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

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

   Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
   1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
   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 3 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, see <http://www.gnu.org/licenses/>.  */

#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 {
  GDB_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,

  /* Problem parsing an XML document.  */
  XML_PARSE_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 ATTR_FORMAT (printf, 2, 0);
extern NORETURN void throw_vfatal (const char *fmt, va_list ap)
     ATTR_NORETURN ATTR_FORMAT (printf, 1, 0);
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.
60250e8b AC	2
6aba47ca	3	Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
9b254dd1	4	1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
7b871fab	5	Free 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
a9762ec7	11	the Free Software Foundation; either version 3 of the License, or
60250e8b AC	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
a9762ec7	20	along with this program. If not, see <http://www.gnu.org/licenses/>. */
60250e8b AC	21
	22	#ifndef EXCEPTIONS_H
	23	#define EXCEPTIONS_H
	24
e74e72b4	25	#include "ui-out.h"
6941d02a AC	26	#include <setjmp.h>
6941d02a AC	27
2a78bfb5	28	/* Reasons for calling throw_exceptions(). NOTE: all reason values
60250e8b AC	29	must be less than zero. enum value 0 is reserved for internal use
	30	as the return value from an initial setjmp(). The function
	31	catch_exceptions() reserves values >= 0 as legal results from its
	32	wrapped function. */
	33
	34	enum return_reason
	35	{
	36	/* User interrupt. */
	37	RETURN_QUIT = -2,
	38	/* Any other error. */
	39	RETURN_ERROR
	40	};
	41
	42	#define RETURN_MASK(reason) (1 << (int)(-reason))
	43	#define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT)
	44	#define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR)
	45	#define RETURN_MASK_ALL (RETURN_MASK_QUIT \| RETURN_MASK_ERROR)
	46	typedef int return_mask;
	47
2a78bfb5 AC	48	/* Describe all exceptions. */
	49
	50	enum errors {
7b871fab	51	GDB_NO_ERROR,
2a78bfb5 AC	52	/* Any generic error, the corresponding text is in
	53	exception.message. */
	54	GENERIC_ERROR,
05ff989b	55	NOT_FOUND_ERROR,
93ad78a7 KB	56
	57	/* Thread library lacks support necessary for finding thread local
	58	storage. */
	59	TLS_NO_LIBRARY_SUPPORT_ERROR,
	60
	61	/* Load module not found while attempting to find thread local storage. */
	62	TLS_LOAD_MODULE_NOT_FOUND_ERROR,
	63
	64	/* Thread local storage has not been allocated yet. */
	65	TLS_NOT_ALLOCATED_YET_ERROR,
	66
	67	/* Something else went wrong while attempting to find thread local
71fff37b AC	68	storage. The ``struct gdb_exception'' message field provides
71fff37b AC	69	more detail. */
93ad78a7	70	TLS_GENERIC_ERROR,
fd79ecee DJ	71
	72	/* Problem parsing an XML document. */
	73	XML_PARSE_ERROR,
93ad78a7	74
2a78bfb5 AC	75	/* Add more errors here. */
	76	NR_ERRORS
	77	};
	78
71fff37b	79	struct gdb_exception
2a78bfb5 AC	80	{
	81	enum return_reason reason;
	82	enum errors error;
b315da38	83	const char *message;
2a78bfb5 AC	84	};
2a78bfb5 AC	85
c1043fc2	86	/* A pre-defined non-exception. */
71fff37b	87	extern const struct gdb_exception exception_none;
c1043fc2	88
6941d02a AC	89	/* Wrap set/long jmp so that it's more portable (internal to
	90	exceptions). */
	91
	92	#if defined(HAVE_SIGSETJMP)
	93	#define EXCEPTIONS_SIGJMP_BUF sigjmp_buf
	94	#define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1)
	95	#define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val))
	96	#else
	97	#define EXCEPTIONS_SIGJMP_BUF jmp_buf
	98	#define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf)
	99	#define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val))
	100	#endif
	101
	102	/* Functions to drive the exceptions state m/c (internal to
	103	exceptions). */
	104	EXCEPTIONS_SIGJMP_BUF exceptions_state_mc_init (struct ui_out func_uiout,
71fff37b	105	volatile struct gdb_exception *
6941d02a AC	106	exception,
	107	return_mask mask);
	108	int exceptions_state_mc_action_iter (void);
	109	int exceptions_state_mc_action_iter_1 (void);
	110
	111	/* Macro to wrap up standard try/catch behavior.
	112
	113	The double loop lets us correctly handle code "break"ing out of the
	114	try catch block. (It works as the "break" only exits the inner
	115	"while" loop, the outer for loop detects this handling it
	116	correctly.) Of course "return" and "goto" are not so lucky.
	117
	118	For instance:
	119
	120	INDENT-OFF
	121
71fff37b	122	volatile struct gdb_exception e;
6941d02a AC	123	TRY_CATCH (e, RETURN_MASK_ERROR)
	124	{
	125	}
	126	switch (e.reason)
	127	{
	128	case RETURN_ERROR: ...
	129	}
	130
	131	*/
	132
	133	#define TRY_CATCH(EXCEPTION,MASK) \
8d19ca47 CV	134	{ \
	135	EXCEPTIONS_SIGJMP_BUF *buf = \
	136	exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \
	137	EXCEPTIONS_SIGSETJMP (*buf); \
	138	} \
	139	while (exceptions_state_mc_action_iter ()) \
	140	while (exceptions_state_mc_action_iter_1 ())
6941d02a AC	141
	142	/* INDENT-ON */
	143
	144
8a076db9	145	/* If E is an exception, print it's error message on the specified
9cbc821d	146	stream. for _fprintf, prefix the message with PREFIX... */
71fff37b AC	147	extern void exception_print (struct ui_file *file, struct gdb_exception e);
71fff37b AC	148	extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
9cbc821d AC	149	const char *prefix,
9cbc821d AC	150	...) ATTR_FORMAT (printf, 3, 4);
8a076db9	151
71fff37b	152	/* Throw an exception (as described by "struct gdb_exception"). Will
2a78bfb5 AC	153	execute a LONG JUMP to the inner most containing exception handler
2a78bfb5 AC	154	established using catch_exceptions() (or similar).
60250e8b AC	155
	156	Code normally throws an exception using error() et.al. For various
	157	reaons, GDB also contains code that throws an exception directly.
	158	For instance, the remote*.c targets contain CNTRL-C signal handlers
	159	that propogate the QUIT event up the exception chain. ``This could
2a78bfb5 AC	160	be a good thing or a dangerous thing.'' -- the Existential
	161	Wombat. */
	162
71fff37b	163	extern NORETURN void throw_exception (struct gdb_exception exception) ATTR_NORETURN;
bee0189a DJ	164	extern NORETURN void throw_verror (enum errors, const char *fmt, va_list ap)
	165	ATTR_NORETURN ATTR_FORMAT (printf, 2, 0);
	166	extern NORETURN void throw_vfatal (const char *fmt, va_list ap)
	167	ATTR_NORETURN ATTR_FORMAT (printf, 1, 0);
05ff989b AC	168	extern NORETURN void throw_error (enum errors error, const char *fmt,
05ff989b AC	169	...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3);
60250e8b	170
315a522e AC	171	/* Instead of deprecated_throw_reason, code should use catch_exception
	172	and throw_exception. */
	173	extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN;
	174
60250e8b AC	175	/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
	176	handler. If an exception (enum return_reason) is thrown using
	177	throw_exception() than all cleanups installed since
	178	catch_exceptions() was entered are invoked, the (-ve) exception
	179	value is then returned by catch_exceptions. If FUNC() returns
	180	normally (with a postive or zero return value) then that value is
	181	returned by catch_exceptions(). It is an internal_error() for
	182	FUNC() to return a negative value.
	183
	184	For the period of the FUNC() call: UIOUT is installed as the output
	185	builder; ERRSTRING is installed as the error/quit message; and a
	186	new cleanup_chain is established. The old values are restored
	187	before catch_exceptions() returns.
	188
	189	The variant catch_exceptions_with_msg() is the same as
	190	catch_exceptions() but adds the ability to return an allocated
	191	copy of the gdb error message. This is used when a silent error is
	192	issued and the caller wants to manually issue the error message.
	193
	194	FIXME; cagney/2001-08-13: The need to override the global UIOUT
	195	builder variable should just go away.
	196
	197	This function superseeds catch_errors().
	198
	199	This function uses SETJMP() and LONGJUMP(). */
	200
	201	struct ui_out;
	202	typedef int (catch_exceptions_ftype) (struct ui_out ui_out, void args);
	203	extern int catch_exceptions (struct ui_out *uiout,
	204	catch_exceptions_ftype func, void func_args,
1c3c7ee7	205	return_mask mask);
2a78bfb5	206	typedef void (catch_exception_ftype) (struct ui_out ui_out, void args);
60250e8b AC	207	extern int catch_exceptions_with_msg (struct ui_out *uiout,
	208	catch_exceptions_ftype *func,
	209	void *func_args,
1c3c7ee7	210	char **gdberrmsg,
60250e8b	211	return_mask mask);
8a076db9 AC	212
	213	/* This function, in addition, suppresses the printing of the captured
	214	error message. It's up to the client to print it. */
	215
71fff37b AC	216	extern struct gdb_exception catch_exception (struct ui_out *uiout,
	217	catch_exception_ftype *func,
	218	void *func_args,
	219	return_mask mask);
60250e8b AC	220
	221	/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
	222	otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
	223	probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
	224	value. It's unfortunate that, catch_errors() does not return an
	225	indication of the exact exception that it caught - quit_flag might
	226	help.
	227
	228	This function is superseeded by catch_exceptions(). */
	229
	230	typedef int (catch_errors_ftype) (void *);
	231	extern int catch_errors (catch_errors_ftype , void , char *, return_mask);
	232
	233	/* Template to catch_errors() that wraps calls to command
	234	functions. */
	235
	236	typedef void (catch_command_errors_ftype) (char *, int);
	237	extern int catch_command_errors (catch_command_errors_ftype func, char command, int from_tty, return_mask);
	238
	239	#endif