424 lines
13 KiB
C
424 lines
13 KiB
C
/* Abstraction of GNU v2 abi.
|
||
|
||
Copyright (C) 2001-2015 Free Software Foundation, Inc.
|
||
|
||
Contributed by Daniel Berlin <dberlin@redhat.com>
|
||
|
||
This file is part of GDB.
|
||
|
||
This program is free software; you can redistribute it and/or modify
|
||
it under the terms of the GNU General Public License as published by
|
||
the Free Software Foundation; either version 3 of the License, or
|
||
(at your option) any later version.
|
||
|
||
This program is distributed in the hope that it will be useful,
|
||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
GNU General Public License for more details.
|
||
|
||
You should have received a copy of the GNU General Public License
|
||
along with this program. If not, see <http://www.gnu.org/licenses/>. */
|
||
|
||
#include "defs.h"
|
||
#include "symtab.h"
|
||
#include "gdbtypes.h"
|
||
#include "value.h"
|
||
#include "demangle.h"
|
||
#include "gdb-demangle.h"
|
||
#include "cp-abi.h"
|
||
#include "cp-support.h"
|
||
#include <ctype.h>
|
||
|
||
struct cp_abi_ops gnu_v2_abi_ops;
|
||
|
||
static int vb_match (struct type *, int, struct type *);
|
||
|
||
static enum dtor_kinds
|
||
gnuv2_is_destructor_name (const char *name)
|
||
{
|
||
if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_')
|
||
|| startswith (name, "__dt__"))
|
||
return complete_object_dtor;
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
static enum ctor_kinds
|
||
gnuv2_is_constructor_name (const char *name)
|
||
{
|
||
if ((name[0] == '_' && name[1] == '_'
|
||
&& (isdigit (name[2]) || strchr ("Qt", name[2])))
|
||
|| startswith (name, "__ct__"))
|
||
return complete_object_ctor;
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
gnuv2_is_vtable_name (const char *name)
|
||
{
|
||
return (((name)[0] == '_'
|
||
&& (((name)[1] == 'V' && (name)[2] == 'T')
|
||
|| ((name)[1] == 'v' && (name)[2] == 't'))
|
||
&& is_cplus_marker ((name)[3])) ||
|
||
((name)[0] == '_' && (name)[1] == '_'
|
||
&& (name)[2] == 'v' && (name)[3] == 't' && (name)[4] == '_'));
|
||
}
|
||
|
||
static int
|
||
gnuv2_is_operator_name (const char *name)
|
||
{
|
||
return startswith (name, "operator");
|
||
}
|
||
|
||
|
||
/* Return a virtual function as a value.
|
||
ARG1 is the object which provides the virtual function
|
||
table pointer. *ARG1P is side-effected in calling this function.
|
||
F is the list of member functions which contains the desired virtual
|
||
function.
|
||
J is an index into F which provides the desired virtual function.
|
||
|
||
TYPE is the type in which F is located. */
|
||
static struct value *
|
||
gnuv2_virtual_fn_field (struct value **arg1p, struct fn_field * f, int j,
|
||
struct type * type, int offset)
|
||
{
|
||
struct value *arg1 = *arg1p;
|
||
struct type *type1 = check_typedef (value_type (arg1));
|
||
struct type *entry_type;
|
||
/* First, get the virtual function table pointer. That comes
|
||
with a strange type, so cast it to type `pointer to long' (which
|
||
should serve just fine as a function type). Then, index into
|
||
the table, and convert final value to appropriate function type. */
|
||
struct value *entry;
|
||
struct value *vfn;
|
||
struct value *vtbl;
|
||
LONGEST vi = (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j);
|
||
struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
|
||
struct type *context;
|
||
struct type *context_vptr_basetype;
|
||
int context_vptr_fieldno;
|
||
|
||
if (fcontext == NULL)
|
||
/* We don't have an fcontext (e.g. the program was compiled with
|
||
g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
|
||
This won't work right for multiple inheritance, but at least we
|
||
should do as well as GDB 3.x did. */
|
||
fcontext = TYPE_VPTR_BASETYPE (type);
|
||
context = lookup_pointer_type (fcontext);
|
||
/* Now context is a pointer to the basetype containing the vtbl. */
|
||
if (TYPE_TARGET_TYPE (context) != type1)
|
||
{
|
||
struct value *tmp = value_cast (context, value_addr (arg1));
|
||
|
||
arg1 = value_ind (tmp);
|
||
type1 = check_typedef (value_type (arg1));
|
||
}
|
||
|
||
context = type1;
|
||
/* Now context is the basetype containing the vtbl. */
|
||
|
||
/* This type may have been defined before its virtual function table
|
||
was. If so, fill in the virtual function table entry for the
|
||
type now. */
|
||
context_vptr_fieldno = get_vptr_fieldno (context, &context_vptr_basetype);
|
||
/* FIXME: What to do if vptr_fieldno is still -1? */
|
||
|
||
/* The virtual function table is now an array of structures
|
||
which have the form { int16 offset, delta; void *pfn; }. */
|
||
vtbl = value_primitive_field (arg1, 0, context_vptr_fieldno,
|
||
context_vptr_basetype);
|
||
|
||
/* With older versions of g++, the vtbl field pointed to an array
|
||
of structures. Nowadays it points directly to the structure. */
|
||
if (TYPE_CODE (value_type (vtbl)) == TYPE_CODE_PTR
|
||
&& TYPE_CODE (TYPE_TARGET_TYPE (value_type (vtbl))) == TYPE_CODE_ARRAY)
|
||
{
|
||
/* Handle the case where the vtbl field points to an
|
||
array of structures. */
|
||
vtbl = value_ind (vtbl);
|
||
|
||
/* Index into the virtual function table. This is hard-coded because
|
||
looking up a field is not cheap, and it may be important to save
|
||
time, e.g. if the user has set a conditional breakpoint calling
|
||
a virtual function. */
|
||
entry = value_subscript (vtbl, vi);
|
||
}
|
||
else
|
||
{
|
||
/* Handle the case where the vtbl field points directly to a
|
||
structure. */
|
||
vtbl = value_ptradd (vtbl, vi);
|
||
entry = value_ind (vtbl);
|
||
}
|
||
|
||
entry_type = check_typedef (value_type (entry));
|
||
|
||
if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT)
|
||
{
|
||
/* Move the `this' pointer according to the virtual function table. */
|
||
set_value_offset (arg1, value_offset (arg1)
|
||
+ value_as_long (value_field (entry, 0)));
|
||
|
||
if (!value_lazy (arg1))
|
||
{
|
||
set_value_lazy (arg1, 1);
|
||
value_fetch_lazy (arg1);
|
||
}
|
||
|
||
vfn = value_field (entry, 2);
|
||
}
|
||
else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR)
|
||
vfn = entry;
|
||
else
|
||
error (_("I'm confused: virtual function table has bad type"));
|
||
/* Reinstantiate the function pointer with the correct type. */
|
||
deprecated_set_value_type (vfn,
|
||
lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j)));
|
||
|
||
*arg1p = arg1;
|
||
return vfn;
|
||
}
|
||
|
||
|
||
static struct type *
|
||
gnuv2_value_rtti_type (struct value *v, int *full, int *top, int *using_enc)
|
||
{
|
||
struct type *known_type;
|
||
struct type *rtti_type;
|
||
CORE_ADDR vtbl;
|
||
struct bound_minimal_symbol minsym;
|
||
char *demangled_name, *p;
|
||
const char *linkage_name;
|
||
struct type *btype;
|
||
struct type *known_type_vptr_basetype;
|
||
int known_type_vptr_fieldno;
|
||
|
||
if (full)
|
||
*full = 0;
|
||
if (top)
|
||
*top = -1;
|
||
if (using_enc)
|
||
*using_enc = 0;
|
||
|
||
/* Get declared type. */
|
||
known_type = value_type (v);
|
||
known_type = check_typedef (known_type);
|
||
/* RTTI works only or class objects. */
|
||
if (TYPE_CODE (known_type) != TYPE_CODE_STRUCT)
|
||
return NULL;
|
||
|
||
/* Plan on this changing in the future as i get around to setting
|
||
the vtables properly for G++ compiled stuff. Also, I'll be using
|
||
the type info functions, which are always right. Deal with it
|
||
until then. */
|
||
|
||
/* Try to get the vptr basetype, fieldno. */
|
||
known_type_vptr_fieldno = get_vptr_fieldno (known_type,
|
||
&known_type_vptr_basetype);
|
||
|
||
/* If we can't find it, give up. */
|
||
if (known_type_vptr_fieldno < 0)
|
||
return NULL;
|
||
|
||
/* Make sure our basetype and known type match, otherwise, cast
|
||
so we can get at the vtable properly. */
|
||
btype = known_type_vptr_basetype;
|
||
btype = check_typedef (btype);
|
||
if (btype != known_type )
|
||
{
|
||
v = value_cast (btype, v);
|
||
if (using_enc)
|
||
*using_enc=1;
|
||
}
|
||
/* We can't use value_ind here, because it would want to use RTTI, and
|
||
we'd waste a bunch of time figuring out we already know the type.
|
||
Besides, we don't care about the type, just the actual pointer. */
|
||
if (value_address (value_field (v, known_type_vptr_fieldno)) == 0)
|
||
return NULL;
|
||
|
||
vtbl = value_as_address (value_field (v, known_type_vptr_fieldno));
|
||
|
||
/* Try to find a symbol that is the vtable. */
|
||
minsym=lookup_minimal_symbol_by_pc(vtbl);
|
||
if (minsym.minsym==NULL
|
||
|| (linkage_name=MSYMBOL_LINKAGE_NAME (minsym.minsym))==NULL
|
||
|| !is_vtable_name (linkage_name))
|
||
return NULL;
|
||
|
||
/* If we just skip the prefix, we get screwed by namespaces. */
|
||
demangled_name=gdb_demangle(linkage_name,DMGL_PARAMS|DMGL_ANSI);
|
||
p = strchr (demangled_name, ' ');
|
||
if (p)
|
||
*p = '\0';
|
||
|
||
/* Lookup the type for the name. */
|
||
/* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */
|
||
rtti_type = cp_lookup_rtti_type (demangled_name, NULL);
|
||
if (rtti_type == NULL)
|
||
return NULL;
|
||
|
||
if (TYPE_N_BASECLASSES(rtti_type) > 1 && full && (*full) != 1)
|
||
{
|
||
if (top)
|
||
*top = TYPE_BASECLASS_BITPOS (rtti_type,
|
||
TYPE_VPTR_FIELDNO(rtti_type)) / 8;
|
||
if (top && ((*top) >0))
|
||
{
|
||
if (TYPE_LENGTH(rtti_type) > TYPE_LENGTH(known_type))
|
||
{
|
||
if (full)
|
||
*full=0;
|
||
}
|
||
else
|
||
{
|
||
if (full)
|
||
*full=1;
|
||
}
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (full)
|
||
*full=1;
|
||
}
|
||
|
||
return rtti_type;
|
||
}
|
||
|
||
/* Return true if the INDEXth field of TYPE is a virtual baseclass
|
||
pointer which is for the base class whose type is BASECLASS. */
|
||
|
||
static int
|
||
vb_match (struct type *type, int index, struct type *basetype)
|
||
{
|
||
struct type *fieldtype;
|
||
const char *name = TYPE_FIELD_NAME (type, index);
|
||
const char *field_class_name = NULL;
|
||
|
||
if (*name != '_')
|
||
return 0;
|
||
/* gcc 2.4 uses _vb$. */
|
||
if (name[1] == 'v' && name[2] == 'b' && is_cplus_marker (name[3]))
|
||
field_class_name = name + 4;
|
||
/* gcc 2.5 will use __vb_. */
|
||
if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_')
|
||
field_class_name = name + 5;
|
||
|
||
if (field_class_name == NULL)
|
||
/* This field is not a virtual base class pointer. */
|
||
return 0;
|
||
|
||
/* It's a virtual baseclass pointer, now we just need to find out whether
|
||
it is for this baseclass. */
|
||
fieldtype = TYPE_FIELD_TYPE (type, index);
|
||
if (fieldtype == NULL
|
||
|| TYPE_CODE (fieldtype) != TYPE_CODE_PTR)
|
||
/* "Can't happen". */
|
||
return 0;
|
||
|
||
/* What we check for is that either the types are equal (needed for
|
||
nameless types) or have the same name. This is ugly, and a more
|
||
elegant solution should be devised (which would probably just push
|
||
the ugliness into symbol reading unless we change the stabs format). */
|
||
if (TYPE_TARGET_TYPE (fieldtype) == basetype)
|
||
return 1;
|
||
|
||
if (TYPE_NAME (basetype) != NULL
|
||
&& TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL
|
||
&& strcmp (TYPE_NAME (basetype),
|
||
TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))) == 0)
|
||
return 1;
|
||
return 0;
|
||
}
|
||
|
||
/* Compute the offset of the baseclass which is the INDEXth baseclass
|
||
of class TYPE, for value at VALADDR (in host) at ADDRESS (in
|
||
target). The result is the offset of the baseclass value relative
|
||
to (the address of)(ARG) + OFFSET. */
|
||
|
||
static int
|
||
gnuv2_baseclass_offset (struct type *type, int index,
|
||
const bfd_byte *valaddr, int embedded_offset,
|
||
CORE_ADDR address, const struct value *val)
|
||
{
|
||
struct type *basetype = TYPE_BASECLASS (type, index);
|
||
|
||
if (BASETYPE_VIA_VIRTUAL (type, index))
|
||
{
|
||
/* Must hunt for the pointer to this virtual baseclass. */
|
||
int i, len = TYPE_NFIELDS (type);
|
||
int n_baseclasses = TYPE_N_BASECLASSES (type);
|
||
|
||
/* First look for the virtual baseclass pointer
|
||
in the fields. */
|
||
for (i = n_baseclasses; i < len; i++)
|
||
{
|
||
if (vb_match (type, i, basetype))
|
||
{
|
||
struct type *field_type;
|
||
int field_offset;
|
||
int field_length;
|
||
CORE_ADDR addr;
|
||
|
||
field_type = check_typedef (TYPE_FIELD_TYPE (type, i));
|
||
field_offset = TYPE_FIELD_BITPOS (type, i) / 8;
|
||
field_length = TYPE_LENGTH (field_type);
|
||
|
||
if (!value_bytes_available (val, embedded_offset + field_offset,
|
||
field_length))
|
||
throw_error (NOT_AVAILABLE_ERROR,
|
||
_("Virtual baseclass pointer is not available"));
|
||
|
||
addr = unpack_pointer (field_type,
|
||
valaddr + embedded_offset + field_offset);
|
||
|
||
return addr - (LONGEST) address + embedded_offset;
|
||
}
|
||
}
|
||
/* Not in the fields, so try looking through the baseclasses. */
|
||
for (i = index + 1; i < n_baseclasses; i++)
|
||
{
|
||
/* Don't go through baseclass_offset, as that wraps
|
||
exceptions, thus, inner exceptions would be wrapped more
|
||
than once. */
|
||
int boffset =
|
||
gnuv2_baseclass_offset (type, i, valaddr,
|
||
embedded_offset, address, val);
|
||
|
||
if (boffset)
|
||
return boffset;
|
||
}
|
||
|
||
error (_("Baseclass offset not found"));
|
||
}
|
||
|
||
/* Baseclass is easily computed. */
|
||
return TYPE_BASECLASS_BITPOS (type, index) / 8;
|
||
}
|
||
|
||
static void
|
||
init_gnuv2_ops (void)
|
||
{
|
||
gnu_v2_abi_ops.shortname = "gnu-v2";
|
||
gnu_v2_abi_ops.longname = "GNU G++ Version 2 ABI";
|
||
gnu_v2_abi_ops.doc = "G++ Version 2 ABI";
|
||
gnu_v2_abi_ops.is_destructor_name = gnuv2_is_destructor_name;
|
||
gnu_v2_abi_ops.is_constructor_name = gnuv2_is_constructor_name;
|
||
gnu_v2_abi_ops.is_vtable_name = gnuv2_is_vtable_name;
|
||
gnu_v2_abi_ops.is_operator_name = gnuv2_is_operator_name;
|
||
gnu_v2_abi_ops.virtual_fn_field = gnuv2_virtual_fn_field;
|
||
gnu_v2_abi_ops.rtti_type = gnuv2_value_rtti_type;
|
||
gnu_v2_abi_ops.baseclass_offset = gnuv2_baseclass_offset;
|
||
}
|
||
|
||
extern initialize_file_ftype _initialize_gnu_v2_abi; /* -Wmissing-prototypes */
|
||
|
||
void
|
||
_initialize_gnu_v2_abi (void)
|
||
{
|
||
init_gnuv2_ops ();
|
||
register_cp_abi (&gnu_v2_abi_ops);
|
||
}
|