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015a42b4 1/* Abstraction of GNU v2 abi.
1bac305b 2
6aba47ca 3 Copyright (C) 2001, 2002, 2003, 2005, 2007 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
9 This program is free software; you can redistribute it and/or
10 modify
11 it under the terms of the GNU General Public License as published
12 by
13 the Free Software Foundation; either version 2 of the License, or
14 (at your option) any later version.
15
16 This program is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
20
21 You should have received a copy of the GNU General Public License
22 along with this program; if not, write to the Free Software
197e01b6
EZ
23 Foundation, Inc., 51 Franklin Street, Fifth Floor,
24 Boston, MA 02110-1301, USA. */
015a42b4
JB
25
26#include "defs.h"
015a42b4
JB
27#include "gdb_string.h"
28#include "symtab.h"
29#include "gdbtypes.h"
30#include "value.h"
31#include "demangle.h"
32#include "cp-abi.h"
362ff856 33#include "cp-support.h"
6b08edad 34#include "gnu-v2-abi.h"
015a42b4
JB
35
36#include <ctype.h>
37
38struct cp_abi_ops gnu_v2_abi_ops;
39
40static int vb_match (struct type *, int, struct type *);
41
42static enum dtor_kinds
43gnuv2_is_destructor_name (const char *name)
44{
45 if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_')
46 || strncmp (name, "__dt__", 6) == 0)
47 return complete_object_dtor;
48 else
49 return 0;
50}
51
52static enum ctor_kinds
53gnuv2_is_constructor_name (const char *name)
54{
55 if ((name[0] == '_' && name[1] == '_'
56 && (isdigit (name[2]) || strchr ("Qt", name[2])))
57 || strncmp (name, "__ct__", 6) == 0)
58 return complete_object_ctor;
59 else
60 return 0;
61}
62
63static int
64gnuv2_is_vtable_name (const char *name)
65{
66 return (((name)[0] == '_'
67 && (((name)[1] == 'V' && (name)[2] == 'T')
68 || ((name)[1] == 'v' && (name)[2] == 't'))
69 && is_cplus_marker ((name)[3])) ||
70 ((name)[0] == '_' && (name)[1] == '_'
71 && (name)[2] == 'v' && (name)[3] == 't' && (name)[4] == '_'));
72}
73
74static int
75gnuv2_is_operator_name (const char *name)
76{
77 return strncmp (name, "operator", 8) == 0;
78}
79
80\f
81/* Return a virtual function as a value.
82 ARG1 is the object which provides the virtual function
83 table pointer. *ARG1P is side-effected in calling this function.
84 F is the list of member functions which contains the desired virtual
85 function.
86 J is an index into F which provides the desired virtual function.
87
88 TYPE is the type in which F is located. */
e933e538
AC
89static struct value *
90gnuv2_virtual_fn_field (struct value **arg1p, struct fn_field * f, int j,
015a42b4
JB
91 struct type * type, int offset)
92{
e933e538 93 struct value *arg1 = *arg1p;
df407dfe 94 struct type *type1 = check_typedef (value_type (arg1));
015a42b4
JB
95
96
97 struct type *entry_type;
98 /* First, get the virtual function table pointer. That comes
99 with a strange type, so cast it to type `pointer to long' (which
100 should serve just fine as a function type). Then, index into
101 the table, and convert final value to appropriate function type. */
e933e538
AC
102 struct value *entry;
103 struct value *vfn;
104 struct value *vtbl;
105 struct value *vi = value_from_longest (builtin_type_int,
015a42b4
JB
106 (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j));
107 struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
108 struct type *context;
109 if (fcontext == NULL)
110 /* We don't have an fcontext (e.g. the program was compiled with
111 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
112 This won't work right for multiple inheritance, but at least we
113 should do as well as GDB 3.x did. */
114 fcontext = TYPE_VPTR_BASETYPE (type);
115 context = lookup_pointer_type (fcontext);
116 /* Now context is a pointer to the basetype containing the vtbl. */
117 if (TYPE_TARGET_TYPE (context) != type1)
118 {
e933e538 119 struct value *tmp = value_cast (context, value_addr (arg1));
015a42b4 120 arg1 = value_ind (tmp);
df407dfe 121 type1 = check_typedef (value_type (arg1));
015a42b4
JB
122 }
123
124 context = type1;
125 /* Now context is the basetype containing the vtbl. */
126
127 /* This type may have been defined before its virtual function table
128 was. If so, fill in the virtual function table entry for the
129 type now. */
130 if (TYPE_VPTR_FIELDNO (context) < 0)
131 fill_in_vptr_fieldno (context);
132
133 /* The virtual function table is now an array of structures
134 which have the form { int16 offset, delta; void *pfn; }. */
135 vtbl = value_primitive_field (arg1, 0, TYPE_VPTR_FIELDNO (context),
136 TYPE_VPTR_BASETYPE (context));
137
138 /* With older versions of g++, the vtbl field pointed to an array
139 of structures. Nowadays it points directly to the structure. */
df407dfe
AC
140 if (TYPE_CODE (value_type (vtbl)) == TYPE_CODE_PTR
141 && TYPE_CODE (TYPE_TARGET_TYPE (value_type (vtbl))) == TYPE_CODE_ARRAY)
015a42b4
JB
142 {
143 /* Handle the case where the vtbl field points to an
144 array of structures. */
145 vtbl = value_ind (vtbl);
146
147 /* Index into the virtual function table. This is hard-coded because
148 looking up a field is not cheap, and it may be important to save
149 time, e.g. if the user has set a conditional breakpoint calling
150 a virtual function. */
151 entry = value_subscript (vtbl, vi);
152 }
153 else
154 {
155 /* Handle the case where the vtbl field points directly to a structure. */
156 vtbl = value_add (vtbl, vi);
157 entry = value_ind (vtbl);
158 }
159
df407dfe 160 entry_type = check_typedef (value_type (entry));
015a42b4
JB
161
162 if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT)
163 {
164 /* Move the `this' pointer according to the virtual function table. */
f5cf64a7 165 set_value_offset (arg1, value_offset (arg1) + value_as_long (value_field (entry, 0)));
015a42b4 166
d69fe07e 167 if (!value_lazy (arg1))
015a42b4 168 {
dfa52d88 169 set_value_lazy (arg1, 1);
015a42b4
JB
170 value_fetch_lazy (arg1);
171 }
172
173 vfn = value_field (entry, 2);
174 }
175 else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR)
176 vfn = entry;
177 else
8a3fe4f8 178 error (_("I'm confused: virtual function table has bad type"));
015a42b4 179 /* Reinstantiate the function pointer with the correct type. */
04624583 180 deprecated_set_value_type (vfn, lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j)));
015a42b4
JB
181
182 *arg1p = arg1;
183 return vfn;
184}
185
186
b9362cc7 187static struct type *
e933e538 188gnuv2_value_rtti_type (struct value *v, int *full, int *top, int *using_enc)
015a42b4
JB
189{
190 struct type *known_type;
191 struct type *rtti_type;
192 CORE_ADDR coreptr;
e933e538 193 struct value *vp;
015a42b4
JB
194 long top_offset = 0;
195 char rtti_type_name[256];
196 CORE_ADDR vtbl;
197 struct minimal_symbol *minsym;
198 struct symbol *sym;
199 char *demangled_name;
200 struct type *btype;
201
202 if (full)
203 *full = 0;
204 if (top)
205 *top = -1;
206 if (using_enc)
207 *using_enc = 0;
208
209 /* Get declared type */
df407dfe 210 known_type = value_type (v);
015a42b4
JB
211 CHECK_TYPEDEF (known_type);
212 /* RTTI works only or class objects */
213 if (TYPE_CODE (known_type) != TYPE_CODE_CLASS)
214 return NULL;
215
216 /* Plan on this changing in the future as i get around to setting
217 the vtables properly for G++ compiled stuff. Also, I'll be using
218 the type info functions, which are always right. Deal with it
219 until then. */
220
221 /* If the type has no vptr fieldno, try to get it filled in */
222 if (TYPE_VPTR_FIELDNO(known_type) < 0)
223 fill_in_vptr_fieldno(known_type);
224
225 /* If we still can't find one, give up */
226 if (TYPE_VPTR_FIELDNO(known_type) < 0)
227 return NULL;
228
229 /* Make sure our basetype and known type match, otherwise, cast
230 so we can get at the vtable properly.
231 */
232 btype = TYPE_VPTR_BASETYPE (known_type);
233 CHECK_TYPEDEF (btype);
234 if (btype != known_type )
235 {
236 v = value_cast (btype, v);
237 if (using_enc)
238 *using_enc=1;
239 }
240 /*
241 We can't use value_ind here, because it would want to use RTTI, and
242 we'd waste a bunch of time figuring out we already know the type.
243 Besides, we don't care about the type, just the actual pointer
244 */
245 if (VALUE_ADDRESS (value_field (v, TYPE_VPTR_FIELDNO (known_type))) == 0)
246 return NULL;
247
2a73a662 248 vtbl=value_as_address(value_field(v,TYPE_VPTR_FIELDNO(known_type)));
015a42b4
JB
249
250 /* Try to find a symbol that is the vtable */
251 minsym=lookup_minimal_symbol_by_pc(vtbl);
252 if (minsym==NULL
22abf04a 253 || (demangled_name=DEPRECATED_SYMBOL_NAME (minsym))==NULL
015a42b4
JB
254 || !is_vtable_name (demangled_name))
255 return NULL;
256
257 /* If we just skip the prefix, we get screwed by namespaces */
258 demangled_name=cplus_demangle(demangled_name,DMGL_PARAMS|DMGL_ANSI);
259 *(strchr(demangled_name,' '))=0;
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
297static int
298vb_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
348int
06c4d4dc
AC
349gnuv2_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
389static void
390init_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
404extern initialize_file_ftype _initialize_gnu_v2_abi; /* -Wmissing-prototypes */
405
015a42b4
JB
406void
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}