;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
+;;; TODO:
+;;;
+;;; -- documentation
+;;;
+;;; -- MV-BIND, :ASSIGNMENT
+
+;;; Problems:
+;;;
+;;; -- Constraint propagation badly interacts with bottom-up type
+;;; inference. Consider
+;;;
+;;; (defun foo (n &aux (i 42))
+;;; (declare (optimize speed))
+;;; (declare (fixnum n)
+;;; #+nil (type (integer 0) i))
+;;; (tagbody
+;;; (setq i 0)
+;;; :loop
+;;; (when (>= i n) (go :exit))
+;;; (setq i (1+ i))
+;;; (go :loop)
+;;; :exit))
+;;;
+;;; In this case CP cannot even infer that I is of class INTEGER.
+;;;
+;;; -- In the above example if we place the check after SETQ, CP will
+;;; fail to infer (< I FIXNUM): it does not understand that this
+;;; constraint follows from (TYPEP I (INTEGER 0 0)).
+
(in-package "SB!C")
-(file-comment
- "$Header$")
+(deftype constraint-y () '(or ctype lvar lambda-var constant))
(defstruct (constraint
- (:include sset-element)
- (:constructor make-constraint (number kind x y not-p)))
- ;; The kind of constraint we have:
+ (:include sset-element)
+ (:constructor make-constraint (number kind x y not-p))
+ (:copier nil))
+ ;; the kind of constraint we have:
;;
;; TYPEP
- ;; X is a LAMBDA-VAR and Y is a CTYPE. The value of X is
+ ;; X is a LAMBDA-VAR and Y is a CTYPE. The value of X is
;; constrained to be of type Y.
;;
- ;; >, <
- ;; X is a lambda-var and Y is a CTYPE. The relation holds
+ ;; > or <
+ ;; X is a lambda-var and Y is a CTYPE. The relation holds
;; between X and some object of type Y.
;;
;; EQL
- ;; X is a LAMBDA-VAR Y is a LAMBDA-VAR or a CONSTANT. The
- ;; relation is asserted to hold.
+ ;; X is a LAMBDA-VAR and Y is a LVAR, a LAMBDA-VAR or a CONSTANT.
+ ;; The relation is asserted to hold.
(kind nil :type (member typep < > eql))
;; The operands to the relation.
(x nil :type lambda-var)
- (y nil :type (or ctype lambda-var constant))
- ;; If true, negates the sense of the constraint, so the relation
+ (y nil :type constraint-y)
+ ;; If true, negates the sense of the constraint, so the relation
;; does *not* hold.
(not-p nil :type boolean))
(defvar *constraint-number*)
+(declaim (type (integer 0) *constraint-number*))
+
+(defun find-constraint (kind x y not-p)
+ (declare (type lambda-var x) (type constraint-y y) (type boolean not-p))
+ (etypecase y
+ (ctype
+ (do-sset-elements (con (lambda-var-constraints x) nil)
+ (when (and (eq (constraint-kind con) kind)
+ (eq (constraint-not-p con) not-p)
+ (type= (constraint-y con) y))
+ (return con))))
+ ((or lvar constant)
+ (do-sset-elements (con (lambda-var-constraints x) nil)
+ (when (and (eq (constraint-kind con) kind)
+ (eq (constraint-not-p con) not-p)
+ (eq (constraint-y con) y))
+ (return con))))
+ (lambda-var
+ (do-sset-elements (con (lambda-var-constraints x) nil)
+ (when (and (eq (constraint-kind con) kind)
+ (eq (constraint-not-p con) not-p)
+ (let ((cx (constraint-x con)))
+ (eq (if (eq cx x)
+ (constraint-y con)
+ cx)
+ y)))
+ (return con))))))
;;; Return a constraint for the specified arguments. We only create a
;;; new constraint if there isn't already an equivalent old one,
;;; guaranteeing that all equivalent constraints are EQ. This
;;; shouldn't be called on LAMBDA-VARs with no CONSTRAINTS set.
-(defun find-constraint (kind x y not-p)
- (declare (type lambda-var x) (type (or constant lambda-var ctype) y)
- (type boolean not-p))
- (or (etypecase y
- (ctype
- (do-sset-elements (con (lambda-var-constraints x) nil)
- (when (and (eq (constraint-kind con) kind)
- (eq (constraint-not-p con) not-p)
- (type= (constraint-y con) y))
- (return con))))
- (constant
- (do-sset-elements (con (lambda-var-constraints x) nil)
- (when (and (eq (constraint-kind con) kind)
- (eq (constraint-not-p con) not-p)
- (eq (constraint-y con) y))
- (return con))))
- (lambda-var
- (do-sset-elements (con (lambda-var-constraints x) nil)
- (when (and (eq (constraint-kind con) kind)
- (eq (constraint-not-p con) not-p)
- (let ((cx (constraint-x con)))
- (eq (if (eq cx x)
- (constraint-y con)
- cx)
- y)))
- (return con)))))
+(defun find-or-create-constraint (kind x y not-p)
+ (declare (type lambda-var x) (type constraint-y y) (type boolean not-p))
+ (or (find-constraint kind x y not-p)
(let ((new (make-constraint (incf *constraint-number*) kind x y not-p)))
- (sset-adjoin new (lambda-var-constraints x))
- (when (lambda-var-p y)
- (sset-adjoin new (lambda-var-constraints y)))
- new)))
+ (sset-adjoin new (lambda-var-constraints x))
+ (when (lambda-var-p y)
+ (sset-adjoin new (lambda-var-constraints y)))
+ new)))
;;; If REF is to a LAMBDA-VAR with CONSTRAINTs (i.e. we can do flow
;;; analysis on it), then return the LAMBDA-VAR, otherwise NIL.
(declare (type ref ref))
(let ((leaf (ref-leaf ref)))
(when (and (lambda-var-p leaf)
- (lambda-var-constraints leaf))
+ (lambda-var-constraints leaf))
leaf)))
-;;; If CONT's USE is a REF, then return OK-REF-LAMBDA-VAR of the USE,
-;;; otherwise NIL.
-#!-sb-fluid (declaim (inline ok-cont-lambda-var))
-(defun ok-cont-lambda-var (cont)
- (declare (type continuation cont))
- (let ((use (continuation-use cont)))
- (when (ref-p use)
- (ok-ref-lambda-var use))))
-
-;;; Add the indicated test constraint to BLOCK, marking the block as
-;;; having a new assertion when the constriant was not already
-;;; present. We don't add the constraint if the block has multiple
-;;; predecessors, since it only holds on this particular path.
-(defun add-test-constraint (block fun x y not-p)
- (unless (rest (block-pred block))
- (let ((con (find-constraint fun x y not-p))
- (old (or (block-test-constraint block)
- (setf (block-test-constraint block) (make-sset)))))
- (when (sset-adjoin con old)
- (setf (block-type-asserted block) t))))
+;;; See if LVAR's single USE is a REF to a LAMBDA-VAR and they are EQL
+;;; according to CONSTRAINTS. Return LAMBDA-VAR if so.
+(defun ok-lvar-lambda-var (lvar constraints)
+ (declare (type lvar lvar))
+ (let ((use (lvar-uses lvar)))
+ (cond ((ref-p use)
+ (let ((lambda-var (ok-ref-lambda-var use)))
+ (when lambda-var
+ (let ((constraint (find-constraint 'eql lambda-var lvar nil)))
+ (when (and constraint (sset-member constraint constraints))
+ lambda-var)))))
+ ((cast-p use)
+ (ok-lvar-lambda-var (cast-value use) constraints)))))
+
+(defmacro do-eql-vars ((symbol (var constraints) &optional result) &body body)
+ (once-only ((var var))
+ `(let ((,symbol ,var))
+ (flet ((body-fun ()
+ ,@body))
+ (body-fun)
+ (do-sset-elements (con ,constraints ,result)
+ (let ((other (and (eq (constraint-kind con) 'eql)
+ (eq (constraint-not-p con) nil)
+ (cond ((eq ,var (constraint-x con))
+ (constraint-y con))
+ ((eq ,var (constraint-y con))
+ (constraint-x con))
+ (t
+ nil)))))
+ (when other
+ (setq ,symbol other)
+ (when (lambda-var-p ,symbol)
+ (body-fun)))))))))
+
+;;;; Searching constraints
+
+;;; Add the indicated test constraint to BLOCK. We don't add the
+;;; constraint if the block has multiple predecessors, since it only
+;;; holds on this particular path.
+(defun add-test-constraint (fun x y not-p constraints target)
+ (cond ((and (eq 'eql fun) (lambda-var-p y) (not not-p))
+ (add-eql-var-var-constraint x y constraints target))
+ (t
+ (do-eql-vars (x (x constraints))
+ (let ((con (find-or-create-constraint fun x y not-p)))
+ (sset-adjoin con target)))))
(values))
;;; Add complementary constraints to the consequent and alternative
;;; blocks of IF. We do nothing if X is NIL.
-#!-sb-fluid (declaim (inline add-complement-constraints))
-(defun add-complement-constraints (if fun x y not-p)
+(defun add-complement-constraints (fun x y not-p constraints
+ consequent-constraints
+ alternative-constraints)
(when x
- (add-test-constraint (if-consequent if) fun x y not-p)
- (add-test-constraint (if-alternative if) fun x y (not not-p)))
+ (add-test-constraint fun x y not-p constraints
+ consequent-constraints)
+ (add-test-constraint fun x y (not not-p) constraints
+ alternative-constraints))
(values))
;;; Add test constraints to the consequent and alternative blocks of
;;; the test represented by USE.
-(defun add-test-constraints (use if)
+(defun add-test-constraints (use if constraints)
(declare (type node use) (type cif if))
- (typecase use
- (ref
- (add-complement-constraints if 'typep (ok-ref-lambda-var use)
- (specifier-type 'null) t))
- (combination
- (let ((name (continuation-function-name
- (basic-combination-fun use)))
- (args (basic-combination-args use)))
- (case name
- ((%typep %instance-typep)
- (let ((type (second args)))
- (when (constant-continuation-p type)
- (let ((val (continuation-value type)))
- (add-complement-constraints if 'typep
- (ok-cont-lambda-var (first args))
- (if (ctype-p val)
- val
- (specifier-type val))
- nil)))))
- ((eq eql)
- (let* ((var1 (ok-cont-lambda-var (first args)))
- (arg2 (second args))
- (var2 (ok-cont-lambda-var arg2)))
- (cond ((not var1))
- (var2
- (add-complement-constraints if 'eql var1 var2 nil))
- ((constant-continuation-p arg2)
- (add-complement-constraints if 'eql var1
- (ref-leaf
- (continuation-use arg2))
- nil)))))
- ((< >)
- (let* ((arg1 (first args))
- (var1 (ok-cont-lambda-var arg1))
- (arg2 (second args))
- (var2 (ok-cont-lambda-var arg2)))
- (when var1
- (add-complement-constraints if name var1 (continuation-type arg2)
- nil))
- (when var2
- (add-complement-constraints if (if (eq name '<) '> '<)
- var2 (continuation-type arg1)
- nil))))
- (t
- (let ((ptype (gethash name *backend-predicate-types*)))
- (when ptype
- (add-complement-constraints if 'typep
- (ok-cont-lambda-var (first args))
- ptype nil))))))))
- (values))
-
-;;; Set the TEST-CONSTRAINT in the successors of BLOCK according to
-;;; the condition it tests.
-(defun find-test-constraints (block)
- (declare (type cblock block))
- (let ((last (block-last block)))
- (when (if-p last)
- (let ((use (continuation-use (if-test last))))
- (when use
- (add-test-constraints use last)))))
-
- (setf (block-test-modified block) nil)
- (values))
-
-;;; Compute the initial flow analysis sets for BLOCK:
-;;; -- For any lambda-var ref with a type check, add that constraint.
-;;; -- For any lambda-var set, delete all constraints on that var, and add
-;;; those constraints to the set nuked by this block.
-(defun find-block-type-constraints (block)
- (declare (type cblock block))
- (let ((gen (make-sset)))
- (collect ((kill nil adjoin))
-
- (let ((test (block-test-constraint block)))
- (when test
- (sset-union gen test)))
-
- (do-nodes (node cont block)
- (typecase node
- (ref
- (when (continuation-type-check cont)
- (let ((var (ok-ref-lambda-var node)))
- (when var
- (let* ((atype (continuation-derived-type cont))
- (con (find-constraint 'typep var atype nil)))
- (sset-adjoin con gen))))))
- (cset
- (let ((var (set-var node)))
- (when (lambda-var-p var)
- (kill var)
- (let ((cons (lambda-var-constraints var)))
- (when cons
- (sset-difference gen cons))))))))
-
- (setf (block-in block) nil)
- (setf (block-gen block) gen)
- (setf (block-kill block) (kill))
- (setf (block-out block) (copy-sset gen))
- (setf (block-type-asserted block) nil)
- (values))))
+ ;; Note: Even if we do (IF test exp exp) => (PROGN test exp)
+ ;; optimization, the *MAX-OPTIMIZE-ITERATIONS* cutoff means that we
+ ;; can't guarantee that the optimization will be done, so we still
+ ;; need to avoid barfing on this case.
+ (unless (eq (if-consequent if) (if-alternative if))
+ (let ((consequent-constraints (make-sset))
+ (alternative-constraints (make-sset)))
+ (macrolet ((add (fun x y not-p)
+ `(add-complement-constraints ,fun ,x ,y ,not-p
+ constraints
+ consequent-constraints
+ alternative-constraints)))
+ (typecase use
+ (ref
+ (add 'typep (ok-lvar-lambda-var (ref-lvar use) constraints)
+ (specifier-type 'null) t))
+ (combination
+ (unless (eq (combination-kind use)
+ :error)
+ (let ((name (lvar-fun-name
+ (basic-combination-fun use)))
+ (args (basic-combination-args use)))
+ (case name
+ ((%typep %instance-typep)
+ (let ((type (second args)))
+ (when (constant-lvar-p type)
+ (let ((val (lvar-value type)))
+ (add 'typep
+ (ok-lvar-lambda-var (first args) constraints)
+ (if (ctype-p val)
+ val
+ (specifier-type val))
+ nil)))))
+ ((eq eql)
+ (let* ((arg1 (first args))
+ (var1 (ok-lvar-lambda-var arg1 constraints))
+ (arg2 (second args))
+ (var2 (ok-lvar-lambda-var arg2 constraints)))
+ ;; The code below assumes that the constant is the
+ ;; second argument in case of variable to constant
+ ;; comparision which is sometimes true (see source
+ ;; transformations for EQ, EQL and CHAR=). Fixing
+ ;; that would result in more constant substitutions
+ ;; which is not a universally good thing, thus the
+ ;; unnatural asymmetry of the tests.
+ (cond ((not var1)
+ (when var2
+ (add-test-constraint 'typep var2 (lvar-type arg1)
+ nil constraints
+ consequent-constraints)))
+ (var2
+ (add 'eql var1 var2 nil))
+ ((constant-lvar-p arg2)
+ (add 'eql var1 (ref-leaf (principal-lvar-use arg2))
+ nil))
+ (t
+ (add-test-constraint 'typep var1 (lvar-type arg2)
+ nil constraints
+ consequent-constraints)))))
+ ((< >)
+ (let* ((arg1 (first args))
+ (var1 (ok-lvar-lambda-var arg1 constraints))
+ (arg2 (second args))
+ (var2 (ok-lvar-lambda-var arg2 constraints)))
+ (when var1
+ (add name var1 (lvar-type arg2) nil))
+ (when var2
+ (add (if (eq name '<) '> '<) var2 (lvar-type arg1) nil))))
+ (t
+ (let ((ptype (gethash name *backend-predicate-types*)))
+ (when ptype
+ (add 'typep (ok-lvar-lambda-var (first args) constraints)
+ ptype nil))))))))))
+ (values consequent-constraints alternative-constraints))))
+
+;;;; Applying constraints
;;; Return true if X is an integer NUMERIC-TYPE.
(defun integer-type-p (x)
(defun constrain-integer-type (x y greater or-equal)
(declare (type numeric-type x y))
(flet ((exclude (x)
- (cond ((not x) nil)
- (or-equal x)
- (greater (1+ x))
- (t (1- x))))
- (bound (x)
- (if greater (numeric-type-low x) (numeric-type-high x)))
- (validate (x)
- (if (and (numeric-type-low x) (numeric-type-high x)
- (> (numeric-type-low x) (numeric-type-high x)))
- *empty-type*
- x)))
+ (cond ((not x) nil)
+ (or-equal x)
+ (greater (1+ x))
+ (t (1- x))))
+ (bound (x)
+ (if greater (numeric-type-low x) (numeric-type-high x))))
(let* ((x-bound (bound x))
- (y-bound (exclude (bound y)))
- (new-bound (cond ((not x-bound) y-bound)
- ((not y-bound) x-bound)
- (greater (max x-bound y-bound))
- (t (min x-bound y-bound))))
- (res (copy-numeric-type x)))
+ (y-bound (exclude (bound y)))
+ (new-bound (cond ((not x-bound) y-bound)
+ ((not y-bound) x-bound)
+ (greater (max x-bound y-bound))
+ (t (min x-bound y-bound)))))
(if greater
- (setf (numeric-type-low res) new-bound)
- (setf (numeric-type-high res) new-bound))
- (validate res))))
+ (modified-numeric-type x :low new-bound)
+ (modified-numeric-type x :high new-bound)))))
;;; Return true if X is a float NUMERIC-TYPE.
(defun float-type-p (x)
;;; Exactly the same as CONSTRAIN-INTEGER-TYPE, but for float numbers.
(defun constrain-float-type (x y greater or-equal)
(declare (type numeric-type x y))
- ;; Unless :PROPAGATE-FLOAT-TYPE is in target features, then
- ;; SB!C::BOUND-VALUE (used in the code below) is not defined, so we
- ;; just return X without trying to calculate additional constraints.
- #!-propagate-float-type (declare (ignore y greater or-equal))
- #!-propagate-float-type x
- #!+propagate-float-type
+ (declare (ignorable x y greater or-equal)) ; for CROSS-FLOAT-INFINITY-KLUDGE
+
+ (aver (eql (numeric-type-class x) 'float))
+ (aver (eql (numeric-type-class y) 'float))
+ #+sb-xc-host ; (See CROSS-FLOAT-INFINITY-KLUDGE.)
+ x
+ #-sb-xc-host ; (See CROSS-FLOAT-INFINITY-KLUDGE.)
(labels ((exclude (x)
- (cond ((not x) nil)
- (or-equal x)
- (greater
- (if (consp x)
- (car x)
- x))
- (t
- (if (consp x)
- x
- (list x)))))
- (bound (x)
- (if greater (numeric-type-low x) (numeric-type-high x)))
- (max-lower-bound (x y)
- ;; Both x and y are not null. Find the max.
- (let ((res (max (bound-value x) (bound-value y))))
- ;; An open lower bound is greater than a close
- ;; lower bound because the open bound doesn't
- ;; contain the bound, so choose an open lower
- ;; bound.
- (set-bound res (or (consp x) (consp y)))))
- (min-upper-bound (x y)
- ;; Same as above, but for the min of upper bounds
- ;; Both x and y are not null. Find the min.
- (let ((res (min (bound-value x) (bound-value y))))
- ;; An open upper bound is less than a closed
- ;; upper bound because the open bound doesn't
- ;; contain the bound, so choose an open lower
- ;; bound.
- (set-bound res (or (consp x) (consp y)))))
- (validate (x)
- (let ((x-lo (numeric-type-low x))
- (x-hi (numeric-type-high x)))
- (if (and x-lo x-hi (> (bound-value x-lo) (bound-value x-hi)))
- *empty-type*
- x))))
+ (cond ((not x) nil)
+ (or-equal x)
+ (t
+ (if (consp x)
+ x
+ (list x)))))
+ (bound (x)
+ (if greater (numeric-type-low x) (numeric-type-high x)))
+ (tighter-p (x ref)
+ (cond ((null x) nil)
+ ((null ref) t)
+ ((and or-equal
+ (= (type-bound-number x) (type-bound-number ref)))
+ ;; X is tighter if REF is not an open bound and X is
+ (and (not (consp ref)) (consp x)))
+ (greater
+ (< (type-bound-number ref) (type-bound-number x)))
+ (t
+ (> (type-bound-number ref) (type-bound-number x))))))
(let* ((x-bound (bound x))
- (y-bound (exclude (bound y)))
- (new-bound (cond ((not x-bound)
- y-bound)
- ((not y-bound)
- x-bound)
- (greater
- (max-lower-bound x-bound y-bound))
- (t
- (min-upper-bound x-bound y-bound))))
- (res (copy-numeric-type x)))
+ (y-bound (exclude (bound y)))
+ (new-bound (cond ((not x-bound)
+ y-bound)
+ ((not y-bound)
+ x-bound)
+ ((tighter-p y-bound x-bound)
+ y-bound)
+ (t
+ x-bound))))
(if greater
- (setf (numeric-type-low res) new-bound)
- (setf (numeric-type-high res) new-bound))
- (validate res))))
+ (modified-numeric-type x :low new-bound)
+ (modified-numeric-type x :high new-bound)))))
;;; Given the set of CONSTRAINTS for a variable and the current set of
;;; restrictions from flow analysis IN, set the type for REF
(let ((var-cons (copy-sset constraints)))
(sset-intersection var-cons in)
(let ((res (single-value-type (node-derived-type ref)))
- (not-res *empty-type*)
- (leaf (ref-leaf ref)))
+ (not-res *empty-type*)
+ (leaf (ref-leaf ref)))
(do-sset-elements (con var-cons)
- (let* ((x (constraint-x con))
- (y (constraint-y con))
- (not-p (constraint-not-p con))
- (other (if (eq x leaf) y x))
- (kind (constraint-kind con)))
- (case kind
- (typep
- (if not-p
- (setq not-res (type-union not-res other))
- (setq res (type-intersection res other))))
- (eql
- (let ((other-type (leaf-type other)))
- (if not-p
- (when (and (constant-p other)
- (member-type-p other-type))
- (setq not-res (type-union not-res other-type)))
- (let ((leaf-type (leaf-type leaf)))
- (when (or (constant-p other)
- (and (csubtypep other-type leaf-type)
- (not (type= other-type leaf-type))))
- (change-ref-leaf ref other)
- (when (constant-p other) (return)))))))
- ((< >)
- (cond ((and (integer-type-p res) (integer-type-p y))
- (let ((greater (eq kind '>)))
- (let ((greater (if not-p (not greater) greater)))
- (setq res
- (constrain-integer-type res y greater not-p)))))
- #!+constrain-float-type
- ((and (float-type-p res) (float-type-p y))
- (let ((greater (eq kind '>)))
- (let ((greater (if not-p (not greater) greater)))
- (setq res
- (constrain-float-type res y greater not-p)))))
- )))))
-
- (let* ((cont (node-cont ref))
- (dest (continuation-dest cont)))
- (cond ((and (if-p dest)
- (csubtypep (specifier-type 'null) not-res)
- (eq (continuation-asserted-type cont) *wild-type*))
- (setf (node-derived-type ref) *wild-type*)
- (change-ref-leaf ref (find-constant 't)))
- (t
- (derive-node-type ref (or (type-difference res not-res)
- res)))))))
+ (let* ((x (constraint-x con))
+ (y (constraint-y con))
+ (not-p (constraint-not-p con))
+ (other (if (eq x leaf) y x))
+ (kind (constraint-kind con)))
+ (case kind
+ (typep
+ (if not-p
+ (setq not-res (type-union not-res other))
+ (setq res (type-approx-intersection2 res other))))
+ (eql
+ (unless (lvar-p other)
+ (let ((other-type (leaf-type other)))
+ (if not-p
+ (when (and (constant-p other)
+ (member-type-p other-type))
+ (setq not-res (type-union not-res other-type)))
+ (let ((leaf-type (leaf-type leaf)))
+ (cond
+ ((or (constant-p other)
+ (and (leaf-refs other) ; protect from
+ ; deleted vars
+ (csubtypep other-type leaf-type)
+ (not (type= other-type leaf-type))))
+ (change-ref-leaf ref other)
+ (when (constant-p other) (return)))
+ (t
+ (setq res (type-approx-intersection2
+ res other-type)))))))))
+ ((< >)
+ (cond
+ ((and (integer-type-p res) (integer-type-p y))
+ (let ((greater (eq kind '>)))
+ (let ((greater (if not-p (not greater) greater)))
+ (setq res
+ (constrain-integer-type res y greater not-p)))))
+ ((and (float-type-p res) (float-type-p y))
+ (let ((greater (eq kind '>)))
+ (let ((greater (if not-p (not greater) greater)))
+ (setq res
+ (constrain-float-type res y greater not-p))))))))))
+ (cond ((and (if-p (node-dest ref))
+ (csubtypep (specifier-type 'null) not-res))
+ (setf (node-derived-type ref) *wild-type*)
+ (change-ref-leaf ref (find-constant t)))
+ (t
+ (derive-node-type ref
+ (make-single-value-type
+ (or (type-difference res not-res)
+ res)))
+ (maybe-terminate-block ref nil)))))
(values))
+;;;; Flow analysis
+
+(defun maybe-add-eql-var-lvar-constraint (ref gen)
+ (let ((lvar (ref-lvar ref))
+ (leaf (ref-leaf ref)))
+ (when (and (lambda-var-p leaf) lvar)
+ (sset-adjoin (find-or-create-constraint 'eql leaf lvar nil)
+ gen))))
+
+;;; Copy all CONSTRAINTS involving FROM-VAR to VAR except the (EQL VAR
+;;; LVAR) ones.
+(defun inherit-constraints (var from-var constraints target)
+ (do-sset-elements (con constraints)
+ (let ((eq-x (eq from-var (constraint-x con)))
+ (eq-y (eq from-var (constraint-y con))))
+ ;; Constant substitution is controversial.
+ (unless (constant-p (constraint-y con))
+ (when (or (and eq-x (not (lvar-p (constraint-y con))))
+ eq-y)
+ (sset-adjoin (find-or-create-constraint
+ (constraint-kind con)
+ (if eq-x var (constraint-x con))
+ (if eq-y var (constraint-y con))
+ (constraint-not-p con))
+ target))))))
+
+;; Add an (EQL LAMBDA-VAR LAMBDA-VAR) constraint on VAR1 and VAR2 and
+;; inherit each other's constraints.
+(defun add-eql-var-var-constraint (var1 var2 constraints
+ &optional (target constraints))
+ (let ((con (find-or-create-constraint 'eql var1 var2 nil)))
+ (when (sset-adjoin con target)
+ (do-eql-vars (var2 (var2 constraints))
+ (inherit-constraints var1 var2 constraints target))
+ (do-eql-vars (var1 (var1 constraints))
+ (inherit-constraints var2 var1 constraints target))
+ t)))
+
+;; Add an (EQL LAMBDA-VAR LAMBDA-VAR) constraint on VAR and LVAR's
+;; LAMBDA-VAR if possible.
+(defun maybe-add-eql-var-var-constraint (var lvar constraints
+ &optional (target constraints))
+ (declare (type lambda-var var) (type lvar lvar))
+ (let ((lambda-var (ok-lvar-lambda-var lvar constraints)))
+ (when lambda-var
+ (add-eql-var-var-constraint var lambda-var constraints target))))
+
+;;; Local propagation
+;;; -- [TODO: For any LAMBDA-VAR ref with a type check, add that
+;;; constraint.]
+;;; -- For any LAMBDA-VAR set, delete all constraints on that var; add
+;;; a type constraint based on the new value type.
+(declaim (ftype (function (cblock sset
+ &key (:ref-preprocessor (or null function))
+ (:set-preprocessor (or null function)))
+ sset)
+ constraint-propagate-in-block))
+(defun constraint-propagate-in-block
+ (block gen &key ref-preprocessor set-preprocessor)
+
+ (do-nodes (node lvar block)
+ (typecase node
+ (bind
+ (let ((fun (bind-lambda node)))
+ (when (eq (functional-kind fun) :let)
+ (loop with call = (lvar-dest (node-lvar (first (lambda-refs fun))))
+ for var in (lambda-vars fun)
+ and val in (combination-args call)
+ when (and val (lambda-var-constraints var))
+ do (let* ((type (lvar-type val))
+ (con (find-or-create-constraint 'typep var type
+ nil)))
+ (sset-adjoin con gen))
+ (maybe-add-eql-var-var-constraint var val gen)))))
+ (ref
+ (when (ok-ref-lambda-var node)
+ (maybe-add-eql-var-lvar-constraint node gen)
+ (when ref-preprocessor
+ (funcall ref-preprocessor node gen))))
+ (cast
+ (let ((lvar (cast-value node)))
+ (let ((var (ok-lvar-lambda-var lvar gen)))
+ (when var
+ (let ((atype (single-value-type (cast-derived-type node)))) ;FIXME
+ (do-eql-vars (var (var gen))
+ (let ((con (find-or-create-constraint 'typep var atype nil)))
+ (sset-adjoin con gen))))))))
+ (cset
+ (binding* ((var (set-var node))
+ (nil (lambda-var-p var) :exit-if-null)
+ (cons (lambda-var-constraints var) :exit-if-null))
+ (when set-preprocessor
+ (funcall set-preprocessor var))
+ (sset-difference gen cons)
+ (let* ((type (single-value-type (node-derived-type node)))
+ (con (find-or-create-constraint 'typep var type nil)))
+ (sset-adjoin con gen))
+ (maybe-add-eql-var-var-constraint var (set-value node) gen)))))
+
+ gen)
+
+(defun constraint-propagate-if (block gen)
+ (let ((node (block-last block)))
+ (when (if-p node)
+ (let ((use (lvar-uses (if-test node))))
+ (when (node-p use)
+ (add-test-constraints use node gen))))))
+
+(defun constrain-node (node cons)
+ (let* ((var (ref-leaf node))
+ (con (lambda-var-constraints var)))
+ (constrain-ref-type node con cons)))
+
+;;; Starting from IN compute OUT and (consequent/alternative
+;;; constraints if the block ends with and IF). Return the list of
+;;; successors that may need to be recomputed.
+(defun find-block-type-constraints (block &key final-pass-p)
+ (declare (type cblock block))
+ (let ((gen (constraint-propagate-in-block
+ block
+ (if final-pass-p
+ (block-in block)
+ (copy-sset (block-in block)))
+ :ref-preprocessor (if final-pass-p #'constrain-node nil))))
+ (setf (block-gen block) gen)
+ (multiple-value-bind (consequent-constraints alternative-constraints)
+ (constraint-propagate-if block gen)
+ (if consequent-constraints
+ (let* ((node (block-last block))
+ (old-consequent-constraints (if-consequent-constraints node))
+ (old-alternative-constraints (if-alternative-constraints node))
+ (succ ()))
+ ;; Add the consequent and alternative constraints to GEN.
+ (cond ((sset-empty consequent-constraints)
+ (setf (if-consequent-constraints node) gen)
+ (setf (if-alternative-constraints node) gen))
+ (t
+ (setf (if-consequent-constraints node) (copy-sset gen))
+ (sset-union (if-consequent-constraints node)
+ consequent-constraints)
+ (setf (if-alternative-constraints node) gen)
+ (sset-union (if-alternative-constraints node)
+ alternative-constraints)))
+ ;; Has the consequent been changed?
+ (unless (and old-consequent-constraints
+ (sset= (if-consequent-constraints node)
+ old-consequent-constraints))
+ (push (if-consequent node) succ))
+ ;; Has the alternative been changed?
+ (unless (and old-alternative-constraints
+ (sset= (if-alternative-constraints node)
+ old-alternative-constraints))
+ (push (if-alternative node) succ))
+ succ)
+ ;; There is no IF.
+ (unless (and (block-out block)
+ (sset= gen (block-out block)))
+ (setf (block-out block) gen)
+ (block-succ block))))))
+
;;; Deliver the results of constraint propagation to REFs in BLOCK.
;;; During this pass, we also do local constraint propagation by
-;;; adding in constraints as we seem them during the pass through the
+;;; adding in constraints as we see them during the pass through the
;;; block.
(defun use-result-constraints (block)
(declare (type cblock block))
- (let ((in (block-in block)))
-
- (let ((test (block-test-constraint block)))
- (when test
- (sset-union in test)))
-
- (do-nodes (node cont block)
- (typecase node
- (ref
- (let ((var (ref-leaf node)))
- (when (lambda-var-p var)
- (let ((con (lambda-var-constraints var)))
- (when con
- (constrain-ref-type node con in)
- (when (continuation-type-check cont)
- (sset-adjoin
- (find-constraint 'typep var
- (continuation-asserted-type cont)
- nil)
- in)))))))
- (cset
- (let ((var (set-var node)))
- (when (lambda-var-p var)
- (let ((cons (lambda-var-constraints var)))
- (when cons
- (sset-difference in cons))))))))))
-
-;;; Return true if VAR would have to be closed over if environment
-;;; analysis ran now (i.e. if there are any uses that have a different
-;;; home lambda than VAR's home.)
-(defun closure-var-p (var)
- (declare (type lambda-var var))
- (let ((home (lambda-home (lambda-var-home var))))
- (flet ((frob (l)
- (dolist (node l nil)
- (unless (eq (node-home-lambda node) home)
- (return t)))))
- (or (frob (leaf-refs var))
- (frob (basic-var-sets var))))))
+ (constraint-propagate-in-block block (block-in block)
+ :ref-preprocessor #'constrain-node))
;;; Give an empty constraints set to any var that doesn't have one and
;;; isn't a set closure var. Since a var that we previously rejected
(declare (type component component))
(dolist (fun (component-lambdas component))
(flet ((frob (x)
- (dolist (var (lambda-vars x))
- (unless (lambda-var-constraints var)
- (when (or (null (lambda-var-sets var))
- (not (closure-var-p var)))
- (setf (lambda-var-constraints var) (make-sset)))))))
+ (dolist (var (lambda-vars x))
+ (unless (lambda-var-constraints var)
+ (when (or (null (lambda-var-sets var))
+ (not (closure-var-p var)))
+ (setf (lambda-var-constraints var) (make-sset)))))))
(frob fun)
(dolist (let (lambda-lets fun))
- (frob let)))))
-
-;;; BLOCK-IN becomes the intersection of the OUT of the prececessors.
-;;; Our OUT is:
-;;; out U (in - kill)
+ (frob let)))))
+
+;;; Return the constraints that flow from PRED to SUCC. This is
+;;; BLOCK-OUT unless PRED ends with and IF and test constraints were
+;;; added.
+(defun block-out-for-successor (pred succ)
+ (declare (type cblock pred succ))
+ (let ((last (block-last pred)))
+ (or (when (if-p last)
+ (cond ((eq succ (if-consequent last))
+ (if-consequent-constraints last))
+ ((eq succ (if-alternative last))
+ (if-alternative-constraints last))))
+ (block-out pred))))
+
+(defun compute-block-in (block)
+ (let ((in nil))
+ (dolist (pred (block-pred block))
+ ;; If OUT has not been calculated, assume it to be the universal
+ ;; set.
+ (let ((out (block-out-for-successor pred block)))
+ (when out
+ (if in
+ (sset-intersection in out)
+ (setq in (copy-sset out))))))
+ (or in (make-sset))))
+
+(defun update-block-in (block)
+ (let ((in (compute-block-in block)))
+ (cond ((and (block-in block) (sset= in (block-in block)))
+ nil)
+ (t
+ (setf (block-in block) in)))))
+
+;;; Return two lists: one of blocks that precede all loops and
+;;; therefore require only one constraint propagation pass and the
+;;; rest. This implementation does not find all such blocks.
+;;;
+;;; A more complete implementation would be:
+;;;
+;;; (do-blocks (block component)
+;;; (if (every #'(lambda (pred)
+;;; (or (member pred leading-blocks)
+;;; (eq pred head)))
+;;; (block-pred block))
+;;; (push block leading-blocks)
+;;; (push block rest-of-blocks)))
;;;
-;;; BLOCK-KILL is just a list of the lambda-vars killed, so we must
-;;; compute the kill set when there are any vars killed. We bum this a
-;;; bit by special-casing when only one var is killed, and just using
-;;; that var's constraints as the kill set. This set could possibly be
-;;; precomputed, but it would have to be invalidated whenever any
-;;; constraint is added, which would be a pain.
-(defun flow-propagate-constraints (block)
- (let* ((pred (block-pred block))
- (in (cond (pred
- (let ((res (copy-sset (block-out (first pred)))))
- (dolist (b (rest pred))
- (sset-intersection res (block-out b)))
- res))
- (t
- (when *check-consistency*
- (let ((*compiler-error-context* (block-last block)))
- (compiler-warning
- "*** Unreachable code in constraint ~
- propagation... Bug?")))
- (make-sset))))
- (kill (block-kill block))
- (out (block-out block)))
-
- (setf (block-in block) in)
- (cond ((null kill)
- (sset-union (block-out block) in))
- ((null (rest kill))
- (let ((con (lambda-var-constraints (first kill))))
- (if con
- (sset-union-of-difference out in con)
- (sset-union out in))))
- (t
- (let ((kill-set (make-sset)))
- (dolist (var kill)
- (let ((con (lambda-var-constraints var)))
- (when con
- (sset-union kill-set con))))
- (sset-union-of-difference (block-out block) in kill-set))))))
+;;; Trailing blocks that succeed all loops could be found and handled
+;;; similarly. In practice though, these more complex solutions are
+;;; slightly worse performancewise.
+(defun leading-component-blocks (component)
+ (declare (type component component))
+ (flet ((loopy-p (block)
+ (let ((n (block-number block)))
+ (dolist (pred (block-pred block))
+ (unless (< n (block-number pred))
+ (return t))))))
+ (let ((leading-blocks ())
+ (rest-of-blocks ())
+ (seen-loop-p ()))
+ (do-blocks (block component)
+ (when (and (not seen-loop-p) (loopy-p block))
+ (setq seen-loop-p t))
+ (if seen-loop-p
+ (push block rest-of-blocks)
+ (push block leading-blocks)))
+ (values (nreverse leading-blocks) (nreverse rest-of-blocks)))))
+
+;;; Append OBJ to the end of LIST as if by NCONC but only if it is not
+;;; a member already.
+(defun nconc-new (obj list)
+ (do ((x list (cdr x))
+ (prev nil x))
+ ((endp x) (if prev
+ (progn
+ (setf (cdr prev) (list obj))
+ list)
+ (list obj)))
+ (when (eql (car x) obj)
+ (return-from nconc-new list))))
+
+(defun find-and-propagate-constraints (component)
+ (let ((blocks-to-process ()))
+ (flet ((enqueue (blocks)
+ (dolist (block blocks)
+ (setq blocks-to-process (nconc-new block blocks-to-process)))))
+ (multiple-value-bind (leading-blocks rest-of-blocks)
+ (leading-component-blocks component)
+ ;; Update every block once to account for changes in the
+ ;; IR1. The constraints of the lead blocks cannot be changed
+ ;; after the first pass so we might as well use them and skip
+ ;; USE-RESULT-CONSTRAINTS later.
+ (dolist (block leading-blocks)
+ (setf (block-in block) (compute-block-in block))
+ (find-block-type-constraints block :final-pass-p t))
+ (setq blocks-to-process (copy-list rest-of-blocks))
+ ;; The rest of the blocks.
+ (dolist (block rest-of-blocks)
+ (aver (eq block (pop blocks-to-process)))
+ (setf (block-in block) (compute-block-in block))
+ (enqueue (find-block-type-constraints block)))
+ ;; Propagate constraints
+ (loop for block = (pop blocks-to-process)
+ while block do
+ (unless (eq block (component-tail component))
+ (when (update-block-in block)
+ (enqueue (find-block-type-constraints block)))))
+ rest-of-blocks))))
(defun constraint-propagate (component)
(declare (type component component))
(init-var-constraints component)
- (do-blocks (block component)
- (when (block-test-modified block)
- (find-test-constraints block)))
-
- (do-blocks (block component)
- (cond ((block-type-asserted block)
- (find-block-type-constraints block))
- (t
- (setf (block-in block) nil)
- (setf (block-out block) (copy-sset (block-gen block))))))
-
- (setf (block-out (component-head component)) (make-sset))
+ (unless (block-out (component-head component))
+ (setf (block-out (component-head component)) (make-sset)))
- (let ((did-something nil))
- (loop
- (do-blocks (block component)
- (when (flow-propagate-constraints block)
- (setq did-something t)))
-
- (unless did-something (return))
- (setq did-something nil)))
-
- (do-blocks (block component)
- (use-result-constraints block))
+ (dolist (block (find-and-propagate-constraints component))
+ (unless (block-delete-p block)
+ (use-result-constraints block)))
(values))
-
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