src/code/load.lisp

   1 ;;;; parts of the loader which make sense in the cross-compilation
   2 ;;;; host (and which are useful in the host, because they're used by
   3 ;;;; GENESIS)
   4 ;;;;
   5 ;;;; based on the CMU CL load.lisp code, written by Skef Wholey and
   6 ;;;; Rob Maclachlan
   7
   8 ;;;; This software is part of the SBCL system. See the README file for
   9 ;;;; more information.
  10 ;;;;
  11 ;;;; This software is derived from the CMU CL system, which was
  12 ;;;; written at Carnegie Mellon University and released into the
  13 ;;;; public domain. The software is in the public domain and is
  14 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  15 ;;;; files for more information.
  16
  17 (in-package "SB!FASL")
  18 \f
  19 ;;;; There looks to be an exciting amount of state being modified
  20 ;;;; here: certainly enough that I (dan, 2003.1.22) don't want to mess
  21 ;;;; around deciding how to thread-safetify it.  So we use a Big Lock.
  22 ;;;; Because this code is mutually recursive with the compiler, we use
  23 ;;;; the **WORLD-LOCK**.
  24
  25 ;;;; miscellaneous load utilities
  26
  27 ;;; Output the current number of semicolons after a fresh-line.
  28 ;;; FIXME: non-mnemonic name
  29 (defun load-fresh-line ()
  30   (fresh-line)
  31   (let ((semicolons ";;;;;;;;;;;;;;;;"))
  32     (do ((count *load-depth* (- count (length semicolons))))
  33         ((< count (length semicolons))
  34          (write-string semicolons *standard-output* :end count))
  35       (declare (fixnum count))
  36       (write-string semicolons))
  37     (write-char #\space)))
  38
  39 ;;; If VERBOSE, output (to *STANDARD-OUTPUT*) a message about how
  40 ;;; we're loading from STREAM-WE-ARE-LOADING-FROM.
  41 (defun maybe-announce-load (stream-we-are-loading-from verbose)
  42   (when verbose
  43     (load-fresh-line)
  44     (let ((name #-sb-xc-host (file-name stream-we-are-loading-from)
  45                 #+sb-xc-host nil))
  46       (if name
  47           (format t "loading ~S~%" name)
  48           (format t "loading stuff from ~S~%" stream-we-are-loading-from)))))
  49 \f
  50 ;;;; utilities for reading from fasl files
  51
  52 #!-sb-fluid (declaim (inline read-byte))
  53
  54 ;;; This expands into code to read an N-byte unsigned integer using
  55 ;;; FAST-READ-BYTE.
  56 (defmacro fast-read-u-integer (n)
  57   (let (bytes)
  58     `(let ,(loop for i from 0 below n
  59                  collect (let ((name (gensym "B")))
  60                            (push name bytes)
  61                            `(,name ,(if (zerop i)
  62                                         `(fast-read-byte)
  63                                         `(ash (fast-read-byte) ,(* i 8))))))
  64        (logior ,@bytes))))
  65
  66 ;;; like FAST-READ-U-INTEGER, but the size may be determined at run time
  67 (defmacro fast-read-var-u-integer (n)
  68   (let ((n-pos (gensym))
  69         (n-res (gensym))
  70         (n-cnt (gensym)))
  71     `(do ((,n-pos 8 (+ ,n-pos 8))
  72           (,n-cnt (1- ,n) (1- ,n-cnt))
  73           (,n-res
  74            (fast-read-byte)
  75            (dpb (fast-read-byte) (byte 8 ,n-pos) ,n-res)))
  76          ((zerop ,n-cnt) ,n-res)
  77        (declare (type index ,n-pos ,n-cnt)))))
  78
  79 ;;; FIXME: why do all of these reading functions and macros declare
  80 ;;; (SPEED 0)?  was there some bug in the compiler which has since
  81 ;;; been fixed?  --njf, 2004-09-08
  82
  83 ;;; Read a signed integer.
  84 (defmacro fast-read-s-integer (n)
  85   (declare (optimize (speed 0)))
  86   (let ((n-last (gensym)))
  87     (do ((res `(let ((,n-last (fast-read-byte)))
  88                  (if (zerop (logand ,n-last #x80))
  89                      ,n-last
  90                      (logior ,n-last #x-100)))
  91               `(logior (fast-read-byte)
  92                        (ash (the (signed-byte ,(* cnt 8)) ,res) 8)))
  93          (cnt 1 (1+ cnt)))
  94         ((>= cnt n) res))))
  95
  96 ;;; Read an N-byte unsigned integer from the *FASL-INPUT-STREAM*.
  97 (defmacro read-arg (n)
  98   (declare (optimize (speed 0)))
  99   (if (= n 1)
 100       `(the (unsigned-byte 8) (read-byte *fasl-input-stream*))
 101       `(with-fast-read-byte ((unsigned-byte 8) *fasl-input-stream*)
 102          (fast-read-u-integer ,n))))
 103
 104 ;; FIXME: on x86-64, these functions exceed 600, 900, and 1200 bytes of code
 105 ;; respectively. Either don't inline them, or make a "really" fast inline case
 106 ;; that punts if inapplicable. e.g. if the fast-read-byte buffer will not be
 107 ;; refilled, then SAP-REF-WORD could work to read 8 bytes.
 108 ;; But this would only be feasible on machines that are little-endian
 109 ;; and that allow unaligned reads. (like x86)
 110 (declaim (inline read-byte-arg read-halfword-arg read-word-arg))
 111 (defun read-byte-arg ()
 112   (declare (optimize (speed 0)))
 113   (read-arg 1))
 114
 115 (defun read-halfword-arg ()
 116   (declare (optimize (speed 0)))
 117   (read-arg #.(/ sb!vm:n-word-bytes 2)))
 118
 119 (defun read-word-arg ()
 120   (declare (optimize (speed 0)))
 121   (read-arg #.sb!vm:n-word-bytes))
 122
 123 (defun read-unsigned-byte-32-arg ()
 124   (declare (optimize (speed 0)))
 125   (read-arg 4))
 126
 127 \f
 128 ;;;; the fop table
 129
 130 ;;; The table is implemented as a simple-vector indexed by the table
 131 ;;; offset. The offset is kept in at index 0 of the vector.
 132 ;;;
 133 ;;; FOPs use the table to save stuff, other FOPs refer to the table by
 134 ;;; direct indexes via REF-FOP-TABLE.
 135
 136 (defvar *fop-table*)
 137 (declaim (simple-vector *fop-table*))
 138
 139 (declaim (inline ref-fop-table))
 140 (defun ref-fop-table (index)
 141   (declare (type index index))
 142   (svref *fop-table* (the index (+ index 1))))
 143
 144 (defun get-fop-table-index ()
 145   (svref *fop-table* 0))
 146
 147 (defun reset-fop-table ()
 148   (setf (svref *fop-table* 0) 0))
 149
 150 (defun push-fop-table (thing) ; and return THING
 151   (let* ((table *fop-table*)
 152          (index (+ (the index (aref table 0)) 1)))
 153     (declare (fixnum index)
 154              (simple-vector table))
 155     (when (eql index (length table))
 156       (setf table (grow-fop-vector table index)
 157             *fop-table* table))
 158     (setf (aref table 0) index
 159           (aref table index) thing)))
 160
 161 ;;; These three routines are used for both the stack and the table.
 162 (defun make-fop-vector (size)
 163   (declare (type index size))
 164   (let ((vector (make-array size)))
 165     (setf (aref vector 0) 0)
 166     vector))
 167
 168 (defun grow-fop-vector (old-vector old-size)
 169   (declare (simple-vector old-vector)
 170            (type index old-size))
 171   (let* ((new-size (* old-size 2))
 172          (new-vector (make-array new-size)))
 173     (declare (fixnum new-size)
 174              (simple-vector new-vector old-vector))
 175     (replace new-vector old-vector)
 176     (nuke-fop-vector old-vector)
 177     new-vector))
 178
 179 (defun nuke-fop-vector (vector)
 180   (declare (simple-vector vector)
 181            #!-gencgc (ignore vector)
 182            (optimize speed))
 183   ;; Make sure we don't keep any garbage.
 184   #!+gencgc
 185   (fill vector 0))
 186
 187 \f
 188 ;;;; the fop stack
 189
 190 ;;; Much like the table, this is bound to a simple vector whose first
 191 ;;; element is the current index.
 192 (defvar *fop-stack*)
 193 (declaim (simple-vector *fop-stack*))
 194
 195 (declaim (inline fop-stack-empty-p))
 196 (defun fop-stack-empty-p ()
 197   (eql 0 (svref *fop-stack* 0)))
 198
 199 ;; Ensure that N arguments can be popped from the FOP stack.
 200 ;; Return the stack and the pointer to the first argument.
 201 ;; Update the new top-of-stack to reflect that all N have been popped.
 202 (defun fop-stack-pop-n (n)
 203   (declare (type index n))
 204   (let* ((stack *fop-stack*)
 205          (top (the index (svref stack 0)))
 206          (new-top (- top n)))
 207     (if (minusp new-top) ; 0 is ok at this point
 208         (error "FOP stack underflow")
 209         (progn (setf (svref stack 0) new-top)
 210                (values stack (1+ new-top))))))
 211
 212 (defun push-fop-stack (value)
 213   (let* ((stack *fop-stack*)
 214          (next (1+ (the index (svref stack 0)))))
 215     (declare (type index next))
 216     (when (eql (length stack) next)
 217       (setf stack (grow-fop-vector stack next)
 218             *fop-stack* stack))
 219     (setf (svref stack 0) next
 220           (svref stack next) value)))
 221
 222 \f
 223 ;;;; Conditions signalled on invalid fasls (wrong fasl version, etc),
 224 ;;;; so that user code (esp. ASDF) can reasonably handle attempts to
 225 ;;;; load such fasls by recompiling them, etc. For simplicity's sake
 226 ;;;; make only condition INVALID-FASL part of the public interface,
 227 ;;;; and keep the guts internal.
 228
 229 (define-condition invalid-fasl (error)
 230   ((stream :reader invalid-fasl-stream :initarg :stream)
 231    (expected :reader invalid-fasl-expected :initarg :expected))
 232   (:report
 233    (lambda (condition stream)
 234      (format stream "~S is an invalid fasl file."
 235              (invalid-fasl-stream condition)))))
 236
 237 (define-condition invalid-fasl-header (invalid-fasl)
 238   ((byte :reader invalid-fasl-byte :initarg :byte)
 239    (byte-nr :reader invalid-fasl-byte-nr :initarg :byte-nr))
 240   (:report
 241    (lambda (condition stream)
 242      (format stream "~@<~S contains an illegal byte in the FASL header at ~
 243                      position ~A: Expected ~A, got ~A.~:@>"
 244              (invalid-fasl-stream condition)
 245              (invalid-fasl-byte-nr condition)
 246              (invalid-fasl-expected condition)
 247              (invalid-fasl-byte condition)))))
 248
 249 (define-condition invalid-fasl-version (invalid-fasl)
 250   ((version :reader invalid-fasl-version :initarg :version))
 251   (:report
 252    (lambda (condition stream)
 253      (format stream "~@<~S is a fasl file compiled with SBCL ~W, and ~
 254                       can't be loaded into SBCL ~W.~:@>"
 255              (invalid-fasl-stream condition)
 256              (invalid-fasl-version condition)
 257              (invalid-fasl-expected condition)))))
 258
 259 (define-condition invalid-fasl-implementation (invalid-fasl)
 260   ((implementation :reader invalid-fasl-implementation
 261                    :initarg :implementation))
 262   (:report
 263    (lambda (condition stream)
 264      (format stream "~S was compiled for implementation ~A, but this is a ~A."
 265              (invalid-fasl-stream condition)
 266              (invalid-fasl-implementation condition)
 267              (invalid-fasl-expected condition)))))
 268
 269 (define-condition invalid-fasl-features (invalid-fasl)
 270   ((potential-features :reader invalid-fasl-potential-features
 271                        :initarg :potential-features)
 272    (features :reader invalid-fasl-features :initarg :features))
 273   (:report
 274    (lambda (condition stream)
 275      (format stream "~@<incompatible ~S in fasl file ~S: ~2I~_~
 276                      Of features affecting binary compatibility, ~4I~_~S~2I~_~
 277                      the fasl has ~4I~_~A,~2I~_~
 278                      while the runtime expects ~4I~_~A.~:>"
 279              '*features*
 280              (invalid-fasl-stream condition)
 281              (invalid-fasl-potential-features condition)
 282              (invalid-fasl-features condition)
 283              (invalid-fasl-expected condition)))))
 284
 285 ;;; Skips past the shebang line on stream, if any.
 286 (defun maybe-skip-shebang-line (stream)
 287   (let ((p (file-position stream)))
 288     (flet ((next () (read-byte stream nil)))
 289       (unwind-protect
 290            (when (and (eq (next) (char-code #\#))
 291                       (eq (next) (char-code #\!)))
 292              (setf p nil)
 293              (loop for x = (next)
 294                    until (or (not x) (eq x (char-code #\newline)))))
 295         (when p
 296           (file-position stream p))))
 297     t))
 298
 299 ;;; Returns T if the stream is a binary input stream with a FASL header.
 300 (defun fasl-header-p (stream &key errorp)
 301   (unless (and (member (stream-element-type stream) '(character base-char))
 302                ;; give up if it's not a file stream, or it's an
 303                ;; fd-stream but it's either not bivalent or not
 304                ;; seekable (doesn't really have a file)
 305                (or (not (typep stream 'file-stream))
 306                    (and (typep stream 'fd-stream)
 307                         (or (not (sb!impl::fd-stream-bivalent-p stream))
 308                             (not (sb!impl::fd-stream-file stream))))))
 309     (let ((p (file-position stream)))
 310       (unwind-protect
 311            (let* ((header *fasl-header-string-start-string*)
 312                   (buffer (make-array (length header) :element-type '(unsigned-byte 8)))
 313                   (n 0))
 314              (flet ((scan ()
 315                       (maybe-skip-shebang-line stream)
 316                       (setf n (read-sequence buffer stream))))
 317                (if errorp
 318                    (scan)
 319                    (or (ignore-errors (scan))
 320                        ;; no a binary input stream
 321                        (return-from fasl-header-p nil))))
 322              (if (mismatch buffer header
 323                            :test #'(lambda (code char) (= code (char-code char))))
 324                  ;; Immediate EOF is valid -- we want to match what
 325                  ;; CHECK-FASL-HEADER does...
 326                  (or (zerop n)
 327                      (when errorp
 328                        (error 'fasl-header-missing
 329                               :stream stream
 330                               :fhsss buffer
 331                               :expected header)))
 332                  t))
 333         (file-position stream p)))))
 334
 335
 336 ;;;; LOAD-AS-FASL
 337 ;;;;
 338 ;;;; Note: LOAD-AS-FASL is used not only by LOAD, but also (with
 339 ;;;; suitable modification of the fop table) in GENESIS. Therefore,
 340 ;;;; it's needed not only in the target Lisp, but also in the
 341 ;;;; cross-compilation host.
 342
 343 ;;; a helper function for LOAD-FASL-GROUP
 344 ;;;
 345 ;;; Return true if we successfully read a FASL header from the stream, or NIL
 346 ;;; if EOF was hit before anything except the optional shebang line was read.
 347 ;;; Signal an error if we encounter garbage.
 348 (defun check-fasl-header (stream)
 349   (maybe-skip-shebang-line stream)
 350   (let ((byte (read-byte stream nil)))
 351     (when byte
 352       ;; Read and validate constant string prefix in fasl header.
 353       (let* ((fhsss *fasl-header-string-start-string*)
 354              (fhsss-length (length fhsss)))
 355         (unless (= byte (char-code (schar fhsss 0)))
 356           (error 'invalid-fasl-header
 357                  :stream stream
 358                  :byte-nr 0
 359                  :byte byte
 360                  :expected (char-code (schar fhsss 0))))
 361         (do ((byte (read-byte stream) (read-byte stream))
 362              (count 1 (1+ count)))
 363             ((= byte +fasl-header-string-stop-char-code+)
 364              t)
 365           (declare (fixnum byte count))
 366           (when (and (< count fhsss-length)
 367                      (not (eql byte (char-code (schar fhsss count)))))
 368             (error 'invalid-fasl-header
 369                    :stream stream
 370                    :byte-nr count
 371                    :byte byte
 372                    :expected (char-code (schar fhsss count))))))
 373       ;; Read and validate version-specific compatibility stuff.
 374       (flet ((string-from-stream ()
 375                (let* ((length (read-unsigned-byte-32-arg))
 376                       (result (make-string length)))
 377                  (read-string-as-bytes stream result)
 378                  result)))
 379         ;; Read and validate implementation and version.
 380         (let ((implementation (keywordicate (string-from-stream)))
 381               (expected-implementation +backend-fasl-file-implementation+))
 382           (unless (string= expected-implementation implementation)
 383             (error 'invalid-fasl-implementation
 384                    :stream stream
 385                    :implementation implementation
 386                    :expected expected-implementation)))
 387         (let* ((fasl-version (read-word-arg))
 388                (sbcl-version (if (<= fasl-version 76)
 389                                  "1.0.11.18"
 390                                  (string-from-stream)))
 391                (expected-version (sb!xc:lisp-implementation-version)))
 392           (unless (string= expected-version sbcl-version)
 393             (restart-case
 394                 (error 'invalid-fasl-version
 395                        :stream stream
 396                        :version sbcl-version
 397                        :expected expected-version)
 398               (continue () :report "Load the fasl file anyway"))))
 399         ;; Read and validate *FEATURES* which affect binary compatibility.
 400         (let ((faff-in-this-file (string-from-stream)))
 401           (unless (string= faff-in-this-file *features-affecting-fasl-format*)
 402             (error 'invalid-fasl-features
 403                    :stream stream
 404                    :potential-features *features-potentially-affecting-fasl-format*
 405                    :expected *features-affecting-fasl-format*
 406                    :features faff-in-this-file)))
 407         ;; success
 408         t))))
 409
 410 ;; Setting this variable gives you a trace of fops as they are loaded and
 411 ;; executed.
 412 #!+sb-show
 413 (defvar *show-fops-p* nil)
 414
 415 ;;;
 416 ;;; a helper function for LOAD-AS-FASL
 417 ;;;
 418 ;;; Return true if we successfully load a group from the stream, or
 419 ;;; NIL if EOF was encountered while trying to read from the stream.
 420 ;;; Dispatch to the right function for each fop.
 421 (defconstant +2-operand-fops+ #xE0) ; start of the range
 422 (defun load-fasl-group (stream print)
 423   ;;
 424   ;; PRINT causes most tlf-equivalent forms to print their primary value.
 425   ;; This differs from loading of Lisp source, which prints all values of
 426   ;; only truly-toplevel forms.  This is permissible per CLHS -
 427   ;;  "If print is true, load incrementally prints information to standard
 428   ;;   output showing the progress of the loading process. [...]
 429   ;;   For a compiled file, what is printed might not reflect precisely the
 430   ;;   contents of the source file, but some information is generally printed."
 431   ;;
 432   (declare (ignorable print))
 433   (unless (check-fasl-header stream)
 434     (return-from load-fasl-group))
 435   (catch 'fasl-group-end
 436     (reset-fop-table)
 437     (let ((*skip-until* nil))
 438       (declare (special *skip-until*))
 439       (loop
 440        (let ((byte (the (unsigned-byte 8) (read-byte stream)))
 441              (trace (or #!+sb-show *show-fops-p*)))
 442          ;; Do some debugging output.
 443          (when trace
 444            (format *trace-output* "~&~6x : [~D,~D] ~2,'0x(~A)"
 445                    (1- (file-position stream))
 446                    (svref *fop-stack* 0) ; stack pointer
 447                    (svref *fop-table* 0) ; table pointer
 448                    byte (aref *fop-names* byte)))
 449          ;; Actually execute the fop.
 450          (let ((result
 451                 (let ((function (svref *fop-funs* byte)))
 452                   (cond ((not (functionp function))
 453                          (error "corrupt fasl file: FOP code #x~x" byte))
 454                         ((zerop (sbit (car *fop-signatures*) (ash byte -2)))
 455                          (funcall function)) ; takes no arguments
 456                         (t
 457                          (let (arg1 arg2) ; See !%DEFINE-FOP for encoding
 458                            (with-fast-read-byte ((unsigned-byte 8) stream)
 459                              (setq arg1 (fast-read-var-u-integer
 460                                          (ash 1 (logand byte 3))))
 461                              (when (>= byte +2-operand-fops+)
 462                                (setq arg2 (fast-read-var-u-integer
 463                                            (ash 1 (ldb (byte 2 2) byte))))))
 464                            (when trace
 465                              (format *trace-output* "{~D~@[,~D~]}" arg1 arg2))
 466                            (if arg2
 467                                (funcall function arg1 arg2)
 468                                (funcall function arg1))))))))
 469            (when (plusp (sbit (cdr *fop-signatures*) byte))
 470              (push-fop-stack result))
 471            (when trace
 472              (let* ((stack *fop-stack*)
 473                     (ptr (svref stack 0)))
 474                (format *trace-output* " -- ~[<empty>,~D~:;[~:*~D,~D] ~S~]"
 475                        ptr (svref *fop-table* 0)
 476                        (unless (eql ptr 0) (aref stack ptr)))
 477                (terpri *trace-output*)))
 478            #-sb-xc-host
 479            (macrolet ((terminator-opcode ()
 480                         (or (get 'fop-funcall-for-effect 'opcode)
 481                             (error "Missing FOP definition?"))))
 482              (when (and print
 483                         (eq byte (terminator-opcode))
 484                         (fop-stack-empty-p)) ; (presumed) end of TLF
 485                (load-fresh-line)
 486                (prin1 result)))))))))
 487
 488 (defun load-as-fasl (stream verbose print)
 489   (when (zerop (file-length stream))
 490     (error "attempt to load an empty FASL file:~%  ~S" (namestring stream)))
 491   (maybe-announce-load stream verbose)
 492   (let* ((*fasl-input-stream* stream)
 493          (*fop-table* (make-fop-vector 1000))
 494          (*fop-stack* (make-fop-vector 100)))
 495     (unwind-protect
 496          (loop while (load-fasl-group stream print))
 497       ;; Nuke the table and stack to avoid keeping garbage on
 498       ;; conservatively collected platforms.
 499       (nuke-fop-vector *fop-table*)
 500       (nuke-fop-vector *fop-stack*)))
 501   t)
 502
 503 (declaim (notinline read-byte)) ; Why is it even *declaimed* inline above?
 504 \f
 505 ;;;; stuff for debugging/tuning by collecting statistics on FOPs (?)
 506
 507 #|
 508 (defvar *fop-counts* (make-array 256 :initial-element 0))
 509 (defvar *fop-times* (make-array 256 :initial-element 0))
 510 (defvar *print-fops* nil)
 511
 512 (defun clear-counts ()
 513   (fill (the simple-vector *fop-counts*) 0)
 514   (fill (the simple-vector *fop-times*) 0)
 515   t)
 516
 517 (defun analyze-counts ()
 518   (let ((counts ())
 519         (total-count 0)
 520         (times ())
 521         (total-time 0))
 522     (macrolet ((breakdown (lvar tvar vec)
 523                  `(progn
 524                    (dotimes (i 255)
 525                      (declare (fixnum i))
 526                      (let ((n (svref ,vec i)))
 527                        (push (cons (svref *fop-names* i) n) ,lvar)
 528                        (incf ,tvar n)))
 529                    (setq ,lvar (subseq (sort ,lvar (lambda (x y)
 530                                                      (> (cdr x) (cdr y))))
 531                                        0 10)))))
 532
 533       (breakdown counts total-count *fop-counts*)
 534       (breakdown times total-time *fop-times*)
 535       (format t "Total fop count is ~D~%" total-count)
 536       (dolist (c counts)
 537         (format t "~30S: ~4D~%" (car c) (cdr c)))
 538       (format t "~%Total fop time is ~D~%" (/ (float total-time) 60.0))
 539       (dolist (m times)
 540         (format t "~30S: ~6,2F~%" (car m) (/ (float (cdr m)) 60.0))))))
 541 |#
 542