vm-tran.lisp

开源跨平台Lisp编译器

;;;; implementation-dependent transforms

;;;; 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!C")

;;; We need to define these predicates, since the TYPEP source
;;; transform picks whichever predicate was defined last when there
;;; are multiple predicates for equivalent types.
(define-source-transform short-float-p (x) `(single-float-p ,x))
#!-long-float
(define-source-transform long-float-p (x) `(double-float-p ,x))

(define-source-transform compiled-function-p (x)
  #!-sb-eval
  `(functionp ,x)
  #!+sb-eval
  (once-only ((x x))
    `(and (functionp ,x)
          (not (sb!eval:interpreted-function-p ,x)))))

(define-source-transform char-int (x)
  `(char-code ,x))

(deftransform abs ((x) (rational))
  '(if (< x 0) (- x) x))

;;; We don't want to clutter the bignum code.
#!+(or x86 x86-64)
(define-source-transform sb!bignum:%bignum-ref (bignum index)
  ;; KLUDGE: We use TRULY-THE here because even though the bignum code
  ;; is (currently) compiled with (SAFETY 0), the compiler insists on
  ;; inserting CAST nodes to ensure that INDEX is of the correct type.
  ;; These CAST nodes do not generate any type checks, but they do
  ;; interfere with the operation of FOLD-INDEX-ADDRESSING, below.
  ;; This scenario is a problem for the more user-visible case of
  ;; folding as well.  --njf, 2006-12-01
  `(sb!bignum:%bignum-ref-with-offset ,bignum
                                      (truly-the bignum-index ,index) 0))

#!+(or x86 x86-64)
(defun fold-index-addressing (fun-name element-size lowtag data-offset
                              index offset &optional setter-p)
  (multiple-value-bind (func index-args) (extract-fun-args index '(+ -) 2)
    (destructuring-bind (x constant) index-args
      (declare (ignorable x))
      (unless (constant-lvar-p constant)
        (give-up-ir1-transform))
      (let ((value (lvar-value constant)))
        (unless (and (integerp value)
                     (sb!vm::foldable-constant-offset-p
                      element-size lowtag data-offset
                      (funcall func value (lvar-value offset))))
          (give-up-ir1-transform "constant is too large for inlining"))
        (splice-fun-args index func 2)
        `(lambda (thing index off1 off2 ,@(when setter-p
                                            '(value)))
           (,fun-name thing index (,func off2 off1) ,@(when setter-p
                                                        '(value))))))))

#!+(or x86 x86-64)
(deftransform sb!bignum:%bignum-ref-with-offset
    ((bignum index offset) * * :node node)
  (fold-index-addressing 'sb!bignum:%bignum-ref-with-offset
                         sb!vm:n-word-bits sb!vm:other-pointer-lowtag
                         sb!vm:bignum-digits-offset
                         index offset))

#!+x86
(progn
(define-source-transform sb!kernel:%vector-raw-bits (thing index)
  `(sb!kernel:%raw-bits-with-offset ,thing ,index 2))

(define-source-transform sb!kernel:%raw-bits (thing index)
  `(sb!kernel:%raw-bits-with-offset ,thing ,index 0))

(define-source-transform sb!kernel:%set-vector-raw-bits (thing index value)
  `(sb!kernel:%set-raw-bits-with-offset ,thing ,index 2 ,value))

(define-source-transform sb!kernel:%set-raw-bits (thing index value)
  `(sb!kernel:%set-raw-bits-with-offset ,thing ,index 0 ,value))

(deftransform sb!kernel:%raw-bits-with-offset ((thing index offset) * * :node node)
  (fold-index-addressing 'sb!kernel:%raw-bits-with-offset
                         sb!vm:n-word-bits sb!vm:other-pointer-lowtag
                         0 index offset))

(deftransform sb!kernel:%set-raw-bits-with-offset ((thing index offset value) * *)
  (fold-index-addressing 'sb!kernel:%set-raw-bits-with-offset
                         sb!vm:n-word-bits sb!vm:other-pointer-lowtag
                         0 index offset t))
) ; PROGN

;;; The layout is stored in slot 0.
(define-source-transform %instance-layout (x)
  `(truly-the layout (%instance-ref ,x 0)))
(define-source-transform %set-instance-layout (x val)
  `(%instance-set ,x 0 (the layout ,val)))
(define-source-transform %funcallable-instance-layout (x)
  `(truly-the layout (%funcallable-instance-info ,x 0)))
(define-source-transform %set-funcallable-instance-layout (x val)
  `(setf (%funcallable-instance-info ,x 0) (the layout ,val)))

;;;; character support

;;; In our implementation there are really only BASE-CHARs.
#+nil
(define-source-transform characterp (obj)
  `(base-char-p ,obj))

;;;; simplifying HAIRY-DATA-VECTOR-REF and HAIRY-DATA-VECTOR-SET

(deftransform hairy-data-vector-ref ((string index) (simple-string t))
  (let ((ctype (lvar-type string)))
    (if (array-type-p ctype)
        ;; the other transform will kick in, so that's OK
        (give-up-ir1-transform)
        `(etypecase string
          ((simple-array character (*))
           (data-vector-ref string index))
          #!+sb-unicode
          ((simple-array base-char (*))
           (data-vector-ref string index))
          ((simple-array nil (*))
           (data-vector-ref string index))))))

(deftransform hairy-data-vector-ref ((array index) (array t) *)
  "avoid runtime dispatch on array element type"
  (let ((element-ctype (extract-upgraded-element-type array))
        (declared-element-ctype (extract-declared-element-type array)))
    (declare (type ctype element-ctype))
    (when (eq *wild-type* element-ctype)
      (give-up-ir1-transform
       "Upgraded element type of array is not known at compile time."))
    ;; (The expansion here is basically a degenerate case of
    ;; WITH-ARRAY-DATA. Since WITH-ARRAY-DATA is implemented as a
    ;; macro, and macros aren't expanded in transform output, we have
    ;; to hand-expand it ourselves.)
    (let* ((element-type-specifier (type-specifier element-ctype)))
      `(multiple-value-bind (array index)
           (%data-vector-and-index array index)
         (declare (type (simple-array ,element-type-specifier 1) array))
         ,(let ((bare-form '(data-vector-ref array index)))
            (if (type= element-ctype declared-element-ctype)
                bare-form
                `(the ,(type-specifier declared-element-ctype)
                      ,bare-form)))))))

;;; Transform multi-dimensional array to one dimensional data vector
;;; access.
(deftransform data-vector-ref ((array index) (simple-array t))
  (let ((array-type (lvar-type array)))
    (unless (array-type-p array-type)
      (give-up-ir1-transform))
    (let ((dims (array-type-dimensions array-type)))
      (when (or (atom dims) (= (length dims) 1))
        (give-up-ir1-transform))
      (let ((el-type (array-type-specialized-element-type array-type))
            (total-size (if (member '* dims)
                            '*
                            (reduce #'* dims))))
        `(data-vector-ref (truly-the (simple-array ,(type-specifier el-type)
                                                   (,total-size))
                                     (%array-data-vector array))
                          index)))))

;;; Transform data vector access to a form that opens up optimization
;;; opportunities. On platforms that support DATA-VECTOR-REF-WITH-OFFSET
;;; DATA-VECTOR-REF is not supported at all.
#!+(or x86 x86-64)
(define-source-transform data-vector-ref (array index)
  `(data-vector-ref-with-offset ,array ,index 0))

#!+(or x86 x86-64)
(deftransform data-vector-ref-with-offset ((array index offset))
  (let ((array-type (lvar-type array)))
    (when (or (not (array-type-p array-type))
              (eql (array-type-specialized-element-type array-type)
                   *wild-type*))
      (give-up-ir1-transform))
    ;; It shouldn't be possible to get here with anything but a non-complex
    ;; vector.
    (aver (not (array-type-complexp array-type)))
    (let* ((element-type (type-specifier (array-type-specialized-element-type array-type)))
           (saetp (find-saetp element-type)))
      (when (< (sb!vm:saetp-n-bits saetp) sb!vm:n-byte-bits)
        (give-up-ir1-transform))
      (fold-index-addressing 'data-vector-ref-with-offset
                             (sb!vm:saetp-n-bits saetp)
                             sb!vm:other-pointer-lowtag
                             sb!vm:vector-data-offset
                             index offset))))

(deftransform hairy-data-vector-set ((string index new-value)
                                     (simple-string t t))
  (let ((ctype (lvar-type string)))
    (if (array-type-p ctype)
        ;; the other transform will kick in, so that's OK
        (give-up-ir1-transform)
        `(etypecase string
          ((simple-array character (*))
           (data-vector-set string index new-value))
          #!+sb-unicode
          ((simple-array base-char (*))
           (data-vector-set string index new-value))
          ((simple-array nil (*))
           (data-vector-set string index new-value))))))

(deftransform hairy-data-vector-set ((array index new-value)
                                     (array t t)
                                     *)
  "avoid runtime dispatch on array element type"
  (let ((element-ctype (extract-upgraded-element-type array))
        (declared-element-ctype (extract-declared-element-type array)))
    (declare (type ctype element-ctype))
    (when (eq *wild-type* element-ctype)
      (give-up-ir1-transform
       "Upgraded element type of array is not known at compile time."))
    (let ((element-type-specifier (type-specifier element-ctype)))
      `(multiple-value-bind (array index)
           (%data-vector-and-index array index)
         (declare (type (simple-array ,element-type-specifier 1) array)
                  (type ,element-type-specifier new-value))
         ,(if (type= element-ctype declared-element-ctype)
              '(data-vector-set array index new-value)
              `(truly-the ,(type-specifier declared-element-ctype)
                 (data-vector-set array index
                  (the ,(type-specifier declared-element-ctype)
                       new-value))))))))

;;; Transform multi-dimensional array to one dimensional data vector
;;; access.
(deftransform data-vector-set ((array index new-value)
                               (simple-array t t))
  (let ((array-type (lvar-type array)))
    (unless (array-type-p array-type)
      (give-up-ir1-transform))
    (let ((dims (array-type-dimensions array-type)))
      (when (or (atom dims) (= (length dims) 1))
        (give-up-ir1-transform))
      (let ((el-type (array-type-specialized-element-type array-type))
            (total-size (if (member '* dims)
                            '*
                            (reduce #'* dims))))
        `(data-vector-set (truly-the (simple-array ,(type-specifier el-type)
                                                   (,total-size))
                                     (%array-data-vector array))
                          index
                          new-value)))))