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 *gc-inhibit* *need-to-collect-garbage*
29 *before-gc-hooks* *after-gc-hooks*
30 #!+x86 *pseudo-atomic-atomic*
31 #!+x86 *pseudo-atomic-interrupted*
32 sb!unix::*interrupts-enabled*
33 sb!unix::*interrupt-pending*
34 *type-system-initialized*))
36 (defvar *cold-init-complete-p*)
38 ;;; counts of nested errors (with internal errors double-counted)
39 (defvar *maximum-error-depth*)
40 (defvar *current-error-depth*)
45 (defvar *step-form-stack* nil
46 "A place for single steppers to push information about
47 STEP-FORM-CONDITIONS avaiting the corresponding
48 STEP-VALUES-CONDITIONS. The system is guaranteed to empty the stack
49 when stepping terminates, so that it remains in sync, but doesn't
50 modify it in any other way: it is provided for implmentors of single
51 steppers to maintain contextual information.")
53 ;;;; miscellaneous utilities for working with with TOPLEVEL
55 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
56 ;;; by QUIT) is caught and any final processing and return codes are
57 ;;; handled appropriately.
58 (defmacro handling-end-of-the-world (&body body)
59 (with-unique-names (caught)
60 `(let ((,caught (catch '%end-of-the-world
61 (/show0 "inside CATCH '%END-OF-THE-WORLD")
63 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
64 (flush-standard-output-streams)
65 (sb!thread::terminate-session)
66 (/show0 "calling UNIX-EXIT")
67 (sb!unix:unix-exit ,caught))))
69 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
71 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
73 (defmacro infinite-error-protect (&rest forms)
74 `(unless (infinite-error-protector)
75 (/show0 "back from INFINITE-ERROR-PROTECTOR")
76 (let ((*current-error-depth* (1+ *current-error-depth*)))
77 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
78 ;; arbitrary truncation
79 #!+sb-show (sb!debug:backtrace 8)
82 ;;; a helper function for INFINITE-ERROR-PROTECT
83 (defun infinite-error-protector ()
84 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
85 (/hexstr *current-error-depth*)
86 (cond ((not *cold-init-complete-p*)
87 (%primitive print "Argh! error in cold init, halting")
88 (%primitive sb!c:halt))
89 ((or (not (boundp '*current-error-depth*))
90 (not (realp *current-error-depth*))
91 (not (boundp '*maximum-error-depth*))
92 (not (realp *maximum-error-depth*)))
93 (%primitive print "Argh! corrupted error depth, halting")
94 (%primitive sb!c:halt))
95 ((> *current-error-depth* *maximum-error-depth*)
96 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
97 (/hexstr *maximum-error-depth*)
98 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
100 *current-error-depth*
102 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
105 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
108 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
109 ;;; one point (shown below), and SBCL cross-compiled it without
110 ;;; warning about FORMS being undefined. Check whether that problem
111 ;;; (missing warning) is repeatable in the final system and if so, fix
114 (defun infinite-error-protector ()
115 `(cond ((not *cold-init-complete-p*)
116 (%primitive print "Argh! error in cold init, halting")
117 (%primitive sb!c:halt))
118 ((or (not (boundp '*current-error-depth*))
119 (not (realp *current-error-depth*))
120 (not (boundp '*maximum-error-depth*))
121 (not (realp *maximum-error-depth*)))
122 (%primitive print "Argh! corrupted error depth, halting")
123 (%primitive sb!c:halt))
124 ((> *current-error-depth* *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.")
133 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
137 ;;;; miscellaneous external functions
141 "This function causes execution to be suspended for N seconds. N may
142 be any non-negative, non-complex number."
143 (when (or (not (realp n))
145 (error 'simple-type-error
146 :format-control "invalid argument to SLEEP: ~S"
147 :format-arguments (list n)
149 :expected-type '(real 0)))
150 (multiple-value-bind (sec usec)
153 (multiple-value-bind (sec frac)
155 (values sec (truncate frac 1e-6))))
156 (sb!unix:unix-select 0 0 0 0 sec usec))
159 ;;;; SCRUB-CONTROL-STACK
161 (defconstant bytes-per-scrub-unit 2048)
163 ;;; Zero the unused portion of the control stack so that old objects
164 ;;; are not kept alive because of uninitialized stack variables.
166 ;;; "To summarize the problem, since not all allocated stack frame
167 ;;; slots are guaranteed to be written by the time you call an another
168 ;;; function or GC, there may be garbage pointers retained in your
169 ;;; dead stack locations. The stack scrubbing only affects the part
170 ;;; of the stack from the SP to the end of the allocated stack."
171 ;;; - ram, on cmucl-imp, Tue, 25 Sep 2001
173 ;;; So, as an (admittedly lame) workaround, from time to time we call
174 ;;; scrub-control-stack to zero out all the unused portion. This is
175 ;;; supposed to happen when the stack is mostly empty, so that we have
176 ;;; a chance of clearing more of it: callers are currently (2002.07.18)
179 (defun scrub-control-stack ()
180 (declare (optimize (speed 3) (safety 0))
181 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
183 #!-stack-grows-downward-not-upward
184 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
185 (initial-offset (logand csp (1- bytes-per-scrub-unit)))
187 (- (sb!vm:fixnumize sb!vm:*control-stack-end*)
188 sb!c:*backend-page-size*)))
190 ((scrub (ptr offset count)
191 (declare (type system-area-pointer ptr)
192 (type (unsigned-byte 16) offset)
193 (type (unsigned-byte 20) count)
194 (values (unsigned-byte 20)))
195 (cond ((>= (sap-int ptr) end-of-stack) 0)
196 ((= offset bytes-per-scrub-unit)
197 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
199 (setf (sap-ref-32 ptr offset) 0)
200 (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
201 (look (ptr offset count)
202 (declare (type system-area-pointer ptr)
203 (type (unsigned-byte 16) offset)
204 (type (unsigned-byte 20) count)
205 (values (unsigned-byte 20)))
206 (cond ((>= (sap-int ptr) end-of-stack) 0)
207 ((= offset bytes-per-scrub-unit)
209 ((zerop (sap-ref-32 ptr offset))
210 (look ptr (+ offset sb!vm:n-word-bytes) count))
212 (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
213 (declare (type (unsigned-byte 32) csp))
214 (scrub (int-sap (- csp initial-offset))
215 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
218 #!+stack-grows-downward-not-upward
219 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
220 (end-of-stack (+ (sb!vm:fixnumize sb!vm:*control-stack-start*)
221 sb!c:*backend-page-size*))
222 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
224 ((scrub (ptr offset count)
225 (declare (type system-area-pointer ptr)
226 (type (unsigned-byte 16) offset)
227 (type (unsigned-byte 20) count)
228 (values (unsigned-byte 20)))
229 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
230 (cond ((< (sap-int loc) end-of-stack) 0)
231 ((= offset bytes-per-scrub-unit)
232 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
234 (t ;; need to fix bug in %SET-STACK-REF
235 (setf (sap-ref-32 loc 0) 0)
236 (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
237 (look (ptr offset count)
238 (declare (type system-area-pointer ptr)
239 (type (unsigned-byte 16) offset)
240 (type (unsigned-byte 20) count)
241 (values (unsigned-byte 20)))
242 (let ((loc (int-sap (- (sap-int ptr) offset))))
243 (cond ((< (sap-int loc) end-of-stack) 0)
244 ((= offset bytes-per-scrub-unit)
246 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
247 (look ptr (+ offset sb!vm:n-word-bytes) count))
249 (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
250 (declare (type (unsigned-byte 32) csp))
251 (scrub (int-sap (+ csp initial-offset))
252 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
255 ;;;; the default toplevel function
259 "a list of all the values returned by the most recent top level EVAL")
260 (defvar // nil #!+sb-doc "the previous value of /")
261 (defvar /// nil #!+sb-doc "the previous value of //")
262 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
263 (defvar ** nil #!+sb-doc "the previous value of *")
264 (defvar *** nil #!+sb-doc "the previous value of **")
265 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
266 (defvar ++ nil #!+sb-doc "the previous value of +")
267 (defvar +++ nil #!+sb-doc "the previous value of ++")
268 (defvar - nil #!+sb-doc "the form currently being evaluated")
270 (defun interactive-eval (form)
271 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
272 +++, ++, +, ///, //, /, and -."
277 (make-null-interactive-lexenv)))))
288 ;; The bogon returned an unbound marker.
289 ;; FIXME: It would be safer to check every one of the values in RESULTS,
290 ;; instead of just the first one.
292 (cerror "Go on with * set to NIL."
293 "EVAL returned an unbound marker."))
296 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
297 ;;; output streams before proceeding.
298 (defun flush-standard-output-streams ()
299 (dolist (name '(*debug-io*
304 (finish-output (symbol-value name)))
307 ;;; the default system top level function
308 (defun toplevel-init ()
310 (/show0 "entering TOPLEVEL-INIT")
311 (sb!thread::init-job-control)
312 (sb!thread::get-foreground)
313 (let (;; value of --sysinit option
315 ;; value of --userinit option
317 ;; values of --eval options, in reverse order; and also any
318 ;; other options (like --load) which're translated into --eval
320 ;; The values are stored as strings, so that they can be
321 ;; passed to READ only after their predecessors have been
322 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL
323 ;; form creates a package referred to in the next EVAL form.
325 ;; Has a --noprint option been seen?
327 ;; everything in *POSIX-ARGV* except for argv[0]=programname
328 (options (rest *posix-argv*)))
330 (declare (type list options))
332 (/show0 "done with outer LET in TOPLEVEL-INIT")
334 ;; FIXME: There are lots of ways for errors to happen around here
335 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
336 ;; READ an --eval string). Make sure that they're handled
339 ;; Process command line options.
340 (flet (;; Errors while processing the command line cause the system
341 ;; to QUIT, instead of trying to go into the Lisp debugger,
342 ;; because trying to go into the Lisp debugger would get
343 ;; into various annoying issues of where we should go after
344 ;; the user tries to return from the debugger.
345 (startup-error (control-string &rest args)
348 "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
351 (quit :unix-status 1)))
352 (loop while options do
353 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
354 (let ((option (first options)))
355 (flet ((pop-option ()
359 "unexpected end of command line options"))))
360 (cond ((string= option "--sysinit")
363 (startup-error "multiple --sysinit options")
364 (setf sysinit (pop-option))))
365 ((string= option "--userinit")
368 (startup-error "multiple --userinit options")
369 (setf userinit (pop-option))))
370 ((string= option "--eval")
372 (push (pop-option) reversed-evals))
373 ((string= option "--load")
376 ;; FIXME: see BUG 296
377 (concatenate 'string "(|LOAD| \"" (pop-option) "\")")
379 ((string= option "--noprint")
382 ;; FIXME: --noprogrammer was deprecated in 0.7.5, and
383 ;; in a year or so this backwards compatibility can
385 ((string= option "--noprogrammer")
386 (warn "treating deprecated --noprogrammer as --disable-debugger")
388 (push "(|DISABLE-DEBUGGER|)" reversed-evals))
389 ((string= option "--disable-debugger")
391 (push "(|DISABLE-DEBUGGER|)" reversed-evals))
392 ((string= option "--end-toplevel-options")
396 ;; Anything we don't recognize as a toplevel
397 ;; option must be the start of user-level
398 ;; options.. except that if we encounter
399 ;; "--end-toplevel-options" after we gave up
400 ;; because we didn't recognize an option as a
401 ;; toplevel option, then the option we gave up on
402 ;; must have been an error. (E.g. in
403 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
404 ;; this test will let us detect that the string
405 ;; "--eval(b)" is an error.)
406 (if (find "--end-toplevel-options" options
408 (startup-error "bad toplevel option: ~S"
411 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
413 ;; Delete all the options that we processed, so that only
414 ;; user-level options are left visible to user code.
415 (setf (rest *posix-argv*) options)
417 ;; Handle initialization files.
418 (/show0 "handling initialization files in TOPLEVEL-INIT")
419 (flet (;; shared idiom for searching for SYSINITish and
421 (probe-init-files (explicitly-specified-init-file-name
422 &rest default-init-file-names)
423 (declare (type list default-init-file-names))
424 (if explicitly-specified-init-file-name
425 (or (probe-file explicitly-specified-init-file-name)
426 (startup-error "The file ~S was not found."
427 explicitly-specified-init-file-name))
429 (and (stringp x) (probe-file x)))
430 default-init-file-names)))
431 ;; shared idiom for creating default names for
432 ;; SYSINITish and USERINITish files
433 (init-file-name (maybe-dir-name basename)
435 (concatenate 'string maybe-dir-name "/" basename))))
436 (let ((sysinit-truename
437 (probe-init-files sysinit
438 (init-file-name (posix-getenv "SBCL_HOME")
442 (probe-init-files userinit
443 (init-file-name (posix-getenv "HOME")
446 ;; We wrap all the pre-REPL user/system customized startup code
449 ;; (Why not wrap everything, even the stuff above, in this
450 ;; restart? Errors above here are basically command line or
451 ;; Unix environment errors, e.g. a missing file or a typo on
452 ;; the Unix command line, and you don't need to get into Lisp
453 ;; to debug them, you should just start over and do it right
454 ;; at the Unix level. Errors below here are generally errors
455 ;; in user Lisp code, and it might be helpful to let the user
456 ;; reach the REPL in order to help figure out what's going
460 (flet ((process-init-file (truename)
462 (unless (load truename)
463 (error "~S was not successfully loaded."
465 (flush-standard-output-streams))))
466 (process-init-file sysinit-truename)
467 (process-init-file userinit-truename))
469 ;; Process --eval options.
470 (/show0 "handling --eval options in TOPLEVEL-INIT")
471 (dolist (expr-as-string (reverse reversed-evals))
472 (/show0 "handling one --eval option in TOPLEVEL-INIT")
473 (let ((expr (with-input-from-string (eval-stream
475 (let* ((eof-marker (cons :eof :eof))
476 (result (read eval-stream
479 (eof (read eval-stream nil eof-marker)))
480 (cond ((eq result eof-marker)
481 (error "unable to parse ~S"
483 ((not (eq eof eof-marker))
485 "more than one expression in ~S"
490 (flush-standard-output-streams))))
493 "Continue anyway (skipping to toplevel read/eval/print loop)."
494 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
495 (values)) ; (no-op, just fall through)
497 :report "Quit SBCL (calling #'QUIT, killing the process)."
498 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
501 ;; one more time for good measure, in case we fell out of the
502 ;; RESTART-CASE above before one of the flushes in the ordinary
503 ;; flow of control had a chance to operate
504 (flush-standard-output-streams)
506 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
507 (toplevel-repl noprint)
508 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
509 (critically-unreachable "after TOPLEVEL-REPL")))))
511 ;;; hooks to support customized toplevels like ACL-style toplevel from
512 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
513 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
514 (defvar *repl-read-form-fun* #'repl-read-form-fun
515 "a function of two stream arguments IN and OUT for the toplevel REPL to
516 call: Return the next Lisp form to evaluate (possibly handling other
517 magic -- like ACL-style keyword commands -- which precede the next
518 Lisp form). The OUT stream is there to support magic which requires
519 issuing new prompts.")
520 (defvar *repl-prompt-fun* #'repl-prompt-fun
521 "a function of one argument STREAM for the toplevel REPL to call: Prompt
522 the user for input.")
523 (defvar *repl-fun-generator* (constantly #'repl-fun)
524 "a function of no arguments returning a function of one argument
525 NOPRINT that provides the REPL for the system. Assumes that
526 *STANDARD-INPUT* and *STANDARD-OUTPUT* are set up.")
528 ;;; read-eval-print loop for the default system toplevel
529 (defun toplevel-repl (noprint)
530 (/show0 "entering TOPLEVEL-REPL")
531 (let ((* nil) (** nil) (*** nil)
533 (+ nil) (++ nil) (+++ nil)
534 (/// nil) (// nil) (/ nil))
535 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
536 (let ((repl-fun (funcall *repl-fun-generator*)))
537 ;; Each REPL in a multithreaded world should have bindings of
538 ;; most CL specials (most critically *PACKAGE*).
539 (with-rebound-io-syntax
540 (handler-bind ((step-condition 'invoke-stepper))
541 (let ((*stepping* nil)
543 ;; WITH-SIMPLE-RESTART doesn't actually restart its body as
544 ;; some (like WHN for an embarrassingly long time
545 ;; ca. 2001-12-07) might think, but instead drops control back
546 ;; out at the end. So when a TOPLEVEL or outermost-ABORT
547 ;; restart happens, we need this outer LOOP wrapper to grab
548 ;; control and start over again. (And it also wraps CATCH
549 ;; 'TOPLEVEL-CATCHER for similar reasons.)
551 (/show0 "about to set up restarts in TOPLEVEL-REPL")
552 ;; There should only be one TOPLEVEL restart, and it's here,
553 ;; so restarting at TOPLEVEL always bounces you all the way
555 (with-simple-restart (toplevel
556 "Restart at toplevel READ/EVAL/PRINT loop.")
557 ;; We add a new ABORT restart for every debugger level, so
558 ;; restarting at ABORT in a nested debugger gets you out to
559 ;; the innermost enclosing debugger, and only when you're
560 ;; in the outermost, unnested debugger level does
561 ;; restarting at ABORT get you out to here.
563 (abort "~@<Reduce debugger level (leaving debugger, ~
564 returning to toplevel).~@:>")
565 (catch 'toplevel-catcher
566 (sb!unix::reset-signal-mask)
567 ;; In the event of a control-stack-exhausted-error, we
568 ;; should have unwound enough stack by the time we get
569 ;; here that this is now possible.
570 (sb!kernel::protect-control-stack-guard-page 1)
571 (funcall repl-fun noprint)
572 (critically-unreachable "after REPL")))))))))))
574 ;;; Our default REPL prompt is the minimal traditional one.
575 (defun repl-prompt-fun (stream)
577 (write-string "* " stream)) ; arbitrary but customary REPL prompt
579 ;;; Our default form reader does relatively little magic, but does
580 ;;; handle the Unix-style EOF-is-end-of-process convention.
581 (defun repl-read-form-fun (in out)
582 (declare (type stream in out) (ignore out))
583 (let* ((eof-marker (cons nil nil))
584 (form (read in nil eof-marker)))
585 (if (eq form eof-marker)
589 (defun repl-fun (noprint)
590 (/show0 "entering REPL")
594 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
595 (scrub-control-stack)
596 (sb!thread::get-foreground)
598 (funcall *repl-prompt-fun* *standard-output*)
599 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
600 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
601 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
602 ;; odd. But maybe there *is* a valid reason in some
603 ;; circumstances? perhaps some deadlock issue when being driven
604 ;; by another process or something...)
605 (force-output *standard-output*))
606 (let* ((form (funcall *repl-read-form-fun*
609 (results (multiple-value-list (interactive-eval form))))
611 (dolist (result results)
614 ;; If we started stepping in the debugger we want to stop now.
618 ;;; a convenient way to get into the assembly-level debugger
620 (%primitive sb!c:halt))