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 'simple-type-error
144 :format-control "invalid argument to SLEEP: ~S"
145 :format-arguments (list n)
147 :expected-type '(real 0)))
148 (multiple-value-bind (sec usec)
151 (multiple-value-bind (sec frac)
153 (values sec (truncate frac 1e-6))))
154 (sb!unix:unix-select 0 0 0 0 sec usec))
157 ;;;; SCRUB-CONTROL-STACK
159 (defconstant bytes-per-scrub-unit 2048)
161 ;;; Zero the unused portion of the control stack so that old objects
162 ;;; are not kept alive because of uninitialized stack variables.
164 ;;; FIXME: Why do we need to do this instead of just letting GC read
165 ;;; the stack pointer and avoid messing with the unused portion of
166 ;;; the control stack? (Is this a multithreading thing where there's
167 ;;; one control stack and stack pointer per thread, and it might not
168 ;;; be easy to tell what a thread's stack pointer value is when
169 ;;; looking in from another thread?)
170 (defun scrub-control-stack ()
171 (declare (optimize (speed 3) (safety 0))
172 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
174 #!-x86 ; machines where stack grows upwards (I guess) -- WHN 19990906
176 ((scrub (ptr offset count)
177 (declare (type system-area-pointer ptr)
178 (type (unsigned-byte 16) offset)
179 (type (unsigned-byte 20) count)
180 (values (unsigned-byte 20)))
181 (cond ((= offset bytes-per-scrub-unit)
182 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
184 (setf (sap-ref-32 ptr offset) 0)
185 (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
186 (look (ptr offset count)
187 (declare (type system-area-pointer ptr)
188 (type (unsigned-byte 16) offset)
189 (type (unsigned-byte 20) count)
190 (values (unsigned-byte 20)))
191 (cond ((= offset bytes-per-scrub-unit)
193 ((zerop (sap-ref-32 ptr offset))
194 (look ptr (+ offset sb!vm:n-word-bytes) count))
196 (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
197 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
198 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
199 (declare (type (unsigned-byte 32) csp))
200 (scrub (int-sap (- csp initial-offset))
201 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
204 #!+x86 ;; (Stack grows downwards.)
206 ((scrub (ptr offset count)
207 (declare (type system-area-pointer ptr)
208 (type (unsigned-byte 16) offset)
209 (type (unsigned-byte 20) count)
210 (values (unsigned-byte 20)))
211 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
212 (cond ((= offset bytes-per-scrub-unit)
213 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
215 (t ;; need to fix bug in %SET-STACK-REF
216 (setf (sap-ref-32 loc 0) 0)
217 (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
218 (look (ptr offset count)
219 (declare (type system-area-pointer ptr)
220 (type (unsigned-byte 16) offset)
221 (type (unsigned-byte 20) count)
222 (values (unsigned-byte 20)))
223 (let ((loc (int-sap (- (sap-int ptr) offset))))
224 (cond ((= offset bytes-per-scrub-unit)
226 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
227 (look ptr (+ offset sb!vm:n-word-bytes) count))
229 (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
230 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
231 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
232 (declare (type (unsigned-byte 32) csp))
233 (scrub (int-sap (+ csp initial-offset))
234 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
237 ;;;; the default toplevel function
241 "a list of all the values returned by the most recent top level EVAL")
242 (defvar // nil #!+sb-doc "the previous value of /")
243 (defvar /// nil #!+sb-doc "the previous value of //")
244 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
245 (defvar ** nil #!+sb-doc "the previous value of *")
246 (defvar *** nil #!+sb-doc "the previous value of **")
247 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
248 (defvar ++ nil #!+sb-doc "the previous value of +")
249 (defvar +++ nil #!+sb-doc "the previous value of ++")
250 (defvar - nil #!+sb-doc "the form currently being evaluated")
252 (defun interactive-eval (form)
253 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
254 +++, ++, +, ///, //, /, and -."
256 (let ((results (multiple-value-list (eval form))))
267 ;; The bogon returned an unbound marker.
268 ;; FIXME: It would be safer to check every one of the values in RESULTS,
269 ;; instead of just the first one.
271 (cerror "Go on with * set to NIL."
272 "EVAL returned an unbound marker."))
275 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
276 ;;; output streams before proceeding.
277 (defun flush-standard-output-streams ()
278 (dolist (name '(*debug-io*
283 (finish-output (symbol-value name)))
286 ;;; the default system top level function
287 (defun toplevel-init ()
289 (/show0 "entering TOPLEVEL-INIT")
291 (let ((sysinit nil) ; value of --sysinit option
292 (userinit nil) ; value of --userinit option
293 (reversed-evals nil) ; values of --eval options, in reverse order; and
294 ; also --load options, translated into --eval
295 (noprint nil) ; Has a --noprint option been seen?
296 (noprogrammer nil) ; Has a --noprogrammer option been seen?
297 (options (rest *posix-argv*))) ; skipping program name
299 (/show0 "done with outer LET in TOPLEVEL-INIT")
301 ;; FIXME: There are lots of ways for errors to happen around here
302 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
303 ;; READ an --eval string). Make sure that they're handled
304 ;; reasonably. Also, perhaps all errors while parsing the command
305 ;; line should cause the system to QUIT, instead of trying to go
306 ;; into the Lisp debugger, since trying to go into the debugger
307 ;; gets into various annoying issues of where we should go after
308 ;; the user tries to return from the debugger.
310 ;; Parse command line options.
311 (loop while options do
312 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
313 (let ((option (first options)))
314 (flet ((pop-option ()
317 (error "unexpected end of command line options"))))
318 (cond ((string= option "--sysinit")
321 (error "multiple --sysinit options")
322 (setf sysinit (pop-option))))
323 ((string= option "--userinit")
326 (error "multiple --userinit options")
327 (setf userinit (pop-option))))
328 ((string= option "--eval")
330 (let ((eval-as-string (pop-option)))
331 (with-input-from-string (eval-stream eval-as-string)
332 (let* ((eof-marker (cons :eof :eof))
333 (eval (read eval-stream nil eof-marker))
334 (eof (read eval-stream nil eof-marker)))
335 (cond ((eq eval eof-marker)
336 (error "unable to parse ~S"
338 ((not (eq eof eof-marker))
339 (error "more than one expression in ~S"
342 (push eval reversed-evals)))))))
343 ((string= option "--load")
345 (push `(load ,(pop-option)) reversed-evals))
346 ((string= option "--noprint")
349 ((string= option "--noprogrammer")
351 (setf noprogrammer t))
352 ((string= option "--end-toplevel-options")
356 ;; Anything we don't recognize as a toplevel
357 ;; option must be the start of user-level
358 ;; options.. except that if we encounter
359 ;; "--end-toplevel-options" after we gave up
360 ;; because we didn't recognize an option as a
361 ;; toplevel option, then the option we gave up on
362 ;; must have been an error. (E.g. in
363 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
364 ;; this test will let us detect that the string
365 ;; "--eval(b)" is an error.)
366 (if (find "--end-toplevel-options" options
368 (error "bad toplevel option: ~S" (first options))
370 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
372 ;; Excise all the options that we processed, so that only
373 ;; user-level options are left visible to user code.
374 (setf (rest *posix-argv*) options)
376 ;; Handle --noprogrammer option. We intentionally do this
377 ;; early so that it will affect the handling of initialization
378 ;; files and --eval options.
379 (/show0 "handling --noprogrammer option in TOPLEVEL-INIT")
381 (setf *debugger-hook* 'noprogrammer-debugger-hook-fun
382 *debug-io* *error-output*))
384 ;; Handle initialization files.
385 (/show0 "handling initialization files in TOPLEVEL-INIT")
386 (flet (;; If any of POSSIBLE-INIT-FILE-NAMES names a real file,
387 ;; return its truename.
388 (probe-init-files (&rest possible-init-file-names)
389 (/show0 "entering PROBE-INIT-FILES")
392 (and (stringp x) (probe-file x)))
393 possible-init-file-names)
394 (/show0 "leaving PROBE-INIT-FILES"))))
395 (let* ((sbcl-home (posix-getenv "SBCL_HOME"))
396 (sysinit-truename (if sbcl-home
397 (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
412 ;; We wrap all the pre-REPL user/system customized startup code
415 ;; (Why not wrap everything, even the stuff above, in this
416 ;; restart? Errors above here are basically command line or
417 ;; Unix environment errors, e.g. a missing file or a typo on
418 ;; the Unix command line, and you don't need to get into Lisp
419 ;; to debug them, you should just start over and do it right
420 ;; at the Unix level. Errors below here are generally errors
421 ;; in user Lisp code, and it might be helpful to let the user
422 ;; reach the REPL in order to help figure out what's going
426 (flet ((process-init-file (truename)
428 (unless (load truename)
429 (error "~S was not successfully loaded." truename))
430 (flush-standard-output-streams))))
431 (process-init-file sysinit-truename)
432 (process-init-file userinit-truename))
434 ;; Process --eval options.
435 (/show0 "handling --eval options in TOPLEVEL-INIT")
436 (dolist (eval (reverse reversed-evals))
437 (/show0 "handling one --eval option in TOPLEVEL-INIT")
439 (flush-standard-output-streams)))
442 "Continue anyway (skipping to toplevel read/eval/print loop)."
443 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
444 (values)) ; (no-op, just fall through)
446 :report "Quit SBCL (calling #'QUIT, killing the process)."
447 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
450 ;; one more time for good measure, in case we fell out of the
451 ;; RESTART-CASE above before one of the flushes in the ordinary
452 ;; flow of control had a chance to operate
453 (flush-standard-output-streams)
455 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
456 (toplevel-repl noprint)
457 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
458 (critically-unreachable "after TOPLEVEL-REPL"))))
460 ;;; read-eval-print loop for the default system toplevel
461 (defun toplevel-repl (noprint)
462 (/show0 "entering TOPLEVEL-REPL")
463 (let ((* nil) (** nil) (*** nil)
465 (+ nil) (++ nil) (+++ nil)
466 (/// nil) (// nil) (/ nil))
467 ;; WITH-SIMPLE-RESTART doesn't actually restart its body as some
468 ;; (like WHN for an embarrassingly long time ca. 2001-12-07) might
469 ;; think, but instead drops control back out at the end. So when a
470 ;; TOPLEVEL or outermost-ABORT restart happens, we need this outer
471 ;; LOOP wrapper to grab control and start over again. (And it also
472 ;; wraps CATCH 'TOPLEVEL-CATCHER for similar reasons.)
474 (/show0 "about to set up restarts in TOPLEVEL-REPL")
475 ;; There should only be one TOPLEVEL restart, and it's here, so
476 ;; restarting at TOPLEVEL always bounces you all the way out here.
477 (with-simple-restart (toplevel
478 "Restart at toplevel READ/EVAL/PRINT loop.")
479 ;; We add a new ABORT restart for every debugger level, so
480 ;; restarting at ABORT in a nested debugger gets you out to the
481 ;; innermost enclosing debugger, and only when you're in the
482 ;; outermost, unnested debugger level does restarting at ABORT
483 ;; get you out to here.
486 "Reduce debugger level (leaving debugger, returning to toplevel).")
487 (catch 'toplevel-catcher
488 (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
490 (critically-unreachable "after REPL")))))))
492 (defun repl (noprint)
493 (/show0 "entering REPL")
494 (let ((eof-marker (cons :eof nil)))
496 ;; FIXME: It seems bad to have GC behavior depend on scrubbing the
497 ;; control stack before each interactive command. Isn't there some
498 ;; way we can convince the GC to just ignore dead areas of the
499 ;; control stack, so that we don't need to rely on this half-measure?
500 (scrub-control-stack)
503 (write-string "* ") ; arbitrary but customary REPL prompt
504 (flush-standard-output-streams))
505 (let ((form (read *standard-input* nil eof-marker)))
506 (cond ((eq form eof-marker)
507 (/show0 "doing QUIT for EOF in REPL")
510 (let ((results (multiple-value-list (interactive-eval form))))
512 (dolist (result results)
514 (prin1 result))))))))))
516 (defun noprogrammer-debugger-hook-fun (condition old-debugger-hook)
517 (declare (ignore old-debugger-hook))
518 (flet ((failure-quit (&key recklessly-p)
519 (/show0 "in FAILURE-QUIT (in noprogrammer debugger hook)")
520 (quit :unix-status 1 :recklessly-p recklessly-p)))
521 ;; This HANDLER-CASE is here mostly to stop output immediately
522 ;; (and fall through to QUIT) when there's an I/O error. Thus,
523 ;; when we're run under a shell script or something, we can die
524 ;; cleanly when the script dies (and our pipes are cut), instead
525 ;; of falling into ldb or something messy like that.
528 (format *error-output*
529 "~&~@<unhandled condition (of type ~S): ~2I~_~A~:>~2%"
532 ;; Flush *ERROR-OUTPUT* even before the BACKTRACE, so that
533 ;; even if we hit an error within BACKTRACE (e.g. a bug in
534 ;; the debugger's own frame-walking code, or a bug in a user
535 ;; PRINT-OBJECT method) we'll at least have the CONDITION
536 ;; printed out before we die.
537 (finish-output *error-output*)
538 ;; (Where to truncate the BACKTRACE is of course arbitrary, but
539 ;; it seems as though we should at least truncate it somewhere.)
540 (sb!debug:backtrace 128 *error-output*)
541 (format *error-output*
542 "~%unhandled condition in --noprogrammer mode, quitting~%")
543 (finish-output *error-output*)
546 ;; We IGNORE-ERRORS here because even %PRIMITIVE PRINT can
547 ;; fail when our output streams are blown away, as e.g. when
548 ;; we're running under a Unix shell script and it dies somehow
549 ;; (e.g. because of a SIGINT). In that case, we might as well
550 ;; just give it up for a bad job, and stop trying to notify
551 ;; the user of anything.
553 ;; Actually, the only way I've run across to exercise the
554 ;; problem is to have more than one layer of shell script.
555 ;; I have a shell script which does
556 ;; time nice -10 sh make.sh "$1" 2>&1 | tee make.tmp
557 ;; and the problem occurs when I interrupt this with Ctrl-C
558 ;; under Linux 2.2.14-5.0 and GNU bash, version 1.14.7(1).
559 ;; I haven't figured out whether it's bash, time, tee, Linux, or
560 ;; what that is responsible, but that it's possible at all
561 ;; means that we should IGNORE-ERRORS here. -- WHN 2001-04-24
563 (%primitive print "Argh! error within --noprogrammer error handling"))
564 (failure-quit :recklessly-p t)))))
566 ;;; a convenient way to get into the assembly-level debugger
568 (%primitive sb!c:halt))