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015a42b4 | 1 | /* Abstraction of GNU v2 abi. |
1bac305b | 2 | |
4c38e0a4 | 3 | Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010 |
9b254dd1 | 4 | Free Software Foundation, Inc. |
1bac305b | 5 | |
015a42b4 | 6 | Contributed by Daniel Berlin <dberlin@redhat.com> |
015a42b4 JB |
7 | |
8 | This file is part of GDB. | |
9 | ||
a9762ec7 JB |
10 | This program is free software; you can redistribute it and/or modify |
11 | it under the terms of the GNU General Public License as published by | |
12 | the Free Software Foundation; either version 3 of the License, or | |
015a42b4 JB |
13 | (at your option) any later version. |
14 | ||
15 | This program is distributed in the hope that it will be useful, | |
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | GNU General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 21 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
015a42b4 JB |
22 | |
23 | #include "defs.h" | |
015a42b4 JB |
24 | #include "gdb_string.h" |
25 | #include "symtab.h" | |
26 | #include "gdbtypes.h" | |
27 | #include "value.h" | |
28 | #include "demangle.h" | |
29 | #include "cp-abi.h" | |
362ff856 | 30 | #include "cp-support.h" |
015a42b4 JB |
31 | |
32 | #include <ctype.h> | |
33 | ||
34 | struct cp_abi_ops gnu_v2_abi_ops; | |
35 | ||
36 | static int vb_match (struct type *, int, struct type *); | |
37 | ||
38 | static enum dtor_kinds | |
39 | gnuv2_is_destructor_name (const char *name) | |
40 | { | |
41 | if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_') | |
42 | || strncmp (name, "__dt__", 6) == 0) | |
43 | return complete_object_dtor; | |
44 | else | |
45 | return 0; | |
46 | } | |
47 | ||
48 | static enum ctor_kinds | |
49 | gnuv2_is_constructor_name (const char *name) | |
50 | { | |
51 | if ((name[0] == '_' && name[1] == '_' | |
52 | && (isdigit (name[2]) || strchr ("Qt", name[2]))) | |
53 | || strncmp (name, "__ct__", 6) == 0) | |
54 | return complete_object_ctor; | |
55 | else | |
56 | return 0; | |
57 | } | |
58 | ||
59 | static int | |
60 | gnuv2_is_vtable_name (const char *name) | |
61 | { | |
62 | return (((name)[0] == '_' | |
63 | && (((name)[1] == 'V' && (name)[2] == 'T') | |
64 | || ((name)[1] == 'v' && (name)[2] == 't')) | |
65 | && is_cplus_marker ((name)[3])) || | |
66 | ((name)[0] == '_' && (name)[1] == '_' | |
67 | && (name)[2] == 'v' && (name)[3] == 't' && (name)[4] == '_')); | |
68 | } | |
69 | ||
70 | static int | |
71 | gnuv2_is_operator_name (const char *name) | |
72 | { | |
73 | return strncmp (name, "operator", 8) == 0; | |
74 | } | |
75 | ||
76 | \f | |
77 | /* Return a virtual function as a value. | |
78 | ARG1 is the object which provides the virtual function | |
79 | table pointer. *ARG1P is side-effected in calling this function. | |
80 | F is the list of member functions which contains the desired virtual | |
81 | function. | |
82 | J is an index into F which provides the desired virtual function. | |
83 | ||
84 | TYPE is the type in which F is located. */ | |
e933e538 AC |
85 | static struct value * |
86 | gnuv2_virtual_fn_field (struct value **arg1p, struct fn_field * f, int j, | |
015a42b4 JB |
87 | struct type * type, int offset) |
88 | { | |
e933e538 | 89 | struct value *arg1 = *arg1p; |
df407dfe | 90 | struct type *type1 = check_typedef (value_type (arg1)); |
015a42b4 JB |
91 | struct type *entry_type; |
92 | /* First, get the virtual function table pointer. That comes | |
93 | with a strange type, so cast it to type `pointer to long' (which | |
94 | should serve just fine as a function type). Then, index into | |
95 | the table, and convert final value to appropriate function type. */ | |
e933e538 AC |
96 | struct value *entry; |
97 | struct value *vfn; | |
98 | struct value *vtbl; | |
2497b498 | 99 | LONGEST vi = (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j); |
015a42b4 JB |
100 | struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j); |
101 | struct type *context; | |
81fe8080 DE |
102 | struct type *context_vptr_basetype; |
103 | int context_vptr_fieldno; | |
104 | ||
015a42b4 JB |
105 | if (fcontext == NULL) |
106 | /* We don't have an fcontext (e.g. the program was compiled with | |
107 | g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE. | |
108 | This won't work right for multiple inheritance, but at least we | |
109 | should do as well as GDB 3.x did. */ | |
110 | fcontext = TYPE_VPTR_BASETYPE (type); | |
111 | context = lookup_pointer_type (fcontext); | |
112 | /* Now context is a pointer to the basetype containing the vtbl. */ | |
113 | if (TYPE_TARGET_TYPE (context) != type1) | |
114 | { | |
e933e538 | 115 | struct value *tmp = value_cast (context, value_addr (arg1)); |
015a42b4 | 116 | arg1 = value_ind (tmp); |
df407dfe | 117 | type1 = check_typedef (value_type (arg1)); |
015a42b4 JB |
118 | } |
119 | ||
120 | context = type1; | |
121 | /* Now context is the basetype containing the vtbl. */ | |
122 | ||
123 | /* This type may have been defined before its virtual function table | |
124 | was. If so, fill in the virtual function table entry for the | |
125 | type now. */ | |
81fe8080 DE |
126 | context_vptr_fieldno = get_vptr_fieldno (context, &context_vptr_basetype); |
127 | /* FIXME: What to do if vptr_fieldno is still -1? */ | |
015a42b4 JB |
128 | |
129 | /* The virtual function table is now an array of structures | |
130 | which have the form { int16 offset, delta; void *pfn; }. */ | |
81fe8080 DE |
131 | vtbl = value_primitive_field (arg1, 0, context_vptr_fieldno, |
132 | context_vptr_basetype); | |
015a42b4 JB |
133 | |
134 | /* With older versions of g++, the vtbl field pointed to an array | |
135 | of structures. Nowadays it points directly to the structure. */ | |
df407dfe AC |
136 | if (TYPE_CODE (value_type (vtbl)) == TYPE_CODE_PTR |
137 | && TYPE_CODE (TYPE_TARGET_TYPE (value_type (vtbl))) == TYPE_CODE_ARRAY) | |
015a42b4 JB |
138 | { |
139 | /* Handle the case where the vtbl field points to an | |
140 | array of structures. */ | |
141 | vtbl = value_ind (vtbl); | |
142 | ||
143 | /* Index into the virtual function table. This is hard-coded because | |
144 | looking up a field is not cheap, and it may be important to save | |
145 | time, e.g. if the user has set a conditional breakpoint calling | |
146 | a virtual function. */ | |
147 | entry = value_subscript (vtbl, vi); | |
148 | } | |
149 | else | |
150 | { | |
151 | /* Handle the case where the vtbl field points directly to a structure. */ | |
89eef114 | 152 | vtbl = value_ptradd (vtbl, vi); |
015a42b4 JB |
153 | entry = value_ind (vtbl); |
154 | } | |
155 | ||
df407dfe | 156 | entry_type = check_typedef (value_type (entry)); |
015a42b4 JB |
157 | |
158 | if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT) | |
159 | { | |
160 | /* Move the `this' pointer according to the virtual function table. */ | |
f5cf64a7 | 161 | set_value_offset (arg1, value_offset (arg1) + value_as_long (value_field (entry, 0))); |
015a42b4 | 162 | |
d69fe07e | 163 | if (!value_lazy (arg1)) |
015a42b4 | 164 | { |
dfa52d88 | 165 | set_value_lazy (arg1, 1); |
015a42b4 JB |
166 | value_fetch_lazy (arg1); |
167 | } | |
168 | ||
169 | vfn = value_field (entry, 2); | |
170 | } | |
171 | else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR) | |
172 | vfn = entry; | |
173 | else | |
8a3fe4f8 | 174 | error (_("I'm confused: virtual function table has bad type")); |
015a42b4 | 175 | /* Reinstantiate the function pointer with the correct type. */ |
04624583 | 176 | deprecated_set_value_type (vfn, lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j))); |
015a42b4 JB |
177 | |
178 | *arg1p = arg1; | |
179 | return vfn; | |
180 | } | |
181 | ||
182 | ||
b9362cc7 | 183 | static struct type * |
e933e538 | 184 | gnuv2_value_rtti_type (struct value *v, int *full, int *top, int *using_enc) |
015a42b4 JB |
185 | { |
186 | struct type *known_type; | |
187 | struct type *rtti_type; | |
188 | CORE_ADDR coreptr; | |
e933e538 | 189 | struct value *vp; |
015a42b4 JB |
190 | long top_offset = 0; |
191 | char rtti_type_name[256]; | |
192 | CORE_ADDR vtbl; | |
193 | struct minimal_symbol *minsym; | |
194 | struct symbol *sym; | |
7d63ec12 | 195 | char *demangled_name, *p; |
015a42b4 | 196 | struct type *btype; |
81fe8080 DE |
197 | struct type *known_type_vptr_basetype; |
198 | int known_type_vptr_fieldno; | |
015a42b4 JB |
199 | |
200 | if (full) | |
201 | *full = 0; | |
202 | if (top) | |
203 | *top = -1; | |
204 | if (using_enc) | |
205 | *using_enc = 0; | |
206 | ||
207 | /* Get declared type */ | |
df407dfe | 208 | known_type = value_type (v); |
015a42b4 JB |
209 | CHECK_TYPEDEF (known_type); |
210 | /* RTTI works only or class objects */ | |
211 | if (TYPE_CODE (known_type) != TYPE_CODE_CLASS) | |
212 | return NULL; | |
213 | ||
214 | /* Plan on this changing in the future as i get around to setting | |
215 | the vtables properly for G++ compiled stuff. Also, I'll be using | |
216 | the type info functions, which are always right. Deal with it | |
217 | until then. */ | |
218 | ||
81fe8080 DE |
219 | /* Try to get the vptr basetype, fieldno. */ |
220 | known_type_vptr_fieldno = get_vptr_fieldno (known_type, | |
221 | &known_type_vptr_basetype); | |
015a42b4 | 222 | |
81fe8080 DE |
223 | /* If we can't find it, give up. */ |
224 | if (known_type_vptr_fieldno < 0) | |
015a42b4 JB |
225 | return NULL; |
226 | ||
227 | /* Make sure our basetype and known type match, otherwise, cast | |
228 | so we can get at the vtable properly. | |
229 | */ | |
81fe8080 | 230 | btype = known_type_vptr_basetype; |
015a42b4 JB |
231 | CHECK_TYPEDEF (btype); |
232 | if (btype != known_type ) | |
233 | { | |
234 | v = value_cast (btype, v); | |
235 | if (using_enc) | |
236 | *using_enc=1; | |
237 | } | |
238 | /* | |
239 | We can't use value_ind here, because it would want to use RTTI, and | |
240 | we'd waste a bunch of time figuring out we already know the type. | |
241 | Besides, we don't care about the type, just the actual pointer | |
242 | */ | |
42ae5230 | 243 | if (value_address (value_field (v, known_type_vptr_fieldno)) == 0) |
015a42b4 JB |
244 | return NULL; |
245 | ||
81fe8080 | 246 | vtbl = value_as_address (value_field (v, known_type_vptr_fieldno)); |
015a42b4 JB |
247 | |
248 | /* Try to find a symbol that is the vtable */ | |
249 | minsym=lookup_minimal_symbol_by_pc(vtbl); | |
250 | if (minsym==NULL | |
3567439c | 251 | || (demangled_name=SYMBOL_LINKAGE_NAME (minsym))==NULL |
015a42b4 JB |
252 | || !is_vtable_name (demangled_name)) |
253 | return NULL; | |
254 | ||
255 | /* If we just skip the prefix, we get screwed by namespaces */ | |
256 | demangled_name=cplus_demangle(demangled_name,DMGL_PARAMS|DMGL_ANSI); | |
7d63ec12 MS |
257 | p = strchr (demangled_name, ' '); |
258 | if (p) | |
259 | *p = '\0'; | |
015a42b4 JB |
260 | |
261 | /* Lookup the type for the name */ | |
362ff856 MC |
262 | /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */ |
263 | rtti_type = cp_lookup_rtti_type (demangled_name, NULL); | |
264 | if (rtti_type == NULL) | |
015a42b4 JB |
265 | return NULL; |
266 | ||
267 | if (TYPE_N_BASECLASSES(rtti_type) > 1 && full && (*full) != 1) | |
268 | { | |
269 | if (top) | |
270 | *top=TYPE_BASECLASS_BITPOS(rtti_type,TYPE_VPTR_FIELDNO(rtti_type))/8; | |
271 | if (top && ((*top) >0)) | |
272 | { | |
273 | if (TYPE_LENGTH(rtti_type) > TYPE_LENGTH(known_type)) | |
274 | { | |
275 | if (full) | |
276 | *full=0; | |
277 | } | |
278 | else | |
279 | { | |
280 | if (full) | |
281 | *full=1; | |
282 | } | |
283 | } | |
284 | } | |
285 | else | |
286 | { | |
287 | if (full) | |
288 | *full=1; | |
289 | } | |
015a42b4 JB |
290 | |
291 | return rtti_type; | |
292 | } | |
293 | ||
1514d34e DJ |
294 | /* Return true if the INDEXth field of TYPE is a virtual baseclass |
295 | pointer which is for the base class whose type is BASECLASS. */ | |
296 | ||
297 | static int | |
298 | vb_match (struct type *type, int index, struct type *basetype) | |
299 | { | |
300 | struct type *fieldtype; | |
301 | char *name = TYPE_FIELD_NAME (type, index); | |
302 | char *field_class_name = NULL; | |
303 | ||
304 | if (*name != '_') | |
305 | return 0; | |
306 | /* gcc 2.4 uses _vb$. */ | |
307 | if (name[1] == 'v' && name[2] == 'b' && is_cplus_marker (name[3])) | |
308 | field_class_name = name + 4; | |
309 | /* gcc 2.5 will use __vb_. */ | |
310 | if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_') | |
311 | field_class_name = name + 5; | |
312 | ||
313 | if (field_class_name == NULL) | |
314 | /* This field is not a virtual base class pointer. */ | |
315 | return 0; | |
316 | ||
317 | /* It's a virtual baseclass pointer, now we just need to find out whether | |
318 | it is for this baseclass. */ | |
319 | fieldtype = TYPE_FIELD_TYPE (type, index); | |
320 | if (fieldtype == NULL | |
321 | || TYPE_CODE (fieldtype) != TYPE_CODE_PTR) | |
322 | /* "Can't happen". */ | |
323 | return 0; | |
324 | ||
325 | /* What we check for is that either the types are equal (needed for | |
326 | nameless types) or have the same name. This is ugly, and a more | |
327 | elegant solution should be devised (which would probably just push | |
328 | the ugliness into symbol reading unless we change the stabs format). */ | |
329 | if (TYPE_TARGET_TYPE (fieldtype) == basetype) | |
330 | return 1; | |
331 | ||
332 | if (TYPE_NAME (basetype) != NULL | |
333 | && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL | |
bde58177 AC |
334 | && strcmp (TYPE_NAME (basetype), |
335 | TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))) == 0) | |
1514d34e DJ |
336 | return 1; |
337 | return 0; | |
338 | } | |
339 | ||
340 | /* Compute the offset of the baseclass which is | |
341 | the INDEXth baseclass of class TYPE, | |
342 | for value at VALADDR (in host) at ADDRESS (in target). | |
343 | The result is the offset of the baseclass value relative | |
344 | to (the address of)(ARG) + OFFSET. | |
345 | ||
346 | -1 is returned on error. */ | |
347 | ||
f23f4c59 | 348 | static int |
06c4d4dc AC |
349 | gnuv2_baseclass_offset (struct type *type, int index, |
350 | const bfd_byte *valaddr, CORE_ADDR address) | |
1514d34e DJ |
351 | { |
352 | struct type *basetype = TYPE_BASECLASS (type, index); | |
353 | ||
354 | if (BASETYPE_VIA_VIRTUAL (type, index)) | |
355 | { | |
356 | /* Must hunt for the pointer to this virtual baseclass. */ | |
aa1ee363 AC |
357 | int i, len = TYPE_NFIELDS (type); |
358 | int n_baseclasses = TYPE_N_BASECLASSES (type); | |
1514d34e DJ |
359 | |
360 | /* First look for the virtual baseclass pointer | |
361 | in the fields. */ | |
362 | for (i = n_baseclasses; i < len; i++) | |
363 | { | |
364 | if (vb_match (type, i, basetype)) | |
365 | { | |
366 | CORE_ADDR addr | |
367 | = unpack_pointer (TYPE_FIELD_TYPE (type, i), | |
368 | valaddr + (TYPE_FIELD_BITPOS (type, i) / 8)); | |
369 | ||
370 | return addr - (LONGEST) address; | |
371 | } | |
372 | } | |
373 | /* Not in the fields, so try looking through the baseclasses. */ | |
374 | for (i = index + 1; i < n_baseclasses; i++) | |
375 | { | |
376 | int boffset = | |
377 | baseclass_offset (type, i, valaddr, address); | |
378 | if (boffset) | |
379 | return boffset; | |
380 | } | |
381 | /* Not found. */ | |
382 | return -1; | |
383 | } | |
384 | ||
385 | /* Baseclass is easily computed. */ | |
386 | return TYPE_BASECLASS_BITPOS (type, index) / 8; | |
387 | } | |
015a42b4 JB |
388 | |
389 | static void | |
390 | init_gnuv2_ops (void) | |
391 | { | |
392 | gnu_v2_abi_ops.shortname = "gnu-v2"; | |
393 | gnu_v2_abi_ops.longname = "GNU G++ Version 2 ABI"; | |
394 | gnu_v2_abi_ops.doc = "G++ Version 2 ABI"; | |
395 | gnu_v2_abi_ops.is_destructor_name = gnuv2_is_destructor_name; | |
396 | gnu_v2_abi_ops.is_constructor_name = gnuv2_is_constructor_name; | |
397 | gnu_v2_abi_ops.is_vtable_name = gnuv2_is_vtable_name; | |
398 | gnu_v2_abi_ops.is_operator_name = gnuv2_is_operator_name; | |
399 | gnu_v2_abi_ops.virtual_fn_field = gnuv2_virtual_fn_field; | |
400 | gnu_v2_abi_ops.rtti_type = gnuv2_value_rtti_type; | |
1514d34e | 401 | gnu_v2_abi_ops.baseclass_offset = gnuv2_baseclass_offset; |
015a42b4 JB |
402 | } |
403 | ||
b9362cc7 AC |
404 | extern initialize_file_ftype _initialize_gnu_v2_abi; /* -Wmissing-prototypes */ |
405 | ||
015a42b4 JB |
406 | void |
407 | _initialize_gnu_v2_abi (void) | |
408 | { | |
409 | init_gnuv2_ops (); | |
fe1f4a5e DJ |
410 | register_cp_abi (&gnu_v2_abi_ops); |
411 | set_cp_abi_as_auto_default (gnu_v2_abi_ops.shortname); | |
015a42b4 | 412 | } |