Remove interpreter’s byte stack

This improves performance overall on my benchmark on x86-64,
since the interpreted program-counter resides in a machine
register rather than in RAM.
* etc/DEBUG, src/.gdbinit: Remove xbytecode GDB command, as there
is no longer a byte stack to decode.
* src/bytecode.c (struct byte_stack, byte_stack_list)
(relocate_byte_stack): Remove.  All uses removed.
(FETCH): Simplify now that pc is now local (typically, in a
register) and no longer needs to be relocated.
(CHECK_RANGE): Remove.  All uses now done inline, in a different way.
(BYTE_CODE_QUIT): Remove; now done by op_relative_branch.
(exec_byte_code): Allocate a copy of the function’s bytecode,
so that there is no problem if GC moves it.
* src/lisp.h (struct handler): Remove byte_stack member.
All uses removed.
* src/thread.c (unmark_threads): Remove.  All uses removed.
* src/thread.h (struct thread_state): Remove m_byte_stack_list member.
All uses removed.  m_stack_bottom is now the first non-Lisp field.

1 files changed, 1 insertions, 9 deletions

diff --git a/src/thread.h b/src/thread.h
index 33f8ea70636..b8524014ea4 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -56,14 +56,7 @@ struct thread_state
      waiting on.  */
   Lisp_Object event_object;
 
-  /* m_byte_stack_list must be the first non-lisp field.  */
-  /* A list of currently active byte-code execution value stacks.
-     Fbyte_code adds an entry to the head of this list before it starts
-     processing byte-code, and it removed the entry again when it is
-     done.  Signaling an error truncates the list.  */
-  struct byte_stack *m_byte_stack_list;
-#define byte_stack_list (current_thread->m_byte_stack_list)
-
+  /* m_stack_bottom must be the first non-Lisp field.  */
   /* An address near the bottom of the stack.
      Tells GC how to save a copy of the stack.  */
   char *m_stack_bottom;
@@ -227,7 +220,6 @@ struct Lisp_CondVar
 
 extern struct thread_state *current_thread;
 
-extern void unmark_threads (void);
 extern void finalize_one_thread (struct thread_state *state);
 extern void finalize_one_mutex (struct Lisp_Mutex *);
 extern void finalize_one_condvar (struct Lisp_CondVar *);