1 /* Abstraction of GNU v2 abi.
3 Copyright (C) 2001-2014 Free Software Foundation, Inc.
5 Contributed by Daniel Berlin <dberlin@redhat.com>
7 This file is part of GDB.
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
12 (at your option) any later version.
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.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 #include "gdb-demangle.h"
29 #include "cp-support.h"
30 #include "exceptions.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
));
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
154 vtbl
= value_ptradd (vtbl
, vi
);
155 entry
= value_ind (vtbl
);
158 entry_type
= check_typedef (value_type (entry
));
160 if (TYPE_CODE (entry_type
) == TYPE_CODE_STRUCT
)
162 /* Move the `this' pointer according to the virtual function table. */
163 set_value_offset (arg1
, value_offset (arg1
)
164 + value_as_long (value_field (entry
, 0)));
166 if (!value_lazy (arg1
))
168 set_value_lazy (arg1
, 1);
169 value_fetch_lazy (arg1
);
172 vfn
= value_field (entry
, 2);
174 else if (TYPE_CODE (entry_type
) == TYPE_CODE_PTR
)
177 error (_("I'm confused: virtual function table has bad type"));
178 /* Reinstantiate the function pointer with the correct type. */
179 deprecated_set_value_type (vfn
,
180 lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
)));
188 gnuv2_value_rtti_type (struct value
*v
, int *full
, int *top
, int *using_enc
)
190 struct type
*known_type
;
191 struct type
*rtti_type
;
193 struct bound_minimal_symbol minsym
;
194 char *demangled_name
, *p
;
195 const char *linkage_name
;
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. */
229 btype
= known_type_vptr_basetype
;
230 CHECK_TYPEDEF (btype
);
231 if (btype
!= known_type
)
233 v
= value_cast (btype
, v
);
237 /* We can't use value_ind here, because it would want to use RTTI, and
238 we'd waste a bunch of time figuring out we already know the type.
239 Besides, we don't care about the type, just the actual pointer. */
240 if (value_address (value_field (v
, known_type_vptr_fieldno
)) == 0)
243 vtbl
= value_as_address (value_field (v
, known_type_vptr_fieldno
));
245 /* Try to find a symbol that is the vtable. */
246 minsym
=lookup_minimal_symbol_by_pc(vtbl
);
247 if (minsym
.minsym
==NULL
248 || (linkage_name
=MSYMBOL_LINKAGE_NAME (minsym
.minsym
))==NULL
249 || !is_vtable_name (linkage_name
))
252 /* If we just skip the prefix, we get screwed by namespaces. */
253 demangled_name
=gdb_demangle(linkage_name
,DMGL_PARAMS
|DMGL_ANSI
);
254 p
= strchr (demangled_name
, ' ');
258 /* Lookup the type for the name. */
259 /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
260 rtti_type
= cp_lookup_rtti_type (demangled_name
, NULL
);
261 if (rtti_type
== NULL
)
264 if (TYPE_N_BASECLASSES(rtti_type
) > 1 && full
&& (*full
) != 1)
267 *top
= TYPE_BASECLASS_BITPOS (rtti_type
,
268 TYPE_VPTR_FIELDNO(rtti_type
)) / 8;
269 if (top
&& ((*top
) >0))
271 if (TYPE_LENGTH(rtti_type
) > TYPE_LENGTH(known_type
))
292 /* Return true if the INDEXth field of TYPE is a virtual baseclass
293 pointer which is for the base class whose type is BASECLASS. */
296 vb_match (struct type
*type
, int index
, struct type
*basetype
)
298 struct type
*fieldtype
;
299 const char *name
= TYPE_FIELD_NAME (type
, index
);
300 const char *field_class_name
= NULL
;
304 /* gcc 2.4 uses _vb$. */
305 if (name
[1] == 'v' && name
[2] == 'b' && is_cplus_marker (name
[3]))
306 field_class_name
= name
+ 4;
307 /* gcc 2.5 will use __vb_. */
308 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
309 field_class_name
= name
+ 5;
311 if (field_class_name
== NULL
)
312 /* This field is not a virtual base class pointer. */
315 /* It's a virtual baseclass pointer, now we just need to find out whether
316 it is for this baseclass. */
317 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
318 if (fieldtype
== NULL
319 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
320 /* "Can't happen". */
323 /* What we check for is that either the types are equal (needed for
324 nameless types) or have the same name. This is ugly, and a more
325 elegant solution should be devised (which would probably just push
326 the ugliness into symbol reading unless we change the stabs format). */
327 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
330 if (TYPE_NAME (basetype
) != NULL
331 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
332 && strcmp (TYPE_NAME (basetype
),
333 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))) == 0)
338 /* Compute the offset of the baseclass which is the INDEXth baseclass
339 of class TYPE, for value at VALADDR (in host) at ADDRESS (in
340 target). The result is the offset of the baseclass value relative
341 to (the address of)(ARG) + OFFSET. */
344 gnuv2_baseclass_offset (struct type
*type
, int index
,
345 const bfd_byte
*valaddr
, int embedded_offset
,
346 CORE_ADDR address
, const struct value
*val
)
348 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
350 if (BASETYPE_VIA_VIRTUAL (type
, index
))
352 /* Must hunt for the pointer to this virtual baseclass. */
353 int i
, len
= TYPE_NFIELDS (type
);
354 int n_baseclasses
= TYPE_N_BASECLASSES (type
);
356 /* First look for the virtual baseclass pointer
358 for (i
= n_baseclasses
; i
< len
; i
++)
360 if (vb_match (type
, i
, basetype
))
362 struct type
*field_type
;
367 field_type
= check_typedef (TYPE_FIELD_TYPE (type
, i
));
368 field_offset
= TYPE_FIELD_BITPOS (type
, i
) / 8;
369 field_length
= TYPE_LENGTH (field_type
);
371 if (!value_bytes_available (val
, embedded_offset
+ field_offset
,
373 throw_error (NOT_AVAILABLE_ERROR
,
374 _("Virtual baseclass pointer is not available"));
376 addr
= unpack_pointer (field_type
,
377 valaddr
+ embedded_offset
+ field_offset
);
379 return addr
- (LONGEST
) address
+ embedded_offset
;
382 /* Not in the fields, so try looking through the baseclasses. */
383 for (i
= index
+ 1; i
< n_baseclasses
; i
++)
385 /* Don't go through baseclass_offset, as that wraps
386 exceptions, thus, inner exceptions would be wrapped more
389 gnuv2_baseclass_offset (type
, i
, valaddr
,
390 embedded_offset
, address
, val
);
396 error (_("Baseclass offset not found"));
399 /* Baseclass is easily computed. */
400 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
404 init_gnuv2_ops (void)
406 gnu_v2_abi_ops
.shortname
= "gnu-v2";
407 gnu_v2_abi_ops
.longname
= "GNU G++ Version 2 ABI";
408 gnu_v2_abi_ops
.doc
= "G++ Version 2 ABI";
409 gnu_v2_abi_ops
.is_destructor_name
= gnuv2_is_destructor_name
;
410 gnu_v2_abi_ops
.is_constructor_name
= gnuv2_is_constructor_name
;
411 gnu_v2_abi_ops
.is_vtable_name
= gnuv2_is_vtable_name
;
412 gnu_v2_abi_ops
.is_operator_name
= gnuv2_is_operator_name
;
413 gnu_v2_abi_ops
.virtual_fn_field
= gnuv2_virtual_fn_field
;
414 gnu_v2_abi_ops
.rtti_type
= gnuv2_value_rtti_type
;
415 gnu_v2_abi_ops
.baseclass_offset
= gnuv2_baseclass_offset
;
418 extern initialize_file_ftype _initialize_gnu_v2_abi
; /* -Wmissing-prototypes */
421 _initialize_gnu_v2_abi (void)
424 register_cp_abi (&gnu_v2_abi_ops
);