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*)
43 (defvar *step-form-stack* nil
44 "A place for single steppers to push information about
45 STEP-FORM-CONDITIONS avaiting the corresponding
46 STEP-VALUES-CONDITIONS. The system is guaranteed to empty the stack
47 when stepping terminates, so that it remains in sync, but doesn't
48 modify it in any other way: it is provided for implmentors of single
49 steppers to maintain contextual information.")
51 ;;;; miscellaneous utilities for working with with TOPLEVEL
53 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
54 ;;; by QUIT) is caught and any final processing and return codes are
55 ;;; handled appropriately.
56 (defmacro handling-end-of-the-world (&body body)
57 (with-unique-names (caught)
58 `(let ((,caught (catch '%end-of-the-world
59 (/show0 "inside CATCH '%END-OF-THE-WORLD")
61 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
62 (flush-standard-output-streams)
63 (sb!thread::terminate-session)
64 (/show0 "calling UNIX-EXIT")
65 (sb!unix:unix-exit ,caught))))
67 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
69 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
71 (defmacro infinite-error-protect (&rest forms)
72 `(unless (infinite-error-protector)
73 (/show0 "back from INFINITE-ERROR-PROTECTOR")
74 (let ((*current-error-depth* (1+ *current-error-depth*)))
75 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
76 ;; arbitrary truncation
77 #!+sb-show (sb!debug:backtrace 8)
80 ;;; a helper function for INFINITE-ERROR-PROTECT
81 (defun infinite-error-protector ()
82 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
83 (/hexstr *current-error-depth*)
84 (cond ((not *cold-init-complete-p*)
85 (%primitive print "Argh! error in cold init, halting")
86 (%primitive sb!c:halt))
87 ((or (not (boundp '*current-error-depth*))
88 (not (realp *current-error-depth*))
89 (not (boundp '*maximum-error-depth*))
90 (not (realp *maximum-error-depth*)))
91 (%primitive print "Argh! corrupted error depth, halting")
92 (%primitive sb!c:halt))
93 ((> *current-error-depth* *maximum-error-depth*)
94 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
95 (/hexstr *maximum-error-depth*)
96 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
100 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
103 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
106 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
107 ;;; one point (shown below), and SBCL cross-compiled it without
108 ;;; warning about FORMS being undefined. Check whether that problem
109 ;;; (missing warning) is repeatable in the final system and if so, fix
112 (defun infinite-error-protector ()
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 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
124 (error-error "Help! "
125 *current-error-depth*
127 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
131 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
135 ;;;; miscellaneous external functions
139 "This function causes execution to be suspended for N seconds. N may
140 be any non-negative, non-complex number."
141 (when (or (not (realp n))
143 (error 'simple-type-error
144 :format-control "invalid argument to SLEEP: ~S"
145 :format-arguments (list n)
147 :expected-type '(real 0)))
149 (multiple-value-bind (sec nsec)
152 (multiple-value-bind (sec frac)
154 (values sec (truncate frac 1e-9))))
155 (sb!unix:nanosleep sec nsec))
157 (sb!win32:millisleep (truncate (* n 1000)))
160 ;;;; SCRUB-CONTROL-STACK
162 (defconstant bytes-per-scrub-unit 2048)
164 ;;; Zero the unused portion of the control stack so that old objects
165 ;;; are not kept alive because of uninitialized stack variables.
167 ;;; "To summarize the problem, since not all allocated stack frame
168 ;;; slots are guaranteed to be written by the time you call an another
169 ;;; function or GC, there may be garbage pointers retained in your
170 ;;; dead stack locations. The stack scrubbing only affects the part
171 ;;; of the stack from the SP to the end of the allocated stack."
172 ;;; - ram, on cmucl-imp, Tue, 25 Sep 2001
174 ;;; So, as an (admittedly lame) workaround, from time to time we call
175 ;;; scrub-control-stack to zero out all the unused portion. This is
176 ;;; supposed to happen when the stack is mostly empty, so that we have
177 ;;; a chance of clearing more of it: callers are currently (2002.07.18)
180 (defun scrub-control-stack ()
181 (declare (optimize (speed 3) (safety 0))
182 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
184 #!-stack-grows-downward-not-upward
185 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
186 (initial-offset (logand csp (1- bytes-per-scrub-unit)))
188 (- (sap-int (sb!di::descriptor-sap sb!vm:*control-stack-end*))
189 sb!c:*backend-page-size*)))
191 ((scrub (ptr offset count)
192 (declare (type system-area-pointer ptr)
193 (type (unsigned-byte 16) offset)
194 (type (unsigned-byte 20) count)
195 (values (unsigned-byte 20)))
196 (cond ((>= (sap-int ptr) end-of-stack) 0)
197 ((= offset bytes-per-scrub-unit)
198 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
200 (setf (sap-ref-word ptr offset) 0)
201 (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
202 (look (ptr offset count)
203 (declare (type system-area-pointer ptr)
204 (type (unsigned-byte 16) offset)
205 (type (unsigned-byte 20) count)
206 (values (unsigned-byte 20)))
207 (cond ((>= (sap-int ptr) end-of-stack) 0)
208 ((= offset bytes-per-scrub-unit)
210 ((zerop (sap-ref-word ptr offset))
211 (look ptr (+ offset sb!vm:n-word-bytes) count))
213 (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
214 (declare (type sb!vm::word csp))
215 (scrub (int-sap (- csp initial-offset))
216 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
219 #!+stack-grows-downward-not-upward
220 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
221 (end-of-stack (+ (sap-int (sb!di::descriptor-sap sb!vm:*control-stack-start*))
222 sb!c:*backend-page-size*))
223 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
225 ((scrub (ptr offset count)
226 (declare (type system-area-pointer ptr)
227 (type (unsigned-byte 16) offset)
228 (type (unsigned-byte 20) count)
229 (values (unsigned-byte 20)))
230 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
231 (cond ((< (sap-int loc) end-of-stack) 0)
232 ((= offset bytes-per-scrub-unit)
233 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
235 (t ;; need to fix bug in %SET-STACK-REF
236 (setf (sap-ref-word loc 0) 0)
237 (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
238 (look (ptr offset count)
239 (declare (type system-area-pointer ptr)
240 (type (unsigned-byte 16) offset)
241 (type (unsigned-byte 20) count)
242 (values (unsigned-byte 20)))
243 (let ((loc (int-sap (- (sap-int ptr) offset))))
244 (cond ((< (sap-int loc) end-of-stack) 0)
245 ((= offset bytes-per-scrub-unit)
247 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
248 (look ptr (+ offset sb!vm:n-word-bytes) count))
250 (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
251 (declare (type sb!vm::word csp))
252 (scrub (int-sap (+ csp initial-offset))
253 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
256 ;;;; the default toplevel function
260 "a list of all the values returned by the most recent top level EVAL")
261 (defvar // nil #!+sb-doc "the previous value of /")
262 (defvar /// nil #!+sb-doc "the previous value of //")
263 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
264 (defvar ** nil #!+sb-doc "the previous value of *")
265 (defvar *** nil #!+sb-doc "the previous value of **")
266 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
267 (defvar ++ nil #!+sb-doc "the previous value of +")
268 (defvar +++ nil #!+sb-doc "the previous value of ++")
269 (defvar - nil #!+sb-doc "the form currently being evaluated")
271 (defun interactive-eval (form)
272 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
273 +++, ++, +, ///, //, /, and -."
276 (let ((results (multiple-value-list (eval form))))
287 ;; The bogon returned an unbound marker.
288 ;; FIXME: It would be safer to check every one of the values in RESULTS,
289 ;; instead of just the first one.
291 (cerror "Go on with * set to NIL."
292 "EVAL returned an unbound marker."))
295 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
296 ;;; output streams before proceeding.
297 (defun flush-standard-output-streams ()
298 (dolist (name '(*debug-io*
304 ;; FINISH-OUTPUT may block more easily than FORCE-OUTPUT
305 (force-output (symbol-value name)))
308 (defun process-init-file (truename)
311 (with-open-file (s truename :if-does-not-exist nil)
313 (let ((form (read s nil s)))
315 (return-from process-init-file nil)
319 (handler-bind ((error (lambda (e)
321 "Error during processing of ~
322 initialization file ~A:~%~% ~A"
326 :report "Ignore and continue processing.")))))
328 :report "Skip rest of initialization file."))))
330 (defun process-eval-options (eval-strings-or-forms)
331 (/show0 "handling --eval options")
332 (flet ((process-1 (string-or-form)
333 (etypecase string-or-form
335 (multiple-value-bind (expr pos) (read-from-string string-or-form)
336 (unless (eq string-or-form
337 (read-from-string string-or-form nil string-or-form
339 (error "More than one expression in ~S" string-or-form))
341 (flush-standard-output-streams)))
342 (cons (eval string-or-form) (flush-standard-output-streams)))))
344 (dolist (expr-as-string-or-form eval-strings-or-forms)
345 (/show0 "handling one --eval option")
349 (error "Error during processing of --eval ~
351 expr-as-string-or-form e))))
352 (process-1 expr-as-string-or-form))
354 :report "Ignore and continue with next --eval option.")))
356 :report "Skip rest of --eval options."))))
358 ;;; the default system top level function
359 (defun toplevel-init ()
360 (/show0 "entering TOPLEVEL-INIT")
361 (let (;; value of --sysinit option
363 ;; t if --no-sysinit option given
365 ;; value of --userinit option
367 ;; t if --no-userinit option given
369 ;; values of --eval options, in reverse order; and also any
370 ;; other options (like --load) which're translated into --eval
372 ;; The values are stored as strings, so that they can be
373 ;; passed to READ only after their predecessors have been
374 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL
375 ;; form creates a package referred to in the next EVAL form,
376 ;; except for forms transformed from syntactically-sugary
377 ;; switches like --load and --disable-debugger.
379 ;; Has a --noprint option been seen?
381 ;; everything in *POSIX-ARGV* except for argv[0]=programname
382 (options (rest *posix-argv*)))
384 (declare (type list options))
386 (/show0 "done with outer LET in TOPLEVEL-INIT")
388 ;; FIXME: There are lots of ways for errors to happen around here
389 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
390 ;; READ an --eval string). Make sure that they're handled
393 ;; Process command line options.
394 (flet (;; Errors while processing the command line cause the system
395 ;; to QUIT, instead of trying to go into the Lisp debugger,
396 ;; because trying to go into the Lisp debugger would get
397 ;; into various annoying issues of where we should go after
398 ;; the user tries to return from the debugger.
399 (startup-error (control-string &rest args)
402 "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
405 (quit :unix-status 1)))
406 (loop while options do
407 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
408 (let ((option (first options)))
409 (flet ((pop-option ()
413 "unexpected end of command line options"))))
414 (cond ((string= option "--sysinit")
417 (startup-error "multiple --sysinit options")
418 (setf sysinit (pop-option))))
419 ((string= option "--no-sysinit")
422 ((string= option "--userinit")
425 (startup-error "multiple --userinit options")
426 (setf userinit (pop-option))))
427 ((string= option "--no-userinit")
429 (setf no-userinit t))
430 ((string= option "--eval")
432 (push (pop-option) reversed-evals))
433 ((string= option "--load")
436 (list 'cl:load (native-pathname (pop-option)))
438 ((string= option "--noprint")
441 ((string= option "--disable-debugger")
443 (push (list 'sb!ext:disable-debugger) reversed-evals))
444 ((string= option "--end-toplevel-options")
448 ;; Anything we don't recognize as a toplevel
449 ;; option must be the start of user-level
450 ;; options.. except that if we encounter
451 ;; "--end-toplevel-options" after we gave up
452 ;; because we didn't recognize an option as a
453 ;; toplevel option, then the option we gave up on
454 ;; must have been an error. (E.g. in
455 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
456 ;; this test will let us detect that the string
457 ;; "--eval(b)" is an error.)
458 (if (find "--end-toplevel-options" options
460 (startup-error "bad toplevel option: ~S"
463 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
465 ;; Delete all the options that we processed, so that only
466 ;; user-level options are left visible to user code.
467 (setf (rest *posix-argv*) options)
469 ;; Handle initialization files.
470 (/show0 "handling initialization files in TOPLEVEL-INIT")
471 (flet (;; shared idiom for searching for SYSINITish and
473 (probe-init-files (explicitly-specified-init-file-name
474 &rest default-init-file-names)
475 (declare (type list default-init-file-names))
476 (if explicitly-specified-init-file-name
478 (parse-native-namestring
479 explicitly-specified-init-file-name))
480 (startup-error "The file ~S was not found."
481 explicitly-specified-init-file-name))
483 (and (pathnamep x) (probe-file x)))
484 default-init-file-names))))
485 (let ((sysinit-truename
486 (probe-init-files sysinit
487 (merge-pathnames (sbcl-homedir-pathname)
493 (sb!win32::get-folder-pathname
494 sb!win32::csidl_common_appdata)
497 (probe-init-files userinit
498 (merge-pathnames (user-homedir-pathname)
500 ;; This CATCH is needed for the debugger command TOPLEVEL to
502 (catch 'toplevel-catcher
503 ;; We wrap all the pre-REPL user/system customized startup
504 ;; code in a restart.
506 ;; (Why not wrap everything, even the stuff above, in this
507 ;; restart? Errors above here are basically command line
508 ;; or Unix environment errors, e.g. a missing file or a
509 ;; typo on the Unix command line, and you don't need to
510 ;; get into Lisp to debug them, you should just start over
511 ;; and do it right at the Unix level. Errors below here
512 ;; are generally errors in user Lisp code, and it might be
513 ;; helpful to let the user reach the REPL in order to help
514 ;; figure out what's going on.)
517 (unless no-sysinit (process-init-file sysinit-truename))
518 (unless no-userinit (process-init-file userinit-truename))
519 (process-eval-options (reverse reversed-evals)))
521 :report "Skip to toplevel READ/EVAL/PRINT loop."
522 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
523 (values)) ; (no-op, just fall through)
525 :report "Quit SBCL (calling #'QUIT, killing the process)."
526 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
529 ;; one more time for good measure, in case we fell out of the
530 ;; RESTART-CASE above before one of the flushes in the ordinary
531 ;; flow of control had a chance to operate
532 (flush-standard-output-streams)
534 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
535 (toplevel-repl noprint)
536 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
537 (critically-unreachable "after TOPLEVEL-REPL")))))
539 ;;; hooks to support customized toplevels like ACL-style toplevel from
540 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
541 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
542 (defvar *repl-read-form-fun* #'repl-read-form-fun
543 "a function of two stream arguments IN and OUT for the toplevel REPL to
544 call: Return the next Lisp form to evaluate (possibly handling other
545 magic -- like ACL-style keyword commands -- which precede the next
546 Lisp form). The OUT stream is there to support magic which requires
547 issuing new prompts.")
548 (defvar *repl-prompt-fun* #'repl-prompt-fun
549 "a function of one argument STREAM for the toplevel REPL to call: Prompt
550 the user for input.")
551 (defvar *repl-fun-generator* (constantly #'repl-fun)
552 "a function of no arguments returning a function of one argument
553 NOPRINT that provides the REPL for the system. Assumes that
554 *STANDARD-INPUT* and *STANDARD-OUTPUT* are set up.")
556 ;;; read-eval-print loop for the default system toplevel
557 (defun toplevel-repl (noprint)
558 (/show0 "entering TOPLEVEL-REPL")
559 (let ((* nil) (** nil) (*** nil)
561 (+ nil) (++ nil) (+++ nil)
562 (/// nil) (// nil) (/ nil))
563 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
564 (let ((repl-fun (funcall *repl-fun-generator*)))
565 ;; Each REPL in a multithreaded world should have bindings of
566 ;; most CL specials (most critically *PACKAGE*).
567 (with-rebound-io-syntax
568 (handler-bind ((step-condition 'invoke-stepper))
569 (let ((*stepping* nil)
572 (/show0 "about to set up restarts in TOPLEVEL-REPL")
573 ;; CLHS recommends that there should always be an
574 ;; ABORT restart; we have this one here, and one per
577 (abort "~@<Exit debugger, returning to top level.~@:>")
578 (catch 'toplevel-catcher
579 #!-win32 (sb!unix::reset-signal-mask)
580 ;; In the event of a control-stack-exhausted-error, we
581 ;; should have unwound enough stack by the time we get
582 ;; here that this is now possible.
584 (sb!kernel::protect-control-stack-guard-page 1)
585 (funcall repl-fun noprint)
586 (critically-unreachable "after REPL"))))))))))
588 ;;; Our default REPL prompt is the minimal traditional one.
589 (defun repl-prompt-fun (stream)
591 (write-string "* " stream)) ; arbitrary but customary REPL prompt
593 ;;; Our default form reader does relatively little magic, but does
594 ;;; handle the Unix-style EOF-is-end-of-process convention.
595 (defun repl-read-form-fun (in out)
596 (declare (type stream in out) (ignore out))
597 (let* ((eof-marker (cons nil nil))
598 (form (read in nil eof-marker)))
599 (if (eq form eof-marker)
603 (defun repl-fun (noprint)
604 (/show0 "entering REPL")
608 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
609 (scrub-control-stack)
610 (sb!thread::get-foreground)
612 (flush-standard-output-streams)
613 (funcall *repl-prompt-fun* *standard-output*)
614 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
615 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
616 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
617 ;; odd. But maybe there *is* a valid reason in some
618 ;; circumstances? perhaps some deadlock issue when being driven
619 ;; by another process or something...)
620 (force-output *standard-output*))
621 (let* ((form (funcall *repl-read-form-fun*
624 (results (multiple-value-list (interactive-eval form))))
626 (dolist (result results)
629 ;; If we started stepping in the debugger we want to stop now.
633 ;;; a convenient way to get into the assembly-level debugger
635 (%primitive sb!c:halt))