| /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
| |
| Copyright (C) 1986-2015 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/>. */ |
| |
| #include "common-defs.h" |
| #include "common-exceptions.h" |
| |
| const struct gdb_exception exception_none = { 0, GDB_NO_ERROR, NULL }; |
| |
| #ifndef __cplusplus |
| |
| /* Possible catcher states. */ |
| enum catcher_state { |
| /* Initial state, a new catcher has just been created. */ |
| CATCHER_CREATED, |
| /* The catch code is running. */ |
| CATCHER_RUNNING, |
| CATCHER_RUNNING_1, |
| /* The catch code threw an exception. */ |
| CATCHER_ABORTING |
| }; |
| |
| /* Possible catcher actions. */ |
| enum catcher_action { |
| CATCH_ITER, |
| CATCH_ITER_1, |
| CATCH_THROWING |
| }; |
| |
| struct catcher |
| { |
| enum catcher_state state; |
| /* Jump buffer pointing back at the exception handler. */ |
| SIGJMP_BUF buf; |
| /* Status buffer belonging to the exception handler. */ |
| struct gdb_exception exception; |
| struct cleanup *saved_cleanup_chain; |
| /* Back link. */ |
| struct catcher *prev; |
| }; |
| |
| /* Where to go for throw_exception(). */ |
| static struct catcher *current_catcher; |
| |
| /* Return length of current_catcher list. */ |
| |
| static int |
| catcher_list_size (void) |
| { |
| int size; |
| struct catcher *catcher; |
| |
| for (size = 0, catcher = current_catcher; |
| catcher != NULL; |
| catcher = catcher->prev) |
| ++size; |
| |
| return size; |
| } |
| |
| SIGJMP_BUF * |
| exceptions_state_mc_init (void) |
| { |
| struct catcher *new_catcher = XCNEW (struct catcher); |
| |
| /* Start with no exception. */ |
| new_catcher->exception = exception_none; |
| |
| /* Prevent error/quit during FUNC from calling cleanups established |
| prior to here. */ |
| new_catcher->saved_cleanup_chain = save_cleanups (); |
| |
| /* Push this new catcher on the top. */ |
| new_catcher->prev = current_catcher; |
| current_catcher = new_catcher; |
| new_catcher->state = CATCHER_CREATED; |
| |
| return &new_catcher->buf; |
| } |
| |
| static void |
| catcher_pop (void) |
| { |
| struct catcher *old_catcher = current_catcher; |
| |
| current_catcher = old_catcher->prev; |
| |
| /* Restore the cleanup chain, the error/quit messages, and the uiout |
| builder, to their original states. */ |
| |
| restore_cleanups (old_catcher->saved_cleanup_chain); |
| |
| xfree (old_catcher); |
| } |
| |
| /* Catcher state machine. Returns non-zero if the m/c should be run |
| again, zero if it should abort. */ |
| |
| static int |
| exceptions_state_mc (enum catcher_action action) |
| { |
| switch (current_catcher->state) |
| { |
| case CATCHER_CREATED: |
| switch (action) |
| { |
| case CATCH_ITER: |
| /* Allow the code to run the catcher. */ |
| current_catcher->state = CATCHER_RUNNING; |
| return 1; |
| default: |
| internal_error (__FILE__, __LINE__, _("bad state")); |
| } |
| case CATCHER_RUNNING: |
| switch (action) |
| { |
| case CATCH_ITER: |
| /* No error/quit has occured. */ |
| return 0; |
| case CATCH_ITER_1: |
| current_catcher->state = CATCHER_RUNNING_1; |
| return 1; |
| case CATCH_THROWING: |
| current_catcher->state = CATCHER_ABORTING; |
| /* See also throw_exception. */ |
| return 1; |
| default: |
| internal_error (__FILE__, __LINE__, _("bad switch")); |
| } |
| case CATCHER_RUNNING_1: |
| switch (action) |
| { |
| case CATCH_ITER: |
| /* The did a "break" from the inner while loop. */ |
| return 0; |
| case CATCH_ITER_1: |
| current_catcher->state = CATCHER_RUNNING; |
| return 0; |
| case CATCH_THROWING: |
| current_catcher->state = CATCHER_ABORTING; |
| /* See also throw_exception. */ |
| return 1; |
| default: |
| internal_error (__FILE__, __LINE__, _("bad switch")); |
| } |
| case CATCHER_ABORTING: |
| switch (action) |
| { |
| case CATCH_ITER: |
| { |
| /* Exit normally if this catcher can handle this |
| exception. The caller analyses the func return |
| values. */ |
| return 0; |
| } |
| default: |
| internal_error (__FILE__, __LINE__, _("bad state")); |
| } |
| default: |
| internal_error (__FILE__, __LINE__, _("bad switch")); |
| } |
| } |
| |
| int |
| exceptions_state_mc_catch (struct gdb_exception *exception, |
| int mask) |
| { |
| *exception = current_catcher->exception; |
| catcher_pop (); |
| |
| if (exception->reason < 0) |
| { |
| if (mask & RETURN_MASK (exception->reason)) |
| { |
| /* Exit normally and let the caller handle the |
| exception. */ |
| return 1; |
| } |
| |
| /* The caller didn't request that the event be caught, relay the |
| event to the next exception_catch/CATCH. */ |
| throw_exception (*exception); |
| } |
| |
| /* No exception was thrown. */ |
| return 0; |
| } |
| |
| int |
| exceptions_state_mc_action_iter (void) |
| { |
| return exceptions_state_mc (CATCH_ITER); |
| } |
| |
| int |
| exceptions_state_mc_action_iter_1 (void) |
| { |
| return exceptions_state_mc (CATCH_ITER_1); |
| } |
| |
| #else /* !__cplusplus */ |
| |
| /* How many nested TRY blocks we have. See exception_messages and |
| throw_it. */ |
| |
| static int try_scope_depth; |
| |
| /* Called on entry to a TRY scope. */ |
| |
| void * |
| exception_try_scope_entry (void) |
| { |
| ++try_scope_depth; |
| return (void *) save_cleanups (); |
| } |
| |
| /* Called on exit of a TRY scope, either normal exit or exception |
| exit. */ |
| |
| void |
| exception_try_scope_exit (void *saved_state) |
| { |
| restore_cleanups ((struct cleanup *) saved_state); |
| --try_scope_depth; |
| } |
| |
| /* Called by the default catch block. IOW, we'll get here before |
| jumping out to the next outermost scope an exception if a GDB |
| exception is not caught. */ |
| |
| void |
| exception_rethrow (void) |
| { |
| /* Run this scope's cleanups before re-throwing to the next |
| outermost scope. */ |
| prepare_to_throw_exception (); |
| do_cleanups (all_cleanups ()); |
| throw; |
| } |
| |
| /* Copy the 'gdb_exception' portion of FROM to TO. */ |
| |
| static void |
| gdb_exception_sliced_copy (struct gdb_exception *to, const struct gdb_exception *from) |
| { |
| *to = *from; |
| } |
| |
| #endif /* !__cplusplus */ |
| |
| /* Return EXCEPTION to the nearest containing catch_errors(). */ |
| |
| void |
| throw_exception (struct gdb_exception exception) |
| { |
| prepare_to_throw_exception (); |
| |
| do_cleanups (all_cleanups ()); |
| |
| #ifndef __cplusplus |
| /* Jump to the containing catch_errors() call, communicating REASON |
| to that call via setjmp's return value. Note that REASON can't |
| be zero, by definition in defs.h. */ |
| exceptions_state_mc (CATCH_THROWING); |
| current_catcher->exception = exception; |
| SIGLONGJMP (current_catcher->buf, exception.reason); |
| #else |
| if (exception.reason == RETURN_QUIT) |
| { |
| gdb_exception_RETURN_MASK_QUIT ex; |
| |
| gdb_exception_sliced_copy (&ex, &exception); |
| throw ex; |
| } |
| else if (exception.reason == RETURN_ERROR) |
| { |
| gdb_exception_RETURN_MASK_ERROR ex; |
| |
| gdb_exception_sliced_copy (&ex, &exception); |
| throw ex; |
| } |
| else |
| gdb_assert_not_reached ("invalid return reason"); |
| #endif |
| } |
| |
| /* A stack of exception messages. |
| This is needed to handle nested calls to throw_it: we don't want to |
| xfree space for a message before it's used. |
| This can happen if we throw an exception during a cleanup: |
| An outer TRY_CATCH may have an exception message it wants to print, |
| but while doing cleanups further calls to throw_it are made. |
| |
| This is indexed by the size of the current_catcher list. |
| It is a dynamically allocated array so that we don't care how deeply |
| GDB nests its TRY_CATCHs. */ |
| static char **exception_messages; |
| |
| /* The number of currently allocated entries in exception_messages. */ |
| static int exception_messages_size; |
| |
| static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0) |
| throw_it (enum return_reason reason, enum errors error, const char *fmt, |
| va_list ap) |
| { |
| struct gdb_exception e; |
| char *new_message; |
| #ifndef __cplusplus |
| int depth = catcher_list_size (); |
| #else |
| int depth = try_scope_depth; |
| #endif |
| |
| gdb_assert (depth > 0); |
| |
| /* Note: The new message may use an old message's text. */ |
| new_message = xstrvprintf (fmt, ap); |
| |
| if (depth > exception_messages_size) |
| { |
| int old_size = exception_messages_size; |
| |
| exception_messages_size = depth + 10; |
| exception_messages = (char **) xrealloc (exception_messages, |
| exception_messages_size |
| * sizeof (char *)); |
| memset (exception_messages + old_size, 0, |
| (exception_messages_size - old_size) * sizeof (char *)); |
| } |
| |
| xfree (exception_messages[depth - 1]); |
| exception_messages[depth - 1] = new_message; |
| |
| /* Create the exception. */ |
| e.reason = reason; |
| e.error = error; |
| e.message = new_message; |
| |
| /* Throw the exception. */ |
| throw_exception (e); |
| } |
| |
| void |
| throw_verror (enum errors error, const char *fmt, va_list ap) |
| { |
| throw_it (RETURN_ERROR, error, fmt, ap); |
| } |
| |
| void |
| throw_vquit (const char *fmt, va_list ap) |
| { |
| throw_it (RETURN_QUIT, GDB_NO_ERROR, fmt, ap); |
| } |
| |
| void |
| throw_error (enum errors error, const char *fmt, ...) |
| { |
| va_list args; |
| |
| va_start (args, fmt); |
| throw_verror (error, fmt, args); |
| va_end (args); |
| } |
| |
| void |
| throw_quit (const char *fmt, ...) |
| { |
| va_list args; |
| |
| va_start (args, fmt); |
| throw_vquit (fmt, args); |
| va_end (args); |
| } |