | if ($obj->{flags} & VALID_DOUBLE ){ |
94 | return $obj->{nv}; |
95 | } |
96 | return sprintf("(SvTRUE(%s))", $obj->as_sv) ; |
97 | } |
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98 | |
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99 | # |
100 | # Debugging methods |
101 | # |
102 | sub peek { |
103 | my $obj = shift; |
104 | my $type = $obj->{type}; |
105 | my $flags = $obj->{flags}; |
106 | my @flags; |
107 | if ($type == T_UNKNOWN) { |
108 | $type = "T_UNKNOWN"; |
109 | } elsif ($type == T_INT) { |
110 | $type = "T_INT"; |
111 | } elsif ($type == T_DOUBLE) { |
112 | $type = "T_DOUBLE"; |
113 | } else { |
114 | $type = "(illegal type $type)"; |
115 | } |
116 | push(@flags, "VALID_INT") if $flags & VALID_INT; |
117 | push(@flags, "VALID_DOUBLE") if $flags & VALID_DOUBLE; |
118 | push(@flags, "VALID_SV") if $flags & VALID_SV; |
119 | push(@flags, "REGISTER") if $flags & REGISTER; |
120 | push(@flags, "TEMPORARY") if $flags & TEMPORARY; |
121 | @flags = ("none") unless @flags; |
122 | return sprintf("%s type=$type flags=%s sv=$obj->{sv}", |
123 | class($obj), join("|", @flags)); |
124 | } |
125 | |
126 | sub minipeek { |
127 | my $obj = shift; |
128 | my $type = $obj->{type}; |
129 | my $flags = $obj->{flags}; |
130 | if ($type == T_INT || $flags & VALID_INT) { |
131 | return $obj->{iv}; |
132 | } elsif ($type == T_DOUBLE || $flags & VALID_DOUBLE) { |
133 | return $obj->{nv}; |
134 | } else { |
135 | return $obj->{sv}; |
136 | } |
137 | } |
138 | |
139 | # |
140 | # Caller needs to ensure that set_int, set_double, |
141 | # set_numeric and set_sv are only invoked on legal lvalues. |
142 | # |
143 | sub set_int { |
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144 | my ($obj, $expr,$unsigned) = @_; |
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145 | runtime("$obj->{iv} = $expr;"); |
146 | $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE); |
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147 | $obj->{flags} |= VALID_INT|SAVE_INT; |
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148 | $obj->{flags} |= VALID_UNSIGNED if $unsigned; |
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149 | } |
150 | |
151 | sub set_double { |
152 | my ($obj, $expr) = @_; |
153 | runtime("$obj->{nv} = $expr;"); |
154 | $obj->{flags} &= ~(VALID_SV | VALID_INT); |
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155 | $obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE; |
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156 | } |
157 | |
158 | sub set_numeric { |
159 | my ($obj, $expr) = @_; |
160 | if ($obj->{type} == T_INT) { |
161 | $obj->set_int($expr); |
162 | } else { |
163 | $obj->set_double($expr); |
164 | } |
165 | } |
166 | |
167 | sub set_sv { |
168 | my ($obj, $expr) = @_; |
169 | runtime("SvSetSV($obj->{sv}, $expr);"); |
170 | $obj->invalidate; |
171 | $obj->{flags} |= VALID_SV; |
172 | } |
173 | |
174 | # |
175 | # Stackobj::Padsv |
176 | # |
177 | |
178 | @B::Stackobj::Padsv::ISA = 'B::Stackobj'; |
179 | sub B::Stackobj::Padsv::new { |
180 | my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_; |
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181 | $extra_flags |= SAVE_INT if $extra_flags & VALID_INT; |
182 | $extra_flags |= SAVE_DOUBLE if $extra_flags & VALID_DOUBLE; |
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183 | bless { |
184 | type => $type, |
185 | flags => VALID_SV | $extra_flags, |
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186 | sv => "PL_curpad[$ix]", |
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187 | iv => "$iname", |
188 | nv => "$dname" |
189 | }, $class; |
190 | } |
191 | |
192 | sub B::Stackobj::Padsv::load_int { |
193 | my $obj = shift; |
194 | if ($obj->{flags} & VALID_DOUBLE) { |
195 | runtime("$obj->{iv} = $obj->{nv};"); |
196 | } else { |
197 | runtime("$obj->{iv} = SvIV($obj->{sv});"); |
198 | } |
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199 | $obj->{flags} |= VALID_INT|SAVE_INT; |
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200 | } |
201 | |
202 | sub B::Stackobj::Padsv::load_double { |
203 | my $obj = shift; |
204 | $obj->write_back; |
205 | runtime("$obj->{nv} = SvNV($obj->{sv});"); |
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206 | $obj->{flags} |= VALID_DOUBLE|SAVE_DOUBLE; |
207 | } |
208 | sub B::Stackobj::Padsv::save_int { |
209 | my $obj = shift; |
210 | return $obj->{flags} & SAVE_INT; |
211 | } |
212 | |
213 | sub B::Stackobj::Padsv::save_double { |
214 | my $obj = shift; |
215 | return $obj->{flags} & SAVE_DOUBLE; |
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216 | } |
217 | |
218 | sub B::Stackobj::Padsv::write_back { |
219 | my $obj = shift; |
220 | my $flags = $obj->{flags}; |
221 | return if $flags & VALID_SV; |
222 | if ($flags & VALID_INT) { |
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223 | if ($flags & VALID_UNSIGNED ){ |
224 | runtime("sv_setuv($obj->{sv}, $obj->{iv});"); |
225 | }else{ |
226 | runtime("sv_setiv($obj->{sv}, $obj->{iv});"); |
227 | } |
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228 | } elsif ($flags & VALID_DOUBLE) { |
229 | runtime("sv_setnv($obj->{sv}, $obj->{nv});"); |
230 | } else { |
231 | confess "write_back failed for lexical @{[$obj->peek]}\n"; |
232 | } |
233 | $obj->{flags} |= VALID_SV; |
234 | } |
235 | |
236 | # |
237 | # Stackobj::Const |
238 | # |
239 | |
240 | @B::Stackobj::Const::ISA = 'B::Stackobj'; |
241 | sub B::Stackobj::Const::new { |
242 | my ($class, $sv) = @_; |
243 | my $obj = bless { |
244 | flags => 0, |
245 | sv => $sv # holds the SV object until write_back happens |
246 | }, $class; |
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247 | if ( ref($sv) eq "B::SPECIAL" ){ |
248 | $obj->{type}= T_SPECIAL; |
249 | }else{ |
250 | my $svflags = $sv->FLAGS; |
251 | if ($svflags & SVf_IOK) { |
252 | $obj->{flags} = VALID_INT|VALID_DOUBLE; |
253 | $obj->{type} = T_INT; |
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254 | if ($svflags & SVf_IVisUV){ |
255 | $obj->{flags} |= VALID_UNSIGNED; |
256 | $obj->{nv} = $obj->{iv} = $sv->UVX; |
257 | }else{ |
258 | $obj->{nv} = $obj->{iv} = $sv->IV; |
259 | } |
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260 | } elsif ($svflags & SVf_NOK) { |
261 | $obj->{flags} = VALID_INT|VALID_DOUBLE; |
262 | $obj->{type} = T_DOUBLE; |
263 | $obj->{iv} = $obj->{nv} = $sv->NV; |
264 | } else { |
265 | $obj->{type} = T_UNKNOWN; |
266 | } |
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267 | } |
268 | return $obj; |
269 | } |
270 | |
271 | sub B::Stackobj::Const::write_back { |
272 | my $obj = shift; |
273 | return if $obj->{flags} & VALID_SV; |
274 | # Save the SV object and replace $obj->{sv} by its C source code name |
275 | $obj->{sv} = $obj->{sv}->save; |
276 | $obj->{flags} |= VALID_SV|VALID_INT|VALID_DOUBLE; |
277 | } |
278 | |
279 | sub B::Stackobj::Const::load_int { |
280 | my $obj = shift; |
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281 | if (ref($obj->{sv}) eq "B::RV"){ |
282 | $obj->{iv} = int($obj->{sv}->RV->PV); |
283 | }else{ |
284 | $obj->{iv} = int($obj->{sv}->PV); |
285 | } |
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286 | $obj->{flags} |= VALID_INT; |
287 | } |
288 | |
289 | sub B::Stackobj::Const::load_double { |
290 | my $obj = shift; |
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291 | if (ref($obj->{sv}) eq "B::RV"){ |
292 | $obj->{nv} = $obj->{sv}->RV->PV + 0.0; |
293 | }else{ |
294 | $obj->{nv} = $obj->{sv}->PV + 0.0; |
295 | } |
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296 | $obj->{flags} |= VALID_DOUBLE; |
297 | } |
298 | |
299 | sub B::Stackobj::Const::invalidate {} |
300 | |
301 | # |
302 | # Stackobj::Bool |
303 | # |
304 | |
305 | @B::Stackobj::Bool::ISA = 'B::Stackobj'; |
306 | sub B::Stackobj::Bool::new { |
307 | my ($class, $preg) = @_; |
308 | my $obj = bless { |
309 | type => T_INT, |
310 | flags => VALID_INT|VALID_DOUBLE, |
311 | iv => $$preg, |
312 | nv => $$preg, |
313 | preg => $preg # this holds our ref to the pseudo-reg |
314 | }, $class; |
315 | return $obj; |
316 | } |
317 | |
318 | sub B::Stackobj::Bool::write_back { |
319 | my $obj = shift; |
320 | return if $obj->{flags} & VALID_SV; |
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321 | $obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)"; |
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322 | $obj->{flags} |= VALID_SV; |
323 | } |
324 | |
325 | # XXX Might want to handle as_double/set_double/load_double? |
326 | |
327 | sub B::Stackobj::Bool::invalidate {} |
328 | |
329 | 1; |
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330 | |
331 | __END__ |
332 | |
333 | =head1 NAME |
334 | |
335 | B::Stackobj - Helper module for CC backend |
336 | |
337 | =head1 SYNOPSIS |
338 | |
339 | use B::Stackobj; |
340 | |
341 | =head1 DESCRIPTION |
342 | |
343 | See F<ext/B/README>. |
344 | |
345 | =head1 AUTHOR |
346 | |
347 | Malcolm Beattie, C<mbeattie@sable.ox.ac.uk> |
348 | |
349 | =cut |