src/code/cross-misc.lisp

   1 ;;;; cross-compile-time-only replacements for miscellaneous unportable
   2 ;;;; stuff
   3
   4 ;;;; This software is part of the SBCL system. See the README file for
   5 ;;;; more information.
   6 ;;;;
   7 ;;;; This software is derived from the CMU CL system, which was
   8 ;;;; written at Carnegie Mellon University and released into the
   9 ;;;; public domain. The software is in the public domain and is
  10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  11 ;;;; files for more information.
  12
  13 (in-package "SB!IMPL")
  14
  15 ;;; In correct code, TRULY-THE has only a performance impact and can
  16 ;;; be safely degraded to ordinary THE.
  17 (defmacro truly-the (type expr)
  18   `(the ,type ,expr))
  19
  20 ;;; MAYBE-INLINE and FREEZE-TYPE declarations can be safely ignored
  21 ;;; (possibly at some cost in efficiency).
  22 (declaim (declaration freeze-type maybe-inline))
  23
  24 ;;; INHIBIT-WARNINGS declarations can be safely ignored (although we
  25 ;;; may then have to wade through some irrelevant warnings).
  26 (declaim (declaration inhibit-warnings))
  27
  28 ;;; Interrupt control isn't an issue in the cross-compiler: we don't
  29 ;;; use address-dependent (and thus GC-dependent) hashes, and we only
  30 ;;; have a single thread of control.
  31 (defmacro without-interrupts (&rest forms)
  32   `(macrolet ((allow-with-interrupts (&body body)
  33                 `(progn ,@body))
  34               (with-local-interrupts (&body body)
  35                 `(progn ,@body)))
  36      ,@forms))
  37
  38 ;;; The GENESIS function works with fasl code which would, in the
  39 ;;; target SBCL, work on ANSI-STREAMs (streams which aren't extended
  40 ;;; Gray streams). In ANSI Common Lisp, an ANSI-STREAM is just a
  41 ;;; CL:STREAM.
  42 (deftype ansi-stream () 'stream)
  43
  44 (deftype sb!kernel:instance ()
  45   '(or condition structure-object standard-object))
  46 (deftype sb!kernel:funcallable-instance ()
  47   (error "not clear how to represent FUNCALLABLE-INSTANCE type"))
  48
  49 ;;; In the target SBCL, the INSTANCE type refers to a base
  50 ;;; implementation for compound types with lowtag
  51 ;;; INSTANCE-POINTER-LOWTAG. There's no way to express exactly that
  52 ;;; concept portably, but we can get essentially the same effect by
  53 ;;; testing for any of the standard types which would, in the target
  54 ;;; SBCL, be derived from INSTANCE:
  55 (defun %instancep (x)
  56   (typep x '(or condition structure-object standard-object)))
  57
  58 ;;; There aren't any FUNCALLABLE-INSTANCEs in the cross-compilation
  59 ;;; host Common Lisp.
  60 (defun funcallable-instance-p (x)
  61   (if (typep x 'generic-function)
  62     ;; In the target SBCL, FUNCALLABLE-INSTANCEs are used to implement
  63     ;; generic functions, so any case which tests for this might in
  64     ;; fact be trying to test for generic functions. My (WHN 19990313)
  65     ;; expectation is that this case won't arise in the
  66     ;; cross-compiler, but if it does, it deserves a little thought,
  67     ;; rather than reflexively returning NIL.
  68     (error "not clear how to handle GENERIC-FUNCTION")
  69     nil))
  70
  71 ;;; This seems to be the portable Common Lisp type test which
  72 ;;; corresponds to the effect of the target SBCL implementation test...
  73 (defun sb!kernel:array-header-p (x)
  74   (and (typep x 'array)
  75        (or (not (typep x 'simple-array))
  76            (/= (array-rank x) 1))))
  77
  78 ;;; GENESIS needs these at cross-compile time. The target
  79 ;;; implementation of these is reasonably efficient by virtue of its
  80 ;;; ability to peek into the internals of the package implementation;
  81 ;;; this reimplementation is portable but slow.
  82 (defun package-internal-symbol-count (package)
  83   (let ((result 0))
  84     (declare (type fixnum result))
  85     (do-symbols (i package)
  86       ;; KLUDGE: The ANSI Common Lisp specification warns that
  87       ;; DO-SYMBOLS may execute its body more than once for symbols
  88       ;; that are inherited from multiple packages, and we currently
  89       ;; make no attempt to correct for that here. (The current uses
  90       ;; of this function at cross-compile time don't really care if
  91       ;; the count is a little too high.) -- WHN 19990826
  92       (multiple-value-bind (symbol status)
  93           (find-symbol (symbol-name i) package)
  94         (declare (ignore symbol))
  95         (when (member status '(:internal :inherited))
  96           (incf result))))
  97     result))
  98 (defun package-external-symbol-count (package)
  99   (let ((result 0))
 100     (declare (type fixnum result))
 101     (do-external-symbols (i package)
 102       (declare (ignorable i))
 103       (incf result))
 104     result))
 105
 106 ;;; In the target Lisp, INTERN* is the primitive and INTERN is
 107 ;;; implemented in terms of it. This increases efficiency by letting
 108 ;;; us reuse a fixed-size buffer; the alternative would be
 109 ;;; particularly painful because we don't implement DYNAMIC-EXTENT. In
 110 ;;; the host Lisp, this is only used at cold load time, and we don't
 111 ;;; care as much about efficiency, so it's fine to treat the host
 112 ;;; Lisp's INTERN as primitive and implement INTERN* in terms of it.
 113 (defun intern* (nameoid length package)
 114   (intern (replace (make-string length) nameoid :end2 length) package))
 115
 116 ;;; In the target Lisp this is implemented by reading a fixed slot in
 117 ;;; the symbol. In portable ANSI Common Lisp the same criteria can be
 118 ;;; met (more slowly, and with the extra property of repeatability
 119 ;;; between runs) by just calling SXHASH.
 120 (defun symbol-hash (symbol)
 121   (declare (type symbol symbol))
 122   (sxhash symbol))
 123
 124 ;;; These functions are needed for constant-folding.
 125 (defun sb!kernel:simple-array-nil-p (object)
 126   (when (typep object 'array)
 127     (assert (not (eq (array-element-type object) nil))))
 128   nil)
 129
 130 (defun sb!kernel:%negate (number)
 131   (- number))
 132
 133 (defun sb!kernel:%single-float (number)
 134   (coerce number 'single-float))
 135
 136 (defun sb!kernel:%double-float (number)
 137   (coerce number 'double-float))
 138
 139 (defun sb!kernel:%ldb (size posn integer)
 140   (ldb (byte size posn) integer))
 141
 142 (defun sb!kernel:%dpb (newbyte size posn integer)
 143   (dpb newbyte (byte size posn) integer))
 144
 145 (defun sb!kernel:%with-array-data (array start end)
 146   (assert (typep array '(simple-array * (*))))
 147   (values array start end 0))
 148
 149 (defun sb!kernel:signed-byte-32-p (number)
 150   (typep number '(signed-byte 32)))
 151
 152 ;;; package locking nops for the cross-compiler
 153
 154 (defmacro without-package-locks (&body body)
 155   `(progn ,@body))
 156
 157 (defmacro with-single-package-locked-error ((&optional kind thing &rest format)
 158                                             &body body)
 159   (declare (ignore kind thing format))
 160   `(progn ,@body))
 161
 162 (defun program-assert-symbol-home-package-unlocked (context symbol control)
 163   (declare (ignore context control))
 164   symbol)
 165
 166 (defun assert-package-unlocked (package &optional control &rest args)
 167   (declare (ignore control args))
 168   package)
 169
 170 (defun assert-symbol-home-package-unlocked (name format &key continuablep)
 171   (declare (ignore format continuablep))
 172   name)
 173
 174 (declaim (declaration enable-package-locks disable-package-locks))