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
28 (defvar *current-catch-block*)
29 (defvar *current-unwind-protect-block*)
30 (defvar *free-interrupt-context-index*))
32 ;;; specials initialized by !COLD-INIT
34 ;;; FIXME: These could be converted to DEFVARs, and the stuff shared
35 ;;; in both #!+GENGC and #!-GENGC (actually everything in #!+GENGC)
36 ;;; could be made non-conditional.
39 (special *gc-inhibit* *already-maybe-gcing*
40 *need-to-collect-garbage* *gc-verbose*
42 *before-gc-hooks* *after-gc-hooks*
43 #!+x86 *pseudo-atomic-atomic*
44 #!+x86 *pseudo-atomic-interrupted*
45 sb!unix::*interrupts-enabled*
46 sb!unix::*interrupt-pending*
47 *type-system-initialized*)
49 (special *gc-verbose* *before-gc-hooks* *after-gc-hooks*
51 *type-system-initialized*))
53 (defvar *cold-init-complete-p*)
55 ;;; counts of nested errors (with internal errors double-counted)
56 (defvar *maximum-error-depth*)
57 (defvar *current-error-depth*)
59 ;;;; miscellaneous utilities for working with with TOPLEVEL
61 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
62 ;;; by QUIT) is caught and any final processing and return codes are
63 ;;; handled appropriately.
64 (defmacro handling-end-of-the-world (&body body)
65 (let ((caught (gensym "CAUGHT")))
66 `(let ((,caught (catch '%end-of-the-world
67 (/show0 "inside CATCH '%END-OF-THE-WORLD")
68 (restart-case (progn ,@body)
69 ;; KLUDGE: I'd like to name this restart QUIT,
70 ;; but then people would hate me, since in CMU
71 ;; CL, even though they have essentially the
72 ;; same QUIT function as SBCL, the "QUIT"
73 ;; command in the debugger means to return to
74 ;; the toplevel, not to actually call QUIT. Oh
75 ;; well. -- WHN 2000-11-01
79 "Terminate the current Lisp, ~
83 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
84 (flush-standard-output-streams)
85 (/show0 "calling UNIX-EXIT")
86 (sb!unix:unix-exit ,caught))))
88 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
90 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out of
92 (defmacro infinite-error-protect (&rest forms)
93 `(unless (infinite-error-protector)
94 (let ((*current-error-depth* (1+ *current-error-depth*)))
97 ;;; a helper function for INFINITE-ERROR-PROTECT
98 (defun infinite-error-protector ()
99 (cond ((not *cold-init-complete-p*)
100 (%primitive print "Argh! error in cold init, halting")
101 (%primitive sb!c:halt))
102 ((or (not (boundp '*current-error-depth*))
103 (not (realp *current-error-depth*))
104 (not (boundp '*maximum-error-depth*))
105 (not (realp *maximum-error-depth*)))
106 (%primitive print "Argh! corrupted error depth, halting")
107 (%primitive sb!c:halt))
108 ((> *current-error-depth* *maximum-error-depth*)
109 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
110 (error-error "Help! "
111 *current-error-depth*
113 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
118 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
119 ;;; one point (shown below), and SBCL cross-compiled it without
120 ;;; warning about FORMS being undefined. Check whether that problem
121 ;;; (missing warning) is repeatable in the final system and if so, fix
124 (defun infinite-error-protector ()
125 `(cond ((not *cold-init-complete-p*)
126 (%primitive print "Argh! error in cold init, halting")
127 (%primitive sb!c:halt))
128 ((or (not (boundp '*current-error-depth*))
129 (not (realp *current-error-depth*))
130 (not (boundp '*maximum-error-depth*))
131 (not (realp *maximum-error-depth*)))
132 (%primitive print "Argh! corrupted error depth, halting")
133 (%primitive sb!c:halt))
134 ((> *current-error-depth* *maximum-error-depth*)
135 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
136 (error-error "Help! "
137 *current-error-depth*
139 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
143 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
147 ;;;; miscellaneous external functions
149 #!-mp ; The multi-processing version is defined in multi-proc.lisp.
152 "This function causes execution to be suspended for N seconds. N may
153 be any non-negative, non-complex number."
154 (when (or (not (realp n))
156 (error "Invalid argument to SLEEP: ~S.~%~
157 Must be a non-negative, non-complex number."
159 (multiple-value-bind (sec usec)
162 (multiple-value-bind (sec frac)
164 (values sec(truncate frac 1e-6))))
165 (sb!unix:unix-select 0 0 0 0 sec usec))
168 ;;;; SCRUB-CONTROL-STACK
170 (defconstant bytes-per-scrub-unit 2048)
172 (defun scrub-control-stack ()
174 "Zero the unused portion of the control stack so that old objects are not
175 kept alive because of uninitialized stack variables."
176 ;; FIXME: Why do we need to do this instead of just letting GC read
177 ;; the stack pointer and avoid messing with the unused portion of
178 ;; the control stack? (Is this a multithreading thing where there's
179 ;; one control stack and stack pointer per thread, and it might not
180 ;; be easy to tell what a thread's stack pointer value is when
181 ;; looking in from another thread?)
182 (declare (optimize (speed 3) (safety 0))
183 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
185 #!-x86 ; machines where stack grows upwards (I guess) -- WHN 19990906
187 ((scrub (ptr offset count)
188 (declare (type system-area-pointer ptr)
189 (type (unsigned-byte 16) offset)
190 (type (unsigned-byte 20) count)
191 (values (unsigned-byte 20)))
192 (cond ((= offset bytes-per-scrub-unit)
193 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
195 (setf (sap-ref-32 ptr offset) 0)
196 (scrub ptr (+ offset sb!vm:word-bytes) count))))
197 (look (ptr offset count)
198 (declare (type system-area-pointer ptr)
199 (type (unsigned-byte 16) offset)
200 (type (unsigned-byte 20) count)
201 (values (unsigned-byte 20)))
202 (cond ((= offset bytes-per-scrub-unit)
204 ((zerop (sap-ref-32 ptr offset))
205 (look ptr (+ offset sb!vm:word-bytes) count))
207 (scrub ptr offset (+ count sb!vm:word-bytes))))))
208 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
209 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
210 (declare (type (unsigned-byte 32) csp))
211 (scrub (int-sap (- csp initial-offset))
212 (* (floor initial-offset sb!vm:word-bytes) sb!vm:word-bytes)
215 #!+x86 ;; (Stack grows downwards.)
217 ((scrub (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 sb!vm:word-bytes)))))
223 (cond ((= offset bytes-per-scrub-unit)
224 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
226 (t ;; need to fix bug in %SET-STACK-REF
227 (setf (sap-ref-32 loc 0) 0)
228 (scrub ptr (+ offset sb!vm:word-bytes) count)))))
229 (look (ptr offset count)
230 (declare (type system-area-pointer ptr)
231 (type (unsigned-byte 16) offset)
232 (type (unsigned-byte 20) count)
233 (values (unsigned-byte 20)))
234 (let ((loc (int-sap (- (sap-int ptr) offset))))
235 (cond ((= offset bytes-per-scrub-unit)
237 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
238 (look ptr (+ offset sb!vm:word-bytes) count))
240 (scrub ptr offset (+ count sb!vm:word-bytes)))))))
241 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
242 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
243 (declare (type (unsigned-byte 32) csp))
244 (scrub (int-sap (+ csp initial-offset))
245 (* (floor initial-offset sb!vm:word-bytes) sb!vm:word-bytes)
248 ;;;; the default toplevel function
252 "a list of all the values returned by the most recent top-level EVAL")
253 (defvar // nil #!+sb-doc "the previous value of /")
254 (defvar /// nil #!+sb-doc "the previous value of //")
255 (defvar * nil #!+sb-doc "the value of the most recent top-level EVAL")
256 (defvar ** nil #!+sb-doc "the previous value of *")
257 (defvar *** nil #!+sb-doc "the previous value of **")
258 (defvar + nil #!+sb-doc "the value of the most recent top-level READ")
259 (defvar ++ nil #!+sb-doc "the previous value of +")
260 (defvar +++ nil #!+sb-doc "the previous value of ++")
261 (defvar - nil #!+sb-doc "the form currently being evaluated")
262 (defvar *prompt* "* "
264 "The top-level prompt string. This also may be a function of no arguments
265 that returns a simple-string.")
267 (defun interactive-eval (form)
268 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
269 +++, ++, +, ///, //, /, and -."
271 (let ((results (multiple-value-list (eval form))))
282 ;; The bogon returned an unbound marker.
283 ;; FIXME: It would be safer to check every one of the values in RESULTS,
284 ;; instead of just the first one.
286 (cerror "Go on with * set to NIL."
287 "EVAL returned an unbound marker."))
290 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
291 ;;; output streams before proceeding.
292 (defun flush-standard-output-streams ()
293 (dolist (name '(*debug-io*
298 (finish-output (symbol-value name)))
301 ;;; the default system top-level function
302 (defun toplevel-init ()
304 (/show0 "entering TOPLEVEL-INIT")
306 (let ((sysinit nil) ; value of --sysinit option
307 (userinit nil) ; value of --userinit option
308 (evals nil) ; values of --eval options (in reverse order)
309 (noprint nil) ; Has a --noprint option been seen?
310 (noprogrammer nil) ; Has a --noprogammer option been seen?
311 (options (rest *posix-argv*))) ; skipping program name
313 (/show0 "done with outer LET in TOPLEVEL-INIT")
315 ;; FIXME: There are lots of ways for errors to happen around here (e.g. bad
316 ;; command line syntax, or READ-ERROR while trying to READ an --eval
317 ;; string). Make sure that they're handled reasonably.
319 ;; Parse command line options.
320 (loop while options do
321 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
322 (let ((option (first options)))
323 (flet ((pop-option ()
326 (error "unexpected end of command line options"))))
327 (cond ((string= option "--sysinit")
330 (error "multiple --sysinit options")
331 (setf sysinit (pop-option))))
332 ((string= option "--userinit")
335 (error "multiple --userinit options")
336 (setf userinit (pop-option))))
337 ((string= option "--eval")
339 (let ((eval-as-string (pop-option)))
340 (with-input-from-string (eval-stream eval-as-string)
341 (let* ((eof-marker (cons :eof :eof))
342 (eval (read eval-stream nil eof-marker))
343 (eof (read eval-stream nil eof-marker)))
344 (cond ((eq eval eof-marker)
345 (error "unable to parse ~S"
347 ((not (eq eof eof-marker))
348 (error "more than one expression in ~S"
351 (push eval evals)))))))
352 ((string= option "--noprint")
355 ((string= option "--noprogrammer")
357 (setf noprogrammer t))
358 ((string= option "--end-toplevel-options")
362 ;; Anything we don't recognize as a toplevel
363 ;; option must be the start of user-level
364 ;; options.. except that if we encounter
365 ;; "--end-toplevel-options" after we gave up
366 ;; because we didn't recognize an option as a
367 ;; toplevel option, then the option we gave up on
368 ;; must have been an error. (E.g. in
369 ;; sbcl --eval '(a)' --evl '(b)' --end-toplevel-options
370 ;; this test will let us detect that "--evl" is
372 (if (find "--end-toplevel-options" options
374 (error "bad toplevel option: ~S" (first options))
376 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
378 ;; Excise all the options that we processed, so that only user-level
379 ;; options are left visible to user code.
380 (setf (rest *posix-argv*) options)
382 ;; FIXME: Verify that errors in init files and/or --eval operations
383 ;; lead to reasonable behavior.
385 ;; Handle initialization files.
386 (/show0 "handling initialization files in TOPLEVEL-INIT")
387 (flet (;; If any of POSSIBLE-INIT-FILE-NAMES names a real file,
388 ;; return its truename.
389 (probe-init-files (&rest possible-init-file-names)
390 (/show0 "entering PROBE-INIT-FILES")
393 (and (stringp x) (probe-file x)))
394 possible-init-file-names)
395 (/show0 "leaving PROBE-INIT-FILES"))))
396 (let* ((sbcl-home (posix-getenv "SBCL_HOME"))
397 (sysinit-truename (if sbcl-home
398 (probe-init-files sysinit
403 (probe-init-files sysinit
405 "/usr/local/etc/sbclrc")))
406 (user-home (or (posix-getenv "HOME")
407 (error "The HOME environment variable is unbound, ~
408 so user init file can't be found.")))
409 (userinit-truename (probe-init-files userinit
414 (/show0 "assigned SYSINIT-TRUENAME and USERINIT-TRUENAME")
415 (when sysinit-truename
416 (unless (load sysinit-truename)
417 (error "~S was not successfully loaded." sysinit-truename))
418 (flush-standard-output-streams))
419 (/show0 "loaded SYSINIT-TRUENAME")
420 (when userinit-truename
421 (unless (load userinit-truename)
422 (error "~S was not successfully loaded." userinit-truename))
423 (flush-standard-output-streams))
424 (/show0 "loaded USERINIT-TRUENAME"))
426 ;; Handle --eval options.
427 (/show0 "handling --eval options in TOPLEVEL-INIT")
428 (dolist (eval (reverse evals))
429 (/show0 "handling one --eval option in TOPLEVEL-INIT")
431 (flush-standard-output-streams))
433 ;; Handle stream binding controlled by --noprogrammer option.
435 ;; FIXME: When we do actually implement this, shouldn't it go
436 ;; earlier in the sequence, so that its stream bindings will
437 ;; affect the behavior of init files and --eval options?
438 (/show0 "handling --noprogrammer option in TOPLEVEL-INIT")
440 (warn "stub: --noprogrammer option unimplemented")) ; FIXME
442 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
443 (toplevel-repl noprint))))
445 ;;; read-eval-print loop for the default system toplevel
446 (defun toplevel-repl (noprint)
447 (/show0 "entering TOPLEVEL-REPL")
448 (let ((* nil) (** nil) (*** nil)
450 (+ nil) (++ nil) (+++ nil)
451 (/// nil) (// nil) (/ nil)
452 (eof-marker (cons :eof nil)))
454 (/show0 "at head of outer LOOP in TOPLEVEL-REPL")
455 ;; There should only be one TOPLEVEL restart, and it's here, so
456 ;; restarting at TOPLEVEL always bounces you all the way out here.
457 (with-simple-restart (toplevel
458 "Restart at toplevel READ/EVAL/PRINT loop.")
459 ;; We add a new ABORT restart for every debugger level, so
460 ;; restarting at ABORT in a nested debugger gets you out to the
461 ;; innermost enclosing debugger, and only when you're in the
462 ;; outermost, unnested debugger level does restarting at ABORT
463 ;; get you out to here.
464 (with-simple-restart (abort
465 "Reduce debugger level (leaving debugger).")
466 (catch 'top-level-catcher
467 (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
468 (/show0 "about to enter inner LOOP in TOPLEVEL-REPL")
469 (loop ; FIXME: Do we need this inner LOOP?
470 ;; FIXME: It seems bad to have GC behavior depend on scrubbing
471 ;; the control stack before each interactive command. Isn't
472 ;; there some way we can convince the GC to just ignore
473 ;; dead areas of the control stack, so that we don't need to
474 ;; rely on this half-measure?
475 (scrub-control-stack)
478 (princ (if (functionp *prompt*)
481 (flush-standard-output-streams))
482 (let ((form (read *standard-input* nil eof-marker)))
483 (if (eq form eof-marker)
486 (multiple-value-list (interactive-eval form))))
488 (dolist (result results)
490 (prin1 result)))))))))))))
492 ;;; a convenient way to get into the assembly-level debugger
494 (%primitive sb!c:halt))