Remove free-ref, free-set!

* libguile/vm-engine.c (free-ref, free-set!): Remove ops.
* module/language/cps/effects-analysis.scm:
* module/system/vm/assembler.scm:
* module/system/vm/disassembler.scm (code-annotation):
* module/language/cps/compile-bytecode.scm (compile-function): Remove
  support for free-ref / free-set!.

module/language/cps/compile-bytecode.scm

@@ -172,8 +172,6 @@
          (emit-word-ref/immediate asm (from-sp dst) (from-sp (slot obj)) idx))
         (($ $primcall 'pointer-ref/immediate (annotation . idx) (obj))
          (emit-pointer-ref/immediate asm (from-sp dst) (from-sp (slot obj)) idx))
-        (($ $primcall 'free-ref idx (closure))
-         (emit-free-ref asm (from-sp dst) (from-sp (slot closure)) idx))
         (($ $primcall 'char->integer #f (src))
          (emit-char->integer asm (from-sp dst) (from-sp (slot src))))
         (($ $primcall 'integer->char #f (src))
@@ -302,9 +300,6 @@
         (($ $primcall 'pointer-set!/immediate (annotation . idx) (obj val))
          (emit-pointer-set!/immediate asm (from-sp (slot obj)) idx
                                       (from-sp (slot val))))
-        (($ $primcall 'free-set! idx (closure value))
-         (emit-free-set! asm (from-sp (slot closure)) (from-sp (slot value))
-                         idx))
         (($ $primcall 'string-set! #f (string index char))
          (emit-string-set! asm (from-sp (slot string)) (from-sp (slot index))
                            (from-sp (slot char))))

module/language/cps/effects-analysis.scm

@@ -450,11 +450,6 @@ the LABELS that are clobbered by the effects of LABEL."
   ((f32-set! obj bv n x)           (&write-object (annotation->memory-kind param)))
   ((f64-set! obj bv n x)           (&write-object (annotation->memory-kind param))))
 
-;; Closures.
-(define-primitive-effects* param
-  ((free-ref closure)              (&read-field &closure param))
-  ((free-set! closure val)         (&write-field &closure param)))
-
 ;; Modules.
 (define-primitive-effects
   ((current-module)                (&read-object &module))

module/system/vm/assembler.scm

@@ -198,8 +198,6 @@
             emit-bind-kwargs
             emit-bind-rest
             emit-make-closure
-            emit-free-ref
-            emit-free-set!
             emit-current-module
             emit-resolve
             emit-define!

module/system/vm/disassembler.scm

@@ -275,8 +275,6 @@ address of that offset."
      (list "~A" (builtin-index->name idx)))
     (((or 'static-ref 'static-set!) _ target)
      (list "~@Y" (dereference-scm target)))
-    (((or 'free-ref 'free-set!) _ _ index)
-     (list "free var ~a" index))
     (('resolve-module dst name public)
      (list "~a" (if (zero? public) "private" "public")))
     (('toplevel-box _ var-offset mod-offset sym-offset bound?)