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Diffstat (limited to 'gdb/common/common-exceptions.c')
| -rw-r--r-- | gdb/common/common-exceptions.c | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/gdb/common/common-exceptions.c b/gdb/common/common-exceptions.c new file mode 100644 index 0000000..c382d86 --- /dev/null +++ b/gdb/common/common-exceptions.c @@ -0,0 +1,308 @@ +/* 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/>. */ + +#include "common-defs.h" +#include "common-exceptions.h" +#include "cleanups.h" + +/* 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. */ + volatile struct gdb_exception *exception; + /* Saved/current state. */ + int mask; + 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 (volatile struct gdb_exception *exception, + return_mask mask) +{ + struct catcher *new_catcher = XCNEW (struct catcher); + + /* Start with no exception, save it's address. */ + exception->reason = 0; + exception->error = GDB_NO_ERROR; + exception->message = NULL; + new_catcher->exception = exception; + + new_catcher->mask = mask; + + /* 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. Just clean up. */ + catcher_pop (); + 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. */ + catcher_pop (); + 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: + { + struct gdb_exception exception = *current_catcher->exception; + + if (current_catcher->mask & RETURN_MASK (exception.reason)) + { + /* Exit normally if this catcher can handle this + exception. The caller analyses the func return + values. */ + catcher_pop (); + return 0; + } + /* The caller didn't request that the event be caught, + relay the event to the next containing + catch_errors(). */ + catcher_pop (); + throw_exception (exception); + } + default: + internal_error (__FILE__, __LINE__, _("bad state")); + } + default: + internal_error (__FILE__, __LINE__, _("bad switch")); + } +} + +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); +} + +/* Return EXCEPTION to the nearest containing catch_errors(). */ + +void +throw_exception (struct gdb_exception exception) +{ + prepare_to_throw_exception (); + + do_cleanups (all_cleanups ()); + + /* 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); +} + +/* 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; + int depth = catcher_list_size (); + + 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); +} |