src/compiler/generic/objdef.lisp

   1 ;;;; machine-independent aspects of the object representation
   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!VM")
  13
  14 ;;;; KLUDGE: The primitive objects here may look like self-contained
  15 ;;;; definitions, but in general they're not. In particular, if you
  16 ;;;; try to add a slot to them, beware of the following:
  17 ;;;;   * (mysterious crashes which occur after changing the length
  18 ;;;;     of SIMPLE-FUN, just adding a new slot not even doing anything
  19 ;;;;     with it, still dunno why)
  20 ;;;;   * The GC scavenging code (and for all I know other GC code too)
  21 ;;;;     is not automatically generated from these layouts, but instead
  22 ;;;;     was hand-written to correspond to them. The offsets are
  23 ;;;;     automatically propagated into the GC scavenging code, but the
  24 ;;;;     existence of slots, and whether they should be scavenged, is
  25 ;;;;     not automatically propagated. Thus e.g. if you add a
  26 ;;;;     SIMPLE-FUN-DEBUG-INFO slot holding a tagged object which needs
  27 ;;;;     to be GCed, you need to tweak scav_code_header() and
  28 ;;;;     verify_space() in gencgc.c, and the corresponding code in gc.c.
  29 ;;;;   * The src/runtime/print.c code (used by LDB) is implemented
  30 ;;;;     using hand-written lists of slot names, which aren't automatically
  31 ;;;;     generated from the code in this file.
  32 ;;;;   * Various code (e.g. STATIC-FSET in genesis.lisp) is hard-wired
  33 ;;;;     to know the name of the last slot of the object the code works
  34 ;;;;     with, and implicitly to know that the last slot is special (being
  35 ;;;;     the beginning of an arbitrary-length sequence of bytes following
  36 ;;;;     the fixed-layout slots).
  37 ;;;; -- WHN 2001-12-29
  38 \f
  39 ;;;; the primitive objects themselves
  40
  41 (define-primitive-object (cons :lowtag list-pointer-lowtag
  42                                :alloc-trans cons)
  43   (car :ref-trans car :set-trans sb!c::%rplaca :init :arg)
  44   (cdr :ref-trans cdr :set-trans sb!c::%rplacd :init :arg))
  45
  46 (define-primitive-object (instance :lowtag instance-pointer-lowtag
  47                                    :widetag instance-header-widetag
  48                                    :alloc-trans %make-instance)
  49   (slots :rest-p t))
  50
  51 (define-primitive-object (bignum :lowtag other-pointer-lowtag
  52                                  :widetag bignum-widetag
  53                                  :alloc-trans sb!bignum::%allocate-bignum)
  54   (digits :rest-p t :c-type #!-alpha "long" #!+alpha "u32"))
  55
  56 (define-primitive-object (ratio :type ratio
  57                                 :lowtag other-pointer-lowtag
  58                                 :widetag ratio-widetag
  59                                 :alloc-trans %make-ratio)
  60   (numerator :type integer
  61              :ref-known (flushable movable)
  62              :ref-trans %numerator
  63              :init :arg)
  64   (denominator :type integer
  65                :ref-known (flushable movable)
  66                :ref-trans %denominator
  67                :init :arg))
  68
  69 #!+#.(cl:if (cl:= sb!vm:n-word-bits 32) '(and) '(or))
  70 (define-primitive-object (single-float :lowtag other-pointer-lowtag
  71                                        :widetag single-float-widetag)
  72   (value :c-type "float"))
  73
  74 (define-primitive-object (double-float :lowtag other-pointer-lowtag
  75                                        :widetag double-float-widetag)
  76   #!-x86-64 (filler)
  77   (value :c-type "double" :length #!-x86-64 2 #!+x86-64 1))
  78
  79 #!+long-float
  80 (define-primitive-object (long-float :lowtag other-pointer-lowtag
  81                                      :widetag long-float-widetag)
  82   #!+sparc (filler)
  83   (value :c-type "long double" :length #!+x86 3 #!+sparc 4))
  84
  85 (define-primitive-object (complex :type complex
  86                                   :lowtag other-pointer-lowtag
  87                                   :widetag complex-widetag
  88                                   :alloc-trans %make-complex)
  89   (real :type real
  90         :ref-known (flushable movable)
  91         :ref-trans %realpart
  92         :init :arg)
  93   (imag :type real
  94         :ref-known (flushable movable)
  95         :ref-trans %imagpart
  96         :init :arg))
  97
  98 (define-primitive-object (array :lowtag other-pointer-lowtag
  99                                 :widetag t)
 100   ;; FILL-POINTER of an ARRAY is in the same place as LENGTH of a
 101   ;; VECTOR -- see SHRINK-VECTOR.
 102   (fill-pointer :type index
 103                 :ref-trans %array-fill-pointer
 104                 :ref-known (flushable foldable)
 105                 :set-trans (setf %array-fill-pointer)
 106                 :set-known (unsafe))
 107   (fill-pointer-p :type (member t nil)
 108                   :ref-trans %array-fill-pointer-p
 109                   :ref-known (flushable foldable)
 110                   :set-trans (setf %array-fill-pointer-p)
 111                   :set-known (unsafe))
 112   (elements :type index
 113             :ref-trans %array-available-elements
 114             :ref-known (flushable foldable)
 115             :set-trans (setf %array-available-elements)
 116             :set-known (unsafe))
 117   (data :type array
 118         :ref-trans %array-data-vector
 119         :ref-known (flushable foldable)
 120         :set-trans (setf %array-data-vector)
 121         :set-known (unsafe))
 122   (displacement :type (or index null)
 123                 :ref-trans %array-displacement
 124                 :ref-known (flushable foldable)
 125                 :set-trans (setf %array-displacement)
 126                 :set-known (unsafe))
 127   (displaced-p :type (member t nil)
 128                :ref-trans %array-displaced-p
 129                :ref-known (flushable foldable)
 130                :set-trans (setf %array-displaced-p)
 131                :set-known (unsafe))
 132   (dimensions :rest-p t))
 133
 134 (define-primitive-object (vector :type vector
 135                                  :lowtag other-pointer-lowtag
 136                                  :widetag t)
 137   ;; FILL-POINTER of an ARRAY is in the same place as LENGTH of a
 138   ;; VECTOR -- see SHRINK-VECTOR.
 139   (length :ref-trans sb!c::vector-length
 140           :type index)
 141   (data :rest-p t :c-type #!-alpha "unsigned long" #!+alpha "u32"))
 142
 143 (define-primitive-object (code :type code-component
 144                                :lowtag other-pointer-lowtag
 145                                :widetag t)
 146   (code-size :type index
 147              :ref-known (flushable movable)
 148              :ref-trans %code-code-size)
 149   (entry-points :type (or function null)
 150                 :ref-known (flushable)
 151                 :ref-trans %code-entry-points
 152                 :set-known (unsafe)
 153                 :set-trans (setf %code-entry-points))
 154   (debug-info :type t
 155               :ref-known (flushable)
 156               :ref-trans %code-debug-info
 157               :set-known (unsafe)
 158               :set-trans (setf %code-debug-info))
 159   (trace-table-offset)
 160   (constants :rest-p t))
 161
 162 (define-primitive-object (fdefn :type fdefn
 163                                 :lowtag other-pointer-lowtag
 164                                 :widetag fdefn-widetag)
 165   (name :ref-trans fdefn-name)
 166   (fun :type (or function null) :ref-trans fdefn-fun)
 167   (raw-addr :c-type #!-alpha "char *" #!+alpha "u32"))
 168
 169 ;;; a simple function (as opposed to hairier things like closures
 170 ;;; which are also subtypes of Common Lisp's FUNCTION type)
 171 (define-primitive-object (simple-fun :type function
 172                                      :lowtag fun-pointer-lowtag
 173                                      :widetag simple-fun-header-widetag)
 174   #!-(or x86 x86-64) (self :ref-trans %simple-fun-self
 175                :set-trans (setf %simple-fun-self))
 176   #!+(or x86 x86-64) (self
 177           ;; KLUDGE: There's no :SET-KNOWN, :SET-TRANS, :REF-KNOWN, or
 178           ;; :REF-TRANS here in this case. Instead, there's separate
 179           ;; DEFKNOWN/DEFINE-VOP/DEFTRANSFORM stuff in
 180           ;; compiler/x86/system.lisp to define and declare them by
 181           ;; hand. I don't know why this is, but that's (basically)
 182           ;; the way it was done in CMU CL, and it works. (It's not
 183           ;; exactly the same way it was done in CMU CL in that CMU
 184           ;; CL's allows duplicate DEFKNOWNs, blithely overwriting any
 185           ;; previous data associated with the previous DEFKNOWN, and
 186           ;; that property was used to mask the definitions here. In
 187           ;; SBCL as of 0.6.12.64 that's not allowed -- too confusing!
 188           ;; -- so we have to explicitly suppress the DEFKNOWNish
 189           ;; stuff here in order to allow this old hack to work in the
 190           ;; new world. -- WHN 2001-08-82
 191           )
 192   (next :type (or function null)
 193         :ref-known (flushable)
 194         :ref-trans %simple-fun-next
 195         :set-known (unsafe)
 196         :set-trans (setf %simple-fun-next))
 197   (name :ref-known (flushable)
 198         :ref-trans %simple-fun-name
 199         :set-known (unsafe)
 200         :set-trans (setf %simple-fun-name))
 201   (arglist :type list
 202            :ref-known (flushable)
 203            :ref-trans %simple-fun-arglist
 204            :set-known (unsafe)
 205            :set-trans (setf %simple-fun-arglist))
 206   (type :ref-known (flushable)
 207         :ref-trans %simple-fun-type
 208         :set-known (unsafe)
 209         :set-trans (setf %simple-fun-type))
 210   ;; the SB!C::DEBUG-FUN object corresponding to this object, or NIL for none
 211   #+nil ; FIXME: doesn't work (gotcha, lowly maintenoid!) See notes on bug 137.
 212   (debug-fun :ref-known (flushable)
 213              :ref-trans %simple-fun-debug-fun
 214              :set-known (unsafe)
 215              :set-trans (setf %simple-fun-debug-fun))
 216   (code :rest-p t :c-type "unsigned char"))
 217
 218 (define-primitive-object (return-pc :lowtag other-pointer-lowtag :widetag t)
 219   (return-point :c-type "unsigned char" :rest-p t))
 220
 221 (define-primitive-object (closure :lowtag fun-pointer-lowtag
 222                                   :widetag closure-header-widetag)
 223   (fun :init :arg :ref-trans %closure-fun)
 224   ;; This SELF slot needs explanation.
 225   ;;
 226   ;; Ordinary closures did not need this slot before version 0.9.3.xx,
 227   ;; as the closure object was already in some dedicated register --
 228   ;; EAX/RAX on x86(-64), reg_LEXENV on register-rich platforms -- and
 229   ;; consequently setting up the environment (from the INFO slot,
 230   ;; below) was easy.
 231   ;;
 232   ;; However, it is not easy to support calling FUNCALLABLE-INSTANCEs
 233   ;; in the same way; in a FUNCALLABLE-INSTANCE, there are
 234   ;; conceptually two variable-length data areas: the closure
 235   ;; environment, if any, and the slots of the instance.
 236   ;;
 237   ;; Until sbcl-0.9.3.xx, it was required that closures to be set as a
 238   ;; FUNCALLABLE-INSTANCE-FUNCTION be defined using the magical
 239   ;; keyword SB-KERNEL:INSTANCE-LAMBDA, rather than ordinary LAMBDA;
 240   ;; this caused an extra indirection to be compiled into the closure
 241   ;; code to load the closure from the FUNCALLABLE-INSTANCE-LEXENV
 242   ;; slot before setting up the environment for the function body.
 243   ;; Failure to obey this protocol yielded confusing error messages as
 244   ;; either INSTANCE-LAMBDAs tried to dereference environments that
 245   ;; weren't there, or ordinary LAMBDAs got hold of the LAYOUT and
 246   ;; LEXENV slots of a FUNCALLABLE-INSTANCE.
 247   ;;
 248   ;; By adding this SELF slot, which is at the same offset in a
 249   ;; regular CLOSURE as the LEXENV slot is in a FUNCALLABLE-INSTANCE,
 250   ;; we enable the extra indirection (VOP FUNCALLABLE-INSTANCE-LEXENV,
 251   ;; in src/compiler/ir2tran.lisp) to be compiled unconditionally
 252   ;; (provided that we set this slot to the closure object itself).
 253   ;; Relative to the code before, this adds a word to the space
 254   ;; requirements of a closure, and one instruction (a memory fetch)
 255   ;; to the body of a closure function.
 256   ;;
 257   ;; There are potentially other implementation strategies which would
 258   ;; remove the need for this extra indirection in regular closures,
 259   ;; such as setting up a trampoline for funcallable instances (though
 260   ;; it was not clear to me that there are enough registers free in
 261   ;; the x86 backend to permit this).  This indirection should not be
 262   ;; too disastrous, given that for regular closures the fetch is from
 263   ;; memory which is known to be active.
 264   ;;
 265   ;; CSR, 2005-08-05
 266   (self) ; KLUDGE (see above comment)
 267   (info :rest-p t))
 268
 269 (define-primitive-object (funcallable-instance
 270                           :lowtag fun-pointer-lowtag
 271                           :widetag funcallable-instance-header-widetag
 272                           :alloc-trans %make-funcallable-instance)
 273   #!-(or x86 x86-64)
 274   (fun
 275    :ref-known (flushable) :ref-trans %funcallable-instance-fun
 276    :set-known (unsafe) :set-trans (setf %funcallable-instance-fun))
 277   #!+(or x86 x86-64)
 278   (fun
 279    :ref-known (flushable) :ref-trans %funcallable-instance-fun
 280    ;; KLUDGE: There's no :SET-KNOWN or :SET-TRANS in this case.
 281    ;; Instead, later in compiler/x86/system.lisp there's a separate
 282    ;; DEFKNOWN for (SETF %FUNCALLABLE-INSTANCE-FUN), and a weird
 283    ;; unexplained DEFTRANSFORM from (SETF %SIMPLE-FUN-INSTANCE-FUN)
 284    ;; into (SETF %SIMPLE-FUN-SELF). The #!+X86 wrapped around this case
 285    ;; is a literal translation of the old CMU CL implementation into
 286    ;; the new world of sbcl-0.6.12.63, where multiple DEFKNOWNs for
 287    ;; the same operator cause an error (instead of silently deleting
 288    ;; all information associated with the old DEFKNOWN, as before).
 289    ;; It's definitely not very clean, with too many #!+ conditionals and
 290    ;; too little documentation, but I have more urgent things to
 291    ;; clean up right now, so I've just left it as a literal
 292    ;; translation without trying to fix it. -- WHN 2001-08-02
 293    )
 294   (lexenv :ref-known (flushable) :ref-trans %funcallable-instance-lexenv
 295           :set-known (unsafe) :set-trans (setf %funcallable-instance-lexenv))
 296   (info :rest-p t))
 297
 298 (define-primitive-object (value-cell :lowtag other-pointer-lowtag
 299                                      :widetag value-cell-header-widetag
 300                                      :alloc-trans make-value-cell)
 301   (value :set-trans value-cell-set
 302          :set-known (unsafe)
 303          :ref-trans value-cell-ref
 304          :ref-known (flushable)
 305          :init :arg))
 306
 307 #!+alpha
 308 (define-primitive-object (sap :lowtag other-pointer-lowtag
 309                               :widetag sap-widetag)
 310   (padding)
 311   (pointer :c-type "char *" :length 2))
 312
 313 #!-alpha
 314 (define-primitive-object (sap :lowtag other-pointer-lowtag
 315                               :widetag sap-widetag)
 316   (pointer :c-type "char *"))
 317
 318
 319 (define-primitive-object (weak-pointer :type weak-pointer
 320                                        :lowtag other-pointer-lowtag
 321                                        :widetag weak-pointer-widetag
 322                                        :alloc-trans make-weak-pointer)
 323   (value :ref-trans sb!c::%weak-pointer-value :ref-known (flushable)
 324          :init :arg)
 325   (broken :type (member t nil)
 326           :ref-trans sb!c::%weak-pointer-broken :ref-known (flushable)
 327           :init :null)
 328   (next :c-type #!-alpha "struct weak_pointer *" #!+alpha "u32"))
 329
 330 ;;;; other non-heap data blocks
 331
 332 (define-primitive-object (binding)
 333   value
 334   symbol)
 335
 336 (define-primitive-object (unwind-block)
 337   (current-uwp :c-type #!-alpha "struct unwind_block *" #!+alpha "u32")
 338   (current-cont :c-type #!-alpha "lispobj *" #!+alpha "u32")
 339   #!-(or x86 x86-64) current-code
 340   entry-pc)
 341
 342 (define-primitive-object (catch-block)
 343   (current-uwp :c-type #!-alpha "struct unwind_block *" #!+alpha "u32")
 344   (current-cont :c-type #!-alpha "lispobj *" #!+alpha "u32")
 345   #!-(or x86 x86-64) current-code
 346   entry-pc
 347   tag
 348   (previous-catch :c-type #!-alpha "struct catch_block *" #!+alpha "u32")
 349   size)
 350
 351 ;;; (For an explanation of this, see the comments at the definition of
 352 ;;; KLUDGE-NONDETERMINISTIC-CATCH-BLOCK-SIZE.)
 353 (aver (= kludge-nondeterministic-catch-block-size catch-block-size))
 354 \f
 355 ;;;; symbols
 356
 357 (define-primitive-object (symbol :lowtag other-pointer-lowtag
 358                                  :widetag symbol-header-widetag
 359                                  :alloc-trans make-symbol)
 360
 361   ;; Beware when changing this definition.  NIL-the-symbol is defined
 362   ;; using this layout, and NIL-the-end-of-list-marker is the cons
 363   ;; ( NIL . NIL ), living in the first two slots of NIL-the-symbol
 364   ;; (conses have no header).  Careful selection of lowtags ensures
 365   ;; that the same pointer can be used for both purposes:
 366   ;; OTHER-POINTER-LOWTAG is 7, LIST-POINTER-LOWTAG is 3, so if you
 367   ;; subtract 3 from (SB-KERNEL:GET-LISP-OBJ-ADDRESS 'NIL) you get the
 368   ;; first data slot, and if you subtract 7 you get a symbol header.
 369
 370   ;; also the CAR of NIL-as-end-of-list
 371   (value :init :unbound :ref-known (flushable) :ref-trans symbol-global-value)
 372   ;; also the CDR of NIL-as-end-of-list.  Its reffer needs special
 373   ;; care for this reason, as hash values must be fixnums.
 374   (hash :set-trans %set-symbol-hash)
 375
 376   (plist :ref-trans symbol-plist
 377          :set-trans %set-symbol-plist
 378          :init :null)
 379   (name :ref-trans symbol-name :init :arg)
 380   (package :ref-trans symbol-package
 381            :set-trans %set-symbol-package
 382            :init :null)
 383   #!+sb-thread (tls-index :ref-known (flushable) :ref-trans symbol-tls-index))
 384
 385 (define-primitive-object (complex-single-float
 386                           :lowtag other-pointer-lowtag
 387                           :widetag complex-single-float-widetag)
 388   (real :c-type "float")
 389   (imag :c-type "float"))
 390
 391 (define-primitive-object (complex-double-float
 392                           :lowtag other-pointer-lowtag
 393                           :widetag complex-double-float-widetag)
 394   #!-x86-64 (filler)
 395   (real :c-type "double" :length #!-x86-64 2 #!+x86-64 1)
 396   (imag :c-type "double" :length #!-x86-64 2 #!+x86-64 1))
 397
 398 ;;; this isn't actually a lisp object at all, it's a c structure that lives
 399 ;;; in c-land.  However, we need sight of so many parts of it from Lisp that
 400 ;;; it makes sense to define it here anyway, so that the GENESIS machinery
 401 ;;; can take care of maintaining Lisp and C versions.
 402 ;;; Hence the even-fixnum lowtag just so we don't get odd(sic) numbers
 403 ;;; added to the slot offsets
 404 (define-primitive-object (thread :lowtag even-fixnum-lowtag)
 405   ;; no_tls_value_marker is borrowed very briefly at thread startup to
 406   ;; pass the address of initial-function into new_thread_trampoline.
 407   ;; tls[0] = NO_TLS_VALUE_MARKER_WIDETAG because a the tls index slot
 408   ;; of a symbol is initialized to zero
 409   (no-tls-value-marker)
 410   (os-thread :c-type "volatile os_thread_t")
 411   (binding-stack-start :c-type "lispobj *" :length #!+alpha 2 #!-alpha 1)
 412   (binding-stack-pointer :c-type "lispobj *" :length #!+alpha 2 #!-alpha 1)
 413   (control-stack-start :c-type "lispobj *" :length #!+alpha 2 #!-alpha 1)
 414   (control-stack-end :c-type "lispobj *" :length #!+alpha 2 #!-alpha 1)
 415   (alien-stack-start :c-type "lispobj *" :length #!+alpha 2 #!-alpha 1)
 416   (alien-stack-pointer :c-type "lispobj *" :length #!+alpha 2 #!-alpha 1)
 417   #!+gencgc (alloc-region :c-type "struct alloc_region" :length 5)
 418   (this :c-type "struct thread *" :length #!+alpha 2 #!-alpha 1)
 419   (prev :c-type "struct thread *" :length #!+alpha 2 #!-alpha 1)
 420   (next :c-type "struct thread *" :length #!+alpha 2 #!-alpha 1)
 421   ;; starting, running, suspended, dead
 422   (state :c-type "volatile lispobj")
 423   (tls-cookie)                          ;  on x86, the LDT index
 424   #!+(or x86 x86-64) (pseudo-atomic-atomic)
 425   #!+(or x86 x86-64) (pseudo-atomic-interrupted)
 426   (interrupt-data :c-type "struct interrupt_data *"
 427                   :length #!+alpha 2 #!-alpha 1)
 428   (interrupt-contexts :c-type "os_context_t *" :rest-p t))