src/code/kernel.lisp

   1 ;;;; miscellaneous kernel-level definitions
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!KERNEL")
  13
  14 ;;; Return the 24 bits of data in the header of object X, which must
  15 ;;; be an other-pointer object.
  16 (defun get-header-data (x)
  17   (get-header-data x))
  18
  19 ;;; Set the 24 bits of data in the header of object X (which must be
  20 ;;; an other-pointer object) to VAL.
  21 (defun set-header-data (x val)
  22   (set-header-data x val))
  23
  24 ;;; Return the 24 bits of data in the header of object X, which must
  25 ;;; be a fun-pointer object.
  26 ;;;
  27 ;;; FIXME: Should this not be called GET-FUN-LENGTH instead? Or even better
  28 ;;; yet, if GET-HEADER-DATA masked the lowtag instead of substracting it, we
  29 ;;; could just use it instead -- or at least this could just be a function on
  30 ;;; top of the same VOP.
  31 (defun get-closure-length (x)
  32   (get-closure-length x))
  33
  34 (defun lowtag-of (x)
  35   (lowtag-of x))
  36
  37 (defun widetag-of (x)
  38   (widetag-of x))
  39
  40 ;;; WIDETAG-OF needs extra code to handle LIST and FUNCTION lowtags. When
  41 ;;; we're only dealing with other pointers (eg. when dispatching on array
  42 ;;; element type), this is going to be faster.
  43 (defun %other-pointer-widetag (x)
  44   (%other-pointer-widetag x))
  45
  46 ;;; Return a System-Area-Pointer pointing to the data for the vector
  47 ;;; X, which must be simple.
  48 ;;;
  49 ;;; FIXME: So it should be SIMPLE-VECTOR-SAP, right? (or UNHAIRY-VECTOR-SAP,
  50 ;;; if the meaning is (SIMPLE-ARRAY * 1) instead of SIMPLE-VECTOR)
  51 ;;; (or maybe SIMPLE-VECTOR-DATA-SAP or UNHAIRY-VECTOR-DATA-SAP?)
  52 (defun vector-sap (x)
  53   (declare (type (simple-unboxed-array (*)) x))
  54   (vector-sap x))
  55
  56 ;;; Return a System-Area-Pointer pointing to the end of the binding stack.
  57 (defun sb!c::binding-stack-pointer-sap ()
  58   (sb!c::binding-stack-pointer-sap))
  59
  60 ;;; Return a System-Area-Pointer pointing to the next free word of the
  61 ;;; current dynamic space.
  62 (defun sb!c::dynamic-space-free-pointer ()
  63   (sb!c::dynamic-space-free-pointer))
  64
  65 ;;; Return a System-Area-Pointer pointing to the end of the control stack.
  66 (defun sb!c::control-stack-pointer-sap ()
  67   (sb!c::control-stack-pointer-sap))
  68
  69 ;;; FDEFN -> FUNCTION
  70 (defun sb!c:safe-fdefn-fun (x) (sb!c:safe-fdefn-fun x))
  71
  72 ;;; Return the header typecode for FUNCTION. Can be set with SETF.
  73 (defun fun-subtype (function)
  74   (fun-subtype function))
  75 (defun (setf fun-subtype) (type function)
  76   (setf (fun-subtype function) type))
  77
  78 ;;;; SIMPLE-FUN and accessors
  79
  80 (defun simple-fun-p (object)
  81   (simple-fun-p object))
  82
  83 (deftype simple-fun ()
  84   '(satisfies simple-fun-p))
  85
  86 (defun %simple-fun-doc (simple-fun)
  87   (declare (simple-fun simple-fun))
  88   (let ((info (%simple-fun-info simple-fun)))
  89     (cond ((typep info '(or null string))
  90            info)
  91           ((simple-vector-p info)
  92            nil)
  93           ((consp info)
  94            (car info))
  95           (t
  96            (bug "bogus INFO for ~S: ~S" simple-fun info)))))
  97
  98 (defun (setf %simple-fun-doc) (doc simple-fun)
  99   (declare (type (or null string) doc)
 100            (simple-fun simple-fun))
 101   (let ((info (%simple-fun-info simple-fun)))
 102     (setf (%simple-fun-info simple-fun)
 103           (cond ((typep info '(or null string))
 104                  doc)
 105                 ((simple-vector-p info)
 106                  (if doc
 107                      (cons doc info)
 108                      info))
 109                 ((consp info)
 110                  (if doc
 111                      (cons doc (cdr info))
 112                      (cdr info)))
 113                 (t
 114                  (bug "bogus INFO for ~S: ~S" simple-fun info))))))
 115
 116 (defun %simple-fun-xrefs (simple-fun)
 117   (declare (simple-fun simple-fun))
 118   (let ((info (%simple-fun-info simple-fun)))
 119     (cond ((typep info '(or null string))
 120            nil)
 121           ((simple-vector-p info)
 122            info)
 123           ((consp info)
 124            (cdr info))
 125           (t
 126            (bug "bogus INFO for ~S: ~S" simple-fun info)))))
 127
 128 ;;; Extract the arglist from the function header FUNC.
 129 (defun %simple-fun-arglist (func)
 130   (%simple-fun-arglist func))
 131
 132 (defun (setf %simple-fun-arglist) (new-value func)
 133   (setf (%simple-fun-arglist func) new-value))
 134
 135 ;;; Extract the name from the function header FUNC.
 136 (defun %simple-fun-name (func)
 137   (%simple-fun-name func))
 138
 139 (defun (setf %simple-fun-name) (new-value func)
 140   (setf (%simple-fun-name func) new-value))
 141
 142 ;;; Extract the type from the function header FUNC.
 143 (defun %simple-fun-type (func)
 144   (let ((internal-type (sb!vm::%%simple-fun-type func)))
 145     ;; For backward-compatibility we expand SFUNCTION -> FUNCTION.
 146     (if (and (listp internal-type) (eq (car internal-type) 'sfunction))
 147         (sb!ext:typexpand-1 internal-type)
 148         internal-type)))
 149
 150 (defun %simple-fun-next (simple-fun)
 151   (%simple-fun-next simple-fun))
 152
 153 ;; Given either a closure or a simple-fun, return the underlying simple-fun.
 154 ;; FIXME: %SIMPLE-FUN-SELF is a somewhat poor name for this function.
 155 ;; The x86[-64] code defines %CLOSURE-FUN as nothing more than %SIMPLE-FUN-SELF,
 156 ;; and it's not clear whether that's because callers need the "simple" accessor
 157 ;; to work on closures, versus reluctance to define a %CLOSURE/SIMPLE-FUN-FUN
 158 ;; reader. %FUN-FUN works on all three function subtypes, but is nontrivial.
 159 ;; Preferably at least one accessor should get a new name,
 160 ;; so that %SIMPLE-FUN-SELF can mean what it says.
 161
 162 (defun %simple-fun-self (simple-fun)
 163   (%simple-fun-self simple-fun))
 164
 165 ;;;; CLOSURE type and accessors
 166
 167 (defun closurep (object)
 168   (closurep object))
 169
 170 (deftype closure ()
 171   '(satisfies closurep))
 172
 173 (defmacro do-closure-values ((value closure) &body body)
 174   (with-unique-names (i nclosure)
 175     `(let ((,nclosure ,closure))
 176        (declare (closure ,nclosure))
 177        (dotimes (,i (- (1+ (get-closure-length ,nclosure)) sb!vm:closure-info-offset))
 178          (let ((,value (%closure-index-ref ,nclosure ,i)))
 179            ,@body)))))
 180
 181 (defun %closure-values (closure)
 182   (declare (closure closure))
 183   (let (values)
 184     (do-closure-values (elt closure)
 185       (push elt values))
 186     (nreverse values)))
 187
 188 ;;; Extract the function from CLOSURE.
 189 (defun %closure-fun (closure)
 190   (%closure-fun closure))
 191
 192 ;;; Extract the INDEXth slot from CLOSURE.
 193 (defun %closure-index-ref (closure index)
 194   (%closure-index-ref closure index))
 195
 196 ;;; Return the length of VECTOR. There is no reason to use this in
 197 ;;; ordinary code, 'cause length (the vector foo)) is the same.
 198 (defun sb!c::vector-length (vector)
 199   (sb!c::vector-length vector))
 200
 201 ;;; Allocate a unboxed, simple vector with type code TYPE, length LENGTH, and
 202 ;;; WORDS words long. Note: it is your responsibility to ensure that the
 203 ;;; relation between LENGTH and WORDS is correct.
 204 (defun allocate-vector (type length words)
 205   (allocate-vector type length words))
 206
 207 ;;; Allocate an array header with type code TYPE and rank RANK.
 208 (defun make-array-header (type rank)
 209   (make-array-header type rank))
 210
 211 ;;; Return a SAP pointing to the instructions part of CODE-OBJ.
 212 (defun code-instructions (code-obj)
 213   (code-instructions code-obj))
 214
 215 ;;; Extract the INDEXth element from the header of CODE-OBJ. Can be
 216 ;;; set with SETF.
 217 (defun code-header-ref (code-obj index)
 218   (code-header-ref code-obj index))
 219
 220 (defun code-header-set (code-obj index new)
 221   (code-header-set code-obj index new))
 222
 223 (defun %vector-raw-bits (object offset)
 224   (declare (type index offset))
 225   (%vector-raw-bits object offset))
 226
 227 (defun %set-vector-raw-bits (object offset value)
 228   (declare (type index offset))
 229   (declare (type word value))
 230   (setf (%vector-raw-bits object offset) value))
 231
 232 (defun make-single-float (x) (make-single-float x))
 233 (defun make-double-float (hi lo) (make-double-float hi lo))
 234
 235 (defun single-float-bits (x) (single-float-bits x))
 236 (defun double-float-high-bits (x) (double-float-high-bits x))
 237 (defun double-float-low-bits (x) (double-float-low-bits x))
 238
 239 (defun value-cell-ref (x) (value-cell-ref x))
 240
 241 ;;; A unique GC id. This is supplied for code that needs to detect
 242 ;;; whether a GC has happened since some earlier point in time. For
 243 ;;; example:
 244 ;;;
 245 ;;;   (let ((epoch *gc-epoch*))
 246 ;;;      ...
 247 ;;;      (unless (eql epoch *gc-epoch)
 248 ;;;        ....))
 249 ;;;
 250 ;;; This isn't just a fixnum counter since then we'd have theoretical
 251 ;;; problems when exactly 2^29 GCs happen between epoch
 252 ;;; comparisons. Unlikely, but the cost of using a cons instead is too
 253 ;;; small to measure. -- JES, 2007-09-30
 254 (declaim (type cons *gc-epoch*))
 255 (!defglobal *gc-epoch* '(nil . nil))