1 ;;;; stuff related to the toplevel read-eval-print loop, plus some
2 ;;;; other miscellaneous functions that we don't have any better place
5 ;;;; This software is part of the SBCL system. See the README file for
8 ;;;; This software is derived from the CMU CL system, which was
9 ;;;; written at Carnegie Mellon University and released into the
10 ;;;; public domain. The software is in the public domain and is
11 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
12 ;;;; files for more information.
14 (in-package "SB!IMPL")
16 ;;;; magic specials initialized by GENESIS
18 ;;; FIXME: The DEFVAR here is redundant with the (DECLAIM (SPECIAL ..))
19 ;;; of all static symbols in early-impl.lisp.
21 (defvar sb!vm::*current-catch-block*)
22 (defvar sb!vm::*current-unwind-protect-block*)
23 (defvar *free-interrupt-context-index*))
25 ;;; specials initialized by !COLD-INIT
27 ;;; FIXME: These could be converted to DEFVARs.
28 (declaim (special #!+(or x86 x86-64) *pseudo-atomic-bits*
29 sb!unix::*interrupts-enabled*
30 sb!unix::*interrupt-pending*
31 *type-system-initialized*))
33 (defvar *cold-init-complete-p*)
35 ;;; counts of nested errors (with internal errors double-counted)
36 (defvar *maximum-error-depth*)
37 (defvar *current-error-depth*)
39 ;;;; default initfiles
41 (defun sysinit-pathname ()
42 (or (let ((sbcl-homedir (sbcl-homedir-pathname)))
44 (probe-file (merge-pathnames sbcl-homedir "sbclrc"))))
46 (merge-pathnames (sb!win32::get-folder-pathname
47 sb!win32::csidl_common_appdata)
52 (defun userinit-pathname ()
53 (merge-pathnames ".sbclrc" (user-homedir-pathname)))
55 (defvar *sysinit-pathname-function* #'sysinit-pathname
57 "Designator for a function of zero arguments called to obtain a pathname
58 designator for the default sysinit file, or NIL. If the function returns NIL,
59 no sysinit file is used unless one has been specified on the command-line.")
61 (defvar *userinit-pathname-function* #'userinit-pathname
63 "Designator for a function of zero arguments called to obtain a pathname
64 designator or a stream for the default userinit file, or NIL. If the function
65 returns NIL, no userinit file is used unless one has been specified on the
71 (defvar *step-form-stack* nil
73 "A place for single steppers to push information about
74 STEP-FORM-CONDITIONS avaiting the corresponding
75 STEP-VALUES-CONDITIONS. The system is guaranteed to empty the stack
76 when stepping terminates, so that it remains in sync, but doesn't
77 modify it in any other way: it is provided for implmentors of single
78 steppers to maintain contextual information.")
80 ;;;; miscellaneous utilities for working with with TOPLEVEL
82 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
83 ;;; by QUIT) is caught and any final processing and return codes are
84 ;;; handled appropriately.
85 (defmacro handling-end-of-the-world (&body body)
86 (with-unique-names (caught)
87 `(let ((,caught (catch '%end-of-the-world
88 (/show0 "inside CATCH '%END-OF-THE-WORLD")
90 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
91 (flush-standard-output-streams)
92 (sb!thread::terminate-session)
93 (/show0 "calling UNIX-EXIT")
94 (sb!unix:unix-exit ,caught))))
96 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
98 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
100 (defmacro infinite-error-protect (&rest forms)
101 `(unless (infinite-error-protector)
102 (/show0 "back from INFINITE-ERROR-PROTECTOR")
103 (let ((*current-error-depth* (1+ *current-error-depth*)))
104 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
105 ;; arbitrary truncation
106 #!+sb-show (sb!debug:backtrace 8)
109 ;;; a helper function for INFINITE-ERROR-PROTECT
110 (defun infinite-error-protector ()
111 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
112 (/hexstr *current-error-depth*)
113 (cond ((not *cold-init-complete-p*)
114 (%primitive print "Argh! error in cold init, halting")
115 (%primitive sb!c:halt))
116 ((or (not (boundp '*current-error-depth*))
117 (not (realp *current-error-depth*))
118 (not (boundp '*maximum-error-depth*))
119 (not (realp *maximum-error-depth*)))
120 (%primitive print "Argh! corrupted error depth, halting")
121 (%primitive sb!c:halt))
122 ((> *current-error-depth* *maximum-error-depth*)
123 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
124 (/hexstr *maximum-error-depth*)
125 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
126 (error-error "Help! "
127 *current-error-depth*
129 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
132 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
135 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
136 ;;; one point (shown below), and SBCL cross-compiled it without
137 ;;; warning about FORMS being undefined. Check whether that problem
138 ;;; (missing warning) is repeatable in the final system and if so, fix
141 (defun infinite-error-protector ()
142 `(cond ((not *cold-init-complete-p*)
143 (%primitive print "Argh! error in cold init, halting")
144 (%primitive sb!c:halt))
145 ((or (not (boundp '*current-error-depth*))
146 (not (realp *current-error-depth*))
147 (not (boundp '*maximum-error-depth*))
148 (not (realp *maximum-error-depth*)))
149 (%primitive print "Argh! corrupted error depth, halting")
150 (%primitive sb!c:halt))
151 ((> *current-error-depth* *maximum-error-depth*)
152 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
153 (error-error "Help! "
154 *current-error-depth*
156 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
160 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
164 ;;;; miscellaneous external functions
168 "This function causes execution to be suspended for N seconds. N may
169 be any non-negative, non-complex number."
170 (when (or (not (realp n))
172 (error 'simple-type-error
173 :format-control "invalid argument to SLEEP: ~S"
174 :format-arguments (list n)
176 :expected-type '(real 0)))
178 (multiple-value-bind (sec nsec)
181 (multiple-value-bind (sec frac)
183 (values sec (truncate frac 1e-9))))
184 (sb!unix:nanosleep sec nsec))
186 (sb!win32:millisleep (truncate (* n 1000)))
189 ;;;; SCRUB-CONTROL-STACK
191 (defconstant bytes-per-scrub-unit 2048)
193 ;;; Zero the unused portion of the control stack so that old objects
194 ;;; are not kept alive because of uninitialized stack variables.
196 ;;; "To summarize the problem, since not all allocated stack frame
197 ;;; slots are guaranteed to be written by the time you call an another
198 ;;; function or GC, there may be garbage pointers retained in your
199 ;;; dead stack locations. The stack scrubbing only affects the part
200 ;;; of the stack from the SP to the end of the allocated stack."
201 ;;; - ram, on cmucl-imp, Tue, 25 Sep 2001
203 ;;; So, as an (admittedly lame) workaround, from time to time we call
204 ;;; scrub-control-stack to zero out all the unused portion. This is
205 ;;; supposed to happen when the stack is mostly empty, so that we have
206 ;;; a chance of clearing more of it: callers are currently (2002.07.18)
209 (defun scrub-control-stack ()
210 (declare (optimize (speed 3) (safety 0))
211 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
213 #!-stack-grows-downward-not-upward
214 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
215 (initial-offset (logand csp (1- bytes-per-scrub-unit)))
217 (- (sap-int (sb!di::descriptor-sap sb!vm:*control-stack-end*))
218 sb!c:*backend-page-size*)))
220 ((scrub (ptr offset count)
221 (declare (type system-area-pointer ptr)
222 (type (unsigned-byte 16) offset)
223 (type (unsigned-byte 20) count)
224 (values (unsigned-byte 20)))
225 (cond ((>= (sap-int ptr) end-of-stack) 0)
226 ((= offset bytes-per-scrub-unit)
227 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
229 (setf (sap-ref-word ptr offset) 0)
230 (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
231 (look (ptr offset count)
232 (declare (type system-area-pointer ptr)
233 (type (unsigned-byte 16) offset)
234 (type (unsigned-byte 20) count)
235 (values (unsigned-byte 20)))
236 (cond ((>= (sap-int ptr) end-of-stack) 0)
237 ((= offset bytes-per-scrub-unit)
239 ((zerop (sap-ref-word ptr offset))
240 (look ptr (+ offset sb!vm:n-word-bytes) count))
242 (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
243 (declare (type sb!vm::word csp))
244 (scrub (int-sap (- csp initial-offset))
245 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
248 #!+stack-grows-downward-not-upward
249 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
250 (end-of-stack (+ (sap-int (sb!di::descriptor-sap sb!vm:*control-stack-start*))
251 sb!c:*backend-page-size*))
252 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
254 ((scrub (ptr offset count)
255 (declare (type system-area-pointer ptr)
256 (type (unsigned-byte 16) offset)
257 (type (unsigned-byte 20) count)
258 (values (unsigned-byte 20)))
259 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
260 (cond ((< (sap-int loc) end-of-stack) 0)
261 ((= offset bytes-per-scrub-unit)
262 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
264 (t ;; need to fix bug in %SET-STACK-REF
265 (setf (sap-ref-word loc 0) 0)
266 (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
267 (look (ptr offset count)
268 (declare (type system-area-pointer ptr)
269 (type (unsigned-byte 16) offset)
270 (type (unsigned-byte 20) count)
271 (values (unsigned-byte 20)))
272 (let ((loc (int-sap (- (sap-int ptr) offset))))
273 (cond ((< (sap-int loc) end-of-stack) 0)
274 ((= offset bytes-per-scrub-unit)
276 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
277 (look ptr (+ offset sb!vm:n-word-bytes) count))
279 (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
280 (declare (type sb!vm::word csp))
281 (scrub (int-sap (+ csp initial-offset))
282 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
285 ;;;; the default toplevel function
289 "a list of all the values returned by the most recent top level EVAL")
290 (defvar // nil #!+sb-doc "the previous value of /")
291 (defvar /// nil #!+sb-doc "the previous value of //")
292 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
293 (defvar ** nil #!+sb-doc "the previous value of *")
294 (defvar *** nil #!+sb-doc "the previous value of **")
295 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
296 (defvar ++ nil #!+sb-doc "the previous value of +")
297 (defvar +++ nil #!+sb-doc "the previous value of ++")
298 (defvar - nil #!+sb-doc "the form currently being evaluated")
300 (defun interactive-eval (form)
302 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
303 +++, ++, +, ///, //, /, and -."
306 (let ((results (multiple-value-list (eval form))))
317 ;; The bogon returned an unbound marker.
318 ;; FIXME: It would be safer to check every one of the values in RESULTS,
319 ;; instead of just the first one.
321 (cerror "Go on with * set to NIL."
322 "EVAL returned an unbound marker."))
325 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
326 ;;; output streams before proceeding.
327 (defun flush-standard-output-streams ()
328 (dolist (name '(*debug-io*
334 ;; FINISH-OUTPUT may block more easily than FORCE-OUTPUT
335 (force-output (symbol-value name)))
338 (defun process-init-file (specified-pathname default-function)
340 (let ((cookie (list)))
341 (flet ((process-stream (stream &optional pathname)
346 (error "Error during processing of ~
347 initialization file ~A:~%~% ~A"
348 (or pathname stream) e))))
349 (let ((form (read stream nil cookie)))
351 (return-from process-init-file nil)
354 :report "Ignore and continue processing.")))))
355 (if specified-pathname
356 (with-open-file (stream (parse-native-namestring specified-pathname)
357 :if-does-not-exist nil)
359 (process-stream stream (pathname stream))
360 (error "The specified init file ~S was not found."
361 specified-pathname)))
362 (let ((default (funcall default-function)))
364 (with-open-file (stream (pathname default) :if-does-not-exist nil)
366 (process-stream stream (pathname stream)))))))))
368 :report "Skip this initialization file.")))
370 (defun process-eval-options (eval-strings-or-forms)
371 (/show0 "handling --eval options")
372 (flet ((process-1 (string-or-form)
373 (etypecase string-or-form
375 (multiple-value-bind (expr pos) (read-from-string string-or-form)
376 (unless (eq string-or-form
377 (read-from-string string-or-form nil string-or-form
379 (error "More than one expression in ~S" string-or-form))
381 (flush-standard-output-streams)))
382 (cons (eval string-or-form) (flush-standard-output-streams)))))
384 (dolist (expr-as-string-or-form eval-strings-or-forms)
385 (/show0 "handling one --eval option")
389 (error "Error during processing of --eval ~
391 expr-as-string-or-form e))))
392 (process-1 expr-as-string-or-form))
394 :report "Ignore and continue with next --eval option.")))
396 :report "Skip rest of --eval options."))))
398 ;; Errors while processing the command line cause the system to QUIT,
399 ;; instead of trying to go into the Lisp debugger, because trying to
400 ;; go into the Lisp debugger would get into various annoying issues of
401 ;; where we should go after the user tries to return from the
403 (defun startup-error (control-string &rest args)
404 (format *error-output*
405 "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
408 (quit :unix-status 1))
410 ;;; the default system top level function
411 (defun toplevel-init ()
412 (/show0 "entering TOPLEVEL-INIT")
413 (let ( ;; value of --sysinit option
415 ;; t if --no-sysinit option given
417 ;; value of --userinit option
419 ;; t if --no-userinit option given
421 ;; values of --eval options, in reverse order; and also any
422 ;; other options (like --load) which're translated into --eval
424 ;; The values are stored as strings, so that they can be
425 ;; passed to READ only after their predecessors have been
426 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL
427 ;; form creates a package referred to in the next EVAL form,
428 ;; except for forms transformed from syntactically-sugary
429 ;; switches like --load and --disable-debugger.
431 ;; Has a --noprint option been seen?
433 ;; everything in *POSIX-ARGV* except for argv[0]=programname
434 (options (rest *posix-argv*)))
436 (declare (type list options))
438 (/show0 "done with outer LET in TOPLEVEL-INIT")
440 ;; FIXME: There are lots of ways for errors to happen around here
441 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
442 ;; READ an --eval string). Make sure that they're handled
445 ;; Process command line options.
446 (loop while options do
447 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
448 (let ((option (first options)))
449 (flet ((pop-option ()
453 "unexpected end of command line options"))))
454 (cond ((string= option "--sysinit")
457 (startup-error "multiple --sysinit options")
458 (setf sysinit (pop-option))))
459 ((string= option "--no-sysinit")
462 ((string= option "--userinit")
465 (startup-error "multiple --userinit options")
466 (setf userinit (pop-option))))
467 ((string= option "--no-userinit")
469 (setf no-userinit t))
470 ((string= option "--eval")
472 (push (pop-option) reversed-evals))
473 ((string= option "--load")
476 (list 'cl:load (native-pathname (pop-option)))
478 ((string= option "--noprint")
481 ((string= option "--disable-debugger")
483 (push (list 'sb!ext:disable-debugger) reversed-evals))
484 ((string= option "--end-toplevel-options")
488 ;; Anything we don't recognize as a toplevel
489 ;; option must be the start of user-level
490 ;; options.. except that if we encounter
491 ;; "--end-toplevel-options" after we gave up
492 ;; because we didn't recognize an option as a
493 ;; toplevel option, then the option we gave up on
494 ;; must have been an error. (E.g. in
495 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
496 ;; this test will let us detect that the string
497 ;; "--eval(b)" is an error.)
498 (if (find "--end-toplevel-options" options
500 (startup-error "bad toplevel option: ~S"
503 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
505 ;; Delete all the options that we processed, so that only
506 ;; user-level options are left visible to user code.
507 (setf (rest *posix-argv*) options)
509 ;; Handle initialization files.
510 (/show0 "handling initialization files in TOPLEVEL-INIT")
511 ;; This CATCH is needed for the debugger command TOPLEVEL to
513 (catch 'toplevel-catcher
514 ;; We wrap all the pre-REPL user/system customized startup
515 ;; code in a restart.
517 ;; (Why not wrap everything, even the stuff above, in this
518 ;; restart? Errors above here are basically command line
519 ;; or Unix environment errors, e.g. a missing file or a
520 ;; typo on the Unix command line, and you don't need to
521 ;; get into Lisp to debug them, you should just start over
522 ;; and do it right at the Unix level. Errors below here
523 ;; are generally errors in user Lisp code, and it might be
524 ;; helpful to let the user reach the REPL in order to help
525 ;; figure out what's going on.)
529 (process-init-file sysinit *sysinit-pathname-function*))
531 (process-init-file userinit *userinit-pathname-function*))
532 (process-eval-options (nreverse reversed-evals)))
534 :report "Skip to toplevel READ/EVAL/PRINT loop."
535 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
536 (values)) ; (no-op, just fall through)
538 :report "Quit SBCL (calling #'QUIT, killing the process)."
539 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
540 (quit :unix-status 1))))
542 ;; one more time for good measure, in case we fell out of the
543 ;; RESTART-CASE above before one of the flushes in the ordinary
544 ;; flow of control had a chance to operate
545 (flush-standard-output-streams)
547 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
548 (toplevel-repl noprint)
549 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
550 (critically-unreachable "after TOPLEVEL-REPL")))
552 ;;; hooks to support customized toplevels like ACL-style toplevel from
553 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
554 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
555 (defvar *repl-read-form-fun* #'repl-read-form-fun
557 "A function of two stream arguments IN and OUT for the toplevel REPL to
558 call: Return the next Lisp form to evaluate (possibly handling other magic --
559 like ACL-style keyword commands -- which precede the next Lisp form). The OUT
560 stream is there to support magic which requires issuing new prompts.")
561 (defvar *repl-prompt-fun* #'repl-prompt-fun
563 "A function of one argument STREAM for the toplevel REPL to call: Prompt
564 the user for input.")
565 (defvar *repl-fun-generator* (constantly #'repl-fun)
567 "A function of no arguments returning a function of one argument NOPRINT
568 that provides the REPL for the system. Assumes that *STANDARD-INPUT* and
569 *STANDARD-OUTPUT* are set up.")
571 ;;; read-eval-print loop for the default system toplevel
572 (defun toplevel-repl (noprint)
573 (/show0 "entering TOPLEVEL-REPL")
574 (let ((* nil) (** nil) (*** nil)
576 (+ nil) (++ nil) (+++ nil)
577 (/// nil) (// nil) (/ nil))
578 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
579 (let ((repl-fun (funcall *repl-fun-generator*)))
580 ;; Each REPL in a multithreaded world should have bindings of
581 ;; most CL specials (most critically *PACKAGE*).
582 (with-rebound-io-syntax
583 (handler-bind ((step-condition 'invoke-stepper))
584 (let ((*stepping* nil)
587 (/show0 "about to set up restarts in TOPLEVEL-REPL")
588 ;; CLHS recommends that there should always be an
589 ;; ABORT restart; we have this one here, and one per
592 (abort "~@<Exit debugger, returning to top level.~@:>")
593 (catch 'toplevel-catcher
594 #!-win32 (sb!unix::reset-signal-mask)
595 ;; In the event of a control-stack-exhausted-error, we
596 ;; should have unwound enough stack by the time we get
597 ;; here that this is now possible.
599 (sb!kernel::protect-control-stack-guard-page 1)
600 (funcall repl-fun noprint)
601 (critically-unreachable "after REPL"))))))))))
603 ;;; Our default REPL prompt is the minimal traditional one.
604 (defun repl-prompt-fun (stream)
606 (write-string "* " stream)) ; arbitrary but customary REPL prompt
608 ;;; Our default form reader does relatively little magic, but does
609 ;;; handle the Unix-style EOF-is-end-of-process convention.
610 (defun repl-read-form-fun (in out)
611 (declare (type stream in out) (ignore out))
612 (let* ((eof-marker (cons nil nil))
613 (form (read in nil eof-marker)))
614 (if (eq form eof-marker)
618 (defun repl-fun (noprint)
619 (/show0 "entering REPL")
623 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
624 (scrub-control-stack)
625 (sb!thread::get-foreground)
627 (flush-standard-output-streams)
628 (funcall *repl-prompt-fun* *standard-output*)
629 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
630 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
631 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
632 ;; odd. But maybe there *is* a valid reason in some
633 ;; circumstances? perhaps some deadlock issue when being driven
634 ;; by another process or something...)
635 (force-output *standard-output*))
636 (let* ((form (funcall *repl-read-form-fun*
639 (results (multiple-value-list (interactive-eval form))))
641 (dolist (result results)
644 ;; If we started stepping in the debugger we want to stop now.
648 ;;; a convenient way to get into the assembly-level debugger
650 (%primitive sb!c:halt))