gdb/cp-abi.h

   1 /* Abstraction of various C++ ABI's we support, and the info we need
   2    to get from them.
   3
   4    Contributed by Daniel Berlin <dberlin@redhat.com>
   5
   6    Copyright (C) 2001-2020 Free Software Foundation, Inc.
   7
   8    This file is part of GDB.
   9
  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
  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
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  22
  23 #ifndef CP_ABI_H
  24 #define CP_ABI_H
  25
  26 struct fn_field;
  27 struct type;
  28 struct value;
  29 struct ui_file;
  30 struct frame_info;
  31
  32 /* The functions here that attempt to determine what sort of thing a
  33    mangled name refers to may well be revised in the future.  It would
  34    certainly be cleaner to carry this information explicitly in GDB's
  35    data structures than to derive it from the mangled name.  */
  36
  37
  38 /* Kinds of constructors.  All these values are guaranteed to be
  39    non-zero.  */
  40 enum ctor_kinds {
  41
  42   /* Initialize a complete object, including virtual bases, using
  43      memory provided by caller.  */
  44   complete_object_ctor = 1,
  45
  46   /* Initialize a base object of some larger object.  */
  47   base_object_ctor,
  48
  49   /* An allocating complete-object constructor.  */
  50   complete_object_allocating_ctor
  51 };
  52
  53 /* Return non-zero iff NAME is the mangled name of a constructor.
  54    Actually, return an `enum ctor_kind' value describing what *kind*
  55    of constructor it is.  */
  56 extern enum ctor_kinds is_constructor_name (const char *name);
  57
  58
  59 /* Kinds of destructors.  All these values are guaranteed to be
  60    non-zero.  */
  61 enum dtor_kinds {
  62
  63   /* A destructor which finalizes the entire object, and then calls
  64      `delete' on its storage.  */
  65   deleting_dtor = 1,
  66
  67   /* A destructor which finalizes the entire object, but does not call
  68      `delete'.  */
  69   complete_object_dtor,
  70
  71   /* A destructor which finalizes a subobject of some larger
  72      object.  */
  73   base_object_dtor
  74 };
  75
  76 /* Return non-zero iff NAME is the mangled name of a destructor.
  77    Actually, return an `enum dtor_kind' value describing what *kind*
  78    of destructor it is.  */
  79 extern enum dtor_kinds is_destructor_name (const char *name);
  80
  81
  82 /* Return non-zero iff NAME is the mangled name of a vtable.  */
  83 extern int is_vtable_name (const char *name);
  84
  85
  86 /* Return non-zero iff NAME is the un-mangled name of an operator,
  87    perhaps scoped within some class.  */
  88 extern int is_operator_name (const char *name);
  89
  90
  91 /* Return an object's virtual function as a value.
  92
  93    VALUEP is a pointer to a pointer to a value, holding the object
  94    whose virtual function we want to invoke.  If the ABI requires a
  95    virtual function's caller to adjust the `this' pointer by an amount
  96    retrieved from the vtable before invoking the function (i.e., we're
  97    not using "vtable thunks" to do the adjustment automatically), then
  98    this function may set *VALUEP to point to a new object with an
  99    appropriately tweaked address.
 100
 101    The J'th element of the overload set F is the virtual function of
 102    *VALUEP we want to invoke.
 103
 104    TYPE is the base type of *VALUEP whose method we're invoking ---
 105    this is the type containing F.  OFFSET is the offset of that base
 106    type within *VALUEP.  */
 107 extern struct value *value_virtual_fn_field (struct value **valuep,
 108                                              struct fn_field *f,
 109                                              int j,
 110                                              struct type *type,
 111                                              int offset);
 112
 113
 114 /* Try to find the run-time type of VALUE, using C++ run-time type
 115    information.  Return the run-time type, or zero if we can't figure
 116    it out.
 117
 118    If we do find the run-time type:
 119    - Set *FULL to non-zero if VALUE already contains the complete
 120      run-time object, not just some embedded base class of the object.
 121    - Set *TOP and *USING_ENC to indicate where the enclosing object
 122      starts relative to VALUE:
 123      - If *USING_ENC is zero, then *TOP is the offset from the start
 124        of the complete object to the start of the embedded subobject
 125        VALUE represents.  In other words, the enclosing object starts
 126        at VALUE_ADDR (VALUE) + VALUE_OFFSET (VALUE) +
 127        value_embedded_offset (VALUE) + *TOP
 128      - If *USING_ENC is non-zero, then *TOP is the offset from the
 129        address of the complete object to the enclosing object stored
 130        in VALUE.  In other words, the enclosing object starts at
 131        VALUE_ADDR (VALUE) + VALUE_OFFSET (VALUE) + *TOP.
 132      If VALUE's type and enclosing type are the same, then these two
 133      cases are equivalent.
 134
 135    FULL, TOP, and USING_ENC can each be zero, in which case we don't
 136    provide the corresponding piece of information.  */
 137 extern struct type *value_rtti_type (struct value *value,
 138                                      int *full, LONGEST *top,
 139                                      int *using_enc);
 140
 141 /* Compute the offset of the baseclass which is the INDEXth baseclass
 142    of class TYPE, for value at VALADDR (in host) at ADDRESS (in
 143    target), offset by EMBEDDED_OFFSET.  VALADDR points to the raw
 144    contents of VAL.  The result is the offset of the baseclass value
 145    relative to (the address of)(ARG) + OFFSET.  */
 146
 147 extern int baseclass_offset (struct type *type,
 148                              int index, const gdb_byte *valaddr,
 149                              LONGEST embedded_offset,
 150                              CORE_ADDR address,
 151                              const struct value *val);
 152
 153 /* Describe the target of a pointer to method.  CONTENTS is the byte
 154    pattern representing the pointer to method.  TYPE is the pointer to
 155    method type.  STREAM is the stream to print it to.  */
 156 void cplus_print_method_ptr (const gdb_byte *contents,
 157                              struct type *type,
 158                              struct ui_file *stream);
 159
 160 /* Return the size of a pointer to member function of type
 161    TO_TYPE.  */
 162 int cplus_method_ptr_size (struct type *to_type);
 163
 164 /* Return the method which should be called by applying METHOD_PTR to
 165    *THIS_P, and adjust *THIS_P if necessary.  */
 166 struct value *cplus_method_ptr_to_value (struct value **this_p,
 167                                          struct value *method_ptr);
 168
 169 /* Create the byte pattern in CONTENTS representing a pointer of type
 170    TYPE to member function at ADDRESS (if IS_VIRTUAL is 0) or with
 171    virtual table offset ADDRESS (if IS_VIRTUAL is 1).  This is the
 172    opposite of cplus_method_ptr_to_value.  */
 173 void cplus_make_method_ptr (struct type *type, gdb_byte *CONTENTS,
 174                             CORE_ADDR address, int is_virtual);
 175
 176 /* Print the vtable for VALUE, if there is one.  If there is no
 177    vtable, print a message, but do not throw.  */
 178
 179 void cplus_print_vtable (struct value *value);
 180
 181 /* Implement 'typeid': find the type info for VALUE, if possible.  If
 182    the type info cannot be found, throw an exception.  */
 183
 184 extern struct value *cplus_typeid (struct value *value);
 185
 186 /* Return the type of 'typeid' for the current C++ ABI on the given
 187    architecture.  */
 188
 189 extern struct type *cplus_typeid_type (struct gdbarch *gdbarch);
 190
 191 /* Given a value which holds a pointer to a std::type_info, return the
 192    type which that type_info represents.  Throw an exception if the
 193    type cannot be found.  */
 194
 195 extern struct type *cplus_type_from_type_info (struct value *value);
 196
 197 /* Given a value which holds a pointer to a std::type_info, return the
 198    name of the type which that type_info represents.  Throw an
 199    exception if the type name cannot be found.  */
 200
 201 extern std::string cplus_typename_from_type_info (struct value *value);
 202
 203 /* Determine if we are currently in a C++ thunk.  If so, get the
 204    address of the routine we are thunking to and continue to there
 205    instead.  */
 206
 207 CORE_ADDR cplus_skip_trampoline (struct frame_info *frame,
 208                                  CORE_ADDR stop_pc);
 209
 210 /* Return a struct that provides pass-by-reference information
 211    about the given TYPE.  */
 212
 213 extern struct language_pass_by_ref_info cp_pass_by_reference
 214   (struct type *type);
 215
 216 struct cp_abi_ops
 217 {
 218   const char *shortname;
 219   const char *longname;
 220   const char *doc;
 221
 222   /* ABI-specific implementations for the functions declared
 223      above.  */
 224   enum ctor_kinds (*is_constructor_name) (const char *name);
 225   enum dtor_kinds (*is_destructor_name) (const char *name);
 226   int (*is_vtable_name) (const char *name);
 227   int (*is_operator_name) (const char *name);
 228   struct value *(*virtual_fn_field) (struct value **arg1p,
 229                                      struct fn_field * f,
 230                                      int j, struct type * type,
 231                                      int offset);
 232   struct type *(*rtti_type) (struct value *v, int *full,
 233                              LONGEST *top, int *using_enc);
 234   int (*baseclass_offset) (struct type *type, int index,
 235                            const bfd_byte *valaddr, LONGEST embedded_offset,
 236                            CORE_ADDR address, const struct value *val);
 237   void (*print_method_ptr) (const gdb_byte *contents,
 238                             struct type *type,
 239                             struct ui_file *stream);
 240   int (*method_ptr_size) (struct type *);
 241   void (*make_method_ptr) (struct type *, gdb_byte *,
 242                            CORE_ADDR, int);
 243   struct value * (*method_ptr_to_value) (struct value **,
 244                                          struct value *);
 245   void (*print_vtable) (struct value *);
 246   struct value *(*get_typeid) (struct value *value);
 247   struct type *(*get_typeid_type) (struct gdbarch *gdbarch);
 248   struct type *(*get_type_from_type_info) (struct value *value);
 249   std::string (*get_typename_from_type_info) (struct value *value);
 250   CORE_ADDR (*skip_trampoline) (struct frame_info *, CORE_ADDR);
 251   struct language_pass_by_ref_info (*pass_by_reference) (struct type *type);
 252 };
 253
 254
 255 extern int register_cp_abi (struct cp_abi_ops *abi);
 256 extern void set_cp_abi_as_auto_default (const char *short_name);
 257
 258 #endif /* CP_ABI_H */