gdb/extension.h

   1 /* Interface between gdb and its extension languages.
   2
   3    Copyright (C) 2014-2019 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 "gdbsupport/vec.h"
  25 #include "gdbsupport/array-view.h"
  26
  27 struct breakpoint;
  28 struct command_line;
  29 struct frame_info;
  30 struct language_defn;
  31 struct objfile;
  32 struct extension_language_defn;
  33 struct type;
  34 struct ui_file;
  35 struct ui_out;
  36 struct value;
  37 struct value_print_options;
  38
  39 /* A function to load and process a script file.
  40    The file has been opened and is ready to be read from the beginning.
  41    Any exceptions are not caught, and are passed to the caller.  */
  42 typedef void script_sourcer_func (const struct extension_language_defn *,
  43                                   FILE *stream, const char *filename);
  44
  45 /* A function to load and process a script for an objfile.
  46    The file has been opened and is ready to be read from the beginning.
  47    Any exceptions are not caught, and are passed to the caller.  */
  48 typedef void objfile_script_sourcer_func
  49   (const struct extension_language_defn *,
  50    struct objfile *, FILE *stream, const char *filename);
  51
  52 /* A function to execute a script for an objfile.
  53    Any exceptions are not caught, and are passed to the caller.  */
  54 typedef void objfile_script_executor_func
  55   (const struct extension_language_defn *,
  56    struct objfile *, const char *name, const char *script);
  57
  58 /* Enum of each extension(/scripting) language.  */
  59
  60 enum extension_language
  61   {
  62     EXT_LANG_NONE,
  63     EXT_LANG_GDB,
  64     EXT_LANG_PYTHON,
  65     EXT_LANG_GUILE
  66   };
  67
  68 /* Extension language frame-filter status return values.  */
  69
  70 enum ext_lang_bt_status
  71   {
  72     /* Return when an error has occurred in processing frame filters,
  73        or when printing the stack.  */
  74     EXT_LANG_BT_ERROR = -1,
  75
  76     /* Return from internal routines to indicate that the function
  77        succeeded.  */
  78     EXT_LANG_BT_OK = 1,
  79
  80     /* Return when the frame filter process is complete, but there
  81        were no filter registered and enabled to process.  */
  82     EXT_LANG_BT_NO_FILTERS = 2
  83   };
  84
  85 /* Flags to pass to apply_extlang_frame_filter.  */
  86
  87 enum frame_filter_flag
  88   {
  89     /* Set this flag if frame level is to be printed.  */
  90     PRINT_LEVEL = 1 << 0,
  91
  92     /* Set this flag if frame information is to be printed.  */
  93     PRINT_FRAME_INFO = 1 << 1,
  94
  95     /* Set this flag if frame arguments are to be printed.  */
  96     PRINT_ARGS = 1 << 2,
  97
  98     /* Set this flag if frame locals are to be printed.  */
  99     PRINT_LOCALS = 1 << 3,
 100
 101     /* Set this flag if a "More frames" message is to be printed.  */
 102     PRINT_MORE_FRAMES = 1 << 4,
 103
 104     /* Set this flag if elided frames should not be printed.  */
 105     PRINT_HIDE = 1 << 5,
 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   ext_lang_type_printers ();
 151   ~ext_lang_type_printers ();
 152
 153   DISABLE_COPY_AND_ASSIGN (ext_lang_type_printers);
 154
 155   /* Type-printers from Python.  */
 156   void *py_type_printers = nullptr;
 157 };
 158
 159 /* The return code for some API calls.  */
 160
 161 enum ext_lang_rc
 162 {
 163   /* The operation completed successfully.  */
 164   EXT_LANG_RC_OK,
 165
 166   /* The operation was not performed (e.g., no pretty-printer).  */
 167   EXT_LANG_RC_NOP,
 168
 169   /* There was an error (e.g., Python error while printing a value).
 170      When an error occurs no further extension languages are tried.
 171      This is to preserve existing behaviour, and because it's convenient
 172      for Python developers.
 173      Note: This is different than encountering a memory error trying to read
 174      a value for pretty-printing.  Here we're referring to, e.g., programming
 175      errors that trigger an exception in the extension language.  */
 176   EXT_LANG_RC_ERROR
 177 };
 178
 179 /* A type which holds its extension language specific xmethod worker data.  */
 180
 181 struct xmethod_worker
 182 {
 183   xmethod_worker (const extension_language_defn *extlang)
 184   : m_extlang (extlang)
 185   {}
 186
 187   virtual ~xmethod_worker () = default;
 188
 189   /* Invoke the xmethod encapsulated in this worker and return the result.
 190      The method is invoked on OBJ with arguments in the ARGS array.  */
 191
 192   virtual value *invoke (value *obj, gdb::array_view<value *> args) = 0;
 193
 194   /* Return the arg types of the xmethod encapsulated in this worker.
 195      The type of the 'this' object is returned as the first element of
 196      the vector.  */
 197
 198   std::vector<type *> get_arg_types ();
 199
 200   /* Return the type of the result of the xmethod encapsulated in this worker.
 201      OBJECT and ARGS are the same as for invoke.  */
 202
 203   type *get_result_type (value *object, gdb::array_view<value *> args);
 204
 205 private:
 206
 207   /* Return the types of the arguments the method takes.  The types
 208      are returned in TYPE_ARGS, one per argument.  */
 209
 210   virtual enum ext_lang_rc do_get_arg_types
 211     (std::vector<type *> *type_args) = 0;
 212
 213   /* Fetch the type of the result of the method implemented by this
 214      worker.  OBJECT and ARGS are the same as for the invoked method.
 215      The result type is stored in *RESULT_TYPE.  */
 216
 217   virtual enum ext_lang_rc do_get_result_type
 218     (struct value *obj, gdb::array_view<value *> args,
 219      struct type **result_type_ptr) = 0;
 220
 221   /* The language the xmethod worker is implemented in.  */
 222
 223   const extension_language_defn *m_extlang;
 224 };
 225
 226 typedef std::unique_ptr<xmethod_worker> xmethod_worker_up;
 227
 228 /* The interface for gdb's own extension(/scripting) language.  */
 229 extern const struct extension_language_defn extension_language_gdb;
 230
 231 extern const struct extension_language_defn *get_ext_lang_defn
 232   (enum extension_language lang);
 233
 234 extern const struct extension_language_defn *get_ext_lang_of_file
 235   (const char *file);
 236
 237 extern int ext_lang_present_p (const struct extension_language_defn *);
 238
 239 extern int ext_lang_initialized_p (const struct extension_language_defn *);
 240
 241 extern void throw_ext_lang_unsupported
 242   (const struct extension_language_defn *);
 243
 244 /* Accessors for "public" attributes of the extension language definition.  */
 245
 246 extern enum extension_language ext_lang_kind
 247   (const struct extension_language_defn *);
 248
 249 extern const char *ext_lang_name (const struct extension_language_defn *);
 250
 251 extern const char *ext_lang_capitalized_name
 252   (const struct extension_language_defn *);
 253
 254 extern const char *ext_lang_suffix (const struct extension_language_defn *);
 255
 256 extern const char *ext_lang_auto_load_suffix
 257   (const struct extension_language_defn *);
 258
 259 extern script_sourcer_func *ext_lang_script_sourcer
 260   (const struct extension_language_defn *);
 261
 262 extern objfile_script_sourcer_func *ext_lang_objfile_script_sourcer
 263   (const struct extension_language_defn *);
 264
 265 extern objfile_script_executor_func *ext_lang_objfile_script_executor
 266   (const struct extension_language_defn *);
 267
 268 extern int ext_lang_auto_load_enabled (const struct extension_language_defn *);
 269
 270 /* Wrappers for each extension language API function that iterate over all
 271    extension languages.  */
 272
 273 extern void finish_ext_lang_initialization (void);
 274
 275 extern void eval_ext_lang_from_control_command (struct command_line *cmd);
 276
 277 extern void auto_load_ext_lang_scripts_for_objfile (struct objfile *);
 278
 279 extern char *apply_ext_lang_type_printers (struct ext_lang_type_printers *,
 280                                            struct type *);
 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, frame_filter_flags flags,
 291    enum ext_lang_frame_args args_type,
 292    struct ui_out *out, int frame_low, int frame_high);
 293
 294 extern void preserve_ext_lang_values (struct objfile *, htab_t copied_types);
 295
 296 extern const struct extension_language_defn *get_breakpoint_cond_ext_lang
 297   (struct breakpoint *b, enum extension_language skip_lang);
 298
 299 extern int breakpoint_ext_lang_cond_says_stop (struct breakpoint *);
 300
 301 /* If a method with name METHOD_NAME is to be invoked on an object of type
 302    TYPE, then all extension languages are searched for implementations of
 303    methods with name METHOD_NAME.  All matches found are appended to the WORKERS
 304    vector.  */
 305
 306 extern void get_matching_xmethod_workers
 307   (struct type *type, const char *method_name,
 308    std::vector<xmethod_worker_up> *workers);
 309
 310 #endif /* EXTENSION_H */