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_flag
  91   {
  92     /* Set this flag if frame level is to be printed.  */
  93     PRINT_LEVEL = 1 << 0,
  94
  95     /* Set this flag if frame information is to be printed.  */
  96     PRINT_FRAME_INFO = 1 << 1,
  97
  98     /* Set this flag if frame arguments are to be printed.  */
  99     PRINT_ARGS = 1 << 2,
 100
 101     /* Set this flag if frame locals are to be printed.  */
 102     PRINT_LOCALS = 1 << 3,
 103
 104     /* Set this flag if a "More frames" message is to be printed.  */
 105     PRINT_MORE_FRAMES = 1 << 4,
 106
 107     /* Set this flag if elided frames should not be printed.  */
 108     PRINT_HIDE = 1 << 5,
 109   };
 110
 111 DEF_ENUM_FLAGS_TYPE (enum frame_filter_flag, frame_filter_flags);
 112
 113 /* A choice of the different frame argument printing strategies that
 114    can occur in different cases of frame filter instantiation.  */
 115
 116 enum ext_lang_frame_args
 117   {
 118     /* Print no values for arguments when invoked from the MI. */
 119     NO_VALUES = PRINT_NO_VALUES,
 120
 121     MI_PRINT_ALL_VALUES = PRINT_ALL_VALUES,
 122
 123     /* Print only simple values (what MI defines as "simple") for
 124        arguments when invoked from the MI. */
 125     MI_PRINT_SIMPLE_VALUES = PRINT_SIMPLE_VALUES,
 126
 127     /* Print only scalar values for arguments when invoked from the CLI. */
 128     CLI_SCALAR_VALUES,
 129
 130     /* Print all values for arguments when invoked from the CLI. */
 131     CLI_ALL_VALUES
 132   };
 133
 134 /* The possible results of
 135    extension_language_ops.breakpoint_cond_says_stop.  */
 136
 137 enum ext_lang_bp_stop
 138   {
 139     /* No "stop" condition is set.  */
 140     EXT_LANG_BP_STOP_UNSET,
 141
 142     /* A "stop" condition is set, and it says "don't stop".  */
 143     EXT_LANG_BP_STOP_NO,
 144
 145     /* A "stop" condition is set, and it says "stop".  */
 146     EXT_LANG_BP_STOP_YES
 147   };
 148
 149 /* Table of type printers associated with the global typedef table.  */
 150
 151 struct ext_lang_type_printers
 152 {
 153   /* Type-printers from Python.  */
 154   void *py_type_printers;
 155 };
 156
 157 /* The return code for some API calls.  */
 158
 159 enum ext_lang_rc
 160 {
 161   /* The operation completed successfully.  */
 162   EXT_LANG_RC_OK,
 163
 164   /* The operation was not performed (e.g., no pretty-printer).  */
 165   EXT_LANG_RC_NOP,
 166
 167   /* There was an error (e.g., Python error while printing a value).
 168      When an error occurs no further extension languages are tried.
 169      This is to preserve existing behaviour, and because it's convenient
 170      for Python developers.
 171      Note: This is different than encountering a memory error trying to read
 172      a value for pretty-printing.  Here we're referring to, e.g., programming
 173      errors that trigger an exception in the extension language.  */
 174   EXT_LANG_RC_ERROR
 175 };
 176
 177 /* A type which holds its extension language specific xmethod worker data.  */
 178
 179 struct xmethod_worker
 180 {
 181   xmethod_worker (const extension_language_defn *extlang)
 182   : m_extlang (extlang)
 183   {}
 184
 185   virtual ~xmethod_worker () = default;
 186
 187   /* Invoke the xmethod encapsulated in this worker and return the result.
 188      The method is invoked on OBJ with arguments in the ARGS array.  NARGS is
 189      the length of the this array.  */
 190
 191   virtual value *invoke (value *obj, value **args, int nargs) = 0;
 192
 193   /* Return the arg types of the xmethod encapsulated in this worker.
 194      An array of arg types is returned.  The length of the array is returned in
 195      NARGS.  The type of the 'this' object is returned as the first element of
 196      array.  */
 197
 198   type **get_arg_types (int *nargs);
 199
 200   /* Return the type of the result of the xmethod encapsulated in this worker.
 201      OBJECT, ARGS, NARGS are the same as for invoke.  */
 202
 203   type *get_result_type (value *object, value **args, int nargs);
 204
 205 private:
 206
 207   /* Return the types of the arguments the method takes.  The number of
 208      arguments is returned in NARGS, and their types are returned in the array
 209      ARGTYPES.  */
 210
 211   virtual enum ext_lang_rc do_get_arg_types
 212     (int *nargs, struct type ***arg_types) = 0;
 213
 214   /* Fetch the type of the result of the method implemented by this worker.
 215      OBJECT, ARGS, NARGS are the same as for the invoked method.  The result
 216      type is stored in *RESULT_TYPE.  */
 217
 218   virtual enum ext_lang_rc do_get_result_type
 219     (struct value *obj, struct value **args, int nargs,
 220      struct type **result_type_ptr) = 0;
 221
 222   /* The language the xmethod worker is implemented in.  */
 223
 224   const extension_language_defn *m_extlang;
 225 };
 226
 227 typedef std::unique_ptr<xmethod_worker> xmethod_worker_up;
 228
 229 /* The interface for gdb's own extension(/scripting) language.  */
 230 extern const struct extension_language_defn extension_language_gdb;
 231
 232 extern const struct extension_language_defn *get_ext_lang_defn
 233   (enum extension_language lang);
 234
 235 extern const struct extension_language_defn *get_ext_lang_of_file
 236   (const char *file);
 237
 238 extern int ext_lang_present_p (const struct extension_language_defn *);
 239
 240 extern int ext_lang_initialized_p (const struct extension_language_defn *);
 241
 242 extern void throw_ext_lang_unsupported
 243   (const struct extension_language_defn *);
 244
 245 /* Accessors for "public" attributes of the extension language definition.  */
 246
 247 extern enum extension_language ext_lang_kind
 248   (const struct extension_language_defn *);
 249
 250 extern const char *ext_lang_name (const struct extension_language_defn *);
 251
 252 extern const char *ext_lang_capitalized_name
 253   (const struct extension_language_defn *);
 254
 255 extern const char *ext_lang_suffix (const struct extension_language_defn *);
 256
 257 extern const char *ext_lang_auto_load_suffix
 258   (const struct extension_language_defn *);
 259
 260 extern script_sourcer_func *ext_lang_script_sourcer
 261   (const struct extension_language_defn *);
 262
 263 extern objfile_script_sourcer_func *ext_lang_objfile_script_sourcer
 264   (const struct extension_language_defn *);
 265
 266 extern objfile_script_executor_func *ext_lang_objfile_script_executor
 267   (const struct extension_language_defn *);
 268
 269 extern int ext_lang_auto_load_enabled (const struct extension_language_defn *);
 270
 271 /* Wrappers for each extension language API function that iterate over all
 272    extension languages.  */
 273
 274 extern void finish_ext_lang_initialization (void);
 275
 276 extern void eval_ext_lang_from_control_command (struct command_line *cmd);
 277
 278 extern void auto_load_ext_lang_scripts_for_objfile (struct objfile *);
 279
 280 extern struct ext_lang_type_printers *start_ext_lang_type_printers (void);
 281
 282 extern char *apply_ext_lang_type_printers (struct ext_lang_type_printers *,
 283                                            struct type *);
 284
 285 extern void free_ext_lang_type_printers (struct ext_lang_type_printers *);
 286
 287 extern int apply_ext_lang_val_pretty_printer
 288   (struct type *type,
 289    LONGEST embedded_offset, CORE_ADDR address,
 290    struct ui_file *stream, int recurse,
 291    struct value *val, const struct value_print_options *options,
 292    const struct language_defn *language);
 293
 294 extern enum ext_lang_bt_status apply_ext_lang_frame_filter
 295   (struct frame_info *frame, frame_filter_flags flags,
 296    enum ext_lang_frame_args args_type,
 297    struct ui_out *out, int frame_low, int frame_high);
 298
 299 extern void preserve_ext_lang_values (struct objfile *, htab_t copied_types);
 300
 301 extern const struct extension_language_defn *get_breakpoint_cond_ext_lang
 302   (struct breakpoint *b, enum extension_language skip_lang);
 303
 304 extern int breakpoint_ext_lang_cond_says_stop (struct breakpoint *);
 305
 306 /* If a method with name METHOD_NAME is to be invoked on an object of type
 307    TYPE, then all extension languages are searched for implementations of
 308    methods with name METHOD_NAME.  All matches found are appended to the WORKERS
 309    vector.  */
 310
 311 extern void get_matching_xmethod_workers
 312   (struct type *type, const char *method_name,
 313    std::vector<xmethod_worker_up> *workers);
 314
 315 #endif /* EXTENSION_H */