[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,

  /* Something requested was not found.  */
  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,

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

  /* DW_OP_GNU_entry_value resolving failed.  */
  NO_ENTRY_VALUE_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 (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 (&(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
   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);

/* 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,
8af8e3bc	52
2a78bfb5 AC	53	/* Any generic error, the corresponding text is in
	54	exception.message. */
	55	GENERIC_ERROR,
8af8e3bc PA	56
8af8e3bc PA	57	/* Something requested was not found. */
05ff989b	58	NOT_FOUND_ERROR,
93ad78a7 KB	59
	60	/* Thread library lacks support necessary for finding thread local
	61	storage. */
	62	TLS_NO_LIBRARY_SUPPORT_ERROR,
	63
	64	/* Load module not found while attempting to find thread local storage. */
	65	TLS_LOAD_MODULE_NOT_FOUND_ERROR,
	66
	67	/* Thread local storage has not been allocated yet. */
	68	TLS_NOT_ALLOCATED_YET_ERROR,
	69
	70	/* Something else went wrong while attempting to find thread local
71fff37b AC	71	storage. The ``struct gdb_exception'' message field provides
71fff37b AC	72	more detail. */
93ad78a7	73	TLS_GENERIC_ERROR,
fd79ecee DJ	74
	75	/* Problem parsing an XML document. */
	76	XML_PARSE_ERROR,
ccc57cf9 PA	77
	78	/* Error accessing memory. */
	79	MEMORY_ERROR,
93ad78a7	80
973817a3 JB	81	/* Feature is not supported in this copy of GDB. */
	82	UNSUPPORTED_ERROR,
	83
8af8e3bc PA	84	/* Value not available. E.g., a register was not collected in a
	85	traceframe. */
	86	NOT_AVAILABLE_ERROR,
	87
8e3b41a9 JK	88	/* DW_OP_GNU_entry_value resolving failed. */
	89	NO_ENTRY_VALUE_ERROR,
	90
2a78bfb5 AC	91	/* Add more errors here. */
	92	NR_ERRORS
	93	};
	94
71fff37b	95	struct gdb_exception
2a78bfb5 AC	96	{
	97	enum return_reason reason;
	98	enum errors error;
b315da38	99	const char *message;
2a78bfb5 AC	100	};
2a78bfb5 AC	101
c1043fc2	102	/* A pre-defined non-exception. */
71fff37b	103	extern const struct gdb_exception exception_none;
c1043fc2	104
6941d02a AC	105	/* Wrap set/long jmp so that it's more portable (internal to
	106	exceptions). */
	107
	108	#if defined(HAVE_SIGSETJMP)
	109	#define EXCEPTIONS_SIGJMP_BUF sigjmp_buf
	110	#define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1)
	111	#define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val))
	112	#else
	113	#define EXCEPTIONS_SIGJMP_BUF jmp_buf
	114	#define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf)
	115	#define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val))
	116	#endif
	117
	118	/* Functions to drive the exceptions state m/c (internal to
	119	exceptions). */
f9679975	120	EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (volatile struct
3e43a32a	121	gdb_exception *exception,
6941d02a AC	122	return_mask mask);
	123	int exceptions_state_mc_action_iter (void);
	124	int exceptions_state_mc_action_iter_1 (void);
	125
	126	/* Macro to wrap up standard try/catch behavior.
	127
	128	The double loop lets us correctly handle code "break"ing out of the
	129	try catch block. (It works as the "break" only exits the inner
	130	"while" loop, the outer for loop detects this handling it
	131	correctly.) Of course "return" and "goto" are not so lucky.
	132
	133	For instance:
	134
	135	INDENT-OFF
	136
71fff37b	137	volatile struct gdb_exception e;
6941d02a AC	138	TRY_CATCH (e, RETURN_MASK_ERROR)
	139	{
	140	}
	141	switch (e.reason)
	142	{
	143	case RETURN_ERROR: ...
	144	}
	145
	146	*/
	147
	148	#define TRY_CATCH(EXCEPTION,MASK) \
8d19ca47 CV	149	{ \
8d19ca47 CV	150	EXCEPTIONS_SIGJMP_BUF *buf = \
f9679975	151	exceptions_state_mc_init (&(EXCEPTION), (MASK)); \
8d19ca47 CV	152	EXCEPTIONS_SIGSETJMP (*buf); \
	153	} \
	154	while (exceptions_state_mc_action_iter ()) \
	155	while (exceptions_state_mc_action_iter_1 ())
6941d02a AC	156
	157	/* INDENT-ON */
	158
	159
8a076db9	160	/* If E is an exception, print it's error message on the specified
0963b4bd	161	stream. For _fprintf, prefix the message with PREFIX... */
71fff37b AC	162	extern void exception_print (struct ui_file *file, struct gdb_exception e);
71fff37b AC	163	extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
9cbc821d	164	const char *prefix,
a0b31db1	165	...) ATTRIBUTE_PRINTF (3, 4);
8a076db9	166
71fff37b	167	/* Throw an exception (as described by "struct gdb_exception"). Will
2a78bfb5 AC	168	execute a LONG JUMP to the inner most containing exception handler
2a78bfb5 AC	169	established using catch_exceptions() (or similar).
60250e8b AC	170
	171	Code normally throws an exception using error() et.al. For various
	172	reaons, GDB also contains code that throws an exception directly.
	173	For instance, the remote*.c targets contain CNTRL-C signal handlers
	174	that propogate the QUIT event up the exception chain. ``This could
2a78bfb5 AC	175	be a good thing or a dangerous thing.'' -- the Existential
	176	Wombat. */
	177
3e43a32a MS	178	extern void throw_exception (struct gdb_exception exception)
3e43a32a MS	179	ATTRIBUTE_NORETURN;
c25c4a8b JK	180	extern void throw_verror (enum errors, const char *fmt, va_list ap)
	181	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
	182	extern void throw_vfatal (const char *fmt, va_list ap)
	183	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
	184	extern void throw_error (enum errors error, const char *fmt, ...)
	185	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
60250e8b	186
04bd08de TT	187	/* Instead of deprecated_throw_reason, code should use
04bd08de TT	188	throw_exception. */
c25c4a8b JK	189	extern void deprecated_throw_reason (enum return_reason reason)
c25c4a8b JK	190	ATTRIBUTE_NORETURN;
315a522e	191
60250e8b AC	192	/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
	193	handler. If an exception (enum return_reason) is thrown using
	194	throw_exception() than all cleanups installed since
	195	catch_exceptions() was entered are invoked, the (-ve) exception
	196	value is then returned by catch_exceptions. If FUNC() returns
787274f0	197	normally (with a positive or zero return value) then that value is
60250e8b AC	198	returned by catch_exceptions(). It is an internal_error() for
	199	FUNC() to return a negative value.
	200
	201	For the period of the FUNC() call: UIOUT is installed as the output
	202	builder; ERRSTRING is installed as the error/quit message; and a
	203	new cleanup_chain is established. The old values are restored
	204	before catch_exceptions() returns.
	205
	206	The variant catch_exceptions_with_msg() is the same as
	207	catch_exceptions() but adds the ability to return an allocated
	208	copy of the gdb error message. This is used when a silent error is
	209	issued and the caller wants to manually issue the error message.
	210
787274f0 DE	211	MASK specifies what to catch; it is normally set to
	212	RETURN_MASK_ALL, if for no other reason than that the code which
	213	calls catch_errors might not be set up to deal with a quit which
	214	isn't caught. But if the code can deal with it, it generally
	215	should be RETURN_MASK_ERROR, unless for some reason it is more
	216	useful to abort only the portion of the operation inside the
	217	catch_errors. Note that quit should return to the command line
	218	fairly quickly, even if some further processing is being done.
	219
60250e8b AC	220	FIXME; cagney/2001-08-13: The need to override the global UIOUT
	221	builder variable should just go away.
	222
787274f0	223	This function supersedes catch_errors().
60250e8b AC	224
	225	This function uses SETJMP() and LONGJUMP(). */
	226
	227	struct ui_out;
	228	typedef int (catch_exceptions_ftype) (struct ui_out ui_out, void args);
	229	extern int catch_exceptions (struct ui_out *uiout,
	230	catch_exceptions_ftype func, void func_args,
1c3c7ee7	231	return_mask mask);
2a78bfb5	232	typedef void (catch_exception_ftype) (struct ui_out ui_out, void args);
60250e8b AC	233	extern int catch_exceptions_with_msg (struct ui_out *uiout,
	234	catch_exceptions_ftype *func,
	235	void *func_args,
1c3c7ee7	236	char **gdberrmsg,
60250e8b	237	return_mask mask);
8a076db9	238
60250e8b	239	/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
0963b4bd	240	otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
60250e8b	241	probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
0963b4bd	242	value. It's unfortunate that, catch_errors() does not return an
60250e8b AC	243	indication of the exact exception that it caught - quit_flag might
	244	help.
	245
787274f0	246	This function is superseded by catch_exceptions(). */
60250e8b AC	247
	248	typedef int (catch_errors_ftype) (void *);
	249	extern int catch_errors (catch_errors_ftype , void , char *, return_mask);
	250
	251	/* Template to catch_errors() that wraps calls to command
0963b4bd	252	functions. */
60250e8b AC	253
60250e8b AC	254	typedef void (catch_command_errors_ftype) (char *, int);
3e43a32a MS	255	extern int catch_command_errors (catch_command_errors_ftype *func,
3e43a32a MS	256	char *command, int from_tty, return_mask);
60250e8b AC	257
60250e8b AC	258	#endif