/usr/share/scheme48-1.9/env/parse-bytecode.scm is in scheme48 1.9-5.
This file is owned by root:root, with mode 0o644.
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; Authors: Martin Gasbichler, Mike Sperber
;; Generic byte code parser
(define-record-type attribution :attribution
(make-attribution init-template template-literal
opcode-table make-label at-label)
attribution?
(init-template attribution-init-template)
(template-literal attribution-template-literal)
(opcode-table attribution-opcode-table)
(make-label attribution-make-label)
(at-label attribution-at-label))
(define (opcode-table-ref table i)
(vector-ref table i))
(define (opcode-table-set! table i new)
(vector-set! table i new))
(define (make-opcode-table default)
(make-vector op-count default))
;; Example attribution
(define (disass)
(define (disass-init-template state template p-args push-template? push-env? push-closure?)
(cons (list 0 'protocol p-args push-template? push-env? push-closure?)
state))
(define instruction-set-table
(make-opcode-table
(lambda (opcode template state pc len . args)
(cons `(,pc ,(enumerand->name opcode op) ,@(map cdr args)) state))))
(define (attribute-literal literal i state)
state)
(define (make-label target-pc)
target-pc)
(define (at-label label state)
(cons `(,label :) state))
(make-attribution disass-init-template attribute-literal
instruction-set-table make-label at-label))
(define (parse-template x state attribution)
(let* ((tem (coerce-to-template x))
(template-len (template-length tem)))
(let lp ((i 1) (state state))
(if (= i template-len)
(parse-template-code tem (template-code tem) state attribution)
(let ((literal (template-ref tem i)))
(if (template? literal)
(lp (+ i 1) (parse-template literal state attribution))
(lp (+ i 1) ((attribution-template-literal attribution) literal i state))))))))
(define (byte-code? x)
(let ((code (template-code (coerce-to-template x))))
(define (byte-code-protocol? protocol)
(or (<= protocol maximum-stack-args)
(= protocol two-byte-nargs-protocol)
(= protocol two-byte-nargs+list-protocol)
(= protocol ignore-values-protocol)
(= protocol call-with-values-protocol)
(= protocol args+nargs-protocol)
(= protocol nary-dispatch-protocol)
(and (= protocol big-stack-protocol)
(byte-code-protocol?
(code-vector-ref code (- (code-vector-length code) 3))))))
(byte-code-protocol? (code-vector-ref code 1))))
(define (parse-template-code tem code state attribution)
(with-template
tem code state attribution
(lambda (pc length state)
(let loop ((pc pc)
(state state))
(if (< pc length)
(receive (size state)
(parse-instruction tem code pc state attribution)
(loop (+ pc size) state))
state)))))
(define (with-template tem code state attribution fun)
(let ((length (template-code-length code)))
(let-fluid
*bc-make-labels* '()
(lambda ()
(for-each
(lambda (pc) (pc->label pc attribution))
(debug-data-jump-back-dests (template-debug-data tem)))
(receive (size protocol-arguments)
(parse-protocol code 1 attribution)
(receive (push-template? push-env? push-closure?)
(case (code-vector-ref code (+ size 1))
((#b000) (values #f #f #f))
((#b001) (values #t #f #f))
((#b010) (values #f #t #f))
((#b011) (values #t #t #f))
((#b100) (values #f #f #t))
((#b110) (values #f #t #t))
((#b101) (values #t #f #t))
((#b111) (values #t #t #t))
(else (assertion-violation 'with-template "invalid init-template spec"
(code-vector-ref code (+ size 1)))))
(fun (+ size 2)
length
((attribution-init-template attribution)
state tem protocol-arguments push-template? push-env? push-closure?))))))))
(define (parse-instruction template code pc state attribution)
(let* ((opcode (code-vector-ref code pc))
(len.rev-args (cond ((= opcode (enum op computed-goto)) ; unused?
(assertion-violation 'parse-instruction
"computed-goto in parse-bytecode"))
(else
(parse-opcode-args opcode
pc
code
template
attribution))))
(total-len (+ 1 (car len.rev-args)))) ; 1 for the opcode
(values total-len
(really-parse-instruction pc total-len opcode template state
(reverse (cdr len.rev-args)) attribution))))
(define (really-parse-instruction pc len opcode template state args attribution)
(let ((new-state (if (label-at-pc? pc)
((attribution-at-label attribution)
(pc->label pc attribution)
state)
state)))
(let ((opcode-attribution
(opcode-table-ref (attribution-opcode-table attribution) opcode)))
(if opcode-attribution
(apply opcode-attribution opcode template new-state pc len args)
(assertion-violation 'parse-instruction "cannot attribute "
(enumerand->name opcode op) args)))))
;;--------------------
;; labels
(define *bc-make-labels* (make-fluid '()))
(define (add-pc! pc attribution)
(set-fluid! *bc-make-labels*
(cons (cons pc ((attribution-make-label attribution) pc))
(fluid *bc-make-labels*))))
(define (pc->label pc attribution)
(let ((maybe-pc.label (assq pc (fluid *bc-make-labels*))))
(if maybe-pc.label
(cdr maybe-pc.label)
(begin
(add-pc! pc attribution)
(pc->label pc attribution)))))
(define (label-at-pc? pc)
(if (assq pc (fluid *bc-make-labels*)) #t #f))
; (enum op make-[big-]flat-env)
; number of vars
; number of closures
; [offset of template in frame
; offsets of templates in template]
; number of variables in frame (size)
; offsets of vars in frame
; [offset of env in frame
; number of vars in env
; offsets of vars in level]*
(define-record-type env-data :env-data
(make-env-data total-count frame-offsets maybe-template-index closure-offsets
env-offsets)
env-data?
(total-count env-data-total-count)
(frame-offsets env-data-frame-offsets)
(maybe-template-index env-data-maybe-template-index)
(closure-offsets env-data-closure-offsets)
(env-offsets env-data-env-offsets))
(define (parse-flat-env-args pc code size fetch)
(let ((start-pc pc)
(total-count (fetch code pc))
(closure-count (fetch code (+ pc size))))
(receive (template-index closure-offsets)
(if (< 0 closure-count)
(values (fetch code (+ pc size size))
(get-offsets code (+ pc size size size)
size fetch closure-count))
(values #f '()))
(let* ((pc (if (< 0 closure-count)
(+ pc
(* 2 size) ; counts
size ; template offset
(* closure-count size)) ; subtemplates
(+ pc (* 2 size)))) ; counts
(frame-count (fetch code pc))
(pc (+ pc size)))
(let ((frame-offsets (get-offsets code pc size fetch frame-count)))
(let ((pc (+ pc (* frame-count size)))
(count (+ closure-count frame-count)))
(let loop ((pc pc) (count count) (rev-env-offsets '()))
(if (= count total-count)
(values (- pc start-pc)
(make-env-data total-count frame-offsets
template-index closure-offsets
(reverse rev-env-offsets)))
(let* ((env (fetch code pc))
(count-here (fetch code (+ pc size)))
(indexes (get-offsets code
(+ pc size size)
size
fetch
count-here)))
(loop (+ pc (* (+ 2 count-here) size))
(+ count count-here)
(cons (cons env indexes) rev-env-offsets)))))))))))
(define (get-offsets code pc size fetch count)
(do ((pc pc (+ pc size))
(i 0 (+ i 1))
(r '() (cons (fetch code pc) r)))
((= i count)
(reverse r))))
; Parse a protocol, returning the number of bytes of instruction stream that
; were consumed. PC has to point behind the PRTOCOL opcode
(define (parse-protocol code pc attribution)
(let ((protocol (code-vector-ref code pc)))
(really-parse-protocol protocol code pc attribution)))
(define (really-parse-protocol protocol code pc attribution)
(cond ((<= protocol maximum-stack-args)
(values 1 (list protocol)))
((= protocol two-byte-nargs-protocol)
(values 3 (list protocol (get-offset code (+ pc 1)))))
((= protocol two-byte-nargs+list-protocol)
(values 3 (list protocol (get-offset code (+ pc 1)))))
((= protocol ignore-values-protocol)
(values 1 (list protocol)))
((= protocol call-with-values-protocol)
(let ((offset (get-offset code (+ pc 1))))
(values 3 (list protocol
(pc->label (- (+ offset pc) 1)
attribution)
(zero? offset)))))
((= protocol args+nargs-protocol)
(values 2 (list protocol (code-vector-ref code (+ pc 1)))))
((= protocol nary-dispatch-protocol)
(values 5 (cons protocol (parse-dispatch code pc attribution))))
((= protocol big-stack-protocol)
(let ((real-protocol (code-vector-ref code
(- (code-vector-length code) 3)))
(stack-size (get-offset code (- (code-vector-length code) 2))))
(receive (size real-attribution)
(really-parse-protocol real-protocol code pc attribution)
(values size
(list protocol real-attribution stack-size)))))
(else
(assertion-violation 'parse-protocol "unknown protocol" protocol pc))))
(define (parse-dispatch code pc attribution)
(define (maybe-parse-one-dispatch index)
(let ((offset (code-vector-ref code (+ pc index))))
(if (= offset 0)
#f
(pc->label (+ offset pc) attribution))))
(map maybe-parse-one-dispatch (list 3 4 5 2)))
(define (protocol-protocol p-args)
(car p-args))
(define (n-ary-protocol? p-args)
(let ((protocol (car p-args)))
(if (or (= protocol two-byte-nargs+list-protocol)
(= protocol call-with-values-protocol)
(= protocol ignore-values-protocol))
#t
(if (or (<= protocol maximum-stack-args)
(= protocol two-byte-nargs-protocol))
#f
(if (= protocol big-stack-protocol)
(n-ary-protocol? (cadr p-args))
(assertion-violation 'n-ary-protocol?
"unknown protocol" p-args))))))
(define (protocol-nargs p-args)
(let ((protocol (car p-args)))
(cond ((<= protocol maximum-stack-args)
protocol)
((= protocol two-byte-nargs-protocol)
(cadr p-args))
((= protocol two-byte-nargs+list-protocol)
(cadr p-args))
((= protocol args+nargs-protocol)
(cadr p-args))
((= protocol big-stack-protocol)
(protocol-nargs (cadr p-args)))
((= protocol ignore-values-protocol)
0)
((= protocol call-with-values-protocol)
(assertion-violation 'protocol-nargs
"call-with-values-protocol in protocol-nargs"))
(else
(assertion-violation 'protocol-nargs
"unknown protocol" p-args)))))
(define (protocol-cwv-tailcall? p-args)
(let ((protocol (protocol-protocol p-args)))
(if (not (= protocol call-with-values-protocol))
(assertion-violation 'protocol-cwv-tailcall?
"invalid protocol" protocol))
(caddr p-args)))
(define (call-with-values-protocol-target p-args)
(let ((protocol (protocol-protocol p-args)))
(if (not (= protocol call-with-values-protocol))
(assertion-violation 'call-with-values-protocol-target
"invalid protocol" protocol))
(cadr p-args)))
; Generic opcode argument parser
(define (parse-opcode-args op start-pc code template attribution)
(let ((specs (vector-ref opcode-arg-specs op)))
(let loop ((specs specs) (pc (+ start-pc 1)) (len 0) (args '()))
(if (null? specs)
(cons len args)
(let ((spec (car specs)))
(cond
((eq? spec 'protocol)
(receive (size p-args)
(parse-protocol code pc attribution)
(loop (cdr specs)
(+ pc size)
(+ len size)
(cons (cons 'protocol p-args) args))))
((or (eq? spec 'env-data)
(eq? spec 'big-env-data))
(receive (size env-data)
(receive (slot-size fetch)
(if (eq? spec 'env-data)
(values 1 code-vector-ref)
(values 2 get-offset))
(parse-flat-env-args pc code slot-size fetch))
(loop (cdr specs)
(+ pc size)
(+ len size)
(cons (cons 'env-data env-data) args))))
((eq? spec 'instr)
(let ((opcode (code-vector-ref code pc)))
(let ((len.revargs (parse-opcode-args opcode
pc
code
template
attribution)))
(loop (cdr specs)
(+ pc 1 (car len.revargs))
(+ len 1 (car len.revargs))
(cons
(cons 'instr
(cons opcode (reverse (cdr len.revargs))))
args)))))
((= 0 (arg-spec-size spec pc code))
(cons len args))
(else
(let ((arg (parse-opcode-arg specs
pc
start-pc
code
template
attribution)))
(loop (cdr specs)
(+ pc (arg-spec-size spec pc code))
(+ len (arg-spec-size spec pc code))
(cons arg args))))))))))
; The number of bytes required by an argument.
(define (arg-spec-size spec pc code)
(case spec
((byte nargs stack-index index literal stob) 1)
((two-bytes two-byte-nargs two-byte-stack-index two-byte-index offset offset-) 2)
((env-data) (assertion-violation 'arg-spec-size "env-data in arg-spec-size"))
((protocol) (assertion-violation 'arg-spec-size "protocol in arg-spec-size"))
((moves-data)
(let ((n-moves (code-vector-ref code pc)))
(+ 1 (* 2 n-moves))))
((big-moves-data)
(let ((n-moves (code-vector-ref code pc)))
(+ 2 (* 4 n-moves))))
((cont-data)
(- (get-offset code pc) 1)) ; size includes opcode
(else 0)))
; Parse the particular type of argument.
(define (parse-opcode-arg specs pc start-pc code template attribution)
(cons
(car specs)
(case (car specs)
((byte nargs stack-index index)
(code-vector-ref code pc))
((two-bytes two-byte-nargs two-byte-stack-index two-byte-index)
(get-offset code pc))
((literal)
(- (code-vector-ref code pc) 128))
((offset)
(let ((offset (get-offset code pc)))
(if (zero? offset)
#f
(pc->label (+ start-pc offset) attribution))))
((offset-)
(pc->label (- start-pc (get-offset code pc)) attribution))
((stob)
(code-vector-ref code pc))
((cont-data)
(parse-cont-data-args pc code template attribution))
((moves-data)
(let ((n-moves (code-vector-ref code pc)))
(let loop ((offset (+ pc 1))
(n n-moves))
(if (zero? n)
'()
(cons (cons (code-vector-ref code offset)
(code-vector-ref code (+ offset 1)))
(loop (+ offset 2) (- n 1)))))))
((big-moves-data)
(let ((n-moves (get-offset code pc)))
(let loop ((offset (+ pc 2))
(n n-moves))
(if (zero? n)
'()
(cons (cons (get-offset code offset)
(get-offset code (+ offset 2)))
(loop (+ offset 4) (- n 1)))))))
(else (assertion-violation 'parse-opcode-arg
"unknown arg spec: " (car specs))))))
(define-record-type cont-data :cont-data
(make-cont-data length mask-bytes live-offsets template pc gc-mask-size depth)
cont-data?
(length cont-data-length)
(mask-bytes cont-data-mask-bytes)
;; #f if all are live
(live-offsets cont-data-live-offsets)
(template cont-data-template)
(pc cont-data-pc)
(gc-mask-size cont-data-gc-mask-size)
(depth cont-data-depth))
(define (parse-cont-data-args pc code template attribution)
(let* ((len (get-offset code pc))
(end-pc (- (+ pc len) 1)) ; len includes opcode
(gc-mask-size (code-vector-ref code (- end-pc 3)))
(depth (get-offset code (- end-pc 2)))
(offset (get-offset code (- end-pc 5)))
(template (get-offset code (- end-pc 7)))
(mask-bytes
(let lp ((the-pc (+ pc 2)) (mask-bytes '()))
(if (>= the-pc (+ pc 2 gc-mask-size))
mask-bytes
(lp (+ the-pc 1)
(cons (code-vector-ref code the-pc) mask-bytes)))))
(live-offsets
(and (not (zero? gc-mask-size))
(gc-mask-live-offsets (bytes->bits mask-bytes)))))
(make-cont-data len
mask-bytes
live-offsets
template
(pc->label offset attribution)
gc-mask-size
depth)))
(define (bytes->bits l)
(let loop ((n 0) (l l))
(if (null? l)
n
(loop (+ (arithmetic-shift n 8) (car l))
(cdr l)))))
(define (gc-mask-live-offsets mask)
(let loop ((mask mask) (i 0) (l '()))
(if (zero? mask)
(reverse l)
(loop (arithmetic-shift mask -1) (+ 1 i)
(if (odd? mask)
(cons i l)
l)))))
;----------------
; Utilities.
; TODO: Put the template-related stuff into a separate module?
; Turn OBJ into a template, if possible.
(define (coerce-to-template obj)
(cond ((template? obj) obj)
((closure? obj) (closure-template obj))
((continuation? obj) (continuation-template obj))
(else (assertion-violation 'coerce-to-template
"expected a procedure or continuation" obj))))
(define (template-code-length code)
(if (and (= (enum op protocol)
(code-vector-ref code 0))
(= big-stack-protocol
(code-vector-ref code 1)))
(- (code-vector-length code) 3)
(code-vector-length code)))
; Fetch the two-byte value at PC in CODE.
(define (get-offset code pc)
(+ (* (code-vector-ref code pc)
byte-limit)
(code-vector-ref code (+ pc 1))))
|