/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
- Copyright (C) 1986-2016 Free Software Foundation, Inc.
+ Copyright (C) 1986-2019 Free Software Foundation, Inc.
This file is part of GDB.
#include "common-defs.h"
#include "common-exceptions.h"
-
-const struct gdb_exception exception_none = { (enum return_reason) 0, GDB_NO_ERROR, NULL };
-
-#if GDB_XCPT == GDB_XCPT_SJMP
+#include <forward_list>
/* Possible catcher states. */
enum catcher_state {
struct catcher
{
- enum catcher_state state;
+ enum catcher_state state = CATCHER_CREATED;
/* Jump buffer pointing back at the exception handler. */
- SIGJMP_BUF buf;
+ jmp_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;
-}
+static std::forward_list<struct catcher> catchers;
-SIGJMP_BUF *
-exceptions_state_mc_init (void)
+jmp_buf *
+exceptions_state_mc_init ()
{
- 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);
+ catchers.emplace_front ();
+ return &catchers.front ().buf;
}
/* Catcher state machine. Returns non-zero if the m/c should be run
static int
exceptions_state_mc (enum catcher_action action)
{
- switch (current_catcher->state)
+ switch (catchers.front ().state)
{
case CATCHER_CREATED:
switch (action)
{
case CATCH_ITER:
/* Allow the code to run the catcher. */
- current_catcher->state = CATCHER_RUNNING;
+ catchers.front ().state = CATCHER_RUNNING;
return 1;
default:
internal_error (__FILE__, __LINE__, _("bad state"));
/* No error/quit has occured. */
return 0;
case CATCH_ITER_1:
- current_catcher->state = CATCHER_RUNNING_1;
+ catchers.front ().state = CATCHER_RUNNING_1;
return 1;
case CATCH_THROWING:
- current_catcher->state = CATCHER_ABORTING;
+ catchers.front ().state = CATCHER_ABORTING;
/* See also throw_exception. */
return 1;
default:
/* The did a "break" from the inner while loop. */
return 0;
case CATCH_ITER_1:
- current_catcher->state = CATCHER_RUNNING;
+ catchers.front ().state = CATCHER_RUNNING;
return 0;
case CATCH_THROWING:
- current_catcher->state = CATCHER_ABORTING;
+ catchers.front ().state = CATCHER_ABORTING;
/* See also throw_exception. */
return 1;
default:
exceptions_state_mc_catch (struct gdb_exception *exception,
int mask)
{
- *exception = current_catcher->exception;
- catcher_pop ();
+ *exception = std::move (catchers.front ().exception);
+ catchers.pop_front ();
if (exception->reason < 0)
{
}
/* The caller didn't request that the event be caught, relay the
- event to the next exception_catch/CATCH. */
- throw_exception (*exception);
+ event to the next exception_catch/CATCH_SJLJ. */
+ throw_exception_sjlj (*exception);
}
/* No exception was thrown. */
return exceptions_state_mc (CATCH_ITER_1);
}
-#else /* !GDB_XCPT_SJMP */
-
-/* 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. */
+/* Return EXCEPTION to the nearest containing CATCH_SJLJ block. */
void
-exception_try_scope_exit (void *saved_state)
+throw_exception_sjlj (const struct gdb_exception &exception)
{
- 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;
+ /* 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);
}
-#endif /* !GDB_XCPT_SJMP */
-
-/* Return EXCEPTION to the nearest containing catch_errors(). */
+/* Implementation of throw_exception that uses C++ try/catch. */
void
-throw_exception (struct gdb_exception exception)
+throw_exception (gdb_exception &&exception)
{
- prepare_to_throw_exception ();
-
- do_cleanups (all_cleanups ());
-
-#if GDB_XCPT == GDB_XCPT_SJMP
- /* 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;
- }
+ throw gdb_exception_quit (std::move (exception));
else if (exception.reason == RETURN_ERROR)
- {
- gdb_exception_RETURN_MASK_ERROR ex;
-
- gdb_exception_sliced_copy (&ex, &exception);
- throw ex;
- }
+ throw gdb_exception_error (std::move (exception));
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;
-#if GDB_XCPT == GDB_XCPT_SJMP
- 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 = XRESIZEVEC (char *, exception_messages,
- exception_messages_size);
- 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);
+ 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
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