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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 | # |
8 | package B::Stackobj; |
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; |
19 | use B qw(class); |
20 | |
21 | # Perl internal constants that I should probably define elsewhere. |
22 | sub SVf_IOK () { 0x10000 } |
23 | sub SVf_NOK () { 0x20000 } |
24 | |
25 | # Types |
26 | sub T_UNKNOWN () { 0 } |
27 | sub T_DOUBLE () { 1 } |
28 | sub T_INT () { 2 } |
29 | |
30 | # Flags |
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 |
36 | |
37 | # |
38 | # Callback for runtime code generation |
39 | # |
40 | my $runtime_callback = sub { confess "set_callback not yet called" }; |
41 | sub set_callback (&) { $runtime_callback = shift } |
42 | sub runtime { &$runtime_callback(@_) } |
43 | |
44 | # |
45 | # Methods |
46 | # |
47 | |
48 | sub write_back { confess "stack object does not implement write_back" } |
49 | |
50 | sub invalidate { shift->{flags} &= ~(VALID_INT | VALID_DOUBLE) } |
51 | |
52 | sub as_sv { |
53 | my $obj = shift; |
54 | if (!($obj->{flags} & VALID_SV)) { |
55 | $obj->write_back; |
56 | $obj->{flags} |= VALID_SV; |
57 | } |
58 | return $obj->{sv}; |
59 | } |
60 | |
61 | sub as_int { |
62 | my $obj = shift; |
63 | if (!($obj->{flags} & VALID_INT)) { |
64 | $obj->load_int; |
65 | $obj->{flags} |= VALID_INT; |
66 | } |
67 | return $obj->{iv}; |
68 | } |
69 | |
70 | sub as_double { |
71 | my $obj = shift; |
72 | if (!($obj->{flags} & VALID_DOUBLE)) { |
73 | $obj->load_double; |
74 | $obj->{flags} |= VALID_DOUBLE; |
75 | } |
76 | return $obj->{nv}; |
77 | } |
78 | |
79 | sub as_numeric { |
80 | my $obj = shift; |
81 | return $obj->{type} == T_INT ? $obj->as_int : $obj->as_double; |
82 | } |
83 | |
a9b6343a |
84 | sub as_bool { |
85 | my $obj=shift; |
86 | if ($obj->{flags} & VALID_INT ){ |
87 | return $obj->{iv}; |
88 | } |
89 | if ($obj->{flags} & VALID_DOUBLE ){ |
90 | return $obj->{nv}; |
91 | } |
92 | return sprintf("(SvTRUE(%s))", $obj->as_sv) ; |
93 | } |
a798dbf2 |
94 | # |
95 | # Debugging methods |
96 | # |
97 | sub peek { |
98 | my $obj = shift; |
99 | my $type = $obj->{type}; |
100 | my $flags = $obj->{flags}; |
101 | my @flags; |
102 | if ($type == T_UNKNOWN) { |
103 | $type = "T_UNKNOWN"; |
104 | } elsif ($type == T_INT) { |
105 | $type = "T_INT"; |
106 | } elsif ($type == T_DOUBLE) { |
107 | $type = "T_DOUBLE"; |
108 | } else { |
109 | $type = "(illegal type $type)"; |
110 | } |
111 | push(@flags, "VALID_INT") if $flags & VALID_INT; |
112 | push(@flags, "VALID_DOUBLE") if $flags & VALID_DOUBLE; |
113 | push(@flags, "VALID_SV") if $flags & VALID_SV; |
114 | push(@flags, "REGISTER") if $flags & REGISTER; |
115 | push(@flags, "TEMPORARY") if $flags & TEMPORARY; |
116 | @flags = ("none") unless @flags; |
117 | return sprintf("%s type=$type flags=%s sv=$obj->{sv}", |
118 | class($obj), join("|", @flags)); |
119 | } |
120 | |
121 | sub minipeek { |
122 | my $obj = shift; |
123 | my $type = $obj->{type}; |
124 | my $flags = $obj->{flags}; |
125 | if ($type == T_INT || $flags & VALID_INT) { |
126 | return $obj->{iv}; |
127 | } elsif ($type == T_DOUBLE || $flags & VALID_DOUBLE) { |
128 | return $obj->{nv}; |
129 | } else { |
130 | return $obj->{sv}; |
131 | } |
132 | } |
133 | |
134 | # |
135 | # Caller needs to ensure that set_int, set_double, |
136 | # set_numeric and set_sv are only invoked on legal lvalues. |
137 | # |
138 | sub set_int { |
139 | my ($obj, $expr) = @_; |
140 | runtime("$obj->{iv} = $expr;"); |
141 | $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE); |
142 | $obj->{flags} |= VALID_INT; |
143 | } |
144 | |
145 | sub set_double { |
146 | my ($obj, $expr) = @_; |
147 | runtime("$obj->{nv} = $expr;"); |
148 | $obj->{flags} &= ~(VALID_SV | VALID_INT); |
149 | $obj->{flags} |= VALID_DOUBLE; |
150 | } |
151 | |
152 | sub set_numeric { |
153 | my ($obj, $expr) = @_; |
154 | if ($obj->{type} == T_INT) { |
155 | $obj->set_int($expr); |
156 | } else { |
157 | $obj->set_double($expr); |
158 | } |
159 | } |
160 | |
161 | sub set_sv { |
162 | my ($obj, $expr) = @_; |
163 | runtime("SvSetSV($obj->{sv}, $expr);"); |
164 | $obj->invalidate; |
165 | $obj->{flags} |= VALID_SV; |
166 | } |
167 | |
168 | # |
169 | # Stackobj::Padsv |
170 | # |
171 | |
172 | @B::Stackobj::Padsv::ISA = 'B::Stackobj'; |
173 | sub B::Stackobj::Padsv::new { |
174 | my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_; |
175 | bless { |
176 | type => $type, |
177 | flags => VALID_SV | $extra_flags, |
81009501 |
178 | sv => "PL_curpad[$ix]", |
a798dbf2 |
179 | iv => "$iname", |
180 | nv => "$dname" |
181 | }, $class; |
182 | } |
183 | |
184 | sub B::Stackobj::Padsv::load_int { |
185 | my $obj = shift; |
186 | if ($obj->{flags} & VALID_DOUBLE) { |
187 | runtime("$obj->{iv} = $obj->{nv};"); |
188 | } else { |
189 | runtime("$obj->{iv} = SvIV($obj->{sv});"); |
190 | } |
191 | $obj->{flags} |= VALID_INT; |
192 | } |
193 | |
194 | sub B::Stackobj::Padsv::load_double { |
195 | my $obj = shift; |
196 | $obj->write_back; |
197 | runtime("$obj->{nv} = SvNV($obj->{sv});"); |
198 | $obj->{flags} |= VALID_DOUBLE; |
199 | } |
200 | |
201 | sub B::Stackobj::Padsv::write_back { |
202 | my $obj = shift; |
203 | my $flags = $obj->{flags}; |
204 | return if $flags & VALID_SV; |
205 | if ($flags & VALID_INT) { |
206 | runtime("sv_setiv($obj->{sv}, $obj->{iv});"); |
207 | } elsif ($flags & VALID_DOUBLE) { |
208 | runtime("sv_setnv($obj->{sv}, $obj->{nv});"); |
209 | } else { |
210 | confess "write_back failed for lexical @{[$obj->peek]}\n"; |
211 | } |
212 | $obj->{flags} |= VALID_SV; |
213 | } |
214 | |
215 | # |
216 | # Stackobj::Const |
217 | # |
218 | |
219 | @B::Stackobj::Const::ISA = 'B::Stackobj'; |
220 | sub B::Stackobj::Const::new { |
221 | my ($class, $sv) = @_; |
222 | my $obj = bless { |
223 | flags => 0, |
224 | sv => $sv # holds the SV object until write_back happens |
225 | }, $class; |
226 | my $svflags = $sv->FLAGS; |
227 | if ($svflags & SVf_IOK) { |
228 | $obj->{flags} = VALID_INT|VALID_DOUBLE; |
229 | $obj->{type} = T_INT; |
230 | $obj->{nv} = $obj->{iv} = $sv->IV; |
231 | } elsif ($svflags & SVf_NOK) { |
232 | $obj->{flags} = VALID_INT|VALID_DOUBLE; |
233 | $obj->{type} = T_DOUBLE; |
234 | $obj->{iv} = $obj->{nv} = $sv->NV; |
235 | } else { |
236 | $obj->{type} = T_UNKNOWN; |
237 | } |
238 | return $obj; |
239 | } |
240 | |
241 | sub B::Stackobj::Const::write_back { |
242 | my $obj = shift; |
243 | return if $obj->{flags} & VALID_SV; |
244 | # Save the SV object and replace $obj->{sv} by its C source code name |
245 | $obj->{sv} = $obj->{sv}->save; |
246 | $obj->{flags} |= VALID_SV|VALID_INT|VALID_DOUBLE; |
247 | } |
248 | |
249 | sub B::Stackobj::Const::load_int { |
250 | my $obj = shift; |
251 | $obj->{iv} = int($obj->{sv}->PV); |
252 | $obj->{flags} |= VALID_INT; |
253 | } |
254 | |
255 | sub B::Stackobj::Const::load_double { |
256 | my $obj = shift; |
257 | $obj->{nv} = $obj->{sv}->PV + 0.0; |
258 | $obj->{flags} |= VALID_DOUBLE; |
259 | } |
260 | |
261 | sub B::Stackobj::Const::invalidate {} |
262 | |
263 | # |
264 | # Stackobj::Bool |
265 | # |
266 | |
267 | @B::Stackobj::Bool::ISA = 'B::Stackobj'; |
268 | sub B::Stackobj::Bool::new { |
269 | my ($class, $preg) = @_; |
270 | my $obj = bless { |
271 | type => T_INT, |
272 | flags => VALID_INT|VALID_DOUBLE, |
273 | iv => $$preg, |
274 | nv => $$preg, |
275 | preg => $preg # this holds our ref to the pseudo-reg |
276 | }, $class; |
277 | return $obj; |
278 | } |
279 | |
280 | sub B::Stackobj::Bool::write_back { |
281 | my $obj = shift; |
282 | return if $obj->{flags} & VALID_SV; |
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283 | $obj->{sv} = "($obj->{iv} ? &PL_sv_yes : &PL_sv_no)"; |
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284 | $obj->{flags} |= VALID_SV; |
285 | } |
286 | |
287 | # XXX Might want to handle as_double/set_double/load_double? |
288 | |
289 | sub B::Stackobj::Bool::invalidate {} |
290 | |
291 | 1; |
7f20e9dd |
292 | |
293 | __END__ |
294 | |
295 | =head1 NAME |
296 | |
297 | B::Stackobj - Helper module for CC backend |
298 | |
299 | =head1 SYNOPSIS |
300 | |
301 | use B::Stackobj; |
302 | |
303 | =head1 DESCRIPTION |
304 | |
305 | See F<ext/B/README>. |
306 | |
307 | =head1 AUTHOR |
308 | |
309 | Malcolm Beattie, C<mbeattie@sable.ox.ac.uk> |
310 | |
311 | =cut |