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 (defconstant most-positive-fixnum #.sb!vm:*target-most-positive-fixnum*
18 "the fixnum closest in value to positive infinity")
20 (defconstant most-negative-fixnum #.sb!vm:*target-most-negative-fixnum*
22 "the fixnum closest in value to negative infinity")
24 ;;;; magic specials initialized by GENESIS
26 ;;; FIXME: The DEFVAR here is redundant with the (DECLAIM (SPECIAL ..))
27 ;;; of all static symbols in early-impl.lisp.
29 (defvar *current-catch-block*)
30 (defvar *current-unwind-protect-block*)
31 (defvar *free-interrupt-context-index*))
33 ;;; specials initialized by !COLD-INIT
35 ;;; FIXME: These could be converted to DEFVARs.
36 (declaim (special *gc-inhibit* *already-maybe-gcing*
37 *need-to-collect-garbage*
39 *before-gc-hooks* *after-gc-hooks*
40 #!+x86 *pseudo-atomic-atomic*
41 #!+x86 *pseudo-atomic-interrupted*
42 sb!unix::*interrupts-enabled*
43 sb!unix::*interrupt-pending*
44 *type-system-initialized*))
46 (defvar *cold-init-complete-p*)
48 ;;; counts of nested errors (with internal errors double-counted)
49 (defvar *maximum-error-depth*)
50 (defvar *current-error-depth*)
52 ;;;; miscellaneous utilities for working with with TOPLEVEL
54 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
55 ;;; by QUIT) is caught and any final processing and return codes are
56 ;;; handled appropriately.
57 (defmacro handling-end-of-the-world (&body body)
58 (let ((caught (gensym "CAUGHT")))
59 `(let ((,caught (catch '%end-of-the-world
60 (/show0 "inside CATCH '%END-OF-THE-WORLD")
62 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
63 (flush-standard-output-streams)
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 #+sb-show (sb-debug:backtrace)
79 ;;; a helper function for INFINITE-ERROR-PROTECT
80 (defun infinite-error-protector ()
81 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
82 (/hexstr *current-error-depth*)
83 (cond ((not *cold-init-complete-p*)
84 (%primitive print "Argh! error in cold init, halting")
85 (%primitive sb!c:halt))
86 ((or (not (boundp '*current-error-depth*))
87 (not (realp *current-error-depth*))
88 (not (boundp '*maximum-error-depth*))
89 (not (realp *maximum-error-depth*)))
90 (%primitive print "Argh! corrupted error depth, halting")
91 (%primitive sb!c:halt))
92 ((> *current-error-depth* *maximum-error-depth*)
93 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
94 (/hexstr *maximum-error-depth*)
95 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
99 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
102 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
105 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
106 ;;; one point (shown below), and SBCL cross-compiled it without
107 ;;; warning about FORMS being undefined. Check whether that problem
108 ;;; (missing warning) is repeatable in the final system and if so, fix
111 (defun infinite-error-protector ()
112 `(cond ((not *cold-init-complete-p*)
113 (%primitive print "Argh! error in cold init, halting")
114 (%primitive sb!c:halt))
115 ((or (not (boundp '*current-error-depth*))
116 (not (realp *current-error-depth*))
117 (not (boundp '*maximum-error-depth*))
118 (not (realp *maximum-error-depth*)))
119 (%primitive print "Argh! corrupted error depth, halting")
120 (%primitive sb!c:halt))
121 ((> *current-error-depth* *maximum-error-depth*)
122 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
123 (error-error "Help! "
124 *current-error-depth*
126 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
130 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
134 ;;;; miscellaneous external functions
136 #!-mp ; The multi-processing version is defined in multi-proc.lisp.
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 "Invalid argument to SLEEP: ~S.~%~
144 Must be a non-negative, non-complex number."
146 (multiple-value-bind (sec usec)
149 (multiple-value-bind (sec frac)
151 (values sec(truncate frac 1e-6))))
152 (sb!unix:unix-select 0 0 0 0 sec usec))
155 ;;;; SCRUB-CONTROL-STACK
157 (defconstant bytes-per-scrub-unit 2048)
159 ;;; Zero the unused portion of the control stack so that old objects
160 ;;; are not kept alive because of uninitialized stack variables.
162 ;;; FIXME: Why do we need to do this instead of just letting GC read
163 ;;; the stack pointer and avoid messing with the unused portion of
164 ;;; the control stack? (Is this a multithreading thing where there's
165 ;;; one control stack and stack pointer per thread, and it might not
166 ;;; be easy to tell what a thread's stack pointer value is when
167 ;;; looking in from another thread?)
168 (defun scrub-control-stack ()
169 (declare (optimize (speed 3) (safety 0))
170 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
172 #!-x86 ; machines where stack grows upwards (I guess) -- WHN 19990906
174 ((scrub (ptr offset count)
175 (declare (type system-area-pointer ptr)
176 (type (unsigned-byte 16) offset)
177 (type (unsigned-byte 20) count)
178 (values (unsigned-byte 20)))
179 (cond ((= offset bytes-per-scrub-unit)
180 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
182 (setf (sap-ref-32 ptr offset) 0)
183 (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
184 (look (ptr offset count)
185 (declare (type system-area-pointer ptr)
186 (type (unsigned-byte 16) offset)
187 (type (unsigned-byte 20) count)
188 (values (unsigned-byte 20)))
189 (cond ((= offset bytes-per-scrub-unit)
191 ((zerop (sap-ref-32 ptr offset))
192 (look ptr (+ offset sb!vm:n-word-bytes) count))
194 (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
195 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
196 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
197 (declare (type (unsigned-byte 32) csp))
198 (scrub (int-sap (- csp initial-offset))
199 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
202 #!+x86 ;; (Stack grows downwards.)
204 ((scrub (ptr offset count)
205 (declare (type system-area-pointer ptr)
206 (type (unsigned-byte 16) offset)
207 (type (unsigned-byte 20) count)
208 (values (unsigned-byte 20)))
209 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
210 (cond ((= offset bytes-per-scrub-unit)
211 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
213 (t ;; need to fix bug in %SET-STACK-REF
214 (setf (sap-ref-32 loc 0) 0)
215 (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
216 (look (ptr offset count)
217 (declare (type system-area-pointer ptr)
218 (type (unsigned-byte 16) offset)
219 (type (unsigned-byte 20) count)
220 (values (unsigned-byte 20)))
221 (let ((loc (int-sap (- (sap-int ptr) offset))))
222 (cond ((= offset bytes-per-scrub-unit)
224 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
225 (look ptr (+ offset sb!vm:n-word-bytes) count))
227 (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
228 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
229 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
230 (declare (type (unsigned-byte 32) csp))
231 (scrub (int-sap (+ csp initial-offset))
232 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
235 ;;;; the default toplevel function
239 "a list of all the values returned by the most recent top level EVAL")
240 (defvar // nil #!+sb-doc "the previous value of /")
241 (defvar /// nil #!+sb-doc "the previous value of //")
242 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
243 (defvar ** nil #!+sb-doc "the previous value of *")
244 (defvar *** nil #!+sb-doc "the previous value of **")
245 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
246 (defvar ++ nil #!+sb-doc "the previous value of +")
247 (defvar +++ nil #!+sb-doc "the previous value of ++")
248 (defvar - nil #!+sb-doc "the form currently being evaluated")
250 ;;; the top level prompt string, or a function of no arguments that
251 ;;; returns a simple-string
252 (defvar *prompt* "* ")
254 (defun interactive-eval (form)
255 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
256 +++, ++, +, ///, //, /, and -."
258 (let ((results (multiple-value-list (eval form))))
269 ;; The bogon returned an unbound marker.
270 ;; FIXME: It would be safer to check every one of the values in RESULTS,
271 ;; instead of just the first one.
273 (cerror "Go on with * set to NIL."
274 "EVAL returned an unbound marker."))
277 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
278 ;;; output streams before proceeding.
279 (defun flush-standard-output-streams ()
280 (dolist (name '(*debug-io*
285 (finish-output (symbol-value name)))
288 ;;; the default system top level function
289 (defun toplevel-init ()
291 (/show0 "entering TOPLEVEL-INIT")
293 (let ((sysinit nil) ; value of --sysinit option
294 (userinit nil) ; value of --userinit option
295 (reversed-evals nil) ; values of --eval options, in reverse order
296 (noprint nil) ; Has a --noprint option been seen?
297 (noprogrammer nil) ; Has a --noprogammer option been seen?
298 (options (rest *posix-argv*))) ; skipping program name
300 (/show0 "done with outer LET in TOPLEVEL-INIT")
302 ;; FIXME: There are lots of ways for errors to happen around here
303 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
304 ;; READ an --eval string). Make sure that they're handled
305 ;; reasonably. Also, perhaps all errors while parsing the command
306 ;; line should cause the system to QUIT, instead of trying to go
307 ;; into the Lisp debugger.
309 ;; Parse command line options.
310 (loop while options do
311 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
312 (let ((option (first options)))
313 (flet ((pop-option ()
316 (error "unexpected end of command line options"))))
317 (cond ((string= option "--sysinit")
320 (error "multiple --sysinit options")
321 (setf sysinit (pop-option))))
322 ((string= option "--userinit")
325 (error "multiple --userinit options")
326 (setf userinit (pop-option))))
327 ((string= option "--eval")
329 (let ((eval-as-string (pop-option)))
330 (with-input-from-string (eval-stream eval-as-string)
331 (let* ((eof-marker (cons :eof :eof))
332 (eval (read eval-stream nil eof-marker))
333 (eof (read eval-stream nil eof-marker)))
334 (cond ((eq eval eof-marker)
335 (error "unable to parse ~S"
337 ((not (eq eof eof-marker))
338 (error "more than one expression in ~S"
341 (push eval reversed-evals)))))))
342 ((string= option "--noprint")
345 ((string= option "--noprogrammer")
347 (setf noprogrammer t))
348 ((string= option "--end-toplevel-options")
352 ;; Anything we don't recognize as a toplevel
353 ;; option must be the start of user-level
354 ;; options.. except that if we encounter
355 ;; "--end-toplevel-options" after we gave up
356 ;; because we didn't recognize an option as a
357 ;; toplevel option, then the option we gave up on
358 ;; must have been an error. (E.g. in
359 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
360 ;; this test will let us detect that the string
361 ;; "--eval(b)" is an error.)
362 (if (find "--end-toplevel-options" options
364 (error "bad toplevel option: ~S" (first options))
366 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
368 ;; Excise all the options that we processed, so that only
369 ;; user-level options are left visible to user code.
370 (setf (rest *posix-argv*) options)
372 ;; Handle --noprogrammer option. We intentionally do this
373 ;; early so that it will affect the handling of initialization
374 ;; files and --eval options.
375 (/show0 "handling --noprogrammer option in TOPLEVEL-INIT")
377 (setf *debugger-hook* 'noprogrammer-debugger-hook-fun
378 *debug-io* *error-output*))
380 ;; FIXME: Verify that errors in init files and/or --eval operations
381 ;; lead to reasonable behavior.
383 ;; Handle initialization files.
384 (/show0 "handling initialization files in TOPLEVEL-INIT")
385 (flet (;; If any of POSSIBLE-INIT-FILE-NAMES names a real file,
386 ;; return its truename.
387 (probe-init-files (&rest possible-init-file-names)
388 (/show0 "entering PROBE-INIT-FILES")
391 (and (stringp x) (probe-file x)))
392 possible-init-file-names)
393 (/show0 "leaving PROBE-INIT-FILES"))))
394 (let* ((sbcl-home (posix-getenv "SBCL_HOME"))
395 (sysinit-truename (if sbcl-home
396 (probe-init-files sysinit
401 (probe-init-files sysinit
403 "/usr/local/etc/sbclrc")))
404 (user-home (or (posix-getenv "HOME")
405 (error "The HOME environment variable is unbound, ~
406 so user init file can't be found.")))
407 (userinit-truename (probe-init-files userinit
413 ;; We wrap all the pre-REPL user/system customized startup code
416 ;; (Why not wrap everything, even the stuff above, in this
417 ;; restart? Errors above here are basically command line or
418 ;; Unix environment errors, e.g. a missing file or a typo on
419 ;; the Unix command line, and you don't need to get into Lisp
420 ;; to debug them, you should just start over and do it right
421 ;; at the Unix level. Errors below here are usually errors in
422 ;; user Lisp code, and it might be helpful to let the user
423 ;; reach the REPL in order to help figure out what's going on.)
425 (flet ((process-init-file (truename)
427 (unless (load truename)
428 (error "~S was not successfully loaded." truename))
429 (flush-standard-output-streams))))
430 (process-init-file sysinit-truename)
431 (process-init-file userinit-truename)
433 ;; Process --eval options.
434 (/show0 "handling --eval options in TOPLEVEL-INIT")
435 (dolist (eval (reverse reversed-evals))
436 (/show0 "handling one --eval option in TOPLEVEL-INIT")
438 (flush-standard-output-streams)))
441 "Continue anyway (skipping to toplevel read/eval/print loop)."
442 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
443 (values)) ; (no-op, just fall through)
445 :report "Quit SBCL (calling #'QUIT, killing the process)."
446 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
449 ;; one more time for good measure, in case we fell out of the
450 ;; RESTART-CASE above before one of the flushes in the ordinary
451 ;; flow of control had a chance to operate
452 (flush-standard-output-streams)
454 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
455 (toplevel-repl noprint)
456 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
457 (critically-unreachable "after TOPLEVEL-REPL"))))
459 ;;; read-eval-print loop for the default system toplevel
460 (defun toplevel-repl (noprint)
461 (/show0 "entering TOPLEVEL-REPL")
462 (let ((* nil) (** nil) (*** nil)
464 (+ nil) (++ nil) (+++ nil)
465 (/// nil) (// nil) (/ nil))
466 ;; WITH-SIMPLE-RESTART doesn't actually restart its body as some
467 ;; (like WHN for an embarrassingly long time ca. 2001-12-07) might
468 ;; think, but instead drops control back out at the end. So when a
469 ;; TOPLEVEL or outermost-ABORT restart happens, we need this outer
470 ;; LOOP wrapper to grab control and start over again. (And it also
471 ;; wraps CATCH 'TOPLEVEL-CATCHER for similar reasons.)
473 (/show0 "about to set up restarts in TOPLEVEL-REPL")
474 ;; There should only be one TOPLEVEL restart, and it's here, so
475 ;; restarting at TOPLEVEL always bounces you all the way out here.
476 (with-simple-restart (toplevel
477 "Restart at toplevel READ/EVAL/PRINT loop.")
478 ;; We add a new ABORT restart for every debugger level, so
479 ;; restarting at ABORT in a nested debugger gets you out to the
480 ;; innermost enclosing debugger, and only when you're in the
481 ;; outermost, unnested debugger level does restarting at ABORT
482 ;; get you out to here.
485 "Reduce debugger level (leaving debugger, returning to toplevel).")
486 (catch 'toplevel-catcher
487 (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
489 (critically-unreachable "after REPL")))))))
491 (defun repl (noprint)
492 (/show0 "entering REPL")
493 (let ((eof-marker (cons :eof nil)))
495 ;; FIXME: It seems bad to have GC behavior depend on scrubbing the
496 ;; control stack before each interactive command. Isn't there some
497 ;; way we can convince the GC to just ignore dead areas of the
498 ;; control stack, so that we don't need to rely on this
500 (scrub-control-stack)
503 (princ (if (functionp *prompt*)
506 (flush-standard-output-streams))
507 (let ((form (read *standard-input* nil eof-marker)))
508 (cond ((eq form eof-marker)
509 (/show0 "doing QUIT for EOF in REPL")
512 (let ((results (multiple-value-list (interactive-eval form))))
514 (dolist (result results)
516 (prin1 result))))))))))
518 (defun noprogrammer-debugger-hook-fun (condition old-debugger-hook)
519 (declare (ignore old-debugger-hook))
520 (flet ((failure-quit (&key recklessly-p)
521 (/show0 "in FAILURE-QUIT (in noprogrammer debugger hook)")
522 (quit :unix-status 1 :recklessly-p recklessly-p)))
523 ;; This HANDLER-CASE is here mostly to stop output immediately
524 ;; (and fall through to QUIT) when there's an I/O error. Thus,
525 ;; when we're run under a shell script or something, we can die
526 ;; cleanly when the script dies (and our pipes are cut), instead
527 ;; of falling into ldb or something messy like that.
530 (format *error-output*
531 "~&~@<unhandled condition (of type ~S): ~2I~_~A~:>~2%"
534 ;; Flush *ERROR-OUTPUT* even before the BACKTRACE, so that
535 ;; even if we hit an error within BACKTRACE (e.g. a bug in
536 ;; the debugger's own frame-walking code, or a bug in a user
537 ;; PRINT-OBJECT method) we'll at least have the CONDITION
538 ;; printed out before we die.
539 (finish-output *error-output*)
540 ;; (Where to truncate the BACKTRACE is of course arbitrary, but
541 ;; it seems as though we should at least truncate it somewhere.)
542 (sb!debug:backtrace 128 *error-output*)
543 (format *error-output*
544 "~%unhandled condition in --noprogrammer mode, quitting~%")
545 (finish-output *error-output*)
548 ;; We IGNORE-ERRORS here because even %PRIMITIVE PRINT can
549 ;; fail when our output streams are blown away, as e.g. when
550 ;; we're running under a Unix shell script and it dies somehow
551 ;; (e.g. because of a SIGINT). In that case, we might as well
552 ;; just give it up for a bad job, and stop trying to notify
553 ;; the user of anything.
555 ;; Actually, the only way I've run across to exercise the
556 ;; problem is to have more than one layer of shell script.
557 ;; I have a shell script which does
558 ;; time nice -10 sh make.sh "$1" 2>&1 | tee make.tmp
559 ;; and the problem occurs when I interrupt this with Ctrl-C
560 ;; under Linux 2.2.14-5.0 and GNU bash, version 1.14.7(1).
561 ;; I haven't figured out whether it's bash, time, tee, Linux, or
562 ;; what that is responsible, but that it's possible at all
563 ;; means that we should IGNORE-ERRORS here. -- WHN 2001-04-24
565 (%primitive print "Argh! error within --noprogrammer error handling"))
566 (failure-quit :recklessly-p t)))))
568 ;;; a convenient way to get into the assembly-level debugger
570 (%primitive sb!c:halt))