[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,
   2009, 2010, 2011 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,

  /* Error accessing memory.  */
  MEMORY_ERROR,

  /* Feature is not supported in this copy of GDB.  */
  UNSUPPORTED_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,
			       ...) ATTRIBUTE_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 void throw_exception (struct gdb_exception exception)
     ATTRIBUTE_NORETURN;
extern void throw_verror (enum errors, const char *fmt, va_list ap)
     ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
extern void throw_vfatal (const char *fmt, va_list ap)
     ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
extern void throw_error (enum errors error, const char *fmt, ...)
     ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);

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

   MASK specifies what to catch; it is normally set to
   RETURN_MASK_ALL, if for no other reason than that the code which
   calls catch_errors might not be set up to deal with a quit which
   isn't caught.  But if the code can deal with it, it generally
   should be RETURN_MASK_ERROR, unless for some reason it is more
   useful to abort only the portion of the operation inside the
   catch_errors.  Note that quit should return to the command line
   fairly quickly, even if some further processing is being done.

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

   This function supersedes 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 superseded 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,
0fb0cc75	4	1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
7b6bb8da	5	2009, 2010, 2011 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,
ccc57cf9 PA	74
	75	/* Error accessing memory. */
	76	MEMORY_ERROR,
93ad78a7	77
973817a3 JB	78	/* Feature is not supported in this copy of GDB. */
	79	UNSUPPORTED_ERROR,
	80
2a78bfb5 AC	81	/* Add more errors here. */
	82	NR_ERRORS
	83	};
	84
71fff37b	85	struct gdb_exception
2a78bfb5 AC	86	{
	87	enum return_reason reason;
	88	enum errors error;
b315da38	89	const char *message;
2a78bfb5 AC	90	};
2a78bfb5 AC	91
c1043fc2	92	/* A pre-defined non-exception. */
71fff37b	93	extern const struct gdb_exception exception_none;
c1043fc2	94
6941d02a AC	95	/* Wrap set/long jmp so that it's more portable (internal to
	96	exceptions). */
	97
	98	#if defined(HAVE_SIGSETJMP)
	99	#define EXCEPTIONS_SIGJMP_BUF sigjmp_buf
	100	#define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1)
	101	#define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val))
	102	#else
	103	#define EXCEPTIONS_SIGJMP_BUF jmp_buf
	104	#define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf)
	105	#define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val))
	106	#endif
	107
	108	/* Functions to drive the exceptions state m/c (internal to
	109	exceptions). */
	110	EXCEPTIONS_SIGJMP_BUF exceptions_state_mc_init (struct ui_out func_uiout,
3e43a32a MS	111	volatile struct
3e43a32a MS	112	gdb_exception *exception,
6941d02a AC	113	return_mask mask);
	114	int exceptions_state_mc_action_iter (void);
	115	int exceptions_state_mc_action_iter_1 (void);
	116
	117	/* Macro to wrap up standard try/catch behavior.
	118
	119	The double loop lets us correctly handle code "break"ing out of the
	120	try catch block. (It works as the "break" only exits the inner
	121	"while" loop, the outer for loop detects this handling it
	122	correctly.) Of course "return" and "goto" are not so lucky.
	123
	124	For instance:
	125
	126	INDENT-OFF
	127
71fff37b	128	volatile struct gdb_exception e;
6941d02a AC	129	TRY_CATCH (e, RETURN_MASK_ERROR)
	130	{
	131	}
	132	switch (e.reason)
	133	{
	134	case RETURN_ERROR: ...
	135	}
	136
	137	*/
	138
	139	#define TRY_CATCH(EXCEPTION,MASK) \
8d19ca47 CV	140	{ \
	141	EXCEPTIONS_SIGJMP_BUF *buf = \
	142	exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \
	143	EXCEPTIONS_SIGSETJMP (*buf); \
	144	} \
	145	while (exceptions_state_mc_action_iter ()) \
	146	while (exceptions_state_mc_action_iter_1 ())
6941d02a AC	147
	148	/* INDENT-ON */
	149
	150
8a076db9	151	/* If E is an exception, print it's error message on the specified
0963b4bd	152	stream. For _fprintf, prefix the message with PREFIX... */
71fff37b AC	153	extern void exception_print (struct ui_file *file, struct gdb_exception e);
71fff37b AC	154	extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
9cbc821d	155	const char *prefix,
a0b31db1	156	...) ATTRIBUTE_PRINTF (3, 4);
8a076db9	157
71fff37b	158	/* Throw an exception (as described by "struct gdb_exception"). Will
2a78bfb5 AC	159	execute a LONG JUMP to the inner most containing exception handler
2a78bfb5 AC	160	established using catch_exceptions() (or similar).
60250e8b AC	161
	162	Code normally throws an exception using error() et.al. For various
	163	reaons, GDB also contains code that throws an exception directly.
	164	For instance, the remote*.c targets contain CNTRL-C signal handlers
	165	that propogate the QUIT event up the exception chain. ``This could
2a78bfb5 AC	166	be a good thing or a dangerous thing.'' -- the Existential
	167	Wombat. */
	168
3e43a32a MS	169	extern void throw_exception (struct gdb_exception exception)
3e43a32a MS	170	ATTRIBUTE_NORETURN;
c25c4a8b JK	171	extern void throw_verror (enum errors, const char *fmt, va_list ap)
	172	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
	173	extern void throw_vfatal (const char *fmt, va_list ap)
	174	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
	175	extern void throw_error (enum errors error, const char *fmt, ...)
	176	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
60250e8b	177
315a522e AC	178	/* Instead of deprecated_throw_reason, code should use catch_exception
315a522e AC	179	and throw_exception. */
c25c4a8b JK	180	extern void deprecated_throw_reason (enum return_reason reason)
c25c4a8b JK	181	ATTRIBUTE_NORETURN;
315a522e	182
60250e8b AC	183	/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
	184	handler. If an exception (enum return_reason) is thrown using
	185	throw_exception() than all cleanups installed since
	186	catch_exceptions() was entered are invoked, the (-ve) exception
	187	value is then returned by catch_exceptions. If FUNC() returns
787274f0	188	normally (with a positive or zero return value) then that value is
60250e8b AC	189	returned by catch_exceptions(). It is an internal_error() for
	190	FUNC() to return a negative value.
	191
	192	For the period of the FUNC() call: UIOUT is installed as the output
	193	builder; ERRSTRING is installed as the error/quit message; and a
	194	new cleanup_chain is established. The old values are restored
	195	before catch_exceptions() returns.
	196
	197	The variant catch_exceptions_with_msg() is the same as
	198	catch_exceptions() but adds the ability to return an allocated
	199	copy of the gdb error message. This is used when a silent error is
	200	issued and the caller wants to manually issue the error message.
	201
787274f0 DE	202	MASK specifies what to catch; it is normally set to
	203	RETURN_MASK_ALL, if for no other reason than that the code which
	204	calls catch_errors might not be set up to deal with a quit which
	205	isn't caught. But if the code can deal with it, it generally
	206	should be RETURN_MASK_ERROR, unless for some reason it is more
	207	useful to abort only the portion of the operation inside the
	208	catch_errors. Note that quit should return to the command line
	209	fairly quickly, even if some further processing is being done.
	210
60250e8b AC	211	FIXME; cagney/2001-08-13: The need to override the global UIOUT
	212	builder variable should just go away.
	213
787274f0	214	This function supersedes catch_errors().
60250e8b AC	215
	216	This function uses SETJMP() and LONGJUMP(). */
	217
	218	struct ui_out;
	219	typedef int (catch_exceptions_ftype) (struct ui_out ui_out, void args);
	220	extern int catch_exceptions (struct ui_out *uiout,
	221	catch_exceptions_ftype func, void func_args,
1c3c7ee7	222	return_mask mask);
2a78bfb5	223	typedef void (catch_exception_ftype) (struct ui_out ui_out, void args);
60250e8b AC	224	extern int catch_exceptions_with_msg (struct ui_out *uiout,
	225	catch_exceptions_ftype *func,
	226	void *func_args,
1c3c7ee7	227	char **gdberrmsg,
60250e8b	228	return_mask mask);
8a076db9 AC	229
	230	/* This function, in addition, suppresses the printing of the captured
	231	error message. It's up to the client to print it. */
	232
71fff37b AC	233	extern struct gdb_exception catch_exception (struct ui_out *uiout,
	234	catch_exception_ftype *func,
	235	void *func_args,
	236	return_mask mask);
60250e8b AC	237
60250e8b AC	238	/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
0963b4bd	239	otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
60250e8b	240	probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
0963b4bd	241	value. It's unfortunate that, catch_errors() does not return an
60250e8b AC	242	indication of the exact exception that it caught - quit_flag might
	243	help.
	244
787274f0	245	This function is superseded by catch_exceptions(). */
60250e8b AC	246
	247	typedef int (catch_errors_ftype) (void *);
	248	extern int catch_errors (catch_errors_ftype , void , char *, return_mask);
	249
	250	/* Template to catch_errors() that wraps calls to command
0963b4bd	251	functions. */
60250e8b AC	252
60250e8b AC	253	typedef void (catch_command_errors_ftype) (char *, int);
3e43a32a MS	254	extern int catch_command_errors (catch_command_errors_ftype *func,
3e43a32a MS	255	char *command, int from_tty, return_mask);
60250e8b AC	256
60250e8b AC	257	#endif