1.0.7.27: SLOT-CLASS cleanups

 * No need for two separate implementations of FIND-SLOT-DEFINITION -- just
   move the one we care about to slots-boot.lisp along with MAKE-SLOT-VECTOR
   (which it is intimately tied up with.) Add comments for posterity.

 * There should be no (SETF CLASS-SLOTS) or (SETF CLASS-DIRECT-SLOTS), so
   :READER, not :ACCESSOR in SLOT-CLASS.

diff --git a/src/pcl/defs.lisp b/src/pcl/defs.lisp
index 9a718ab..e01064e 100644 (file)
--- a/src/pcl/defs.lisp
+++ b/src/pcl/defs.lisp
@@ -657,36 +657,14 @@
 (defclass slot-class (pcl-class)
   ((direct-slots
     :initform ()
-    :accessor class-direct-slots)
+    :reader class-direct-slots)
    (slots
     :initform ()
-    :accessor class-slots)
+    :reader class-slots)
    (slot-vector
     :initform #(nil)
     :reader class-slot-vector)))
 
-;;; Make the slot-vector accessed by the after-fixup FIND-SLOT-DEFINITION.
-;;; The slot vector is a simple-vector containing plists of slot-definitions
-;;; keyd by their names. Slot definitions are put in the position indicated
-;;; by (REM (SXHASH SLOT-NAME) (LENGTH SLOT-VECTOR)).
-;;;
-;;; We make the vector slightly longer then the number of slots both
-;;; to reduce collisions (but we're not too picky, really) and to
-;;; allow FIND-SLOT-DEFINTIONS work on slotless classes without
-;;; needing to check for zero-length vectors.
-(defun make-slot-vector (slots)
-  (let* ((n (+ (length slots) 2))
-         (vector (make-array n :initial-element nil)))
-    (flet ((add-to-vector (name slot)
-             (setf (svref vector (rem (sxhash name) n))
-                   (list* name slot (svref vector (rem (sxhash name) n))))))
-      (if (eq 'complete *boot-state*)
-         (dolist (slot slots)
-           (add-to-vector (slot-definition-name slot) slot))
-         (dolist (slot slots)
-           (add-to-vector (early-slot-definition-name slot) slot))))
-    vector))
-
 ;;; The class STD-CLASS is an implementation-specific common
 ;;; superclass of the classes STANDARD-CLASS and
 ;;; FUNCALLABLE-STANDARD-CLASS.

diff --git a/src/pcl/fixup.lisp b/src/pcl/fixup.lisp
index b7b4f21..e3d7f0a 100644 (file)
--- a/src/pcl/fixup.lisp
+++ b/src/pcl/fixup.lisp
@@ -35,15 +35,3 @@
   (declare (ignore depth))
   (print-object instance stream))
 
-;;; Access the slot-vector created by MAKE-SLOT-VECTOR.
-(defun find-slot-definition (class slot-name)
-  (declare (symbol slot-name) (inline getf))
-  (let* ((vector (class-slot-vector class))
-         (index (rem (sxhash slot-name) (length vector))))
-    (declare (simple-vector vector) (index index))
-    (do ((plist (svref vector index) (cdr plist)))
-        ((not plist))
-      (let ((key (car plist)))
-        (setf plist (cdr plist))
-        (when (eq key slot-name)
-          (return (car plist)))))))

diff --git a/src/pcl/slots-boot.lisp b/src/pcl/slots-boot.lisp
index 6bef614..752b190 100644 (file)
--- a/src/pcl/slots-boot.lisp
+++ b/src/pcl/slots-boot.lisp
@@ -521,3 +521,59 @@
     (setf (getf (getf initargs 'plist) :slot-name-lists)
           (list (list nil slot-name)))
     initargs))
+\f
+;;;; FINDING SLOT DEFINITIONS
+;;;
+;;; Historical PCL found slot definitions by iterating over
+;;; CLASS-SLOTS, which is O(N) for number of slots, and moreover
+;;; requires a GF call (for SLOT-DEFINITION-NAME) for each slot in
+;;; list up to the desired one.
+;;;
+;;; As of 1.0.7.26 SBCL hashes the effective slot definitions into a
+;;; simple-vector, with bucket chains made out of plists keyed by the
+;;; slot names. This fixes gives O(1) performance, and avoid the GF
+;;; calls.
+;;;
+;;; MAKE-SLOT-VECTOR constructs the hashed vector out of a list of
+;;; effective slot definitions, and FIND-SLOT-DEFINITION knows how to
+;;; look up slots in that vector.
+;;;
+;;; The only bit of cleverness in the implementation is to make the
+;;; vectors fairly tight, but always longer then 0 elements:
+;;;
+;;; -- We don't want to waste huge amounts of space no these vectors,
+;;;    which are mostly required by things like SLOT-VALUE with a
+;;;    variable slot name, so a constant extension over the minimum
+;;;    size seems like a good choise.
+;;;
+;;; -- As long as the vector always has a length > 0
+;;;    FIND-SLOT-DEFINITION doesn't need to handle the rare case of an
+;;;    empty vector separately: it just returns a NIL.
+
+(defun find-slot-definition (class slot-name)
+  (declare (symbol slot-name) (inline getf))
+  (let* ((vector (class-slot-vector class))
+         (index (rem (sxhash slot-name) (length vector))))
+    (declare (simple-vector vector) (index index)
+             (optimize (sb-c::insert-array-bounds-checks 0)))
+    (do ((plist (the list (svref vector index)) (cdr plist)))
+        ((not (consp plist)))
+      (let ((key (car plist)))
+        (setf plist (cdr plist))
+        (when (eq key slot-name)
+          (return (car plist)))))))
+
+(defun make-slot-vector (slots)
+  (let* ((n (+ (length slots) 2))
+         (vector (make-array n :initial-element nil)))
+    (flet ((add-to-vector (name slot)
+             (declare (symbol name)
+                      (optimize (sb-c::insert-array-bounds-checks 0)))
+             (setf (svref vector (rem (sxhash name) n))
+                   (list* name slot (svref vector (rem (sxhash name) n))))))
+      (if (eq 'complete *boot-state*)
+         (dolist (slot slots)
+           (add-to-vector (slot-definition-name slot) slot))
+         (dolist (slot slots)
+           (add-to-vector (early-slot-definition-name slot) slot))))
+    vector))

diff --git a/src/pcl/slots.lisp b/src/pcl/slots.lisp
index 266a085..da5f09d 100644 (file)
--- a/src/pcl/slots.lisp
+++ b/src/pcl/slots.lisp
@@ -75,11 +75,7 @@
          (t
           (error "unrecognized instance type")))))
 \f
-(defun early-find-slot-definition (class slot-name)
-  (dolist (slot (class-slots class) nil)
-    (when (eql slot-name (slot-definition-name slot))
-      (return slot))))
-(setf (fdefinition 'find-slot-definition) #'early-find-slot-definition)
+;;;; SLOT-VALUE, (SETF SLOT-VALUE), SLOT-BOUNDP
 
 (declaim (ftype (sfunction (t symbol) t) slot-value))
 (defun slot-value (object slot-name)

diff --git a/version.lisp-expr b/version.lisp-expr
index 910b093..fb8db34 100644 (file)
--- a/version.lisp-expr
+++ b/version.lisp-expr
@@ -17,4 +17,4 @@
 ;;; checkins which aren't released. (And occasionally for internal
 ;;; versions, especially for internal versions off the main CVS
 ;;; branch, it gets hairier, e.g. "0.pre7.14.flaky4.13".)
-"1.0.7.26"
+"1.0.7.27"