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7ed49443 JB |
1 | /* Abstraction of GNU v3 abi. |
2 | Contributed by Jim Blandy <jimb@redhat.com> | |
451fbdda | 3 | |
0b302171 | 4 | Copyright (C) 2001-2003, 2005-2012 Free Software Foundation, Inc. |
7ed49443 JB |
5 | |
6 | This file is part of GDB. | |
7 | ||
a9762ec7 JB |
8 | This program is free software; you can redistribute it and/or modify |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 3 of the License, or | |
11 | (at your option) any later version. | |
7ed49443 JB |
12 | |
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
7ed49443 JB |
20 | |
21 | #include "defs.h" | |
22 | #include "value.h" | |
23 | #include "cp-abi.h" | |
362ff856 | 24 | #include "cp-support.h" |
7ed49443 | 25 | #include "demangle.h" |
b18be20d | 26 | #include "objfiles.h" |
0d5de010 | 27 | #include "valprint.h" |
94af9270 | 28 | #include "c-lang.h" |
0d5de010 | 29 | |
3d499020 | 30 | #include "gdb_assert.h" |
5f8a3188 | 31 | #include "gdb_string.h" |
7ed49443 | 32 | |
b27b8843 | 33 | static struct cp_abi_ops gnu_v3_abi_ops; |
7ed49443 JB |
34 | |
35 | static int | |
36 | gnuv3_is_vtable_name (const char *name) | |
37 | { | |
38 | return strncmp (name, "_ZTV", 4) == 0; | |
39 | } | |
40 | ||
41 | static int | |
42 | gnuv3_is_operator_name (const char *name) | |
43 | { | |
44 | return strncmp (name, "operator", 8) == 0; | |
45 | } | |
46 | ||
47 | ||
48 | /* To help us find the components of a vtable, we build ourselves a | |
49 | GDB type object representing the vtable structure. Following the | |
50 | V3 ABI, it goes something like this: | |
51 | ||
52 | struct gdb_gnu_v3_abi_vtable { | |
53 | ||
54 | / * An array of virtual call and virtual base offsets. The real | |
55 | length of this array depends on the class hierarchy; we use | |
56 | negative subscripts to access the elements. Yucky, but | |
57 | better than the alternatives. * / | |
58 | ptrdiff_t vcall_and_vbase_offsets[0]; | |
59 | ||
60 | / * The offset from a virtual pointer referring to this table | |
61 | to the top of the complete object. * / | |
62 | ptrdiff_t offset_to_top; | |
63 | ||
64 | / * The type_info pointer for this class. This is really a | |
65 | std::type_info *, but GDB doesn't really look at the | |
66 | type_info object itself, so we don't bother to get the type | |
67 | exactly right. * / | |
68 | void *type_info; | |
69 | ||
70 | / * Virtual table pointers in objects point here. * / | |
71 | ||
72 | / * Virtual function pointers. Like the vcall/vbase array, the | |
73 | real length of this table depends on the class hierarchy. * / | |
74 | void (*virtual_functions[0]) (); | |
75 | ||
76 | }; | |
77 | ||
78 | The catch, of course, is that the exact layout of this table | |
79 | depends on the ABI --- word size, endianness, alignment, etc. So | |
80 | the GDB type object is actually a per-architecture kind of thing. | |
81 | ||
82 | vtable_type_gdbarch_data is a gdbarch per-architecture data pointer | |
83 | which refers to the struct type * for this structure, laid out | |
84 | appropriately for the architecture. */ | |
b27b8843 | 85 | static struct gdbarch_data *vtable_type_gdbarch_data; |
7ed49443 JB |
86 | |
87 | ||
88 | /* Human-readable names for the numbers of the fields above. */ | |
89 | enum { | |
90 | vtable_field_vcall_and_vbase_offsets, | |
91 | vtable_field_offset_to_top, | |
92 | vtable_field_type_info, | |
93 | vtable_field_virtual_functions | |
94 | }; | |
95 | ||
96 | ||
97 | /* Return a GDB type representing `struct gdb_gnu_v3_abi_vtable', | |
98 | described above, laid out appropriately for ARCH. | |
99 | ||
100 | We use this function as the gdbarch per-architecture data | |
9970f04b | 101 | initialization function. */ |
7ed49443 JB |
102 | static void * |
103 | build_gdb_vtable_type (struct gdbarch *arch) | |
104 | { | |
105 | struct type *t; | |
106 | struct field *field_list, *field; | |
107 | int offset; | |
108 | ||
109 | struct type *void_ptr_type | |
fde6c819 | 110 | = builtin_type (arch)->builtin_data_ptr; |
7ed49443 | 111 | struct type *ptr_to_void_fn_type |
fde6c819 | 112 | = builtin_type (arch)->builtin_func_ptr; |
7ed49443 JB |
113 | |
114 | /* ARCH can't give us the true ptrdiff_t type, so we guess. */ | |
115 | struct type *ptrdiff_type | |
e9bb382b | 116 | = arch_integer_type (arch, gdbarch_ptr_bit (arch), 0, "ptrdiff_t"); |
7ed49443 JB |
117 | |
118 | /* We assume no padding is necessary, since GDB doesn't know | |
119 | anything about alignment at the moment. If this assumption bites | |
120 | us, we should add a gdbarch method which, given a type, returns | |
121 | the alignment that type requires, and then use that here. */ | |
122 | ||
123 | /* Build the field list. */ | |
124 | field_list = xmalloc (sizeof (struct field [4])); | |
125 | memset (field_list, 0, sizeof (struct field [4])); | |
126 | field = &field_list[0]; | |
127 | offset = 0; | |
128 | ||
129 | /* ptrdiff_t vcall_and_vbase_offsets[0]; */ | |
130 | FIELD_NAME (*field) = "vcall_and_vbase_offsets"; | |
e3506a9f | 131 | FIELD_TYPE (*field) = lookup_array_range_type (ptrdiff_type, 0, -1); |
7ed49443 JB |
132 | FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; |
133 | offset += TYPE_LENGTH (FIELD_TYPE (*field)); | |
134 | field++; | |
135 | ||
136 | /* ptrdiff_t offset_to_top; */ | |
137 | FIELD_NAME (*field) = "offset_to_top"; | |
138 | FIELD_TYPE (*field) = ptrdiff_type; | |
139 | FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; | |
140 | offset += TYPE_LENGTH (FIELD_TYPE (*field)); | |
141 | field++; | |
142 | ||
143 | /* void *type_info; */ | |
144 | FIELD_NAME (*field) = "type_info"; | |
145 | FIELD_TYPE (*field) = void_ptr_type; | |
146 | FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; | |
147 | offset += TYPE_LENGTH (FIELD_TYPE (*field)); | |
148 | field++; | |
149 | ||
150 | /* void (*virtual_functions[0]) (); */ | |
151 | FIELD_NAME (*field) = "virtual_functions"; | |
e3506a9f | 152 | FIELD_TYPE (*field) = lookup_array_range_type (ptr_to_void_fn_type, 0, -1); |
7ed49443 JB |
153 | FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; |
154 | offset += TYPE_LENGTH (FIELD_TYPE (*field)); | |
155 | field++; | |
156 | ||
157 | /* We assumed in the allocation above that there were four fields. */ | |
3d499020 | 158 | gdb_assert (field == (field_list + 4)); |
7ed49443 | 159 | |
e9bb382b | 160 | t = arch_type (arch, TYPE_CODE_STRUCT, offset, NULL); |
7ed49443 JB |
161 | TYPE_NFIELDS (t) = field - field_list; |
162 | TYPE_FIELDS (t) = field_list; | |
163 | TYPE_TAG_NAME (t) = "gdb_gnu_v3_abi_vtable"; | |
e9bb382b | 164 | INIT_CPLUS_SPECIFIC (t); |
7ed49443 JB |
165 | |
166 | return t; | |
167 | } | |
168 | ||
169 | ||
ed09d7da KB |
170 | /* Return the ptrdiff_t type used in the vtable type. */ |
171 | static struct type * | |
172 | vtable_ptrdiff_type (struct gdbarch *gdbarch) | |
173 | { | |
174 | struct type *vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data); | |
175 | ||
176 | /* The "offset_to_top" field has the appropriate (ptrdiff_t) type. */ | |
177 | return TYPE_FIELD_TYPE (vtable_type, vtable_field_offset_to_top); | |
178 | } | |
179 | ||
7ed49443 JB |
180 | /* Return the offset from the start of the imaginary `struct |
181 | gdb_gnu_v3_abi_vtable' object to the vtable's "address point" | |
182 | (i.e., where objects' virtual table pointers point). */ | |
183 | static int | |
ad4820ab | 184 | vtable_address_point_offset (struct gdbarch *gdbarch) |
7ed49443 | 185 | { |
ad4820ab | 186 | struct type *vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data); |
7ed49443 JB |
187 | |
188 | return (TYPE_FIELD_BITPOS (vtable_type, vtable_field_virtual_functions) | |
189 | / TARGET_CHAR_BIT); | |
190 | } | |
191 | ||
192 | ||
d48cc9dd DJ |
193 | /* Determine whether structure TYPE is a dynamic class. Cache the |
194 | result. */ | |
195 | ||
196 | static int | |
197 | gnuv3_dynamic_class (struct type *type) | |
198 | { | |
199 | int fieldnum, fieldelem; | |
200 | ||
201 | if (TYPE_CPLUS_DYNAMIC (type)) | |
202 | return TYPE_CPLUS_DYNAMIC (type) == 1; | |
203 | ||
204 | ALLOCATE_CPLUS_STRUCT_TYPE (type); | |
205 | ||
206 | for (fieldnum = 0; fieldnum < TYPE_N_BASECLASSES (type); fieldnum++) | |
207 | if (BASETYPE_VIA_VIRTUAL (type, fieldnum) | |
208 | || gnuv3_dynamic_class (TYPE_FIELD_TYPE (type, fieldnum))) | |
209 | { | |
210 | TYPE_CPLUS_DYNAMIC (type) = 1; | |
211 | return 1; | |
212 | } | |
213 | ||
214 | for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++) | |
215 | for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum); | |
216 | fieldelem++) | |
217 | { | |
218 | struct fn_field *f = TYPE_FN_FIELDLIST1 (type, fieldnum); | |
219 | ||
220 | if (TYPE_FN_FIELD_VIRTUAL_P (f, fieldelem)) | |
221 | { | |
222 | TYPE_CPLUS_DYNAMIC (type) = 1; | |
223 | return 1; | |
224 | } | |
225 | } | |
226 | ||
227 | TYPE_CPLUS_DYNAMIC (type) = -1; | |
228 | return 0; | |
229 | } | |
230 | ||
231 | /* Find the vtable for a value of CONTAINER_TYPE located at | |
232 | CONTAINER_ADDR. Return a value of the correct vtable type for this | |
233 | architecture, or NULL if CONTAINER does not have a vtable. */ | |
234 | ||
235 | static struct value * | |
236 | gnuv3_get_vtable (struct gdbarch *gdbarch, | |
237 | struct type *container_type, CORE_ADDR container_addr) | |
238 | { | |
239 | struct type *vtable_type = gdbarch_data (gdbarch, | |
240 | vtable_type_gdbarch_data); | |
241 | struct type *vtable_pointer_type; | |
242 | struct value *vtable_pointer; | |
243 | CORE_ADDR vtable_address; | |
244 | ||
245 | /* If this type does not have a virtual table, don't read the first | |
246 | field. */ | |
247 | if (!gnuv3_dynamic_class (check_typedef (container_type))) | |
248 | return NULL; | |
249 | ||
250 | /* We do not consult the debug information to find the virtual table. | |
251 | The ABI specifies that it is always at offset zero in any class, | |
252 | and debug information may not represent it. | |
253 | ||
254 | We avoid using value_contents on principle, because the object might | |
255 | be large. */ | |
256 | ||
257 | /* Find the type "pointer to virtual table". */ | |
258 | vtable_pointer_type = lookup_pointer_type (vtable_type); | |
259 | ||
260 | /* Load it from the start of the class. */ | |
261 | vtable_pointer = value_at (vtable_pointer_type, container_addr); | |
262 | vtable_address = value_as_address (vtable_pointer); | |
263 | ||
264 | /* Correct it to point at the start of the virtual table, rather | |
265 | than the address point. */ | |
266 | return value_at_lazy (vtable_type, | |
0963b4bd MS |
267 | vtable_address |
268 | - vtable_address_point_offset (gdbarch)); | |
d48cc9dd DJ |
269 | } |
270 | ||
271 | ||
7ed49443 JB |
272 | static struct type * |
273 | gnuv3_rtti_type (struct value *value, | |
274 | int *full_p, int *top_p, int *using_enc_p) | |
275 | { | |
ad4820ab | 276 | struct gdbarch *gdbarch; |
df407dfe | 277 | struct type *values_type = check_typedef (value_type (value)); |
7ed49443 JB |
278 | struct value *vtable; |
279 | struct minimal_symbol *vtable_symbol; | |
280 | const char *vtable_symbol_name; | |
281 | const char *class_name; | |
7ed49443 JB |
282 | struct type *run_time_type; |
283 | LONGEST offset_to_top; | |
284 | ||
285 | /* We only have RTTI for class objects. */ | |
df407dfe | 286 | if (TYPE_CODE (values_type) != TYPE_CODE_CLASS) |
7ed49443 JB |
287 | return NULL; |
288 | ||
eb2a6f42 TT |
289 | /* Java doesn't have RTTI following the C++ ABI. */ |
290 | if (TYPE_CPLUS_REALLY_JAVA (values_type)) | |
291 | return NULL; | |
292 | ||
ad4820ab | 293 | /* Determine architecture. */ |
50810684 | 294 | gdbarch = get_type_arch (values_type); |
7ed49443 | 295 | |
21cfb3b6 DJ |
296 | if (using_enc_p) |
297 | *using_enc_p = 0; | |
298 | ||
d48cc9dd DJ |
299 | vtable = gnuv3_get_vtable (gdbarch, value_type (value), |
300 | value_as_address (value_addr (value))); | |
301 | if (vtable == NULL) | |
302 | return NULL; | |
303 | ||
7ed49443 JB |
304 | /* Find the linker symbol for this vtable. */ |
305 | vtable_symbol | |
42ae5230 | 306 | = lookup_minimal_symbol_by_pc (value_address (vtable) |
13c3b5f5 | 307 | + value_embedded_offset (vtable)); |
7ed49443 JB |
308 | if (! vtable_symbol) |
309 | return NULL; | |
310 | ||
311 | /* The symbol's demangled name should be something like "vtable for | |
312 | CLASS", where CLASS is the name of the run-time type of VALUE. | |
313 | If we didn't like this approach, we could instead look in the | |
314 | type_info object itself to get the class name. But this way | |
315 | should work just as well, and doesn't read target memory. */ | |
316 | vtable_symbol_name = SYMBOL_DEMANGLED_NAME (vtable_symbol); | |
98081e55 PB |
317 | if (vtable_symbol_name == NULL |
318 | || strncmp (vtable_symbol_name, "vtable for ", 11)) | |
f773fdbb | 319 | { |
8a3fe4f8 | 320 | warning (_("can't find linker symbol for virtual table for `%s' value"), |
0a07729b | 321 | TYPE_SAFE_NAME (values_type)); |
f773fdbb | 322 | if (vtable_symbol_name) |
8a3fe4f8 | 323 | warning (_(" found `%s' instead"), vtable_symbol_name); |
f773fdbb JM |
324 | return NULL; |
325 | } | |
7ed49443 JB |
326 | class_name = vtable_symbol_name + 11; |
327 | ||
328 | /* Try to look up the class name as a type name. */ | |
0963b4bd | 329 | /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */ |
362ff856 MC |
330 | run_time_type = cp_lookup_rtti_type (class_name, NULL); |
331 | if (run_time_type == NULL) | |
332 | return NULL; | |
7ed49443 JB |
333 | |
334 | /* Get the offset from VALUE to the top of the complete object. | |
335 | NOTE: this is the reverse of the meaning of *TOP_P. */ | |
336 | offset_to_top | |
337 | = value_as_long (value_field (vtable, vtable_field_offset_to_top)); | |
338 | ||
339 | if (full_p) | |
13c3b5f5 | 340 | *full_p = (- offset_to_top == value_embedded_offset (value) |
4754a64e | 341 | && (TYPE_LENGTH (value_enclosing_type (value)) |
7ed49443 JB |
342 | >= TYPE_LENGTH (run_time_type))); |
343 | if (top_p) | |
344 | *top_p = - offset_to_top; | |
7ed49443 JB |
345 | return run_time_type; |
346 | } | |
347 | ||
0d5de010 DJ |
348 | /* Return a function pointer for CONTAINER's VTABLE_INDEX'th virtual |
349 | function, of type FNTYPE. */ | |
7ed49443 | 350 | |
0d5de010 | 351 | static struct value * |
ad4820ab UW |
352 | gnuv3_get_virtual_fn (struct gdbarch *gdbarch, struct value *container, |
353 | struct type *fntype, int vtable_index) | |
0d5de010 | 354 | { |
d48cc9dd DJ |
355 | struct value *vtable, *vfn; |
356 | ||
357 | /* Every class with virtual functions must have a vtable. */ | |
358 | vtable = gnuv3_get_vtable (gdbarch, value_type (container), | |
359 | value_as_address (value_addr (container))); | |
360 | gdb_assert (vtable != NULL); | |
7ed49443 JB |
361 | |
362 | /* Fetch the appropriate function pointer from the vtable. */ | |
363 | vfn = value_subscript (value_field (vtable, vtable_field_virtual_functions), | |
2497b498 | 364 | vtable_index); |
7ed49443 | 365 | |
0d5de010 DJ |
366 | /* If this architecture uses function descriptors directly in the vtable, |
367 | then the address of the vtable entry is actually a "function pointer" | |
368 | (i.e. points to the descriptor). We don't need to scale the index | |
369 | by the size of a function descriptor; GCC does that before outputing | |
370 | debug information. */ | |
ad4820ab | 371 | if (gdbarch_vtable_function_descriptors (gdbarch)) |
0d5de010 | 372 | vfn = value_addr (vfn); |
7ed49443 | 373 | |
0d5de010 DJ |
374 | /* Cast the function pointer to the appropriate type. */ |
375 | vfn = value_cast (lookup_pointer_type (fntype), vfn); | |
76b79d6e | 376 | |
7ed49443 JB |
377 | return vfn; |
378 | } | |
379 | ||
0d5de010 DJ |
380 | /* GNU v3 implementation of value_virtual_fn_field. See cp-abi.h |
381 | for a description of the arguments. */ | |
382 | ||
383 | static struct value * | |
384 | gnuv3_virtual_fn_field (struct value **value_p, | |
385 | struct fn_field *f, int j, | |
386 | struct type *vfn_base, int offset) | |
387 | { | |
388 | struct type *values_type = check_typedef (value_type (*value_p)); | |
ad4820ab | 389 | struct gdbarch *gdbarch; |
0d5de010 DJ |
390 | |
391 | /* Some simple sanity checks. */ | |
392 | if (TYPE_CODE (values_type) != TYPE_CODE_CLASS) | |
393 | error (_("Only classes can have virtual functions.")); | |
394 | ||
ad4820ab | 395 | /* Determine architecture. */ |
50810684 | 396 | gdbarch = get_type_arch (values_type); |
ad4820ab | 397 | |
0d5de010 DJ |
398 | /* Cast our value to the base class which defines this virtual |
399 | function. This takes care of any necessary `this' | |
400 | adjustments. */ | |
401 | if (vfn_base != values_type) | |
402 | *value_p = value_cast (vfn_base, *value_p); | |
403 | ||
ad4820ab | 404 | return gnuv3_get_virtual_fn (gdbarch, *value_p, TYPE_FN_FIELD_TYPE (f, j), |
0d5de010 DJ |
405 | TYPE_FN_FIELD_VOFFSET (f, j)); |
406 | } | |
407 | ||
1514d34e DJ |
408 | /* Compute the offset of the baseclass which is |
409 | the INDEXth baseclass of class TYPE, | |
410 | for value at VALADDR (in host) at ADDRESS (in target). | |
411 | The result is the offset of the baseclass value relative | |
412 | to (the address of)(ARG) + OFFSET. | |
413 | ||
0963b4bd MS |
414 | -1 is returned on error. */ |
415 | ||
b9362cc7 | 416 | static int |
8af8e3bc PA |
417 | gnuv3_baseclass_offset (struct type *type, int index, |
418 | const bfd_byte *valaddr, int embedded_offset, | |
419 | CORE_ADDR address, const struct value *val) | |
1514d34e | 420 | { |
ad4820ab | 421 | struct gdbarch *gdbarch; |
ad4820ab | 422 | struct type *ptr_type; |
79d5b63a | 423 | struct value *vtable; |
2497b498 | 424 | struct value *vbase_array; |
1514d34e | 425 | long int cur_base_offset, base_offset; |
1514d34e | 426 | |
ad4820ab | 427 | /* Determine architecture. */ |
50810684 | 428 | gdbarch = get_type_arch (type); |
ad4820ab UW |
429 | ptr_type = builtin_type (gdbarch)->builtin_data_ptr; |
430 | ||
1514d34e DJ |
431 | /* If it isn't a virtual base, this is easy. The offset is in the |
432 | type definition. */ | |
433 | if (!BASETYPE_VIA_VIRTUAL (type, index)) | |
434 | return TYPE_BASECLASS_BITPOS (type, index) / 8; | |
435 | ||
436 | /* To access a virtual base, we need to use the vbase offset stored in | |
437 | our vtable. Recent GCC versions provide this information. If it isn't | |
438 | available, we could get what we needed from RTTI, or from drawing the | |
439 | complete inheritance graph based on the debug info. Neither is | |
440 | worthwhile. */ | |
441 | cur_base_offset = TYPE_BASECLASS_BITPOS (type, index) / 8; | |
ad4820ab | 442 | if (cur_base_offset >= - vtable_address_point_offset (gdbarch)) |
8a3fe4f8 | 443 | error (_("Expected a negative vbase offset (old compiler?)")); |
1514d34e | 444 | |
ad4820ab UW |
445 | cur_base_offset = cur_base_offset + vtable_address_point_offset (gdbarch); |
446 | if ((- cur_base_offset) % TYPE_LENGTH (ptr_type) != 0) | |
8a3fe4f8 | 447 | error (_("Misaligned vbase offset.")); |
ad4820ab | 448 | cur_base_offset = cur_base_offset / ((int) TYPE_LENGTH (ptr_type)); |
1514d34e | 449 | |
8af8e3bc | 450 | vtable = gnuv3_get_vtable (gdbarch, type, address + embedded_offset); |
d48cc9dd | 451 | gdb_assert (vtable != NULL); |
1514d34e | 452 | vbase_array = value_field (vtable, vtable_field_vcall_and_vbase_offsets); |
2497b498 | 453 | base_offset = value_as_long (value_subscript (vbase_array, cur_base_offset)); |
1514d34e DJ |
454 | return base_offset; |
455 | } | |
7ed49443 | 456 | |
0d5de010 DJ |
457 | /* Locate a virtual method in DOMAIN or its non-virtual base classes |
458 | which has virtual table index VOFFSET. The method has an associated | |
459 | "this" adjustment of ADJUSTMENT bytes. */ | |
460 | ||
2c0b251b | 461 | static const char * |
0d5de010 DJ |
462 | gnuv3_find_method_in (struct type *domain, CORE_ADDR voffset, |
463 | LONGEST adjustment) | |
464 | { | |
465 | int i; | |
0d5de010 DJ |
466 | |
467 | /* Search this class first. */ | |
0d5de010 DJ |
468 | if (adjustment == 0) |
469 | { | |
470 | int len; | |
471 | ||
472 | len = TYPE_NFN_FIELDS (domain); | |
473 | for (i = 0; i < len; i++) | |
474 | { | |
475 | int len2, j; | |
476 | struct fn_field *f; | |
477 | ||
478 | f = TYPE_FN_FIELDLIST1 (domain, i); | |
479 | len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i); | |
480 | ||
481 | check_stub_method_group (domain, i); | |
482 | for (j = 0; j < len2; j++) | |
483 | if (TYPE_FN_FIELD_VOFFSET (f, j) == voffset) | |
484 | return TYPE_FN_FIELD_PHYSNAME (f, j); | |
485 | } | |
486 | } | |
487 | ||
488 | /* Next search non-virtual bases. If it's in a virtual base, | |
489 | we're out of luck. */ | |
490 | for (i = 0; i < TYPE_N_BASECLASSES (domain); i++) | |
491 | { | |
492 | int pos; | |
493 | struct type *basetype; | |
494 | ||
495 | if (BASETYPE_VIA_VIRTUAL (domain, i)) | |
496 | continue; | |
497 | ||
498 | pos = TYPE_BASECLASS_BITPOS (domain, i) / 8; | |
499 | basetype = TYPE_FIELD_TYPE (domain, i); | |
500 | /* Recurse with a modified adjustment. We don't need to adjust | |
501 | voffset. */ | |
502 | if (adjustment >= pos && adjustment < pos + TYPE_LENGTH (basetype)) | |
503 | return gnuv3_find_method_in (basetype, voffset, adjustment - pos); | |
504 | } | |
505 | ||
506 | return NULL; | |
507 | } | |
508 | ||
fead6908 UW |
509 | /* Decode GNU v3 method pointer. */ |
510 | ||
511 | static int | |
ad4820ab UW |
512 | gnuv3_decode_method_ptr (struct gdbarch *gdbarch, |
513 | const gdb_byte *contents, | |
fead6908 UW |
514 | CORE_ADDR *value_p, |
515 | LONGEST *adjustment_p) | |
516 | { | |
ad4820ab | 517 | struct type *funcptr_type = builtin_type (gdbarch)->builtin_func_ptr; |
ed09d7da | 518 | struct type *offset_type = vtable_ptrdiff_type (gdbarch); |
e17a4113 | 519 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
fead6908 UW |
520 | CORE_ADDR ptr_value; |
521 | LONGEST voffset, adjustment; | |
522 | int vbit; | |
523 | ||
524 | /* Extract the pointer to member. The first element is either a pointer | |
525 | or a vtable offset. For pointers, we need to use extract_typed_address | |
526 | to allow the back-end to convert the pointer to a GDB address -- but | |
527 | vtable offsets we must handle as integers. At this point, we do not | |
528 | yet know which case we have, so we extract the value under both | |
529 | interpretations and choose the right one later on. */ | |
530 | ptr_value = extract_typed_address (contents, funcptr_type); | |
e17a4113 UW |
531 | voffset = extract_signed_integer (contents, |
532 | TYPE_LENGTH (funcptr_type), byte_order); | |
fead6908 | 533 | contents += TYPE_LENGTH (funcptr_type); |
e17a4113 UW |
534 | adjustment = extract_signed_integer (contents, |
535 | TYPE_LENGTH (offset_type), byte_order); | |
fead6908 | 536 | |
ad4820ab | 537 | if (!gdbarch_vbit_in_delta (gdbarch)) |
fead6908 UW |
538 | { |
539 | vbit = voffset & 1; | |
540 | voffset = voffset ^ vbit; | |
541 | } | |
542 | else | |
543 | { | |
544 | vbit = adjustment & 1; | |
545 | adjustment = adjustment >> 1; | |
546 | } | |
547 | ||
548 | *value_p = vbit? voffset : ptr_value; | |
549 | *adjustment_p = adjustment; | |
550 | return vbit; | |
551 | } | |
552 | ||
0d5de010 DJ |
553 | /* GNU v3 implementation of cplus_print_method_ptr. */ |
554 | ||
555 | static void | |
556 | gnuv3_print_method_ptr (const gdb_byte *contents, | |
557 | struct type *type, | |
558 | struct ui_file *stream) | |
559 | { | |
ad4820ab | 560 | struct type *domain = TYPE_DOMAIN_TYPE (type); |
50810684 | 561 | struct gdbarch *gdbarch = get_type_arch (domain); |
0d5de010 DJ |
562 | CORE_ADDR ptr_value; |
563 | LONGEST adjustment; | |
0d5de010 DJ |
564 | int vbit; |
565 | ||
0d5de010 | 566 | /* Extract the pointer to member. */ |
ad4820ab | 567 | vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment); |
0d5de010 DJ |
568 | |
569 | /* Check for NULL. */ | |
570 | if (ptr_value == 0 && vbit == 0) | |
571 | { | |
572 | fprintf_filtered (stream, "NULL"); | |
573 | return; | |
574 | } | |
575 | ||
576 | /* Search for a virtual method. */ | |
577 | if (vbit) | |
578 | { | |
579 | CORE_ADDR voffset; | |
580 | const char *physname; | |
581 | ||
582 | /* It's a virtual table offset, maybe in this class. Search | |
583 | for a field with the correct vtable offset. First convert it | |
584 | to an index, as used in TYPE_FN_FIELD_VOFFSET. */ | |
ed09d7da | 585 | voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch)); |
0d5de010 DJ |
586 | |
587 | physname = gnuv3_find_method_in (domain, voffset, adjustment); | |
588 | ||
589 | /* If we found a method, print that. We don't bother to disambiguate | |
590 | possible paths to the method based on the adjustment. */ | |
591 | if (physname) | |
592 | { | |
593 | char *demangled_name = cplus_demangle (physname, | |
594 | DMGL_ANSI | DMGL_PARAMS); | |
d8734c88 | 595 | |
94af9270 KS |
596 | fprintf_filtered (stream, "&virtual "); |
597 | if (demangled_name == NULL) | |
598 | fputs_filtered (physname, stream); | |
599 | else | |
0d5de010 | 600 | { |
0d5de010 DJ |
601 | fputs_filtered (demangled_name, stream); |
602 | xfree (demangled_name); | |
0d5de010 | 603 | } |
94af9270 | 604 | return; |
0d5de010 DJ |
605 | } |
606 | } | |
94af9270 KS |
607 | else if (ptr_value != 0) |
608 | { | |
609 | /* Found a non-virtual function: print out the type. */ | |
610 | fputs_filtered ("(", stream); | |
611 | c_print_type (type, "", stream, -1, 0); | |
612 | fputs_filtered (") ", stream); | |
613 | } | |
0d5de010 DJ |
614 | |
615 | /* We didn't find it; print the raw data. */ | |
616 | if (vbit) | |
617 | { | |
618 | fprintf_filtered (stream, "&virtual table offset "); | |
619 | print_longest (stream, 'd', 1, ptr_value); | |
620 | } | |
621 | else | |
5af949e3 | 622 | print_address_demangle (gdbarch, ptr_value, stream, demangle); |
0d5de010 DJ |
623 | |
624 | if (adjustment) | |
625 | { | |
626 | fprintf_filtered (stream, ", this adjustment "); | |
627 | print_longest (stream, 'd', 1, adjustment); | |
628 | } | |
629 | } | |
630 | ||
631 | /* GNU v3 implementation of cplus_method_ptr_size. */ | |
632 | ||
633 | static int | |
ad4820ab | 634 | gnuv3_method_ptr_size (struct type *type) |
0d5de010 | 635 | { |
561d3825 | 636 | struct gdbarch *gdbarch = get_type_arch (type); |
d8734c88 | 637 | |
ad4820ab | 638 | return 2 * TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr); |
0d5de010 DJ |
639 | } |
640 | ||
641 | /* GNU v3 implementation of cplus_make_method_ptr. */ | |
642 | ||
643 | static void | |
ad4820ab UW |
644 | gnuv3_make_method_ptr (struct type *type, gdb_byte *contents, |
645 | CORE_ADDR value, int is_virtual) | |
0d5de010 | 646 | { |
561d3825 | 647 | struct gdbarch *gdbarch = get_type_arch (type); |
ad4820ab | 648 | int size = TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr); |
e17a4113 | 649 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
0d5de010 DJ |
650 | |
651 | /* FIXME drow/2006-12-24: The adjustment of "this" is currently | |
652 | always zero, since the method pointer is of the correct type. | |
653 | But if the method pointer came from a base class, this is | |
654 | incorrect - it should be the offset to the base. The best | |
655 | fix might be to create the pointer to member pointing at the | |
656 | base class and cast it to the derived class, but that requires | |
657 | support for adjusting pointers to members when casting them - | |
658 | not currently supported by GDB. */ | |
659 | ||
ad4820ab | 660 | if (!gdbarch_vbit_in_delta (gdbarch)) |
0d5de010 | 661 | { |
e17a4113 UW |
662 | store_unsigned_integer (contents, size, byte_order, value | is_virtual); |
663 | store_unsigned_integer (contents + size, size, byte_order, 0); | |
0d5de010 DJ |
664 | } |
665 | else | |
666 | { | |
e17a4113 UW |
667 | store_unsigned_integer (contents, size, byte_order, value); |
668 | store_unsigned_integer (contents + size, size, byte_order, is_virtual); | |
0d5de010 DJ |
669 | } |
670 | } | |
671 | ||
672 | /* GNU v3 implementation of cplus_method_ptr_to_value. */ | |
673 | ||
674 | static struct value * | |
675 | gnuv3_method_ptr_to_value (struct value **this_p, struct value *method_ptr) | |
676 | { | |
ad4820ab | 677 | struct gdbarch *gdbarch; |
0d5de010 DJ |
678 | const gdb_byte *contents = value_contents (method_ptr); |
679 | CORE_ADDR ptr_value; | |
ad4820ab | 680 | struct type *domain_type, *final_type, *method_type; |
0d5de010 | 681 | LONGEST adjustment; |
0d5de010 DJ |
682 | int vbit; |
683 | ||
ad4820ab UW |
684 | domain_type = TYPE_DOMAIN_TYPE (check_typedef (value_type (method_ptr))); |
685 | final_type = lookup_pointer_type (domain_type); | |
0d5de010 DJ |
686 | |
687 | method_type = TYPE_TARGET_TYPE (check_typedef (value_type (method_ptr))); | |
688 | ||
fead6908 | 689 | /* Extract the pointer to member. */ |
50810684 | 690 | gdbarch = get_type_arch (domain_type); |
ad4820ab | 691 | vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment); |
0d5de010 DJ |
692 | |
693 | /* First convert THIS to match the containing type of the pointer to | |
694 | member. This cast may adjust the value of THIS. */ | |
695 | *this_p = value_cast (final_type, *this_p); | |
696 | ||
697 | /* Then apply whatever adjustment is necessary. This creates a somewhat | |
698 | strange pointer: it claims to have type FINAL_TYPE, but in fact it | |
699 | might not be a valid FINAL_TYPE. For instance, it might be a | |
700 | base class of FINAL_TYPE. And if it's not the primary base class, | |
701 | then printing it out as a FINAL_TYPE object would produce some pretty | |
702 | garbage. | |
703 | ||
704 | But we don't really know the type of the first argument in | |
705 | METHOD_TYPE either, which is why this happens. We can't | |
706 | dereference this later as a FINAL_TYPE, but once we arrive in the | |
707 | called method we'll have debugging information for the type of | |
708 | "this" - and that'll match the value we produce here. | |
709 | ||
710 | You can provoke this case by casting a Base::* to a Derived::*, for | |
711 | instance. */ | |
ad4820ab | 712 | *this_p = value_cast (builtin_type (gdbarch)->builtin_data_ptr, *this_p); |
2497b498 | 713 | *this_p = value_ptradd (*this_p, adjustment); |
0d5de010 DJ |
714 | *this_p = value_cast (final_type, *this_p); |
715 | ||
716 | if (vbit) | |
717 | { | |
ad4820ab | 718 | LONGEST voffset; |
d8734c88 | 719 | |
ed09d7da | 720 | voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch)); |
ad4820ab UW |
721 | return gnuv3_get_virtual_fn (gdbarch, value_ind (*this_p), |
722 | method_type, voffset); | |
0d5de010 DJ |
723 | } |
724 | else | |
725 | return value_from_pointer (lookup_pointer_type (method_type), ptr_value); | |
726 | } | |
727 | ||
b18be20d DJ |
728 | /* Determine if we are currently in a C++ thunk. If so, get the address |
729 | of the routine we are thunking to and continue to there instead. */ | |
730 | ||
731 | static CORE_ADDR | |
52f729a7 | 732 | gnuv3_skip_trampoline (struct frame_info *frame, CORE_ADDR stop_pc) |
b18be20d DJ |
733 | { |
734 | CORE_ADDR real_stop_pc, method_stop_pc; | |
9970f04b | 735 | struct gdbarch *gdbarch = get_frame_arch (frame); |
b18be20d DJ |
736 | struct minimal_symbol *thunk_sym, *fn_sym; |
737 | struct obj_section *section; | |
0d5cff50 | 738 | const char *thunk_name, *fn_name; |
b18be20d | 739 | |
9970f04b | 740 | real_stop_pc = gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc); |
b18be20d DJ |
741 | if (real_stop_pc == 0) |
742 | real_stop_pc = stop_pc; | |
743 | ||
744 | /* Find the linker symbol for this potential thunk. */ | |
745 | thunk_sym = lookup_minimal_symbol_by_pc (real_stop_pc); | |
746 | section = find_pc_section (real_stop_pc); | |
747 | if (thunk_sym == NULL || section == NULL) | |
748 | return 0; | |
749 | ||
750 | /* The symbol's demangled name should be something like "virtual | |
751 | thunk to FUNCTION", where FUNCTION is the name of the function | |
752 | being thunked to. */ | |
753 | thunk_name = SYMBOL_DEMANGLED_NAME (thunk_sym); | |
754 | if (thunk_name == NULL || strstr (thunk_name, " thunk to ") == NULL) | |
755 | return 0; | |
756 | ||
757 | fn_name = strstr (thunk_name, " thunk to ") + strlen (" thunk to "); | |
758 | fn_sym = lookup_minimal_symbol (fn_name, NULL, section->objfile); | |
759 | if (fn_sym == NULL) | |
760 | return 0; | |
761 | ||
762 | method_stop_pc = SYMBOL_VALUE_ADDRESS (fn_sym); | |
e76f05fa | 763 | real_stop_pc = gdbarch_skip_trampoline_code |
9970f04b | 764 | (gdbarch, frame, method_stop_pc); |
b18be20d DJ |
765 | if (real_stop_pc == 0) |
766 | real_stop_pc = method_stop_pc; | |
767 | ||
768 | return real_stop_pc; | |
769 | } | |
770 | ||
41f1b697 DJ |
771 | /* Return nonzero if a type should be passed by reference. |
772 | ||
773 | The rule in the v3 ABI document comes from section 3.1.1. If the | |
774 | type has a non-trivial copy constructor or destructor, then the | |
775 | caller must make a copy (by calling the copy constructor if there | |
776 | is one or perform the copy itself otherwise), pass the address of | |
777 | the copy, and then destroy the temporary (if necessary). | |
778 | ||
779 | For return values with non-trivial copy constructors or | |
780 | destructors, space will be allocated in the caller, and a pointer | |
781 | will be passed as the first argument (preceding "this"). | |
782 | ||
783 | We don't have a bulletproof mechanism for determining whether a | |
784 | constructor or destructor is trivial. For GCC and DWARF2 debug | |
785 | information, we can check the artificial flag. | |
786 | ||
787 | We don't do anything with the constructors or destructors, | |
788 | but we have to get the argument passing right anyway. */ | |
789 | static int | |
790 | gnuv3_pass_by_reference (struct type *type) | |
791 | { | |
792 | int fieldnum, fieldelem; | |
793 | ||
794 | CHECK_TYPEDEF (type); | |
795 | ||
796 | /* We're only interested in things that can have methods. */ | |
797 | if (TYPE_CODE (type) != TYPE_CODE_STRUCT | |
798 | && TYPE_CODE (type) != TYPE_CODE_CLASS | |
799 | && TYPE_CODE (type) != TYPE_CODE_UNION) | |
800 | return 0; | |
801 | ||
802 | for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++) | |
803 | for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum); | |
804 | fieldelem++) | |
805 | { | |
806 | struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, fieldnum); | |
0d5cff50 | 807 | const char *name = TYPE_FN_FIELDLIST_NAME (type, fieldnum); |
41f1b697 DJ |
808 | struct type *fieldtype = TYPE_FN_FIELD_TYPE (fn, fieldelem); |
809 | ||
810 | /* If this function is marked as artificial, it is compiler-generated, | |
811 | and we assume it is trivial. */ | |
812 | if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem)) | |
813 | continue; | |
814 | ||
815 | /* If we've found a destructor, we must pass this by reference. */ | |
816 | if (name[0] == '~') | |
817 | return 1; | |
818 | ||
819 | /* If the mangled name of this method doesn't indicate that it | |
820 | is a constructor, we're not interested. | |
821 | ||
822 | FIXME drow/2007-09-23: We could do this using the name of | |
823 | the method and the name of the class instead of dealing | |
824 | with the mangled name. We don't have a convenient function | |
825 | to strip off both leading scope qualifiers and trailing | |
826 | template arguments yet. */ | |
827 | if (!is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem))) | |
828 | continue; | |
829 | ||
830 | /* If this method takes two arguments, and the second argument is | |
831 | a reference to this class, then it is a copy constructor. */ | |
832 | if (TYPE_NFIELDS (fieldtype) == 2 | |
833 | && TYPE_CODE (TYPE_FIELD_TYPE (fieldtype, 1)) == TYPE_CODE_REF | |
0963b4bd MS |
834 | && check_typedef (TYPE_TARGET_TYPE (TYPE_FIELD_TYPE (fieldtype, |
835 | 1))) == type) | |
41f1b697 DJ |
836 | return 1; |
837 | } | |
838 | ||
839 | /* Even if all the constructors and destructors were artificial, one | |
840 | of them may have invoked a non-artificial constructor or | |
841 | destructor in a base class. If any base class needs to be passed | |
842 | by reference, so does this class. Similarly for members, which | |
843 | are constructed whenever this class is. We do not need to worry | |
844 | about recursive loops here, since we are only looking at members | |
bceffbf3 | 845 | of complete class type. Also ignore any static members. */ |
41f1b697 | 846 | for (fieldnum = 0; fieldnum < TYPE_NFIELDS (type); fieldnum++) |
bceffbf3 JK |
847 | if (! field_is_static (&TYPE_FIELD (type, fieldnum)) |
848 | && gnuv3_pass_by_reference (TYPE_FIELD_TYPE (type, fieldnum))) | |
41f1b697 DJ |
849 | return 1; |
850 | ||
851 | return 0; | |
852 | } | |
853 | ||
7ed49443 JB |
854 | static void |
855 | init_gnuv3_ops (void) | |
856 | { | |
0963b4bd MS |
857 | vtable_type_gdbarch_data |
858 | = gdbarch_data_register_post_init (build_gdb_vtable_type); | |
7ed49443 JB |
859 | |
860 | gnu_v3_abi_ops.shortname = "gnu-v3"; | |
861 | gnu_v3_abi_ops.longname = "GNU G++ Version 3 ABI"; | |
862 | gnu_v3_abi_ops.doc = "G++ Version 3 ABI"; | |
358777b0 EZ |
863 | gnu_v3_abi_ops.is_destructor_name = |
864 | (enum dtor_kinds (*) (const char *))is_gnu_v3_mangled_dtor; | |
865 | gnu_v3_abi_ops.is_constructor_name = | |
866 | (enum ctor_kinds (*) (const char *))is_gnu_v3_mangled_ctor; | |
7ed49443 JB |
867 | gnu_v3_abi_ops.is_vtable_name = gnuv3_is_vtable_name; |
868 | gnu_v3_abi_ops.is_operator_name = gnuv3_is_operator_name; | |
869 | gnu_v3_abi_ops.rtti_type = gnuv3_rtti_type; | |
870 | gnu_v3_abi_ops.virtual_fn_field = gnuv3_virtual_fn_field; | |
1514d34e | 871 | gnu_v3_abi_ops.baseclass_offset = gnuv3_baseclass_offset; |
0d5de010 DJ |
872 | gnu_v3_abi_ops.print_method_ptr = gnuv3_print_method_ptr; |
873 | gnu_v3_abi_ops.method_ptr_size = gnuv3_method_ptr_size; | |
874 | gnu_v3_abi_ops.make_method_ptr = gnuv3_make_method_ptr; | |
875 | gnu_v3_abi_ops.method_ptr_to_value = gnuv3_method_ptr_to_value; | |
b18be20d | 876 | gnu_v3_abi_ops.skip_trampoline = gnuv3_skip_trampoline; |
41f1b697 | 877 | gnu_v3_abi_ops.pass_by_reference = gnuv3_pass_by_reference; |
7ed49443 JB |
878 | } |
879 | ||
b9362cc7 | 880 | extern initialize_file_ftype _initialize_gnu_v3_abi; /* -Wmissing-prototypes */ |
7ed49443 JB |
881 | |
882 | void | |
883 | _initialize_gnu_v3_abi (void) | |
884 | { | |
885 | init_gnuv3_ops (); | |
886 | ||
fe1f4a5e | 887 | register_cp_abi (&gnu_v3_abi_ops); |
7ed49443 | 888 | } |