Introduce new bytecodes for efficient catch/condition-case in lexbind.

* lisp/emacs-lisp/byte-opt.el (byte-optimize-form-code-walker):
Optimize under `condition-case' and `catch' if
byte-compile--use-old-handlers is nil.
(disassemble-offset): Handle new bytecodes.

* lisp/emacs-lisp/bytecomp.el (byte-pushcatch, byte-pushconditioncase)
(byte-pophandler): New byte codes.
(byte-goto-ops): Adjust accordingly.
(byte-compile--use-old-handlers): New var.
(byte-compile-catch): Use new byte codes depending on
byte-compile--use-old-handlers.
(byte-compile-condition-case--old): Rename from
byte-compile-condition-case.
(byte-compile-condition-case--new): New function.
(byte-compile-condition-case): New function that dispatches depending
on byte-compile--use-old-handlers.
(byte-compile-unwind-protect): Pass a function to byte-unwind-protect
when we can.

* lisp/emacs-lisp/cconv.el (cconv-convert, cconv-analyse-form): Adjust for
the new compilation scheme using the new byte-codes.

* src/alloc.c (Fgarbage_collect): Merge scans of handlerlist and catchlist,
and make them unconditional now that they're heap-allocated.

* src/bytecode.c (BYTE_CODES): Add Bpushcatch, Bpushconditioncase
and Bpophandler.
(bcall0): New function.
(exec_byte_code): Add corresponding cases.  Improve error message when
encountering an invalid byte-code.  Let Bunwind_protect accept
a function (rather than a list of expressions) as argument.

* src/eval.c (catchlist): Remove (merge with handlerlist).
(handlerlist, lisp_eval_depth): Not static any more.
(internal_catch, internal_condition_case, internal_condition_case_1)
(internal_condition_case_2, internal_condition_case_n):
Use PUSH_HANDLER.
(unwind_to_catch, Fthrow, Fsignal): Adjust to merged
handlerlist/catchlist.
(internal_lisp_condition_case): Use PUSH_HANDLER.  Adjust to new
handlerlist which can only handle a single condition-case handler at
a time.
(find_handler_clause): Simplify since we only a single branch here
any more.

* src/lisp.h (struct handler): Merge struct handler and struct catchtag.
(PUSH_HANDLER): New macro.
(catchlist): Remove.
(handlerlist): Always declare.

1 files changed, 6 insertions, 14 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 2d9828ffa79..6b07f0bd7b1 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -5370,23 +5370,15 @@ See Info node `(elisp)Garbage Collection'.  */)
         mark_object (tail->var[i]);
   }
   mark_byte_stack ();
+#endif
   {
-    struct catchtag *catch;
     struct handler *handler;
-
-  for (catch = catchlist; catch; catch = catch->next)
-    {
-      mark_object (catch->tag);
-      mark_object (catch->val);
-    }
-  for (handler = handlerlist; handler; handler = handler->next)
-    {
-      mark_object (handler->handler);
-      mark_object (handler->var);
-    }
+    for (handler = handlerlist; handler; handler = handler->next)
+      {
+        mark_object (handler->tag_or_ch);
+        mark_object (handler->val);
+      }
   }
-#endif
-
 #ifdef HAVE_WINDOW_SYSTEM
   mark_fringe_data ();
 #endif