diff options
Diffstat (limited to 'gdbsupport/common-exceptions.c')
| -rw-r--r-- | gdbsupport/common-exceptions.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/gdbsupport/common-exceptions.c b/gdbsupport/common-exceptions.c new file mode 100644 index 00000000000..0cc515ba792 --- /dev/null +++ b/gdbsupport/common-exceptions.c @@ -0,0 +1,235 @@ +/* Exception (throw catch) mechanism, for GDB, the GNU debugger. + + Copyright (C) 1986-2020 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 <forward_list> + +/* 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 = CATCHER_CREATED; + /* Jump buffer pointing back at the exception handler. */ + jmp_buf buf; + /* Status buffer belonging to the exception handler. */ + struct gdb_exception exception; +}; + +/* Where to go for throw_exception(). */ +static std::forward_list<struct catcher> catchers; + +jmp_buf * +exceptions_state_mc_init () +{ + catchers.emplace_front (); + return &catchers.front ().buf; +} + +/* 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 (catchers.front ().state) + { + case CATCHER_CREATED: + switch (action) + { + case CATCH_ITER: + /* Allow the code to run the catcher. */ + catchers.front ().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: + catchers.front ().state = CATCHER_RUNNING_1; + return 1; + case CATCH_THROWING: + catchers.front ().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: + catchers.front ().state = CATCHER_RUNNING; + return 0; + case CATCH_THROWING: + catchers.front ().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 = std::move (catchers.front ().exception); + catchers.pop_front (); + + 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_SJLJ. */ + throw_exception_sjlj (*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); +} + +/* Return EXCEPTION to the nearest containing CATCH_SJLJ block. */ + +void +throw_exception_sjlj (const struct gdb_exception &exception) +{ + /* Jump to the nearest CATCH_SJLJ block, communicating REASON to + that call via setjmp's return value. Note that REASON can't be + zero, by definition in common-exceptions.h. */ + exceptions_state_mc (CATCH_THROWING); + enum return_reason reason = exception.reason; + catchers.front ().exception = exception; + longjmp (catchers.front ().buf, reason); +} + +/* Implementation of throw_exception that uses C++ try/catch. */ + +void +throw_exception (gdb_exception &&exception) +{ + if (exception.reason == RETURN_QUIT) + throw gdb_exception_quit (std::move (exception)); + else if (exception.reason == RETURN_ERROR) + throw gdb_exception_error (std::move (exception)); + else + gdb_assert_not_reached ("invalid return reason"); +} + +static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0) +throw_it (enum return_reason reason, enum errors error, const char *fmt, + va_list ap) +{ + if (reason == RETURN_QUIT) + throw gdb_exception_quit (fmt, ap); + else if (reason == RETURN_ERROR) + throw gdb_exception_error (error, fmt, ap); + else + gdb_assert_not_reached ("invalid return reason"); +} + +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); +} |