gdb/extension-priv.h

   1 /* Private implementation details of interface between gdb and its
   2    extension languages.
   3
   4    Copyright (C) 2014-2022 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef EXTENSION_PRIV_H
  22 #define EXTENSION_PRIV_H
  23
  24 #include "extension.h"
  25 #include <signal.h>
  26 #include "cli/cli-script.h"
  27
  28 /* High level description of an extension/scripting language.
  29    An entry for each is compiled into GDB regardless of whether the support
  30    is present.  This is done so that we can issue meaningful errors if the
  31    support is not compiled in.  */
  32
  33 struct extension_language_defn
  34 {
  35   /* Enum of the extension language.  */
  36   enum extension_language language;
  37
  38   /* The name of the extension language, lowercase.  E.g., python.  */
  39   const char *name;
  40
  41   /* The capitalized name of the extension language.
  42      For python this is "Python".  For gdb this is "GDB".  */
  43   const char *capitalized_name;
  44
  45   /* The file suffix of this extension language.  E.g., ".py".  */
  46   const char *suffix;
  47
  48   /* The suffix of per-objfile scripts to auto-load.
  49      E.g., When the program loads libfoo.so, look for libfoo.so-gdb.py.  */
  50   const char *auto_load_suffix;
  51
  52   /* We support embedding external extension language code in GDB's own
  53      scripting language.  We do this by having a special command that begins
  54      the extension language snippet, and terminate it with "end".
  55      This specifies the control type used to implement this.  */
  56   enum command_control_type cli_control_type;
  57
  58   /* A pointer to the "methods" to load scripts in this language,
  59      or NULL if the support is not compiled into GDB.  */
  60   const struct extension_language_script_ops *script_ops;
  61
  62   /* Either a pointer to the "methods" of the extension language interface
  63      or NULL if the support is not compiled into GDB.
  64      This is also NULL for GDB's own scripting language which is relatively
  65      primitive, and doesn't provide these features.  */
  66   const struct extension_language_ops *ops;
  67 };
  68
  69 /* The interface for loading scripts from external extension languages,
  70    as well as GDB's own scripting language.
  71    All of these methods are required to be implemented.
  72
  73    By convention all of these functions take a pseudo-this parameter
  74    as the first argument.  */
  75
  76 struct extension_language_script_ops
  77 {
  78   /* Load a script.  This is called, e.g., via the "source" command.
  79      If there's an error while processing the script this function may,
  80      but is not required to, throw an error.  */
  81   script_sourcer_func *script_sourcer;
  82
  83   /* Load a script attached to an objfile.
  84      If there's an error while processing the script this function may,
  85      but is not required to, throw an error.  */
  86   objfile_script_sourcer_func *objfile_script_sourcer;
  87
  88   /* Execute a script attached to an objfile.
  89      If there's an error while processing the script this function may,
  90      but is not required to, throw an error.  */
  91   objfile_script_executor_func *objfile_script_executor;
  92
  93   /* Return non-zero if auto-loading scripts in this extension language
  94      is enabled.  */
  95   bool (*auto_load_enabled) (const struct extension_language_defn *);
  96 };
  97
  98 /* The interface for making calls from GDB to an external extension
  99    language.  This is for non-script-loading related functionality, like
 100    pretty-printing, etc.  The reason these are separated out is GDB's own
 101    scripting language makes use of extension_language_script_opts, but it
 102    makes no use of these.  There is no (current) intention to split
 103    extension_language_ops up any further.
 104    All of these methods are optional and may be NULL, except where
 105    otherwise indicated.
 106
 107    By convention all of these functions take a pseudo-this parameter
 108    as the first argument.  */
 109
 110 struct extension_language_ops
 111 {
 112   /* Called after GDB has processed the early initialization settings
 113      files.  This is when the extension language should be initialized.  By
 114      the time this is called all of the earlier initialization functions
 115      have already been called.  */
 116   void (*initialize) (const struct extension_language_defn *);
 117
 118   /* Return non-zero if the extension language successfully initialized.
 119      This method is required.  */
 120   int (*initialized) (const struct extension_language_defn *);
 121
 122   /* Process a sequence of commands embedded in GDB's own scripting language.
 123      E.g.,
 124      python
 125      print 42
 126      end  */
 127   void (*eval_from_control_command) (const struct extension_language_defn *,
 128                                      struct command_line *);
 129
 130   /* Type-printing support:
 131      start_type_printers, apply_type_printers, free_type_printers.
 132      These methods are optional and may be NULL, but if one of them is
 133      implemented then they all must be.  */
 134
 135   /* Called before printing a type.  */
 136   void (*start_type_printers) (const struct extension_language_defn *,
 137                                struct ext_lang_type_printers *);
 138
 139   /* Try to pretty-print TYPE.  If successful the pretty-printed type is
 140      stored in *PRETTIED_TYPE, and the caller must free it.
 141      Returns EXT_LANG_RC_OK upon success, EXT_LANG_RC_NOP if the type
 142      is not recognized, and EXT_LANG_RC_ERROR if an error was encountered.
 143      This function has a bit of a funny name, since it actually applies
 144      recognizers, but this seemed clearer given the start_type_printers
 145      and free_type_printers functions.  */
 146   enum ext_lang_rc (*apply_type_printers)
 147     (const struct extension_language_defn *,
 148      const struct ext_lang_type_printers *,
 149      struct type *, char **prettied_type);
 150
 151   /* Called after a type has been printed to give the type pretty-printer
 152      mechanism an opportunity to clean up.  */
 153   void (*free_type_printers) (const struct extension_language_defn *,
 154                               struct ext_lang_type_printers *);
 155
 156   /* Try to pretty-print a value, onto stdio stream STREAM according
 157      to OPTIONS.  VAL is the object to print.  Returns EXT_LANG_RC_OK
 158      upon success, EXT_LANG_RC_NOP if the value is not recognized, and
 159      EXT_LANG_RC_ERROR if an error was encountered.  */
 160   enum ext_lang_rc (*apply_val_pretty_printer)
 161     (const struct extension_language_defn *,
 162      struct value *val, struct ui_file *stream, int recurse,
 163      const struct value_print_options *options,
 164      const struct language_defn *language);
 165
 166   /* GDB access to the "frame filter" feature.
 167      FRAME is the source frame to start frame-filter invocation.  FLAGS is an
 168      integer holding the flags for printing.  The following elements of
 169      the FRAME_FILTER_FLAGS enum denotes the make-up of FLAGS:
 170      PRINT_LEVEL is a flag indicating whether to print the frame's
 171      relative level in the output.  PRINT_FRAME_INFO is a flag that
 172      indicates whether this function should print the frame
 173      information, PRINT_ARGS is a flag that indicates whether to print
 174      frame arguments, and PRINT_LOCALS, likewise, with frame local
 175      variables.  ARGS_TYPE is an enumerator describing the argument
 176      format, OUT is the output stream to print.  FRAME_LOW is the
 177      beginning of the slice of frames to print, and FRAME_HIGH is the
 178      upper limit of the frames to count.  Returns SCR_BT_ERROR on error,
 179      or SCR_BT_COMPLETED on success.  */
 180   enum ext_lang_bt_status (*apply_frame_filter)
 181     (const struct extension_language_defn *,
 182      struct frame_info *frame, frame_filter_flags flags,
 183      enum ext_lang_frame_args args_type,
 184      struct ui_out *out, int frame_low, int frame_high);
 185
 186   /* Update values held by the extension language when OBJFILE is discarded.
 187      New global types must be created for every such value, which must then be
 188      updated to use the new types.
 189      This function typically just iterates over all appropriate values and
 190      calls preserve_one_value for each one.
 191      COPIED_TYPES is used to prevent cycles / duplicates and is passed to
 192      preserve_one_value.  */
 193   void (*preserve_values) (const struct extension_language_defn *,
 194                            struct objfile *objfile, htab_t copied_types);
 195
 196   /* Return non-zero if there is a stop condition for the breakpoint.
 197      This is used to implement the restriction that a breakpoint may have
 198      at most one condition.  */
 199   int (*breakpoint_has_cond) (const struct extension_language_defn *,
 200                               struct breakpoint *);
 201
 202   /* Return a value of enum ext_lang_bp_stop indicating if there is a stop
 203      condition for the breakpoint, and if so whether the program should
 204      stop.  This is called when the program has stopped at the specified
 205      breakpoint.
 206      While breakpoints can have at most one condition, this is called for
 207      every extension language, even if another extension language has a
 208      "stop" method: other kinds of breakpoints may be implemented using
 209      this method, e.g., "finish breakpoints" in Python.  */
 210   enum ext_lang_bp_stop (*breakpoint_cond_says_stop)
 211     (const struct extension_language_defn *, struct breakpoint *);
 212
 213   /* The next two are used to connect GDB's SIGINT handling with the
 214      extension language's.
 215
 216      Terminology: If an extension language can use GDB's SIGINT handling then
 217      we say the extension language has "cooperative SIGINT handling".
 218      Python is an example of this.
 219
 220      These need not be implemented, but if one of them is implemented
 221      then they all must be.  */
 222
 223   /* Set the SIGINT indicator.
 224      This is called by GDB's SIGINT handler and must be async-safe.  */
 225   void (*set_quit_flag) (const struct extension_language_defn *);
 226
 227   /* Return non-zero if a SIGINT has occurred.
 228      This is expected to also clear the indicator.  */
 229   int (*check_quit_flag) (const struct extension_language_defn *);
 230
 231   /* Called before gdb prints its prompt, giving extension languages an
 232      opportunity to change it with set_prompt.
 233      Returns EXT_LANG_RC_OK if the prompt was changed, EXT_LANG_RC_NOP if
 234      the prompt was not changed, and EXT_LANG_RC_ERROR if an error was
 235      encountered.
 236      Extension languages are called in order, and once the prompt is
 237      changed or an error occurs no further languages are called.  */
 238   enum ext_lang_rc (*before_prompt) (const struct extension_language_defn *,
 239                                      const char *current_gdb_prompt);
 240
 241   /* Return a vector of matching xmethod workers defined in this
 242      extension language.  The workers service methods with name
 243      METHOD_NAME on objects of type OBJ_TYPE.  The vector is returned
 244      in DM_VEC.
 245
 246      This field may be NULL if the extension language does not support
 247      xmethods.  */
 248   enum ext_lang_rc (*get_matching_xmethod_workers)
 249     (const struct extension_language_defn *extlang,
 250      struct type *obj_type,
 251      const char *method_name,
 252      std::vector<xmethod_worker_up> *dm_vec);
 253
 254   /* Colorize a source file.  NAME is the source file's name, and
 255      CONTENTS is the contents of the file.  This should either return
 256      colorized (using ANSI terminal escapes) version of the contents,
 257      or an empty option.  */
 258   gdb::optional<std::string> (*colorize) (const std::string &name,
 259                                           const std::string &contents);
 260
 261   /* Colorize a single line of disassembler output, CONTENT.  This should
 262      either return colorized (using ANSI terminal escapes) version of the
 263      contents, or an empty optional.  */
 264   gdb::optional<std::string> (*colorize_disasm) (const std::string &content,
 265                                                  gdbarch *gdbarch);
 266 };
 267
 268 /* State necessary to restore a signal handler to its previous value.  */
 269
 270 struct signal_handler
 271 {
 272   /* Non-zero if "handler" has been set.  */
 273   int handler_saved;
 274
 275   /* The signal handler.  */
 276   sighandler_t handler;
 277 };
 278
 279 /* State necessary to restore the currently active extension language
 280    to its previous value.  */
 281
 282 struct active_ext_lang_state
 283 {
 284   /* The previously active extension language.  */
 285   const struct extension_language_defn *ext_lang;
 286
 287   /* Its SIGINT handler.  */
 288   struct signal_handler sigint_handler;
 289 };
 290
 291 extern const struct extension_language_defn *get_active_ext_lang (void);
 292
 293 extern struct active_ext_lang_state *set_active_ext_lang
 294   (const struct extension_language_defn *);
 295
 296 extern void restore_active_ext_lang (struct active_ext_lang_state *previous);
 297
 298 #endif /* EXTENSION_PRIV_H */