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-atomic*
29 #!+(or x86 x86-64) *pseudo-atomic-interrupted*
30 sb!unix::*interrupts-enabled*
31 sb!unix::*interrupt-pending*
32 *type-system-initialized*))
34 (defvar *cold-init-complete-p*)
36 ;;; counts of nested errors (with internal errors double-counted)
37 (defvar *maximum-error-depth*)
38 (defvar *current-error-depth*)
40 ;;;; default initfiles
42 (defun sysinit-pathname ()
43 (or (let ((sbcl-homedir (sbcl-homedir-pathname)))
45 (probe-file (merge-pathnames sbcl-homedir "sbclrc"))))
47 (merge-pathnames (sb!win32::get-folder-pathname
48 sb!win32::csidl_common_appdata)
53 (defun userinit-pathname ()
54 (merge-pathnames ".sbclrc" (user-homedir-pathname)))
56 (defvar *sysinit-pathname-function* #'sysinit-pathname
58 "Designator for a function of zero arguments called to obtain a pathname
59 designator for the default sysinit file, or NIL. If the function returns NIL,
60 no sysinit file is used unless one has been specified on the command-line.")
62 (defvar *userinit-pathname-function* #'userinit-pathname
64 "Designator for a function of zero arguments called to obtain a pathname
65 designator or a stream for the default userinit file, or NIL. If the function
66 returns NIL, no userinit file is used unless one has been specified on the
72 (defvar *step-form-stack* nil
74 "A place for single steppers to push information about
75 STEP-FORM-CONDITIONS avaiting the corresponding
76 STEP-VALUES-CONDITIONS. The system is guaranteed to empty the stack
77 when stepping terminates, so that it remains in sync, but doesn't
78 modify it in any other way: it is provided for implmentors of single
79 steppers to maintain contextual information.")
81 ;;;; miscellaneous utilities for working with with TOPLEVEL
83 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
84 ;;; by QUIT) is caught and any final processing and return codes are
85 ;;; handled appropriately.
86 (defmacro handling-end-of-the-world (&body body)
87 (with-unique-names (caught)
88 `(let ((,caught (catch '%end-of-the-world
89 (/show0 "inside CATCH '%END-OF-THE-WORLD")
91 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
92 (flush-standard-output-streams)
93 (sb!thread::terminate-session)
94 (/show0 "calling UNIX-EXIT")
95 (sb!unix:unix-exit ,caught))))
97 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
99 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
101 (defmacro infinite-error-protect (&rest forms)
102 `(unless (infinite-error-protector)
103 (/show0 "back from INFINITE-ERROR-PROTECTOR")
104 (let ((*current-error-depth* (1+ *current-error-depth*)))
105 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
106 ;; arbitrary truncation
107 #!+sb-show (sb!debug:backtrace 8)
110 ;;; a helper function for INFINITE-ERROR-PROTECT
111 (defun infinite-error-protector ()
112 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
113 (/hexstr *current-error-depth*)
114 (cond ((not *cold-init-complete-p*)
115 (%primitive print "Argh! error in cold init, halting")
116 (%primitive sb!c:halt))
117 ((or (not (boundp '*current-error-depth*))
118 (not (realp *current-error-depth*))
119 (not (boundp '*maximum-error-depth*))
120 (not (realp *maximum-error-depth*)))
121 (%primitive print "Argh! corrupted error depth, halting")
122 (%primitive sb!c:halt))
123 ((> *current-error-depth* *maximum-error-depth*)
124 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
125 (/hexstr *maximum-error-depth*)
126 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
127 (error-error "Help! "
128 *current-error-depth*
130 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
133 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
136 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
137 ;;; one point (shown below), and SBCL cross-compiled it without
138 ;;; warning about FORMS being undefined. Check whether that problem
139 ;;; (missing warning) is repeatable in the final system and if so, fix
142 (defun infinite-error-protector ()
143 `(cond ((not *cold-init-complete-p*)
144 (%primitive print "Argh! error in cold init, halting")
145 (%primitive sb!c:halt))
146 ((or (not (boundp '*current-error-depth*))
147 (not (realp *current-error-depth*))
148 (not (boundp '*maximum-error-depth*))
149 (not (realp *maximum-error-depth*)))
150 (%primitive print "Argh! corrupted error depth, halting")
151 (%primitive sb!c:halt))
152 ((> *current-error-depth* *maximum-error-depth*)
153 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
154 (error-error "Help! "
155 *current-error-depth*
157 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
161 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
165 ;;;; miscellaneous external functions
169 "This function causes execution to be suspended for N seconds. N may
170 be any non-negative, non-complex number."
171 (when (or (not (realp n))
173 (error 'simple-type-error
174 :format-control "invalid argument to SLEEP: ~S"
175 :format-arguments (list n)
177 :expected-type '(real 0)))
179 (multiple-value-bind (sec nsec)
182 (multiple-value-bind (sec frac)
184 (values sec (truncate frac 1e-9))))
185 (sb!unix:nanosleep sec nsec))
187 (sb!win32:millisleep (truncate (* n 1000)))
190 ;;;; SCRUB-CONTROL-STACK
192 (defconstant bytes-per-scrub-unit 2048)
194 ;;; Zero the unused portion of the control stack so that old objects
195 ;;; are not kept alive because of uninitialized stack variables.
197 ;;; "To summarize the problem, since not all allocated stack frame
198 ;;; slots are guaranteed to be written by the time you call an another
199 ;;; function or GC, there may be garbage pointers retained in your
200 ;;; dead stack locations. The stack scrubbing only affects the part
201 ;;; of the stack from the SP to the end of the allocated stack."
202 ;;; - ram, on cmucl-imp, Tue, 25 Sep 2001
204 ;;; So, as an (admittedly lame) workaround, from time to time we call
205 ;;; scrub-control-stack to zero out all the unused portion. This is
206 ;;; supposed to happen when the stack is mostly empty, so that we have
207 ;;; a chance of clearing more of it: callers are currently (2002.07.18)
210 (defun scrub-control-stack ()
211 (declare (optimize (speed 3) (safety 0))
212 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
214 #!-stack-grows-downward-not-upward
215 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
216 (initial-offset (logand csp (1- bytes-per-scrub-unit)))
218 (- (sap-int (sb!di::descriptor-sap sb!vm:*control-stack-end*))
219 sb!c:*backend-page-size*)))
221 ((scrub (ptr offset count)
222 (declare (type system-area-pointer ptr)
223 (type (unsigned-byte 16) offset)
224 (type (unsigned-byte 20) count)
225 (values (unsigned-byte 20)))
226 (cond ((>= (sap-int ptr) end-of-stack) 0)
227 ((= offset bytes-per-scrub-unit)
228 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
230 (setf (sap-ref-word ptr offset) 0)
231 (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
232 (look (ptr offset count)
233 (declare (type system-area-pointer ptr)
234 (type (unsigned-byte 16) offset)
235 (type (unsigned-byte 20) count)
236 (values (unsigned-byte 20)))
237 (cond ((>= (sap-int ptr) end-of-stack) 0)
238 ((= offset bytes-per-scrub-unit)
240 ((zerop (sap-ref-word ptr offset))
241 (look ptr (+ offset sb!vm:n-word-bytes) count))
243 (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
244 (declare (type sb!vm::word csp))
245 (scrub (int-sap (- csp initial-offset))
246 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
249 #!+stack-grows-downward-not-upward
250 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
251 (end-of-stack (+ (sap-int (sb!di::descriptor-sap sb!vm:*control-stack-start*))
252 sb!c:*backend-page-size*))
253 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
255 ((scrub (ptr offset count)
256 (declare (type system-area-pointer ptr)
257 (type (unsigned-byte 16) offset)
258 (type (unsigned-byte 20) count)
259 (values (unsigned-byte 20)))
260 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
261 (cond ((< (sap-int loc) end-of-stack) 0)
262 ((= offset bytes-per-scrub-unit)
263 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
265 (t ;; need to fix bug in %SET-STACK-REF
266 (setf (sap-ref-word loc 0) 0)
267 (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
268 (look (ptr offset count)
269 (declare (type system-area-pointer ptr)
270 (type (unsigned-byte 16) offset)
271 (type (unsigned-byte 20) count)
272 (values (unsigned-byte 20)))
273 (let ((loc (int-sap (- (sap-int ptr) offset))))
274 (cond ((< (sap-int loc) end-of-stack) 0)
275 ((= offset bytes-per-scrub-unit)
277 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
278 (look ptr (+ offset sb!vm:n-word-bytes) count))
280 (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
281 (declare (type sb!vm::word csp))
282 (scrub (int-sap (+ csp initial-offset))
283 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
286 ;;;; the default toplevel function
290 "a list of all the values returned by the most recent top level EVAL")
291 (defvar // nil #!+sb-doc "the previous value of /")
292 (defvar /// nil #!+sb-doc "the previous value of //")
293 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
294 (defvar ** nil #!+sb-doc "the previous value of *")
295 (defvar *** nil #!+sb-doc "the previous value of **")
296 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
297 (defvar ++ nil #!+sb-doc "the previous value of +")
298 (defvar +++ nil #!+sb-doc "the previous value of ++")
299 (defvar - nil #!+sb-doc "the form currently being evaluated")
301 (defun interactive-eval (form)
303 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
304 +++, ++, +, ///, //, /, and -."
307 (let ((results (multiple-value-list (eval form))))
318 ;; The bogon returned an unbound marker.
319 ;; FIXME: It would be safer to check every one of the values in RESULTS,
320 ;; instead of just the first one.
322 (cerror "Go on with * set to NIL."
323 "EVAL returned an unbound marker."))
326 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
327 ;;; output streams before proceeding.
328 (defun flush-standard-output-streams ()
329 (dolist (name '(*debug-io*
335 ;; FINISH-OUTPUT may block more easily than FORCE-OUTPUT
336 (force-output (symbol-value name)))
339 (defun process-init-file (specified-pathname default-function)
341 (let ((cookie (list)))
342 (flet ((process-stream (stream &optional pathname)
347 (error "Error during processing of ~
348 initialization file ~A:~%~% ~A"
349 (or pathname stream) e))))
350 (let ((form (read stream nil cookie)))
352 (return-from process-init-file nil)
355 :report "Ignore and continue processing.")))))
356 (if specified-pathname
357 (with-open-file (stream (parse-native-namestring specified-pathname)
358 :if-does-not-exist nil)
360 (process-stream stream (pathname stream))
361 (error "The specified init file ~S was not found."
362 specified-pathname)))
363 (let ((default (funcall default-function)))
365 (with-open-file (stream (pathname default) :if-does-not-exist nil)
367 (process-stream stream (pathname stream)))))))))
369 :report "Skip this initialization file.")))
371 (defun process-eval-options (eval-strings-or-forms)
372 (/show0 "handling --eval options")
373 (flet ((process-1 (string-or-form)
374 (etypecase string-or-form
376 (multiple-value-bind (expr pos) (read-from-string string-or-form)
377 (unless (eq string-or-form
378 (read-from-string string-or-form nil string-or-form
380 (error "More than one expression in ~S" string-or-form))
382 (flush-standard-output-streams)))
383 (cons (eval string-or-form) (flush-standard-output-streams)))))
385 (dolist (expr-as-string-or-form eval-strings-or-forms)
386 (/show0 "handling one --eval option")
390 (error "Error during processing of --eval ~
392 expr-as-string-or-form e))))
393 (process-1 expr-as-string-or-form))
395 :report "Ignore and continue with next --eval option.")))
397 :report "Skip rest of --eval options."))))
399 ;; Errors while processing the command line cause the system to QUIT,
400 ;; instead of trying to go into the Lisp debugger, because trying to
401 ;; go into the Lisp debugger would get into various annoying issues of
402 ;; where we should go after the user tries to return from the
404 (defun startup-error (control-string &rest args)
405 (format *error-output*
406 "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
409 (quit :unix-status 1))
411 ;;; the default system top level function
412 (defun toplevel-init ()
413 (/show0 "entering TOPLEVEL-INIT")
414 (let ( ;; value of --sysinit option
416 ;; t if --no-sysinit option given
418 ;; value of --userinit option
420 ;; t if --no-userinit option given
422 ;; values of --eval options, in reverse order; and also any
423 ;; other options (like --load) which're translated into --eval
425 ;; The values are stored as strings, so that they can be
426 ;; passed to READ only after their predecessors have been
427 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL
428 ;; form creates a package referred to in the next EVAL form,
429 ;; except for forms transformed from syntactically-sugary
430 ;; switches like --load and --disable-debugger.
432 ;; Has a --noprint option been seen?
434 ;; everything in *POSIX-ARGV* except for argv[0]=programname
435 (options (rest *posix-argv*)))
437 (declare (type list options))
439 (/show0 "done with outer LET in TOPLEVEL-INIT")
441 ;; FIXME: There are lots of ways for errors to happen around here
442 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
443 ;; READ an --eval string). Make sure that they're handled
446 ;; Process command line options.
447 (loop while options do
448 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
449 (let ((option (first options)))
450 (flet ((pop-option ()
454 "unexpected end of command line options"))))
455 (cond ((string= option "--sysinit")
458 (startup-error "multiple --sysinit options")
459 (setf sysinit (pop-option))))
460 ((string= option "--no-sysinit")
463 ((string= option "--userinit")
466 (startup-error "multiple --userinit options")
467 (setf userinit (pop-option))))
468 ((string= option "--no-userinit")
470 (setf no-userinit t))
471 ((string= option "--eval")
473 (push (pop-option) reversed-evals))
474 ((string= option "--load")
477 (list 'cl:load (native-pathname (pop-option)))
479 ((string= option "--noprint")
482 ((string= option "--disable-debugger")
484 (push (list 'sb!ext:disable-debugger) reversed-evals))
485 ((string= option "--end-toplevel-options")
489 ;; Anything we don't recognize as a toplevel
490 ;; option must be the start of user-level
491 ;; options.. except that if we encounter
492 ;; "--end-toplevel-options" after we gave up
493 ;; because we didn't recognize an option as a
494 ;; toplevel option, then the option we gave up on
495 ;; must have been an error. (E.g. in
496 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
497 ;; this test will let us detect that the string
498 ;; "--eval(b)" is an error.)
499 (if (find "--end-toplevel-options" options
501 (startup-error "bad toplevel option: ~S"
504 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
506 ;; Delete all the options that we processed, so that only
507 ;; user-level options are left visible to user code.
508 (setf (rest *posix-argv*) options)
510 ;; Handle initialization files.
511 (/show0 "handling initialization files in TOPLEVEL-INIT")
512 ;; This CATCH is needed for the debugger command TOPLEVEL to
514 (catch 'toplevel-catcher
515 ;; We wrap all the pre-REPL user/system customized startup
516 ;; code in a restart.
518 ;; (Why not wrap everything, even the stuff above, in this
519 ;; restart? Errors above here are basically command line
520 ;; or Unix environment errors, e.g. a missing file or a
521 ;; typo on the Unix command line, and you don't need to
522 ;; get into Lisp to debug them, you should just start over
523 ;; and do it right at the Unix level. Errors below here
524 ;; are generally errors in user Lisp code, and it might be
525 ;; helpful to let the user reach the REPL in order to help
526 ;; figure out what's going on.)
530 (process-init-file sysinit *sysinit-pathname-function*))
532 (process-init-file userinit *userinit-pathname-function*))
533 (process-eval-options (nreverse reversed-evals)))
535 :report "Skip to toplevel READ/EVAL/PRINT loop."
536 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
537 (values)) ; (no-op, just fall through)
539 :report "Quit SBCL (calling #'QUIT, killing the process)."
540 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
541 (quit :unix-status 1))))
543 ;; one more time for good measure, in case we fell out of the
544 ;; RESTART-CASE above before one of the flushes in the ordinary
545 ;; flow of control had a chance to operate
546 (flush-standard-output-streams)
548 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
549 (toplevel-repl noprint)
550 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
551 (critically-unreachable "after TOPLEVEL-REPL")))
553 ;;; hooks to support customized toplevels like ACL-style toplevel from
554 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
555 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
556 (defvar *repl-read-form-fun* #'repl-read-form-fun
558 "A function of two stream arguments IN and OUT for the toplevel REPL to
559 call: Return the next Lisp form to evaluate (possibly handling other magic --
560 like ACL-style keyword commands -- which precede the next Lisp form). The OUT
561 stream is there to support magic which requires issuing new prompts.")
562 (defvar *repl-prompt-fun* #'repl-prompt-fun
564 "A function of one argument STREAM for the toplevel REPL to call: Prompt
565 the user for input.")
566 (defvar *repl-fun-generator* (constantly #'repl-fun)
568 "A function of no arguments returning a function of one argument NOPRINT
569 that provides the REPL for the system. Assumes that *STANDARD-INPUT* and
570 *STANDARD-OUTPUT* are set up.")
572 ;;; read-eval-print loop for the default system toplevel
573 (defun toplevel-repl (noprint)
574 (/show0 "entering TOPLEVEL-REPL")
575 (let ((* nil) (** nil) (*** nil)
577 (+ nil) (++ nil) (+++ nil)
578 (/// nil) (// nil) (/ nil))
579 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
580 (let ((repl-fun (funcall *repl-fun-generator*)))
581 ;; Each REPL in a multithreaded world should have bindings of
582 ;; most CL specials (most critically *PACKAGE*).
583 (with-rebound-io-syntax
584 (handler-bind ((step-condition 'invoke-stepper))
585 (let ((*stepping* nil)
588 (/show0 "about to set up restarts in TOPLEVEL-REPL")
589 ;; CLHS recommends that there should always be an
590 ;; ABORT restart; we have this one here, and one per
593 (abort "~@<Exit debugger, returning to top level.~@:>")
594 (catch 'toplevel-catcher
595 #!-win32 (sb!unix::reset-signal-mask)
596 ;; In the event of a control-stack-exhausted-error, we
597 ;; should have unwound enough stack by the time we get
598 ;; here that this is now possible.
600 (sb!kernel::protect-control-stack-guard-page 1)
601 (funcall repl-fun noprint)
602 (critically-unreachable "after REPL"))))))))))
604 ;;; Our default REPL prompt is the minimal traditional one.
605 (defun repl-prompt-fun (stream)
607 (write-string "* " stream)) ; arbitrary but customary REPL prompt
609 ;;; Our default form reader does relatively little magic, but does
610 ;;; handle the Unix-style EOF-is-end-of-process convention.
611 (defun repl-read-form-fun (in out)
612 (declare (type stream in out) (ignore out))
613 (let* ((eof-marker (cons nil nil))
614 (form (read in nil eof-marker)))
615 (if (eq form eof-marker)
619 (defun repl-fun (noprint)
620 (/show0 "entering REPL")
624 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
625 (scrub-control-stack)
626 (sb!thread::get-foreground)
628 (flush-standard-output-streams)
629 (funcall *repl-prompt-fun* *standard-output*)
630 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
631 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
632 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
633 ;; odd. But maybe there *is* a valid reason in some
634 ;; circumstances? perhaps some deadlock issue when being driven
635 ;; by another process or something...)
636 (force-output *standard-output*))
637 (let* ((form (funcall *repl-read-form-fun*
640 (results (multiple-value-list (interactive-eval form))))
642 (dolist (result results)
645 ;; If we started stepping in the debugger we want to stop now.
649 ;;; a convenient way to get into the assembly-level debugger
651 (%primitive sb!c:halt))