[binutils.git] / gdb / gnu-v2-abi.c

/* Abstraction of GNU v2 abi.

   Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009
   Free Software Foundation, Inc.

   Contributed by Daniel Berlin <[email protected]>

   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 "gdb_string.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "value.h"
#include "demangle.h"
#include "cp-abi.h"
#include "cp-support.h"
#include "gnu-v2-abi.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] == '_')
      || strncmp (name, "__dt__", 6) == 0)
    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])))
      || strncmp (name, "__ct__", 6) == 0)
    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 strncmp (name, "operator", 8) == 0;
}

\f
/* 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 coreptr;
  struct value *vp;
  long top_offset = 0;
  char rtti_type_name[256];
  CORE_ADDR vtbl;
  struct minimal_symbol *minsym;
  struct symbol *sym;
  char *demangled_name, *p;
  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);
  CHECK_TYPEDEF (known_type);
  /* RTTI works only or class objects */
  if (TYPE_CODE (known_type) != TYPE_CODE_CLASS)
    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;
  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==NULL
      || (demangled_name=SYMBOL_LINKAGE_NAME (minsym))==NULL
      || !is_vtable_name (demangled_name))
    return NULL;

  /* If we just skip the prefix, we get screwed by namespaces */
  demangled_name=cplus_demangle(demangled_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;
  char *name = TYPE_FIELD_NAME (type, index);
  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.

   -1 is returned on error. */

int
gnuv2_baseclass_offset (struct type *type, int index,
			const bfd_byte *valaddr, CORE_ADDR address)
{
  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))
	    {
	      CORE_ADDR addr
	      = unpack_pointer (TYPE_FIELD_TYPE (type, i),
				valaddr + (TYPE_FIELD_BITPOS (type, i) / 8));

	      return addr - (LONGEST) address;
	    }
	}
      /* Not in the fields, so try looking through the baseclasses.  */
      for (i = index + 1; i < n_baseclasses; i++)
	{
	  int boffset =
	  baseclass_offset (type, i, valaddr, address);
	  if (boffset)
	    return boffset;
	}
      /* Not found.  */
      return -1;
    }

  /* 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);
  set_cp_abi_as_auto_default (gnu_v2_abi_ops.shortname);
}
Commit	Line	Data
015a42b4	1	/* Abstraction of GNU v2 abi.
1bac305b	2
0fb0cc75	3	Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009
9b254dd1	4	Free Software Foundation, Inc.
1bac305b	5
015a42b4	6	Contributed by Daniel Berlin <[email protected]>
015a42b4 JB	7
	8	This file is part of GDB.
	9
a9762ec7 JB	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
015a42b4 JB	13	(at your option) any later version.
	14
	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.
	19
	20	You should have received a copy of the GNU General Public License
a9762ec7	21	along with this program. If not, see <http://www.gnu.org/licenses/>. */
015a42b4 JB	22
015a42b4 JB	23	#include "defs.h"
015a42b4 JB	24	#include "gdb_string.h"
	25	#include "symtab.h"
	26	#include "gdbtypes.h"
	27	#include "value.h"
	28	#include "demangle.h"
	29	#include "cp-abi.h"
362ff856	30	#include "cp-support.h"
6b08edad	31	#include "gnu-v2-abi.h"
015a42b4 JB	32
	33	#include <ctype.h>
	34
	35	struct cp_abi_ops gnu_v2_abi_ops;
	36
	37	static int vb_match (struct type , int, struct type );
	38
	39	static enum dtor_kinds
	40	gnuv2_is_destructor_name (const char *name)
	41	{
	42	if ((name[0] == '_' && is_cplus_marker (name[1]) && name[2] == '_')
	43	\|\| strncmp (name, "__dt__", 6) == 0)
	44	return complete_object_dtor;
	45	else
	46	return 0;
	47	}
	48
	49	static enum ctor_kinds
	50	gnuv2_is_constructor_name (const char *name)
	51	{
	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;
	56	else
	57	return 0;
	58	}
	59
	60	static int
	61	gnuv2_is_vtable_name (const char *name)
	62	{
	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] == '_'));
	69	}
	70
	71	static int
	72	gnuv2_is_operator_name (const char *name)
	73	{
	74	return strncmp (name, "operator", 8) == 0;
	75	}
	76
	77	\f
	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
	82	function.
	83	J is an index into F which provides the desired virtual function.
	84
	85	TYPE is the type in which F is located. */
e933e538 AC	86	static struct value *
e933e538 AC	87	gnuv2_virtual_fn_field (struct value *arg1p, struct fn_field f, int j,
015a42b4 JB	88	struct type * type, int offset)
015a42b4 JB	89	{
e933e538	90	struct value arg1 = arg1p;
df407dfe	91	struct type *type1 = check_typedef (value_type (arg1));
015a42b4 JB	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. */
e933e538 AC	97	struct value *entry;
	98	struct value *vfn;
	99	struct value *vtbl;
2497b498	100	LONGEST vi = (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j);
015a42b4 JB	101	struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
015a42b4 JB	102	struct type *context;
81fe8080 DE	103	struct type *context_vptr_basetype;
	104	int context_vptr_fieldno;
	105
015a42b4 JB	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)
	115	{
e933e538	116	struct value *tmp = value_cast (context, value_addr (arg1));
015a42b4	117	arg1 = value_ind (tmp);
df407dfe	118	type1 = check_typedef (value_type (arg1));
015a42b4 JB	119	}
	120
	121	context = type1;
	122	/* Now context is the basetype containing the vtbl. */
	123
	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
	126	type now. */
81fe8080 DE	127	context_vptr_fieldno = get_vptr_fieldno (context, &context_vptr_basetype);
81fe8080 DE	128	/* FIXME: What to do if vptr_fieldno is still -1? */
015a42b4 JB	129
	130	/* The virtual function table is now an array of structures
	131	which have the form { int16 offset, delta; void pfn; }. /
81fe8080 DE	132	vtbl = value_primitive_field (arg1, 0, context_vptr_fieldno,
81fe8080 DE	133	context_vptr_basetype);
015a42b4 JB	134
	135	/* With older versions of g++, the vtbl field pointed to an array
	136	of structures. Nowadays it points directly to the structure. */
df407dfe AC	137	if (TYPE_CODE (value_type (vtbl)) == TYPE_CODE_PTR
df407dfe AC	138	&& TYPE_CODE (TYPE_TARGET_TYPE (value_type (vtbl))) == TYPE_CODE_ARRAY)
015a42b4 JB	139	{
	140	/* Handle the case where the vtbl field points to an
	141	array of structures. */
	142	vtbl = value_ind (vtbl);
	143
	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);
	149	}
	150	else
	151	{
	152	/* Handle the case where the vtbl field points directly to a structure. */
89eef114	153	vtbl = value_ptradd (vtbl, vi);
015a42b4 JB	154	entry = value_ind (vtbl);
	155	}
	156
df407dfe	157	entry_type = check_typedef (value_type (entry));
015a42b4 JB	158
	159	if (TYPE_CODE (entry_type) == TYPE_CODE_STRUCT)
	160	{
	161	/* Move the `this' pointer according to the virtual function table. */
f5cf64a7	162	set_value_offset (arg1, value_offset (arg1) + value_as_long (value_field (entry, 0)));
015a42b4	163
d69fe07e	164	if (!value_lazy (arg1))
015a42b4	165	{
dfa52d88	166	set_value_lazy (arg1, 1);
015a42b4 JB	167	value_fetch_lazy (arg1);
	168	}
	169
	170	vfn = value_field (entry, 2);
	171	}
	172	else if (TYPE_CODE (entry_type) == TYPE_CODE_PTR)
	173	vfn = entry;
	174	else
8a3fe4f8	175	error (_("I'm confused: virtual function table has bad type"));
015a42b4	176	/* Reinstantiate the function pointer with the correct type. */
04624583	177	deprecated_set_value_type (vfn, lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j)));
015a42b4 JB	178
	179	*arg1p = arg1;
	180	return vfn;
	181	}
	182
	183
b9362cc7	184	static struct type *
e933e538	185	gnuv2_value_rtti_type (struct value v, int full, int top, int using_enc)
015a42b4 JB	186	{
	187	struct type *known_type;
	188	struct type *rtti_type;
	189	CORE_ADDR coreptr;
e933e538	190	struct value *vp;
015a42b4 JB	191	long top_offset = 0;
	192	char rtti_type_name[256];
	193	CORE_ADDR vtbl;
	194	struct minimal_symbol *minsym;
	195	struct symbol *sym;
7d63ec12	196	char demangled_name, p;
015a42b4	197	struct type *btype;
81fe8080 DE	198	struct type *known_type_vptr_basetype;
81fe8080 DE	199	int known_type_vptr_fieldno;
015a42b4 JB	200
	201	if (full)
	202	*full = 0;
	203	if (top)
	204	*top = -1;
	205	if (using_enc)
	206	*using_enc = 0;
	207
	208	/* Get declared type */
df407dfe	209	known_type = value_type (v);
015a42b4 JB	210	CHECK_TYPEDEF (known_type);
	211	/* RTTI works only or class objects */
	212	if (TYPE_CODE (known_type) != TYPE_CODE_CLASS)
	213	return NULL;
	214
	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
	218	until then. */
	219
81fe8080 DE	220	/* Try to get the vptr basetype, fieldno. */
	221	known_type_vptr_fieldno = get_vptr_fieldno (known_type,
	222	&known_type_vptr_basetype);
015a42b4	223
81fe8080 DE	224	/* If we can't find it, give up. */
81fe8080 DE	225	if (known_type_vptr_fieldno < 0)
015a42b4 JB	226	return NULL;
	227
	228	/* Make sure our basetype and known type match, otherwise, cast
	229	so we can get at the vtable properly.
	230	*/
81fe8080	231	btype = known_type_vptr_basetype;
015a42b4 JB	232	CHECK_TYPEDEF (btype);
	233	if (btype != known_type )
	234	{
	235	v = value_cast (btype, v);
	236	if (using_enc)
	237	*using_enc=1;
	238	}
	239	/*
	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
	243	*/
42ae5230	244	if (value_address (value_field (v, known_type_vptr_fieldno)) == 0)
015a42b4 JB	245	return NULL;
015a42b4 JB	246
81fe8080	247	vtbl = value_as_address (value_field (v, known_type_vptr_fieldno));
015a42b4 JB	248
	249	/* Try to find a symbol that is the vtable */
	250	minsym=lookup_minimal_symbol_by_pc(vtbl);
	251	if (minsym==NULL
3567439c	252	\|\| (demangled_name=SYMBOL_LINKAGE_NAME (minsym))==NULL
015a42b4 JB	253	\|\| !is_vtable_name (demangled_name))
	254	return NULL;
	255
	256	/* If we just skip the prefix, we get screwed by namespaces */
	257	demangled_name=cplus_demangle(demangled_name,DMGL_PARAMS\|DMGL_ANSI);
7d63ec12 MS	258	p = strchr (demangled_name, ' ');
	259	if (p)
	260	*p = '\0';
015a42b4 JB	261
015a42b4 JB	262	/* Lookup the type for the name */
362ff856 MC	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)
015a42b4 JB	266	return NULL;
	267
	268	if (TYPE_N_BASECLASSES(rtti_type) > 1 && full && (*full) != 1)
	269	{
	270	if (top)
	271	*top=TYPE_BASECLASS_BITPOS(rtti_type,TYPE_VPTR_FIELDNO(rtti_type))/8;
	272	if (top && ((*top) >0))
	273	{
	274	if (TYPE_LENGTH(rtti_type) > TYPE_LENGTH(known_type))
	275	{
	276	if (full)
	277	*full=0;
	278	}
	279	else
	280	{
	281	if (full)
	282	*full=1;
	283	}
	284	}
	285	}
	286	else
	287	{
	288	if (full)
	289	*full=1;
	290	}
015a42b4 JB	291
	292	return rtti_type;
	293	}
	294
1514d34e DJ	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. */
	297
	298	static int
	299	vb_match (struct type type, int index, struct type basetype)
	300	{
	301	struct type *fieldtype;
	302	char *name = TYPE_FIELD_NAME (type, index);
	303	char *field_class_name = NULL;
	304
	305	if (*name != '_')
	306	return 0;
	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;
	313
	314	if (field_class_name == NULL)
	315	/* This field is not a virtual base class pointer. */
	316	return 0;
	317
	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". */
	324	return 0;
	325
	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)
	331	return 1;
	332
	333	if (TYPE_NAME (basetype) != NULL
	334	&& TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL
bde58177 AC	335	&& strcmp (TYPE_NAME (basetype),
bde58177 AC	336	TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))) == 0)
1514d34e DJ	337	return 1;
	338	return 0;
	339	}
	340
	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.
	346
	347	-1 is returned on error. */
	348
	349	int
06c4d4dc AC	350	gnuv2_baseclass_offset (struct type *type, int index,
06c4d4dc AC	351	const bfd_byte *valaddr, CORE_ADDR address)
1514d34e DJ	352	{
	353	struct type *basetype = TYPE_BASECLASS (type, index);
	354
	355	if (BASETYPE_VIA_VIRTUAL (type, index))
	356	{
	357	/* Must hunt for the pointer to this virtual baseclass. */
aa1ee363 AC	358	int i, len = TYPE_NFIELDS (type);
aa1ee363 AC	359	int n_baseclasses = TYPE_N_BASECLASSES (type);
1514d34e DJ	360
	361	/* First look for the virtual baseclass pointer
	362	in the fields. */
	363	for (i = n_baseclasses; i < len; i++)
	364	{
	365	if (vb_match (type, i, basetype))
	366	{
	367	CORE_ADDR addr
	368	= unpack_pointer (TYPE_FIELD_TYPE (type, i),
	369	valaddr + (TYPE_FIELD_BITPOS (type, i) / 8));
	370
	371	return addr - (LONGEST) address;
	372	}
	373	}
	374	/* Not in the fields, so try looking through the baseclasses. */
	375	for (i = index + 1; i < n_baseclasses; i++)
	376	{
	377	int boffset =
	378	baseclass_offset (type, i, valaddr, address);
	379	if (boffset)
	380	return boffset;
	381	}
	382	/* Not found. */
	383	return -1;
	384	}
	385
	386	/* Baseclass is easily computed. */
	387	return TYPE_BASECLASS_BITPOS (type, index) / 8;
	388	}
015a42b4 JB	389
	390	static void
	391	init_gnuv2_ops (void)
	392	{
	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;
1514d34e	402	gnu_v2_abi_ops.baseclass_offset = gnuv2_baseclass_offset;
015a42b4 JB	403	}
015a42b4 JB	404
b9362cc7 AC	405	extern initialize_file_ftype _initialize_gnu_v2_abi; /* -Wmissing-prototypes */
b9362cc7 AC	406
015a42b4 JB	407	void
	408	_initialize_gnu_v2_abi (void)
	409	{
	410	init_gnuv2_ops ();
fe1f4a5e DJ	411	register_cp_abi (&gnu_v2_abi_ops);
fe1f4a5e DJ	412	set_cp_abi_as_auto_default (gnu_v2_abi_ops.shortname);
015a42b4	413	}