gdb/extension.h

   1 /* Interface between gdb and its extension languages.
   2
   3    Copyright (C) 2014-2018 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef EXTENSION_H
  21 #define EXTENSION_H
  22
  23 #include "mi/mi-cmds.h" /* For PRINT_NO_VALUES, etc.  */
  24 #include "common/vec.h"
  25
  26 struct breakpoint;
  27 struct command_line;
  28 struct frame_info;
  29 struct language_defn;
  30 struct objfile;
  31 struct extension_language_defn;
  32 struct type;
  33 struct ui_file;
  34 struct ui_out;
  35 struct value;
  36 struct value_print_options;
  37
  38 /* A function to load and process a script file.
  39    The file has been opened and is ready to be read from the beginning.
  40    Any exceptions are not caught, and are passed to the caller.  */
  41 typedef void script_sourcer_func (const struct extension_language_defn *,
  42                                   FILE *stream, const char *filename);
  43
  44 /* A function to load and process a script for an objfile.
  45    The file has been opened and is ready to be read from the beginning.
  46    Any exceptions are not caught, and are passed to the caller.  */
  47 typedef void objfile_script_sourcer_func
  48   (const struct extension_language_defn *,
  49    struct objfile *, FILE *stream, const char *filename);
  50
  51 /* A function to execute a script for an objfile.
  52    Any exceptions are not caught, and are passed to the caller.  */
  53 typedef void objfile_script_executor_func
  54   (const struct extension_language_defn *,
  55    struct objfile *, const char *name, const char *script);
  56
  57 /* Enum of each extension(/scripting) language.  */
  58
  59 enum extension_language
  60   {
  61     EXT_LANG_NONE,
  62     EXT_LANG_GDB,
  63     EXT_LANG_PYTHON,
  64     EXT_LANG_GUILE
  65   };
  66
  67 /* Extension language frame-filter status return values.  */
  68
  69 enum ext_lang_bt_status
  70   {
  71     /* Return when an error has occurred in processing frame filters,
  72        or when printing the stack.  */
  73     EXT_LANG_BT_ERROR = -1,
  74
  75     /* Return from internal routines to indicate that the function
  76        succeeded.  */
  77     EXT_LANG_BT_OK = 1,
  78
  79     /* Return when the frame filter process is complete, and all
  80        operations have succeeded.  */
  81     EXT_LANG_BT_COMPLETED = 2,
  82
  83     /* Return when the frame filter process is complete, but there
  84        were no filter registered and enabled to process.  */
  85     EXT_LANG_BT_NO_FILTERS = 3
  86   };
  87
  88 /* Flags to pass to apply_extlang_frame_filter.  */
  89
  90 enum frame_filter_flags
  91   {
  92     /* Set this flag if frame level is to be printed.  */
  93     PRINT_LEVEL = 1,
  94
  95     /* Set this flag if frame information is to be printed.  */
  96     PRINT_FRAME_INFO = 2,
  97
  98     /* Set this flag if frame arguments are to be printed.  */
  99     PRINT_ARGS = 4,
 100
 101     /* Set this flag if frame locals are to be printed.  */
 102     PRINT_LOCALS = 8,
 103   };
 104
 105 /* A choice of the different frame argument printing strategies that
 106    can occur in different cases of frame filter instantiation.  */
 107
 108 enum ext_lang_frame_args
 109   {
 110     /* Print no values for arguments when invoked from the MI. */
 111     NO_VALUES = PRINT_NO_VALUES,
 112
 113     MI_PRINT_ALL_VALUES = PRINT_ALL_VALUES,
 114
 115     /* Print only simple values (what MI defines as "simple") for
 116        arguments when invoked from the MI. */
 117     MI_PRINT_SIMPLE_VALUES = PRINT_SIMPLE_VALUES,
 118
 119     /* Print only scalar values for arguments when invoked from the CLI. */
 120     CLI_SCALAR_VALUES,
 121
 122     /* Print all values for arguments when invoked from the CLI. */
 123     CLI_ALL_VALUES
 124   };
 125
 126 /* The possible results of
 127    extension_language_ops.breakpoint_cond_says_stop.  */
 128
 129 enum ext_lang_bp_stop
 130   {
 131     /* No "stop" condition is set.  */
 132     EXT_LANG_BP_STOP_UNSET,
 133
 134     /* A "stop" condition is set, and it says "don't stop".  */
 135     EXT_LANG_BP_STOP_NO,
 136
 137     /* A "stop" condition is set, and it says "stop".  */
 138     EXT_LANG_BP_STOP_YES
 139   };
 140
 141 /* Table of type printers associated with the global typedef table.  */
 142
 143 struct ext_lang_type_printers
 144 {
 145   /* Type-printers from Python.  */
 146   void *py_type_printers;
 147 };
 148
 149 /* The return code for some API calls.  */
 150
 151 enum ext_lang_rc
 152 {
 153   /* The operation completed successfully.  */
 154   EXT_LANG_RC_OK,
 155
 156   /* The operation was not performed (e.g., no pretty-printer).  */
 157   EXT_LANG_RC_NOP,
 158
 159   /* There was an error (e.g., Python error while printing a value).
 160      When an error occurs no further extension languages are tried.
 161      This is to preserve existing behaviour, and because it's convenient
 162      for Python developers.
 163      Note: This is different than encountering a memory error trying to read
 164      a value for pretty-printing.  Here we're referring to, e.g., programming
 165      errors that trigger an exception in the extension language.  */
 166   EXT_LANG_RC_ERROR
 167 };
 168
 169 /* A type which holds its extension language specific xmethod worker data.  */
 170
 171 struct xmethod_worker
 172 {
 173   xmethod_worker (const extension_language_defn *extlang)
 174   : m_extlang (extlang)
 175   {}
 176
 177   virtual ~xmethod_worker () = default;
 178
 179   /* Invoke the xmethod encapsulated in this worker and return the result.
 180      The method is invoked on OBJ with arguments in the ARGS array.  NARGS is
 181      the length of the this array.  */
 182
 183   virtual value *invoke (value *obj, value **args, int nargs) = 0;
 184
 185   /* Clone this worker, returns a new but identical worker.
 186      The function get_matching_xmethod_workers returns a vector of matching
 187      workers.  If a particular worker is selected by GDB to invoke a method,
 188      then this function can help in cloning the selected worker.  */
 189
 190   virtual std::unique_ptr<xmethod_worker> clone () = 0;
 191
 192   /* Return the arg types of the xmethod encapsulated in this worker.
 193      An array of arg types is returned.  The length of the array is returned in
 194      NARGS.  The type of the 'this' object is returned as the first element of
 195      array.  */
 196
 197   type **get_arg_types (int *nargs);
 198
 199   /* Return the type of the result of the xmethod encapsulated in this worker.
 200      OBJECT, ARGS, NARGS are the same as for invoke.  */
 201
 202   type *get_result_type (value *object, value **args, int nargs);
 203
 204 private:
 205
 206   /* Return the types of the arguments the method takes.  The number of
 207      arguments is returned in NARGS, and their types are returned in the array
 208      ARGTYPES.  */
 209
 210   virtual enum ext_lang_rc do_get_arg_types
 211     (int *nargs, struct type ***arg_types) = 0;
 212
 213   /* Fetch the type of the result of the method implemented by this worker.
 214      OBJECT, ARGS, NARGS are the same as for the invoked method.  The result
 215      type is stored in *RESULT_TYPE.  */
 216
 217   virtual enum ext_lang_rc do_get_result_type
 218     (struct value *obj, struct value **args, int nargs,
 219      struct type **result_type_ptr) = 0;
 220
 221   /* The language the xmethod worker is implemented in.  */
 222
 223   const extension_language_defn *m_extlang;
 224 };
 225
 226 typedef std::unique_ptr<xmethod_worker> xmethod_worker_up;
 227
 228 /* The interface for gdb's own extension(/scripting) language.  */
 229 extern const struct extension_language_defn extension_language_gdb;
 230
 231 extern const struct extension_language_defn *get_ext_lang_defn
 232   (enum extension_language lang);
 233
 234 extern const struct extension_language_defn *get_ext_lang_of_file
 235   (const char *file);
 236
 237 extern int ext_lang_present_p (const struct extension_language_defn *);
 238
 239 extern int ext_lang_initialized_p (const struct extension_language_defn *);
 240
 241 extern void throw_ext_lang_unsupported
 242   (const struct extension_language_defn *);
 243
 244 /* Accessors for "public" attributes of the extension language definition.  */
 245
 246 extern enum extension_language ext_lang_kind
 247   (const struct extension_language_defn *);
 248
 249 extern const char *ext_lang_name (const struct extension_language_defn *);
 250
 251 extern const char *ext_lang_capitalized_name
 252   (const struct extension_language_defn *);
 253
 254 extern const char *ext_lang_suffix (const struct extension_language_defn *);
 255
 256 extern const char *ext_lang_auto_load_suffix
 257   (const struct extension_language_defn *);
 258
 259 extern script_sourcer_func *ext_lang_script_sourcer
 260   (const struct extension_language_defn *);
 261
 262 extern objfile_script_sourcer_func *ext_lang_objfile_script_sourcer
 263   (const struct extension_language_defn *);
 264
 265 extern objfile_script_executor_func *ext_lang_objfile_script_executor
 266   (const struct extension_language_defn *);
 267
 268 extern int ext_lang_auto_load_enabled (const struct extension_language_defn *);
 269
 270 /* Wrappers for each extension language API function that iterate over all
 271    extension languages.  */
 272
 273 extern void finish_ext_lang_initialization (void);
 274
 275 extern void eval_ext_lang_from_control_command (struct command_line *cmd);
 276
 277 extern void auto_load_ext_lang_scripts_for_objfile (struct objfile *);
 278
 279 extern struct ext_lang_type_printers *start_ext_lang_type_printers (void);
 280
 281 extern char *apply_ext_lang_type_printers (struct ext_lang_type_printers *,
 282                                            struct type *);
 283
 284 extern void free_ext_lang_type_printers (struct ext_lang_type_printers *);
 285
 286 extern int apply_ext_lang_val_pretty_printer
 287   (struct type *type,
 288    LONGEST embedded_offset, CORE_ADDR address,
 289    struct ui_file *stream, int recurse,
 290    struct value *val, const struct value_print_options *options,
 291    const struct language_defn *language);
 292
 293 extern enum ext_lang_bt_status apply_ext_lang_frame_filter
 294   (struct frame_info *frame, int flags, enum ext_lang_frame_args args_type,
 295    struct ui_out *out, int frame_low, int frame_high);
 296
 297 extern void preserve_ext_lang_values (struct objfile *, htab_t copied_types);
 298
 299 extern const struct extension_language_defn *get_breakpoint_cond_ext_lang
 300   (struct breakpoint *b, enum extension_language skip_lang);
 301
 302 extern int breakpoint_ext_lang_cond_says_stop (struct breakpoint *);
 303
 304 /* If a method with name METHOD_NAME is to be invoked on an object of type
 305    TYPE, then all extension languages are searched for implementations of
 306    methods with name METHOD_NAME.  All matches found are appended to the WORKERS
 307    vector.  */
 308
 309 extern void get_matching_xmethod_workers
 310   (struct type *type, const char *method_name,
 311    std::vector<xmethod_worker_up> *workers);
 312
 313 #endif /* EXTENSION_H */