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