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

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

   Copyright (C) 1986, 1988-2012 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
0b302171	3	Copyright (C) 1986, 1988-2012 Free Software Foundation, Inc.
60250e8b AC	4
	5	This file is part of GDB.
	6
	7	This program is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
a9762ec7	9	the Free Software Foundation; either version 3 of the License, or
60250e8b AC	10	(at your option) any later version.
	11
	12	This program is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
a9762ec7	18	along with this program. If not, see <http://www.gnu.org/licenses/>. */
60250e8b AC	19
	20	#ifndef EXCEPTIONS_H
	21	#define EXCEPTIONS_H
	22
e74e72b4	23	#include "ui-out.h"
6941d02a AC	24	#include <setjmp.h>
6941d02a AC	25
2a78bfb5	26	/* Reasons for calling throw_exceptions(). NOTE: all reason values
60250e8b AC	27	must be less than zero. enum value 0 is reserved for internal use
	28	as the return value from an initial setjmp(). The function
	29	catch_exceptions() reserves values >= 0 as legal results from its
	30	wrapped function. */
	31
	32	enum return_reason
	33	{
	34	/* User interrupt. */
	35	RETURN_QUIT = -2,
	36	/* Any other error. */
	37	RETURN_ERROR
	38	};
	39
	40	#define RETURN_MASK(reason) (1 << (int)(-reason))
	41	#define RETURN_MASK_QUIT RETURN_MASK (RETURN_QUIT)
	42	#define RETURN_MASK_ERROR RETURN_MASK (RETURN_ERROR)
	43	#define RETURN_MASK_ALL (RETURN_MASK_QUIT \| RETURN_MASK_ERROR)
	44	typedef int return_mask;
	45
2a78bfb5 AC	46	/* Describe all exceptions. */
	47
	48	enum errors {
7b871fab	49	GDB_NO_ERROR,
8af8e3bc	50
2a78bfb5 AC	51	/* Any generic error, the corresponding text is in
	52	exception.message. */
	53	GENERIC_ERROR,
8af8e3bc PA	54
8af8e3bc PA	55	/* Something requested was not found. */
05ff989b	56	NOT_FOUND_ERROR,
93ad78a7 KB	57
	58	/* Thread library lacks support necessary for finding thread local
	59	storage. */
	60	TLS_NO_LIBRARY_SUPPORT_ERROR,
	61
	62	/* Load module not found while attempting to find thread local storage. */
	63	TLS_LOAD_MODULE_NOT_FOUND_ERROR,
	64
	65	/* Thread local storage has not been allocated yet. */
	66	TLS_NOT_ALLOCATED_YET_ERROR,
	67
	68	/* Something else went wrong while attempting to find thread local
71fff37b AC	69	storage. The ``struct gdb_exception'' message field provides
71fff37b AC	70	more detail. */
93ad78a7	71	TLS_GENERIC_ERROR,
fd79ecee DJ	72
	73	/* Problem parsing an XML document. */
	74	XML_PARSE_ERROR,
ccc57cf9 PA	75
	76	/* Error accessing memory. */
	77	MEMORY_ERROR,
93ad78a7	78
973817a3 JB	79	/* Feature is not supported in this copy of GDB. */
	80	UNSUPPORTED_ERROR,
	81
8af8e3bc PA	82	/* Value not available. E.g., a register was not collected in a
	83	traceframe. */
	84	NOT_AVAILABLE_ERROR,
	85
8e3b41a9 JK	86	/* DW_OP_GNU_entry_value resolving failed. */
	87	NO_ENTRY_VALUE_ERROR,
	88
2a78bfb5 AC	89	/* Add more errors here. */
	90	NR_ERRORS
	91	};
	92
71fff37b	93	struct gdb_exception
2a78bfb5 AC	94	{
	95	enum return_reason reason;
	96	enum errors error;
b315da38	97	const char *message;
2a78bfb5 AC	98	};
2a78bfb5 AC	99
c1043fc2	100	/* A pre-defined non-exception. */
71fff37b	101	extern const struct gdb_exception exception_none;
c1043fc2	102
6941d02a AC	103	/* Wrap set/long jmp so that it's more portable (internal to
	104	exceptions). */
	105
	106	#if defined(HAVE_SIGSETJMP)
	107	#define EXCEPTIONS_SIGJMP_BUF sigjmp_buf
	108	#define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1)
	109	#define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val))
	110	#else
	111	#define EXCEPTIONS_SIGJMP_BUF jmp_buf
	112	#define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf)
	113	#define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val))
	114	#endif
	115
	116	/* Functions to drive the exceptions state m/c (internal to
	117	exceptions). */
f9679975	118	EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (volatile struct
3e43a32a	119	gdb_exception *exception,
6941d02a AC	120	return_mask mask);
	121	int exceptions_state_mc_action_iter (void);
	122	int exceptions_state_mc_action_iter_1 (void);
	123
	124	/* Macro to wrap up standard try/catch behavior.
	125
	126	The double loop lets us correctly handle code "break"ing out of the
	127	try catch block. (It works as the "break" only exits the inner
	128	"while" loop, the outer for loop detects this handling it
	129	correctly.) Of course "return" and "goto" are not so lucky.
	130
	131	For instance:
	132
	133	INDENT-OFF
	134
71fff37b	135	volatile struct gdb_exception e;
6941d02a AC	136	TRY_CATCH (e, RETURN_MASK_ERROR)
	137	{
	138	}
	139	switch (e.reason)
	140	{
	141	case RETURN_ERROR: ...
	142	}
	143
	144	*/
	145
	146	#define TRY_CATCH(EXCEPTION,MASK) \
8d19ca47 CV	147	{ \
8d19ca47 CV	148	EXCEPTIONS_SIGJMP_BUF *buf = \
f9679975	149	exceptions_state_mc_init (&(EXCEPTION), (MASK)); \
8d19ca47 CV	150	EXCEPTIONS_SIGSETJMP (*buf); \
	151	} \
	152	while (exceptions_state_mc_action_iter ()) \
	153	while (exceptions_state_mc_action_iter_1 ())
6941d02a AC	154
	155	/* INDENT-ON */
	156
	157
8a076db9	158	/* If E is an exception, print it's error message on the specified
0963b4bd	159	stream. For _fprintf, prefix the message with PREFIX... */
71fff37b AC	160	extern void exception_print (struct ui_file *file, struct gdb_exception e);
71fff37b AC	161	extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
9cbc821d	162	const char *prefix,
a0b31db1	163	...) ATTRIBUTE_PRINTF (3, 4);
8a076db9	164
71fff37b	165	/* Throw an exception (as described by "struct gdb_exception"). Will
2a78bfb5 AC	166	execute a LONG JUMP to the inner most containing exception handler
2a78bfb5 AC	167	established using catch_exceptions() (or similar).
60250e8b AC	168
	169	Code normally throws an exception using error() et.al. For various
	170	reaons, GDB also contains code that throws an exception directly.
	171	For instance, the remote*.c targets contain CNTRL-C signal handlers
	172	that propogate the QUIT event up the exception chain. ``This could
2a78bfb5 AC	173	be a good thing or a dangerous thing.'' -- the Existential
	174	Wombat. */
	175
3e43a32a MS	176	extern void throw_exception (struct gdb_exception exception)
3e43a32a MS	177	ATTRIBUTE_NORETURN;
c25c4a8b JK	178	extern void throw_verror (enum errors, const char *fmt, va_list ap)
	179	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
	180	extern void throw_vfatal (const char *fmt, va_list ap)
	181	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
	182	extern void throw_error (enum errors error, const char *fmt, ...)
	183	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
60250e8b	184
04bd08de TT	185	/* Instead of deprecated_throw_reason, code should use
04bd08de TT	186	throw_exception. */
c25c4a8b JK	187	extern void deprecated_throw_reason (enum return_reason reason)
c25c4a8b JK	188	ATTRIBUTE_NORETURN;
315a522e	189
60250e8b AC	190	/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
	191	handler. If an exception (enum return_reason) is thrown using
	192	throw_exception() than all cleanups installed since
	193	catch_exceptions() was entered are invoked, the (-ve) exception
	194	value is then returned by catch_exceptions. If FUNC() returns
787274f0	195	normally (with a positive or zero return value) then that value is
60250e8b AC	196	returned by catch_exceptions(). It is an internal_error() for
	197	FUNC() to return a negative value.
	198
	199	For the period of the FUNC() call: UIOUT is installed as the output
	200	builder; ERRSTRING is installed as the error/quit message; and a
	201	new cleanup_chain is established. The old values are restored
	202	before catch_exceptions() returns.
	203
	204	The variant catch_exceptions_with_msg() is the same as
	205	catch_exceptions() but adds the ability to return an allocated
	206	copy of the gdb error message. This is used when a silent error is
	207	issued and the caller wants to manually issue the error message.
	208
787274f0 DE	209	MASK specifies what to catch; it is normally set to
	210	RETURN_MASK_ALL, if for no other reason than that the code which
	211	calls catch_errors might not be set up to deal with a quit which
	212	isn't caught. But if the code can deal with it, it generally
	213	should be RETURN_MASK_ERROR, unless for some reason it is more
	214	useful to abort only the portion of the operation inside the
	215	catch_errors. Note that quit should return to the command line
	216	fairly quickly, even if some further processing is being done.
	217
60250e8b AC	218	FIXME; cagney/2001-08-13: The need to override the global UIOUT
	219	builder variable should just go away.
	220
787274f0	221	This function supersedes catch_errors().
60250e8b AC	222
	223	This function uses SETJMP() and LONGJUMP(). */
	224
	225	struct ui_out;
	226	typedef int (catch_exceptions_ftype) (struct ui_out ui_out, void args);
	227	extern int catch_exceptions (struct ui_out *uiout,
	228	catch_exceptions_ftype func, void func_args,
1c3c7ee7	229	return_mask mask);
2a78bfb5	230	typedef void (catch_exception_ftype) (struct ui_out ui_out, void args);
60250e8b AC	231	extern int catch_exceptions_with_msg (struct ui_out *uiout,
	232	catch_exceptions_ftype *func,
	233	void *func_args,
1c3c7ee7	234	char **gdberrmsg,
60250e8b	235	return_mask mask);
8a076db9	236
60250e8b	237	/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
0963b4bd	238	otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
60250e8b	239	probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
0963b4bd	240	value. It's unfortunate that, catch_errors() does not return an
60250e8b AC	241	indication of the exact exception that it caught - quit_flag might
	242	help.
	243
787274f0	244	This function is superseded by catch_exceptions(). */
60250e8b AC	245
	246	typedef int (catch_errors_ftype) (void *);
	247	extern int catch_errors (catch_errors_ftype , void , char *, return_mask);
	248
	249	/* Template to catch_errors() that wraps calls to command
0963b4bd	250	functions. */
60250e8b AC	251
60250e8b AC	252	typedef void (catch_command_errors_ftype) (char *, int);
3e43a32a MS	253	extern int catch_command_errors (catch_command_errors_ftype *func,
3e43a32a MS	254	char *command, int from_tty, return_mask);
60250e8b AC	255
60250e8b AC	256	#endif