gdb/common/common-exceptions.h - gdb

Data types defined

Macros defined

Source code

  1. /* Exception (throw catch) mechanism, for GDB, the GNU debugger.

  3.    Copyright (C) 1986-2015 Free Software Foundation, Inc.

  5.    This file is part of GDB.

  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.

  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.

  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/>.  */

  20. #ifndef COMMON_EXCEPTIONS_H
  21. ‌#define COMMON_EXCEPTIONS_H

  23. #include "gdb_setjmp.h"

  25. /* Reasons for calling throw_exceptions().  NOTE: all reason values
  26.    must be less than zero.  enum value 0 is reserved for internal use
  27.    as the return value from an initial setjmp().  The function
  28.    catch_exceptions() reserves values >= 0 as legal results from its
  29.    wrapped function.  */

  31. ‌enum return_reason
  32.   {
  33.     /* User interrupt.  */
  34.     RETURN_QUIT = -2,
  35.     /* Any other error.  */
  36.     RETURN_ERROR
  37.   };

  39. ‌#define RETURN_MASK(reason)        (1 << (int)(-reason))

  41. typedef enum
  42. {
  43.   RETURN_MASK_QUIT = RETURN_MASK (RETURN_QUIT),
  44.   RETURN_MASK_ERROR = RETURN_MASK (RETURN_ERROR),
  45.   RETURN_MASK_ALL = (RETURN_MASK_QUIT | RETURN_MASK_ERROR)
  46. ‌} return_mask;

  48. /* Describe all exceptions.  */

  50. ‌enum errors {
  51.   GDB_NO_ERROR,

  53.   /* Any generic error, the corresponding text is in
  54.      exception.message.  */
  55.   GENERIC_ERROR,

  57.   /* Something requested was not found.  */
  58.   NOT_FOUND_ERROR,

  60.   /* Thread library lacks support necessary for finding thread local
  61.      storage.  */
  62.   TLS_NO_LIBRARY_SUPPORT_ERROR,

  64.   /* Load module not found while attempting to find thread local storage.  */
  65.   TLS_LOAD_MODULE_NOT_FOUND_ERROR,

  67.   /* Thread local storage has not been allocated yet.  */
  68.   TLS_NOT_ALLOCATED_YET_ERROR,

  70.   /* Something else went wrong while attempting to find thread local
  71.      storage.  The ``struct gdb_exception'' message field provides
  72.      more detail.  */
  73.   TLS_GENERIC_ERROR,

  75.   /* Problem parsing an XML document.  */
  76.   XML_PARSE_ERROR,

  78.   /* Error accessing memory.  */
  79.   MEMORY_ERROR,

  81.   /* Value not available.  E.g., a register was not collected in a
  82.      traceframe.  */
  83.   NOT_AVAILABLE_ERROR,

  85.   /* Value was optimized out.  Note: if the value was a register, this
  86.      means the register was not saved in the frame.  */
  87.   OPTIMIZED_OUT_ERROR,

  89.   /* DW_OP_GNU_entry_value resolving failed.  */
  90.   NO_ENTRY_VALUE_ERROR,

  92.   /* Target throwing an error has been closed.  Current command should be
  93.      aborted as the inferior state is no longer valid.  */
  94.   TARGET_CLOSE_ERROR,

  96.   /* An undefined command was executed.  */
  97.   UNDEFINED_COMMAND_ERROR,

  99.   /* Requested feature, method, mechanism, etc. is not supported.  */
  100.   NOT_SUPPORTED_ERROR,

  102.   /* Add more errors here.  */
  103.   NR_ERRORS
  104. };

  106. ‌struct gdb_exception
  107. {
  108.   enum return_reason reason;
  109.   enum errors error;
  110.   const char *message;
  111. };

  113. /* Functions to drive the exceptions state machine.  Though declared
  114.    here by necessity, these functions should be considered internal to
  115.    the exceptions subsystem and not used other than via the TRY_CATCH
  116.    macro defined below.  */

  118. extern SIGJMP_BUF *exceptions_state_mc_init (volatile struct
  119.                                              gdb_exception *exception,
  120.                                              return_mask mask);
  121. extern int exceptions_state_mc_action_iter (void);
  122. extern int exceptions_state_mc_action_iter_1 (void);

  124. /* Macro to wrap up standard try/catch behavior.

  126.    The double loop lets us correctly handle code "break"ing out of the
  127.    try catch block.  (It works as the "break" only exits the inner
  128.    "while" loop, the outer for loop detects this handling it
  129.    correctly.)  Of course "return" and "goto" are not so lucky.

  131.    For instance:

  133.    *INDENT-OFF*

  135.    volatile struct gdb_exception e;
  136.    TRY_CATCH (e, RETURN_MASK_ERROR)
  137.      {
  138.      }
  139.    switch (e.reason)
  140.      {
  141.      case RETURN_ERROR: ...
  142.      }

  144.   */

  146. ‌#define TRY_CATCH(EXCEPTION,MASK) \
  147.      { \
  148.        SIGJMP_BUF *buf = \
  149.          exceptions_state_mc_init (&(EXCEPTION), (MASK)); \
  150.        SIGSETJMP (*buf); \
  151.      } \
  152.      while (exceptions_state_mc_action_iter ()) \
  153.        while (exceptions_state_mc_action_iter_1 ())

  155. /* *INDENT-ON* */

  157. /* Hook to allow client-specific actions to be performed prior to
  158.    throwing an exception.  This function must be provided by the
  159.    client, and will be called before any cleanups are run.  */

  161. extern void prepare_to_throw_exception (void);

  163. /* Throw an exception (as described by "struct gdb_exception").  Will
  164.    execute a LONG JUMP to the inner most containing exception handler
  165.    established using catch_exceptions() (or similar).

  167.    Code normally throws an exception using error() et.al.  For various
  168.    reaons, GDB also contains code that throws an exception directly.
  169.    For instance, the remote*.c targets contain CNTRL-C signal handlers
  170.    that propogate the QUIT event up the exception chain.  ``This could
  171.    be a good thing or a dangerous thing.'' -- the Existential
  172.    Wombat.  */

  174. extern void throw_exception (struct gdb_exception exception)
  175.      ATTRIBUTE_NORETURN;
  176. extern void throw_verror (enum errors, const char *fmt, va_list ap)
  177.      ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
  178. extern void throw_vquit (const char *fmt, va_list ap)
  179.      ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
  180. extern void throw_error (enum errors error, const char *fmt, ...)
  181.      ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
  182. extern void throw_quit (const char *fmt, ...)
  183.      ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2);

  185. #endif /* COMMON_EXCEPTIONS_H */