src/pcl/braid.lisp

   1 ;;;; bootstrapping the meta-braid
   2 ;;;;
   3 ;;;; The code in this file takes the early definitions that have been saved
   4 ;;;; up and actually builds those class objects. This work is largely driven
   5 ;;;; off of those class definitions, but the fact that STANDARD-CLASS is the
   6 ;;;; class of all metaclasses in the braid is built into this code pretty
   7 ;;;; deeply.
   8
   9 ;;;; This software is part of the SBCL system. See the README file for
  10 ;;;; more information.
  11
  12 ;;;; This software is derived from software originally released by Xerox
  13 ;;;; Corporation. Copyright and release statements follow. Later modifications
  14 ;;;; to the software are in the public domain and are provided with
  15 ;;;; absolutely no warranty. See the COPYING and CREDITS files for more
  16 ;;;; information.
  17
  18 ;;;; copyright information from original PCL sources:
  19 ;;;;
  20 ;;;; Copyright (c) 1985, 1986, 1987, 1988, 1989, 1990 Xerox Corporation.
  21 ;;;; All rights reserved.
  22 ;;;;
  23 ;;;; Use and copying of this software and preparation of derivative works based
  24 ;;;; upon this software are permitted. Any distribution of this software or
  25 ;;;; derivative works must comply with all applicable United States export
  26 ;;;; control laws.
  27 ;;;;
  28 ;;;; This software is made available AS IS, and Xerox Corporation makes no
  29 ;;;; warranty about the software, its performance or its conformity to any
  30 ;;;; specification.
  31
  32 (in-package "SB-PCL")
  33
  34 (sb-int:file-comment
  35   "$Header$")
  36 \f
  37 (defun allocate-standard-instance (wrapper
  38                                    &optional (slots-init nil slots-init-p))
  39   (let ((instance (%%allocate-instance--class))
  40         (no-of-slots (wrapper-no-of-instance-slots wrapper)))
  41     (setf (std-instance-wrapper instance) wrapper)
  42     (setf (std-instance-slots instance)
  43           (cond (slots-init-p
  44                  ;; Inline the slots vector allocation and initialization.
  45                  (let ((slots (make-array no-of-slots :initial-element 0)))
  46                    (do ((rem-slots slots-init (rest rem-slots))
  47                         (i 0 (1+ i)))
  48                        ((>= i no-of-slots)) ;endp rem-slots))
  49                      (declare (list rem-slots)
  50                               (type sb-kernel:index i))
  51                      (setf (aref slots i) (first rem-slots)))
  52                    slots))
  53                 (t
  54                  (make-array no-of-slots
  55                              :initial-element sb-pcl::*slot-unbound*))))
  56     instance))
  57
  58 (defmacro allocate-funcallable-instance-slots (wrapper &optional
  59                                                        slots-init-p slots-init)
  60   `(let ((no-of-slots (wrapper-no-of-instance-slots ,wrapper)))
  61      ,(if slots-init-p
  62           `(if ,slots-init-p
  63                (make-array no-of-slots :initial-contents ,slots-init)
  64                (make-array no-of-slots :initial-element *slot-unbound*))
  65           `(make-array no-of-slots :initial-element *slot-unbound*))))
  66
  67 (defun allocate-funcallable-instance (wrapper &optional
  68                                               (slots-init nil slots-init-p))
  69   (let ((fin (allocate-funcallable-instance-1)))
  70     (set-funcallable-instance-function
  71      fin
  72      #'(sb-kernel:instance-lambda (&rest args)
  73          (declare (ignore args))
  74          (error "The function of the funcallable-instance ~S has not been set."
  75                 fin)))
  76     (setf (fsc-instance-wrapper fin) wrapper
  77           (fsc-instance-slots fin) (allocate-funcallable-instance-slots
  78                                     wrapper slots-init-p slots-init))
  79     fin))
  80
  81 (defun allocate-structure-instance (wrapper &optional
  82                                             (slots-init nil slots-init-p))
  83   (let* ((class (wrapper-class wrapper))
  84          (constructor (class-defstruct-constructor class)))
  85     (if constructor
  86         (let ((instance (funcall constructor))
  87               (slots (class-slots class)))
  88           (when slots-init-p
  89             (dolist (slot slots)
  90               (setf (slot-value-using-class class instance slot)
  91                     (pop slots-init))))
  92           instance)
  93         (error "can't allocate an instance of class ~S" (class-name class)))))
  94 \f
  95 ;;;; BOOTSTRAP-META-BRAID
  96 ;;;;
  97 ;;;; This function builds the base metabraid from the early class definitions.
  98 ;;;;
  99 ;;;; FIXME: This, like lotso the other stuff in PCL, is not needed in target
 100 ;;;; Lisp, only at bootstrap time. Perhaps we should do something kludgy like
 101 ;;;; putting a special character (#\$, perhaps) at the beginning of each
 102 ;;;; needed-only-at-bootstrap-time symbol and then UNINTERN them all once we're
 103 ;;;; done bootstrapping?
 104
 105 (defmacro initial-classes-and-wrappers (&rest classes)
 106   `(progn
 107      ,@(mapcar #'(lambda (class)
 108                    (let ((wr (intern (format nil "~A-WRAPPER" class)
 109                                      *pcl-package*)))
 110                      `(setf ,wr ,(if (eq class 'standard-generic-function)
 111                                      '*sgf-wrapper*
 112                                      `(boot-make-wrapper
 113                                        (early-class-size ',class)
 114                                        ',class))
 115                             ,class (allocate-standard-instance
 116                                     ,(if (eq class 'standard-generic-function)
 117                                          'funcallable-standard-class-wrapper
 118                                          'standard-class-wrapper))
 119                             (wrapper-class ,wr) ,class
 120                             (find-class ',class) ,class)))
 121               classes)))
 122
 123 (defun bootstrap-meta-braid ()
 124   (let* ((name 'class)
 125          (predicate-name (make-type-predicate-name name)))
 126     (setf (gdefinition predicate-name)
 127           #'(lambda (x) (declare (ignore x)) t))
 128     (do-satisfies-deftype name predicate-name))
 129   (let* ((*create-classes-from-internal-structure-definitions-p* nil)
 130          std-class-wrapper std-class
 131          standard-class-wrapper standard-class
 132          funcallable-standard-class-wrapper funcallable-standard-class
 133          slot-class-wrapper slot-class
 134          built-in-class-wrapper built-in-class
 135          structure-class-wrapper structure-class
 136          standard-direct-slot-definition-wrapper
 137          standard-direct-slot-definition
 138          standard-effective-slot-definition-wrapper
 139          standard-effective-slot-definition
 140          class-eq-specializer-wrapper class-eq-specializer
 141          standard-generic-function-wrapper standard-generic-function)
 142     (initial-classes-and-wrappers
 143      standard-class funcallable-standard-class
 144      slot-class built-in-class structure-class std-class
 145      standard-direct-slot-definition standard-effective-slot-definition
 146      class-eq-specializer standard-generic-function)
 147     ;; First, make a class metaobject for each of the early classes. For
 148     ;; each metaobject we also set its wrapper. Except for the class T,
 149     ;; the wrapper is always that of STANDARD-CLASS.
 150     (dolist (definition *early-class-definitions*)
 151       (let* ((name (ecd-class-name definition))
 152              (meta (ecd-metaclass definition))
 153              (wrapper (ecase meta
 154                         (slot-class slot-class-wrapper)
 155                         (std-class std-class-wrapper)
 156                         (standard-class standard-class-wrapper)
 157                         (funcallable-standard-class
 158                          funcallable-standard-class-wrapper)
 159                         (built-in-class built-in-class-wrapper)
 160                         (structure-class structure-class-wrapper)))
 161              (class (or (find-class name nil)
 162                         (allocate-standard-instance wrapper))))
 163         (when (or (eq meta 'standard-class)
 164                   (eq meta 'funcallable-standard-class))
 165           (inform-type-system-about-std-class name))
 166         (setf (find-class name) class)))
 167     (dolist (definition *early-class-definitions*)
 168       (let ((name (ecd-class-name definition))
 169             (meta (ecd-metaclass definition))
 170             (source (ecd-source definition))
 171             (direct-supers (ecd-superclass-names definition))
 172             (direct-slots  (ecd-canonical-slots definition))
 173             (other-initargs (ecd-other-initargs definition)))
 174         (let ((direct-default-initargs
 175                (getf other-initargs :direct-default-initargs)))
 176           (multiple-value-bind (slots cpl default-initargs direct-subclasses)
 177               (early-collect-inheritance name)
 178             (let* ((class (find-class name))
 179                    (wrapper (cond ((eq class slot-class)
 180                                    slot-class-wrapper)
 181                                   ((eq class std-class)
 182                                    std-class-wrapper)
 183                                   ((eq class standard-class)
 184                                    standard-class-wrapper)
 185                                   ((eq class funcallable-standard-class)
 186                                    funcallable-standard-class-wrapper)
 187                                   ((eq class standard-direct-slot-definition)
 188                                    standard-direct-slot-definition-wrapper)
 189                                   ((eq class
 190                                        standard-effective-slot-definition)
 191                                    standard-effective-slot-definition-wrapper)
 192                                   ((eq class built-in-class)
 193                                    built-in-class-wrapper)
 194                                   ((eq class structure-class)
 195                                    structure-class-wrapper)
 196                                   ((eq class class-eq-specializer)
 197                                    class-eq-specializer-wrapper)
 198                                   ((eq class standard-generic-function)
 199                                    standard-generic-function-wrapper)
 200                                   (t
 201                                    (boot-make-wrapper (length slots) name))))
 202                    (proto nil))
 203               (when (eq name 't) (setq *the-wrapper-of-t* wrapper))
 204               (set (intern (format nil "*THE-CLASS-~A*" (symbol-name name))
 205                            *pcl-package*)
 206                    class)
 207               (dolist (slot slots)
 208                 (unless (eq (getf slot :allocation :instance) :instance)
 209                   (error "Slot allocation ~S is not supported in bootstrap.")))
 210
 211               (when (typep wrapper 'wrapper)
 212                 (setf (wrapper-instance-slots-layout wrapper)
 213                       (mapcar #'canonical-slot-name slots))
 214                 (setf (wrapper-class-slots wrapper)
 215                       ()))
 216
 217               (setq proto (if (eq meta 'funcallable-standard-class)
 218                               (allocate-funcallable-instance wrapper)
 219                               (allocate-standard-instance wrapper)))
 220
 221               (setq direct-slots
 222                     (bootstrap-make-slot-definitions
 223                      name class direct-slots
 224                      standard-direct-slot-definition-wrapper nil))
 225               (setq slots
 226                     (bootstrap-make-slot-definitions
 227                      name class slots
 228                      standard-effective-slot-definition-wrapper t))
 229
 230               (case meta
 231                 ((std-class standard-class funcallable-standard-class)
 232                  (bootstrap-initialize-class
 233                   meta
 234                   class name class-eq-specializer-wrapper source
 235                   direct-supers direct-subclasses cpl wrapper proto
 236                   direct-slots slots direct-default-initargs default-initargs))
 237                 (built-in-class         ; *the-class-t*
 238                  (bootstrap-initialize-class
 239                   meta
 240                   class name class-eq-specializer-wrapper source
 241                   direct-supers direct-subclasses cpl wrapper proto))
 242                 (slot-class             ; *the-class-slot-object*
 243                  (bootstrap-initialize-class
 244                   meta
 245                   class name class-eq-specializer-wrapper source
 246                   direct-supers direct-subclasses cpl wrapper proto))
 247                 (structure-class        ; *the-class-structure-object*
 248                  (bootstrap-initialize-class
 249                   meta
 250                   class name class-eq-specializer-wrapper source
 251                   direct-supers direct-subclasses cpl wrapper))))))))
 252
 253     (let* ((smc-class (find-class 'standard-method-combination))
 254            (smc-wrapper (bootstrap-get-slot 'standard-class
 255                                             smc-class
 256                                             'wrapper))
 257            (smc (allocate-standard-instance smc-wrapper)))
 258       (flet ((set-slot (name value)
 259                (bootstrap-set-slot 'standard-method-combination
 260                                    smc
 261                                    name
 262                                    value)))
 263         (set-slot 'source *load-truename*)
 264         (set-slot 'type 'standard)
 265         (set-slot 'documentation "The standard method combination.")
 266         (set-slot 'options ()))
 267       (setq *standard-method-combination* smc))))
 268
 269 ;;; Initialize a class metaobject.
 270 ;;;
 271 ;;; FIXME: This and most stuff in this file is probably only needed at init
 272 ;;; time.
 273 (defun bootstrap-initialize-class
 274        (metaclass-name class name
 275         class-eq-wrapper source direct-supers direct-subclasses cpl wrapper
 276         &optional
 277         proto direct-slots slots direct-default-initargs default-initargs)
 278   (flet ((classes (names) (mapcar #'find-class names))
 279          (set-slot (slot-name value)
 280            (bootstrap-set-slot metaclass-name class slot-name value)))
 281     (set-slot 'name name)
 282     (set-slot 'source source)
 283     (set-slot 'type (if (eq class (find-class 't))
 284                         t
 285                         `(class ,class)))
 286     (set-slot 'class-eq-specializer
 287               (let ((spec (allocate-standard-instance class-eq-wrapper)))
 288                 (bootstrap-set-slot 'class-eq-specializer spec 'type
 289                                     `(class-eq ,class))
 290                 (bootstrap-set-slot 'class-eq-specializer spec 'object
 291                                     class)
 292                 spec))
 293     (set-slot 'class-precedence-list (classes cpl))
 294     (set-slot 'can-precede-list (classes (cdr cpl)))
 295     (set-slot 'incompatible-superclass-list nil)
 296     (set-slot 'direct-superclasses (classes direct-supers))
 297     (set-slot 'direct-subclasses (classes direct-subclasses))
 298     (set-slot 'direct-methods (cons nil nil))
 299     (set-slot 'wrapper wrapper)
 300     (set-slot 'predicate-name (or (cadr (assoc name *early-class-predicates*))
 301                                   (make-class-predicate-name name)))
 302     (set-slot 'plist
 303               `(,@(and direct-default-initargs
 304                        `(direct-default-initargs ,direct-default-initargs))
 305                 ,@(and default-initargs
 306                        `(default-initargs ,default-initargs))))
 307     (when (memq metaclass-name '(standard-class funcallable-standard-class
 308                                  structure-class slot-class std-class))
 309       (set-slot 'direct-slots direct-slots)
 310       (set-slot 'slots slots)
 311       (set-slot 'initialize-info nil))
 312     (if (eq metaclass-name 'structure-class)
 313         (let ((constructor-sym '|STRUCTURE-OBJECT class constructor|))
 314           (set-slot 'predicate-name (or (cadr (assoc name
 315                                                      *early-class-predicates*))
 316                                         (make-class-predicate-name name)))
 317           (set-slot 'defstruct-form
 318                     `(defstruct (structure-object (:constructor
 319                                                    ,constructor-sym))))
 320           (set-slot 'defstruct-constructor constructor-sym)
 321           (set-slot 'from-defclass-p t)
 322           (set-slot 'plist nil)
 323           (set-slot 'prototype (funcall constructor-sym)))
 324         (set-slot 'prototype (or proto (allocate-standard-instance wrapper))))
 325     class))
 326
 327 (defun bootstrap-make-slot-definitions (name class slots wrapper effective-p)
 328   (let ((index -1))
 329     (mapcar #'(lambda (slot)
 330                 (incf index)
 331                 (bootstrap-make-slot-definition
 332                   name class slot wrapper effective-p index))
 333             slots)))
 334
 335 (defun bootstrap-make-slot-definition
 336     (name class slot wrapper effective-p index)
 337   (let* ((slotd-class-name (if effective-p
 338                                'standard-effective-slot-definition
 339                                'standard-direct-slot-definition))
 340          (slotd (allocate-standard-instance wrapper))
 341          (slot-name (getf slot :name)))
 342     (flet ((get-val (name) (getf slot name))
 343            (set-val (name val)
 344                     (bootstrap-set-slot slotd-class-name slotd name val)))
 345       (set-val 'name     slot-name)
 346       (set-val 'initform     (get-val :initform))
 347       (set-val 'initfunction (get-val :initfunction))
 348       (set-val 'initargs     (get-val :initargs))
 349       (set-val 'readers      (get-val :readers))
 350       (set-val 'writers      (get-val :writers))
 351       (set-val 'allocation   :instance)
 352       (set-val 'type     (or (get-val :type) t))
 353       (set-val 'documentation (or (get-val :documentation) ""))
 354       (set-val 'class   class)
 355       (when effective-p
 356         (set-val 'location index)
 357         (let ((fsc-p nil))
 358           (set-val 'reader-function (make-optimized-std-reader-method-function
 359                                      fsc-p slot-name index))
 360           (set-val 'writer-function (make-optimized-std-writer-method-function
 361                                      fsc-p slot-name index))
 362           (set-val 'boundp-function (make-optimized-std-boundp-method-function
 363                                      fsc-p slot-name index)))
 364         (set-val 'accessor-flags 7)
 365         (let ((table (or (gethash slot-name *name->class->slotd-table*)
 366                          (setf (gethash slot-name *name->class->slotd-table*)
 367                                (make-hash-table :test 'eq :size 5)))))
 368           (setf (gethash class table) slotd)))
 369       (when (and (eq name 'standard-class)
 370                  (eq slot-name 'slots) effective-p)
 371         (setq *the-eslotd-standard-class-slots* slotd))
 372       (when (and (eq name 'funcallable-standard-class)
 373                  (eq slot-name 'slots) effective-p)
 374         (setq *the-eslotd-funcallable-standard-class-slots* slotd))
 375       slotd)))
 376
 377 (defun bootstrap-accessor-definitions (early-p)
 378   (let ((*early-p* early-p))
 379     (dolist (definition *early-class-definitions*)
 380       (let ((name (ecd-class-name definition))
 381             (meta (ecd-metaclass definition)))
 382         (unless (eq meta 'built-in-class)
 383           (let ((direct-slots  (ecd-canonical-slots definition)))
 384             (dolist (slotd direct-slots)
 385               (let ((slot-name (getf slotd :name))
 386                     (readers (getf slotd :readers))
 387                     (writers (getf slotd :writers)))
 388                 (bootstrap-accessor-definitions1
 389                  name
 390                  slot-name
 391                  readers
 392                  writers
 393                  nil)
 394                 (bootstrap-accessor-definitions1
 395                  'slot-object
 396                  slot-name
 397                  (list (slot-reader-symbol slot-name))
 398                  (list (slot-writer-symbol slot-name))
 399                  (list (slot-boundp-symbol slot-name)))))))))))
 400
 401 (defun bootstrap-accessor-definition (class-name accessor-name slot-name type)
 402   (multiple-value-bind (accessor-class make-method-function arglist specls doc)
 403       (ecase type
 404         (reader (values 'standard-reader-method
 405                         #'make-std-reader-method-function
 406                         (list class-name)
 407                         (list class-name)
 408                         "automatically generated reader method"))
 409         (writer (values 'standard-writer-method
 410                         #'make-std-writer-method-function
 411                         (list 'new-value class-name)
 412                         (list 't class-name)
 413                         "automatically generated writer method"))
 414         (boundp (values 'standard-boundp-method
 415                         #'make-std-boundp-method-function
 416                         (list class-name)
 417                         (list class-name)
 418                         "automatically generated boundp method")))
 419     (let ((gf (ensure-generic-function accessor-name)))
 420       (if (find specls (early-gf-methods gf)
 421                 :key #'early-method-specializers
 422                 :test 'equal)
 423           (unless (assoc accessor-name *generic-function-fixups*
 424                          :test #'equal)
 425             (update-dfun gf))
 426           (add-method gf
 427                       (make-a-method accessor-class
 428                                      ()
 429                                      arglist specls
 430                                      (funcall make-method-function
 431                                               class-name slot-name)
 432                                      doc
 433                                      slot-name))))))
 434
 435 (defun bootstrap-accessor-definitions1 (class-name
 436                                         slot-name
 437                                         readers
 438                                         writers
 439                                         boundps)
 440   (flet ((do-reader-definition (reader)
 441            (bootstrap-accessor-definition class-name
 442                                           reader
 443                                           slot-name
 444                                           'reader))
 445          (do-writer-definition (writer)
 446            (bootstrap-accessor-definition class-name
 447                                           writer
 448                                           slot-name
 449                                           'writer))
 450          (do-boundp-definition (boundp)
 451            (bootstrap-accessor-definition class-name
 452                                           boundp
 453                                           slot-name
 454                                           'boundp)))
 455     (dolist (reader readers) (do-reader-definition reader))
 456     (dolist (writer writers) (do-writer-definition writer))
 457     (dolist (boundp boundps) (do-boundp-definition boundp))))
 458
 459 (defun bootstrap-class-predicates (early-p)
 460   (let ((*early-p* early-p))
 461     (dolist (definition *early-class-definitions*)
 462       (let* ((name (ecd-class-name definition))
 463              (class (find-class name)))
 464         (setf (find-class-predicate name)
 465               (make-class-predicate class (class-predicate-name class)))))))
 466
 467 (defun bootstrap-built-in-classes ()
 468
 469   ;; First make sure that all the supers listed in
 470   ;; *BUILT-IN-CLASS-LATTICE* are themselves defined by
 471   ;; *BUILT-IN-CLASS-LATTICE*. This is just to check for typos and
 472   ;; other sorts of brainos.
 473   (dolist (e *built-in-classes*)
 474     (dolist (super (cadr e))
 475       (unless (or (eq super 't)
 476                   (assq super *built-in-classes*))
 477         (error "in *BUILT-IN-CLASSES*: ~S has ~S as a super,~%~
 478                 but ~S is not itself a class in *BUILT-IN-CLASSES*."
 479                (car e) super super))))
 480
 481   ;; In the first pass, we create a skeletal object to be bound to the
 482   ;; class name.
 483   (let* ((built-in-class (find-class 'built-in-class))
 484          (built-in-class-wrapper (class-wrapper built-in-class)))
 485     (dolist (e *built-in-classes*)
 486       (let ((class (allocate-standard-instance built-in-class-wrapper)))
 487         (setf (find-class (car e)) class))))
 488
 489   ;; In the second pass, we initialize the class objects.
 490   (let ((class-eq-wrapper (class-wrapper (find-class 'class-eq-specializer))))
 491     (dolist (e *built-in-classes*)
 492       (destructuring-bind (name supers subs cpl prototype) e
 493         (let* ((class (find-class name))
 494                (lclass (cl:find-class name))
 495                (wrapper (sb-kernel:class-layout lclass)))
 496           (set (get-built-in-class-symbol name) class)
 497           (set (get-built-in-wrapper-symbol name) wrapper)
 498           (setf (sb-kernel:class-pcl-class lclass) class)
 499
 500           (bootstrap-initialize-class 'built-in-class class
 501                                       name class-eq-wrapper nil
 502                                       supers subs
 503                                       (cons name cpl)
 504                                       wrapper prototype)))))
 505
 506   (dolist (e *built-in-classes*)
 507     (let* ((name (car e))
 508            (class (find-class name)))
 509       (setf (find-class-predicate name)
 510             (make-class-predicate class (class-predicate-name class))))))
 511 \f
 512 (defmacro wrapper-of-macro (x)
 513   `(sb-kernel:layout-of ,x))
 514
 515 (defun class-of (x)
 516   (wrapper-class* (wrapper-of-macro x)))
 517
 518 ;;; FIXME: We probably don't need both WRAPPER-OF and WRAPPER-OF-MACRO.
 519 #-sb-fluid (declaim (inline wrapper-of))
 520 (defun wrapper-of (x)
 521   (wrapper-of-macro x))
 522
 523 (defvar *find-structure-class* nil)
 524
 525 (defun eval-form (form)
 526   #'(lambda () (eval form)))
 527
 528 (defun slot-initargs-from-structure-slotd (slotd)
 529   `(:name ,(structure-slotd-name slotd)
 530     :defstruct-accessor-symbol ,(structure-slotd-accessor-symbol slotd)
 531     :internal-reader-function ,(structure-slotd-reader-function slotd)
 532     :internal-writer-function ,(structure-slotd-writer-function slotd)
 533     :type ,(or (structure-slotd-type slotd) t)
 534     :initform ,(structure-slotd-init-form slotd)
 535     :initfunction ,(eval-form (structure-slotd-init-form slotd))))
 536
 537 (defun find-structure-class (symbol)
 538   (if (structure-type-p symbol)
 539       (unless (eq *find-structure-class* symbol)
 540         (let ((*find-structure-class* symbol))
 541           (ensure-class symbol
 542                         :metaclass 'structure-class
 543                         :name symbol
 544                         :direct-superclasses
 545                         (cond ;; Handle our CMU-CL-ish structure-based
 546                               ;; conditions.
 547                               ((cl:subtypep symbol 'condition)
 548                                (mapcar #'cl:class-name
 549                                        (sb-kernel:class-direct-superclasses
 550                                         (cl:find-class symbol))))
 551                               ;; a hack to add the STREAM class as a
 552                               ;; mixin to the LISP-STREAM class.
 553                               ((eq symbol 'sb-sys:lisp-stream)
 554                                '(structure-object stream))
 555                               ((structure-type-included-type-name symbol)
 556                                (list (structure-type-included-type-name
 557                                       symbol))))
 558                         :direct-slots
 559                         (mapcar #'slot-initargs-from-structure-slotd
 560                                 (structure-type-slot-description-list
 561                                  symbol)))))
 562       (error "~S is not a legal structure class name." symbol)))
 563 \f
 564 (defun method-function-returning-nil (args next-methods)
 565   (declare (ignore args next-methods))
 566   nil)
 567
 568 (defun method-function-returning-t (args next-methods)
 569   (declare (ignore args next-methods))
 570   t)
 571
 572 (defun make-class-predicate (class name)
 573   (let* ((gf (ensure-generic-function name))
 574          (mlist (if (eq *boot-state* 'complete)
 575                     (generic-function-methods gf)
 576                     (early-gf-methods gf))))
 577     (unless mlist
 578       (unless (eq class *the-class-t*)
 579         (let* ((default-method-function #'method-function-returning-nil)
 580                (default-method-initargs (list :function
 581                                               default-method-function))
 582                (default-method (make-a-method 'standard-method
 583                                               ()
 584                                               (list 'object)
 585                                               (list *the-class-t*)
 586                                               default-method-initargs
 587                                               "class predicate default method")))
 588           (setf (method-function-get default-method-function :constant-value)
 589                 nil)
 590           (add-method gf default-method)))
 591       (let* ((class-method-function #'method-function-returning-t)
 592              (class-method-initargs (list :function
 593                                           class-method-function))
 594              (class-method (make-a-method 'standard-method
 595                                           ()
 596                                           (list 'object)
 597                                           (list class)
 598                                           class-method-initargs
 599                                           "class predicate class method")))
 600         (setf (method-function-get class-method-function :constant-value) t)
 601         (add-method gf class-method)))
 602     gf))
 603
 604 ;;; Set the inherits from CPL, and register the layout. This actually
 605 ;;; installs the class in the Lisp type system.
 606 (defun update-lisp-class-layout (class layout)
 607   (let ((lclass (sb-kernel:layout-class layout)))
 608     (unless (eq (sb-kernel:class-layout lclass) layout)
 609       (setf (sb-kernel:layout-inherits layout)
 610             (map 'vector #'class-wrapper
 611                  (reverse (rest (class-precedence-list class)))))
 612       (sb-kernel:register-layout layout :invalidate nil)
 613
 614       ;; Subclasses of formerly forward-referenced-class may be unknown
 615       ;; to CL:FIND-CLASS and also anonymous. This functionality moved
 616       ;; here from (SETF FIND-CLASS).
 617       (let ((name (class-name class)))
 618         (setf (cl:find-class name) lclass
 619               ;; FIXME: It's nasty to use double colons. Perhaps the
 620               ;; best way to fix this is not to export CLASS-%NAME
 621               ;; from SB-KERNEL, but instead to move the whole
 622               ;; UPDATE-LISP-CLASS-LAYOUT function to SB-KERNEL, and
 623               ;; export it. (since it's also nasty for us to be
 624               ;; reaching into %KERNEL implementation details my
 625               ;; messing with raw CLASS-%NAME)
 626               (sb-kernel::class-%name lclass) name)))))
 627
 628 (eval-when (:load-toplevel :execute)
 629
 630   (clrhash *find-class*)
 631   (bootstrap-meta-braid)
 632   (bootstrap-accessor-definitions t)
 633   (bootstrap-class-predicates t)
 634   (bootstrap-accessor-definitions nil)
 635   (bootstrap-class-predicates nil)
 636   (bootstrap-built-in-classes)
 637
 638   (sb-int:dohash (name x *find-class*)
 639     (let* ((class (find-class-from-cell name x))
 640            (layout (class-wrapper class))
 641            (lclass (sb-kernel:layout-class layout))
 642            (lclass-pcl-class (sb-kernel:class-pcl-class lclass))
 643            (olclass (cl:find-class name nil)))
 644       (if lclass-pcl-class
 645           (assert (eq class lclass-pcl-class))
 646           (setf (sb-kernel:class-pcl-class lclass) class))
 647
 648       (update-lisp-class-layout class layout)
 649
 650       (cond (olclass
 651              (assert (eq lclass olclass)))
 652             (t
 653              (setf (cl:find-class name) lclass)))))
 654
 655   (setq *boot-state* 'braid)
 656
 657   ) ; EVAL-WHEN
 658
 659 (defmethod no-applicable-method (generic-function &rest args)
 660   ;; FIXME: probably could be ERROR instead of CERROR
 661   (cerror "Retry call to ~S."
 662           "There is no matching method for the generic function ~S~@
 663           when called with arguments ~S."
 664           generic-function
 665           args)
 666   (apply generic-function args))