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;;;; type testing and checking VOPs for the x86 VM
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
(in-package "SB!VM")
;;;; test generation utilities
(defun generate-fixnum-test (value)
(emit-optimized-test-inst value fixnum-tag-mask))
(defun %test-fixnum (value target not-p)
(generate-fixnum-test value)
(inst jmp (if not-p :nz :z) target))
(defun %test-fixnum-and-headers (value target not-p headers)
(let ((drop-through (gen-label)))
(generate-fixnum-test value)
(inst jmp :z (if not-p drop-through target))
(%test-headers value target not-p nil headers drop-through)))
(defun %test-immediate (value target not-p immediate)
;; Code a single instruction byte test if possible.
(let ((offset (tn-offset value)))
(cond ((and (sc-is value any-reg descriptor-reg)
(or (= offset eax-offset) (= offset ebx-offset)
(= offset ecx-offset) (= offset edx-offset)))
(inst cmp (make-random-tn :kind :normal
:sc (sc-or-lose 'byte-reg)
:offset offset)
immediate))
(t
(move eax-tn value)
(inst cmp al-tn immediate))))
(inst jmp (if not-p :ne :e) target))
(defun %test-lowtag (value target not-p lowtag)
(inst lea eax-tn (make-ea :dword :base value :disp (- lowtag)))
(inst test al-tn lowtag-mask)
;; FIXME: another 'optimization' which doesn't appear to work:
;; prefetching the hypothetically pointed-to version should help,
;; but this is in fact non-ideal in plenty of ways: we emit way too
;; many of these prefetch instructions; pointed-to objects are very
;; often in the cache anyway; etc. etc. Still, as proof-of-concept,
;; not too bad. -- CSR, 2004-07-27
(when (member :prefetch *backend-subfeatures*)
(inst prefetchnta (make-ea :byte :base value :disp (- lowtag))))
(inst jmp (if not-p :ne :e) target))
(defun %test-headers (value target not-p function-p headers
&optional (drop-through (gen-label)))
(let ((lowtag (if function-p fun-pointer-lowtag other-pointer-lowtag)))
(multiple-value-bind (equal less-or-equal greater-or-equal when-true when-false)
;; EQUAL, LESS-OR-EQUAL and GREATER-OR-EQUAL are the conditions for
;; branching to TARGET. WHEN-TRUE and WHEN-FALSE are the
;; labels to branch to when we know it's true and when we know
;; it's false respectively.
(if not-p
(values :ne :a :b drop-through target)
(values :e :na :nb target drop-through))
(%test-lowtag value when-false t lowtag)
(cond
((and (null (cdr headers))
(numberp (car headers)))
;; Optimize the common case: referencing the value from memory
;; is slightly smaller than loading it and then doing the
;; comparison. Doing this for other cases (e.g. range of
;; [BIGNUM-WIDETAG..FOO-WIDETAG]) is also possible, but such
;; opportunities don't come up very often and the code would
;; get pretty hairy...
(inst cmp (make-ea :byte :base value :disp (- lowtag)) (car headers))
(inst jmp equal target))
(t
(inst mov al-tn (make-ea :byte :base value :disp (- lowtag)))
(do ((remaining headers (cdr remaining)))
((null remaining))
(let ((header (car remaining))
(last (null (cdr remaining))))
(cond
((atom header)
(cond
((and (not last) (null (cddr remaining))
(atom (cadr remaining))
(= (logcount (logxor header (cadr remaining))) 1))
;; BASE-STRING, (VECTOR NIL), BIT-VECTOR, (VECTOR T)
(inst and al-tn (ldb (byte 8 0) (logeqv header (cadr remaining))))
(inst cmp al-tn (ldb (byte 8 0) (logand header (cadr remaining))))
(inst jmp equal target)
(return))
(t
(inst cmp al-tn header)
(if last
(inst jmp equal target)
(inst jmp :e when-true)))))
(t
(let ((start (car header))
(end (cdr header)))
(cond
;; LAST = don't need al-tn later
((and last (not (= start bignum-widetag))
(= (+ start 4) end) (= (logcount (logxor start end)) 1))
;; SIMPLE-STRING
(inst and al-tn (ldb (byte 8 0) (logeqv start end)))
(inst cmp al-tn (ldb (byte 8 0) (logand start end)))
(inst jmp equal target))
((and (not last) (null (cddr remaining))
(= (+ start 4) end) (= (logcount (logxor start end)) 1)
(listp (cadr remaining))
(= (+ (caadr remaining) 4) (cdadr remaining))
(= (logcount (logxor (caadr remaining) (cdadr remaining))) 1)
(= (logcount (logxor (caadr remaining) start)) 1))
;; STRING
(inst and al-tn (ldb (byte 8 0) (logeqv start (cdadr remaining))))
(inst cmp al-tn (ldb (byte 8 0) (logand start (cdadr remaining))))
(inst jmp equal target)
;; we've shortcircuited the DO, so we must return.
;; It's OK to do so, because (NULL (CDDR REMAINING))
;; was true.
(return))
(t
(cond
((= start bignum-widetag)
(inst cmp al-tn end)
(if last
(inst jmp less-or-equal target)
(inst jmp :be when-true)))
((= end complex-array-widetag)
(inst cmp al-tn start)
(if last
(inst jmp greater-or-equal target)
(inst jmp :b when-false)))
((not last)
(inst cmp al-tn start)
(inst jmp :b when-false)
(inst cmp al-tn end)
(if last
(inst jmp less-or-equal target)
(inst jmp :be when-true)))
(t
(inst sub al-tn start)
(inst cmp al-tn (- end start))
(inst jmp less-or-equal target))))))))))))
(emit-label drop-through))))
;;;; type checking and testing
(define-vop (check-type)
(:args (value :target result :scs (any-reg descriptor-reg)))
(:results (result :scs (any-reg descriptor-reg)))
(:temporary (:sc unsigned-reg :offset eax-offset :to (:result 0)) eax)
(:ignore eax)
(:vop-var vop)
(:save-p :compute-only))
(define-vop (type-predicate)
(:args (value :scs (any-reg descriptor-reg)))
(:temporary (:sc unsigned-reg :offset eax-offset) eax)
(:ignore eax)
(:conditional)
(:info target not-p)
(:policy :fast-safe))
;;; simpler VOP that don't need a temporary register
(define-vop (simple-check-type)
(:args (value :target result :scs (any-reg descriptor-reg)))
(:results (result :scs (any-reg descriptor-reg)
:load-if (not (and (sc-is value any-reg descriptor-reg)
(sc-is result control-stack)))))
(:vop-var vop)
(:save-p :compute-only))
(define-vop (simple-type-predicate)
(:args (value :scs (any-reg descriptor-reg control-stack)))
(:conditional)
(:info target not-p)
(:policy :fast-safe))
(defun cost-to-test-types (type-codes)
(+ (* 2 (length type-codes))
(if (> (apply #'max type-codes) lowtag-limit) 7 2)))
(defmacro !define-type-vops (pred-name check-name ptype error-code
(&rest type-codes)
&key (variant nil variant-p) &allow-other-keys)
;; KLUDGE: UGH. Why do we need this eval? Can't we put this in the
;; expansion?
(let* ((cost (cost-to-test-types (mapcar #'eval type-codes)))
(prefix (if variant-p
(concatenate 'string (string variant) "-")
"")))
`(progn
,@(when pred-name
`((define-vop (,pred-name ,(intern (concatenate 'string prefix "TYPE-PREDICATE")))
(:translate ,pred-name)
(:generator ,cost
(test-type value target not-p (,@type-codes))))))
,@(when check-name
`((define-vop (,check-name ,(intern (concatenate 'string prefix "CHECK-TYPE")))
(:generator ,cost
(let ((err-lab
(generate-error-code vop ',error-code value)))
(test-type value err-lab t (,@type-codes))
(move result value))))))
,@(when ptype
`((primitive-type-vop ,check-name (:check) ,ptype))))))
;;;; other integer ranges
(define-vop (fixnump/unsigned-byte-32 simple-type-predicate)
(:args (value :scs (unsigned-reg)))
(:info)
(:conditional :be)
(:arg-types unsigned-num)
(:translate fixnump)
(:generator 5
;; We could encode this with :Z and SHR, analogously to the signed-byte-32
;; case below -- as we do on x86-64 -- but that costs us an extra
;; register. Compromises...
(inst cmp value #.sb!xc:most-positive-fixnum)))
(define-vop (fixnump/signed-byte-32 type-predicate)
(:args (value :scs (signed-reg)))
(:info)
(:conditional :z)
(:arg-types signed-num)
(:translate fixnump)
(:generator 5
;; Hackers Delight, p. 53: signed
;; a <= x <= a + 2^n - 1
;; is equivalent to unsigned
;; ((x-a) >> n) = 0
(inst mov eax-tn value)
(inst sub eax-tn #.sb!xc:most-negative-fixnum)
(inst shr eax-tn #.(integer-length (- sb!xc:most-positive-fixnum
sb!xc:most-negative-fixnum)))))
;;; A (SIGNED-BYTE 32) can be represented with either fixnum or a bignum with
;;; exactly one digit.
(define-vop (signed-byte-32-p type-predicate)
(:translate signed-byte-32-p)
(:generator 45
(multiple-value-bind (yep nope)
(if not-p
(values not-target target)
(values target not-target))
(generate-fixnum-test value)
(inst jmp :e yep)
(inst lea eax-tn (make-ea :dword :base value
:disp (- other-pointer-lowtag)))
(inst test al-tn lowtag-mask)
(inst jmp :ne nope)
(inst cmp (make-ea-for-object-slot value 0 other-pointer-lowtag)
(+ (ash 1 n-widetag-bits) bignum-widetag))
(inst jmp (if not-p :ne :e) target))
NOT-TARGET))
(define-vop (check-signed-byte-32 check-type)
(:generator 45
(let ((nope (generate-error-code vop
'object-not-signed-byte-32-error
value)))
(generate-fixnum-test value)
(inst jmp :e yep)
(inst lea eax-tn (make-ea :dword :base value
:disp (- other-pointer-lowtag)))
(inst test al-tn lowtag-mask)
(inst jmp :ne nope)
(inst cmp (make-ea-for-object-slot value 0 other-pointer-lowtag)
(+ (ash 1 n-widetag-bits) bignum-widetag))
(inst jmp :ne nope))
YEP
(move result value)))
;;; An (unsigned-byte 32) can be represented with either a positive
;;; fixnum, a bignum with exactly one positive digit, or a bignum with
;;; exactly two digits and the second digit all zeros.
(define-vop (unsigned-byte-32-p type-predicate)
(:translate unsigned-byte-32-p)
(:generator 45
(let ((not-target (gen-label))
(single-word (gen-label))
(fixnum (gen-label)))
(multiple-value-bind (yep nope)
(if not-p
(values not-target target)
(values target not-target))
;; Is it a fixnum?
(move eax-tn value)
(inst test al-tn fixnum-tag-mask)
(inst jmp :e fixnum)
;; If not, is it an other pointer?
(inst and al-tn lowtag-mask)
(inst cmp al-tn other-pointer-lowtag)
(inst jmp :ne nope)
;; Get the header.
(loadw eax-tn value 0 other-pointer-lowtag)
;; Is it one?
(inst cmp eax-tn (+ (ash 1 n-widetag-bits) bignum-widetag))
(inst jmp :e single-word)
;; If it's other than two, we can't be an (unsigned-byte 32)
(inst cmp eax-tn (+ (ash 2 n-widetag-bits) bignum-widetag))
(inst jmp :ne nope)
;; Get the second digit.
(loadw eax-tn value (1+ bignum-digits-offset) other-pointer-lowtag)
;; All zeros, its an (unsigned-byte 32).
(inst test eax-tn eax-tn)
(inst jmp :z yep)
(inst jmp nope)
(emit-label single-word)
;; Get the single digit.
(loadw eax-tn value bignum-digits-offset other-pointer-lowtag)
;; positive implies (unsigned-byte 32).
(emit-label fixnum)
(inst test eax-tn eax-tn)
(inst jmp (if not-p :s :ns) target)
(emit-label not-target)))))
(define-vop (check-unsigned-byte-32 check-type)
(:generator 45
(let ((nope
(generate-error-code vop 'object-not-unsigned-byte-32-error value))
(yep (gen-label))
(fixnum (gen-label))
(single-word (gen-label)))
;; Is it a fixnum?
(generate-fixnum-test value)
(move eax-tn value)
(inst jmp :e fixnum)
;; If not, is it an other pointer?
(inst and al-tn lowtag-mask)
(inst cmp al-tn other-pointer-lowtag)
(inst jmp :ne nope)
;; Get the header.
(loadw eax-tn value 0 other-pointer-lowtag)
;; Is it one?
(inst cmp eax-tn (+ (ash 1 n-widetag-bits) bignum-widetag))
(inst jmp :e single-word)
;; If it's other than two, we can't be an (unsigned-byte 32)
(inst cmp eax-tn (+ (ash 2 n-widetag-bits) bignum-widetag))
(inst jmp :ne nope)
;; Get the second digit.
(loadw eax-tn value (1+ bignum-digits-offset) other-pointer-lowtag)
;; All zeros, its an (unsigned-byte 32).
(inst test eax-tn eax-tn)
(inst jmp :z yep)
(inst jmp nope)
(emit-label single-word)
;; Get the single digit.
(loadw eax-tn value bignum-digits-offset other-pointer-lowtag)
;; positive implies (unsigned-byte 32).
(emit-label fixnum)
(inst test eax-tn eax-tn)
(inst jmp :s nope)
(emit-label yep)
(move result value))))
(defun power-of-two-limit-p (x)
(and (fixnump x)
(= (logcount (1+ x)) 1)))
(define-vop (test-fixnum-mod-power-of-two)
(:args (value :scs (any-reg descriptor-reg
unsigned-reg signed-reg
immediate)))
(:arg-types *
(:constant (satisfies power-of-two-limit-p)))
(:translate sb!c::fixnum-mod-p)
(:conditional :e)
(:info hi)
(:save-p :compute-only)
(:policy :fast-safe)
(:generator 4
(aver (not (sc-is value immediate)))
(let* ((fixnum-hi (if (sc-is value unsigned-reg signed-reg)
hi
(fixnumize hi))))
(inst test value (lognot fixnum-hi)))))
(define-vop (test-fixnum-mod-tagged-unsigned)
(:args (value :scs (any-reg descriptor-reg
unsigned-reg signed-reg
immediate)))
(:arg-types (:or tagged-num unsigned-num signed-num)
(:constant fixnum))
(:translate sb!c::fixnum-mod-p)
(:conditional :be)
(:info hi)
(:save-p :compute-only)
(:policy :fast-safe)
(:generator 5
(aver (not (sc-is value immediate)))
(let ((fixnum-hi (if (sc-is value unsigned-reg signed-reg)
hi
(fixnumize hi))))
(inst cmp value fixnum-hi))))
(define-vop (test-fixnum-mod-*)
(:args (value :scs (any-reg descriptor-reg)))
(:arg-types * (:constant fixnum))
(:translate sb!c::fixnum-mod-p)
(:conditional)
(:info target not-p hi)
(:save-p :compute-only)
(:policy :fast-safe)
(:generator 6
(let* ((fixnum-hi (fixnumize hi))
(skip (gen-label)))
(generate-fixnum-test value)
(inst jmp :ne (if not-p target skip))
(inst cmp value fixnum-hi)
(inst jmp (if not-p :a :be) target)
(emit-label skip))))
;;;; list/symbol types
;;;
;;; symbolp (or symbol (eq nil))
;;; consp (and list (not (eq nil)))
(define-vop (symbolp type-predicate)
(:translate symbolp)
(:generator 12
(let ((is-symbol-label (if not-p DROP-THRU target))
(widetag-tn (make-ea :byte :base value :disp (- other-pointer-lowtag))))
;; It could have been done with just TEST-TYPE, but using CMP on
;; EAX saves one byte, this basically unrolls TEST-TYPE and
;; inserts a comparison to NIL in the middle.
(inst lea eax-tn widetag-tn)
(inst cmp eax-tn (- nil-value other-pointer-lowtag))
(inst jmp :e is-symbol-label)
(inst test al-tn other-pointer-lowtag)
(inst jmp :nz (if not-p target drop-thru))
(inst cmp widetag-tn symbol-header-widetag)
(inst jmp (if not-p :ne :e) target))
DROP-THRU))
(define-vop (check-symbol check-type)
(:generator 12
(let ((error (generate-error-code vop 'object-not-symbol-error value))
(widetag-tn (make-ea :byte :base value :disp (- other-pointer-lowtag))))
(inst lea eax-tn widetag-tn)
(inst cmp eax-tn (- nil-value other-pointer-lowtag))
(inst jmp :e drop-thru)
(inst test al-tn other-pointer-lowtag)
(inst jmp :nz error)
(inst cmp widetag-tn symbol-header-widetag)
(inst jmp :ne error))
DROP-THRU
(move result value)))
(define-vop (consp type-predicate)
(:translate consp)
(:generator 8
(let ((is-not-cons-label (if not-p target drop-thru)))
;; It could have been done with just TEST-TYPE, but using CMP on
;; EAX saves one byte, this basically unrolls TEST-TYPE and
;; inserts a comparison to NIL in the middle.
(inst lea eax-tn (make-ea :dword :base value :disp (- list-pointer-lowtag)))
(inst cmp eax-tn (- nil-value list-pointer-lowtag))
(inst jmp :e is-not-cons-label)
(inst test al-tn other-pointer-lowtag)
(inst jmp (if not-p :nz :z) target))
DROP-THRU))
(define-vop (check-cons check-type)
(:generator 8
(let ((error (generate-error-code vop 'object-not-cons-error value)))
(inst lea eax-tn (make-ea :dword :base value :disp (- list-pointer-lowtag)))
(inst cmp eax-tn (- nil-value list-pointer-lowtag))
(inst jmp :e error)
(inst test al-tn other-pointer-lowtag)
(inst jmp :nz error)
(move result value))))