1 /* Abstraction of GNU v2 abi.
3 Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 Contributed by Daniel Berlin <dberlin@redhat.com>
8 This file is part of GDB.
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
13 (at your option) any later version.
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.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "gdb_string.h"
30 #include "cp-support.h"
34 struct cp_abi_ops gnu_v2_abi_ops;
36 static int vb_match (struct type *, int, struct type *);
38 static enum dtor_kinds
39 gnuv2_is_destructor_name (const char *name)
41 if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_')
42 || strncmp (name, "__dt__", 6) == 0)
43 return complete_object_dtor;
48 static enum ctor_kinds
49 gnuv2_is_constructor_name (const char *name)
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;
60 gnuv2_is_vtable_name (const char *name)
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] == '_'));
71 gnuv2_is_operator_name (const char *name)
73 return strncmp (name, "operator", 8) == 0;
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
82 J is an index into F which provides the desired virtual function.
84 TYPE is the type in which F is located. */
86 gnuv2_virtual_fn_field (struct value **arg1p, struct fn_field * f, int j,
87 struct type * type, int offset)
89 struct value *arg1 = *arg1p;
90 struct type *type1 = check_typedef (value_type (arg1));
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. */
99 LONGEST vi = (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j);
100 struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
101 struct type *context;
102 struct type *context_vptr_basetype;
103 int context_vptr_fieldno;
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)
115 struct value *tmp = value_cast (context, value_addr (arg1));
116 arg1 = value_ind (tmp);
117 type1 = check_typedef (value_type (arg1));
121 /* Now context is the basetype containing the vtbl. */
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
126 context_vptr_fieldno = get_vptr_fieldno (context, &context_vptr_basetype);
127 /* FIXME: What to do if vptr_fieldno is still -1? */
129 /* The virtual function table is now an array of structures
130 which have the form { int16 offset, delta; void *pfn; }. */
131 vtbl = value_primitive_field (arg1, 0, context_vptr_fieldno,
132 context_vptr_basetype);
134 /* With older versions of g++, the vtbl field pointed to an array
135 of structures. Nowadays it points directly to the structure. */
136 if (TYPE_CODE (value_type (vtbl)) == TYPE_CODE_PTR
137 && TYPE_CODE (TYPE_TARGET_TYPE (value_type (vtbl))) == TYPE_CODE_ARRAY)
139 /* Handle the case where the vtbl field points to an
140 array of structures. */
141 vtbl = value_ind (vtbl);
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);
151 /* Handle the case where the vtbl field points directly to a structure. */
152 vtbl = value_ptradd (vtbl, vi);
153 entry = value_ind (vtbl);
156 entry_type = check_typedef (value_type (entry));
158 if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT)
160 /* Move the `this' pointer according to the virtual function table. */
161 set_value_offset (arg1, value_offset (arg1) + value_as_long (value_field (entry, 0)));
163 if (!value_lazy (arg1))
165 set_value_lazy (arg1, 1);
166 value_fetch_lazy (arg1);
169 vfn = value_field (entry, 2);
171 else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR)
174 error (_("I'm confused: virtual function table has bad type"));
175 /* Reinstantiate the function pointer with the correct type. */
176 deprecated_set_value_type (vfn, lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j)));
184 gnuv2_value_rtti_type (struct value *v, int *full, int *top, int *using_enc)
186 struct type *known_type;
187 struct type *rtti_type;
191 char rtti_type_name[256];
193 struct minimal_symbol *minsym;
195 char *demangled_name, *p;
197 struct type *known_type_vptr_basetype;
198 int known_type_vptr_fieldno;
207 /* Get declared type */
208 known_type = value_type (v);
209 CHECK_TYPEDEF (known_type);
210 /* RTTI works only or class objects */
211 if (TYPE_CODE (known_type) != TYPE_CODE_CLASS)
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
219 /* Try to get the vptr basetype, fieldno. */
220 known_type_vptr_fieldno = get_vptr_fieldno (known_type,
221 &known_type_vptr_basetype);
223 /* If we can't find it, give up. */
224 if (known_type_vptr_fieldno < 0)
227 /* Make sure our basetype and known type match, otherwise, cast
228 so we can get at the vtable properly.
230 btype = known_type_vptr_basetype;
231 CHECK_TYPEDEF (btype);
232 if (btype != known_type )
234 v = value_cast (btype, v);
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
243 if (value_address (value_field (v, known_type_vptr_fieldno)) == 0)
246 vtbl = value_as_address (value_field (v, known_type_vptr_fieldno));
248 /* Try to find a symbol that is the vtable */
249 minsym=lookup_minimal_symbol_by_pc(vtbl);
251 || (demangled_name=SYMBOL_LINKAGE_NAME (minsym))==NULL
252 || !is_vtable_name (demangled_name))
255 /* If we just skip the prefix, we get screwed by namespaces */
256 demangled_name=cplus_demangle(demangled_name,DMGL_PARAMS|DMGL_ANSI);
257 p = strchr (demangled_name, ' ');
261 /* Lookup the type for the name */
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)
267 if (TYPE_N_BASECLASSES(rtti_type) > 1 && full && (*full) != 1)
270 *top=TYPE_BASECLASS_BITPOS(rtti_type,TYPE_VPTR_FIELDNO(rtti_type))/8;
271 if (top && ((*top) >0))
273 if (TYPE_LENGTH(rtti_type) > TYPE_LENGTH(known_type))
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. */
298 vb_match (struct type *type, int index, struct type *basetype)
300 struct type *fieldtype;
301 char *name = TYPE_FIELD_NAME (type, index);
302 char *field_class_name = NULL;
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;
313 if (field_class_name == NULL)
314 /* This field is not a virtual base class pointer. */
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". */
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)
332 if (TYPE_NAME (basetype) != NULL
333 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL
334 && strcmp (TYPE_NAME (basetype),
335 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))) == 0)
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.
346 -1 is returned on error. */
349 gnuv2_baseclass_offset (struct type *type, int index,
350 const bfd_byte *valaddr, CORE_ADDR address)
352 struct type *basetype = TYPE_BASECLASS (type, index);
354 if (BASETYPE_VIA_VIRTUAL (type, index))
356 /* Must hunt for the pointer to this virtual baseclass. */
357 int i, len = TYPE_NFIELDS (type);
358 int n_baseclasses = TYPE_N_BASECLASSES (type);
360 /* First look for the virtual baseclass pointer
362 for (i = n_baseclasses; i < len; i++)
364 if (vb_match (type, i, basetype))
367 = unpack_pointer (TYPE_FIELD_TYPE (type, i),
368 valaddr + (TYPE_FIELD_BITPOS (type, i) / 8));
370 return addr - (LONGEST) address;
373 /* Not in the fields, so try looking through the baseclasses. */
374 for (i = index + 1; i < n_baseclasses; i++)
377 baseclass_offset (type, i, valaddr, address);
385 /* Baseclass is easily computed. */
386 return TYPE_BASECLASS_BITPOS (type, index) / 8;
390 init_gnuv2_ops (void)
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;
401 gnu_v2_abi_ops.baseclass_offset = gnuv2_baseclass_offset;
404 extern initialize_file_ftype _initialize_gnu_v2_abi; /* -Wmissing-prototypes */
407 _initialize_gnu_v2_abi (void)
410 register_cp_abi (&gnu_v2_abi_ops);
411 set_cp_abi_as_auto_default (gnu_v2_abi_ops.shortname);