X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcompiler%2Fconstraint.lisp;h=cd9f9f7e84fe777e686835a3d6da97cde0f66e9d;hb=12b1dae1a1ed90c6ffe4d958f1281c1c04a8e89b;hp=fea3f166033acf0687bc44af0d326b9b0c3c2907;hpb=17794352c2ef078a1fc3cdd306f17f7328edf40b;p=sbcl.git diff --git a/src/compiler/constraint.lisp b/src/compiler/constraint.lisp index fea3f16..cd9f9f7 100644 --- a/src/compiler/constraint.lisp +++ b/src/compiler/constraint.lisp @@ -16,6 +16,12 @@ ;;; -- documentation ;;; ;;; -- MV-BIND, :ASSIGNMENT +;;; +;;; Note: The functions in this file that accept constraint sets are +;;; actually receiving the constraint sets associated with nodes, +;;; blocks, and lambda-vars. It might be make CP easier to understand +;;; and work on if these functions traded in nodes, blocks, and +;;; lambda-vars directly. ;;; Problems: ;;; @@ -37,20 +43,22 @@ ;;; 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): is does not understand that this +;;; fail to infer (< I FIXNUM): it does not understand that this ;;; constraint follows from (TYPEP I (INTEGER 0 0)). -;;; BUGS: -;;; -;;; -- this code does not check whether SET appears between REF and a -;;; test (bug 233b) - (in-package "SB!C") +;;; *CONSTRAINT-UNIVERSE* gets bound in IR1-PHASES to a fresh, +;;; zero-length, non-zero-total-size vector-with-fill-pointer. +(declaim (type (and vector (not simple-vector)) *constraint-universe*)) +(defvar *constraint-universe*) + +(deftype constraint-y () '(or ctype lvar lambda-var constant)) + (defstruct (constraint - (:include sset-element) - (:constructor make-constraint (number kind x y not-p)) - (:copier nil)) + (:include sset-element) + (:constructor make-constraint (number kind x y not-p)) + (:copier nil)) ;; the kind of constraint we have: ;; ;; TYPEP @@ -62,54 +70,469 @@ ;; 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)) + (y nil :type constraint-y) ;; If true, negates the sense of the constraint, so the relation ;; does *not* hold. (not-p nil :type boolean)) + +;;; Historically, CMUCL and SBCL have used a sparse set implementation +;;; for which most operations are O(n) (see sset.lisp), but at the +;;; cost of at least a full word of pointer for each constraint set +;;; element. Using bit-vectors instead of pointer structures saves a +;;; lot of space and thus GC time (particularly on 64-bit machines), +;;; and saves time on copy, union, intersection, and difference +;;; operations; but makes iteration slower. Circa September 2008, +;;; switching to bit-vectors gave a modest (5-10%) improvement in real +;;; compile time for most Lisp systems, and as much as 20-30% for some +;;; particularly CP-dependent systems. + +;;; It's bad to leave commented code in files, but if some clever +;;; person comes along and makes SSETs better than bit-vectors as sets +;;; for constraint propagation, or if bit-vectors on some XC host +;;; really lose compared to SSETs, here's the conset API as a wrapper +;;; around SSETs: +#+nil +(progn + (deftype conset () 'sset) + (declaim (ftype (sfunction (conset) boolean) conset-empty)) + (declaim (ftype (sfunction (conset) conset) copy-conset)) + (declaim (ftype (sfunction (constraint conset) boolean) conset-member)) + (declaim (ftype (sfunction (constraint conset) boolean) conset-adjoin)) + (declaim (ftype (sfunction (conset conset) boolean) conset=)) + (declaim (ftype (sfunction (conset conset) (values)) conset-union)) + (declaim (ftype (sfunction (conset conset) (values)) conset-intersection)) + (declaim (ftype (sfunction (conset conset) (values)) conset-difference)) + (defun make-conset () (make-sset)) + (defmacro do-conset-elements ((constraint conset &optional result) &body body) + `(do-sset-elements (,constraint ,conset ,result) ,@body)) + (defmacro do-conset-intersection + ((constraint conset1 conset2 &optional result) &body body) + `(do-conset-elements (,constraint ,conset1 ,result) + (when (conset-member ,constraint ,conset2) + ,@body))) + (defun conset-empty (conset) (sset-empty conset)) + (defun copy-conset (conset) (copy-sset conset)) + (defun conset-member (constraint conset) (sset-member constraint conset)) + (defun conset-adjoin (constraint conset) (sset-adjoin constraint conset)) + (defun conset= (conset1 conset2) (sset= conset1 conset2)) + ;; Note: CP doesn't ever care whether union, intersection, and + ;; difference change the first set. (This is an important degree of + ;; freedom, since some ways of implementing sets lose a great deal + ;; when these operations are required to track changes.) + (defun conset-union (conset1 conset2) + (sset-union conset1 conset2) (values)) + (defun conset-intersection (conset1 conset2) + (sset-intersection conset1 conset2) (values)) + (defun conset-difference (conset1 conset2) + (sset-difference conset1 conset2) (values))) + +(locally + ;; This is performance critical for the compiler, and benefits + ;; from the following declarations. Probably you'll want to + ;; disable these declarations when debugging consets. + (declare #-sb-xc-host (optimize (speed 3) (safety 0) (space 0))) + (declaim (inline %constraint-number)) + (defun %constraint-number (constraint) + (sset-element-number constraint)) + (defstruct (conset + (:constructor make-conset ()) + (:copier %copy-conset)) + (vector (make-array + ;; FIXME: make POWER-OF-TWO-CEILING available earlier? + (ash 1 (integer-length (1- (length *constraint-universe*)))) + :element-type 'bit :initial-element 0) + :type simple-bit-vector) + ;; Bit-vectors win over lightweight hashes for copy, union, + ;; intersection, difference, but lose for iteration if you iterate + ;; over the whole vector. Tracking extrema helps a bit. + (min 0 :type fixnum) + (max 0 :type fixnum)) + + (defun conset-empty (conset) + (or (= (conset-min conset) (conset-max conset)) + (not (find 1 (conset-vector conset) + :start (conset-min conset) + ;; the :end argument can be commented out when + ;; bootstrapping on a < 1.0.9 SBCL errors out with + ;; a full call to DATA-VECTOR-REF-WITH-OFFSET. + :end (conset-max conset))))) + + (defun copy-conset (conset) + (let ((ret (%copy-conset conset))) + (setf (conset-vector ret) (copy-seq (conset-vector conset))) + ret)) -(defvar *constraint-number*) + (defun %conset-grow (conset new-size) + (declare (type index new-size)) + (setf (conset-vector conset) + (replace (the simple-bit-vector + (make-array + (ash 1 (integer-length (1- new-size))) + :element-type 'bit + :initial-element 0)) + (the simple-bit-vector + (conset-vector conset))))) + + (declaim (inline conset-grow)) + (defun conset-grow (conset new-size) + (declare (type index new-size)) + (when (< (length (conset-vector conset)) new-size) + (%conset-grow conset new-size)) + (values)) + + (defun conset-member (constraint conset) + (let ((number (%constraint-number constraint)) + (vector (conset-vector conset))) + (when (< number (length vector)) + (plusp (sbit vector number))))) + + (defun conset-adjoin (constraint conset) + (let ((number (%constraint-number constraint))) + (conset-grow conset (1+ number)) + (setf (sbit (conset-vector conset) number) 1) + (setf (conset-min conset) (min number (conset-min conset))) + (when (>= number (conset-max conset)) + (setf (conset-max conset) (1+ number)))) + conset) + + (defun conset= (conset1 conset2) + (let* ((vector1 (conset-vector conset1)) + (vector2 (conset-vector conset2)) + (length1 (length vector1)) + (length2 (length vector2))) + (if (= length1 length2) + ;; When the lengths are the same, we can rely on EQUAL being + ;; nicely optimized on bit-vectors. + (equal vector1 vector2) + (multiple-value-bind (shorter longer) + (if (< length1 length2) + (values vector1 vector2) + (values vector2 vector1)) + ;; FIXME: make MISMATCH fast on bit-vectors. + (dotimes (index (length shorter)) + (when (/= (sbit vector1 index) (sbit vector2 index)) + (return-from conset= nil))) + (if (find 1 longer :start (length shorter)) + nil + t))))) + + (macrolet + ((defconsetop (name bit-op) + `(defun ,name (conset-1 conset-2) + (declare (optimize (speed 3) (safety 0))) + (let* ((size-1 (length (conset-vector conset-1))) + (size-2 (length (conset-vector conset-2))) + (new-size (max size-1 size-2))) + (conset-grow conset-1 new-size) + (conset-grow conset-2 new-size)) + (let ((vector1 (conset-vector conset-1)) + (vector2 (conset-vector conset-2))) + (declare (simple-bit-vector vector1 vector2)) + (setf (conset-vector conset-1) (,bit-op vector1 vector2 t)) + ;; Update the extrema. + ,(ecase name + ((conset-union) + `(setf (conset-min conset-1) + (min (conset-min conset-1) + (conset-min conset-2)) + (conset-max conset-1) + (max (conset-max conset-1) + (conset-max conset-2)))) + ((conset-intersection) + `(let ((start (max (conset-min conset-1) + (conset-min conset-2))) + (end (min (conset-max conset-1) + (conset-max conset-2)))) + (setf (conset-min conset-1) + (if (> start end) + 0 + (or (position 1 (conset-vector conset-1) + :start start :end end) + 0)) + (conset-max conset-1) + (if (> start end) + 0 + (let ((position + (position + 1 (conset-vector conset-1) + :start start :end end :from-end t))) + (if position + (1+ position) + 0)))))) + ((conset-difference) + `(setf (conset-min conset-1) + (or (position 1 (conset-vector conset-1) + :start (conset-min conset-1) + :end (conset-max conset-1)) + 0) + (conset-max conset-1) + (let ((position + (position + 1 (conset-vector conset-1) + :start (conset-min conset-1) + :end (conset-max conset-1) + :from-end t))) + (if position + (1+ position) + 0)))))) + (values)))) + (defconsetop conset-union bit-ior) + (defconsetop conset-intersection bit-and) + (defconsetop conset-difference bit-andc2))) + +;;; Constraints are hash-consed. Unfortunately, types aren't, so we have +;;; to over-approximate and then linear search through the potential hits. +;;; LVARs can only be found in EQL (not-p = NIL) constraints, while constant +;;; and lambda-vars can only be found in EQL constraints. +(defun find-constraint (kind x y not-p) + (declare (type lambda-var x) (type constraint-y y) (type boolean not-p)) + (etypecase y + (ctype + (awhen (lambda-var-ctype-constraints x) + (dolist (con (gethash (sb!kernel::type-class-info y) it) nil) + (when (and (eq (constraint-kind con) kind) + (eq (constraint-not-p con) not-p) + (type= (constraint-y con) y)) + (return-from find-constraint con))) + nil)) + (lvar + (awhen (lambda-var-eq-constraints x) + (gethash y it))) + ((or constant lambda-var) + (awhen (lambda-var-eq-constraints x) + (let ((cache (gethash y it))) + (declare (type list cache)) + (if not-p (cdr cache) (car cache))))))) + +;;; The most common operations on consets are iterating through the constraints +;;; that are related to a certain variable in a given conset. Storing the +;;; constraints related to each variable in vectors allows us to easily iterate +;;; through the intersection of such constraints and the constraints in a conset. +;;; +;;; EQL-var constraints assert that two lambda-vars are EQL. +;;; Private constraints assert that a lambda-var is EQL or not EQL to a constant. +;;; Inheritable constraints are constraints that may be propagated to EQL +;;; lambda-vars (along with EQL-var constraints). +;;; +;;; Lambda-var -- lvar EQL constraints only serve one purpose: remember whether +;;; an lvar is (only) written to by a ref to that lambda-var, and aren't ever +;;; propagated. +;;; +;;; Finally, the lambda-var conset is only used to track the whole set of +;;; constraints associated with a given lambda-var, and thus easily delete +;;; such constraints from a conset. +(defun register-constraint (x con y) + (declare (type lambda-var x) (type constraint con) (type constraint-y y)) + (conset-adjoin con (lambda-var-constraints x)) + (macrolet ((ensuref (place default) + `(or ,place (setf ,place ,default))) + (ensure-hash (place) + `(ensuref ,place (make-hash-table))) + (ensure-vec (place) + `(ensuref ,place (make-array 8 :adjustable t :fill-pointer 0)))) + (etypecase y + (ctype + (let ((index (ensure-hash (lambda-var-ctype-constraints x))) + (vec (ensure-vec (lambda-var-inheritable-constraints x)))) + (push con (gethash (sb!kernel::type-class-info y) index)) + (vector-push-extend con vec))) + (lvar + (let ((index (ensure-hash (lambda-var-eq-constraints x)))) + (setf (gethash y index) con))) + ((or constant lambda-var) + (let* ((index (ensure-hash (lambda-var-eq-constraints x))) + (cons (ensuref (gethash y index) (list nil)))) + (if (constraint-not-p con) + (setf (cdr cons) con) + (setf (car cons) con))) + (typecase y + (constant + (let ((vec (ensure-vec (lambda-var-private-constraints x)))) + (vector-push-extend con vec))) + (lambda-var + (let ((vec (if (constraint-not-p con) + (ensure-vec (lambda-var-inheritable-constraints x)) + (ensure-vec (lambda-var-eql-var-constraints x))))) + (vector-push-extend con vec))))))) + nil) ;;; 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))))) - (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))) +(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 (length *constraint-universe*) + kind x y not-p))) + (vector-push-extend new *constraint-universe* + (1+ (length *constraint-universe*))) + (register-constraint x new y) + (when (lambda-var-p y) + (register-constraint y new x)) + new))) + +;;; Actual conset interface +;;; +;;; Constraint propagation needs to iterate over the set of lambda-vars known to +;;; be EQL to a given variable (including itself), via DO-EQL-VARS. +;;; +;;; It also has to iterate through constraints that are inherited by EQL variables +;;; (DO-INHERITABLE-CONSTRAINTS), and through constraints used by +;;; CONSTRAIN-REF-TYPE (to derive the type of a REF to a lambda-var). +;;; +;;; Consets must keep track of which lvars are EQL to a given lambda-var (result +;;; from a REF to the lambda-var): CONSET-LVAR-LAMBDA-VAR-EQL-P and +;;; CONSET-ADD-LVAR-LAMBDA-VAR-EQL. This, as all other constraints, must of +;;; course be cleared when a lambda-var's constraints are dropped because of +;;; assignment. +;;; +;;; Consets must be able to add constraints to a given lambda-var +;;; (CONSET-ADD-CONSTRAINT), and to the set of variables EQL to a given +;;; lambda-var (CONSET-ADD-CONSTRAINT-TO-EQL). +;;; +;;; When a lambda-var is assigned to, all the constraints involving that variable +;;; must be dropped: constraint propagation is flow-sensitive, so the constraints +;;; relate to the variable at a given range of program point. In such cases, +;;; constraint propagation calls CONSET-CLEAR-LAMBDA-VAR. +;;; +;;; Finally, one of the main strengths of constraint propagation in SBCL is the +;;; tracking of EQL variables to help constraint propagation. When two variables +;;; are known to be EQL (e.g. after a branch), ADD-EQL-VAR-VAR-CONSTRAINT is +;;; called to add the EQL constraint, but also have each equality class inherit +;;; the other's (inheritable) constraints. +;;; +;;; On top of that, we have the usual bulk set operations: intersection, copy, +;;; equality or emptiness testing. There's also union, but that's only an +;;; optimisation to avoid useless copies in ADD-TEST-CONSTRAINTS and +;;; FIND-BLOCK-TYPE-CONSTRAINTS. +(defmacro do-conset-constraints-intersection ((symbol (conset constraints) &optional result) + &body body) + (let ((min (gensym "MIN")) + (max (gensym "MAX"))) + (once-only ((conset conset) + (constraints constraints)) + `(flet ((body (,symbol) + (declare (type constraint ,symbol)) + ,@body)) + (when ,constraints + (let ((,min (conset-min ,conset)) + (,max (conset-max ,conset))) + (declare (optimize speed)) + (map nil (lambda (constraint) + (declare (type constraint constraint)) + (let ((number (constraint-number constraint))) + (when (and (<= ,min number) + (< number ,max) + (conset-member constraint ,conset)) + (body constraint)))) + ,constraints))) + ,result)))) + +(defmacro do-eql-vars ((symbol (var constraints) &optional result) &body body) + (once-only ((var var) + (constraints constraints)) + `(flet ((body-fun (,symbol) + ,@body)) + (body-fun ,var) + (do-conset-constraints-intersection + (con (,constraints (lambda-var-eql-var-constraints ,var)) ,result) + (let ((x (constraint-x con)) + (y (constraint-y con))) + (body-fun (if (eq ,var x) y x))))))) + +(defmacro do-inheritable-constraints ((symbol (conset variable) &optional result) + &body body) + (once-only ((conset conset) + (variable variable)) + `(block nil + (flet ((body-fun (,symbol) + ,@body)) + (do-conset-constraints-intersection + (con (,conset (lambda-var-inheritable-constraints ,variable))) + (body-fun con)) + (do-conset-constraints-intersection + (con (,conset (lambda-var-eql-var-constraints ,variable)) ,result) + (body-fun con)))))) + +(defmacro do-propagatable-constraints ((symbol (conset variable) &optional result) + &body body) + (once-only ((conset conset) + (variable variable)) + `(block nil + (flet ((body-fun (,symbol) + ,@body)) + (do-conset-constraints-intersection + (con (,conset (lambda-var-private-constraints ,variable))) + (body-fun con)) + (do-conset-constraints-intersection + (con (,conset (lambda-var-eql-var-constraints ,variable))) + (body-fun con)) + (do-conset-constraints-intersection + (con (,conset (lambda-var-inheritable-constraints ,variable)) ,result) + (body-fun con)))))) + +(declaim (inline conset-lvar-lambda-var-eql-p conset-add-lvar-lambda-var-eql)) +(defun conset-lvar-lambda-var-eql-p (conset lvar lambda-var) + (let ((constraint (find-constraint 'eql lambda-var lvar nil))) + (and constraint + (conset-member constraint conset)))) + +(defun conset-add-lvar-lambda-var-eql (conset lvar lambda-var) + (let ((constraint (find-or-create-constraint 'eql lambda-var lvar nil))) + (conset-adjoin constraint conset))) + +(declaim (inline conset-add-constraint conset-add-constraint-to-eql)) +(defun conset-add-constraint (conset kind x y not-p) + (declare (type conset conset) + (type lambda-var x)) + (conset-adjoin (find-or-create-constraint kind x y not-p) + conset)) + +(defun conset-add-constraint-to-eql (conset kind x y not-p &optional (target conset)) + (declare (type conset target conset) + (type lambda-var x)) + (do-eql-vars (x (x conset)) + (conset-add-constraint target kind x y not-p))) + +(declaim (inline conset-clear-lambda-var)) +(defun conset-clear-lambda-var (conset var) + (conset-difference conset (lambda-var-constraints var))) +;;; Copy all CONSTRAINTS involving FROM-VAR - except the (EQL VAR +;;; LVAR) ones - to all of the variables in the VARS list. +(defun inherit-constraints (vars from-var constraints target) + (do-inheritable-constraints (con (constraints from-var)) + (let ((eq-x (eq from-var (constraint-x con))) + (eq-y (eq from-var (constraint-y con)))) + (dolist (var vars) + (conset-add-constraint target + (constraint-kind con) + (if eq-x var (constraint-x con)) + (if eq-y var (constraint-y con)) + (constraint-not-p con)))))) + +;; 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 ((constraint (find-or-create-constraint 'eql var1 var2 nil))) + (unless (conset-member constraint target) + (conset-adjoin constraint target) + (collect ((eql1) (eql2)) + (do-eql-vars (var1 (var1 constraints)) + (eql1 var1)) + (do-eql-vars (var2 (var2 constraints)) + (eql2 var2)) + (inherit-constraints (eql1) var2 constraints target) + (inherit-constraints (eql2) var1 constraints target)) + t))) + ;;; 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. #!-sb-fluid (declaim (inline ok-ref-lambda-var)) @@ -117,116 +540,193 @@ (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)))) - +;;; 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))) + (and lambda-var + (conset-lvar-lambda-var-eql-p constraints lvar lambda-var) + lambda-var))) + ((cast-p use) + (ok-lvar-lambda-var (cast-value use) constraints))))) ;;;; Searching constraints -;;; 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)))) +;;; Add the indicated test constraint to TARGET. +(defun precise-add-test-constraint (fun x y not-p constraints target) + (if (and (eq 'eql fun) (lambda-var-p y) (not not-p)) + (add-eql-var-var-constraint x y constraints target) + (conset-add-constraint-to-eql constraints fun x y not-p target)) (values)) +(defun add-test-constraint (quick-p fun x y not-p constraints target) + (cond (quick-p + (conset-add-constraint target fun x y not-p)) + (t + (precise-add-test-constraint fun x y not-p constraints target)))) ;;; Add complementary constraints to the consequent and alternative ;;; blocks of IF. We do nothing if X is NIL. -(defun add-complement-constraints (if fun x y not-p) - (when (and x - ;; 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. - (not (eq (if-consequent if) - (if-alternative if)))) - (add-test-constraint (if-consequent if) fun x y not-p) - (add-test-constraint (if-alternative if) fun x y (not not-p))) +(declaim (inline precise-add-test-constraint quick-add-complement-constraints)) +(defun precise-add-complement-constraints (fun x y not-p constraints + consequent-constraints + alternative-constraints) + (when x + (precise-add-test-constraint fun x y not-p constraints + consequent-constraints) + (precise-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) - (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 - (unless (eq (combination-kind use) - :error) - (let ((name (continuation-fun-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))))))))) +(defun quick-add-complement-constraints (fun x y not-p + consequent-constraints + alternative-constraints) + (when x + (conset-add-constraint consequent-constraints fun x y not-p) + (conset-add-constraint alternative-constraints fun x y (not not-p))) (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))))) +(defun add-complement-constraints (quick-p fun x y not-p constraints + consequent-constraints + alternative-constraints) + (if quick-p + (quick-add-complement-constraints fun x y not-p + consequent-constraints + alternative-constraints) + (precise-add-complement-constraints fun x y not-p constraints + consequent-constraints + alternative-constraints))) - (setf (block-test-modified block) nil) - (values)) +(defun add-combination-test-constraints (use constraints + consequent-constraints + alternative-constraints + quick-p) + (flet ((add (fun x y not-p) + (add-complement-constraints quick-p + fun x y not-p + constraints + consequent-constraints + alternative-constraints)) + (prop (triples target) + (map nil (lambda (constraint) + (destructuring-bind (kind x y &optional not-p) + constraint + (when (and kind x y) + (add-test-constraint quick-p + kind x y + not-p constraints + target)))) + triples))) + (when (eq (combination-kind use) :known) + (binding* ((info (combination-fun-info use) :exit-if-null) + (propagate (fun-info-constraint-propagate-if + info) + :exit-if-null)) + (multiple-value-bind (lvar type if else) + (funcall propagate use constraints) + (prop if consequent-constraints) + (prop else alternative-constraints) + (when (and lvar type) + (add 'typep (ok-lvar-lambda-var lvar constraints) + type nil) + (return-from add-combination-test-constraints))))) + (let* ((name (lvar-fun-name + (basic-combination-fun use))) + (args (basic-combination-args use)) + (ptype (gethash name *backend-predicate-types*))) + (when ptype + (add 'typep (ok-lvar-lambda-var (first args) + constraints) + ptype nil))))) + +;;; Add test constraints to the consequent and alternative blocks of +;;; the test represented by USE. +(defun add-test-constraints (use if constraints) + (declare (type node use) (type cif if)) + ;; 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-conset)) + (alternative-constraints (make-conset)) + (quick-p (policy if (> compilation-speed speed)))) + (macrolet ((add (fun x y not-p) + `(add-complement-constraints quick-p + ,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 + (let ((*compiler-error-context* use)) + (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 + ;; comparison 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 quick-p + 'typep var2 (lvar-type arg1) + nil constraints + consequent-constraints))) + (var2 + (add 'eql var1 var2 nil)) + ((constant-lvar-p arg2) + (add 'eql var1 + (find-constant (lvar-value arg2)) + nil)) + (t + (add-test-constraint quick-p + '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 + (add-combination-test-constraints use constraints + consequent-constraints + alternative-constraints + quick-p)))))))) + (values consequent-constraints alternative-constraints)))) ;;;; Applying constraints @@ -248,21 +748,21 @@ (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)))) + (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))))) + (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 - (modified-numeric-type x :low new-bound) - (modified-numeric-type x :high new-bound))))) + (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) @@ -272,268 +772,306 @@ (eq (numeric-type-complexp x) :real))) ;;; Exactly the same as CONSTRAIN-INTEGER-TYPE, but for float numbers. +;;; +;;; In contrast to the integer version, here the input types can have +;;; open bounds in addition to closed ones and we don't increment or +;;; decrement a bound to honor OR-EQUAL being NIL but put an open bound +;;; into the result instead, if appropriate. (defun constrain-float-type (x y greater or-equal) (declare (type numeric-type x y)) (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.) + #+sb-xc-host ; (See CROSS-FLOAT-INFINITY-KLUDGE.) x - #-sb-xc-host ; (See CROSS-FLOAT-INFINITY-KLUDGE.) + #-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 (type-bound-number x) (type-bound-number 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 (type-bound-number x) (type-bound-number 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)))))) + (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) + ((= (type-bound-number x) (type-bound-number ref)) + ;; X is tighter if X is an open bound and REF is not + (and (consp x) (not (consp ref)))) + (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))))) + (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 - (modified-numeric-type x :low new-bound) - (modified-numeric-type x :high new-bound))))) + (modified-numeric-type x :low new-bound) + (modified-numeric-type x :high new-bound))))) + +;;; Return true if LEAF is "visible" from NODE. +(defun leaf-visible-from-node-p (leaf node) + (cond + ((lambda-var-p leaf) + ;; A LAMBDA-VAR is visible iif it is homed in a CLAMBDA that is an + ;; ancestor for NODE. + (let ((leaf-lambda (lambda-var-home leaf))) + (loop for lambda = (node-home-lambda node) + then (lambda-parent lambda) + while lambda + when (eq lambda leaf-lambda) + return t))) + ;; FIXME: Check on FUNCTIONALs (CLAMBDAs and OPTIONAL-DISPATCHes), + ;; not just LAMBDA-VARs. + (t + ;; Assume everything else is globally visible. + t))) ;;; Given the set of CONSTRAINTS for a variable and the current set of ;;; restrictions from flow analysis IN, set the type for REF ;;; accordingly. -(defun constrain-ref-type (ref constraints in) - (declare (type ref ref) (type sset constraints in)) - (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))) - (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-approx-intersection2 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))))) - ((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)) - (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)))))))) - +(defun constrain-ref-type (ref in) + (declare (type ref ref) (type conset in)) + ;; KLUDGE: The NOT-SET and NOT-FPZ here are so that we don't need to + ;; cons up endless union types when propagating large number of EQL + ;; constraints -- eg. from large CASE forms -- instead we just + ;; directly accumulate one XSET, and a set of fp zeroes, which we at + ;; the end turn into a MEMBER-TYPE. + ;; + ;; Since massive symbol cases are an especially atrocious pattern + ;; and the (NOT (MEMBER ...ton of symbols...)) will never turn into + ;; a more useful type, don't propagate their negation except for NIL + ;; unless SPEED > COMPILATION-SPEED. + (let ((res (single-value-type (node-derived-type ref))) + (constrain-symbols (policy ref (> speed compilation-speed))) + (not-set (alloc-xset)) + (not-fpz nil) + (not-res *empty-type*) + (leaf (ref-leaf ref))) + (declare (type lambda-var leaf)) + (flet ((note-not (x) + (if (fp-zero-p x) + (push x not-fpz) + (when (or constrain-symbols (null x) (not (symbolp x))) + (add-to-xset x not-set))))) + (do-propagatable-constraints (con (in leaf)) + (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 + (if (member-type-p other) + (mapc-member-type-members #'note-not other) + (setq not-res (type-union not-res other))) + (setq res (type-approx-intersection2 res other)))) + (eql + (let ((other-type (leaf-type other))) + (if not-p + (when (and (constant-p other) + (member-type-p other-type)) + (note-not (constant-value other))) + (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)) + ;; Don't change to a LEAF not visible here. + (leaf-visible-from-node-p other ref))) + (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)) + (or (xset-member-p nil not-set) + (csubtypep (specifier-type 'null) not-res))) + (setf (node-derived-type ref) *wild-type*) + (change-ref-leaf ref (find-constant t))) + (t + (setf not-res + (type-union not-res (make-member-type :xset not-set :fp-zeroes not-fpz))) + (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) + (conset-add-lvar-lambda-var-eql gen lvar leaf)))) + +;; 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 function) - (:set-preprocessor function)) - sset) +(declaim (ftype (function (cblock conset boolean) + conset) constraint-propagate-in-block)) -(defun constraint-propagate-in-block - (block gen &key ref-preprocessor set-preprocessor) - - (let ((test (block-test-constraint block))) - (when test - (sset-union gen test))) - - (do-nodes (node cont block) +(defun constraint-propagate-in-block (block gen preprocess-refs-p) + (do-nodes (node lvar block) (typecase node (bind (let ((fun (bind-lambda node))) (when (eq (functional-kind fun) :let) - (loop with call = (continuation-dest - (node-cont (first (lambda-refs fun)))) + (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) - ;; if VAR has no SETs, type inference is - ;; fully performed by IR1 optimizer - (lambda-var-sets var)) - do (let* ((type (continuation-type val)) - (con (find-constraint 'typep var type nil))) - (sset-adjoin con gen)))))) + when (and val (lambda-var-constraints var)) + do (let ((type (lvar-type val))) + (unless (eq type *universal-type*) + (conset-add-constraint gen 'typep var type nil))) + (maybe-add-eql-var-var-constraint var val gen))))) (ref - (let ((var (ok-ref-lambda-var node))) - (when var - (when ref-preprocessor - (funcall ref-preprocessor node gen)) - (let ((dest (continuation-dest cont))) - (when (cast-p dest) - (let* ((atype (single-value-type (cast-derived-type dest))) ; FIXME - (con (find-constraint 'typep var atype nil))) - (sset-adjoin con gen))))))) + (when (ok-ref-lambda-var node) + (maybe-add-eql-var-lvar-constraint node gen) + (when preprocess-refs-p + (constrain-ref-type 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 + (unless (eq atype *universal-type*) + (conset-add-constraint-to-eql gen 'typep var atype nil))))))) (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-constraint 'typep var type nil))) - (sset-adjoin con gen)))))) - + (nil (lambda-var-constraints var) :exit-if-null)) + (when (policy node (and (= speed 3) (> speed compilation-speed))) + (let ((type (lambda-var-type var))) + (unless (eql *universal-type* type) + (do-eql-vars (other (var gen)) + (unless (eql other var) + (conset-add-constraint gen 'typep other type nil)))))) + (conset-clear-lambda-var gen var) + (let ((type (single-value-type (node-derived-type node)))) + (unless (eq type *universal-type*) + (conset-add-constraint gen 'typep var type nil))) + (unless (policy node (> compilation-speed speed)) + (maybe-add-eql-var-var-constraint var (set-value node) gen)))) + (combination + (when (eq (combination-kind node) :known) + (binding* ((info (combination-fun-info node) :exit-if-null) + (propagate (fun-info-constraint-propagate info) + :exit-if-null) + (constraints (funcall propagate node gen)) + (register (if (policy node + (> compilation-speed speed)) + #'conset-add-constraint + #'conset-add-constraint-to-eql))) + (map nil (lambda (constraint) + (destructuring-bind (kind x y &optional not-p) + constraint + (when (and kind x y) + (funcall register gen + kind x y + not-p)))) + constraints)))))) gen) -;;; 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 compute-block-out (block) - (declare (type cblock block)) - (let ((in (block-in block)) - (kill (block-kill block)) - (out (copy-sset (block-gen block)))) - (cond ((null kill) - (sset-union out 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 out in kill-set)))) - out)) - -;;; Compute the initial flow analysis sets for BLOCK: -;;; -- Compute IN/OUT sets; if OUT of a predecessor is not yet -;;; computed, assume it to be a universal set (this is only -;;; possible in a loop) -;;; -;;; Return T if we have found a loop. -(defun find-block-type-constraints (block) +(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)))))) + +;;; Starting from IN compute OUT and (consequent/alternative +;;; constraints if the block ends with an IF). Return the list of +;;; successors that may need to be recomputed. +(defun find-block-type-constraints (block final-pass-p) (declare (type cblock block)) - (collect ((kill nil adjoin)) - (let ((gen (constraint-propagate-in-block - block (make-sset) - :set-preprocessor (lambda (var) - (kill var))))) - (setf (block-gen block) gen) - (setf (block-kill block) (kill)) - (setf (block-type-asserted block) nil) - (let* ((n (block-number block)) - (pred (block-pred block)) - (in nil) - (loop-p nil)) - (dolist (b pred) - (cond ((> (block-number b) n) - (if in - (sset-intersection in (block-out b)) - (setq in (copy-sset (block-out b))))) - (t (setq loop-p t)))) - (unless in - (bug "Unreachable code is found or flow graph is not ~ - properly depth-first ordered.")) - (setf (block-in block) in) - (setf (block-out block) (compute-block-out block)) - loop-p)))) - -;;; BLOCK-IN becomes the intersection of the OUT of the predecessors. -;;; Our OUT is: -;;; gen U (in - kill) -;;; -;;; Return True if we have done something. -(defun flow-propagate-constraints (block) - (let* ((pred (block-pred block)) - (in (progn (aver pred) - (let ((res (copy-sset (block-out (first pred))))) - (dolist (b (rest pred)) - (sset-intersection res (block-out b))) - res)))) - (setf (block-in block) in) - (let ((out (compute-block-out block))) - (if (sset= out (block-out block)) - nil - (setf (block-out block) out))))) + (let ((gen (constraint-propagate-in-block + block + (if final-pass-p + (block-in block) + (copy-conset (block-in block))) + final-pass-p))) + (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 ((conset-empty consequent-constraints) + (setf (if-consequent-constraints node) gen) + (setf (if-alternative-constraints node) gen)) + (t + (setf (if-consequent-constraints node) (copy-conset gen)) + (conset-union (if-consequent-constraints node) + consequent-constraints) + (setf (if-alternative-constraints node) gen) + (conset-union (if-alternative-constraints node) + alternative-constraints))) + ;; Has the consequent been changed? + (unless (and old-consequent-constraints + (conset= (if-consequent-constraints node) + old-consequent-constraints)) + (push (if-consequent node) succ)) + ;; Has the alternative been changed? + (unless (and old-alternative-constraints + (conset= (if-alternative-constraints node) + old-alternative-constraints)) + (push (if-alternative node) succ)) + succ) + ;; There is no IF. + (unless (and (block-out block) + (conset= 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)) - (constraint-propagate-in-block - block (block-in block) - :ref-preprocessor (lambda (node cons) - (let* ((var (ref-leaf node)) - (con (lambda-var-constraints var))) - (constrain-ref-type node con cons))))) + (constraint-propagate-in-block block (block-in block) t)) ;;; 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 @@ -543,53 +1081,132 @@ (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-conset))))))) (frob fun) (dolist (let (lambda-lets fun)) - (frob let))))) + (frob let))))) + +;;; Return the constraints that flow from PRED to SUCC. This is +;;; BLOCK-OUT unless PRED ends with an 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)))) -;;; How many blocks does COMPONENT have? -(defun component-n-blocks (component) - (let ((result 0)) - (declare (type index result)) - (do-blocks (block component :both) - (incf result)) - result)) +(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 + (conset-intersection in out) + (setq in (copy-conset out)))))) + (or in (make-conset)))) -(defun constraint-propagate (component &aux (loop-p nil)) +(defun update-block-in (block) + (let ((in (compute-block-in block))) + (cond ((and (block-in block) (conset= 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))) +;;; +;;; 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)) - (init-var-constraints 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)))) - (do-blocks (block component) - (when (block-test-modified block) - (find-test-constraints block))) +(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 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 nil))) + ;; 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 nil))))) + rest-of-blocks)))) + +(defun constraint-propagate (component) + (declare (type component component)) + (init-var-constraints component) (unless (block-out (component-head component)) - (setf (block-out (component-head component)) (make-sset))) - - (do-blocks (block component) - (when (find-block-type-constraints block) - (setq loop-p t))) - - (when loop-p - (let (;; If we have to propagate changes more than this many times, - ;; something is wrong. - (max-n-changes-remaining (component-n-blocks component))) - (declare (type fixnum max-n-changes-remaining)) - (loop (aver (>= max-n-changes-remaining 0)) - (decf max-n-changes-remaining) - (let ((did-something nil)) - (do-blocks (block component) - (when (flow-propagate-constraints block) - (setq did-something t))) - (unless did-something - (return)))))) - - (do-blocks (block component) - (use-result-constraints block)) + (setf (block-out (component-head component)) (make-conset))) + + (dolist (block (find-and-propagate-constraints component)) + (unless (block-delete-p block) + (use-result-constraints block))) (values))