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, but there
  80        were no filter registered and enabled to process.  */
  81     EXT_LANG_BT_NO_FILTERS = 2
  82   };
  83
  84 /* Flags to pass to apply_extlang_frame_filter.  */
  85
  86 enum frame_filter_flag
  87   {
  88     /* Set this flag if frame level is to be printed.  */
  89     PRINT_LEVEL = 1 << 0,
  90
  91     /* Set this flag if frame information is to be printed.  */
  92     PRINT_FRAME_INFO = 1 << 1,
  93
  94     /* Set this flag if frame arguments are to be printed.  */
  95     PRINT_ARGS = 1 << 2,
  96
  97     /* Set this flag if frame locals are to be printed.  */
  98     PRINT_LOCALS = 1 << 3,
  99
 100     /* Set this flag if a "More frames" message is to be printed.  */
 101     PRINT_MORE_FRAMES = 1 << 4,
 102
 103     /* Set this flag if elided frames should not be printed.  */
 104     PRINT_HIDE = 1 << 5,
 105   };
 106
 107 DEF_ENUM_FLAGS_TYPE (enum frame_filter_flag, frame_filter_flags);
 108
 109 /* A choice of the different frame argument printing strategies that
 110    can occur in different cases of frame filter instantiation.  */
 111
 112 enum ext_lang_frame_args
 113   {
 114     /* Print no values for arguments when invoked from the MI. */
 115     NO_VALUES = PRINT_NO_VALUES,
 116
 117     MI_PRINT_ALL_VALUES = PRINT_ALL_VALUES,
 118
 119     /* Print only simple values (what MI defines as "simple") for
 120        arguments when invoked from the MI. */
 121     MI_PRINT_SIMPLE_VALUES = PRINT_SIMPLE_VALUES,
 122
 123     /* Print only scalar values for arguments when invoked from the CLI. */
 124     CLI_SCALAR_VALUES,
 125
 126     /* Print all values for arguments when invoked from the CLI. */
 127     CLI_ALL_VALUES
 128   };
 129
 130 /* The possible results of
 131    extension_language_ops.breakpoint_cond_says_stop.  */
 132
 133 enum ext_lang_bp_stop
 134   {
 135     /* No "stop" condition is set.  */
 136     EXT_LANG_BP_STOP_UNSET,
 137
 138     /* A "stop" condition is set, and it says "don't stop".  */
 139     EXT_LANG_BP_STOP_NO,
 140
 141     /* A "stop" condition is set, and it says "stop".  */
 142     EXT_LANG_BP_STOP_YES
 143   };
 144
 145 /* Table of type printers associated with the global typedef table.  */
 146
 147 struct ext_lang_type_printers
 148 {
 149   /* Type-printers from Python.  */
 150   void *py_type_printers;
 151 };
 152
 153 /* The return code for some API calls.  */
 154
 155 enum ext_lang_rc
 156 {
 157   /* The operation completed successfully.  */
 158   EXT_LANG_RC_OK,
 159
 160   /* The operation was not performed (e.g., no pretty-printer).  */
 161   EXT_LANG_RC_NOP,
 162
 163   /* There was an error (e.g., Python error while printing a value).
 164      When an error occurs no further extension languages are tried.
 165      This is to preserve existing behaviour, and because it's convenient
 166      for Python developers.
 167      Note: This is different than encountering a memory error trying to read
 168      a value for pretty-printing.  Here we're referring to, e.g., programming
 169      errors that trigger an exception in the extension language.  */
 170   EXT_LANG_RC_ERROR
 171 };
 172
 173 /* A type which holds its extension language specific xmethod worker data.  */
 174
 175 struct xmethod_worker
 176 {
 177   xmethod_worker (const extension_language_defn *extlang)
 178   : m_extlang (extlang)
 179   {}
 180
 181   virtual ~xmethod_worker () = default;
 182
 183   /* Invoke the xmethod encapsulated in this worker and return the result.
 184      The method is invoked on OBJ with arguments in the ARGS array.  NARGS is
 185      the length of the this array.  */
 186
 187   virtual value *invoke (value *obj, value **args, int nargs) = 0;
 188
 189   /* Return the arg types of the xmethod encapsulated in this worker.
 190      An array of arg types is returned.  The length of the array is returned in
 191      NARGS.  The type of the 'this' object is returned as the first element of
 192      array.  */
 193
 194   type **get_arg_types (int *nargs);
 195
 196   /* Return the type of the result of the xmethod encapsulated in this worker.
 197      OBJECT, ARGS, NARGS are the same as for invoke.  */
 198
 199   type *get_result_type (value *object, value **args, int nargs);
 200
 201 private:
 202
 203   /* Return the types of the arguments the method takes.  The number of
 204      arguments is returned in NARGS, and their types are returned in the array
 205      ARGTYPES.  */
 206
 207   virtual enum ext_lang_rc do_get_arg_types
 208     (int *nargs, struct type ***arg_types) = 0;
 209
 210   /* Fetch the type of the result of the method implemented by this worker.
 211      OBJECT, ARGS, NARGS are the same as for the invoked method.  The result
 212      type is stored in *RESULT_TYPE.  */
 213
 214   virtual enum ext_lang_rc do_get_result_type
 215     (struct value *obj, struct value **args, int nargs,
 216      struct type **result_type_ptr) = 0;
 217
 218   /* The language the xmethod worker is implemented in.  */
 219
 220   const extension_language_defn *m_extlang;
 221 };
 222
 223 typedef std::unique_ptr<xmethod_worker> xmethod_worker_up;
 224
 225 /* The interface for gdb's own extension(/scripting) language.  */
 226 extern const struct extension_language_defn extension_language_gdb;
 227
 228 extern const struct extension_language_defn *get_ext_lang_defn
 229   (enum extension_language lang);
 230
 231 extern const struct extension_language_defn *get_ext_lang_of_file
 232   (const char *file);
 233
 234 extern int ext_lang_present_p (const struct extension_language_defn *);
 235
 236 extern int ext_lang_initialized_p (const struct extension_language_defn *);
 237
 238 extern void throw_ext_lang_unsupported
 239   (const struct extension_language_defn *);
 240
 241 /* Accessors for "public" attributes of the extension language definition.  */
 242
 243 extern enum extension_language ext_lang_kind
 244   (const struct extension_language_defn *);
 245
 246 extern const char *ext_lang_name (const struct extension_language_defn *);
 247
 248 extern const char *ext_lang_capitalized_name
 249   (const struct extension_language_defn *);
 250
 251 extern const char *ext_lang_suffix (const struct extension_language_defn *);
 252
 253 extern const char *ext_lang_auto_load_suffix
 254   (const struct extension_language_defn *);
 255
 256 extern script_sourcer_func *ext_lang_script_sourcer
 257   (const struct extension_language_defn *);
 258
 259 extern objfile_script_sourcer_func *ext_lang_objfile_script_sourcer
 260   (const struct extension_language_defn *);
 261
 262 extern objfile_script_executor_func *ext_lang_objfile_script_executor
 263   (const struct extension_language_defn *);
 264
 265 extern int ext_lang_auto_load_enabled (const struct extension_language_defn *);
 266
 267 /* Wrappers for each extension language API function that iterate over all
 268    extension languages.  */
 269
 270 extern void finish_ext_lang_initialization (void);
 271
 272 extern void eval_ext_lang_from_control_command (struct command_line *cmd);
 273
 274 extern void auto_load_ext_lang_scripts_for_objfile (struct objfile *);
 275
 276 extern struct ext_lang_type_printers *start_ext_lang_type_printers (void);
 277
 278 extern char *apply_ext_lang_type_printers (struct ext_lang_type_printers *,
 279                                            struct type *);
 280
 281 extern void free_ext_lang_type_printers (struct ext_lang_type_printers *);
 282
 283 extern int apply_ext_lang_val_pretty_printer
 284   (struct type *type,
 285    LONGEST embedded_offset, CORE_ADDR address,
 286    struct ui_file *stream, int recurse,
 287    struct value *val, const struct value_print_options *options,
 288    const struct language_defn *language);
 289
 290 extern enum ext_lang_bt_status apply_ext_lang_frame_filter
 291   (struct frame_info *frame, frame_filter_flags flags,
 292    enum ext_lang_frame_args args_type,
 293    struct ui_out *out, int frame_low, int frame_high);
 294
 295 extern void preserve_ext_lang_values (struct objfile *, htab_t copied_types);
 296
 297 extern const struct extension_language_defn *get_breakpoint_cond_ext_lang
 298   (struct breakpoint *b, enum extension_language skip_lang);
 299
 300 extern int breakpoint_ext_lang_cond_says_stop (struct breakpoint *);
 301
 302 /* If a method with name METHOD_NAME is to be invoked on an object of type
 303    TYPE, then all extension languages are searched for implementations of
 304    methods with name METHOD_NAME.  All matches found are appended to the WORKERS
 305    vector.  */
 306
 307 extern void get_matching_xmethod_workers
 308   (struct type *type, const char *method_name,
 309    std::vector<xmethod_worker_up> *workers);
 310
 311 #endif /* EXTENSION_H */