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/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
Copyright (C) 1986-2014 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))
typedef enum
{
RETURN_MASK_QUIT = RETURN_MASK (RETURN_QUIT),
RETURN_MASK_ERROR = RETURN_MASK (RETURN_ERROR),
RETURN_MASK_ALL = (RETURN_MASK_QUIT | RETURN_MASK_ERROR)
} 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,
/* Value not available. E.g., a register was not collected in a
traceframe. */
NOT_AVAILABLE_ERROR,
/* Value was optimized out. Note: if the value was a register, this
means the register was not saved in the frame. */
OPTIMIZED_OUT_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,
/* An undefined command was executed. */
UNDEFINED_COMMAND_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);
/* 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);
/* Like catch_command_errors, but works with const command and args. */
typedef void (catch_command_errors_const_ftype) (const char *, int);
extern int catch_command_errors_const (catch_command_errors_const_ftype *func,
const char *arg, int from_tty, return_mask);
#endif
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