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.
30 (defvar *current-catch-block*)
31 (defvar *current-unwind-protect-block*)
32 (defvar *free-interrupt-context-index*))
34 ;;; specials initialized by !COLD-INIT
36 ;;; FIXME: These could be converted to DEFVARs, and the stuff shared
37 ;;; in both #!+GENGC and #!-GENGC (actually everything in #!+GENGC)
38 ;;; could be made non-conditional.
41 (special *gc-inhibit* *already-maybe-gcing*
42 *need-to-collect-garbage*
44 *before-gc-hooks* *after-gc-hooks*
45 #!+x86 *pseudo-atomic-atomic*
46 #!+x86 *pseudo-atomic-interrupted*
47 sb!unix::*interrupts-enabled*
48 sb!unix::*interrupt-pending*
49 *type-system-initialized*)
51 (special *before-gc-hooks* *after-gc-hooks*
53 *type-system-initialized*))
55 (defvar *cold-init-complete-p*)
57 ;;; counts of nested errors (with internal errors double-counted)
58 (defvar *maximum-error-depth*)
59 (defvar *current-error-depth*)
61 ;;;; miscellaneous utilities for working with with TOPLEVEL
63 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
64 ;;; by QUIT) is caught and any final processing and return codes are
65 ;;; handled appropriately.
66 (defmacro handling-end-of-the-world (&body body)
67 (let ((caught (gensym "CAUGHT")))
68 `(let ((,caught (catch '%end-of-the-world
69 (/show0 "inside CATCH '%END-OF-THE-WORLD")
71 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
72 (flush-standard-output-streams)
73 (/show0 "calling UNIX-EXIT")
74 (sb!unix:unix-exit ,caught))))
76 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
78 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out of
80 (defmacro infinite-error-protect (&rest forms)
81 `(unless (infinite-error-protector)
82 (let ((*current-error-depth* (1+ *current-error-depth*)))
85 ;;; a helper function for INFINITE-ERROR-PROTECT
86 (defun infinite-error-protector ()
87 (cond ((not *cold-init-complete-p*)
88 (%primitive print "Argh! error in cold init, halting")
89 (%primitive sb!c:halt))
90 ((or (not (boundp '*current-error-depth*))
91 (not (realp *current-error-depth*))
92 (not (boundp '*maximum-error-depth*))
93 (not (realp *maximum-error-depth*)))
94 (%primitive print "Argh! corrupted error depth, halting")
95 (%primitive sb!c:halt))
96 ((> *current-error-depth* *maximum-error-depth*)
97 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
101 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
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 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
131 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
135 ;;;; miscellaneous external functions
137 #!-mp ; The multi-processing version is defined in multi-proc.lisp.
140 "This function causes execution to be suspended for N seconds. N may
141 be any non-negative, non-complex number."
142 (when (or (not (realp n))
144 (error "Invalid argument to SLEEP: ~S.~%~
145 Must be a non-negative, non-complex number."
147 (multiple-value-bind (sec usec)
150 (multiple-value-bind (sec frac)
152 (values sec(truncate frac 1e-6))))
153 (sb!unix:unix-select 0 0 0 0 sec usec))
156 ;;;; SCRUB-CONTROL-STACK
158 (defconstant bytes-per-scrub-unit 2048)
160 (defun scrub-control-stack ()
162 "Zero the unused portion of the control stack so that old objects are not
163 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 (declare (optimize (speed 3) (safety 0))
171 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
173 #!-x86 ; machines where stack grows upwards (I guess) -- WHN 19990906
175 ((scrub (ptr offset count)
176 (declare (type system-area-pointer ptr)
177 (type (unsigned-byte 16) offset)
178 (type (unsigned-byte 20) count)
179 (values (unsigned-byte 20)))
180 (cond ((= offset bytes-per-scrub-unit)
181 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
183 (setf (sap-ref-32 ptr offset) 0)
184 (scrub ptr (+ offset sb!vm:word-bytes) count))))
185 (look (ptr offset count)
186 (declare (type system-area-pointer ptr)
187 (type (unsigned-byte 16) offset)
188 (type (unsigned-byte 20) count)
189 (values (unsigned-byte 20)))
190 (cond ((= offset bytes-per-scrub-unit)
192 ((zerop (sap-ref-32 ptr offset))
193 (look ptr (+ offset sb!vm:word-bytes) count))
195 (scrub ptr offset (+ count sb!vm:word-bytes))))))
196 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
197 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
198 (declare (type (unsigned-byte 32) csp))
199 (scrub (int-sap (- csp initial-offset))
200 (* (floor initial-offset sb!vm:word-bytes) sb!vm:word-bytes)
203 #!+x86 ;; (Stack grows downwards.)
205 ((scrub (ptr offset count)
206 (declare (type system-area-pointer ptr)
207 (type (unsigned-byte 16) offset)
208 (type (unsigned-byte 20) count)
209 (values (unsigned-byte 20)))
210 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:word-bytes)))))
211 (cond ((= offset bytes-per-scrub-unit)
212 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
214 (t ;; need to fix bug in %SET-STACK-REF
215 (setf (sap-ref-32 loc 0) 0)
216 (scrub ptr (+ offset sb!vm:word-bytes) count)))))
217 (look (ptr offset count)
218 (declare (type system-area-pointer ptr)
219 (type (unsigned-byte 16) offset)
220 (type (unsigned-byte 20) count)
221 (values (unsigned-byte 20)))
222 (let ((loc (int-sap (- (sap-int ptr) offset))))
223 (cond ((= offset bytes-per-scrub-unit)
225 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
226 (look ptr (+ offset sb!vm:word-bytes) count))
228 (scrub ptr offset (+ count sb!vm:word-bytes)))))))
229 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
230 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
231 (declare (type (unsigned-byte 32) csp))
232 (scrub (int-sap (+ csp initial-offset))
233 (* (floor initial-offset sb!vm:word-bytes) sb!vm:word-bytes)
236 ;;;; the default toplevel function
238 ;;; FIXME: Most stuff below here can probably be byte-compiled.
242 "a list of all the values returned by 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 EVAL")
246 (defvar ** nil #!+sb-doc "the previous value of *")
247 (defvar *** nil #!+sb-doc "the previous value of **")
248 (defvar + nil #!+sb-doc "the value of the most recent top-level READ")
249 (defvar ++ nil #!+sb-doc "the previous value of +")
250 (defvar +++ nil #!+sb-doc "the previous value of ++")
251 (defvar - nil #!+sb-doc "the form currently being evaluated")
252 (defvar *prompt* "* "
254 "The top-level prompt string. This also may be a function of no arguments
255 that returns a simple-string.")
257 (defun interactive-eval (form)
258 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
259 +++, ++, +, ///, //, /, and -."
261 (let ((results (multiple-value-list (eval form))))
272 ;; The bogon returned an unbound marker.
273 ;; FIXME: It would be safer to check every one of the values in RESULTS,
274 ;; instead of just the first one.
276 (cerror "Go on with * set to NIL."
277 "EVAL returned an unbound marker."))
280 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
281 ;;; output streams before proceeding.
282 (defun flush-standard-output-streams ()
283 (dolist (name '(*debug-io*
288 (finish-output (symbol-value name)))
291 ;;; the default system top-level function
292 (defun toplevel-init ()
294 (/show0 "entering TOPLEVEL-INIT")
296 (let ((sysinit nil) ; value of --sysinit option
297 (userinit nil) ; value of --userinit option
298 (reversed-evals nil) ; values of --eval options, in reverse order
299 (noprint nil) ; Has a --noprint option been seen?
300 (noprogrammer nil) ; Has a --noprogammer option been seen?
301 (options (rest *posix-argv*))) ; skipping program name
303 (/show0 "done with outer LET in TOPLEVEL-INIT")
305 ;; FIXME: There are lots of ways for errors to happen around here
306 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
307 ;; READ an --eval string). Make sure that they're handled
308 ;; reasonably. Also, perhaps all errors while parsing the command
309 ;; line should cause the system to QUIT, instead of trying to go
310 ;; into the Lisp debugger.
312 ;; Parse command line options.
313 (loop while options do
314 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
315 (let ((option (first options)))
316 (flet ((pop-option ()
319 (error "unexpected end of command line options"))))
320 (cond ((string= option "--sysinit")
323 (error "multiple --sysinit options")
324 (setf sysinit (pop-option))))
325 ((string= option "--userinit")
328 (error "multiple --userinit options")
329 (setf userinit (pop-option))))
330 ((string= option "--eval")
332 (let ((eval-as-string (pop-option)))
333 (with-input-from-string (eval-stream eval-as-string)
334 (let* ((eof-marker (cons :eof :eof))
335 (eval (read eval-stream nil eof-marker))
336 (eof (read eval-stream nil eof-marker)))
337 (cond ((eq eval eof-marker)
338 (error "unable to parse ~S"
340 ((not (eq eof eof-marker))
341 (error "more than one expression in ~S"
344 (push eval reversed-evals)))))))
345 ((string= option "--noprint")
348 ((string= option "--noprogrammer")
350 (setf noprogrammer t))
351 ((string= option "--end-toplevel-options")
355 ;; Anything we don't recognize as a toplevel
356 ;; option must be the start of user-level
357 ;; options.. except that if we encounter
358 ;; "--end-toplevel-options" after we gave up
359 ;; because we didn't recognize an option as a
360 ;; toplevel option, then the option we gave up on
361 ;; must have been an error. (E.g. in
362 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
363 ;; this test will let us detect that the string
364 ;; "--eval(b)" is an error.)
365 (if (find "--end-toplevel-options" options
367 (error "bad toplevel option: ~S" (first options))
369 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
371 ;; Excise all the options that we processed, so that only
372 ;; user-level options are left visible to user code.
373 (setf (rest *posix-argv*) options)
375 ;; Handle --noprogrammer option. We intentionally do this
376 ;; early so that it will affect the handling of initialization
377 ;; files and --eval options.
378 (/show0 "handling --noprogrammer option in TOPLEVEL-INIT")
380 (setf *debugger-hook* 'noprogrammer-debugger-hook-fun
381 *debug-io* *error-output*))
383 ;; FIXME: Verify that errors in init files and/or --eval operations
384 ;; lead to reasonable behavior.
386 ;; Handle initialization files.
387 (/show0 "handling initialization files in TOPLEVEL-INIT")
388 (flet (;; If any of POSSIBLE-INIT-FILE-NAMES names a real file,
389 ;; return its truename.
390 (probe-init-files (&rest possible-init-file-names)
391 (/show0 "entering PROBE-INIT-FILES")
394 (and (stringp x) (probe-file x)))
395 possible-init-file-names)
396 (/show0 "leaving PROBE-INIT-FILES"))))
397 (let* ((sbcl-home (posix-getenv "SBCL_HOME"))
398 (sysinit-truename (if sbcl-home
399 (probe-init-files sysinit
404 (probe-init-files sysinit
406 "/usr/local/etc/sbclrc")))
407 (user-home (or (posix-getenv "HOME")
408 (error "The HOME environment variable is unbound, ~
409 so user init file can't be found.")))
410 (userinit-truename (probe-init-files userinit
415 (/show0 "assigned SYSINIT-TRUENAME and USERINIT-TRUENAME")
418 ;; We wrap all the pre-REPL user/system customized startup code
421 ;; (Why not wrap everything, even the stuff above, in this
422 ;; restart? Errors above here are basically command line or
423 ;; Unix environment errors, e.g. a missing file or a typo on
424 ;; the Unix command line, and you don't need to get into Lisp
425 ;; to debug them, you should just start over and do it right
426 ;; at the Unix level. Errors below here are usually errors in
427 ;; user Lisp code, and it might be helpful to let the user
428 ;; reach the REPL in order to help figure out what's going on.)
430 (flet ((process-init-file (truename)
432 (unless (load truename)
433 (error "~S was not successfully loaded." truename))
434 (flush-standard-output-streams))))
435 (process-init-file sysinit-truename)
436 (process-init-file userinit-truename)
438 ;; Process --eval options.
439 (/show0 "handling --eval options in TOPLEVEL-INIT")
440 (dolist (eval (reverse reversed-evals))
441 (/show0 "handling one --eval option in TOPLEVEL-INIT")
443 (flush-standard-output-streams)))
445 :report "Continue anyway (skipping to toplevel read/eval/print loop)."
446 (values)) ; (no-op, just fall through)
448 :report "Quit SBCL (calling #'QUIT, killing the process)."
451 ;; one more time for good measure, in case we fell out of the
452 ;; RESTART-CASE above before one of the flushes in the ordinary
453 ;; flow of control had a chance to operate
454 (flush-standard-output-streams)
456 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
457 (toplevel-repl noprint))))
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 (eof-marker (cons :eof nil)))
468 (/show0 "at head of outer LOOP in TOPLEVEL-REPL")
469 ;; There should only be one TOPLEVEL restart, and it's here, so
470 ;; restarting at TOPLEVEL always bounces you all the way out here.
471 (with-simple-restart (toplevel
472 "Restart at toplevel READ/EVAL/PRINT loop.")
473 ;; We add a new ABORT restart for every debugger level, so
474 ;; restarting at ABORT in a nested debugger gets you out to the
475 ;; innermost enclosing debugger, and only when you're in the
476 ;; outermost, unnested debugger level does restarting at ABORT
477 ;; get you out to here.
478 (with-simple-restart (abort
479 "Reduce debugger level (leaving debugger).")
480 (catch 'top-level-catcher
481 (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
482 (/show0 "about to enter inner LOOP in TOPLEVEL-REPL")
483 (loop ; FIXME: Do we need this inner LOOP?
484 ;; FIXME: It seems bad to have GC behavior depend on scrubbing
485 ;; the control stack before each interactive command. Isn't
486 ;; there some way we can convince the GC to just ignore
487 ;; dead areas of the control stack, so that we don't need to
488 ;; rely on this half-measure?
489 (scrub-control-stack)
492 (princ (if (functionp *prompt*)
495 (flush-standard-output-streams))
496 (let ((form (read *standard-input* nil eof-marker)))
497 (if (eq form eof-marker)
500 (multiple-value-list (interactive-eval form))))
502 (dolist (result results)
504 (prin1 result)))))))))))))
506 (defun noprogrammer-debugger-hook-fun (condition old-debugger-hook)
507 (declare (ignore old-debugger-hook))
508 (flet ((failure-quit (&key recklessly-p)
509 (quit :unix-status 1 :recklessly-p recklessly-p)))
510 ;; This HANDLER-CASE is here mostly to stop output immediately
511 ;; (and fall through to QUIT) when there's an I/O error. Thus,
512 ;; when we're run under a shell script or something, we can die
513 ;; cleanly when the script dies (and our pipes are cut), instead
514 ;; of falling into ldb or something messy like that.
517 (format *error-output*
518 "~@<unhandled condition (of type ~S): ~2I~_~A~:>~2%"
521 ;; Flush *ERROR-OUTPUT* even before the BACKTRACE, so that
522 ;; even if we hit an error within BACKTRACE we'll at least
523 ;; have the CONDITION printed out before we die.
524 (finish-output *error-output*)
525 ;; (Where to truncate the BACKTRACE is of course arbitrary, but
526 ;; it seems as though we should at least truncate it somewhere.)
527 (sb!debug:backtrace 128 *error-output*)
528 (format *error-output*
529 "~%unhandled condition in --noprogrammer mode, quitting~%")
530 (finish-output *error-output*)
533 ;; We IGNORE-ERRORS here because even %PRIMITIVE PRINT can
534 ;; fail when our output streams are blown away, as e.g. when
535 ;; we're running under a Unix shell script and it dies somehow
536 ;; (e.g. because of a SIGINT). In that case, we might as well
537 ;; just give it up for a bad job, and stop trying to notify
538 ;; the user of anything.
540 ;; Actually, the only way I've run across to exercise the
541 ;; problem is to have more than one layer of shell script.
542 ;; I have a shell script which does
543 ;; time nice -10 sh make.sh "$1" 2>&1 | tee make.tmp
544 ;; and the problem occurs when I interrupt this with Ctrl-C
545 ;; under Linux 2.2.14-5.0 and GNU bash, version 1.14.7(1).
546 ;; I haven't figured out whether it's bash, time, tee, Linux, or
547 ;; what that is responsible, but that it's possible at all
548 ;; means that we should IGNORE-ERRORS here. -- WHN 2001-04-24
550 (%primitive print "Argh! error within --noprogrammer error handling"))
551 (failure-quit :recklessly-p t)))))
553 ;;; a convenient way to get into the assembly-level debugger
555 (%primitive sb!c:halt))