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   /* Return the arg types of the xmethod encapsulated in this worker.
 186      An array of arg types is returned.  The length of the array is returned in
 187      NARGS.  The type of the 'this' object is returned as the first element of
 188      array.  */
 189
 190   type **get_arg_types (int *nargs);
 191
 192   /* Return the type of the result of the xmethod encapsulated in this worker.
 193      OBJECT, ARGS, NARGS are the same as for invoke.  */
 194
 195   type *get_result_type (value *object, value **args, int nargs);
 196
 197 private:
 198
 199   /* Return the types of the arguments the method takes.  The number of
 200      arguments is returned in NARGS, and their types are returned in the array
 201      ARGTYPES.  */
 202
 203   virtual enum ext_lang_rc do_get_arg_types
 204     (int *nargs, struct type ***arg_types) = 0;
 205
 206   /* Fetch the type of the result of the method implemented by this worker.
 207      OBJECT, ARGS, NARGS are the same as for the invoked method.  The result
 208      type is stored in *RESULT_TYPE.  */
 209
 210   virtual enum ext_lang_rc do_get_result_type
 211     (struct value *obj, struct value **args, int nargs,
 212      struct type **result_type_ptr) = 0;
 213
 214   /* The language the xmethod worker is implemented in.  */
 215
 216   const extension_language_defn *m_extlang;
 217 };
 218
 219 typedef std::unique_ptr<xmethod_worker> xmethod_worker_up;
 220
 221 /* The interface for gdb's own extension(/scripting) language.  */
 222 extern const struct extension_language_defn extension_language_gdb;
 223
 224 extern const struct extension_language_defn *get_ext_lang_defn
 225   (enum extension_language lang);
 226
 227 extern const struct extension_language_defn *get_ext_lang_of_file
 228   (const char *file);
 229
 230 extern int ext_lang_present_p (const struct extension_language_defn *);
 231
 232 extern int ext_lang_initialized_p (const struct extension_language_defn *);
 233
 234 extern void throw_ext_lang_unsupported
 235   (const struct extension_language_defn *);
 236
 237 /* Accessors for "public" attributes of the extension language definition.  */
 238
 239 extern enum extension_language ext_lang_kind
 240   (const struct extension_language_defn *);
 241
 242 extern const char *ext_lang_name (const struct extension_language_defn *);
 243
 244 extern const char *ext_lang_capitalized_name
 245   (const struct extension_language_defn *);
 246
 247 extern const char *ext_lang_suffix (const struct extension_language_defn *);
 248
 249 extern const char *ext_lang_auto_load_suffix
 250   (const struct extension_language_defn *);
 251
 252 extern script_sourcer_func *ext_lang_script_sourcer
 253   (const struct extension_language_defn *);
 254
 255 extern objfile_script_sourcer_func *ext_lang_objfile_script_sourcer
 256   (const struct extension_language_defn *);
 257
 258 extern objfile_script_executor_func *ext_lang_objfile_script_executor
 259   (const struct extension_language_defn *);
 260
 261 extern int ext_lang_auto_load_enabled (const struct extension_language_defn *);
 262
 263 /* Wrappers for each extension language API function that iterate over all
 264    extension languages.  */
 265
 266 extern void finish_ext_lang_initialization (void);
 267
 268 extern void eval_ext_lang_from_control_command (struct command_line *cmd);
 269
 270 extern void auto_load_ext_lang_scripts_for_objfile (struct objfile *);
 271
 272 extern struct ext_lang_type_printers *start_ext_lang_type_printers (void);
 273
 274 extern char *apply_ext_lang_type_printers (struct ext_lang_type_printers *,
 275                                            struct type *);
 276
 277 extern void free_ext_lang_type_printers (struct ext_lang_type_printers *);
 278
 279 extern int apply_ext_lang_val_pretty_printer
 280   (struct type *type,
 281    LONGEST embedded_offset, CORE_ADDR address,
 282    struct ui_file *stream, int recurse,
 283    struct value *val, const struct value_print_options *options,
 284    const struct language_defn *language);
 285
 286 extern enum ext_lang_bt_status apply_ext_lang_frame_filter
 287   (struct frame_info *frame, int flags, enum ext_lang_frame_args args_type,
 288    struct ui_out *out, int frame_low, int frame_high);
 289
 290 extern void preserve_ext_lang_values (struct objfile *, htab_t copied_types);
 291
 292 extern const struct extension_language_defn *get_breakpoint_cond_ext_lang
 293   (struct breakpoint *b, enum extension_language skip_lang);
 294
 295 extern int breakpoint_ext_lang_cond_says_stop (struct breakpoint *);
 296
 297 /* If a method with name METHOD_NAME is to be invoked on an object of type
 298    TYPE, then all extension languages are searched for implementations of
 299    methods with name METHOD_NAME.  All matches found are appended to the WORKERS
 300    vector.  */
 301
 302 extern void get_matching_xmethod_workers
 303   (struct type *type, const char *method_name,
 304    std::vector<xmethod_worker_up> *workers);
 305
 306 #endif /* EXTENSION_H */