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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 | ||
84 | # | |
85 | # Debugging methods | |
86 | # | |
87 | sub peek { | |
88 | my $obj = shift; | |
89 | my $type = $obj->{type}; | |
90 | my $flags = $obj->{flags}; | |
91 | my @flags; | |
92 | if ($type == T_UNKNOWN) { | |
93 | $type = "T_UNKNOWN"; | |
94 | } elsif ($type == T_INT) { | |
95 | $type = "T_INT"; | |
96 | } elsif ($type == T_DOUBLE) { | |
97 | $type = "T_DOUBLE"; | |
98 | } else { | |
99 | $type = "(illegal type $type)"; | |
100 | } | |
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)); | |
109 | } | |
110 | ||
111 | sub minipeek { | |
112 | my $obj = shift; | |
113 | my $type = $obj->{type}; | |
114 | my $flags = $obj->{flags}; | |
115 | if ($type == T_INT || $flags & VALID_INT) { | |
116 | return $obj->{iv}; | |
117 | } elsif ($type == T_DOUBLE || $flags & VALID_DOUBLE) { | |
118 | return $obj->{nv}; | |
119 | } else { | |
120 | return $obj->{sv}; | |
121 | } | |
122 | } | |
123 | ||
124 | # | |
125 | # Caller needs to ensure that set_int, set_double, | |
126 | # set_numeric and set_sv are only invoked on legal lvalues. | |
127 | # | |
128 | sub set_int { | |
129 | my ($obj, $expr) = @_; | |
130 | runtime("$obj->{iv} = $expr;"); | |
131 | $obj->{flags} &= ~(VALID_SV | VALID_DOUBLE); | |
132 | $obj->{flags} |= VALID_INT; | |
133 | } | |
134 | ||
135 | sub set_double { | |
136 | my ($obj, $expr) = @_; | |
137 | runtime("$obj->{nv} = $expr;"); | |
138 | $obj->{flags} &= ~(VALID_SV | VALID_INT); | |
139 | $obj->{flags} |= VALID_DOUBLE; | |
140 | } | |
141 | ||
142 | sub set_numeric { | |
143 | my ($obj, $expr) = @_; | |
144 | if ($obj->{type} == T_INT) { | |
145 | $obj->set_int($expr); | |
146 | } else { | |
147 | $obj->set_double($expr); | |
148 | } | |
149 | } | |
150 | ||
151 | sub set_sv { | |
152 | my ($obj, $expr) = @_; | |
153 | runtime("SvSetSV($obj->{sv}, $expr);"); | |
154 | $obj->invalidate; | |
155 | $obj->{flags} |= VALID_SV; | |
156 | } | |
157 | ||
158 | # | |
159 | # Stackobj::Padsv | |
160 | # | |
161 | ||
162 | @B::Stackobj::Padsv::ISA = 'B::Stackobj'; | |
163 | sub B::Stackobj::Padsv::new { | |
164 | my ($class, $type, $extra_flags, $ix, $iname, $dname) = @_; | |
165 | bless { | |
166 | type => $type, | |
167 | flags => VALID_SV | $extra_flags, | |
168 | sv => "curpad[$ix]", | |
169 | iv => "$iname", | |
170 | nv => "$dname" | |
171 | }, $class; | |
172 | } | |
173 | ||
174 | sub B::Stackobj::Padsv::load_int { | |
175 | my $obj = shift; | |
176 | if ($obj->{flags} & VALID_DOUBLE) { | |
177 | runtime("$obj->{iv} = $obj->{nv};"); | |
178 | } else { | |
179 | runtime("$obj->{iv} = SvIV($obj->{sv});"); | |
180 | } | |
181 | $obj->{flags} |= VALID_INT; | |
182 | } | |
183 | ||
184 | sub B::Stackobj::Padsv::load_double { | |
185 | my $obj = shift; | |
186 | $obj->write_back; | |
187 | runtime("$obj->{nv} = SvNV($obj->{sv});"); | |
188 | $obj->{flags} |= VALID_DOUBLE; | |
189 | } | |
190 | ||
191 | sub B::Stackobj::Padsv::write_back { | |
192 | my $obj = shift; | |
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}, $obj->{nv});"); | |
199 | } else { | |
200 | confess "write_back failed for lexical @{[$obj->peek]}\n"; | |
201 | } | |
202 | $obj->{flags} |= VALID_SV; | |
203 | } | |
204 | ||
205 | # | |
206 | # Stackobj::Const | |
207 | # | |
208 | ||
209 | @B::Stackobj::Const::ISA = 'B::Stackobj'; | |
210 | sub B::Stackobj::Const::new { | |
211 | my ($class, $sv) = @_; | |
212 | my $obj = bless { | |
213 | flags => 0, | |
214 | sv => $sv # holds the SV object until write_back happens | |
215 | }, $class; | |
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; | |
225 | } else { | |
226 | $obj->{type} = T_UNKNOWN; | |
227 | } | |
228 | return $obj; | |
229 | } | |
230 | ||
231 | sub B::Stackobj::Const::write_back { | |
232 | my $obj = shift; | |
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; | |
237 | } | |
238 | ||
239 | sub B::Stackobj::Const::load_int { | |
240 | my $obj = shift; | |
241 | $obj->{iv} = int($obj->{sv}->PV); | |
242 | $obj->{flags} |= VALID_INT; | |
243 | } | |
244 | ||
245 | sub B::Stackobj::Const::load_double { | |
246 | my $obj = shift; | |
247 | $obj->{nv} = $obj->{sv}->PV + 0.0; | |
248 | $obj->{flags} |= VALID_DOUBLE; | |
249 | } | |
250 | ||
251 | sub B::Stackobj::Const::invalidate {} | |
252 | ||
253 | # | |
254 | # Stackobj::Bool | |
255 | # | |
256 | ||
257 | @B::Stackobj::Bool::ISA = 'B::Stackobj'; | |
258 | sub B::Stackobj::Bool::new { | |
259 | my ($class, $preg) = @_; | |
260 | my $obj = bless { | |
261 | type => T_INT, | |
262 | flags => VALID_INT|VALID_DOUBLE, | |
263 | iv => $$preg, | |
264 | nv => $$preg, | |
265 | preg => $preg # this holds our ref to the pseudo-reg | |
266 | }, $class; | |
267 | return $obj; | |
268 | } | |
269 | ||
270 | sub B::Stackobj::Bool::write_back { | |
271 | my $obj = shift; | |
272 | return if $obj->{flags} & VALID_SV; | |
273 | $obj->{sv} = "($obj->{iv} ? &sv_yes : &sv_no)"; | |
274 | $obj->{flags} |= VALID_SV; | |
275 | } | |
276 | ||
277 | # XXX Might want to handle as_double/set_double/load_double? | |
278 | ||
279 | sub B::Stackobj::Bool::invalidate {} | |
280 | ||
281 | 1; |