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015a42b4 | 1 | /* Abstraction of GNU v2 abi. |
1bac305b | 2 | |
1d506c26 | 3 | Copyright (C) 2001-2024 Free Software Foundation, Inc. |
1bac305b | 4 | |
015a42b4 | 5 | Contributed by Daniel Berlin <dberlin@redhat.com> |
015a42b4 JB |
6 | |
7 | This file is part of GDB. | |
8 | ||
a9762ec7 JB |
9 | This program is free software; you can redistribute it and/or modify |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3 of the License, or | |
015a42b4 JB |
12 | (at your option) any later version. |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
015a42b4 JB |
21 | |
22 | #include "defs.h" | |
015a42b4 JB |
23 | #include "symtab.h" |
24 | #include "gdbtypes.h" | |
25 | #include "value.h" | |
26 | #include "demangle.h" | |
50f182aa | 27 | #include "gdb-demangle.h" |
015a42b4 | 28 | #include "cp-abi.h" |
362ff856 | 29 | #include "cp-support.h" |
015a42b4 JB |
30 | #include <ctype.h> |
31 | ||
6bd434d6 | 32 | static cp_abi_ops gnu_v2_abi_ops; |
015a42b4 JB |
33 | |
34 | static int vb_match (struct type *, int, struct type *); | |
35 | ||
36 | static enum dtor_kinds | |
37 | gnuv2_is_destructor_name (const char *name) | |
38 | { | |
39 | if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_') | |
61012eef | 40 | || startswith (name, "__dt__")) |
015a42b4 JB |
41 | return complete_object_dtor; |
42 | else | |
ebf05345 | 43 | return (enum dtor_kinds) 0; |
015a42b4 JB |
44 | } |
45 | ||
46 | static enum ctor_kinds | |
47 | gnuv2_is_constructor_name (const char *name) | |
48 | { | |
49 | if ((name[0] == '_' && name[1] == '_' | |
50 | && (isdigit (name[2]) || strchr ("Qt", name[2]))) | |
61012eef | 51 | || startswith (name, "__ct__")) |
015a42b4 JB |
52 | return complete_object_ctor; |
53 | else | |
ebf05345 | 54 | return (enum ctor_kinds) 0; |
015a42b4 JB |
55 | } |
56 | ||
57 | static int | |
58 | gnuv2_is_vtable_name (const char *name) | |
59 | { | |
60 | return (((name)[0] == '_' | |
61 | && (((name)[1] == 'V' && (name)[2] == 'T') | |
62 | || ((name)[1] == 'v' && (name)[2] == 't')) | |
63 | && is_cplus_marker ((name)[3])) || | |
64 | ((name)[0] == '_' && (name)[1] == '_' | |
65 | && (name)[2] == 'v' && (name)[3] == 't' && (name)[4] == '_')); | |
66 | } | |
67 | ||
68 | static int | |
69 | gnuv2_is_operator_name (const char *name) | |
70 | { | |
8090b426 | 71 | return startswith (name, CP_OPERATOR_STR); |
015a42b4 JB |
72 | } |
73 | ||
74 | \f | |
75 | /* Return a virtual function as a value. | |
76 | ARG1 is the object which provides the virtual function | |
77 | table pointer. *ARG1P is side-effected in calling this function. | |
78 | F is the list of member functions which contains the desired virtual | |
79 | function. | |
80 | J is an index into F which provides the desired virtual function. | |
81 | ||
82 | TYPE is the type in which F is located. */ | |
e933e538 AC |
83 | static struct value * |
84 | gnuv2_virtual_fn_field (struct value **arg1p, struct fn_field * f, int j, | |
015a42b4 JB |
85 | struct type * type, int offset) |
86 | { | |
e933e538 | 87 | struct value *arg1 = *arg1p; |
d0c97917 | 88 | struct type *type1 = check_typedef (arg1->type ()); |
015a42b4 JB |
89 | struct type *entry_type; |
90 | /* First, get the virtual function table pointer. That comes | |
91 | with a strange type, so cast it to type `pointer to long' (which | |
92 | should serve just fine as a function type). Then, index into | |
93 | the table, and convert final value to appropriate function type. */ | |
e933e538 AC |
94 | struct value *entry; |
95 | struct value *vfn; | |
96 | struct value *vtbl; | |
2497b498 | 97 | LONGEST vi = (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j); |
015a42b4 JB |
98 | struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j); |
99 | struct type *context; | |
81fe8080 DE |
100 | struct type *context_vptr_basetype; |
101 | int context_vptr_fieldno; | |
102 | ||
015a42b4 JB |
103 | if (fcontext == NULL) |
104 | /* We don't have an fcontext (e.g. the program was compiled with | |
105 | g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE. | |
106 | This won't work right for multiple inheritance, but at least we | |
107 | should do as well as GDB 3.x did. */ | |
108 | fcontext = TYPE_VPTR_BASETYPE (type); | |
109 | context = lookup_pointer_type (fcontext); | |
110 | /* Now context is a pointer to the basetype containing the vtbl. */ | |
27710edb | 111 | if (context->target_type () != type1) |
015a42b4 | 112 | { |
e933e538 | 113 | struct value *tmp = value_cast (context, value_addr (arg1)); |
d8734c88 | 114 | |
015a42b4 | 115 | arg1 = value_ind (tmp); |
d0c97917 | 116 | type1 = check_typedef (arg1->type ()); |
015a42b4 JB |
117 | } |
118 | ||
119 | context = type1; | |
120 | /* Now context is the basetype containing the vtbl. */ | |
121 | ||
122 | /* This type may have been defined before its virtual function table | |
123 | was. If so, fill in the virtual function table entry for the | |
124 | type now. */ | |
81fe8080 DE |
125 | context_vptr_fieldno = get_vptr_fieldno (context, &context_vptr_basetype); |
126 | /* FIXME: What to do if vptr_fieldno is still -1? */ | |
015a42b4 JB |
127 | |
128 | /* The virtual function table is now an array of structures | |
129 | which have the form { int16 offset, delta; void *pfn; }. */ | |
6c49729e | 130 | vtbl = arg1->primitive_field (0, context_vptr_fieldno, |
81fe8080 | 131 | context_vptr_basetype); |
015a42b4 JB |
132 | |
133 | /* With older versions of g++, the vtbl field pointed to an array | |
0963b4bd | 134 | of structures. Nowadays it points directly to the structure. */ |
d0c97917 TT |
135 | if (vtbl->type ()->code () == TYPE_CODE_PTR |
136 | && vtbl->type ()->target_type ()->code () == TYPE_CODE_ARRAY) | |
015a42b4 JB |
137 | { |
138 | /* Handle the case where the vtbl field points to an | |
dda83cd7 | 139 | array of structures. */ |
015a42b4 JB |
140 | vtbl = value_ind (vtbl); |
141 | ||
142 | /* Index into the virtual function table. This is hard-coded because | |
dda83cd7 SM |
143 | looking up a field is not cheap, and it may be important to save |
144 | time, e.g. if the user has set a conditional breakpoint calling | |
145 | a virtual function. */ | |
015a42b4 JB |
146 | entry = value_subscript (vtbl, vi); |
147 | } | |
148 | else | |
149 | { | |
0963b4bd MS |
150 | /* Handle the case where the vtbl field points directly to a |
151 | structure. */ | |
89eef114 | 152 | vtbl = value_ptradd (vtbl, vi); |
015a42b4 JB |
153 | entry = value_ind (vtbl); |
154 | } | |
155 | ||
d0c97917 | 156 | entry_type = check_typedef (entry->type ()); |
015a42b4 | 157 | |
78134374 | 158 | if (entry_type->code () == TYPE_CODE_STRUCT) |
015a42b4 | 159 | { |
0963b4bd | 160 | /* Move the `this' pointer according to the virtual function table. */ |
76675c4d | 161 | arg1->set_offset (arg1->offset () |
0963b4bd | 162 | + value_as_long (value_field (entry, 0))); |
015a42b4 | 163 | |
3ee3b270 | 164 | if (!arg1->lazy ()) |
015a42b4 | 165 | { |
a5b210cb | 166 | arg1->set_lazy (true); |
78259c36 | 167 | arg1->fetch_lazy (); |
015a42b4 JB |
168 | } |
169 | ||
170 | vfn = value_field (entry, 2); | |
171 | } | |
78134374 | 172 | else if (entry_type->code () == TYPE_CODE_PTR) |
015a42b4 JB |
173 | vfn = entry; |
174 | else | |
8a3fe4f8 | 175 | error (_("I'm confused: virtual function table has bad type")); |
015a42b4 | 176 | /* Reinstantiate the function pointer with the correct type. */ |
81ae560c | 177 | vfn->deprecated_set_type (lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j))); |
015a42b4 JB |
178 | |
179 | *arg1p = arg1; | |
180 | return vfn; | |
181 | } | |
182 | ||
183 | ||
b9362cc7 | 184 | static struct type * |
6b850546 | 185 | gnuv2_value_rtti_type (struct value *v, int *full, LONGEST *top, int *using_enc) |
015a42b4 JB |
186 | { |
187 | struct type *known_type; | |
188 | struct type *rtti_type; | |
015a42b4 | 189 | CORE_ADDR vtbl; |
7cbd4a93 | 190 | struct bound_minimal_symbol minsym; |
3456e70c | 191 | char *p; |
0d5cff50 | 192 | const char *linkage_name; |
015a42b4 | 193 | struct type *btype; |
81fe8080 DE |
194 | struct type *known_type_vptr_basetype; |
195 | int known_type_vptr_fieldno; | |
015a42b4 JB |
196 | |
197 | if (full) | |
198 | *full = 0; | |
199 | if (top) | |
200 | *top = -1; | |
201 | if (using_enc) | |
202 | *using_enc = 0; | |
203 | ||
0963b4bd | 204 | /* Get declared type. */ |
d0c97917 | 205 | known_type = v->type (); |
f168693b | 206 | known_type = check_typedef (known_type); |
0963b4bd | 207 | /* RTTI works only or class objects. */ |
78134374 | 208 | if (known_type->code () != TYPE_CODE_STRUCT) |
015a42b4 JB |
209 | return NULL; |
210 | ||
211 | /* Plan on this changing in the future as i get around to setting | |
212 | the vtables properly for G++ compiled stuff. Also, I'll be using | |
213 | the type info functions, which are always right. Deal with it | |
214 | until then. */ | |
215 | ||
81fe8080 DE |
216 | /* Try to get the vptr basetype, fieldno. */ |
217 | known_type_vptr_fieldno = get_vptr_fieldno (known_type, | |
218 | &known_type_vptr_basetype); | |
015a42b4 | 219 | |
81fe8080 DE |
220 | /* If we can't find it, give up. */ |
221 | if (known_type_vptr_fieldno < 0) | |
015a42b4 JB |
222 | return NULL; |
223 | ||
224 | /* Make sure our basetype and known type match, otherwise, cast | |
0963b4bd | 225 | so we can get at the vtable properly. */ |
81fe8080 | 226 | btype = known_type_vptr_basetype; |
f168693b | 227 | btype = check_typedef (btype); |
015a42b4 JB |
228 | if (btype != known_type ) |
229 | { | |
230 | v = value_cast (btype, v); | |
231 | if (using_enc) | |
dda83cd7 | 232 | *using_enc=1; |
015a42b4 | 233 | } |
0963b4bd MS |
234 | /* We can't use value_ind here, because it would want to use RTTI, and |
235 | we'd waste a bunch of time figuring out we already know the type. | |
236 | Besides, we don't care about the type, just the actual pointer. */ | |
9feb2d07 | 237 | if (value_field (v, known_type_vptr_fieldno)->address () == 0) |
015a42b4 JB |
238 | return NULL; |
239 | ||
81fe8080 | 240 | vtbl = value_as_address (value_field (v, known_type_vptr_fieldno)); |
015a42b4 | 241 | |
0963b4bd | 242 | /* Try to find a symbol that is the vtable. */ |
015a42b4 | 243 | minsym=lookup_minimal_symbol_by_pc(vtbl); |
7cbd4a93 | 244 | if (minsym.minsym==NULL |
c9d95fa3 | 245 | || (linkage_name=minsym.minsym->linkage_name ())==NULL |
0d5cff50 | 246 | || !is_vtable_name (linkage_name)) |
015a42b4 JB |
247 | return NULL; |
248 | ||
0963b4bd | 249 | /* If we just skip the prefix, we get screwed by namespaces. */ |
3456e70c TT |
250 | gdb::unique_xmalloc_ptr<char> demangled_name |
251 | = gdb_demangle(linkage_name,DMGL_PARAMS|DMGL_ANSI); | |
252 | p = strchr (demangled_name.get (), ' '); | |
7d63ec12 MS |
253 | if (p) |
254 | *p = '\0'; | |
015a42b4 | 255 | |
0963b4bd MS |
256 | /* Lookup the type for the name. */ |
257 | /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */ | |
3456e70c | 258 | rtti_type = cp_lookup_rtti_type (demangled_name.get (), NULL); |
362ff856 | 259 | if (rtti_type == NULL) |
015a42b4 JB |
260 | return NULL; |
261 | ||
262 | if (TYPE_N_BASECLASSES(rtti_type) > 1 && full && (*full) != 1) | |
263 | { | |
264 | if (top) | |
dda83cd7 | 265 | *top = TYPE_BASECLASS_BITPOS (rtti_type, |
0963b4bd | 266 | TYPE_VPTR_FIELDNO(rtti_type)) / 8; |
015a42b4 | 267 | if (top && ((*top) >0)) |
dda83cd7 | 268 | { |
df86565b | 269 | if (rtti_type->length () > known_type->length ()) |
dda83cd7 SM |
270 | { |
271 | if (full) | |
272 | *full=0; | |
273 | } | |
274 | else | |
275 | { | |
276 | if (full) | |
277 | *full=1; | |
278 | } | |
279 | } | |
015a42b4 JB |
280 | } |
281 | else | |
282 | { | |
283 | if (full) | |
dda83cd7 | 284 | *full=1; |
015a42b4 | 285 | } |
015a42b4 JB |
286 | |
287 | return rtti_type; | |
288 | } | |
289 | ||
1514d34e DJ |
290 | /* Return true if the INDEXth field of TYPE is a virtual baseclass |
291 | pointer which is for the base class whose type is BASECLASS. */ | |
292 | ||
293 | static int | |
294 | vb_match (struct type *type, int index, struct type *basetype) | |
295 | { | |
296 | struct type *fieldtype; | |
33d16dd9 | 297 | const char *name = type->field (index).name (); |
0d5cff50 | 298 | const char *field_class_name = NULL; |
1514d34e DJ |
299 | |
300 | if (*name != '_') | |
301 | return 0; | |
302 | /* gcc 2.4 uses _vb$. */ | |
303 | if (name[1] == 'v' && name[2] == 'b' && is_cplus_marker (name[3])) | |
304 | field_class_name = name + 4; | |
305 | /* gcc 2.5 will use __vb_. */ | |
306 | if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_') | |
307 | field_class_name = name + 5; | |
308 | ||
309 | if (field_class_name == NULL) | |
310 | /* This field is not a virtual base class pointer. */ | |
311 | return 0; | |
312 | ||
313 | /* It's a virtual baseclass pointer, now we just need to find out whether | |
314 | it is for this baseclass. */ | |
940da03e | 315 | fieldtype = type->field (index).type (); |
1514d34e | 316 | if (fieldtype == NULL |
78134374 | 317 | || fieldtype->code () != TYPE_CODE_PTR) |
1514d34e DJ |
318 | /* "Can't happen". */ |
319 | return 0; | |
320 | ||
321 | /* What we check for is that either the types are equal (needed for | |
322 | nameless types) or have the same name. This is ugly, and a more | |
323 | elegant solution should be devised (which would probably just push | |
324 | the ugliness into symbol reading unless we change the stabs format). */ | |
27710edb | 325 | if (fieldtype->target_type () == basetype) |
1514d34e DJ |
326 | return 1; |
327 | ||
7d93a1e0 | 328 | if (basetype->name () != NULL |
27710edb | 329 | && fieldtype->target_type ()->name () != NULL |
7d93a1e0 | 330 | && strcmp (basetype->name (), |
27710edb | 331 | fieldtype->target_type ()->name ()) == 0) |
1514d34e DJ |
332 | return 1; |
333 | return 0; | |
334 | } | |
335 | ||
8af8e3bc PA |
336 | /* Compute the offset of the baseclass which is the INDEXth baseclass |
337 | of class TYPE, for value at VALADDR (in host) at ADDRESS (in | |
338 | target). The result is the offset of the baseclass value relative | |
339 | to (the address of)(ARG) + OFFSET. */ | |
1514d34e | 340 | |
f23f4c59 | 341 | static int |
06c4d4dc | 342 | gnuv2_baseclass_offset (struct type *type, int index, |
6b850546 | 343 | const bfd_byte *valaddr, LONGEST embedded_offset, |
8af8e3bc | 344 | CORE_ADDR address, const struct value *val) |
1514d34e DJ |
345 | { |
346 | struct type *basetype = TYPE_BASECLASS (type, index); | |
347 | ||
348 | if (BASETYPE_VIA_VIRTUAL (type, index)) | |
349 | { | |
350 | /* Must hunt for the pointer to this virtual baseclass. */ | |
1f704f76 | 351 | int i, len = type->num_fields (); |
aa1ee363 | 352 | int n_baseclasses = TYPE_N_BASECLASSES (type); |
1514d34e DJ |
353 | |
354 | /* First look for the virtual baseclass pointer | |
dda83cd7 | 355 | in the fields. */ |
1514d34e DJ |
356 | for (i = n_baseclasses; i < len; i++) |
357 | { | |
358 | if (vb_match (type, i, basetype)) | |
359 | { | |
8af8e3bc | 360 | struct type *field_type; |
6b850546 | 361 | LONGEST field_offset; |
8af8e3bc PA |
362 | int field_length; |
363 | CORE_ADDR addr; | |
364 | ||
940da03e | 365 | field_type = check_typedef (type->field (i).type ()); |
b610c045 | 366 | field_offset = type->field (i).loc_bitpos () / 8; |
df86565b | 367 | field_length = field_type->length (); |
8af8e3bc | 368 | |
d00664db TT |
369 | if (!val->bytes_available (embedded_offset + field_offset, |
370 | field_length)) | |
8af8e3bc PA |
371 | throw_error (NOT_AVAILABLE_ERROR, |
372 | _("Virtual baseclass pointer is not available")); | |
1514d34e | 373 | |
8af8e3bc PA |
374 | addr = unpack_pointer (field_type, |
375 | valaddr + embedded_offset + field_offset); | |
376 | ||
377 | return addr - (LONGEST) address + embedded_offset; | |
1514d34e DJ |
378 | } |
379 | } | |
380 | /* Not in the fields, so try looking through the baseclasses. */ | |
381 | for (i = index + 1; i < n_baseclasses; i++) | |
382 | { | |
8af8e3bc PA |
383 | /* Don't go through baseclass_offset, as that wraps |
384 | exceptions, thus, inner exceptions would be wrapped more | |
385 | than once. */ | |
1514d34e | 386 | int boffset = |
8af8e3bc PA |
387 | gnuv2_baseclass_offset (type, i, valaddr, |
388 | embedded_offset, address, val); | |
d8734c88 | 389 | |
1514d34e DJ |
390 | if (boffset) |
391 | return boffset; | |
392 | } | |
8af8e3bc PA |
393 | |
394 | error (_("Baseclass offset not found")); | |
1514d34e DJ |
395 | } |
396 | ||
397 | /* Baseclass is easily computed. */ | |
398 | return TYPE_BASECLASS_BITPOS (type, index) / 8; | |
399 | } | |
015a42b4 JB |
400 | |
401 | static void | |
402 | init_gnuv2_ops (void) | |
403 | { | |
404 | gnu_v2_abi_ops.shortname = "gnu-v2"; | |
405 | gnu_v2_abi_ops.longname = "GNU G++ Version 2 ABI"; | |
406 | gnu_v2_abi_ops.doc = "G++ Version 2 ABI"; | |
407 | gnu_v2_abi_ops.is_destructor_name = gnuv2_is_destructor_name; | |
408 | gnu_v2_abi_ops.is_constructor_name = gnuv2_is_constructor_name; | |
409 | gnu_v2_abi_ops.is_vtable_name = gnuv2_is_vtable_name; | |
410 | gnu_v2_abi_ops.is_operator_name = gnuv2_is_operator_name; | |
411 | gnu_v2_abi_ops.virtual_fn_field = gnuv2_virtual_fn_field; | |
412 | gnu_v2_abi_ops.rtti_type = gnuv2_value_rtti_type; | |
1514d34e | 413 | gnu_v2_abi_ops.baseclass_offset = gnuv2_baseclass_offset; |
015a42b4 JB |
414 | } |
415 | ||
6c265988 | 416 | void _initialize_gnu_v2_abi (); |
015a42b4 | 417 | void |
6c265988 | 418 | _initialize_gnu_v2_abi () |
015a42b4 JB |
419 | { |
420 | init_gnuv2_ops (); | |
fe1f4a5e | 421 | register_cp_abi (&gnu_v2_abi_ops); |
015a42b4 | 422 | } |