1 /* Abstraction of GNU v2 abi.
3 Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009
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"
31 #include "gnu-v2-abi.h"
35 struct cp_abi_ops gnu_v2_abi_ops;
37 static int vb_match (struct type *, int, struct type *);
39 static enum dtor_kinds
40 gnuv2_is_destructor_name (const char *name)
42 if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_')
43 || strncmp (name, "__dt__", 6) == 0)
44 return complete_object_dtor;
49 static enum ctor_kinds
50 gnuv2_is_constructor_name (const char *name)
52 if ((name[0] == '_' && name[1] == '_'
53 && (isdigit (name[2]) || strchr ("Qt", name[2])))
54 || strncmp (name, "__ct__", 6) == 0)
55 return complete_object_ctor;
61 gnuv2_is_vtable_name (const char *name)
63 return (((name)[0] == '_'
64 && (((name)[1] == 'V' && (name)[2] == 'T')
65 || ((name)[1] == 'v' && (name)[2] == 't'))
66 && is_cplus_marker ((name)[3])) ||
67 ((name)[0] == '_' && (name)[1] == '_'
68 && (name)[2] == 'v' && (name)[3] == 't' && (name)[4] == '_'));
72 gnuv2_is_operator_name (const char *name)
74 return strncmp (name, "operator", 8) == 0;
78 /* Return a virtual function as a value.
79 ARG1 is the object which provides the virtual function
80 table pointer. *ARG1P is side-effected in calling this function.
81 F is the list of member functions which contains the desired virtual
83 J is an index into F which provides the desired virtual function.
85 TYPE is the type in which F is located. */
87 gnuv2_virtual_fn_field (struct value **arg1p, struct fn_field * f, int j,
88 struct type * type, int offset)
90 struct value *arg1 = *arg1p;
91 struct type *type1 = check_typedef (value_type (arg1));
92 struct type *entry_type;
93 /* First, get the virtual function table pointer. That comes
94 with a strange type, so cast it to type `pointer to long' (which
95 should serve just fine as a function type). Then, index into
96 the table, and convert final value to appropriate function type. */
100 LONGEST vi = (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j);
101 struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
102 struct type *context;
103 struct type *context_vptr_basetype;
104 int context_vptr_fieldno;
106 if (fcontext == NULL)
107 /* We don't have an fcontext (e.g. the program was compiled with
108 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
109 This won't work right for multiple inheritance, but at least we
110 should do as well as GDB 3.x did. */
111 fcontext = TYPE_VPTR_BASETYPE (type);
112 context = lookup_pointer_type (fcontext);
113 /* Now context is a pointer to the basetype containing the vtbl. */
114 if (TYPE_TARGET_TYPE (context) != type1)
116 struct value *tmp = value_cast (context, value_addr (arg1));
117 arg1 = value_ind (tmp);
118 type1 = check_typedef (value_type (arg1));
122 /* Now context is the basetype containing the vtbl. */
124 /* This type may have been defined before its virtual function table
125 was. If so, fill in the virtual function table entry for the
127 context_vptr_fieldno = get_vptr_fieldno (context, &context_vptr_basetype);
128 /* FIXME: What to do if vptr_fieldno is still -1? */
130 /* The virtual function table is now an array of structures
131 which have the form { int16 offset, delta; void *pfn; }. */
132 vtbl = value_primitive_field (arg1, 0, context_vptr_fieldno,
133 context_vptr_basetype);
135 /* With older versions of g++, the vtbl field pointed to an array
136 of structures. Nowadays it points directly to the structure. */
137 if (TYPE_CODE (value_type (vtbl)) == TYPE_CODE_PTR
138 && TYPE_CODE (TYPE_TARGET_TYPE (value_type (vtbl))) == TYPE_CODE_ARRAY)
140 /* Handle the case where the vtbl field points to an
141 array of structures. */
142 vtbl = value_ind (vtbl);
144 /* Index into the virtual function table. This is hard-coded because
145 looking up a field is not cheap, and it may be important to save
146 time, e.g. if the user has set a conditional breakpoint calling
147 a virtual function. */
148 entry = value_subscript (vtbl, vi);
152 /* Handle the case where the vtbl field points directly to a structure. */
153 vtbl = value_ptradd (vtbl, vi);
154 entry = value_ind (vtbl);
157 entry_type = check_typedef (value_type (entry));
159 if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT)
161 /* Move the `this' pointer according to the virtual function table. */
162 set_value_offset (arg1, value_offset (arg1) + value_as_long (value_field (entry, 0)));
164 if (!value_lazy (arg1))
166 set_value_lazy (arg1, 1);
167 value_fetch_lazy (arg1);
170 vfn = value_field (entry, 2);
172 else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR)
175 error (_("I'm confused: virtual function table has bad type"));
176 /* Reinstantiate the function pointer with the correct type. */
177 deprecated_set_value_type (vfn, lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j)));
185 gnuv2_value_rtti_type (struct value *v, int *full, int *top, int *using_enc)
187 struct type *known_type;
188 struct type *rtti_type;
192 char rtti_type_name[256];
194 struct minimal_symbol *minsym;
196 char *demangled_name, *p;
198 struct type *known_type_vptr_basetype;
199 int known_type_vptr_fieldno;
208 /* Get declared type */
209 known_type = value_type (v);
210 CHECK_TYPEDEF (known_type);
211 /* RTTI works only or class objects */
212 if (TYPE_CODE (known_type) != TYPE_CODE_CLASS)
215 /* Plan on this changing in the future as i get around to setting
216 the vtables properly for G++ compiled stuff. Also, I'll be using
217 the type info functions, which are always right. Deal with it
220 /* Try to get the vptr basetype, fieldno. */
221 known_type_vptr_fieldno = get_vptr_fieldno (known_type,
222 &known_type_vptr_basetype);
224 /* If we can't find it, give up. */
225 if (known_type_vptr_fieldno < 0)
228 /* Make sure our basetype and known type match, otherwise, cast
229 so we can get at the vtable properly.
231 btype = known_type_vptr_basetype;
232 CHECK_TYPEDEF (btype);
233 if (btype != known_type )
235 v = value_cast (btype, v);
240 We can't use value_ind here, because it would want to use RTTI, and
241 we'd waste a bunch of time figuring out we already know the type.
242 Besides, we don't care about the type, just the actual pointer
244 if (value_address (value_field (v, known_type_vptr_fieldno)) == 0)
247 vtbl = value_as_address (value_field (v, known_type_vptr_fieldno));
249 /* Try to find a symbol that is the vtable */
250 minsym=lookup_minimal_symbol_by_pc(vtbl);
252 || (demangled_name=SYMBOL_LINKAGE_NAME (minsym))==NULL
253 || !is_vtable_name (demangled_name))
256 /* If we just skip the prefix, we get screwed by namespaces */
257 demangled_name=cplus_demangle(demangled_name,DMGL_PARAMS|DMGL_ANSI);
258 p = strchr (demangled_name, ' ');
262 /* Lookup the type for the name */
263 /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
264 rtti_type = cp_lookup_rtti_type (demangled_name, NULL);
265 if (rtti_type == NULL)
268 if (TYPE_N_BASECLASSES(rtti_type) > 1 && full && (*full) != 1)
271 *top=TYPE_BASECLASS_BITPOS(rtti_type,TYPE_VPTR_FIELDNO(rtti_type))/8;
272 if (top && ((*top) >0))
274 if (TYPE_LENGTH(rtti_type) > TYPE_LENGTH(known_type))
295 /* Return true if the INDEXth field of TYPE is a virtual baseclass
296 pointer which is for the base class whose type is BASECLASS. */
299 vb_match (struct type *type, int index, struct type *basetype)
301 struct type *fieldtype;
302 char *name = TYPE_FIELD_NAME (type, index);
303 char *field_class_name = NULL;
307 /* gcc 2.4 uses _vb$. */
308 if (name[1] == 'v' && name[2] == 'b' && is_cplus_marker (name[3]))
309 field_class_name = name + 4;
310 /* gcc 2.5 will use __vb_. */
311 if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_')
312 field_class_name = name + 5;
314 if (field_class_name == NULL)
315 /* This field is not a virtual base class pointer. */
318 /* It's a virtual baseclass pointer, now we just need to find out whether
319 it is for this baseclass. */
320 fieldtype = TYPE_FIELD_TYPE (type, index);
321 if (fieldtype == NULL
322 || TYPE_CODE (fieldtype) != TYPE_CODE_PTR)
323 /* "Can't happen". */
326 /* What we check for is that either the types are equal (needed for
327 nameless types) or have the same name. This is ugly, and a more
328 elegant solution should be devised (which would probably just push
329 the ugliness into symbol reading unless we change the stabs format). */
330 if (TYPE_TARGET_TYPE (fieldtype) == basetype)
333 if (TYPE_NAME (basetype) != NULL
334 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL
335 && strcmp (TYPE_NAME (basetype),
336 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))) == 0)
341 /* Compute the offset of the baseclass which is
342 the INDEXth baseclass of class TYPE,
343 for value at VALADDR (in host) at ADDRESS (in target).
344 The result is the offset of the baseclass value relative
345 to (the address of)(ARG) + OFFSET.
347 -1 is returned on error. */
350 gnuv2_baseclass_offset (struct type *type, int index,
351 const bfd_byte *valaddr, CORE_ADDR address)
353 struct type *basetype = TYPE_BASECLASS (type, index);
355 if (BASETYPE_VIA_VIRTUAL (type, index))
357 /* Must hunt for the pointer to this virtual baseclass. */
358 int i, len = TYPE_NFIELDS (type);
359 int n_baseclasses = TYPE_N_BASECLASSES (type);
361 /* First look for the virtual baseclass pointer
363 for (i = n_baseclasses; i < len; i++)
365 if (vb_match (type, i, basetype))
368 = unpack_pointer (TYPE_FIELD_TYPE (type, i),
369 valaddr + (TYPE_FIELD_BITPOS (type, i) / 8));
371 return addr - (LONGEST) address;
374 /* Not in the fields, so try looking through the baseclasses. */
375 for (i = index + 1; i < n_baseclasses; i++)
378 baseclass_offset (type, i, valaddr, address);
386 /* Baseclass is easily computed. */
387 return TYPE_BASECLASS_BITPOS (type, index) / 8;
391 init_gnuv2_ops (void)
393 gnu_v2_abi_ops.shortname = "gnu-v2";
394 gnu_v2_abi_ops.longname = "GNU G++ Version 2 ABI";
395 gnu_v2_abi_ops.doc = "G++ Version 2 ABI";
396 gnu_v2_abi_ops.is_destructor_name = gnuv2_is_destructor_name;
397 gnu_v2_abi_ops.is_constructor_name = gnuv2_is_constructor_name;
398 gnu_v2_abi_ops.is_vtable_name = gnuv2_is_vtable_name;
399 gnu_v2_abi_ops.is_operator_name = gnuv2_is_operator_name;
400 gnu_v2_abi_ops.virtual_fn_field = gnuv2_virtual_fn_field;
401 gnu_v2_abi_ops.rtti_type = gnuv2_value_rtti_type;
402 gnu_v2_abi_ops.baseclass_offset = gnuv2_baseclass_offset;
405 extern initialize_file_ftype _initialize_gnu_v2_abi; /* -Wmissing-prototypes */
408 _initialize_gnu_v2_abi (void)
411 register_cp_abi (&gnu_v2_abi_ops);
412 set_cp_abi_as_auto_default (gnu_v2_abi_ops.shortname);