src/code/target-alieneval.lisp

   1 ;;;; This file contains parts of the ALIEN implementation that
   2 ;;;; are not part of the compiler.
   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!ALIEN")
  14
  15 (/show0 "target-alieneval.lisp 15")
  16 \f
  17 ;;;; alien variables
  18
  19 ;;; Make a string out of the symbol, converting all uppercase letters to
  20 ;;; lower case and hyphens into underscores.
  21 (eval-when (:compile-toplevel :load-toplevel :execute)
  22   (defun guess-alien-name-from-lisp-name (lisp-name)
  23     (declare (type symbol lisp-name))
  24     (nsubstitute #\_ #\- (string-downcase (symbol-name lisp-name)))))
  25
  26 ;;; The opposite of GUESS-ALIEN-NAME-FROM-LISP-NAME. Make a symbol out
  27 ;;; of the string, converting all lowercase letters to uppercase and
  28 ;;; underscores into hyphens.
  29 (eval-when (:compile-toplevel :load-toplevel :execute)
  30   (defun guess-lisp-name-from-alien-name (alien-name)
  31     (declare (type simple-string alien-name))
  32     (intern (nsubstitute #\- #\_ (string-upcase alien-name)))))
  33
  34 ;;; Extract the Lisp and alien names from NAME. If only one is given,
  35 ;;; guess the other.
  36 (eval-when (:compile-toplevel :load-toplevel :execute)
  37   (defun pick-lisp-and-alien-names (name)
  38     (etypecase name
  39       (string
  40        (values (guess-lisp-name-from-alien-name name) name))
  41       (symbol
  42        (values name (guess-alien-name-from-lisp-name name)))
  43       (list
  44        (unless (proper-list-of-length-p name 2)
  45          (error "badly formed alien name"))
  46        (values (cadr name) (car name))))))
  47
  48 (defmacro define-alien-variable (name type &environment env)
  49   #!+sb-doc
  50   "Define NAME as an external alien variable of type TYPE. NAME should be
  51    a list of a string holding the alien name and a symbol to use as the Lisp
  52    name. If NAME is just a symbol or string, then the other name is guessed
  53    from the one supplied."
  54   (multiple-value-bind (lisp-name alien-name) (pick-lisp-and-alien-names name)
  55     (with-auxiliary-alien-types env
  56       (let ((alien-type (parse-alien-type type env)))
  57         `(eval-when (:compile-toplevel :load-toplevel :execute)
  58            ,@(when *new-auxiliary-types*
  59                `((%def-auxiliary-alien-types ',*new-auxiliary-types*)))
  60            (%define-alien-variable ',lisp-name
  61                                    ',alien-name
  62                                    ',alien-type))))))
  63
  64 ;;; Do the actual work of DEFINE-ALIEN-VARIABLE.
  65 (eval-when (:compile-toplevel :load-toplevel :execute)
  66   (defun %define-alien-variable (lisp-name alien-name type)
  67     (setf (info :variable :kind lisp-name) :alien)
  68     (setf (info :variable :where-from lisp-name) :defined)
  69     (clear-info :variable :constant-value lisp-name)
  70     (setf (info :variable :alien-info lisp-name)
  71           (make-heap-alien-info :type type
  72                                 :sap-form `(foreign-symbol-sap ',alien-name t)))))
  73
  74 (defmacro extern-alien (name type &environment env)
  75   #!+sb-doc
  76   "Access the alien variable named NAME, assuming it is of type TYPE. This
  77    is SETFable."
  78   (let* ((alien-name (etypecase name
  79                        (symbol (guess-alien-name-from-lisp-name name))
  80                        (string name)))
  81          (alien-type (parse-alien-type type env))
  82          (datap (not (alien-fun-type-p alien-type))))
  83     `(%heap-alien ',(make-heap-alien-info
  84                      :type alien-type
  85                      :sap-form `(foreign-symbol-sap ',alien-name ,datap)))))
  86
  87 (defmacro with-alien (bindings &body body &environment env)
  88   #!+sb-doc
  89   "Establish some local alien variables. Each BINDING is of the form:
  90      VAR TYPE [ ALLOCATION ] [ INITIAL-VALUE | EXTERNAL-NAME ]
  91    ALLOCATION should be one of:
  92      :LOCAL (the default)
  93        The alien is allocated on the stack, and has dynamic extent.
  94      :STATIC
  95        The alien is allocated on the heap, and has infinite extent. The alien
  96        is allocated at load time, so the same piece of memory is used each time
  97        this form executes.
  98      :EXTERN
  99        No alien is allocated, but VAR is established as a local name for
 100        the external alien given by EXTERNAL-NAME."
 101   (/show "entering WITH-ALIEN" bindings)
 102   (with-auxiliary-alien-types env
 103     (dolist (binding (reverse bindings))
 104       (/show binding)
 105       (destructuring-bind
 106           (symbol type &optional (opt1 nil opt1p) (opt2 nil opt2p))
 107           binding
 108         (/show symbol type opt1 opt2)
 109         (let* ((alien-type (parse-alien-type type env))
 110                (datap (not (alien-fun-type-p alien-type))))
 111           (/show alien-type)
 112           (multiple-value-bind (allocation initial-value)
 113               (if opt2p
 114                   (values opt1 opt2)
 115                   (case opt1
 116                     (:extern
 117                      (values opt1 (guess-alien-name-from-lisp-name symbol)))
 118                     (:static
 119                      (values opt1 nil))
 120                     (t
 121                      (values :local opt1))))
 122             (/show allocation initial-value)
 123             (setf body
 124                   (ecase allocation
 125                     #+nil
 126                     (:static
 127                      (let ((sap
 128                             (make-symbol (concatenate 'string "SAP-FOR-"
 129                                                       (symbol-name symbol)))))
 130                        `((let ((,sap (load-time-value (%make-alien ...))))
 131                            (declare (type system-area-pointer ,sap))
 132                            (symbol-macrolet
 133                             ((,symbol (sap-alien ,sap ,type)))
 134                             ,@(when initial-value
 135                                 `((setq ,symbol ,initial-value)))
 136                             ,@body)))))
 137                     (:extern
 138                      (/show0 ":EXTERN case")
 139                      (let ((info (make-heap-alien-info
 140                                   :type alien-type
 141                                   :sap-form `(foreign-symbol-sap ',initial-value
 142                                                                  ,datap))))
 143                        `((symbol-macrolet
 144                           ((,symbol (%heap-alien ',info)))
 145                           ,@body))))
 146                     (:local
 147                      (/show0 ":LOCAL case")
 148                      (let ((var (gensym))
 149                            (initval (if initial-value (gensym)))
 150                            (info (make-local-alien-info :type alien-type)))
 151                        (/show var initval info)
 152                        `((let ((,var (make-local-alien ',info))
 153                                ,@(when initial-value
 154                                    `((,initval ,initial-value))))
 155                            (note-local-alien-type ',info ,var)
 156                            (multiple-value-prog1
 157                                (symbol-macrolet
 158                                 ((,symbol (local-alien ',info ,var)))
 159                                 ,@(when initial-value
 160                                     `((setq ,symbol ,initval)))
 161                                 ,@body)
 162                                (dispose-local-alien ',info ,var))))))))))))
 163     (/show "revised" body)
 164     (verify-local-auxiliaries-okay)
 165     (/show0 "back from VERIFY-LOCAL-AUXILIARIES-OK, returning")
 166     `(symbol-macrolet ((&auxiliary-type-definitions&
 167                         ,(append *new-auxiliary-types*
 168                                  (auxiliary-type-definitions env))))
 169        ,@body)))
 170 \f
 171 ;;;; runtime C values that don't correspond directly to Lisp types
 172
 173 ;;; Note: The DEFSTRUCT for ALIEN-VALUE lives in a separate file
 174 ;;; 'cause it has to be real early in the cold-load order.
 175 #!-sb-fluid (declaim (freeze-type alien-value))
 176 (def!method print-object ((value alien-value) stream)
 177   (print-unreadable-object (value stream)
 178     (format stream
 179             "~S ~S #X~8,'0X ~S ~S"
 180             'alien-value
 181             :sap (sap-int (alien-value-sap value))
 182             :type (unparse-alien-type (alien-value-type value)))))
 183
 184 #!-sb-fluid (declaim (inline null-alien))
 185 (defun null-alien (x)
 186   #!+sb-doc
 187   "Return true if X (which must be an ALIEN pointer) is null, false otherwise."
 188   (zerop (sap-int (alien-sap x))))
 189
 190 (defmacro sap-alien (sap type &environment env)
 191   #!+sb-doc
 192   "Convert the system area pointer SAP to an ALIEN of the specified TYPE (not
 193    evaluated.) TYPE must be pointer-like."
 194   (let ((alien-type (parse-alien-type type env)))
 195     (if (eq (compute-alien-rep-type alien-type) 'system-area-pointer)
 196         `(%sap-alien ,sap ',alien-type)
 197         (error "cannot make an alien of type ~S out of a SAP" type))))
 198
 199 (defun %sap-alien (sap type)
 200   (declare (type system-area-pointer sap)
 201            (type alien-type type))
 202   (make-alien-value :sap sap :type type))
 203
 204 (defun alien-sap (alien)
 205   #!+sb-doc
 206   "Return a System-Area-Pointer pointing to Alien's data."
 207   (declare (type alien-value alien))
 208   (alien-value-sap alien))
 209 \f
 210 ;;;; allocation/deallocation of heap aliens
 211
 212 (defmacro make-alien (type &optional size &environment env)
 213   #!+sb-doc
 214   "Allocate an alien of type TYPE and return an alien pointer to it. If SIZE
 215 is supplied, how it is interpreted depends on TYPE. If TYPE is an array type,
 216 SIZE is used as the first dimension for the allocated array. If TYPE is not an
 217 array, then SIZE is the number of elements to allocate. The memory is
 218 allocated using ``malloc'', so it can be passed to foreign functions which use
 219 ``free''."
 220   (let ((alien-type (if (alien-type-p type)
 221                         type
 222                         (parse-alien-type type env))))
 223     (multiple-value-bind (size-expr element-type)
 224         (if (alien-array-type-p alien-type)
 225             (let ((dims (alien-array-type-dimensions alien-type)))
 226               (cond
 227                 (size
 228                  (unless dims
 229                    (error
 230                     "cannot override the size of zero-dimensional arrays"))
 231                  (when (constantp size)
 232                    (setf alien-type (copy-alien-array-type alien-type))
 233                    (setf (alien-array-type-dimensions alien-type)
 234                          (cons (constant-form-value size) (cdr dims)))))
 235                 (dims
 236                  (setf size (car dims)))
 237                 (t
 238                  (setf size 1)))
 239               (values `(* ,size ,@(cdr dims))
 240                       (alien-array-type-element-type alien-type)))
 241             (values (or size 1) alien-type))
 242       (let ((bits (alien-type-bits element-type))
 243             (alignment (alien-type-alignment element-type)))
 244         (unless bits
 245           (error "The size of ~S is unknown."
 246                  (unparse-alien-type element-type)))
 247         (unless alignment
 248           (error "The alignment of ~S is unknown."
 249                  (unparse-alien-type element-type)))
 250         ;; This is the one place where the %SAP-ALIEN note is quite
 251         ;; undesirable, in most uses of MAKE-ALIEN the %SAP-ALIEN
 252         ;; cannot be optimized away.
 253         `(locally (declare (muffle-conditions compiler-note))
 254            (%sap-alien (%make-alien (* ,(align-offset bits alignment)
 255                                        ,size-expr))
 256                        ',(make-alien-pointer-type :to alien-type)))))))
 257
 258 ;;; Allocate a block of memory at least BITS bits long and return a
 259 ;;; system area pointer to it.
 260 #!-sb-fluid (declaim (inline %make-alien))
 261 (defun %make-alien (bits)
 262   (declare (type index bits))
 263   (alien-funcall (extern-alien "malloc"
 264                                (function system-area-pointer unsigned))
 265                  (ash (the index (+ bits 7)) -3)))
 266
 267 #!-sb-fluid (declaim (inline free-alien))
 268 (defun free-alien (alien)
 269   #!+sb-doc
 270   "Dispose of the storage pointed to by ALIEN. ALIEN must have been allocated
 271    by MAKE-ALIEN or malloc(3)."
 272   (alien-funcall (extern-alien "free" (function (values) system-area-pointer))
 273                  (alien-sap alien))
 274   nil)
 275 \f
 276 ;;;; the SLOT operator
 277
 278 ;;; Find the field named SLOT, or die trying.
 279 (defun slot-or-lose (type slot)
 280   (declare (type alien-record-type type)
 281            (type symbol slot))
 282   (or (find slot (alien-record-type-fields type)
 283             :key #'alien-record-field-name)
 284       (error "There is no slot named ~S in ~S." slot type)))
 285
 286 ;;; Extract the value from the named slot from the record ALIEN. If
 287 ;;; ALIEN is actually a pointer, then DEREF it first.
 288 (defun slot (alien slot)
 289   #!+sb-doc
 290   "Extract SLOT from the Alien STRUCT or UNION ALIEN. May be set with SETF."
 291   (declare (type alien-value alien)
 292            (type symbol slot)
 293            (optimize (inhibit-warnings 3)))
 294   (let ((type (alien-value-type alien)))
 295     (etypecase type
 296       (alien-pointer-type
 297        (slot (deref alien) slot))
 298       (alien-record-type
 299        (let ((field (slot-or-lose type slot)))
 300          (extract-alien-value (alien-value-sap alien)
 301                               (alien-record-field-offset field)
 302                               (alien-record-field-type field)))))))
 303
 304 ;;; Deposit the value in the specified slot of the record ALIEN. If
 305 ;;; the ALIEN is really a pointer, DEREF it first. The compiler uses
 306 ;;; this when it can't figure out anything better.
 307 (defun %set-slot (alien slot value)
 308   (declare (type alien-value alien)
 309            (type symbol slot)
 310            (optimize (inhibit-warnings 3)))
 311   (let ((type (alien-value-type alien)))
 312     (etypecase type
 313       (alien-pointer-type
 314        (%set-slot (deref alien) slot value))
 315       (alien-record-type
 316        (let ((field (slot-or-lose type slot)))
 317          (deposit-alien-value (alien-value-sap alien)
 318                               (alien-record-field-offset field)
 319                               (alien-record-field-type field)
 320                               value))))))
 321
 322 ;;; Compute the address of the specified slot and return a pointer to it.
 323 (defun %slot-addr (alien slot)
 324   (declare (type alien-value alien)
 325            (type symbol slot)
 326            (optimize (inhibit-warnings 3)))
 327   (let ((type (alien-value-type alien)))
 328     (etypecase type
 329       (alien-pointer-type
 330        (%slot-addr (deref alien) slot))
 331       (alien-record-type
 332        (let* ((field (slot-or-lose type slot))
 333               (offset (alien-record-field-offset field))
 334               (field-type (alien-record-field-type field)))
 335          (%sap-alien (sap+ (alien-sap alien) (/ offset sb!vm:n-byte-bits))
 336                      (make-alien-pointer-type :to field-type)))))))
 337 \f
 338 ;;;; the DEREF operator
 339
 340 ;;; This function does most of the work of the different DEREF
 341 ;;; methods. It returns two values: the type and the offset (in bits)
 342 ;;; of the referred-to alien.
 343 (defun deref-guts (alien indices)
 344   (declare (type alien-value alien)
 345            (type list indices)
 346            (values alien-type integer))
 347   (let ((type (alien-value-type alien)))
 348     (etypecase type
 349       (alien-pointer-type
 350        (when (cdr indices)
 351          (error "too many indices when DEREF'ing ~S: ~W"
 352                 type
 353                 (length indices)))
 354        (let ((element-type (alien-pointer-type-to type)))
 355          (values element-type
 356                  (if indices
 357                      (* (align-offset (alien-type-bits element-type)
 358                                       (alien-type-alignment element-type))
 359                         (car indices))
 360                      0))))
 361       (alien-array-type
 362        (unless (= (length indices) (length (alien-array-type-dimensions type)))
 363          (error "incorrect number of indices when DEREF'ing ~S: ~W"
 364                 type (length indices)))
 365        (labels ((frob (dims indices offset)
 366                   (if (null dims)
 367                       offset
 368                       (frob (cdr dims) (cdr indices)
 369                         (+ (if (zerop offset)
 370                                0
 371                                (* offset (car dims)))
 372                            (car indices))))))
 373          (let ((element-type (alien-array-type-element-type type)))
 374            (values element-type
 375                    (* (align-offset (alien-type-bits element-type)
 376                                     (alien-type-alignment element-type))
 377                       (frob (alien-array-type-dimensions type)
 378                         indices 0)))))))))
 379
 380 ;;; Dereference the alien and return the results.
 381 (defun deref (alien &rest indices)
 382   #!+sb-doc
 383   "De-reference an Alien pointer or array. If an array, the indices are used
 384    as the indices of the array element to access. If a pointer, one index can
 385    optionally be specified, giving the equivalent of C pointer arithmetic."
 386   (declare (type alien-value alien)
 387            (type list indices)
 388            (optimize (inhibit-warnings 3)))
 389   (multiple-value-bind (target-type offset) (deref-guts alien indices)
 390     (extract-alien-value (alien-value-sap alien)
 391                          offset
 392                          target-type)))
 393
 394 (defun %set-deref (alien value &rest indices)
 395   (declare (type alien-value alien)
 396            (type list indices)
 397            (optimize (inhibit-warnings 3)))
 398   (multiple-value-bind (target-type offset) (deref-guts alien indices)
 399     (deposit-alien-value (alien-value-sap alien)
 400                          offset
 401                          target-type
 402                          value)))
 403
 404 (defun %deref-addr (alien &rest indices)
 405   (declare (type alien-value alien)
 406            (type list indices)
 407            (optimize (inhibit-warnings 3)))
 408   (multiple-value-bind (target-type offset) (deref-guts alien indices)
 409     (%sap-alien (sap+ (alien-value-sap alien) (/ offset sb!vm:n-byte-bits))
 410                 (make-alien-pointer-type :to target-type))))
 411 \f
 412 ;;;; accessing heap alien variables
 413
 414 (defun %heap-alien (info)
 415   (declare (type heap-alien-info info)
 416            (optimize (inhibit-warnings 3)))
 417   (extract-alien-value (eval (heap-alien-info-sap-form info))
 418                        0
 419                        (heap-alien-info-type info)))
 420
 421 (defun %set-heap-alien (info value)
 422   (declare (type heap-alien-info info)
 423            (optimize (inhibit-warnings 3)))
 424   (deposit-alien-value (eval (heap-alien-info-sap-form info))
 425                        0
 426                        (heap-alien-info-type info)
 427                        value))
 428
 429 (defun %heap-alien-addr (info)
 430   (declare (type heap-alien-info info)
 431            (optimize (inhibit-warnings 3)))
 432   (%sap-alien (eval (heap-alien-info-sap-form info))
 433               (make-alien-pointer-type :to (heap-alien-info-type info))))
 434 \f
 435 ;;;; accessing local aliens
 436
 437 (defun make-local-alien (info)
 438   (let* ((alien (eval `(make-alien ,(local-alien-info-type info))))
 439          (alien-sap (alien-sap alien)))
 440     (finalize
 441      alien
 442      (lambda ()
 443        (alien-funcall
 444         (extern-alien "free" (function (values) system-area-pointer))
 445         alien-sap))
 446      :dont-save t)
 447     alien))
 448
 449 (defun note-local-alien-type (info alien)
 450   (declare (ignore info alien))
 451   nil)
 452
 453 (defun local-alien (info alien)
 454   (declare (ignore info))
 455   (deref alien))
 456
 457 (defun %set-local-alien (info alien value)
 458   (declare (ignore info))
 459   (setf (deref alien) value))
 460
 461 (define-setf-expander local-alien (&whole whole info alien)
 462   (let ((value (gensym))
 463         (info-var (gensym))
 464         (alloc-tmp (gensym))
 465         (info (if (and (consp info)
 466                        (eq (car info) 'quote))
 467                   (second info)
 468                   (error "Something is wrong; local-alien-info not found: ~S"
 469                          whole))))
 470     (values nil
 471             nil
 472             (list value)
 473             `(if (%local-alien-forced-to-memory-p ',info)
 474                  (%set-local-alien ',info ,alien ,value)
 475                    (let* ((,info-var ',(local-alien-info-type info))
 476                           (,alloc-tmp (deport-alloc ,value ,info-var)))
 477                      (maybe-with-pinned-objects (,alloc-tmp) (,(local-alien-info-type info))
 478                        (setf ,alien (deport ,alloc-tmp ,info-var)))))
 479             whole)))
 480
 481 (defun %local-alien-forced-to-memory-p (info)
 482   (local-alien-info-force-to-memory-p info))
 483
 484 (defun %local-alien-addr (info alien)
 485   (declare (type local-alien-info info))
 486   (unless (local-alien-info-force-to-memory-p info)
 487     (error "~S isn't forced to memory. Something went wrong." alien))
 488   alien)
 489
 490 (defun dispose-local-alien (info alien)
 491   (declare (ignore info))
 492   (cancel-finalization alien)
 493   (free-alien alien))
 494 \f
 495 ;;;; the CAST macro
 496
 497 (defmacro cast (alien type &environment env)
 498   #!+sb-doc
 499   "Convert ALIEN to an Alien of the specified TYPE (not evaluated.)  Both types
 500    must be Alien array, pointer or function types."
 501   `(%cast ,alien ',(parse-alien-type type env)))
 502
 503 (defun %cast (alien target-type)
 504   (declare (type alien-value alien)
 505            (type alien-type target-type)
 506            (optimize (safety 2))
 507            (optimize (inhibit-warnings 3)))
 508   (if (or (alien-pointer-type-p target-type)
 509           (alien-array-type-p target-type)
 510           (alien-fun-type-p target-type))
 511       (let ((alien-type (alien-value-type alien)))
 512         (if (or (alien-pointer-type-p alien-type)
 513                 (alien-array-type-p alien-type)
 514                 (alien-fun-type-p alien-type))
 515             (naturalize (alien-value-sap alien) target-type)
 516             (error "~S cannot be casted." alien)))
 517       (error "cannot cast to alien type ~S" (unparse-alien-type target-type))))
 518 \f
 519 ;;;; the ALIEN-SIZE macro
 520
 521 (defmacro alien-size (type &optional (units :bits) &environment env)
 522   #!+sb-doc
 523   "Return the size of the alien type TYPE. UNITS specifies the units to
 524    use and can be either :BITS, :BYTES, or :WORDS."
 525   (let* ((alien-type (parse-alien-type type env))
 526          (bits (alien-type-bits alien-type)))
 527     (if bits
 528         (values (ceiling bits
 529                          (ecase units
 530                            (:bits 1)
 531                            (:bytes sb!vm:n-byte-bits)
 532                            (:words sb!vm:n-word-bits))))
 533         (error "unknown size for alien type ~S"
 534                (unparse-alien-type alien-type)))))
 535 \f
 536 ;;;; NATURALIZE, DEPORT, EXTRACT-ALIEN-VALUE, DEPOSIT-ALIEN-VALUE
 537
 538 (defun coerce-to-interpreted-function (lambda-form)
 539   (let (#!+sb-eval
 540         (*evaluator-mode* :interpret))
 541     (coerce lambda-form 'function)))
 542
 543 (defun naturalize (alien type)
 544   (declare (type alien-type type))
 545   (funcall (coerce-to-interpreted-function (compute-naturalize-lambda type))
 546            alien type))
 547
 548 (defun deport (value type)
 549   (declare (type alien-type type))
 550   (funcall (coerce-to-interpreted-function (compute-deport-lambda type))
 551            value type))
 552
 553 (defun deport-alloc (value type)
 554   (declare (type alien-type type))
 555   (funcall (coerce-to-interpreted-function (compute-deport-alloc-lambda type))
 556            value type))
 557
 558 (defun extract-alien-value (sap offset type)
 559   (declare (type system-area-pointer sap)
 560            (type unsigned-byte offset)
 561            (type alien-type type))
 562   (funcall (coerce-to-interpreted-function (compute-extract-lambda type))
 563            sap offset type))
 564
 565 (defun deposit-alien-value (sap offset type value)
 566   (declare (type system-area-pointer sap)
 567            (type unsigned-byte offset)
 568            (type alien-type type))
 569   (funcall (coerce-to-interpreted-function (compute-deposit-lambda type))
 570            sap offset type value))
 571 \f
 572 ;;;; ALIEN-FUNCALL, DEFINE-ALIEN-ROUTINE
 573
 574 (defun alien-funcall (alien &rest args)
 575   #!+sb-doc
 576   "Call the foreign function ALIEN with the specified arguments. ALIEN's
 577    type specifies the argument and result types."
 578   (declare (type alien-value alien))
 579   (let ((type (alien-value-type alien)))
 580     (typecase type
 581       (alien-pointer-type
 582        (apply #'alien-funcall (deref alien) args))
 583       (alien-fun-type
 584        (unless (= (length (alien-fun-type-arg-types type))
 585                   (length args))
 586          (error "wrong number of arguments for ~S~%expected ~W, got ~W"
 587                 type
 588                 (length (alien-fun-type-arg-types type))
 589                 (length args)))
 590        (let ((stub (alien-fun-type-stub type)))
 591          (unless stub
 592            (setf stub
 593                  (let ((fun (gensym))
 594                        (parms (make-gensym-list (length args))))
 595                    (compile nil
 596                             `(lambda (,fun ,@parms)
 597                                (declare (optimize (sb!c::insert-step-conditions 0)))
 598                                (declare (type (alien ,type) ,fun))
 599                                (alien-funcall ,fun ,@parms)))))
 600            (setf (alien-fun-type-stub type) stub))
 601          (apply stub alien args)))
 602       (t
 603        (error "~S is not an alien function." alien)))))
 604
 605 (defmacro define-alien-routine (name result-type
 606                                      &rest args
 607                                      &environment lexenv)
 608   #!+sb-doc
 609   "DEFINE-ALIEN-ROUTINE Name Result-Type {(Arg-Name Arg-Type [Style])}*
 610
 611   Define a foreign interface function for the routine with the specified NAME.
 612   Also automatically DECLAIM the FTYPE of the defined function.
 613
 614   NAME may be either a string, a symbol, or a list of the form (string symbol).
 615
 616   RETURN-TYPE is the alien type for the function return value. VOID may be
 617   used to specify a function with no result.
 618
 619   The remaining forms specify individual arguments that are passed to the
 620   routine. ARG-NAME is a symbol that names the argument, primarily for
 621   documentation. ARG-TYPE is the C type of the argument. STYLE specifies the
 622   way that the argument is passed.
 623
 624   :IN
 625         An :IN argument is simply passed by value. The value to be passed is
 626         obtained from argument(s) to the interface function. No values are
 627         returned for :In arguments. This is the default mode.
 628
 629   :OUT
 630         The specified argument type must be a pointer to a fixed sized object.
 631         A pointer to a preallocated object is passed to the routine, and the
 632         the object is accessed on return, with the value being returned from
 633         the interface function. :OUT and :IN-OUT cannot be used with pointers
 634         to arrays, records or functions.
 635
 636   :COPY
 637         This is similar to :IN, except that the argument values are stored
 638         on the stack, and a pointer to the object is passed instead of
 639         the value itself.
 640
 641   :IN-OUT
 642         This is a combination of :OUT and :COPY. A pointer to the argument is
 643         passed, with the object being initialized from the supplied argument
 644         and the return value being determined by accessing the object on
 645         return."
 646   (multiple-value-bind (lisp-name alien-name)
 647       (pick-lisp-and-alien-names name)
 648     (collect ((docs) (lisp-args) (lisp-arg-types)
 649               (lisp-result-types
 650                (cond ((eql result-type 'void)
 651                       ;; What values does a function return, if it
 652                       ;; returns no values? Exactly one - NIL. -- APD,
 653                       ;; 2003-03-02
 654                       (list 'null))
 655                      (t
 656                       ;; FIXME: Check for VALUES.
 657                       (list `(alien ,result-type)))))
 658               (arg-types) (alien-vars)
 659               (alien-args) (results))
 660       (dolist (arg args)
 661         (if (stringp arg)
 662             (docs arg)
 663             (destructuring-bind (name type &optional (style :in)) arg
 664               (unless (member style '(:in :copy :out :in-out))
 665                 (error "bogus argument style ~S in ~S" style arg))
 666               (when (and (member style '(:out :in-out))
 667                          (typep (parse-alien-type type lexenv)
 668                                 'alien-pointer-type))
 669                 (error "can't use :OUT or :IN-OUT on pointer-like type:~%  ~S"
 670                        type))
 671               (let (arg-type)
 672                 (cond ((eq style :in)
 673                        (setq arg-type type)
 674                        (alien-args name))
 675                       (t
 676                        (setq arg-type `(* ,type))
 677                        (if (eq style :out)
 678                            (alien-vars `(,name ,type))
 679                            (alien-vars `(,name ,type ,name)))
 680                        (alien-args `(addr ,name))))
 681                 (arg-types arg-type)
 682                 (unless (eq style :out)
 683                   (lisp-args name)
 684                   (lisp-arg-types t
 685                                   ;; FIXME: It should be something
 686                                   ;; like `(ALIEN ,ARG-TYPE), except
 687                                   ;; for we also accept SAPs where
 688                                   ;; pointers are required.
 689                                   )))
 690               (when (or (eq style :out) (eq style :in-out))
 691                 (results name)
 692                 (lisp-result-types `(alien ,type))))))
 693       `(progn
 694          ;; The theory behind this automatic DECLAIM is that (1) if
 695          ;; you're calling C, static typing is what you're doing
 696          ;; anyway, and (2) such a declamation can be (especially for
 697          ;; alien values) both messy to do by hand and very important
 698          ;; for performance of later code which uses the return value.
 699          (declaim (ftype (function ,(lisp-arg-types)
 700                                    (values ,@(lisp-result-types) &optional))
 701                          ,lisp-name))
 702          (defun ,lisp-name ,(lisp-args)
 703            ,@(docs)
 704            (with-alien
 705             ((,lisp-name (function ,result-type ,@(arg-types))
 706                          :extern ,alien-name)
 707              ,@(alien-vars))
 708              #-nil
 709              (values (alien-funcall ,lisp-name ,@(alien-args))
 710                      ,@(results))
 711              #+nil
 712              (if (alien-values-type-p result-type)
 713                  ;; FIXME: RESULT-TYPE is a type specifier, so it
 714                  ;; cannot be of type ALIEN-VALUES-TYPE. Also note,
 715                  ;; that if RESULT-TYPE is VOID, then this code
 716                  ;; disagrees with the computation of the return type
 717                  ;; and with all usages of this macro. -- APD,
 718                  ;; 2002-03-02
 719                  (let ((temps (make-gensym-list
 720                                (length
 721                                 (alien-values-type-values result-type)))))
 722                    `(multiple-value-bind ,temps
 723                         (alien-funcall ,lisp-name ,@(alien-args))
 724                       (values ,@temps ,@(results))))
 725                  (values (alien-funcall ,lisp-name ,@(alien-args))
 726                          ,@(results)))))))))
 727 \f
 728 (defun alien-typep (object type)
 729   #!+sb-doc
 730   "Return T iff OBJECT is an alien of type TYPE."
 731   (let ((lisp-rep-type (compute-lisp-rep-type type)))
 732     (if lisp-rep-type
 733         (typep object lisp-rep-type)
 734         (and (alien-value-p object)
 735              (alien-subtype-p (alien-value-type object) type)))))
 736
 737 ;;;; ALIEN CALLBACKS
 738 ;;;;
 739 ;;;; See "Foreign Linkage / Callbacks" in the SBCL Internals manual.
 740
 741 (defvar *alien-callback-info* nil
 742   "Maps SAPs to corresponding CALLBACK-INFO structures: contains all the
 743 information we need to manipulate callbacks after their creation. Used for
 744 changing the lisp-side function they point to, invalidation, etc.")
 745
 746 (defstruct callback-info
 747   specifier
 748   function ; NULL if invalid
 749   wrapper
 750   index)
 751
 752 (defun callback-info-key (info)
 753   (cons (callback-info-specifier info) (callback-info-function info)))
 754
 755 (defun alien-callback-info (alien)
 756   (cdr (assoc (alien-sap alien) *alien-callback-info* :test #'sap=)))
 757
 758 (defvar *alien-callbacks* (make-hash-table :test #'equal)
 759   "Cache of existing callback SAPs, indexed with (SPECIFER . FUNCTION). Used for
 760 memoization: we don't create new callbacks if one pointing to the correct
 761 function with the same specifier already exists.")
 762
 763 (defvar *alien-callback-wrappers* (make-hash-table :test #'equal)
 764   "Cache of existing lisp weappers, indexed with SPECIFER. Used for memoization:
 765 we don't create new wrappers if one for the same specifier already exists.")
 766
 767 (defvar *alien-callback-trampolines* (make-array 32 :fill-pointer 0 :adjustable t)
 768   "Lisp trampoline store: assembler wrappers contain indexes to this, and
 769 ENTER-ALIEN-CALLBACK pulls the corresponsing trampoline out and calls it.")
 770
 771 (defun %alien-callback-sap (specifier result-type argument-types function wrapper)
 772   (let ((key (cons specifier function)))
 773     (or (gethash key *alien-callbacks*)
 774         (setf (gethash key *alien-callbacks*)
 775               (let* ((index (fill-pointer *alien-callback-trampolines*))
 776                      ;; Aside from the INDEX this is known at
 777                      ;; compile-time, which could be utilized by
 778                      ;; having the two-stage assembler tramp &
 779                      ;; wrapper mentioned in [1] above: only the
 780                      ;; per-function tramp would need assembler at
 781                      ;; runtime. Possibly we could even pregenerate
 782                      ;; the code and just patch the index in later.
 783                      (assembler-wrapper (alien-callback-assembler-wrapper
 784                                          index result-type argument-types)))
 785                 (vector-push-extend
 786                  (alien-callback-lisp-trampoline wrapper function)
 787                  *alien-callback-trampolines*)
 788                 ;; Assembler-wrapper is static, so sap-taking is safe.
 789                 (let ((sap (vector-sap assembler-wrapper)))
 790                   (push (cons sap (make-callback-info :specifier specifier
 791                                                       :function function
 792                                                       :wrapper wrapper
 793                                                       :index index))
 794                         *alien-callback-info*)
 795                   sap))))))
 796
 797 (defun alien-callback-lisp-trampoline (wrapper function)
 798   (declare (function wrapper) (optimize speed))
 799   (lambda (args-pointer result-pointer)
 800     (funcall wrapper args-pointer result-pointer function)))
 801
 802 (defun alien-callback-lisp-wrapper-lambda (specifier result-type argument-types env)
 803   (let* ((arguments (make-gensym-list (length argument-types)))
 804          (argument-names arguments)
 805          (argument-specs (cddr specifier)))
 806     `(lambda (args-pointer result-pointer function)
 807        ;; FIXME: the saps are not gc safe
 808        (let ((args-sap (int-sap
 809                         (sb!kernel:get-lisp-obj-address args-pointer)))
 810              (res-sap (int-sap
 811                        (sb!kernel:get-lisp-obj-address result-pointer))))
 812          (declare (ignorable args-sap res-sap))
 813          (with-alien
 814              ,(loop
 815                  with offset = 0
 816                  for spec in argument-specs
 817                  collect `(,(pop argument-names) ,spec
 818                             :local ,(alien-callback-accessor-form
 819                                      spec 'args-sap offset))
 820                  do (incf offset (alien-callback-argument-bytes spec env)))
 821            ,(flet ((store (spec)
 822                           (if spec
 823                               `(setf (deref (sap-alien res-sap (* ,spec)))
 824                                      (funcall function ,@arguments))
 825                               `(funcall function ,@arguments))))
 826                   (cond ((alien-void-type-p result-type)
 827                          (store nil))
 828                         ((alien-integer-type-p result-type)
 829                          (if (alien-integer-type-signed result-type)
 830                              (store `(signed
 831                                       ,(alien-type-word-aligned-bits result-type)))
 832                              (store
 833                               `(unsigned
 834                                 ,(alien-type-word-aligned-bits result-type)))))
 835                         (t
 836                          (store (unparse-alien-type result-type)))))))
 837        (values))))
 838
 839 (defun invalid-alien-callback (&rest arguments)
 840   (declare (ignore arguments))
 841   (error "Invalid alien callback called."))
 842
 843
 844 (defun parse-callback-specification (result-type lambda-list)
 845   (values
 846    `(function ,result-type ,@(mapcar #'second lambda-list))
 847    (mapcar #'first lambda-list)))
 848
 849
 850 (defun parse-alien-ftype (specifier env)
 851   (destructuring-bind (function result-type &rest argument-types)
 852       specifier
 853     (aver (eq 'function function))
 854     (values (let ((*values-type-okay* t))
 855               (parse-alien-type result-type env))
 856             (mapcar (lambda (spec)
 857                       (parse-alien-type spec env))
 858                     argument-types))))
 859
 860 (defun alien-void-type-p (type)
 861   (and (alien-values-type-p type) (not (alien-values-type-values type))))
 862
 863 (defun alien-type-word-aligned-bits (type)
 864   (align-offset (alien-type-bits type) sb!vm:n-word-bits))
 865
 866 (defun alien-callback-argument-bytes (spec env)
 867   (let ((type (parse-alien-type spec env)))
 868     (if (or (alien-integer-type-p type)
 869             (alien-float-type-p type)
 870             (alien-pointer-type-p type)
 871             (alien-system-area-pointer-type-p type))
 872         (ceiling (alien-type-word-aligned-bits type) sb!vm:n-byte-bits)
 873         (error "Unsupported callback argument type: ~A" type))))
 874
 875 (defun enter-alien-callback (index return arguments)
 876   (funcall (aref *alien-callback-trampolines* index)
 877            return
 878            arguments))
 879
 880 ;;; To ensure that callback wrapper functions continue working even
 881 ;;; if #'ENTER-ALIEN-CALLBACK moves in memory, access to it is indirected
 882 ;;; through the *ENTER-ALIEN-CALLBACK* static symbol. -- JES, 2006-01-01
 883 (defvar *enter-alien-callback* #'enter-alien-callback)
 884
 885 ;;;; interface (not public, yet) for alien callbacks
 886
 887 (defmacro alien-callback (specifier function &environment env)
 888   "Returns an alien-value with of alien ftype SPECIFIER, that can be passed to
 889 an alien function as a pointer to the FUNCTION. If a callback for the given
 890 SPECIFIER and FUNCTION already exists, it is returned instead of consing a new
 891 one."
 892   ;; Pull out as much work as is convenient to macro-expansion time, specifically
 893   ;; everything that can be done given just the SPECIFIER and ENV.
 894   (multiple-value-bind (result-type argument-types) (parse-alien-ftype specifier env)
 895     `(%sap-alien
 896       (%alien-callback-sap ',specifier ',result-type ',argument-types
 897                            ,function
 898                            (or (gethash ',specifier *alien-callback-wrappers*)
 899                                (setf (gethash ',specifier *alien-callback-wrappers*)
 900                                      (compile nil
 901                                               ',(alien-callback-lisp-wrapper-lambda
 902                                                  specifier result-type argument-types env)))))
 903       ',(parse-alien-type specifier env))))
 904
 905 (defun alien-callback-p (alien)
 906   "Returns true if the alien is associated with a lisp-side callback,
 907 and a secondary return value of true if the callback is still valid."
 908   (let ((info (alien-callback-info alien)))
 909     (when info
 910       (values t (and (callback-info-function info) t)))))
 911
 912 (defun alien-callback-function (alien)
 913   "Returns the lisp function designator associated with the callback."
 914   (let ((info (alien-callback-info alien)))
 915     (when info
 916       (callback-info-function info))))
 917
 918 (defun (setf alien-callback-function) (function alien)
 919   "Changes the lisp function designated by the callback."
 920   (let ((info (alien-callback-info alien)))
 921     (unless info
 922       (error "Not an alien callback: ~S" alien))
 923     ;; sap cache
 924     (let ((key (callback-info-key info)))
 925       (remhash key *alien-callbacks*)
 926       (setf (gethash key *alien-callbacks*) (alien-sap alien)))
 927     ;; trampoline
 928     (setf (aref *alien-callback-trampolines* (callback-info-index info))
 929           (alien-callback-lisp-trampoline (callback-info-wrapper info) function))
 930     ;; metadata
 931     (setf (callback-info-function info) function)
 932     function))
 933
 934 (defun invalidate-alien-callback (alien)
 935   "Invalidates the callback designated by the alien, if any, allowing the
 936 associated lisp function to be GC'd, and causing further calls to the same
 937 callback signal an error."
 938   (let ((info (alien-callback-info alien)))
 939     (when (and info (callback-info-function info))
 940       ;; sap cache
 941       (remhash (callback-info-key info) *alien-callbacks*)
 942       ;; trampoline
 943       (setf (aref *alien-callback-trampolines* (callback-info-index info))
 944             #'invalid-alien-callback)
 945       ;; metadata
 946       (setf (callback-info-function info) nil)
 947       t)))
 948
 949 ;;; FIXME: This call assembles a new callback for every closure,
 950 ;;; which sucks hugely. ...not that I can think of an obvious
 951 ;;; solution. Possibly maybe we could write a generalized closure
 952 ;;; callback analogous to closure_tramp, and share the actual wrapper?
 953 ;;;
 954 ;;; For lambdas that result in simple-funs we get the callback from
 955 ;;; the cache on subsequent calls.
 956 (defmacro alien-lambda (result-type typed-lambda-list &body forms)
 957   (multiple-value-bind (specifier lambda-list)
 958       (parse-callback-specification result-type typed-lambda-list)
 959     `(alien-callback ,specifier (lambda ,lambda-list ,@forms))))
 960
 961 ;;; FIXME: Should subsequent (SETF FDEFINITION) affect the callback or not?
 962 ;;; What about subsequent DEFINE-ALIEN-CALLBACKs? My guess is that changing
 963 ;;; the FDEFINITION should invalidate the callback, and redefining the
 964 ;;; callback should change existing callbacks to point to the new defintion.
 965 (defmacro define-alien-callback (name result-type typed-lambda-list &body forms)
 966   "Defines #'NAME as a function with the given body and lambda-list, and NAME as
 967 the alien callback for that function with the given alien type."
 968   (declare (symbol name))
 969   (multiple-value-bind (specifier lambda-list)
 970       (parse-callback-specification result-type typed-lambda-list)
 971     `(progn
 972        (defun ,name ,lambda-list ,@forms)
 973        (defparameter ,name (alien-callback ,specifier #',name)))))