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     (setf (info :variable :alien-info lisp-name)
  70           (make-heap-alien-info :type type
  71                                 :sap-form `(foreign-symbol-sap ',alien-name t)))))
  72
  73 (defmacro extern-alien (name type &environment env)
  74   #!+sb-doc
  75   "Access the alien variable named NAME, assuming it is of type TYPE. This
  76    is SETFable."
  77   (let* ((alien-name (etypecase name
  78                        (symbol (guess-alien-name-from-lisp-name name))
  79                        (string name)))
  80          (alien-type (parse-alien-type type env))
  81          (datap (not (alien-fun-type-p alien-type))))
  82     `(%heap-alien ',(make-heap-alien-info
  83                      :type alien-type
  84                      :sap-form `(foreign-symbol-sap ',alien-name ,datap)))))
  85
  86 (defmacro with-alien (bindings &body body &environment env)
  87   #!+sb-doc
  88   "Establish some local alien variables. Each BINDING is of the form:
  89      VAR TYPE [ ALLOCATION ] [ INITIAL-VALUE | EXTERNAL-NAME ]
  90    ALLOCATION should be one of:
  91      :LOCAL (the default)
  92        The alien is allocated on the stack, and has dynamic extent.
  93      :EXTERN
  94        No alien is allocated, but VAR is established as a local name for
  95        the external alien given by EXTERNAL-NAME."
  96   ;; FIXME:
  97   ;;      :STATIC
  98   ;;        The alien is allocated on the heap, and has infinite extent. The alien
  99   ;;        is allocated at load time, so the same piece of memory is used each time
 100   ;;        this form executes.
 101   (/show "entering WITH-ALIEN" bindings)
 102   (let (bind-alien-stack)
 103     (with-auxiliary-alien-types env
 104       (dolist (binding (reverse bindings))
 105         (/show binding)
 106         (destructuring-bind
 107               (symbol type &optional (opt1 nil opt1p) (opt2 nil opt2p))
 108             binding
 109           (/show symbol type opt1 opt2)
 110           (let* ((alien-type (parse-alien-type type env))
 111                  (datap (not (alien-fun-type-p alien-type))))
 112             (/show alien-type)
 113             (multiple-value-bind (allocation initial-value)
 114                 (if opt2p
 115                     (values opt1 opt2)
 116                     (case opt1
 117                       (:extern
 118                        (values opt1 (guess-alien-name-from-lisp-name symbol)))
 119                       (:static
 120                        (values opt1 nil))
 121                       (t
 122                        (values :local opt1))))
 123               (/show allocation initial-value)
 124               (setf body
 125                     (ecase allocation
 126                       #+nil
 127                       (:static
 128                        (let ((sap
 129                               (make-symbol (concatenate 'string "SAP-FOR-"
 130                                                         (symbol-name symbol)))))
 131                          `((let ((,sap (load-time-value (%make-alien ...))))
 132                              (declare (type system-area-pointer ,sap))
 133                              (symbol-macrolet
 134                                  ((,symbol (sap-alien ,sap ,type)))
 135                                ,@(when initial-value
 136                                        `((setq ,symbol ,initial-value)))
 137                                ,@body)))))
 138                       (:extern
 139                        (/show0 ":EXTERN case")
 140                        (let ((info (make-heap-alien-info
 141                                     :type alien-type
 142                                     :sap-form `(foreign-symbol-sap ',initial-value
 143                                                                    ,datap))))
 144                          `((symbol-macrolet
 145                                ((,symbol (%heap-alien ',info)))
 146                              ,@body))))
 147                       (:local
 148                        (/show0 ":LOCAL case")
 149                        (let* ((var (gensym))
 150                               (initval (if initial-value (gensym)))
 151                               (info (make-local-alien-info :type alien-type))
 152                               (inner-body
 153                                `((note-local-alien-type ',info ,var)
 154                                  (symbol-macrolet ((,symbol (local-alien ',info ,var)))
 155                                    ,@(when initial-value
 156                                            `((setq ,symbol ,initval)))
 157                                    ,@body)))
 158                               (body-forms
 159                                (if initial-value
 160                                    `((let ((,initval ,initial-value))
 161                                        ,@inner-body))
 162                                    inner-body)))
 163                          (/show var initval info)
 164                          #!+(or x86 x86-64)
 165                          (progn
 166                            (setf bind-alien-stack t)
 167                            `((let ((,var (make-local-alien ',info)))
 168                                ,@body-forms)))
 169                          ;; FIXME: This version is less efficient then it needs to be, since
 170                          ;; it could just save and restore the number-stack pointer once,
 171                          ;; instead of doing multiple decrements if there are multiple bindings.
 172                          #!-(or x86 x86-64)
 173                          `((let (,var)
 174                              (unwind-protect
 175                                   (progn
 176                                     (setf ,var (make-local-alien ',info))
 177                                     (let ((,var ,var))
 178                                       ,body-form))
 179                                (dispose-local-alien ',info ,var))))))))))))
 180       (/show "revised" body)
 181       (verify-local-auxiliaries-okay)
 182       (/show0 "back from VERIFY-LOCAL-AUXILIARIES-OK, returning")
 183       `(symbol-macrolet ((&auxiliary-type-definitions&
 184                           ,(append *new-auxiliary-types*
 185                                    (auxiliary-type-definitions env))))
 186          ,@(if bind-alien-stack
 187                `((let ((sb!vm::*alien-stack* sb!vm::*alien-stack*))
 188                    ,@body))
 189                body)))))
 190 \f
 191 ;;;; runtime C values that don't correspond directly to Lisp types
 192
 193 ;;; Note: The DEFSTRUCT for ALIEN-VALUE lives in a separate file
 194 ;;; 'cause it has to be real early in the cold-load order.
 195 #!-sb-fluid (declaim (freeze-type alien-value))
 196 (def!method print-object ((value alien-value) stream)
 197   (print-unreadable-object (value stream)
 198     (format stream
 199             "~S ~S #X~8,'0X ~S ~S"
 200             'alien-value
 201             :sap (sap-int (alien-value-sap value))
 202             :type (unparse-alien-type (alien-value-type value)))))
 203
 204 #!-sb-fluid (declaim (inline null-alien))
 205 (defun null-alien (x)
 206   #!+sb-doc
 207   "Return true if X (which must be an ALIEN pointer) is null, false otherwise."
 208   (zerop (sap-int (alien-sap x))))
 209
 210 (defmacro sap-alien (sap type &environment env)
 211   #!+sb-doc
 212   "Convert the system area pointer SAP to an ALIEN of the specified TYPE (not
 213    evaluated.) TYPE must be pointer-like."
 214   (let ((alien-type (parse-alien-type type env)))
 215     (if (eq (compute-alien-rep-type alien-type) 'system-area-pointer)
 216         `(%sap-alien ,sap ',alien-type)
 217         (error "cannot make an alien of type ~S out of a SAP" type))))
 218
 219 (defun %sap-alien (sap type)
 220   (declare (type system-area-pointer sap)
 221            (type alien-type type))
 222   (make-alien-value :sap sap :type type))
 223
 224 (defun alien-sap (alien)
 225   #!+sb-doc
 226   "Return a System-Area-Pointer pointing to Alien's data."
 227   (declare (type alien-value alien))
 228   (alien-value-sap alien))
 229 \f
 230 ;;;; allocation/deallocation of heap aliens
 231
 232 (defmacro make-alien (type &optional size &environment env)
 233   #!+sb-doc
 234   "Allocate an alien of type TYPE and return an alien pointer to it. If SIZE
 235 is supplied, how it is interpreted depends on TYPE. If TYPE is an array type,
 236 SIZE is used as the first dimension for the allocated array. If TYPE is not an
 237 array, then SIZE is the number of elements to allocate. The memory is
 238 allocated using ``malloc'', so it can be passed to foreign functions which use
 239 ``free''."
 240   (let ((alien-type (if (alien-type-p type)
 241                         type
 242                         (parse-alien-type type env))))
 243     (multiple-value-bind (size-expr element-type)
 244         (if (alien-array-type-p alien-type)
 245             (let ((dims (alien-array-type-dimensions alien-type)))
 246               (cond
 247                 (size
 248                  (unless dims
 249                    (error
 250                     "cannot override the size of zero-dimensional arrays"))
 251                  (when (constantp size)
 252                    (setf alien-type (copy-alien-array-type alien-type))
 253                    (setf (alien-array-type-dimensions alien-type)
 254                          (cons (constant-form-value size) (cdr dims)))))
 255                 (dims
 256                  (setf size (car dims)))
 257                 (t
 258                  (setf size 1)))
 259               (values `(* ,size ,@(cdr dims))
 260                       (alien-array-type-element-type alien-type)))
 261             (values (or size 1) alien-type))
 262       (let ((bits (alien-type-bits element-type))
 263             (alignment (alien-type-alignment element-type)))
 264         (unless bits
 265           (error "The size of ~S is unknown."
 266                  (unparse-alien-type element-type)))
 267         (unless alignment
 268           (error "The alignment of ~S is unknown."
 269                  (unparse-alien-type element-type)))
 270         ;; This is the one place where the %SAP-ALIEN note is quite
 271         ;; undesirable, in most uses of MAKE-ALIEN the %SAP-ALIEN
 272         ;; cannot be optimized away.
 273         `(locally (declare (muffle-conditions compiler-note))
 274            (%sap-alien (%make-alien (* ,(align-offset bits alignment)
 275                                        ,size-expr))
 276                        ',(make-alien-pointer-type :to alien-type)))))))
 277
 278 ;;; Allocate a block of memory at least BITS bits long and return a
 279 ;;; system area pointer to it.
 280 #!-sb-fluid (declaim (inline %make-alien))
 281 (defun %make-alien (bits)
 282   (declare (type index bits))
 283   (alien-funcall (extern-alien "malloc"
 284                                (function system-area-pointer unsigned))
 285                  (ash (the index (+ bits 7)) -3)))
 286
 287 #!-sb-fluid (declaim (inline free-alien))
 288 (defun free-alien (alien)
 289   #!+sb-doc
 290   "Dispose of the storage pointed to by ALIEN. ALIEN must have been allocated
 291    by MAKE-ALIEN or malloc(3)."
 292   (alien-funcall (extern-alien "free" (function (values) system-area-pointer))
 293                  (alien-sap alien))
 294   nil)
 295 \f
 296 ;;;; the SLOT operator
 297
 298 ;;; Find the field named SLOT, or die trying.
 299 (defun slot-or-lose (type slot)
 300   (declare (type alien-record-type type)
 301            (type symbol slot))
 302   (or (find slot (alien-record-type-fields type)
 303             :key #'alien-record-field-name)
 304       (error "There is no slot named ~S in ~S." slot type)))
 305
 306 ;;; Extract the value from the named slot from the record ALIEN. If
 307 ;;; ALIEN is actually a pointer, then DEREF it first.
 308 (defun slot (alien slot)
 309   #!+sb-doc
 310   "Extract SLOT from the Alien STRUCT or UNION ALIEN. May be set with SETF."
 311   (declare (type alien-value alien)
 312            (type symbol slot)
 313            (optimize (inhibit-warnings 3)))
 314   (let ((type (alien-value-type alien)))
 315     (etypecase type
 316       (alien-pointer-type
 317        (slot (deref alien) slot))
 318       (alien-record-type
 319        (let ((field (slot-or-lose type slot)))
 320          (extract-alien-value (alien-value-sap alien)
 321                               (alien-record-field-offset field)
 322                               (alien-record-field-type field)))))))
 323
 324 ;;; Deposit the value in the specified slot of the record ALIEN. If
 325 ;;; the ALIEN is really a pointer, DEREF it first. The compiler uses
 326 ;;; this when it can't figure out anything better.
 327 (defun %set-slot (alien slot value)
 328   (declare (type alien-value alien)
 329            (type symbol slot)
 330            (optimize (inhibit-warnings 3)))
 331   (let ((type (alien-value-type alien)))
 332     (etypecase type
 333       (alien-pointer-type
 334        (%set-slot (deref alien) slot value))
 335       (alien-record-type
 336        (let ((field (slot-or-lose type slot)))
 337          (deposit-alien-value (alien-value-sap alien)
 338                               (alien-record-field-offset field)
 339                               (alien-record-field-type field)
 340                               value))))))
 341
 342 ;;; Compute the address of the specified slot and return a pointer to it.
 343 (defun %slot-addr (alien slot)
 344   (declare (type alien-value alien)
 345            (type symbol slot)
 346            (optimize (inhibit-warnings 3)))
 347   (let ((type (alien-value-type alien)))
 348     (etypecase type
 349       (alien-pointer-type
 350        (%slot-addr (deref alien) slot))
 351       (alien-record-type
 352        (let* ((field (slot-or-lose type slot))
 353               (offset (alien-record-field-offset field))
 354               (field-type (alien-record-field-type field)))
 355          (%sap-alien (sap+ (alien-sap alien) (/ offset sb!vm:n-byte-bits))
 356                      (make-alien-pointer-type :to field-type)))))))
 357 \f
 358 ;;;; the DEREF operator
 359
 360 ;;; This function does most of the work of the different DEREF
 361 ;;; methods. It returns two values: the type and the offset (in bits)
 362 ;;; of the referred-to alien.
 363 (defun deref-guts (alien indices)
 364   (declare (type alien-value alien)
 365            (type list indices)
 366            (values alien-type integer))
 367   (let ((type (alien-value-type alien)))
 368     (etypecase type
 369       (alien-pointer-type
 370        (when (cdr indices)
 371          (error "too many indices when DEREF'ing ~S: ~W"
 372                 type
 373                 (length indices)))
 374        (let ((element-type (alien-pointer-type-to type)))
 375          (values element-type
 376                  (if indices
 377                      (* (align-offset (alien-type-bits element-type)
 378                                       (alien-type-alignment element-type))
 379                         (car indices))
 380                      0))))
 381       (alien-array-type
 382        (unless (= (length indices) (length (alien-array-type-dimensions type)))
 383          (error "incorrect number of indices when DEREF'ing ~S: ~W"
 384                 type (length indices)))
 385        (labels ((frob (dims indices offset)
 386                   (if (null dims)
 387                       offset
 388                       (frob (cdr dims) (cdr indices)
 389                         (+ (if (zerop offset)
 390                                0
 391                                (* offset (car dims)))
 392                            (car indices))))))
 393          (let ((element-type (alien-array-type-element-type type)))
 394            (values element-type
 395                    (* (align-offset (alien-type-bits element-type)
 396                                     (alien-type-alignment element-type))
 397                       (frob (alien-array-type-dimensions type)
 398                         indices 0)))))))))
 399
 400 ;;; Dereference the alien and return the results.
 401 (defun deref (alien &rest indices)
 402   #!+sb-doc
 403   "De-reference an Alien pointer or array. If an array, the indices are used
 404    as the indices of the array element to access. If a pointer, one index can
 405    optionally be specified, giving the equivalent of C pointer arithmetic."
 406   (declare (type alien-value alien)
 407            (type list indices)
 408            (optimize (inhibit-warnings 3)))
 409   (multiple-value-bind (target-type offset) (deref-guts alien indices)
 410     (extract-alien-value (alien-value-sap alien)
 411                          offset
 412                          target-type)))
 413
 414 (defun %set-deref (alien value &rest indices)
 415   (declare (type alien-value alien)
 416            (type list indices)
 417            (optimize (inhibit-warnings 3)))
 418   (multiple-value-bind (target-type offset) (deref-guts alien indices)
 419     (deposit-alien-value (alien-value-sap alien)
 420                          offset
 421                          target-type
 422                          value)))
 423
 424 (defun %deref-addr (alien &rest indices)
 425   (declare (type alien-value alien)
 426            (type list indices)
 427            (optimize (inhibit-warnings 3)))
 428   (multiple-value-bind (target-type offset) (deref-guts alien indices)
 429     (%sap-alien (sap+ (alien-value-sap alien) (/ offset sb!vm:n-byte-bits))
 430                 (make-alien-pointer-type :to target-type))))
 431 \f
 432 ;;;; accessing heap alien variables
 433
 434 (defun %heap-alien (info)
 435   (declare (type heap-alien-info info)
 436            (optimize (inhibit-warnings 3)))
 437   (extract-alien-value (eval (heap-alien-info-sap-form info))
 438                        0
 439                        (heap-alien-info-type info)))
 440
 441 (defun %set-heap-alien (info value)
 442   (declare (type heap-alien-info info)
 443            (optimize (inhibit-warnings 3)))
 444   (deposit-alien-value (eval (heap-alien-info-sap-form info))
 445                        0
 446                        (heap-alien-info-type info)
 447                        value))
 448
 449 (defun %heap-alien-addr (info)
 450   (declare (type heap-alien-info info)
 451            (optimize (inhibit-warnings 3)))
 452   (%sap-alien (eval (heap-alien-info-sap-form info))
 453               (make-alien-pointer-type :to (heap-alien-info-type info))))
 454 \f
 455 ;;;; accessing local aliens
 456
 457 (defun make-local-alien (info)
 458   (let* ((alien (eval `(make-alien ,(local-alien-info-type info))))
 459          (alien-sap (alien-sap alien)))
 460     (finalize
 461      alien
 462      (lambda ()
 463        (alien-funcall
 464         (extern-alien "free" (function (values) system-area-pointer))
 465         alien-sap))
 466      :dont-save t)
 467     alien))
 468
 469 (defun note-local-alien-type (info alien)
 470   (declare (ignore info alien))
 471   nil)
 472
 473 (defun local-alien (info alien)
 474   (declare (ignore info))
 475   (deref alien))
 476
 477 (defun %set-local-alien (info alien value)
 478   (declare (ignore info))
 479   (setf (deref alien) value))
 480
 481 (define-setf-expander local-alien (&whole whole info alien)
 482   (let ((value (gensym))
 483         (info-var (gensym))
 484         (alloc-tmp (gensym))
 485         (info (if (and (consp info)
 486                        (eq (car info) 'quote))
 487                   (second info)
 488                   (error "Something is wrong; local-alien-info not found: ~S"
 489                          whole))))
 490     (values nil
 491             nil
 492             (list value)
 493             `(if (%local-alien-forced-to-memory-p ',info)
 494                  (%set-local-alien ',info ,alien ,value)
 495                    (let* ((,info-var ',(local-alien-info-type info))
 496                           (,alloc-tmp (deport-alloc ,value ,info-var)))
 497                      (maybe-with-pinned-objects (,alloc-tmp) (,(local-alien-info-type info))
 498                        (setf ,alien (deport ,alloc-tmp ,info-var)))))
 499             whole)))
 500
 501 (defun %local-alien-forced-to-memory-p (info)
 502   (local-alien-info-force-to-memory-p info))
 503
 504 (defun %local-alien-addr (info alien)
 505   (declare (type local-alien-info info))
 506   (unless (local-alien-info-force-to-memory-p info)
 507     (error "~S isn't forced to memory. Something went wrong." alien))
 508   alien)
 509
 510 (defun dispose-local-alien (info alien)
 511   (declare (ignore info))
 512   (cancel-finalization alien)
 513   (free-alien alien))
 514 \f
 515 ;;;; the CAST macro
 516
 517 (defmacro cast (alien type &environment env)
 518   #!+sb-doc
 519   "Convert ALIEN to an Alien of the specified TYPE (not evaluated.)  Both types
 520    must be Alien array, pointer or function types."
 521   `(%cast ,alien ',(parse-alien-type type env)))
 522
 523 (defun %cast (alien target-type)
 524   (declare (type alien-value alien)
 525            (type alien-type target-type)
 526            (optimize (safety 2))
 527            (optimize (inhibit-warnings 3)))
 528   (if (or (alien-pointer-type-p target-type)
 529           (alien-array-type-p target-type)
 530           (alien-fun-type-p target-type))
 531       (let ((alien-type (alien-value-type alien)))
 532         (if (or (alien-pointer-type-p alien-type)
 533                 (alien-array-type-p alien-type)
 534                 (alien-fun-type-p alien-type))
 535             (naturalize (alien-value-sap alien) target-type)
 536             (error "~S cannot be casted." alien)))
 537       (error "cannot cast to alien type ~S" (unparse-alien-type target-type))))
 538 \f
 539 ;;;; the ALIEN-SIZE macro
 540
 541 (defmacro alien-size (type &optional (units :bits) &environment env)
 542   #!+sb-doc
 543   "Return the size of the alien type TYPE. UNITS specifies the units to
 544    use and can be either :BITS, :BYTES, or :WORDS."
 545   (let* ((alien-type (parse-alien-type type env))
 546          (bits (alien-type-bits alien-type)))
 547     (if bits
 548         (values (ceiling bits
 549                          (ecase units
 550                            (:bits 1)
 551                            (:bytes sb!vm:n-byte-bits)
 552                            (:words sb!vm:n-word-bits))))
 553         (error "unknown size for alien type ~S"
 554                (unparse-alien-type alien-type)))))
 555 \f
 556 ;;;; NATURALIZE, DEPORT, EXTRACT-ALIEN-VALUE, DEPOSIT-ALIEN-VALUE
 557
 558 (defun coerce-to-interpreted-function (lambda-form)
 559   (let (#!+sb-eval
 560         (*evaluator-mode* :interpret))
 561     (coerce lambda-form 'function)))
 562
 563 (defun naturalize (alien type)
 564   (declare (type alien-type type))
 565   (funcall (coerce-to-interpreted-function (compute-naturalize-lambda type))
 566            alien type))
 567
 568 (defun deport (value type)
 569   (declare (type alien-type type))
 570   (funcall (coerce-to-interpreted-function (compute-deport-lambda type))
 571            value type))
 572
 573 (defun deport-alloc (value type)
 574   (declare (type alien-type type))
 575   (funcall (coerce-to-interpreted-function (compute-deport-alloc-lambda type))
 576            value type))
 577
 578 (defun extract-alien-value (sap offset type)
 579   (declare (type system-area-pointer sap)
 580            (type unsigned-byte offset)
 581            (type alien-type type))
 582   (funcall (coerce-to-interpreted-function (compute-extract-lambda type))
 583            sap offset type))
 584
 585 (defun deposit-alien-value (sap offset type value)
 586   (declare (type system-area-pointer sap)
 587            (type unsigned-byte offset)
 588            (type alien-type type))
 589   (funcall (coerce-to-interpreted-function (compute-deposit-lambda type))
 590            sap offset type value))
 591 \f
 592 ;;;; ALIEN-FUNCALL, DEFINE-ALIEN-ROUTINE
 593
 594 (defun alien-funcall (alien &rest args)
 595   #!+sb-doc
 596   "Call the foreign function ALIEN with the specified arguments. ALIEN's
 597    type specifies the argument and result types."
 598   (declare (type alien-value alien))
 599   (let ((type (alien-value-type alien)))
 600     (typecase type
 601       (alien-pointer-type
 602        (apply #'alien-funcall (deref alien) args))
 603       (alien-fun-type
 604        (unless (= (length (alien-fun-type-arg-types type))
 605                   (length args))
 606          (error "wrong number of arguments for ~S~%expected ~W, got ~W"
 607                 type
 608                 (length (alien-fun-type-arg-types type))
 609                 (length args)))
 610        (let ((stub (alien-fun-type-stub type)))
 611          (unless stub
 612            (setf stub
 613                  (let ((fun (gensym))
 614                        (parms (make-gensym-list (length args))))
 615                    (compile nil
 616                             `(lambda (,fun ,@parms)
 617                                (declare (optimize (sb!c::insert-step-conditions 0)))
 618                                (declare (type (alien ,type) ,fun))
 619                                (alien-funcall ,fun ,@parms)))))
 620            (setf (alien-fun-type-stub type) stub))
 621          (apply stub alien args)))
 622       (t
 623        (error "~S is not an alien function." alien)))))
 624
 625 (defmacro define-alien-routine (name result-type
 626                                      &rest args
 627                                      &environment lexenv)
 628   #!+sb-doc
 629   "DEFINE-ALIEN-ROUTINE Name Result-Type {(Arg-Name Arg-Type [Style])}*
 630
 631   Define a foreign interface function for the routine with the specified NAME.
 632   Also automatically DECLAIM the FTYPE of the defined function.
 633
 634   NAME may be either a string, a symbol, or a list of the form (string symbol).
 635
 636   RETURN-TYPE is the alien type for the function return value. VOID may be
 637   used to specify a function with no result.
 638
 639   The remaining forms specify individual arguments that are passed to the
 640   routine. ARG-NAME is a symbol that names the argument, primarily for
 641   documentation. ARG-TYPE is the C type of the argument. STYLE specifies the
 642   way that the argument is passed.
 643
 644   :IN
 645         An :IN argument is simply passed by value. The value to be passed is
 646         obtained from argument(s) to the interface function. No values are
 647         returned for :In arguments. This is the default mode.
 648
 649   :OUT
 650         The specified argument type must be a pointer to a fixed sized object.
 651         A pointer to a preallocated object is passed to the routine, and the
 652         the object is accessed on return, with the value being returned from
 653         the interface function. :OUT and :IN-OUT cannot be used with pointers
 654         to arrays, records or functions.
 655
 656   :COPY
 657         This is similar to :IN, except that the argument values are stored
 658         on the stack, and a pointer to the object is passed instead of
 659         the value itself.
 660
 661   :IN-OUT
 662         This is a combination of :OUT and :COPY. A pointer to the argument is
 663         passed, with the object being initialized from the supplied argument
 664         and the return value being determined by accessing the object on
 665         return."
 666   (multiple-value-bind (lisp-name alien-name)
 667       (pick-lisp-and-alien-names name)
 668     (collect ((docs) (lisp-args) (lisp-arg-types)
 669               (lisp-result-types
 670                (cond ((eql result-type 'void)
 671                       ;; What values does a function return, if it
 672                       ;; returns no values? Exactly one - NIL. -- APD,
 673                       ;; 2003-03-02
 674                       (list 'null))
 675                      (t
 676                       ;; FIXME: Check for VALUES.
 677                       (list `(alien ,result-type)))))
 678               (arg-types) (alien-vars)
 679               (alien-args) (results))
 680       (dolist (arg args)
 681         (if (stringp arg)
 682             (docs arg)
 683             (destructuring-bind (name type &optional (style :in)) arg
 684               (unless (member style '(:in :copy :out :in-out))
 685                 (error "bogus argument style ~S in ~S" style arg))
 686               (when (and (member style '(:out :in-out))
 687                          (typep (parse-alien-type type lexenv)
 688                                 'alien-pointer-type))
 689                 (error "can't use :OUT or :IN-OUT on pointer-like type:~%  ~S"
 690                        type))
 691               (let (arg-type)
 692                 (cond ((eq style :in)
 693                        (setq arg-type type)
 694                        (alien-args name))
 695                       (t
 696                        (setq arg-type `(* ,type))
 697                        (if (eq style :out)
 698                            (alien-vars `(,name ,type))
 699                            (alien-vars `(,name ,type ,name)))
 700                        (alien-args `(addr ,name))))
 701                 (arg-types arg-type)
 702                 (unless (eq style :out)
 703                   (lisp-args name)
 704                   (lisp-arg-types t
 705                                   ;; FIXME: It should be something
 706                                   ;; like `(ALIEN ,ARG-TYPE), except
 707                                   ;; for we also accept SAPs where
 708                                   ;; pointers are required.
 709                                   )))
 710               (when (or (eq style :out) (eq style :in-out))
 711                 (results name)
 712                 (lisp-result-types `(alien ,type))))))
 713       `(progn
 714          ;; The theory behind this automatic DECLAIM is that (1) if
 715          ;; you're calling C, static typing is what you're doing
 716          ;; anyway, and (2) such a declamation can be (especially for
 717          ;; alien values) both messy to do by hand and very important
 718          ;; for performance of later code which uses the return value.
 719          (declaim (ftype (function ,(lisp-arg-types)
 720                                    (values ,@(lisp-result-types) &optional))
 721                          ,lisp-name))
 722          (defun ,lisp-name ,(lisp-args)
 723            ,@(docs)
 724            (with-alien
 725             ((,lisp-name (function ,result-type ,@(arg-types))
 726                          :extern ,alien-name)
 727              ,@(alien-vars))
 728              #-nil
 729              (values (alien-funcall ,lisp-name ,@(alien-args))
 730                      ,@(results))
 731              #+nil
 732              (if (alien-values-type-p result-type)
 733                  ;; FIXME: RESULT-TYPE is a type specifier, so it
 734                  ;; cannot be of type ALIEN-VALUES-TYPE. Also note,
 735                  ;; that if RESULT-TYPE is VOID, then this code
 736                  ;; disagrees with the computation of the return type
 737                  ;; and with all usages of this macro. -- APD,
 738                  ;; 2002-03-02
 739                  (let ((temps (make-gensym-list
 740                                (length
 741                                 (alien-values-type-values result-type)))))
 742                    `(multiple-value-bind ,temps
 743                         (alien-funcall ,lisp-name ,@(alien-args))
 744                       (values ,@temps ,@(results))))
 745                  (values (alien-funcall ,lisp-name ,@(alien-args))
 746                          ,@(results)))))))))
 747 \f
 748 (defun alien-typep (object type)
 749   #!+sb-doc
 750   "Return T iff OBJECT is an alien of type TYPE."
 751   (let ((lisp-rep-type (compute-lisp-rep-type type)))
 752     (if lisp-rep-type
 753         (typep object lisp-rep-type)
 754         (and (alien-value-p object)
 755              (alien-subtype-p (alien-value-type object) type)))))
 756
 757 ;;;; ALIEN CALLBACKS
 758 ;;;;
 759 ;;;; See "Foreign Linkage / Callbacks" in the SBCL Internals manual.
 760
 761 (defvar *alien-callback-info* nil
 762   "Maps SAPs to corresponding CALLBACK-INFO structures: contains all the
 763 information we need to manipulate callbacks after their creation. Used for
 764 changing the lisp-side function they point to, invalidation, etc.")
 765
 766 (defstruct callback-info
 767   specifier
 768   function ; NULL if invalid
 769   wrapper
 770   index)
 771
 772 (defun callback-info-key (info)
 773   (cons (callback-info-specifier info) (callback-info-function info)))
 774
 775 (defun alien-callback-info (alien)
 776   (cdr (assoc (alien-sap alien) *alien-callback-info* :test #'sap=)))
 777
 778 (defvar *alien-callbacks* (make-hash-table :test #'equal)
 779   "Cache of existing callback SAPs, indexed with (SPECIFER . FUNCTION). Used for
 780 memoization: we don't create new callbacks if one pointing to the correct
 781 function with the same specifier already exists.")
 782
 783 (defvar *alien-callback-wrappers* (make-hash-table :test #'equal)
 784   "Cache of existing lisp weappers, indexed with SPECIFER. Used for memoization:
 785 we don't create new wrappers if one for the same specifier already exists.")
 786
 787 (defvar *alien-callback-trampolines* (make-array 32 :fill-pointer 0 :adjustable t)
 788   "Lisp trampoline store: assembler wrappers contain indexes to this, and
 789 ENTER-ALIEN-CALLBACK pulls the corresponsing trampoline out and calls it.")
 790
 791 (defun %alien-callback-sap (specifier result-type argument-types function wrapper)
 792   (let ((key (cons specifier function)))
 793     (or (gethash key *alien-callbacks*)
 794         (setf (gethash key *alien-callbacks*)
 795               (let* ((index (fill-pointer *alien-callback-trampolines*))
 796                      ;; Aside from the INDEX this is known at
 797                      ;; compile-time, which could be utilized by
 798                      ;; having the two-stage assembler tramp &
 799                      ;; wrapper mentioned in [1] above: only the
 800                      ;; per-function tramp would need assembler at
 801                      ;; runtime. Possibly we could even pregenerate
 802                      ;; the code and just patch the index in later.
 803                      (assembler-wrapper (alien-callback-assembler-wrapper
 804                                          index result-type argument-types)))
 805                 (vector-push-extend
 806                  (alien-callback-lisp-trampoline wrapper function)
 807                  *alien-callback-trampolines*)
 808                 ;; Assembler-wrapper is static, so sap-taking is safe.
 809                 (let ((sap (vector-sap assembler-wrapper)))
 810                   (push (cons sap (make-callback-info :specifier specifier
 811                                                       :function function
 812                                                       :wrapper wrapper
 813                                                       :index index))
 814                         *alien-callback-info*)
 815                   sap))))))
 816
 817 (defun alien-callback-lisp-trampoline (wrapper function)
 818   (declare (function wrapper) (optimize speed))
 819   (lambda (args-pointer result-pointer)
 820     (funcall wrapper args-pointer result-pointer function)))
 821
 822 (defun alien-callback-lisp-wrapper-lambda (specifier result-type argument-types env)
 823   (let* ((arguments (make-gensym-list (length argument-types)))
 824          (argument-names arguments)
 825          (argument-specs (cddr specifier)))
 826     `(lambda (args-pointer result-pointer function)
 827        ;; FIXME: the saps are not gc safe
 828        (let ((args-sap (int-sap
 829                         (sb!kernel:get-lisp-obj-address args-pointer)))
 830              (res-sap (int-sap
 831                        (sb!kernel:get-lisp-obj-address result-pointer))))
 832          (declare (ignorable args-sap res-sap))
 833          (with-alien
 834              ,(loop
 835                  with offset = 0
 836                  for spec in argument-specs
 837                  collect `(,(pop argument-names) ,spec
 838                             :local ,(alien-callback-accessor-form
 839                                      spec 'args-sap offset))
 840                  do (incf offset (alien-callback-argument-bytes spec env)))
 841            ,(flet ((store (spec)
 842                           (if spec
 843                               `(setf (deref (sap-alien res-sap (* ,spec)))
 844                                      (funcall function ,@arguments))
 845                               `(funcall function ,@arguments))))
 846                   (cond ((alien-void-type-p result-type)
 847                          (store nil))
 848                         ((alien-integer-type-p result-type)
 849                          (if (alien-integer-type-signed result-type)
 850                              (store `(signed
 851                                       ,(alien-type-word-aligned-bits result-type)))
 852                              (store
 853                               `(unsigned
 854                                 ,(alien-type-word-aligned-bits result-type)))))
 855                         (t
 856                          (store (unparse-alien-type result-type)))))))
 857        (values))))
 858
 859 (defun invalid-alien-callback (&rest arguments)
 860   (declare (ignore arguments))
 861   (error "Invalid alien callback called."))
 862
 863
 864 (defun parse-callback-specification (result-type lambda-list)
 865   (values
 866    `(function ,result-type ,@(mapcar #'second lambda-list))
 867    (mapcar #'first lambda-list)))
 868
 869
 870 (defun parse-alien-ftype (specifier env)
 871   (destructuring-bind (function result-type &rest argument-types)
 872       specifier
 873     (aver (eq 'function function))
 874     (values (let ((*values-type-okay* t))
 875               (parse-alien-type result-type env))
 876             (mapcar (lambda (spec)
 877                       (parse-alien-type spec env))
 878                     argument-types))))
 879
 880 (defun alien-void-type-p (type)
 881   (and (alien-values-type-p type) (not (alien-values-type-values type))))
 882
 883 (defun alien-type-word-aligned-bits (type)
 884   (align-offset (alien-type-bits type) sb!vm:n-word-bits))
 885
 886 (defun alien-callback-argument-bytes (spec env)
 887   (let ((type (parse-alien-type spec env)))
 888     (if (or (alien-integer-type-p type)
 889             (alien-float-type-p type)
 890             (alien-pointer-type-p type)
 891             (alien-system-area-pointer-type-p type))
 892         (ceiling (alien-type-word-aligned-bits type) sb!vm:n-byte-bits)
 893         (error "Unsupported callback argument type: ~A" type))))
 894
 895 (defun enter-alien-callback (index return arguments)
 896   (funcall (aref *alien-callback-trampolines* index)
 897            return
 898            arguments))
 899
 900 ;;; To ensure that callback wrapper functions continue working even
 901 ;;; if #'ENTER-ALIEN-CALLBACK moves in memory, access to it is indirected
 902 ;;; through the *ENTER-ALIEN-CALLBACK* static symbol. -- JES, 2006-01-01
 903 (defvar *enter-alien-callback* #'enter-alien-callback)
 904
 905 ;;;; interface (not public, yet) for alien callbacks
 906
 907 (defmacro alien-callback (specifier function &environment env)
 908   "Returns an alien-value with of alien ftype SPECIFIER, that can be passed to
 909 an alien function as a pointer to the FUNCTION. If a callback for the given
 910 SPECIFIER and FUNCTION already exists, it is returned instead of consing a new
 911 one."
 912   ;; Pull out as much work as is convenient to macro-expansion time, specifically
 913   ;; everything that can be done given just the SPECIFIER and ENV.
 914   (multiple-value-bind (result-type argument-types) (parse-alien-ftype specifier env)
 915     `(%sap-alien
 916       (%alien-callback-sap ',specifier ',result-type ',argument-types
 917                            ,function
 918                            (or (gethash ',specifier *alien-callback-wrappers*)
 919                                (setf (gethash ',specifier *alien-callback-wrappers*)
 920                                      (compile nil
 921                                               ',(alien-callback-lisp-wrapper-lambda
 922                                                  specifier result-type argument-types env)))))
 923       ',(parse-alien-type specifier env))))
 924
 925 (defun alien-callback-p (alien)
 926   "Returns true if the alien is associated with a lisp-side callback,
 927 and a secondary return value of true if the callback is still valid."
 928   (let ((info (alien-callback-info alien)))
 929     (when info
 930       (values t (and (callback-info-function info) t)))))
 931
 932 (defun alien-callback-function (alien)
 933   "Returns the lisp function designator associated with the callback."
 934   (let ((info (alien-callback-info alien)))
 935     (when info
 936       (callback-info-function info))))
 937
 938 (defun (setf alien-callback-function) (function alien)
 939   "Changes the lisp function designated by the callback."
 940   (let ((info (alien-callback-info alien)))
 941     (unless info
 942       (error "Not an alien callback: ~S" alien))
 943     ;; sap cache
 944     (let ((key (callback-info-key info)))
 945       (remhash key *alien-callbacks*)
 946       (setf (gethash key *alien-callbacks*) (alien-sap alien)))
 947     ;; trampoline
 948     (setf (aref *alien-callback-trampolines* (callback-info-index info))
 949           (alien-callback-lisp-trampoline (callback-info-wrapper info) function))
 950     ;; metadata
 951     (setf (callback-info-function info) function)
 952     function))
 953
 954 (defun invalidate-alien-callback (alien)
 955   "Invalidates the callback designated by the alien, if any, allowing the
 956 associated lisp function to be GC'd, and causing further calls to the same
 957 callback signal an error."
 958   (let ((info (alien-callback-info alien)))
 959     (when (and info (callback-info-function info))
 960       ;; sap cache
 961       (remhash (callback-info-key info) *alien-callbacks*)
 962       ;; trampoline
 963       (setf (aref *alien-callback-trampolines* (callback-info-index info))
 964             #'invalid-alien-callback)
 965       ;; metadata
 966       (setf (callback-info-function info) nil)
 967       t)))
 968
 969 ;;; FIXME: This call assembles a new callback for every closure,
 970 ;;; which sucks hugely. ...not that I can think of an obvious
 971 ;;; solution. Possibly maybe we could write a generalized closure
 972 ;;; callback analogous to closure_tramp, and share the actual wrapper?
 973 ;;;
 974 ;;; For lambdas that result in simple-funs we get the callback from
 975 ;;; the cache on subsequent calls.
 976 (defmacro alien-lambda (result-type typed-lambda-list &body forms)
 977   (multiple-value-bind (specifier lambda-list)
 978       (parse-callback-specification result-type typed-lambda-list)
 979     `(alien-callback ,specifier (lambda ,lambda-list ,@forms))))
 980
 981 ;;; FIXME: Should subsequent (SETF FDEFINITION) affect the callback or not?
 982 ;;; What about subsequent DEFINE-ALIEN-CALLBACKs? My guess is that changing
 983 ;;; the FDEFINITION should invalidate the callback, and redefining the
 984 ;;; callback should change existing callbacks to point to the new defintion.
 985 (defmacro define-alien-callback (name result-type typed-lambda-list &body forms)
 986   "Defines #'NAME as a function with the given body and lambda-list, and NAME as
 987 the alien callback for that function with the given alien type."
 988   (declare (symbol name))
 989   (multiple-value-bind (specifier lambda-list)
 990       (parse-callback-specification result-type typed-lambda-list)
 991     `(progn
 992        (defun ,name ,lambda-list ,@forms)
 993        (defparameter ,name (alien-callback ,specifier #',name)))))