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

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

   Copyright (C) 1986-2013 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,

  /* Target throwing an error has been closed.  Current command should be
     aborted as the inferior state is no longer valid.  */
  TARGET_CLOSE_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 *arg, int from_tty, return_mask);

#endif
Commit	Line	Data
60250e8b AC	1	/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
60250e8b AC	2
28e7fd62	3	Copyright (C) 1986-2013 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
598d3636 JK	89	/* Target throwing an error has been closed. Current command should be
	90	aborted as the inferior state is no longer valid. */
	91	TARGET_CLOSE_ERROR,
	92
2a78bfb5 AC	93	/* Add more errors here. */
	94	NR_ERRORS
	95	};
	96
71fff37b	97	struct gdb_exception
2a78bfb5 AC	98	{
	99	enum return_reason reason;
	100	enum errors error;
b315da38	101	const char *message;
2a78bfb5 AC	102	};
2a78bfb5 AC	103
c1043fc2	104	/* A pre-defined non-exception. */
71fff37b	105	extern const struct gdb_exception exception_none;
c1043fc2	106
6941d02a AC	107	/* Wrap set/long jmp so that it's more portable (internal to
	108	exceptions). */
	109
	110	#if defined(HAVE_SIGSETJMP)
	111	#define EXCEPTIONS_SIGJMP_BUF sigjmp_buf
	112	#define EXCEPTIONS_SIGSETJMP(buf) sigsetjmp((buf), 1)
	113	#define EXCEPTIONS_SIGLONGJMP(buf,val) siglongjmp((buf), (val))
	114	#else
	115	#define EXCEPTIONS_SIGJMP_BUF jmp_buf
	116	#define EXCEPTIONS_SIGSETJMP(buf) setjmp(buf)
	117	#define EXCEPTIONS_SIGLONGJMP(buf,val) longjmp((buf), (val))
	118	#endif
	119
	120	/* Functions to drive the exceptions state m/c (internal to
	121	exceptions). */
f9679975	122	EXCEPTIONS_SIGJMP_BUF *exceptions_state_mc_init (volatile struct
3e43a32a	123	gdb_exception *exception,
6941d02a AC	124	return_mask mask);
	125	int exceptions_state_mc_action_iter (void);
	126	int exceptions_state_mc_action_iter_1 (void);
	127
	128	/* Macro to wrap up standard try/catch behavior.
	129
	130	The double loop lets us correctly handle code "break"ing out of the
	131	try catch block. (It works as the "break" only exits the inner
	132	"while" loop, the outer for loop detects this handling it
	133	correctly.) Of course "return" and "goto" are not so lucky.
	134
	135	For instance:
	136
	137	INDENT-OFF
	138
71fff37b	139	volatile struct gdb_exception e;
6941d02a AC	140	TRY_CATCH (e, RETURN_MASK_ERROR)
	141	{
	142	}
	143	switch (e.reason)
	144	{
	145	case RETURN_ERROR: ...
	146	}
	147
	148	*/
	149
	150	#define TRY_CATCH(EXCEPTION,MASK) \
8d19ca47 CV	151	{ \
8d19ca47 CV	152	EXCEPTIONS_SIGJMP_BUF *buf = \
f9679975	153	exceptions_state_mc_init (&(EXCEPTION), (MASK)); \
8d19ca47 CV	154	EXCEPTIONS_SIGSETJMP (*buf); \
	155	} \
	156	while (exceptions_state_mc_action_iter ()) \
	157	while (exceptions_state_mc_action_iter_1 ())
6941d02a AC	158
	159	/* INDENT-ON */
	160
	161
8a076db9	162	/* If E is an exception, print it's error message on the specified
0963b4bd	163	stream. For _fprintf, prefix the message with PREFIX... */
71fff37b AC	164	extern void exception_print (struct ui_file *file, struct gdb_exception e);
71fff37b AC	165	extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
9cbc821d	166	const char *prefix,
a0b31db1	167	...) ATTRIBUTE_PRINTF (3, 4);
8a076db9	168
71fff37b	169	/* Throw an exception (as described by "struct gdb_exception"). Will
2a78bfb5 AC	170	execute a LONG JUMP to the inner most containing exception handler
2a78bfb5 AC	171	established using catch_exceptions() (or similar).
60250e8b AC	172
	173	Code normally throws an exception using error() et.al. For various
	174	reaons, GDB also contains code that throws an exception directly.
	175	For instance, the remote*.c targets contain CNTRL-C signal handlers
	176	that propogate the QUIT event up the exception chain. ``This could
2a78bfb5 AC	177	be a good thing or a dangerous thing.'' -- the Existential
	178	Wombat. */
	179
3e43a32a MS	180	extern void throw_exception (struct gdb_exception exception)
3e43a32a MS	181	ATTRIBUTE_NORETURN;
c25c4a8b JK	182	extern void throw_verror (enum errors, const char *fmt, va_list ap)
	183	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
	184	extern void throw_vfatal (const char *fmt, va_list ap)
	185	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
	186	extern void throw_error (enum errors error, const char *fmt, ...)
	187	ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
60250e8b	188
04bd08de TT	189	/* Instead of deprecated_throw_reason, code should use
04bd08de TT	190	throw_exception. */
c25c4a8b JK	191	extern void deprecated_throw_reason (enum return_reason reason)
c25c4a8b JK	192	ATTRIBUTE_NORETURN;
315a522e	193
60250e8b AC	194	/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
	195	handler. If an exception (enum return_reason) is thrown using
	196	throw_exception() than all cleanups installed since
	197	catch_exceptions() was entered are invoked, the (-ve) exception
	198	value is then returned by catch_exceptions. If FUNC() returns
787274f0	199	normally (with a positive or zero return value) then that value is
60250e8b AC	200	returned by catch_exceptions(). It is an internal_error() for
	201	FUNC() to return a negative value.
	202
	203	For the period of the FUNC() call: UIOUT is installed as the output
	204	builder; ERRSTRING is installed as the error/quit message; and a
	205	new cleanup_chain is established. The old values are restored
	206	before catch_exceptions() returns.
	207
	208	The variant catch_exceptions_with_msg() is the same as
	209	catch_exceptions() but adds the ability to return an allocated
	210	copy of the gdb error message. This is used when a silent error is
	211	issued and the caller wants to manually issue the error message.
	212
787274f0 DE	213	MASK specifies what to catch; it is normally set to
	214	RETURN_MASK_ALL, if for no other reason than that the code which
	215	calls catch_errors might not be set up to deal with a quit which
	216	isn't caught. But if the code can deal with it, it generally
	217	should be RETURN_MASK_ERROR, unless for some reason it is more
	218	useful to abort only the portion of the operation inside the
	219	catch_errors. Note that quit should return to the command line
	220	fairly quickly, even if some further processing is being done.
	221
60250e8b AC	222	FIXME; cagney/2001-08-13: The need to override the global UIOUT
	223	builder variable should just go away.
	224
787274f0	225	This function supersedes catch_errors().
60250e8b AC	226
	227	This function uses SETJMP() and LONGJUMP(). */
	228
	229	struct ui_out;
	230	typedef int (catch_exceptions_ftype) (struct ui_out ui_out, void args);
	231	extern int catch_exceptions (struct ui_out *uiout,
	232	catch_exceptions_ftype func, void func_args,
1c3c7ee7	233	return_mask mask);
2a78bfb5	234	typedef void (catch_exception_ftype) (struct ui_out ui_out, void args);
60250e8b AC	235	extern int catch_exceptions_with_msg (struct ui_out *uiout,
	236	catch_exceptions_ftype *func,
	237	void *func_args,
1c3c7ee7	238	char **gdberrmsg,
60250e8b	239	return_mask mask);
8a076db9	240
60250e8b	241	/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
0963b4bd	242	otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
60250e8b	243	probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
0963b4bd	244	value. It's unfortunate that, catch_errors() does not return an
60250e8b AC	245	indication of the exact exception that it caught - quit_flag might
	246	help.
	247
787274f0	248	This function is superseded by catch_exceptions(). */
60250e8b AC	249
	250	typedef int (catch_errors_ftype) (void *);
	251	extern int catch_errors (catch_errors_ftype , void , char *, return_mask);
	252
	253	/* Template to catch_errors() that wraps calls to command
0963b4bd	254	functions. */
60250e8b AC	255
60250e8b AC	256	typedef void (catch_command_errors_ftype) (char *, int);
3e43a32a	257	extern int catch_command_errors (catch_command_errors_ftype *func,
97f8dd09	258	char *arg, int from_tty, return_mask);
60250e8b AC	259
60250e8b AC	260	#endif