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     /* Set this flag if a "More frames" message is to be printed.  */
 105     PRINT_MORE_FRAMES = 16,
 106   };
 107
 108 /* A choice of the different frame argument printing strategies that
 109    can occur in different cases of frame filter instantiation.  */
 110
 111 enum ext_lang_frame_args
 112   {
 113     /* Print no values for arguments when invoked from the MI. */
 114     NO_VALUES = PRINT_NO_VALUES,
 115
 116     MI_PRINT_ALL_VALUES = PRINT_ALL_VALUES,
 117
 118     /* Print only simple values (what MI defines as "simple") for
 119        arguments when invoked from the MI. */
 120     MI_PRINT_SIMPLE_VALUES = PRINT_SIMPLE_VALUES,
 121
 122     /* Print only scalar values for arguments when invoked from the CLI. */
 123     CLI_SCALAR_VALUES,
 124
 125     /* Print all values for arguments when invoked from the CLI. */
 126     CLI_ALL_VALUES
 127   };
 128
 129 /* The possible results of
 130    extension_language_ops.breakpoint_cond_says_stop.  */
 131
 132 enum ext_lang_bp_stop
 133   {
 134     /* No "stop" condition is set.  */
 135     EXT_LANG_BP_STOP_UNSET,
 136
 137     /* A "stop" condition is set, and it says "don't stop".  */
 138     EXT_LANG_BP_STOP_NO,
 139
 140     /* A "stop" condition is set, and it says "stop".  */
 141     EXT_LANG_BP_STOP_YES
 142   };
 143
 144 /* Table of type printers associated with the global typedef table.  */
 145
 146 struct ext_lang_type_printers
 147 {
 148   /* Type-printers from Python.  */
 149   void *py_type_printers;
 150 };
 151
 152 /* The return code for some API calls.  */
 153
 154 enum ext_lang_rc
 155 {
 156   /* The operation completed successfully.  */
 157   EXT_LANG_RC_OK,
 158
 159   /* The operation was not performed (e.g., no pretty-printer).  */
 160   EXT_LANG_RC_NOP,
 161
 162   /* There was an error (e.g., Python error while printing a value).
 163      When an error occurs no further extension languages are tried.
 164      This is to preserve existing behaviour, and because it's convenient
 165      for Python developers.
 166      Note: This is different than encountering a memory error trying to read
 167      a value for pretty-printing.  Here we're referring to, e.g., programming
 168      errors that trigger an exception in the extension language.  */
 169   EXT_LANG_RC_ERROR
 170 };
 171
 172 /* A type which holds its extension language specific xmethod worker data.  */
 173
 174 struct xmethod_worker
 175 {
 176   xmethod_worker (const extension_language_defn *extlang)
 177   : m_extlang (extlang)
 178   {}
 179
 180   virtual ~xmethod_worker () = default;
 181
 182   /* Invoke the xmethod encapsulated in this worker and return the result.
 183      The method is invoked on OBJ with arguments in the ARGS array.  NARGS is
 184      the length of the this array.  */
 185
 186   virtual value *invoke (value *obj, value **args, int nargs) = 0;
 187
 188   /* Return the arg types of the xmethod encapsulated in this worker.
 189      An array of arg types is returned.  The length of the array is returned in
 190      NARGS.  The type of the 'this' object is returned as the first element of
 191      array.  */
 192
 193   type **get_arg_types (int *nargs);
 194
 195   /* Return the type of the result of the xmethod encapsulated in this worker.
 196      OBJECT, ARGS, NARGS are the same as for invoke.  */
 197
 198   type *get_result_type (value *object, value **args, int nargs);
 199
 200 private:
 201
 202   /* Return the types of the arguments the method takes.  The number of
 203      arguments is returned in NARGS, and their types are returned in the array
 204      ARGTYPES.  */
 205
 206   virtual enum ext_lang_rc do_get_arg_types
 207     (int *nargs, struct type ***arg_types) = 0;
 208
 209   /* Fetch the type of the result of the method implemented by this worker.
 210      OBJECT, ARGS, NARGS are the same as for the invoked method.  The result
 211      type is stored in *RESULT_TYPE.  */
 212
 213   virtual enum ext_lang_rc do_get_result_type
 214     (struct value *obj, struct value **args, int nargs,
 215      struct type **result_type_ptr) = 0;
 216
 217   /* The language the xmethod worker is implemented in.  */
 218
 219   const extension_language_defn *m_extlang;
 220 };
 221
 222 typedef std::unique_ptr<xmethod_worker> xmethod_worker_up;
 223
 224 /* The interface for gdb's own extension(/scripting) language.  */
 225 extern const struct extension_language_defn extension_language_gdb;
 226
 227 extern const struct extension_language_defn *get_ext_lang_defn
 228   (enum extension_language lang);
 229
 230 extern const struct extension_language_defn *get_ext_lang_of_file
 231   (const char *file);
 232
 233 extern int ext_lang_present_p (const struct extension_language_defn *);
 234
 235 extern int ext_lang_initialized_p (const struct extension_language_defn *);
 236
 237 extern void throw_ext_lang_unsupported
 238   (const struct extension_language_defn *);
 239
 240 /* Accessors for "public" attributes of the extension language definition.  */
 241
 242 extern enum extension_language ext_lang_kind
 243   (const struct extension_language_defn *);
 244
 245 extern const char *ext_lang_name (const struct extension_language_defn *);
 246
 247 extern const char *ext_lang_capitalized_name
 248   (const struct extension_language_defn *);
 249
 250 extern const char *ext_lang_suffix (const struct extension_language_defn *);
 251
 252 extern const char *ext_lang_auto_load_suffix
 253   (const struct extension_language_defn *);
 254
 255 extern script_sourcer_func *ext_lang_script_sourcer
 256   (const struct extension_language_defn *);
 257
 258 extern objfile_script_sourcer_func *ext_lang_objfile_script_sourcer
 259   (const struct extension_language_defn *);
 260
 261 extern objfile_script_executor_func *ext_lang_objfile_script_executor
 262   (const struct extension_language_defn *);
 263
 264 extern int ext_lang_auto_load_enabled (const struct extension_language_defn *);
 265
 266 /* Wrappers for each extension language API function that iterate over all
 267    extension languages.  */
 268
 269 extern void finish_ext_lang_initialization (void);
 270
 271 extern void eval_ext_lang_from_control_command (struct command_line *cmd);
 272
 273 extern void auto_load_ext_lang_scripts_for_objfile (struct objfile *);
 274
 275 extern struct ext_lang_type_printers *start_ext_lang_type_printers (void);
 276
 277 extern char *apply_ext_lang_type_printers (struct ext_lang_type_printers *,
 278                                            struct type *);
 279
 280 extern void free_ext_lang_type_printers (struct ext_lang_type_printers *);
 281
 282 extern int apply_ext_lang_val_pretty_printer
 283   (struct type *type,
 284    LONGEST embedded_offset, CORE_ADDR address,
 285    struct ui_file *stream, int recurse,
 286    struct value *val, const struct value_print_options *options,
 287    const struct language_defn *language);
 288
 289 extern enum ext_lang_bt_status apply_ext_lang_frame_filter
 290   (struct frame_info *frame, int flags, enum ext_lang_frame_args args_type,
 291    struct ui_out *out, int frame_low, int frame_high);
 292
 293 extern void preserve_ext_lang_values (struct objfile *, htab_t copied_types);
 294
 295 extern const struct extension_language_defn *get_breakpoint_cond_ext_lang
 296   (struct breakpoint *b, enum extension_language skip_lang);
 297
 298 extern int breakpoint_ext_lang_cond_says_stop (struct breakpoint *);
 299
 300 /* If a method with name METHOD_NAME is to be invoked on an object of type
 301    TYPE, then all extension languages are searched for implementations of
 302    methods with name METHOD_NAME.  All matches found are appended to the WORKERS
 303    vector.  */
 304
 305 extern void get_matching_xmethod_workers
 306   (struct type *type, const char *method_name,
 307    std::vector<xmethod_worker_up> *workers);
 308
 309 #endif /* EXTENSION_H */