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