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")
69 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
70 (flush-standard-output-streams)
71 (/show0 "calling UNIX-EXIT")
72 (sb!unix:unix-exit ,caught))))
74 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
76 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out of
78 (defmacro infinite-error-protect (&rest forms)
79 `(unless (infinite-error-protector)
80 (let ((*current-error-depth* (1+ *current-error-depth*)))
83 ;;; a helper function for INFINITE-ERROR-PROTECT
84 (defun infinite-error-protector ()
85 (cond ((not *cold-init-complete-p*)
86 (%primitive print "Argh! error in cold init, halting")
87 (%primitive sb!c:halt))
88 ((or (not (boundp '*current-error-depth*))
89 (not (realp *current-error-depth*))
90 (not (boundp '*maximum-error-depth*))
91 (not (realp *maximum-error-depth*)))
92 (%primitive print "Argh! corrupted error depth, halting")
93 (%primitive sb!c:halt))
94 ((> *current-error-depth* *maximum-error-depth*)
95 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
99 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
104 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
105 ;;; one point (shown below), and SBCL cross-compiled it without
106 ;;; warning about FORMS being undefined. Check whether that problem
107 ;;; (missing warning) is repeatable in the final system and if so, fix
110 (defun infinite-error-protector ()
111 `(cond ((not *cold-init-complete-p*)
112 (%primitive print "Argh! error in cold init, halting")
113 (%primitive sb!c:halt))
114 ((or (not (boundp '*current-error-depth*))
115 (not (realp *current-error-depth*))
116 (not (boundp '*maximum-error-depth*))
117 (not (realp *maximum-error-depth*)))
118 (%primitive print "Argh! corrupted error depth, halting")
119 (%primitive sb!c:halt))
120 ((> *current-error-depth* *maximum-error-depth*)
121 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
122 (error-error "Help! "
123 *current-error-depth*
125 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
129 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
133 ;;;; miscellaneous external functions
135 #!-mp ; The multi-processing version is defined in multi-proc.lisp.
138 "This function causes execution to be suspended for N seconds. N may
139 be any non-negative, non-complex number."
140 (when (or (not (realp n))
142 (error "Invalid argument to SLEEP: ~S.~%~
143 Must be a non-negative, non-complex number."
145 (multiple-value-bind (sec usec)
148 (multiple-value-bind (sec frac)
150 (values sec(truncate frac 1e-6))))
151 (sb!unix:unix-select 0 0 0 0 sec usec))
154 ;;;; SCRUB-CONTROL-STACK
156 (defconstant bytes-per-scrub-unit 2048)
158 (defun scrub-control-stack ()
160 "Zero the unused portion of the control stack so that old objects are not
161 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 (declare (optimize (speed 3) (safety 0))
169 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
171 #!-x86 ; machines where stack grows upwards (I guess) -- WHN 19990906
173 ((scrub (ptr offset count)
174 (declare (type system-area-pointer ptr)
175 (type (unsigned-byte 16) offset)
176 (type (unsigned-byte 20) count)
177 (values (unsigned-byte 20)))
178 (cond ((= offset bytes-per-scrub-unit)
179 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
181 (setf (sap-ref-32 ptr offset) 0)
182 (scrub ptr (+ offset sb!vm:word-bytes) count))))
183 (look (ptr offset count)
184 (declare (type system-area-pointer ptr)
185 (type (unsigned-byte 16) offset)
186 (type (unsigned-byte 20) count)
187 (values (unsigned-byte 20)))
188 (cond ((= offset bytes-per-scrub-unit)
190 ((zerop (sap-ref-32 ptr offset))
191 (look ptr (+ offset sb!vm:word-bytes) count))
193 (scrub ptr offset (+ count sb!vm:word-bytes))))))
194 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
195 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
196 (declare (type (unsigned-byte 32) csp))
197 (scrub (int-sap (- csp initial-offset))
198 (* (floor initial-offset sb!vm:word-bytes) sb!vm:word-bytes)
201 #!+x86 ;; (Stack grows downwards.)
203 ((scrub (ptr offset count)
204 (declare (type system-area-pointer ptr)
205 (type (unsigned-byte 16) offset)
206 (type (unsigned-byte 20) count)
207 (values (unsigned-byte 20)))
208 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:word-bytes)))))
209 (cond ((= offset bytes-per-scrub-unit)
210 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
212 (t ;; need to fix bug in %SET-STACK-REF
213 (setf (sap-ref-32 loc 0) 0)
214 (scrub ptr (+ offset sb!vm:word-bytes) count)))))
215 (look (ptr offset count)
216 (declare (type system-area-pointer ptr)
217 (type (unsigned-byte 16) offset)
218 (type (unsigned-byte 20) count)
219 (values (unsigned-byte 20)))
220 (let ((loc (int-sap (- (sap-int ptr) offset))))
221 (cond ((= offset bytes-per-scrub-unit)
223 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
224 (look ptr (+ offset sb!vm:word-bytes) count))
226 (scrub ptr offset (+ count sb!vm:word-bytes)))))))
227 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
228 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
229 (declare (type (unsigned-byte 32) csp))
230 (scrub (int-sap (+ csp initial-offset))
231 (* (floor initial-offset sb!vm:word-bytes) sb!vm:word-bytes)
234 ;;;; the default toplevel function
238 "a list of all the values returned by the most recent top-level EVAL")
239 (defvar // nil #!+sb-doc "the previous value of /")
240 (defvar /// nil #!+sb-doc "the previous value of //")
241 (defvar * nil #!+sb-doc "the value of 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 READ")
245 (defvar ++ nil #!+sb-doc "the previous value of +")
246 (defvar +++ nil #!+sb-doc "the previous value of ++")
247 (defvar - nil #!+sb-doc "the form currently being evaluated")
248 (defvar *prompt* "* "
250 "The top-level prompt string. This also may be a function of no arguments
251 that returns a simple-string.")
253 (defun interactive-eval (form)
254 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
255 +++, ++, +, ///, //, /, and -."
257 (let ((results (multiple-value-list (eval form))))
268 ;; The bogon returned an unbound marker.
269 ;; FIXME: It would be safer to check every one of the values in RESULTS,
270 ;; instead of just the first one.
272 (cerror "Go on with * set to NIL."
273 "EVAL returned an unbound marker."))
276 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
277 ;;; output streams before proceeding.
278 (defun flush-standard-output-streams ()
279 (dolist (name '(*debug-io*
284 (finish-output (symbol-value name)))
287 ;;; the default system top-level function
288 (defun toplevel-init ()
290 (/show0 "entering TOPLEVEL-INIT")
292 (let ((sysinit nil) ; value of --sysinit option
293 (userinit nil) ; value of --userinit option
294 (evals nil) ; values of --eval options (in reverse order)
295 (noprint nil) ; Has a --noprint option been seen?
296 (noprogrammer nil) ; Has a --noprogammer 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 (e.g. bad
302 ;; command line syntax, or READ-ERROR while trying to READ an --eval
303 ;; string). Make sure that they're handled reasonably.
305 ;; Parse command line options.
306 (loop while options do
307 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
308 (let ((option (first options)))
309 (flet ((pop-option ()
312 (error "unexpected end of command line options"))))
313 (cond ((string= option "--sysinit")
316 (error "multiple --sysinit options")
317 (setf sysinit (pop-option))))
318 ((string= option "--userinit")
321 (error "multiple --userinit options")
322 (setf userinit (pop-option))))
323 ((string= option "--eval")
325 (let ((eval-as-string (pop-option)))
326 (with-input-from-string (eval-stream eval-as-string)
327 (let* ((eof-marker (cons :eof :eof))
328 (eval (read eval-stream nil eof-marker))
329 (eof (read eval-stream nil eof-marker)))
330 (cond ((eq eval eof-marker)
331 (error "unable to parse ~S"
333 ((not (eq eof eof-marker))
334 (error "more than one expression in ~S"
337 (push eval evals)))))))
338 ((string= option "--noprint")
341 ((string= option "--noprogrammer")
343 (setf noprogrammer t))
344 ((string= option "--end-toplevel-options")
348 ;; Anything we don't recognize as a toplevel
349 ;; option must be the start of user-level
350 ;; options.. except that if we encounter
351 ;; "--end-toplevel-options" after we gave up
352 ;; because we didn't recognize an option as a
353 ;; toplevel option, then the option we gave up on
354 ;; must have been an error. (E.g. in
355 ;; sbcl --eval '(a)' --evl '(b)' --end-toplevel-options
356 ;; this test will let us detect that "--evl" is
358 (if (find "--end-toplevel-options" options
360 (error "bad toplevel option: ~S" (first options))
362 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
364 ;; Excise all the options that we processed, so that only user-level
365 ;; options are left visible to user code.
366 (setf (rest *posix-argv*) options)
368 ;; FIXME: Verify that errors in init files and/or --eval operations
369 ;; lead to reasonable behavior.
371 ;; Handle initialization files.
372 (/show0 "handling initialization files in TOPLEVEL-INIT")
373 (flet (;; If any of POSSIBLE-INIT-FILE-NAMES names a real file,
374 ;; return its truename.
375 (probe-init-files (&rest possible-init-file-names)
376 (/show0 "entering PROBE-INIT-FILES")
379 (and (stringp x) (probe-file x)))
380 possible-init-file-names)
381 (/show0 "leaving PROBE-INIT-FILES"))))
382 (let* ((sbcl-home (posix-getenv "SBCL_HOME"))
383 (sysinit-truename (if sbcl-home
384 (probe-init-files sysinit
389 (probe-init-files sysinit
391 "/usr/local/etc/sbclrc")))
392 (user-home (or (posix-getenv "HOME")
393 (error "The HOME environment variable is unbound, ~
394 so user init file can't be found.")))
395 (userinit-truename (probe-init-files userinit
400 (/show0 "assigned SYSINIT-TRUENAME and USERINIT-TRUENAME")
401 (when sysinit-truename
402 (unless (load sysinit-truename)
403 (error "~S was not successfully loaded." sysinit-truename))
404 (flush-standard-output-streams))
405 (/show0 "loaded SYSINIT-TRUENAME")
406 (when userinit-truename
407 (unless (load userinit-truename)
408 (error "~S was not successfully loaded." userinit-truename))
409 (flush-standard-output-streams))
410 (/show0 "loaded USERINIT-TRUENAME"))
412 ;; Handle --eval options.
413 (/show0 "handling --eval options in TOPLEVEL-INIT")
414 (dolist (eval (reverse evals))
415 (/show0 "handling one --eval option in TOPLEVEL-INIT")
417 (flush-standard-output-streams))
419 ;; Handle stream binding controlled by --noprogrammer option.
421 ;; FIXME: When we do actually implement this, shouldn't it go
422 ;; earlier in the sequence, so that its stream bindings will
423 ;; affect the behavior of init files and --eval options?
424 (/show0 "handling --noprogrammer option in TOPLEVEL-INIT")
426 (warn "stub: --noprogrammer option unimplemented")) ; FIXME
428 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
429 (toplevel-repl noprint))))
431 ;;; read-eval-print loop for the default system toplevel
432 (defun toplevel-repl (noprint)
433 (/show0 "entering TOPLEVEL-REPL")
434 (let ((* nil) (** nil) (*** nil)
436 (+ nil) (++ nil) (+++ nil)
437 (/// nil) (// nil) (/ nil)
438 (eof-marker (cons :eof nil)))
440 (/show0 "at head of outer LOOP in TOPLEVEL-REPL")
441 ;; There should only be one TOPLEVEL restart, and it's here, so
442 ;; restarting at TOPLEVEL always bounces you all the way out here.
443 (with-simple-restart (toplevel
444 "Restart at toplevel READ/EVAL/PRINT loop.")
445 ;; We add a new ABORT restart for every debugger level, so
446 ;; restarting at ABORT in a nested debugger gets you out to the
447 ;; innermost enclosing debugger, and only when you're in the
448 ;; outermost, unnested debugger level does restarting at ABORT
449 ;; get you out to here.
450 (with-simple-restart (abort
451 "Reduce debugger level (leaving debugger).")
452 (catch 'top-level-catcher
453 (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
454 (/show0 "about to enter inner LOOP in TOPLEVEL-REPL")
455 (loop ; FIXME: Do we need this inner LOOP?
456 ;; FIXME: It seems bad to have GC behavior depend on scrubbing
457 ;; the control stack before each interactive command. Isn't
458 ;; there some way we can convince the GC to just ignore
459 ;; dead areas of the control stack, so that we don't need to
460 ;; rely on this half-measure?
461 (scrub-control-stack)
464 (princ (if (functionp *prompt*)
467 (flush-standard-output-streams))
468 (let ((form (read *standard-input* nil eof-marker)))
469 (if (eq form eof-marker)
472 (multiple-value-list (interactive-eval form))))
474 (dolist (result results)
476 (prin1 result)))))))))))))
478 ;;; a convenient way to get into the assembly-level debugger
480 (%primitive sb!c:halt))