[thirdparty/binutils-gdb.git] / gdb / exceptions.h

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

   Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
   1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free
   Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#ifndef EXCEPTIONS_H
#define EXCEPTIONS_H

#include "ui-out.h"
#include <setjmp.h>

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

enum return_reason
  {
    /* User interrupt.  */
    RETURN_QUIT = -2,
    /* Any other error.  */
    RETURN_ERROR
  };

#define RETURN_MASK(reason)	(1 << (int)(-reason))
#define RETURN_MASK_QUIT	RETURN_MASK (RETURN_QUIT)
#define RETURN_MASK_ERROR	RETURN_MASK (RETURN_ERROR)
#define RETURN_MASK_ALL		(RETURN_MASK_QUIT | RETURN_MASK_ERROR)
typedef int return_mask;

/* Describe all exceptions.  */

enum errors {
  NO_ERROR,
  /* Any generic error, the corresponding text is in
     exception.message.  */
  GENERIC_ERROR,
  NOT_FOUND_ERROR,

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

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

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

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

  /* Add more errors here.  */
  NR_ERRORS
};

struct gdb_exception
{
  enum return_reason reason;
  enum errors error;
  const char *message;
};

/* A pre-defined non-exception.  */
extern const struct gdb_exception exception_none;

/* Wrap set/long jmp so that it's more portable (internal to
   exceptions).  */

#if defined(HAVE_SIGSETJMP)
#define EXCEPTIONS_SIGJMP_BUF		sigjmp_buf
#define EXCEPTIONS_SIGSETJMP(buf)	sigsetjmp((buf), 1)
#define EXCEPTIONS_SIGLONGJMP(buf,val)	siglongjmp((buf), (val))
#else
#define EXCEPTIONS_SIGJMP_BUF		jmp_buf
#define EXCEPTIONS_SIGSETJMP(buf)	setjmp(buf)
#define EXCEPTIONS_SIGLONGJMP(buf,val)	longjmp((buf), (val))
#endif

/* Functions to drive the exceptions state m/c (internal to
   exceptions).  */
EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (struct ui_out *func_uiout,
						 volatile struct gdb_exception *
						 exception,
						 return_mask mask);
int exceptions_state_mc_action_iter (void);
int exceptions_state_mc_action_iter_1 (void);

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

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

   For instance:

   *INDENT-OFF*

   volatile struct gdb_exception e;
   TRY_CATCH (e, RETURN_MASK_ERROR)
     {
     }
   switch (e.reason)
     {
     case RETURN_ERROR: ...
     }

  */

#define TRY_CATCH(EXCEPTION,MASK) \
     { \
       EXCEPTIONS_SIGJMP_BUF *buf = \
	 exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \
       EXCEPTIONS_SIGSETJMP (*buf); \
     } \
     while (exceptions_state_mc_action_iter ()) \
       while (exceptions_state_mc_action_iter_1 ())

/* *INDENT-ON* */


/* If E is an exception, print it's error message on the specified
   stream. for _fprintf, prefix the message with PREFIX...  */
extern void exception_print (struct ui_file *file, struct gdb_exception e);
extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
			       const char *prefix,
			       ...) ATTR_FORMAT (printf, 3, 4);

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

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

extern NORETURN void throw_exception (struct gdb_exception exception) ATTR_NORETURN;
extern NORETURN void throw_verror (enum errors, const char *fmt,
				   va_list ap) ATTR_NORETURN;
extern NORETURN void throw_vfatal (const char *fmt, va_list ap) ATTR_NORETURN;
extern NORETURN void throw_error (enum errors error, const char *fmt,
				  ...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3);

/* Instead of deprecated_throw_reason, code should use catch_exception
   and throw_exception.  */
extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN;

/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
   handler.  If an exception (enum return_reason) is thrown using
   throw_exception() than all cleanups installed since
   catch_exceptions() was entered are invoked, the (-ve) exception
   value is then returned by catch_exceptions.  If FUNC() returns
   normally (with a postive or zero return value) then that value is
   returned by catch_exceptions().  It is an internal_error() for
   FUNC() to return a negative value.

   For the period of the FUNC() call: UIOUT is installed as the output
   builder; ERRSTRING is installed as the error/quit message; and a
   new cleanup_chain is established.  The old values are restored
   before catch_exceptions() returns.

   The variant catch_exceptions_with_msg() is the same as
   catch_exceptions() but adds the ability to return an allocated
   copy of the gdb error message.  This is used when a silent error is 
   issued and the caller wants to manually issue the error message.

   FIXME; cagney/2001-08-13: The need to override the global UIOUT
   builder variable should just go away.

   This function superseeds catch_errors().

   This function uses SETJMP() and LONGJUMP().  */

struct ui_out;
typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args);
extern int catch_exceptions (struct ui_out *uiout,
			     catch_exceptions_ftype *func, void *func_args,
			     return_mask mask);
typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args);
extern int catch_exceptions_with_msg (struct ui_out *uiout,
			     	      catch_exceptions_ftype *func, 
			     	      void *func_args,
			     	      char **gdberrmsg,
				      return_mask mask);

/* This function, in addition, suppresses the printing of the captured
   error message.  It's up to the client to print it.  */

extern struct gdb_exception catch_exception (struct ui_out *uiout,
					     catch_exception_ftype *func,
					     void *func_args,
					     return_mask mask);

/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
   otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
   probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
   value. It's unfortunate that, catch_errors() does not return an
   indication of the exact exception that it caught - quit_flag might
   help.

   This function is superseeded by catch_exceptions().  */

typedef int (catch_errors_ftype) (void *);
extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask);

/* Template to catch_errors() that wraps calls to command
   functions. */

typedef void (catch_command_errors_ftype) (char *, int);
extern int catch_command_errors (catch_command_errors_ftype *func, char *command, int from_tty, return_mask);

#endif
Commit	Line	Data
60250e8b AC	1	/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
	2
	3	Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
05ff989b AC	4	1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free
05ff989b AC	5	Software Foundation, Inc.
60250e8b AC	6
	7	This file is part of GDB.
	8
	9	This program is free software; you can redistribute it and/or modify
	10	it under the terms of the GNU General Public License as published by
	11	the Free Software Foundation; either version 2 of the License, or
	12	(at your option) any later version.
	13
	14	This program is distributed in the hope that it will be useful,
	15	but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	GNU General Public License for more details.
	18
	19	You should have received a copy of the GNU General Public License
	20	along with this program; if not, write to the Free Software
	21	Foundation, Inc., 59 Temple Place - Suite 330,
	22	Boston, MA 02111-1307, USA. */
	23
	24	#ifndef EXCEPTIONS_H
	25	#define EXCEPTIONS_H
	26
e74e72b4	27	#include "ui-out.h"
6941d02a AC	28	#include <setjmp.h>
6941d02a AC	29
2a78bfb5	30	/* Reasons for calling throw_exceptions(). NOTE: all reason values
60250e8b AC	31	must be less than zero. enum value 0 is reserved for internal use
	32	as the return value from an initial setjmp(). The function
	33	catch_exceptions() reserves values >= 0 as legal results from its
	34	wrapped function. */
	35
	36	enum return_reason
	37	{
	38	/* User interrupt. */
	39	RETURN_QUIT = -2,
	40	/* Any other error. */
	41	RETURN_ERROR
	42	};
	43
	44	#define RETURN_MASK(reason) (1 << (int)(-reason))
	45	#define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT)
	46	#define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR)
	47	#define RETURN_MASK_ALL (RETURN_MASK_QUIT \| RETURN_MASK_ERROR)
	48	typedef int return_mask;
	49
2a78bfb5 AC	50	/* Describe all exceptions. */
	51
	52	enum errors {
	53	NO_ERROR,
	54	/* Any generic error, the corresponding text is in
	55	exception.message. */
	56	GENERIC_ERROR,
05ff989b	57	NOT_FOUND_ERROR,
93ad78a7 KB	58
	59	/* Thread library lacks support necessary for finding thread local
	60	storage. */
	61	TLS_NO_LIBRARY_SUPPORT_ERROR,
	62
	63	/* Load module not found while attempting to find thread local storage. */
	64	TLS_LOAD_MODULE_NOT_FOUND_ERROR,
	65
	66	/* Thread local storage has not been allocated yet. */
	67	TLS_NOT_ALLOCATED_YET_ERROR,
	68
	69	/* Something else went wrong while attempting to find thread local
71fff37b AC	70	storage. The ``struct gdb_exception'' message field provides
71fff37b AC	71	more detail. */
93ad78a7 KB	72	TLS_GENERIC_ERROR,
93ad78a7 KB	73
2a78bfb5 AC	74	/* Add more errors here. */
	75	NR_ERRORS
	76	};
	77
71fff37b	78	struct gdb_exception
2a78bfb5 AC	79	{
	80	enum return_reason reason;
	81	enum errors error;
b315da38	82	const char *message;
2a78bfb5 AC	83	};
2a78bfb5 AC	84
c1043fc2	85	/* A pre-defined non-exception. */
71fff37b	86	extern const struct gdb_exception exception_none;
c1043fc2	87
6941d02a AC	88	/* Wrap set/long jmp so that it's more portable (internal to
	89	exceptions). */
	90
	91	#if defined(HAVE_SIGSETJMP)
	92	#define EXCEPTIONS_SIGJMP_BUF sigjmp_buf
	93	#define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1)
	94	#define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val))
	95	#else
	96	#define EXCEPTIONS_SIGJMP_BUF jmp_buf
	97	#define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf)
	98	#define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val))
	99	#endif
	100
	101	/* Functions to drive the exceptions state m/c (internal to
	102	exceptions). */
	103	EXCEPTIONS_SIGJMP_BUF exceptions_state_mc_init (struct ui_out func_uiout,
71fff37b	104	volatile struct gdb_exception *
6941d02a AC	105	exception,
	106	return_mask mask);
	107	int exceptions_state_mc_action_iter (void);
	108	int exceptions_state_mc_action_iter_1 (void);
	109
	110	/* Macro to wrap up standard try/catch behavior.
	111
	112	The double loop lets us correctly handle code "break"ing out of the
	113	try catch block. (It works as the "break" only exits the inner
	114	"while" loop, the outer for loop detects this handling it
	115	correctly.) Of course "return" and "goto" are not so lucky.
	116
	117	For instance:
	118
	119	INDENT-OFF
	120
71fff37b	121	volatile struct gdb_exception e;
6941d02a AC	122	TRY_CATCH (e, RETURN_MASK_ERROR)
	123	{
	124	}
	125	switch (e.reason)
	126	{
	127	case RETURN_ERROR: ...
	128	}
	129
	130	*/
	131
	132	#define TRY_CATCH(EXCEPTION,MASK) \
8d19ca47 CV	133	{ \
	134	EXCEPTIONS_SIGJMP_BUF *buf = \
	135	exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \
	136	EXCEPTIONS_SIGSETJMP (*buf); \
	137	} \
	138	while (exceptions_state_mc_action_iter ()) \
	139	while (exceptions_state_mc_action_iter_1 ())
6941d02a AC	140
	141	/* INDENT-ON */
	142
	143
8a076db9	144	/* If E is an exception, print it's error message on the specified
9cbc821d	145	stream. for _fprintf, prefix the message with PREFIX... */
71fff37b AC	146	extern void exception_print (struct ui_file *file, struct gdb_exception e);
71fff37b AC	147	extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
9cbc821d AC	148	const char *prefix,
9cbc821d AC	149	...) ATTR_FORMAT (printf, 3, 4);
8a076db9	150
71fff37b	151	/* Throw an exception (as described by "struct gdb_exception"). Will
2a78bfb5 AC	152	execute a LONG JUMP to the inner most containing exception handler
2a78bfb5 AC	153	established using catch_exceptions() (or similar).
60250e8b AC	154
	155	Code normally throws an exception using error() et.al. For various
	156	reaons, GDB also contains code that throws an exception directly.
	157	For instance, the remote*.c targets contain CNTRL-C signal handlers
	158	that propogate the QUIT event up the exception chain. ``This could
2a78bfb5 AC	159	be a good thing or a dangerous thing.'' -- the Existential
	160	Wombat. */
	161
71fff37b	162	extern NORETURN void throw_exception (struct gdb_exception exception) ATTR_NORETURN;
6b1b7650 AC	163	extern NORETURN void throw_verror (enum errors, const char *fmt,
	164	va_list ap) ATTR_NORETURN;
	165	extern NORETURN void throw_vfatal (const char *fmt, va_list ap) ATTR_NORETURN;
05ff989b AC	166	extern NORETURN void throw_error (enum errors error, const char *fmt,
05ff989b AC	167	...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3);
60250e8b	168
315a522e AC	169	/* Instead of deprecated_throw_reason, code should use catch_exception
	170	and throw_exception. */
	171	extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN;
	172
60250e8b AC	173	/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
	174	handler. If an exception (enum return_reason) is thrown using
	175	throw_exception() than all cleanups installed since
	176	catch_exceptions() was entered are invoked, the (-ve) exception
	177	value is then returned by catch_exceptions. If FUNC() returns
	178	normally (with a postive or zero return value) then that value is
	179	returned by catch_exceptions(). It is an internal_error() for
	180	FUNC() to return a negative value.
	181
	182	For the period of the FUNC() call: UIOUT is installed as the output
	183	builder; ERRSTRING is installed as the error/quit message; and a
	184	new cleanup_chain is established. The old values are restored
	185	before catch_exceptions() returns.
	186
	187	The variant catch_exceptions_with_msg() is the same as
	188	catch_exceptions() but adds the ability to return an allocated
	189	copy of the gdb error message. This is used when a silent error is
	190	issued and the caller wants to manually issue the error message.
	191
	192	FIXME; cagney/2001-08-13: The need to override the global UIOUT
	193	builder variable should just go away.
	194
	195	This function superseeds catch_errors().
	196
	197	This function uses SETJMP() and LONGJUMP(). */
	198
	199	struct ui_out;
	200	typedef int (catch_exceptions_ftype) (struct ui_out ui_out, void args);
	201	extern int catch_exceptions (struct ui_out *uiout,
	202	catch_exceptions_ftype func, void func_args,
1c3c7ee7	203	return_mask mask);
2a78bfb5	204	typedef void (catch_exception_ftype) (struct ui_out ui_out, void args);
60250e8b AC	205	extern int catch_exceptions_with_msg (struct ui_out *uiout,
	206	catch_exceptions_ftype *func,
	207	void *func_args,
1c3c7ee7	208	char **gdberrmsg,
60250e8b	209	return_mask mask);
8a076db9 AC	210
	211	/* This function, in addition, suppresses the printing of the captured
	212	error message. It's up to the client to print it. */
	213
71fff37b AC	214	extern struct gdb_exception catch_exception (struct ui_out *uiout,
	215	catch_exception_ftype *func,
	216	void *func_args,
	217	return_mask mask);
60250e8b AC	218
	219	/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
	220	otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
	221	probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
	222	value. It's unfortunate that, catch_errors() does not return an
	223	indication of the exact exception that it caught - quit_flag might
	224	help.
	225
	226	This function is superseeded by catch_exceptions(). */
	227
	228	typedef int (catch_errors_ftype) (void *);
	229	extern int catch_errors (catch_errors_ftype , void , char *, return_mask);
	230
	231	/* Template to catch_errors() that wraps calls to command
	232	functions. */
	233
	234	typedef void (catch_command_errors_ftype) (char *, int);
	235	extern int catch_command_errors (catch_command_errors_ftype func, char command, int from_tty, return_mask);
	236
	237	#endif