;;;; DEF!STRUCT = bootstrap DEFSTRUCT, a wrapper around DEFSTRUCT which ;;;; provides special features to help at bootstrap time: ;;;; 1. Layout information, inheritance information, and so forth is ;;;; retained in such a way that we can get to it even on vanilla ;;;; ANSI Common Lisp at cross-compiler build time. ;;;; 2. MAKE-LOAD-FORM information is stored in such a way that we can ;;;; get to it at bootstrap time before CLOS is built. This is ;;;; important because at least as of sbcl-0.6.11.26, CLOS is built ;;;; (compiled) after cold init, so we need to have the compiler ;;;; even before CLOS runs. ;;;; This software is part of the SBCL system. See the README file for ;;;; more information. ;;;; ;;;; This software is derived from the CMU CL system, which was ;;;; written at Carnegie Mellon University and released into the ;;;; public domain. The software is in the public domain and is ;;;; provided with absolutely no warranty. See the COPYING and CREDITS ;;;; files for more information. (in-package "SB!KERNEL") ;;; A bootstrap MAKE-LOAD-FORM method can be a function or the name ;;; of a function. (deftype def!struct-type-make-load-form-fun () '(or function symbol)) ;;; a little single-inheritance system to keep track of MAKE-LOAD-FORM ;;; information for DEF!STRUCT-defined types (eval-when (#-sb-xc :compile-toplevel :load-toplevel :execute) ;; (DEF!STRUCT-SUPERTYPE TYPE) is the DEF!STRUCT-defined type that ;; TYPE inherits from, or NIL if none. (defvar *def!struct-supertype* (make-hash-table)) (defun def!struct-supertype (type) (multiple-value-bind (value value-p) (gethash type *def!struct-supertype*) (unless value-p (error "~S is not a DEF!STRUCT-defined type." type)) value)) (defun (setf def!struct-supertype) (value type) (when (and value #-sb-xc-host *type-system-initialized*) (aver (subtypep value 'structure!object)) (aver (subtypep type value))) (setf (gethash type *def!struct-supertype*) value)) ;; (DEF!STRUCT-TYPE-MAKE-LOAD-FORM-FUN TYPE) is the load form ;; generator associated with the DEF!STRUCT-defined structure named ;; TYPE, stored in a way which works independently of CLOS. The ;; *DEF!STRUCT-TYPE-MAKE-LOAD-FORM-FUN* table is used to store the ;; values. All types defined by DEF!STRUCT have an entry in the ;; table; those with no MAKE-LOAD-FORM function have an explicit NIL ;; entry. (defvar *def!struct-type-make-load-form-fun* (make-hash-table)) (defun def!struct-type-make-load-form-fun (type) (do ((supertype type)) (nil) (multiple-value-bind (value value-p) (gethash supertype *def!struct-type-make-load-form-fun*) (unless value-p (error "~S (supertype of ~S) is not a DEF!STRUCT-defined type." supertype type)) (when value (return value)) (setf supertype (def!struct-supertype supertype)) (unless supertype (error "There is no MAKE-LOAD-FORM function for bootstrap type ~S." type))))) (defun (setf def!struct-type-make-load-form-fun) (new-value type) (when #+sb-xc-host t #-sb-xc-host *type-system-initialized* (aver (subtypep type 'structure!object)) (aver (typep new-value 'def!struct-type-make-load-form-fun))) (setf (gethash type *def!struct-type-make-load-form-fun*) new-value))) ;;; the simplest, most vanilla MAKE-LOAD-FORM function for DEF!STRUCT ;;; objects (defun just-dump-it-normally (object &optional (env nil env-p)) (declare (type structure!object object)) (if env-p (sb!xc:make-load-form-saving-slots object :environment env) (sb!xc:make-load-form-saving-slots object))) ;;; a MAKE-LOAD-FORM function for objects which don't use the load ;;; form system. This is used for LAYOUT objects because the special ;;; dumping requirements of LAYOUT objects are met by using special ;;; VOPs which bypass the load form system. It's also used for various ;;; compiler internal structures like nodes and VOP-INFO (FIXME: ;;; Why?). (defun ignore-it (object &optional env) (declare (type structure!object object)) (declare (ignore object env)) ;; This magic tag is handled specially by the compiler downstream. :ignore-it) ;;; machinery used in the implementation of DEF!STRUCT #+sb-xc-host (eval-when (:compile-toplevel :load-toplevel :execute) ;; a description of a DEF!STRUCT call to be stored until we get ;; enough of the system running to finish processing it (defstruct delayed-def!struct (args (missing-arg) :type cons) (package (sane-package) :type package)) ;; a list of DELAYED-DEF!STRUCTs stored until we get DEF!STRUCT ;; working fully so that we can apply it to them then. After ;; DEF!STRUCT is made to work fully, this list is processed, then ;; made unbound, and should no longer be used. (defvar *delayed-def!structs* nil)) (eval-when (:compile-toplevel :load-toplevel :execute) ;; Parse the arguments for a DEF!STRUCT call, and return ;; (VALUES NAME DEFSTRUCT-ARGS MAKE-LOAD-FORM-FUN DEF!STRUCT-SUPERTYPE), ;; where NAME is the name of the new type, DEFSTRUCT-ARGS is the ;; munged result suitable for passing on to DEFSTRUCT, ;; MAKE-LOAD-FORM-FUN is the make load form function, or NIL if ;; there's none, and DEF!STRUCT-SUPERTYPE is the direct supertype of ;; the type if it is another DEF!STRUCT-defined type, or NIL ;; otherwise. (defun parse-def!struct-args (nameoid &rest rest) (multiple-value-bind (name options) ; Note: OPTIONS can change below. (if (consp nameoid) (values (first nameoid) (rest nameoid)) (values nameoid nil)) (let* ((include-clause (find :include options :key #'first)) (def!struct-supertype nil) ; may change below (mlff-clause (find :make-load-form-fun options :key #'first)) (mlff (and mlff-clause (second mlff-clause)))) (when (find :type options :key #'first) (error "can't use :TYPE option in DEF!STRUCT")) (when mlff-clause (setf options (remove mlff-clause options))) (when include-clause (setf def!struct-supertype (second include-clause))) (if (eq name 'structure!object) ; if root of hierarchy (aver (not include-clause)) (unless include-clause (setf def!struct-supertype 'structure!object) (push `(:include ,def!struct-supertype) options))) (values name `((,name ,@options) ,@rest) mlff def!struct-supertype))))) ;;; Part of the raison d'etre for DEF!STRUCT is to be able to emulate ;;; these low-level CMU CL functions in a vanilla ANSI Common Lisp ;;; cross compilation host. (The emulation doesn't need to be ;;; efficient, since it's needed for things like dumping objects, not ;;; inner loops.) #+sb-xc-host (progn (defun %instance-length (instance) (aver (typep instance 'structure!object)) (layout-length (class-layout (sb!xc:find-class (type-of instance))))) (defun %instance-ref (instance index) (aver (typep instance 'structure!object)) (let* ((class (sb!xc:find-class (type-of instance))) (layout (class-layout class))) (if (zerop index) layout (let* ((dd (layout-info layout)) (dsd (elt (dd-slots dd) (1- index))) (accessor-name (dsd-accessor-name dsd))) (declare (type symbol accessor-name)) (funcall accessor-name instance))))) (defun %instance-set (instance index new-value) (aver (typep instance 'structure!object)) (let* ((class (sb!xc:find-class (type-of instance))) (layout (class-layout class))) (if (zerop index) (error "can't set %INSTANCE-REF FOO 0 in cross-compilation host") (let* ((dd (layout-info layout)) (dsd (elt (dd-slots dd) (1- index))) (accessor-name (dsd-accessor-name dsd))) (declare (type symbol accessor-name)) (funcall (fdefinition `(setf ,accessor-name)) new-value instance)))))) ;;; a helper function for DEF!STRUCT in the #+SB-XC-HOST case: Return ;;; DEFSTRUCT-style arguments with any class names in the SB!XC ;;; package (i.e. the name of the class being defined, and/or the ;;; names of classes in :INCLUDE clauses) converted from SB!XC::FOO to ;;; CL::FOO. #+sb-xc-host (eval-when (:compile-toplevel :load-toplevel :execute) (defun uncross-defstruct-args (defstruct-args) (destructuring-bind (name-and-options &rest slots-and-doc) defstruct-args (multiple-value-bind (name options) (if (symbolp name-and-options) (values name-and-options nil) (values (first name-and-options) (rest name-and-options))) (flet ((uncross-option (option) (if (eq (first option) :include) (destructuring-bind (include-keyword included-name &rest rest) option `(,include-keyword ,(uncross included-name) ,@rest)) option))) `((,(uncross name) ,@(mapcar #'uncross-option options)) ,@slots-and-doc)))))) ;;; DEF!STRUCT's arguments are like DEFSTRUCT's arguments, except that ;;; DEF!STRUCT accepts an extra optional :MAKE-LOAD-FORM-FUN clause. ;;; DEF!STRUCT also does some magic to ensure that anything it defines ;;; includes STRUCTURE!OBJECT, so that when CLOS is/becomes available, ;;; we can hook the DEF!STRUCT system into ;;; (DEFMETHOD MAKE-LOAD-FORM ((X STRUCTURE!OBJECT) &OPTIONAL ENV) ..) ;;; and everything will continue to work. (defmacro def!struct (&rest args) (multiple-value-bind (name defstruct-args mlff def!struct-supertype) (apply #'parse-def!struct-args args) `(progn ;; Make sure that we really do include STRUCTURE!OBJECT. (If an ;; :INCLUDE clause was used, and the included class didn't ;; itself include STRUCTURE!OBJECT, then we wouldn't; and it's ;; better to find out ASAP then to let the bug lurk until ;; someone tries to do MAKE-LOAD-FORM on the object.) (aver (subtypep ',def!struct-supertype 'structure!object)) (defstruct ,@defstruct-args) (setf (def!struct-type-make-load-form-fun ',name) ,(if (symbolp mlff) `',mlff mlff) (def!struct-supertype ',name) ',def!struct-supertype) ;; This bit of commented-out code hasn't been needed for quite ;; some time, but the comments here about why not might still ;; be useful to me until I finally get the system to work. When ;; I do remove all this, I should be sure also to remove the ;; "outside the EVAL-WHEN" comments above, since they will no ;; longer make sense. -- WHN 19990803 ;;(eval-when (:compile-toplevel :load-toplevel :execute) ;; ;; (The DEFSTRUCT used to be in here, but that failed when trying ;; ;; to cross-compile the hash table implementation.) ;; ;;(defstruct ,@defstruct-args) ;; ;; The (SETF (DEF!STRUCT-TYPE-MAKE-LOAD-FORM-FUN ..) ..) used to ;; ;; be in here too, but that failed an assertion in the SETF ;; ;; definition once we moved the DEFSTRUCT outside.) ;; ) #+sb-xc-host ,(let ((u (uncross-defstruct-args defstruct-args))) (if (boundp '*delayed-def!structs*) `(push (make-delayed-def!struct :args ',u) *delayed-def!structs*) `(sb!xc:defstruct ,@u))) ',name))) ;;; When building the cross-compiler, this function has to be called ;;; some time after SB!XC:DEFSTRUCT is set up, in order to take care ;;; of any processing which had to be delayed until then. #+sb-xc-host (defun force-delayed-def!structs () (if (boundp '*delayed-def!structs*) (progn (mapcar (lambda (x) (let ((*package* (delayed-def!struct-package x))) ;; KLUDGE(?): EVAL is almost always the wrong thing. ;; However, since we have to map DEFSTRUCT over the ;; list, and since ANSI declined to specify any ;; functional primitives corresponding to the ;; DEFSTRUCT macro, it seems to me that EVAL is ;; required in there somewhere.. (eval `(sb!xc:defstruct ,@(delayed-def!struct-args x))))) (reverse *delayed-def!structs*)) ;; We shouldn't need this list any more. Making it unbound ;; serves as a signal to DEF!STRUCT that it needn't delay ;; DEF!STRUCTs any more. It is also generally a good thing for ;; other reasons: it frees garbage, and it discourages anyone ;; else from pushing anything else onto the list later. (makunbound '*delayed-def!structs*)) ;; This condition is probably harmless if it comes up when ;; interactively experimenting with the system by loading a source ;; file into it more than once. But it's worth warning about it ;; because it definitely shouldn't come up in an ordinary build ;; process. (warn "*DELAYED-DEF!STRUCTS* is already unbound."))) ;;; The STRUCTURE!OBJECT abstract class is the base of the type ;;; hierarchy for objects which have/use DEF!STRUCT functionality. ;;; (The extra hackery in DEF!STRUCT-defined things isn't needed for ;;; STRUCTURE-OBJECTs defined by ordinary, post-warm-init programs, so ;;; it's only put into STRUCTURE-OBJECTs which inherit from ;;; STRUCTURE!OBJECT.) (def!struct (structure!object (:constructor nil))) ;;;; hooking this all into the standard MAKE-LOAD-FORM system ;;; MAKE-LOAD-FORM for DEF!STRUCT-defined types (defun structure!object-make-load-form (object &optional env) (declare (ignore env)) (funcall (def!struct-type-make-load-form-fun (type-of object)) object)) ;;; Do the right thing at cold load time. ;;; ;;; (Eventually this MAKE-LOAD-FORM function be overwritten by CLOS's ;;; generic MAKE-LOAD-FORM, at which time a STRUCTURE!OBJECT method ;;; should be added to call STRUCTURE!OBJECT-MAKE-LOAD-FORM.) (setf (symbol-function 'sb!xc:make-load-form) #'structure!object-make-load-form) ;;; Do the right thing in the vanilla ANSI CLOS of the ;;; cross-compilation host. (Something similar will have to be done in ;;; our CLOS, too, but later, some time long after the toplevel forms ;;; of this file have run.) #+sb-xc-host (defmethod make-load-form ((obj structure!object) &optional (env nil env-p)) (if env-p (structure!object-make-load-form obj env) (structure!object-make-load-form obj)))