Simplify exception handling

Now that cleanups have been removed, TRY/CATCH can't be SJLJ-based any
more.  This patch simplifies the exception handling code, by removing
the non-working variants.

Note that the "pure" C++ exception handling code is removed as well; I
think the route forward must be to change exceptions to be
self-destructing, so that try_scope_depth can simply be removed.

Some longjmp-based code remains, as it is needed to throw an exception
through readline.

gdb/ChangeLog
2019-04-08  Tom Tromey  <tom@tromey.com>

	* common/common-exceptions.h (GDB_XCPT_SJMP, GDB_XCPT_TRY)
	(GDB_XCPT_RAW_TRY, GDB_XCPT): Remove.
	(TRY, CATCH, END_CATCH): Remove some definitions.
	* common/common-exceptions.c: Don't use GDB_XCPT.
	(catcher_list_size): Remove.
	(throw_exception, throw_it): Simplify.

1 files changed, 0 insertions, 36 deletions

diff --git a/gdb/common/common-exceptions.c b/gdb/common/common-exceptions.c
index 4e67e89..c3529c9 100644
--- a/gdb/common/common-exceptions.c
+++ b/gdb/common/common-exceptions.c
@@ -54,26 +54,6 @@ struct catcher
 /* Where to go for throw_exception().  */
 static struct catcher *current_catcher;
 
-#if GDB_XCPT == GDB_XCPT_SJMP
-
-/* 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;
-}
-
-#endif
-
 jmp_buf *
 exceptions_state_mc_init (void)
 {
@@ -205,8 +185,6 @@ exceptions_state_mc_action_iter_1 (void)
   return exceptions_state_mc (CATCH_ITER_1);
 }
 
-#if GDB_XCPT != GDB_XCPT_SJMP
-
 /* How many nested TRY blocks we have.  See exception_messages and
    throw_it.  */
 
@@ -248,8 +226,6 @@ gdb_exception_sliced_copy (struct gdb_exception *to, const struct gdb_exception
   *to = *from;
 }
 
-#endif /* !GDB_XCPT_SJMP */
-
 /* Return EXCEPTION to the nearest containing CATCH_SJLJ block.  */
 
 void
@@ -263,8 +239,6 @@ throw_exception_sjlj (struct gdb_exception exception)
   longjmp (current_catcher->buf, exception.reason);
 }
 
-#if GDB_XCPT != GDB_XCPT_SJMP
-
 /* Implementation of throw_exception that uses C++ try/catch.  */
 
 static ATTRIBUTE_NORETURN void
@@ -288,16 +262,10 @@ throw_exception_cxx (struct gdb_exception exception)
     gdb_assert_not_reached ("invalid return reason");
 }
 
-#endif
-
 void
 throw_exception (struct gdb_exception exception)
 {
-#if GDB_XCPT == GDB_XCPT_SJMP
-  throw_exception_sjlj (exception);
-#else
   throw_exception_cxx (exception);
-#endif
 }
 
 /* A stack of exception messages.
@@ -321,11 +289,7 @@ throw_it (enum return_reason reason, enum errors error, const char *fmt,
 {
   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);