;;; The result value is cached in the LVAR-%DERIVED-TYPE slot. If the
;;; slot is true, just return that value, otherwise recompute and
;;; stash the value there.
+(eval-when (:compile-toplevel :execute)
+ (#+sb-xc-host cl:defmacro
+ #-sb-xc-host sb!xc:defmacro
+ lvar-type-using (lvar accessor)
+ `(let ((uses (lvar-uses ,lvar)))
+ (cond ((null uses) *empty-type*)
+ ((listp uses)
+ (do ((res (,accessor (first uses))
+ (values-type-union (,accessor (first current))
+ res))
+ (current (rest uses) (rest current)))
+ ((or (null current) (eq res *wild-type*))
+ res)))
+ (t
+ (,accessor uses))))))
+
#!-sb-fluid (declaim (inline lvar-derived-type))
(defun lvar-derived-type (lvar)
(declare (type lvar lvar))
(setf (lvar-%derived-type lvar)
(%lvar-derived-type lvar))))
(defun %lvar-derived-type (lvar)
- (declare (type lvar lvar))
- (let ((uses (lvar-uses lvar)))
- (cond ((null uses) *empty-type*)
- ((listp uses)
- (do ((res (node-derived-type (first uses))
- (values-type-union (node-derived-type (first current))
- res))
- (current (rest uses) (rest current)))
- ((or (null current) (eq res *wild-type*))
- res)))
- (t
- (node-derived-type uses)))))
+ (lvar-type-using lvar node-derived-type))
;;; Return the derived type for LVAR's first value. This is guaranteed
;;; not to be a VALUES or FUNCTION type.
(defun lvar-type (lvar)
(single-value-type (lvar-derived-type lvar)))
+;;; LVAR-CONSERVATIVE-TYPE
+;;;
+;;; Certain types refer to the contents of an object, which can
+;;; change without type derivation noticing: CONS types and ARRAY
+;;; types suffer from this:
+;;;
+;;; (let ((x (the (cons fixnum fixnum) (cons a b))))
+;;; (setf (car x) c)
+;;; (+ (car x) (cdr x)))
+;;;
+;;; Python doesn't realize that the SETF CAR can change the type of X -- so we
+;;; cannot use LVAR-TYPE which gets the derived results. Worse, still, instead
+;;; of (SETF CAR) we might have a call to a user-defined function FOO which
+;;; does the same -- so there is no way to use the derived information in
+;;; general.
+;;;
+;;; So, the conservative option is to use the derived type if the leaf has
+;;; only a single ref -- in which case there cannot be a prior call that
+;;; mutates it. Otherwise we use the declared type or punt to the most general
+;;; type we know to be correct for sure.
+(defun lvar-conservative-type (lvar)
+ (let ((derived-type (lvar-type lvar))
+ (t-type *universal-type*))
+ ;; Recompute using NODE-CONSERVATIVE-TYPE instead of derived type if
+ ;; necessary -- picking off some easy cases up front.
+ (cond ((or (eq derived-type t-type)
+ ;; Can't use CSUBTYPEP!
+ (type= derived-type (specifier-type 'list))
+ (type= derived-type (specifier-type 'null)))
+ derived-type)
+ ((and (cons-type-p derived-type)
+ (eq t-type (cons-type-car-type derived-type))
+ (eq t-type (cons-type-cdr-type derived-type)))
+ derived-type)
+ ((and (array-type-p derived-type)
+ (or (not (array-type-complexp derived-type))
+ (let ((dimensions (array-type-dimensions derived-type)))
+ (or (eq '* dimensions)
+ (every (lambda (dim) (eq '* dim)) dimensions)))))
+ derived-type)
+ ((type-needs-conservation-p derived-type)
+ (single-value-type (lvar-type-using lvar node-conservative-type)))
+ (t
+ derived-type))))
+
+(defun node-conservative-type (node)
+ (let* ((derived-values-type (node-derived-type node))
+ (derived-type (single-value-type derived-values-type)))
+ (if (ref-p node)
+ (let ((leaf (ref-leaf node)))
+ (if (and (basic-var-p leaf)
+ (cdr (leaf-refs leaf)))
+ (coerce-to-values
+ (if (eq :declared (leaf-where-from leaf))
+ (leaf-type leaf)
+ (conservative-type derived-type)))
+ derived-values-type))
+ derived-values-type)))
+
+(defun conservative-type (type)
+ (cond ((or (eq type *universal-type*)
+ (eq type (specifier-type 'list))
+ (eq type (specifier-type 'null)))
+ type)
+ ((cons-type-p type)
+ (specifier-type 'cons))
+ ((array-type-p type)
+ (if (array-type-complexp type)
+ (make-array-type
+ ;; ADJUST-ARRAY may change dimensions, but rank stays same.
+ :dimensions
+ (let ((old (array-type-dimensions type)))
+ (if (eq '* old)
+ old
+ (mapcar (constantly '*) old)))
+ ;; Complexity cannot change.
+ :complexp (array-type-complexp type)
+ ;; Element type cannot change.
+ :element-type (array-type-element-type type)
+ :specialized-element-type (array-type-specialized-element-type type))
+ ;; Simple arrays cannot change at all.
+ type))
+ (t
+ ;; If the type contains some CONS types, the conservative type contains all
+ ;; of them.
+ (when (types-equal-or-intersect type (specifier-type 'cons))
+ (setf type (type-union type (specifier-type 'cons))))
+ ;; Similarly for non-simple arrays -- it should be possible to preserve
+ ;; more information here, but really...
+ (let ((non-simple-arrays (specifier-type '(and array (not simple-array)))))
+ (when (types-equal-or-intersect type non-simple-arrays)
+ (setf type (type-union type non-simple-arrays))))
+ type)))
+
+(defun type-needs-conservation-p (type)
+ (cond ((eq type *universal-type*)
+ ;; Excluding T is necessary, because we do want type derivation to
+ ;; be able to narrow it down in case someone (most like a macro-expansion...)
+ ;; actually declares something as having type T.
+ nil)
+ ((or (cons-type-p type) (and (array-type-p type) (array-type-complexp type)))
+ ;; Covered by the next case as well, but this is a quick test.
+ t)
+ ((types-equal-or-intersect type (specifier-type '(or cons (and array (not simple-array)))))
+ t)))
+
;;; If LVAR is an argument of a function, return a type which the
;;; function checks LVAR for.
#!-sb-fluid (declaim (inline lvar-externally-checkable-type))
\f
;;;; local call optimization
-;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
-;;; the leaf type is a function type, then just leave it alone, since
-;;; TYPE is never going to be more specific than that (and
-;;; TYPE-INTERSECTION would choke.)
+;;; Propagate TYPE to LEAF and its REFS, marking things changed.
+;;;
+;;; If the leaf type is a function type, then just leave it alone, since TYPE
+;;; is never going to be more specific than that (and TYPE-INTERSECTION would
+;;; choke.)
+;;;
+;;; Also, if the type is one requiring special care don't touch it if the leaf
+;;; has multiple references -- otherwise LVAR-CONSERVATIVE-TYPE is screwed.
(defun propagate-to-refs (leaf type)
(declare (type leaf leaf) (type ctype type))
- (let ((var-type (leaf-type leaf)))
- (unless (fun-type-p var-type)
+ (let ((var-type (leaf-type leaf))
+ (refs (leaf-refs leaf)))
+ (unless (or (fun-type-p var-type)
+ (and (cdr refs)
+ (eq :declared (leaf-where-from leaf))
+ (type-needs-conservation-p var-type)))
(let ((int (type-approx-intersection2 var-type type)))
(when (type/= int var-type)
(setf (leaf-type leaf) int)
(let ((s-int (make-single-value-type int)))
- (dolist (ref (leaf-refs leaf))
+ (dolist (ref refs)
(derive-node-type ref s-int)
;; KLUDGE: LET var substitution
(let* ((lvar (node-lvar ref)))
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