[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 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,

  /* 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 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 JB	4	1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
0fb0cc75 JB	5	2009 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
2a78bfb5 AC	78	/* Add more errors here. */
	79	NR_ERRORS
	80	};
	81
71fff37b	82	struct gdb_exception
2a78bfb5 AC	83	{
	84	enum return_reason reason;
	85	enum errors error;
b315da38	86	const char *message;
2a78bfb5 AC	87	};
2a78bfb5 AC	88
c1043fc2	89	/* A pre-defined non-exception. */
71fff37b	90	extern const struct gdb_exception exception_none;
c1043fc2	91
6941d02a AC	92	/* Wrap set/long jmp so that it's more portable (internal to
	93	exceptions). */
	94
	95	#if defined(HAVE_SIGSETJMP)
	96	#define EXCEPTIONS_SIGJMP_BUF sigjmp_buf
	97	#define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1)
	98	#define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val))
	99	#else
	100	#define EXCEPTIONS_SIGJMP_BUF jmp_buf
	101	#define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf)
	102	#define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val))
	103	#endif
	104
	105	/* Functions to drive the exceptions state m/c (internal to
	106	exceptions). */
	107	EXCEPTIONS_SIGJMP_BUF exceptions_state_mc_init (struct ui_out func_uiout,
71fff37b	108	volatile struct gdb_exception *
6941d02a AC	109	exception,
	110	return_mask mask);
	111	int exceptions_state_mc_action_iter (void);
	112	int exceptions_state_mc_action_iter_1 (void);
	113
	114	/* Macro to wrap up standard try/catch behavior.
	115
	116	The double loop lets us correctly handle code "break"ing out of the
	117	try catch block. (It works as the "break" only exits the inner
	118	"while" loop, the outer for loop detects this handling it
	119	correctly.) Of course "return" and "goto" are not so lucky.
	120
	121	For instance:
	122
	123	INDENT-OFF
	124
71fff37b	125	volatile struct gdb_exception e;
6941d02a AC	126	TRY_CATCH (e, RETURN_MASK_ERROR)
	127	{
	128	}
	129	switch (e.reason)
	130	{
	131	case RETURN_ERROR: ...
	132	}
	133
	134	*/
	135
	136	#define TRY_CATCH(EXCEPTION,MASK) \
8d19ca47 CV	137	{ \
	138	EXCEPTIONS_SIGJMP_BUF *buf = \
	139	exceptions_state_mc_init (uiout, &(EXCEPTION), (MASK)); \
	140	EXCEPTIONS_SIGSETJMP (*buf); \
	141	} \
	142	while (exceptions_state_mc_action_iter ()) \
	143	while (exceptions_state_mc_action_iter_1 ())
6941d02a AC	144
	145	/* INDENT-ON */
	146
	147
8a076db9	148	/* If E is an exception, print it's error message on the specified
9cbc821d	149	stream. for _fprintf, prefix the message with PREFIX... */
71fff37b AC	150	extern void exception_print (struct ui_file *file, struct gdb_exception e);
71fff37b AC	151	extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
9cbc821d AC	152	const char *prefix,
9cbc821d AC	153	...) ATTR_FORMAT (printf, 3, 4);
8a076db9	154
71fff37b	155	/* Throw an exception (as described by "struct gdb_exception"). Will
2a78bfb5 AC	156	execute a LONG JUMP to the inner most containing exception handler
2a78bfb5 AC	157	established using catch_exceptions() (or similar).
60250e8b AC	158
	159	Code normally throws an exception using error() et.al. For various
	160	reaons, GDB also contains code that throws an exception directly.
	161	For instance, the remote*.c targets contain CNTRL-C signal handlers
	162	that propogate the QUIT event up the exception chain. ``This could
2a78bfb5 AC	163	be a good thing or a dangerous thing.'' -- the Existential
	164	Wombat. */
	165
71fff37b	166	extern NORETURN void throw_exception (struct gdb_exception exception) ATTR_NORETURN;
bee0189a DJ	167	extern NORETURN void throw_verror (enum errors, const char *fmt, va_list ap)
	168	ATTR_NORETURN ATTR_FORMAT (printf, 2, 0);
	169	extern NORETURN void throw_vfatal (const char *fmt, va_list ap)
	170	ATTR_NORETURN ATTR_FORMAT (printf, 1, 0);
05ff989b AC	171	extern NORETURN void throw_error (enum errors error, const char *fmt,
05ff989b AC	172	...) ATTR_NORETURN ATTR_FORMAT (printf, 2, 3);
60250e8b	173
315a522e AC	174	/* Instead of deprecated_throw_reason, code should use catch_exception
	175	and throw_exception. */
	176	extern NORETURN void deprecated_throw_reason (enum return_reason reason) ATTR_NORETURN;
	177
60250e8b AC	178	/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
	179	handler. If an exception (enum return_reason) is thrown using
	180	throw_exception() than all cleanups installed since
	181	catch_exceptions() was entered are invoked, the (-ve) exception
	182	value is then returned by catch_exceptions. If FUNC() returns
787274f0	183	normally (with a positive or zero return value) then that value is
60250e8b AC	184	returned by catch_exceptions(). It is an internal_error() for
	185	FUNC() to return a negative value.
	186
	187	For the period of the FUNC() call: UIOUT is installed as the output
	188	builder; ERRSTRING is installed as the error/quit message; and a
	189	new cleanup_chain is established. The old values are restored
	190	before catch_exceptions() returns.
	191
	192	The variant catch_exceptions_with_msg() is the same as
	193	catch_exceptions() but adds the ability to return an allocated
	194	copy of the gdb error message. This is used when a silent error is
	195	issued and the caller wants to manually issue the error message.
	196
787274f0 DE	197	MASK specifies what to catch; it is normally set to
	198	RETURN_MASK_ALL, if for no other reason than that the code which
	199	calls catch_errors might not be set up to deal with a quit which
	200	isn't caught. But if the code can deal with it, it generally
	201	should be RETURN_MASK_ERROR, unless for some reason it is more
	202	useful to abort only the portion of the operation inside the
	203	catch_errors. Note that quit should return to the command line
	204	fairly quickly, even if some further processing is being done.
	205
60250e8b AC	206	FIXME; cagney/2001-08-13: The need to override the global UIOUT
	207	builder variable should just go away.
	208
787274f0	209	This function supersedes catch_errors().
60250e8b AC	210
	211	This function uses SETJMP() and LONGJUMP(). */
	212
	213	struct ui_out;
	214	typedef int (catch_exceptions_ftype) (struct ui_out ui_out, void args);
	215	extern int catch_exceptions (struct ui_out *uiout,
	216	catch_exceptions_ftype func, void func_args,
1c3c7ee7	217	return_mask mask);
2a78bfb5	218	typedef void (catch_exception_ftype) (struct ui_out ui_out, void args);
60250e8b AC	219	extern int catch_exceptions_with_msg (struct ui_out *uiout,
	220	catch_exceptions_ftype *func,
	221	void *func_args,
1c3c7ee7	222	char **gdberrmsg,
60250e8b	223	return_mask mask);
8a076db9 AC	224
	225	/* This function, in addition, suppresses the printing of the captured
	226	error message. It's up to the client to print it. */
	227
71fff37b AC	228	extern struct gdb_exception catch_exception (struct ui_out *uiout,
	229	catch_exception_ftype *func,
	230	void *func_args,
	231	return_mask mask);
60250e8b AC	232
	233	/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
	234	otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
	235	probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
	236	value. It's unfortunate that, catch_errors() does not return an
	237	indication of the exact exception that it caught - quit_flag might
	238	help.
	239
787274f0	240	This function is superseded by catch_exceptions(). */
60250e8b AC	241
	242	typedef int (catch_errors_ftype) (void *);
	243	extern int catch_errors (catch_errors_ftype , void , char *, return_mask);
	244
	245	/* Template to catch_errors() that wraps calls to command
	246	functions. */
	247
	248	typedef void (catch_command_errors_ftype) (char *, int);
	249	extern int catch_command_errors (catch_command_errors_ftype func, char command, int from_tty, return_mask);
	250
	251	#endif