1 files changed, 33 insertions, 19 deletions

diff --git a/src/bytecode.c b/src/bytecode.c
index ad2f7d18ade..b2e9e3c5b56 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -51,7 +51,7 @@ by Hallvard:
  *
  * define BYTE_CODE_METER to enable generation of a byte-op usage histogram.
  */
-/* #define BYTE_CODE_SAFE */
+#define BYTE_CODE_SAFE
 /* #define BYTE_CODE_METER */
 
 
@@ -88,7 +88,7 @@ extern Lisp_Object Qand_optional, Qand_rest;
 
 /*  Byte codes: */
 
-#define Bstack_ref 0
+#define Bstack_ref 0 /* Actually, Bstack_ref+0 is not implemented: use dup.  */
 #define Bvarref 010
 #define Bvarset 020
 #define Bvarbind 030
@@ -189,8 +189,8 @@ extern Lisp_Object Qand_optional, Qand_rest;
 
 #define Bunwind_protect 0216
 #define Bcondition_case 0217
-#define Btemp_output_buffer_setup 0220
-#define Btemp_output_buffer_show 0221
+#define Btemp_output_buffer_setup 0220 /* Obsolete.  */
+#define Btemp_output_buffer_show 0221  /* Obsolete.  */
 
 #define Bunbind_all 0222        /* Obsolete.  */
 
@@ -898,9 +898,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
 
         case Bsave_window_excursion: /* Obsolete.  */
           {
-            register Lisp_Object val;
             register int count = SPECPDL_INDEX ();
-
             record_unwind_protect (Fset_window_configuration,
                                    Fcurrent_window_configuration (Qnil));
             BEFORE_POTENTIAL_GC ();
@@ -940,7 +938,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
             break;
           }
 
-        case Btemp_output_buffer_setup:
+        case Btemp_output_buffer_setup: /* Obsolete.  */
           BEFORE_POTENTIAL_GC ();
           CHECK_STRING (TOP);
           temp_output_buffer_setup (SSDATA (TOP));
@@ -948,7 +946,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
           TOP = Vstandard_output;
           break;
 
-        case Btemp_output_buffer_show:
+        case Btemp_output_buffer_show: /* Obsolete.  */
           {
             Lisp_Object v1;
             BEFORE_POTENTIAL_GC ();
@@ -1710,26 +1708,42 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
 #endif
 
           /* Handy byte-codes for lexical binding.  */
-        case Bstack_ref:
+          /* case Bstack_ref: */  /* Use `dup' instead.  */
         case Bstack_ref+1:
         case Bstack_ref+2:
         case Bstack_ref+3:
         case Bstack_ref+4:
         case Bstack_ref+5:
-          PUSH (stack.bottom[op - Bstack_ref]);
-          break;
+          {
+            Lisp_Object *ptr = top - (op - Bstack_ref);
+            PUSH (*ptr);
+            break;
+          }
         case Bstack_ref+6:
-          PUSH (stack.bottom[FETCH]);
-          break;
+          {
+            Lisp_Object *ptr = top - (FETCH);
+            PUSH (*ptr);
+            break;
+          }
         case Bstack_ref+7:
-          PUSH (stack.bottom[FETCH2]);
-          break;
+          {
+            Lisp_Object *ptr = top - (FETCH2);
+            PUSH (*ptr);
+            break;
+          }
+          /* stack-set-0 = discard; stack-set-1 = discard-1-preserve-tos.  */
         case Bstack_set:
-          stack.bottom[FETCH] = POP;
-          break;
+          {
+            Lisp_Object *ptr = top - (FETCH);
+            *ptr = POP;
+            break;
+          }
         case Bstack_set2:
-          stack.bottom[FETCH2] = POP;
-          break;
+          {
+            Lisp_Object *ptr = top - (FETCH2);
+            *ptr = POP;
+            break;
+          }
         case BdiscardN:
           op = FETCH;
           if (op & 0x80)