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(in-package "ACL2")
(include-book "bcv-model")
;; (defun max-stack (sig-frame)
;; (g 'max-stack sig-frame))
(defun bcv-simple-check-PUSH (inst sig-frame)
(declare (ignore inst))
(<= (+ 1 (g 'op-stack sig-frame))
(max-stack sig-frame)))
;; (defun advance-pc (sig-frame)
;; (s 'pc
;; (+ 1 (g 'pc sig-frame))
;; sig-frame))
;; (defun sig-frame-push-value (v sig-frame)
;; (declare (ignore v))
;; (s 'op-stack
;; (+ 1 (g 'op-stack sig-frame))
;; sig-frame))
(defun bcv-simple-execute-PUSH (inst sig-frame)
(list
(advance-pc
(sig-frame-push-value (arg inst)
sig-frame))))
(defun bcv-simple-check-POP (inst sig-frame)
(declare (ignore inst))
(<= 1 (g 'op-stack sig-frame)))
;; (defun sig-frame-pop-value (sig-frame)
;; (if (zp (g 'op-stack sig-frame))
;; sig-frame
;; (s 'op-stack
;; (- (g 'op-stack sig-frame) 1)
;; sig-frame)))
(defun bcv-simple-execute-POP (inst sig-frame)
(declare (ignore inst))
(list (advance-pc
(sig-frame-pop-value sig-frame))))
;;; The only important thing we care (in this example) is the size of the
;;; operand stack.
;;;
;;; Our BCV examine a program, method by method.
;;;
;;; We will show that verified program will never violate the operand stack
;;; size limit.
(defun bcv-simple-check-IFEQ (inst sig-frame)
(declare (ignore inst))
(<= 1 (g 'op-stack sig-frame)))
(defun bcv-simple-execute-IFEQ (inst sig-frame)
(list
(advance-pc (sig-frame-pop-value sig-frame))
(s 'pc (arg inst)
(sig-frame-pop-value sig-frame))))
;; note IFEQ has two possible return state!
;; (defun bcv-simple-check-INVOKE (inst sig-frame)
;; (let* ((method-name (arg inst))
;; (method-table (g 'method-table sig-frame))
;; (method (binding method-name method-table))
;; (nargs (g 'nargs method)))
;; (and (bound? method-name method-table)
;; (<= 0 (g 'max-stack (binding method-name method-table)))
;; (equal (g 'method-table
;; (cdr (assoc-equal 0 (g 'sig-vector (binding method-name
;; method-table)))))
;; method-table)
;; ;;;
;; ;;; note: this is WRONG!!!
;; ;;; because nothing will satisfy it!!!
;; ;;; Fri Nov 11 11:49:29 2005
;; ;;;
;; (equal (g 'op-stack
;; (cdr (assoc-equal 0 (g 'sig-vector (binding method-name
;; method-table)))))
;; 0)
;; (equal (g 'method-name (binding method-name
;; method-table))
;; method-name)
;; ;; we need these above three to assert that next state
;; ;; is compatible with
;; (integerp nargs)
;; (<= 0 nargs)
;; (<= nargs (g 'op-stack sig-frame))
;; (<= (+ 1 (- (g 'op-stack sig-frame)
;; nargs))
;; (max-stack sig-frame)))))
(defun bcv-simple-check-INVOKE (inst sig-frame)
(let* ((method-name (arg inst)) ;; ctx maps
(method-table (g 'method-table sig-frame)) ;; the value into the frames of sig-vector
(method (binding method-name method-table))
(nargs (g 'nargs method)))
(and (bound? method-name method-table)
(<= 0 (g 'max-stack (binding method-name method-table)))
;; (equal (g 'method-table
;; (cdr (assoc-equal 0 (g 'sig-vector (binding method-name
;; method-table)))))
;; method-table) ;; add one level redirect! Fri Nov 11 12:03:50 2005
;; (equal (g 'op-stack
;; (cdr (assoc-equal 0 (g 'sig-vector (binding method-name
;; method-table)))))
;; 0)
;; (equal (g 'method-name (binding method-name
;; method-table))
;; method-name)
;; we need these above three to assert that next state
;; is compatible with
(integerp nargs)
(<= 0 nargs)
(<= nargs (g 'op-stack sig-frame))
(<= (+ 1 (- (g 'op-stack sig-frame)
nargs))
(max-stack sig-frame)))))
;;; Note:
;;; make sure it has enough space for arguments
;;; make sure the return value will not overflow the stack!!
;;;
;;; values are always of size 1!! (in JVM it could be size two)
(defun bcv-simple-check-HALT (inst sig-frame)
(declare (ignore inst sig-frame))
t)
(defun bcv-simple-execute-HALT (inst sig-frame)
(declare (ignore inst sig-frame))
nil)
(defun bcv-simple-check-RETURN (inst sig-frame)
(declare (ignore inst))
(<= 1 (g 'op-stack sig-frame)))
(defun bcv-simple-execute-RETURN (inst sig-frame)
(declare (ignore inst sig-frame))
nil)
(defun bcv-simple-check-step-pre (inst sig-frame)
(let* ((opcode (op-code inst)))
(cond ((equal opcode 'INVOKE)
(bcv-simple-check-INVOKE inst sig-frame))
((equal opcode 'PUSH)
(bcv-simple-check-PUSH inst sig-frame))
((equal opcode 'IFEQ)
(bcv-simple-check-IFEQ inst sig-frame))
((equal opcode 'HALT)
(bcv-simple-check-HALT inst sig-frame))
((equal opcode 'POP)
(bcv-simple-check-POP inst sig-frame))
((equal opcode 'RETURN)
(bcv-simple-check-RETURN inst sig-frame))
(t nil))))
;; (defun sig-frame-pop-n (n sig-frame)
;; (if (zp n)
;; sig-frame
;; (sig-frame-pop-n (- n 1)
;; (sig-frame-pop-value sig-frame))))
(defun bcv-simple-execute-INVOKE (inst sig-frame)
(let* ((method-name (arg inst))
(method-table (g 'method-table sig-frame))
(method (binding method-name method-table))
(nargs (g 'nargs method))
(ret (g 'ret method)))
(list
(advance-pc
(sig-frame-push-value ret
(sig-frame-pop-n nargs sig-frame))))))
(defun bcv-simple-execute-step (inst sig-frame)
(let* ((opcode (op-code inst)))
(cond ((equal opcode 'INVOKE)
(bcv-simple-execute-INVOKE inst sig-frame))
((equal opcode 'PUSH)
(bcv-simple-execute-PUSH inst sig-frame))
((equal opcode 'IFEQ)
(bcv-simple-execute-IFEQ inst sig-frame))
((equal opcode 'HALT)
(bcv-simple-execute-HALT inst sig-frame))
((equal opcode 'POP)
(bcv-simple-execute-POP inst sig-frame))
((equal opcode 'RETURN)
(bcv-simple-execute-RETURN inst sig-frame))
(t nil))))
;; (defun sig-local-compatible (slocals glocals)
;; (declare (ignore slocals glocals))
;; ;; temp implementation
;; t)
;; (defun sig-opstack-compatible (sframe gframe)
;; (equal (g 'op-stack sframe)
;; (g 'op-stack gframe)))
;; (defun sig-frame-compatible (sframe gframe)
;; (and (equal (g 'pc sframe)
;; (g 'pc gframe))
;; (equal (g 'max-stack sframe)
;; (g 'max-stack gframe))
;; (equal (g 'method-table sframe)
;; (g 'method-table gframe))
;; (sig-opstack-compatible sframe gframe)
;; (sig-local-compatible (g 'locals sframe)
;; (g 'locals gframe))))
(defun all-next-state-safe (sig-frames post-vector)
(if (endp sig-frames) t
(let* ((sig-frame (car sig-frames))
(rest (cdr sig-frames))
(pc (g 'pc sig-frame))
(post (binding pc post-vector)))
(and (sig-frame-compatible
sig-frame
post)
(all-next-state-safe rest post-vector)))))
(defun bcv-simple-inst (pc inst sig-vector)
(let* ((pre-vector sig-vector)
(post-vector sig-vector)
(pre (binding pc pre-vector)))
(and (bcv-simple-check-step-pre inst pre)
(all-next-state-safe
(bcv-simple-execute-step inst pre)
post-vector))))
(defun bcv-simple-method1 (pc code sig-vector)
(declare (xargs :measure (len code)))
(if (endp code) t
(let* ((inst (car code)))
(and (bcv-simple-inst pc inst sig-vector)
(bcv-simple-method1 (+ 1 pc) (cdr code) sig-vector)))))
(defun sig-init-locals (method)
;; tmp, we only deal with number of values on the operand stack!
(declare (ignore method))
nil)
;; (defun sig-method-init-frame (method)
;; (s 'max-stack
;; (g 'max-stack method)
;; (s 'pc 0
;; (s 'op-stack 0
;; (s 'locals
;; (sig-init-locals method) nil)))))
;;; even for such an simple model, we may need to show that execution does not
;;; fell off the end of the code.
;;;
;;; which is not easy! especially, when we our BCV is expressed this way!!
;;;
;;; Sat Oct 8 21:29:41 2005. this is simplified problem, we designed our m-run
;;; to "halt" when the execution fell off the end of code (next instruction is
;;; not well defined), in a real JVM, we need to show execution never "fall"
;;; off the end of the code
(defun bcv-simple-method (method method-table)
(and (sig-frame-compatible
(sig-method-init-frame method method-table)
(binding 0 (g 'sig-vector method)))
(bcv-simple-method1 0
(g 'code method)
(g 'sig-vector method))))
;----------------------------------------------------------------------
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