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1 | /* Basic data types for Objective C. |
2 | Copyright (C) 1998 Free Software Foundation, Inc. | |
3 | Contributed by Ovidiu Predescu. | |
4 | ||
5 | This file is part of GNU CC. | |
6 | ||
7 | GNU CC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GNU CC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GNU CC; see the file COPYING. If not, write to | |
19 | the Free Software Foundation, 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
21 | ||
22 | /* As a special exception, if you link this library with files | |
23 | compiled with GCC to produce an executable, this does not cause | |
24 | the resulting executable to be covered by the GNU General Public License. | |
25 | This exception does not however invalidate any other reasons why | |
26 | the executable file might be covered by the GNU General Public License. */ | |
27 | ||
28 | #include "../tconfig.h" | |
29 | #include "objc.h" | |
30 | #include "encoding.h" | |
31 | ||
32 | #include <assert.h> | |
33 | #include <string.h> | |
34 | ||
35 | #if OBJC_WITH_GC | |
36 | ||
37 | #include <gc.h> | |
38 | ||
39 | /* gc_typed.h uses the following but doesn't declare them */ | |
40 | typedef GC_word word; | |
41 | typedef GC_signed_word signed_word; | |
42 | ||
43 | #if BITS_PER_WORD == 32 | |
44 | # define LOGWL 5 | |
45 | # define modWORDSZ(n) ((n) & 0x1f) /* n mod size of word */ | |
46 | #endif | |
47 | ||
48 | #if BITS_PER_WORD == 64 | |
49 | # define LOGWL 6 | |
50 | # define modWORDSZ(n) ((n) & 0x3f) /* n mod size of word */ | |
51 | #endif | |
52 | ||
53 | #define divWORDSZ(n) ((n) >> LOGWL) /* divide n by size of word */ | |
54 | ||
55 | #include <gc_typed.h> | |
56 | ||
57 | /* The following functions set up in `mask` the corresponding pointers. | |
58 | The offset is incremented with the size of the type. */ | |
59 | ||
60 | #define ROUND(V, A) \ | |
61 | ({ typeof(V) __v=(V); typeof(A) __a=(A); \ | |
62 | __a*((__v+__a-1)/__a); }) | |
63 | ||
64 | #define SET_BIT_FOR_OFFSET(mask, offset) \ | |
65 | GC_set_bit(mask, offset / sizeof (void*)) | |
66 | ||
67 | /* Some prototypes */ | |
68 | static void | |
69 | __objc_gc_setup_struct (GC_bitmap mask, const char *type, int offset); | |
70 | static void | |
71 | __objc_gc_setup_union (GC_bitmap mask, const char *type, int offset); | |
72 | ||
73 | ||
74 | static void | |
75 | __objc_gc_setup_array (GC_bitmap mask, const char *type, int offset) | |
76 | { | |
77 | int i, len = atoi(type + 1); | |
78 | ||
79 | while (isdigit(*++type)) | |
80 | /* do nothing */; /* skip the size of the array */ | |
81 | ||
82 | switch (*type) { | |
83 | case _C_ARY_B: | |
84 | for (i = 0; i < len; i++) | |
85 | __objc_gc_setup_array (mask, type, offset); | |
86 | break; | |
87 | ||
88 | case _C_STRUCT_B: | |
89 | for (i = 0; i < len; i++) | |
90 | __objc_gc_setup_struct (mask, type, offset); | |
91 | break; | |
92 | ||
93 | case _C_UNION_B: | |
94 | for (i = 0; i < len; i++) | |
95 | __objc_gc_setup_union (mask, type, offset); | |
96 | break; | |
97 | ||
98 | default: | |
99 | break; | |
100 | } | |
101 | } | |
102 | ||
103 | static void | |
104 | __objc_gc_setup_struct (GC_bitmap mask, const char *type, int offset) | |
105 | { | |
106 | struct objc_struct_layout layout; | |
107 | unsigned int position; | |
108 | const char *mtype; | |
109 | ||
110 | objc_layout_structure (type, &layout); | |
111 | ||
112 | while (objc_layout_structure_next_member (&layout)) | |
113 | { | |
114 | BOOL gc_invisible = NO; | |
115 | ||
116 | objc_layout_structure_get_info (&layout, &position, NULL, &mtype); | |
117 | ||
118 | /* Skip the variable name */ | |
119 | if (*mtype == '"') | |
120 | { | |
121 | for (mtype++; *mtype++ != '"';) | |
122 | /* do nothing */; | |
123 | } | |
124 | ||
125 | if (*mtype == _C_GCINVISIBLE) | |
126 | { | |
127 | gc_invisible = YES; | |
128 | mtype++; | |
129 | } | |
130 | ||
131 | /* Add to position the offset of this structure */ | |
132 | position += offset; | |
133 | ||
134 | switch (*mtype) { | |
135 | case _C_ID: | |
136 | case _C_CLASS: | |
137 | case _C_SEL: | |
138 | case _C_PTR: | |
139 | case _C_CHARPTR: | |
140 | case _C_ATOM: | |
141 | if (!gc_invisible) | |
142 | SET_BIT_FOR_OFFSET(mask, position); | |
143 | break; | |
144 | ||
145 | case _C_ARY_B: | |
146 | __objc_gc_setup_array (mask, mtype, position); | |
147 | break; | |
148 | ||
149 | case _C_STRUCT_B: | |
150 | __objc_gc_setup_struct (mask, mtype, position); | |
151 | break; | |
152 | ||
153 | case _C_UNION_B: | |
154 | __objc_gc_setup_union (mask, mtype, position); | |
155 | break; | |
156 | ||
157 | default: | |
158 | break; | |
159 | } | |
160 | } | |
161 | } | |
162 | ||
163 | static void | |
164 | __objc_gc_setup_union (GC_bitmap mask, const char *type, int offset) | |
165 | { | |
166 | /* Sub-optimal, quick implementation: assume the union is made of | |
167 | pointers, set up the mask accordingly. */ | |
168 | ||
169 | int i, size, align; | |
170 | ||
171 | /* Skip the variable name */ | |
172 | if (*type == '"') | |
173 | { | |
174 | for (type++; *type++ != '"';) | |
175 | /* do nothing */; | |
176 | } | |
177 | ||
178 | size = objc_sizeof_type (type); | |
179 | align = objc_alignof_type (type); | |
180 | ||
181 | offset = ROUND(offset, align); | |
182 | for (i = 0; i < size; i += sizeof (void*)) | |
183 | { | |
184 | SET_BIT_FOR_OFFSET(mask, offset); | |
185 | offset += sizeof (void*); | |
186 | } | |
187 | } | |
188 | ||
189 | ||
190 | /* Iterates over the types in the structure that represents the class | |
191 | encoding and sets the bits in mask according to each ivar type. */ | |
192 | static void | |
193 | __objc_gc_type_description_from_type (GC_bitmap mask, const char *type) | |
194 | { | |
195 | struct objc_struct_layout layout; | |
196 | unsigned int offset, align; | |
197 | const char *ivar_type; | |
198 | ||
199 | objc_layout_structure (type, &layout); | |
200 | ||
201 | while (objc_layout_structure_next_member (&layout)) | |
202 | { | |
203 | BOOL gc_invisible = NO; | |
204 | ||
205 | objc_layout_structure_get_info (&layout, &offset, &align, &ivar_type); | |
206 | ||
207 | /* Skip the variable name */ | |
208 | if (*ivar_type == '"') | |
209 | { | |
210 | for (ivar_type++; *ivar_type++ != '"';) | |
211 | /* do nothing */; | |
212 | } | |
213 | ||
214 | if (*ivar_type == _C_GCINVISIBLE) | |
215 | { | |
216 | gc_invisible = YES; | |
217 | ivar_type++; | |
218 | } | |
219 | ||
220 | switch (*ivar_type) { | |
221 | case _C_ID: | |
222 | case _C_CLASS: | |
223 | case _C_SEL: | |
224 | case _C_PTR: | |
225 | case _C_CHARPTR: | |
226 | if (!gc_invisible) | |
227 | SET_BIT_FOR_OFFSET(mask, offset); | |
228 | break; | |
229 | ||
230 | case _C_ARY_B: | |
231 | __objc_gc_setup_array (mask, ivar_type, offset); | |
232 | break; | |
233 | ||
234 | case _C_STRUCT_B: | |
235 | __objc_gc_setup_struct (mask, ivar_type, offset); | |
236 | break; | |
237 | ||
238 | case _C_UNION_B: | |
239 | __objc_gc_setup_union (mask, ivar_type, offset); | |
240 | break; | |
241 | ||
242 | default: | |
243 | break; | |
244 | } | |
245 | } | |
246 | } | |
247 | ||
248 | /* Computes in *type the full type encoding of this class including | |
249 | its super classes. '*size' gives the total number of bytes allocated | |
250 | into *type, '*current' the number of bytes used so far by the | |
251 | encoding. */ | |
252 | static void | |
253 | __objc_class_structure_encoding (Class class, char **type, int *size, | |
254 | int *current) | |
255 | { | |
256 | int i, ivar_count; | |
257 | struct objc_ivar_list* ivars; | |
258 | ||
259 | if (!class) | |
260 | { | |
261 | strcat (*type, "{"); | |
262 | *current++; | |
263 | return; | |
264 | } | |
265 | ||
266 | /* Add the type encodings of the super classes */ | |
267 | __objc_class_structure_encoding (class->super_class, type, size, current); | |
268 | ||
269 | ivars = class->ivars; | |
270 | if (!ivars) | |
271 | return; | |
272 | ||
273 | ivar_count = ivars->ivar_count; | |
274 | ||
275 | for (i = 0; i < ivar_count; i++) | |
276 | { | |
277 | struct objc_ivar *ivar = &(ivars->ivar_list[i]); | |
278 | const char *ivar_type = ivar->ivar_type; | |
279 | int len = strlen (ivar_type); | |
280 | ||
281 | if (*current + len + 1 >= *size) | |
282 | { | |
283 | /* Increase the size of the encoding string so that it | |
284 | contains this ivar's type. */ | |
285 | *size = ROUND(*current + len + 1, 10); | |
286 | *type = objc_realloc (*type, *size); | |
287 | } | |
288 | strcat (*type + *current, ivar_type); | |
289 | *current += len; | |
290 | } | |
291 | } | |
292 | ||
293 | ||
294 | /* Allocates the memory that will hold the type description for class | |
295 | and calls the __objc_class_structure_encoding that generates this | |
296 | value. */ | |
297 | void | |
298 | __objc_generate_gc_type_description (Class class) | |
299 | { | |
300 | GC_bitmap mask; | |
301 | int bits_no, size; | |
302 | int type_size = 10, current; | |
303 | char *class_structure_type; | |
304 | ||
305 | if (!CLS_ISCLASS(class)) | |
306 | return; | |
307 | ||
308 | /* We have to create a mask in which each bit counts for a pointer member. | |
309 | We take into consideration all the non-pointer instance variables and we | |
310 | round them up to the alignment. */ | |
311 | ||
312 | /* The number of bits in the mask is the size of an instance in bytes divided | |
313 | by the size of a pointer. */ | |
314 | bits_no = (ROUND(class_get_instance_size (class), sizeof(void*)) | |
315 | / sizeof (void*)); | |
316 | size = ROUND(bits_no, BITS_PER_WORD) / BITS_PER_WORD; | |
317 | mask = objc_atomic_malloc (size * sizeof (int)); | |
318 | memset (mask, 0, size * sizeof (int)); | |
319 | ||
320 | class_structure_type = objc_atomic_malloc (type_size); | |
321 | *class_structure_type = current = 0; | |
322 | __objc_class_structure_encoding (class, &class_structure_type, | |
323 | &type_size, ¤t); | |
324 | if (current + 1 == type_size) | |
325 | class_structure_type = objc_realloc (class_structure_type, ++type_size); | |
326 | strcat (class_structure_type + current, "}"); | |
327 | // printf ("type description for '%s' is %s\n", class->name, class_structure_type); | |
328 | ||
329 | __objc_gc_type_description_from_type (mask, class_structure_type); | |
330 | objc_free (class_structure_type); | |
331 | ||
332 | #define DEBUG 1 | |
333 | #ifdef DEBUG | |
334 | printf (" mask for '%s', type '%s' (bits %d, mask size %d) is:", | |
335 | class_structure_type, class->name, bits_no, size); | |
336 | { | |
337 | int i; | |
338 | for (i = 0; i < size; i++) | |
339 | printf (" %lx", mask[i]); | |
340 | } | |
341 | puts (""); | |
342 | #endif | |
343 | ||
344 | class->gc_object_type = (void*)GC_make_descriptor (mask, bits_no); | |
345 | } | |
346 | ||
347 | ||
348 | /* Returns YES if type denotes a pointer type, NO otherwise */ | |
349 | static inline BOOL | |
350 | __objc_ivar_pointer (const char *type) | |
351 | { | |
352 | type = objc_skip_type_qualifiers (type); | |
353 | ||
354 | return (*type == _C_ID | |
355 | || *type == _C_CLASS | |
356 | || *type == _C_SEL | |
357 | || *type == _C_PTR | |
358 | || *type == _C_CHARPTR | |
359 | || *type == _C_ATOM); | |
360 | } | |
361 | ||
362 | ||
363 | /* Mark the instance variable whose name is given by ivarname as a | |
364 | weak pointer (a pointer hidden to the garbage collector) if | |
365 | gc_invisible is true. If gc_invisible is false it unmarks the | |
366 | instance variable and makes it a normal pointer, visible to the | |
367 | garbage collector. | |
368 | ||
369 | This operation only makes sense on instance variables that are | |
370 | pointers. */ | |
371 | void | |
372 | class_ivar_set_gcinvisible (Class class, const char* ivarname, | |
373 | BOOL gc_invisible) | |
374 | { | |
375 | int i, ivar_count; | |
376 | struct objc_ivar_list* ivars; | |
377 | ||
378 | if (!class || !ivarname) | |
379 | return; | |
380 | ||
381 | ivars = class->ivars; | |
382 | if (!ivars) | |
383 | return; | |
384 | ||
385 | ivar_count = ivars->ivar_count; | |
386 | ||
387 | for (i = 0; i < ivar_count; i++) | |
388 | { | |
389 | struct objc_ivar *ivar = &(ivars->ivar_list[i]); | |
390 | const char *type; | |
391 | ||
392 | if (!ivar->ivar_name || strcmp (ivar->ivar_name, ivarname)) | |
393 | continue; | |
394 | ||
395 | assert (ivar->ivar_type); | |
396 | type = ivar->ivar_type; | |
397 | ||
398 | /* Skip the variable name */ | |
399 | if (*type == '"') | |
400 | { | |
401 | for (type++; *type++ != '"';) | |
402 | /* do nothing */; | |
403 | } | |
404 | ||
405 | if (*type == _C_GCINVISIBLE) | |
406 | { | |
407 | char *new_type; | |
408 | ||
409 | if (gc_invisible || !__objc_ivar_pointer (type)) | |
410 | return; /* The type of the variable already matches the | |
411 | requested gc_invisible type */ | |
412 | ||
413 | /* The variable is gc_invisible and we have to reverse it */ | |
414 | new_type = objc_atomic_malloc (strlen (ivar->ivar_type)); | |
415 | strncpy (new_type, ivar->ivar_type, | |
416 | (size_t)(type - ivar->ivar_type)); | |
417 | strcat (new_type, type + 1); | |
418 | ivar->ivar_type = new_type; | |
419 | } | |
420 | else | |
421 | { | |
422 | char *new_type; | |
423 | ||
424 | if (!gc_invisible || !__objc_ivar_pointer (type)) | |
425 | return; /* The type of the variable already matches the | |
426 | requested gc_invisible type */ | |
427 | ||
428 | /* The variable is gc visible and we have to make it gc_invisible */ | |
429 | new_type = objc_malloc (strlen (ivar->ivar_type) + 2); | |
430 | strncpy (new_type, ivar->ivar_type, | |
431 | (size_t)(type - ivar->ivar_type)); | |
432 | strcat (new_type, "!"); | |
433 | strcat (new_type, type); | |
434 | ivar->ivar_type = new_type; | |
435 | } | |
436 | ||
437 | __objc_generate_gc_type_description (class); | |
438 | return; | |
439 | } | |
440 | ||
441 | /* Search the instance variable in the superclasses */ | |
442 | class_ivar_set_gcinvisible (class->super_class, ivarname, gc_invisible); | |
443 | } | |
444 | ||
445 | #else /* !OBJC_WITH_GC */ | |
446 | ||
447 | void | |
448 | __objc_generate_gc_type_description (Class class) | |
449 | { | |
450 | } | |
451 | ||
452 | void class_ivar_set_gcinvisible (Class class, | |
453 | const char* ivarname, | |
454 | BOOL gc_invisible) | |
455 | { | |
456 | } | |
457 | ||
458 | #endif /* OBJC_WITH_GC */ |