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8480a37e14
We currently pass frames to function by value, as `frame_info_ptr`.
This is somewhat expensive:
- the size of `frame_info_ptr` is 64 bytes, which is a bit big to pass
by value
- the constructors and destructor link/unlink the object in the global
`frame_info_ptr::frame_list` list. This is an `intrusive_list`, so
it's not so bad: it's just assigning a few points, there's no memory
allocation as if it was `std::list`, but still it's useless to do
that over and over.
As suggested by Tom Tromey, change many function signatures to accept
`const frame_info_ptr &` instead of `frame_info_ptr`.
Some functions reassign their `frame_info_ptr` parameter, like:
void
the_func (frame_info_ptr frame)
{
for (; frame != nullptr; frame = get_prev_frame (frame))
{
...
}
}
I wondered what to do about them, do I leave them as-is or change them
(and need to introduce a separate local variable that can be
re-assigned). I opted for the later for consistency. It might not be
clear why some functions take `const frame_info_ptr &` while others take
`frame_info_ptr`. Also, if a function took a `frame_info_ptr` because
it did re-assign its parameter, I doubt that we would think to change it
to `const frame_info_ptr &` should the implementation change such that
it doesn't need to take `frame_info_ptr` anymore. It seems better to
have a simple rule and apply it everywhere.
Change-Id: I59d10addef687d157f82ccf4d54f5dde9a963fd0
Approved-By: Andrew Burgess <aburgess@redhat.com>
259 lines
9.5 KiB
C++
259 lines
9.5 KiB
C++
/* Abstraction of various C++ ABI's we support, and the info we need
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to get from them.
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Contributed by Daniel Berlin <dberlin@redhat.com>
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Copyright (C) 2001-2024 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef CP_ABI_H
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#define CP_ABI_H
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struct fn_field;
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struct type;
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struct value;
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struct ui_file;
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class frame_info_ptr;
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/* The functions here that attempt to determine what sort of thing a
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mangled name refers to may well be revised in the future. It would
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certainly be cleaner to carry this information explicitly in GDB's
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data structures than to derive it from the mangled name. */
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/* Kinds of constructors. All these values are guaranteed to be
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non-zero. */
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enum ctor_kinds {
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/* Initialize a complete object, including virtual bases, using
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memory provided by caller. */
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complete_object_ctor = 1,
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/* Initialize a base object of some larger object. */
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base_object_ctor,
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/* An allocating complete-object constructor. */
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complete_object_allocating_ctor
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};
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/* Return non-zero iff NAME is the mangled name of a constructor.
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Actually, return an `enum ctor_kind' value describing what *kind*
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of constructor it is. */
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extern enum ctor_kinds is_constructor_name (const char *name);
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/* Kinds of destructors. All these values are guaranteed to be
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non-zero. */
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enum dtor_kinds {
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/* A destructor which finalizes the entire object, and then calls
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`delete' on its storage. */
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deleting_dtor = 1,
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/* A destructor which finalizes the entire object, but does not call
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`delete'. */
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complete_object_dtor,
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/* A destructor which finalizes a subobject of some larger
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object. */
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base_object_dtor
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};
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/* Return non-zero iff NAME is the mangled name of a destructor.
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Actually, return an `enum dtor_kind' value describing what *kind*
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of destructor it is. */
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extern enum dtor_kinds is_destructor_name (const char *name);
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/* Return non-zero iff NAME is the mangled name of a vtable. */
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extern int is_vtable_name (const char *name);
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/* Return non-zero iff NAME is the un-mangled name of an operator,
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perhaps scoped within some class. */
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extern int is_operator_name (const char *name);
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/* Return an object's virtual function as a value.
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VALUEP is a pointer to a pointer to a value, holding the object
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whose virtual function we want to invoke. If the ABI requires a
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virtual function's caller to adjust the `this' pointer by an amount
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retrieved from the vtable before invoking the function (i.e., we're
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not using "vtable thunks" to do the adjustment automatically), then
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this function may set *VALUEP to point to a new object with an
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appropriately tweaked address.
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The J'th element of the overload set F is the virtual function of
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*VALUEP we want to invoke.
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TYPE is the base type of *VALUEP whose method we're invoking ---
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this is the type containing F. OFFSET is the offset of that base
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type within *VALUEP. */
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extern struct value *value_virtual_fn_field (struct value **valuep,
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struct fn_field *f,
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int j,
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struct type *type,
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int offset);
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/* Try to find the run-time type of VALUE, using C++ run-time type
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information. Return the run-time type, or zero if we can't figure
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it out.
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If we do find the run-time type:
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- Set *FULL to non-zero if VALUE already contains the complete
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run-time object, not just some embedded base class of the object.
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- Set *TOP and *USING_ENC to indicate where the enclosing object
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starts relative to VALUE:
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- If *USING_ENC is zero, then *TOP is the offset from the start
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of the complete object to the start of the embedded subobject
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VALUE represents. In other words, the enclosing object starts
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at VALUE_ADDR (VALUE) + VALUE->offset () +
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VALUE->embedded_offset () + *TOP
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- If *USING_ENC is non-zero, then *TOP is the offset from the
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address of the complete object to the enclosing object stored
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in VALUE. In other words, the enclosing object starts at
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VALUE_ADDR (VALUE) + VALUE->offset () + *TOP.
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If VALUE's type and enclosing type are the same, then these two
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cases are equivalent.
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FULL, TOP, and USING_ENC can each be zero, in which case we don't
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provide the corresponding piece of information. */
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extern struct type *value_rtti_type (struct value *value,
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int *full, LONGEST *top,
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int *using_enc);
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/* Compute the offset of the baseclass which is the INDEXth baseclass
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of class TYPE, for value at VALADDR (in host) at ADDRESS (in
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target), offset by EMBEDDED_OFFSET. VALADDR points to the raw
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contents of VAL. The result is the offset of the baseclass value
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relative to (the address of)(ARG) + OFFSET. */
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extern int baseclass_offset (struct type *type,
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int index, const gdb_byte *valaddr,
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LONGEST embedded_offset,
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CORE_ADDR address,
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const struct value *val);
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/* Describe the target of a pointer to method. CONTENTS is the byte
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pattern representing the pointer to method. TYPE is the pointer to
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method type. STREAM is the stream to print it to. */
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void cplus_print_method_ptr (const gdb_byte *contents,
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struct type *type,
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struct ui_file *stream);
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/* Return the size of a pointer to member function of type
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TO_TYPE. */
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int cplus_method_ptr_size (struct type *to_type);
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/* Return the method which should be called by applying METHOD_PTR to
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*THIS_P, and adjust *THIS_P if necessary. */
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struct value *cplus_method_ptr_to_value (struct value **this_p,
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struct value *method_ptr);
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/* Create the byte pattern in CONTENTS representing a pointer of type
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TYPE to member function at ADDRESS (if IS_VIRTUAL is 0) or with
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virtual table offset ADDRESS (if IS_VIRTUAL is 1). This is the
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opposite of cplus_method_ptr_to_value. */
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void cplus_make_method_ptr (struct type *type, gdb_byte *CONTENTS,
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CORE_ADDR address, int is_virtual);
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/* Print the vtable for VALUE, if there is one. If there is no
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vtable, print a message, but do not throw. */
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void cplus_print_vtable (struct value *value);
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/* Implement 'typeid': find the type info for VALUE, if possible. If
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the type info cannot be found, throw an exception. */
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extern struct value *cplus_typeid (struct value *value);
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/* Return the type of 'typeid' for the current C++ ABI on the given
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architecture. */
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extern struct type *cplus_typeid_type (struct gdbarch *gdbarch);
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/* Given a value which holds a pointer to a std::type_info, return the
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type which that type_info represents. Throw an exception if the
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type cannot be found. */
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extern struct type *cplus_type_from_type_info (struct value *value);
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/* Given a value which holds a pointer to a std::type_info, return the
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name of the type which that type_info represents. Throw an
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exception if the type name cannot be found. */
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extern std::string cplus_typename_from_type_info (struct value *value);
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/* Determine if we are currently in a C++ thunk. If so, get the
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address of the routine we are thunking to and continue to there
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instead. */
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CORE_ADDR cplus_skip_trampoline (const frame_info_ptr &frame,
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CORE_ADDR stop_pc);
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/* Return a struct that provides pass-by-reference information
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about the given TYPE. */
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extern struct language_pass_by_ref_info cp_pass_by_reference
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(struct type *type);
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struct cp_abi_ops
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{
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const char *shortname;
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const char *longname;
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const char *doc;
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/* ABI-specific implementations for the functions declared
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above. */
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enum ctor_kinds (*is_constructor_name) (const char *name);
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enum dtor_kinds (*is_destructor_name) (const char *name);
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int (*is_vtable_name) (const char *name);
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int (*is_operator_name) (const char *name);
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struct value *(*virtual_fn_field) (struct value **arg1p,
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struct fn_field * f,
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int j, struct type * type,
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int offset);
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struct type *(*rtti_type) (struct value *v, int *full,
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LONGEST *top, int *using_enc);
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int (*baseclass_offset) (struct type *type, int index,
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const bfd_byte *valaddr, LONGEST embedded_offset,
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CORE_ADDR address, const struct value *val);
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void (*print_method_ptr) (const gdb_byte *contents,
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struct type *type,
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struct ui_file *stream);
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int (*method_ptr_size) (struct type *);
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void (*make_method_ptr) (struct type *, gdb_byte *,
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CORE_ADDR, int);
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struct value * (*method_ptr_to_value) (struct value **,
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struct value *);
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void (*print_vtable) (struct value *);
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struct value *(*get_typeid) (struct value *value);
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struct type *(*get_typeid_type) (struct gdbarch *gdbarch);
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struct type *(*get_type_from_type_info) (struct value *value);
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std::string (*get_typename_from_type_info) (struct value *value);
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CORE_ADDR (*skip_trampoline) (const frame_info_ptr &, CORE_ADDR);
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struct language_pass_by_ref_info (*pass_by_reference) (struct type *type);
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};
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extern int register_cp_abi (struct cp_abi_ops *abi);
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extern void set_cp_abi_as_auto_default (const char *short_name);
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#endif /* CP_ABI_H */
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