-/* 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. */
-value_ptr
-value_virtual_fn_field (value_ptr *arg1p, struct fn_field *f, int j,
- struct type *type, int offset)
-{
- value_ptr arg1 = *arg1p;
- struct type *type1 = check_typedef (VALUE_TYPE (arg1));
-
- if (TYPE_HAS_VTABLE (type))
- {
- /* Deal with HP/Taligent runtime model for virtual functions */
- value_ptr vp;
- value_ptr argp; /* arg1 cast to base */
- CORE_ADDR coreptr; /* pointer to target address */
- int class_index; /* which class segment pointer to use */
- struct type *ftype = TYPE_FN_FIELD_TYPE (f, j); /* method type */
-
- argp = value_cast (type, *arg1p);
-
- if (VALUE_ADDRESS (argp) == 0)
- error ("Address of object is null; object may not have been created.");
-
- /* pai: FIXME -- 32x64 possible problem? */
- /* First word (4 bytes) in object layout is the vtable pointer */
- coreptr = *(CORE_ADDR *) (VALUE_CONTENTS (argp)); /* pai: (temp) */
- /* + offset + VALUE_EMBEDDED_OFFSET (argp)); */
-
- if (!coreptr)
- error ("Virtual table pointer is null for object; object may not have been created.");
-
- /* pai/1997-05-09
- * FIXME: The code here currently handles only
- * the non-RRBC case of the Taligent/HP runtime spec; when RRBC
- * is introduced, the condition for the "if" below will have to
- * be changed to be a test for the RRBC case. */
-
- if (1)
- {
- /* Non-RRBC case; the virtual function pointers are stored at fixed
- * offsets in the virtual table. */
-
- /* Retrieve the offset in the virtual table from the debug
- * info. The offset of the vfunc's entry is in words from
- * the beginning of the vtable; but first we have to adjust
- * by HP_ACC_VFUNC_START to account for other entries */
-
- /* pai: FIXME: 32x64 problem here, a word may be 8 bytes in
- * which case the multiplier should be 8 and values should be long */
- vp = value_at (builtin_type_int,
- coreptr + 4 * (TYPE_FN_FIELD_VOFFSET (f, j) + HP_ACC_VFUNC_START), NULL);
-
- coreptr = *(CORE_ADDR *) (VALUE_CONTENTS (vp));
- /* coreptr now contains the address of the virtual function */
- /* (Actually, it contains the pointer to the plabel for the function. */
- }
- else
- {
- /* RRBC case; the virtual function pointers are found by double
- * indirection through the class segment tables. */
-
- /* Choose class segment depending on type we were passed */
- class_index = class_index_in_primary_list (type);
-
- /* Find class segment pointer. These are in the vtable slots after
- * some other entries, so adjust by HP_ACC_VFUNC_START for that. */
- /* pai: FIXME 32x64 problem here, if words are 8 bytes long
- * the multiplier below has to be 8 and value should be long. */
- vp = value_at (builtin_type_int,
- coreptr + 4 * (HP_ACC_VFUNC_START + class_index), NULL);
- /* Indirect once more, offset by function index */
- /* pai: FIXME 32x64 problem here, again multiplier could be 8 and value long */
- coreptr = *(CORE_ADDR *) (VALUE_CONTENTS (vp) + 4 * TYPE_FN_FIELD_VOFFSET (f, j));
- vp = value_at (builtin_type_int, coreptr, NULL);
- coreptr = *(CORE_ADDR *) (VALUE_CONTENTS (vp));
-
- /* coreptr now contains the address of the virtual function */
- /* (Actually, it contains the pointer to the plabel for the function.) */
-
- }
-
- if (!coreptr)
- error ("Address of virtual function is null; error in virtual table?");
-
- /* Wrap this addr in a value and return pointer */
- vp = allocate_value (ftype);
- VALUE_TYPE (vp) = ftype;
- VALUE_ADDRESS (vp) = coreptr;
-
- /* pai: (temp) do we need the value_ind stuff in value_fn_field? */
- return vp;
- }
- else
- { /* Not using HP/Taligent runtime conventions; so try to
- * use g++ conventions for virtual table */
-
- 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. */
- value_ptr entry, vfn, vtbl;
- value_ptr vi = value_from_longest (builtin_type_int,
- (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j));
- struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j);
- struct type *context;
- 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)
- {
- value_ptr tmp = value_cast (context, value_addr (arg1));
- VALUE_POINTED_TO_OFFSET (tmp) = 0;
- 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. */
- if (TYPE_VPTR_FIELDNO (context) < 0)
- fill_in_vptr_fieldno (context);
-
- /* 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, TYPE_VPTR_FIELDNO (context),
- TYPE_VPTR_BASETYPE (context));
-
- /* 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_add (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. */
- VALUE_OFFSET (arg1) += value_as_long (value_field (entry, 0));
-
- if (!VALUE_LAZY (arg1))
- {
- 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. */
- VALUE_TYPE (vfn) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j));
-
- *arg1p = arg1;
- return vfn;
- }
-}
-
-/* ARG is a pointer to an object we know to be at least
- a DTYPE. BTYPE is the most derived basetype that has
- already been searched (and need not be searched again).
- After looking at the vtables between BTYPE and DTYPE,
- return the most derived type we find. The caller must
- be satisfied when the return value == DTYPE.
-
- FIXME-tiemann: should work with dossier entries as well.
- NOTICE - djb: I see no good reason at all to keep this function now that
- we have RTTI support. It's used in literally one place, and it's
- hard to keep this function up to date when it's purpose is served
- by value_rtti_type efficiently.
- Consider it gone for 5.1. */
-
-static value_ptr
-value_headof (value_ptr in_arg, struct type *btype, struct type *dtype)
-{
- /* First collect the vtables we must look at for this object. */
- value_ptr arg, vtbl;
- struct symbol *sym;
- char *demangled_name;
- struct minimal_symbol *msymbol;
-
- btype = TYPE_VPTR_BASETYPE (dtype);
- CHECK_TYPEDEF (btype);
- arg = in_arg;
- if (btype != dtype)
- arg = value_cast (lookup_pointer_type (btype), arg);
- if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_REF)
- {
- /*
- * Copy the value, but change the type from (T&) to (T*).
- * We keep the same location information, which is efficient,
- * and allows &(&X) to get the location containing the reference.
- */
- arg = value_copy (arg);
- VALUE_TYPE (arg) = lookup_pointer_type (TYPE_TARGET_TYPE (VALUE_TYPE (arg)));
- }
- if (VALUE_ADDRESS(value_field (value_ind(arg), TYPE_VPTR_FIELDNO (btype)))==0)
- return arg;
-
- vtbl = value_ind (value_field (value_ind (arg), TYPE_VPTR_FIELDNO (btype)));
- /* Turn vtable into typeinfo function */
- VALUE_OFFSET(vtbl)+=4;
-
- msymbol = lookup_minimal_symbol_by_pc ( value_as_pointer(value_ind(vtbl)) );
- if (msymbol == NULL
- || (demangled_name = SYMBOL_NAME (msymbol)) == NULL)
- {
- /* If we expected to find a vtable, but did not, let the user
- know that we aren't happy, but don't throw an error.
- FIXME: there has to be a better way to do this. */
- struct type *error_type = (struct type *) xmalloc (sizeof (struct type));
- memcpy (error_type, VALUE_TYPE (in_arg), sizeof (struct type));
- TYPE_NAME (error_type) = savestring ("suspicious *", sizeof ("suspicious *"));
- VALUE_TYPE (in_arg) = error_type;
- return in_arg;
- }
- demangled_name = cplus_demangle(demangled_name,DMGL_ANSI);
- *(strchr (demangled_name, ' ')) = '\0';
-
- sym = lookup_symbol (demangled_name, 0, VAR_NAMESPACE, 0, 0);
- if (sym == NULL)
- error ("could not find type declaration for `%s'", demangled_name);
-
- arg = in_arg;
- VALUE_TYPE (arg) = lookup_pointer_type (SYMBOL_TYPE (sym));
- return arg;
-}
-
-/* ARG is a pointer object of type TYPE. If TYPE has virtual
- function tables, probe ARG's tables (including the vtables
- of its baseclasses) to figure out the most derived type that ARG
- could actually be a pointer to. */
-
-value_ptr
-value_from_vtable_info (value_ptr arg, struct type *type)
-{
- /* Take care of preliminaries. */
- if (TYPE_VPTR_FIELDNO (type) < 0)
- fill_in_vptr_fieldno (type);
- if (TYPE_VPTR_FIELDNO (type) < 0)
- return 0;
-
- return value_headof (arg, 0, 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
- && STREQ (TYPE_NAME (basetype),
- TYPE_NAME (TYPE_TARGET_TYPE (fieldtype))))
- 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
-baseclass_offset (struct type *type, int index, char *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. */
- register int i, len = TYPE_NFIELDS (type);
- register 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;
-}