3 Bugs can be reported on the help mailing list
4 sbcl-help@lists.sourceforge.net
5 or on the development mailing list
6 sbcl-devel@lists.sourceforge.net
8 Please include enough information in a bug report that someone reading
9 it can reproduce the problem, i.e. don't write
10 Subject: apparent bug in PRINT-OBJECT (or *PRINT-LENGTH*?)
11 PRINT-OBJECT doesn't seem to work with *PRINT-LENGTH*. Is this a bug?
13 Subject: apparent bug in PRINT-OBJECT (or *PRINT-LENGTH*?)
14 In sbcl-1.2.3 running under OpenBSD 4.5 on my Alpha box, when
15 I compile and load the file
16 (DEFSTRUCT (FOO (:PRINT-OBJECT (LAMBDA (X Y)
17 (LET ((*PRINT-LENGTH* 4))
20 then at the command line type
22 the program loops endlessly instead of printing the object.
27 There is also some information on bugs in the manual page and
28 in the TODO file. Eventually more such information may move here.
30 The gaps in the number sequence belong to old bug descriptions which
31 have gone away (typically because they were fixed, but sometimes for
32 other reasons, e.g. because they were moved elsewhere).
35 KNOWN BUGS OF NO SPECIAL CLASS:
38 DEFSTRUCT almost certainly should overwrite the old LAYOUT information
39 instead of just punting when a contradictory structure definition
40 is loaded. As it is, if you redefine DEFSTRUCTs in a way which
41 changes their layout, you probably have to rebuild your entire
42 program, even if you know or guess enough about the internals of
43 SBCL to wager that this (undefined in ANSI) operation would be safe.
45 3: "type checking of structure slots"
47 ANSI specifies that a type mismatch in a structure slot
48 initialization value should not cause a warning.
50 This one might not be fixed for a while because while we're big
51 believers in ANSI compatibility and all, (1) there's no obvious
52 simple way to do it (short of disabling all warnings for type
53 mismatches everywhere), and (2) there's a good portable
54 workaround, and (3) by their own reasoning, it looks as though
55 ANSI may have gotten it wrong. ANSI justifies this specification
57 The restriction against issuing a warning for type mismatches
58 between a slot-initform and the corresponding slot's :TYPE
59 option is necessary because a slot-initform must be specified
60 in order to specify slot options; in some cases, no suitable
62 However, in SBCL (as in CMU CL or, for that matter, any compiler
63 which really understands Common Lisp types) a suitable default
64 does exist, in all cases, because the compiler understands the
65 concept of functions which never return (i.e. has return type NIL).
66 Thus, as a portable workaround, you can use a call to some
67 known-never-to-return function as the default. E.g.
69 (BAR (ERROR "missing :BAR argument")
70 :TYPE SOME-TYPE-TOO-HAIRY-TO-CONSTRUCT-AN-INSTANCE-OF))
72 (DECLAIM (FTYPE (FUNCTION () NIL) MISSING-ARG))
73 (DEFUN REQUIRED-ARG () ; workaround for SBCL non-ANSI slot init typing
74 (ERROR "missing required argument"))
76 (BAR (REQUIRED-ARG) :TYPE TRICKY-TYPE-OF-SOME-SORT)
77 (BLETCH (REQUIRED-ARG) :TYPE TRICKY-TYPE-OF-SOME-SORT)
78 (N-REFS-SO-FAR 0 :TYPE (INTEGER 0)))
79 Such code should compile without complaint and work correctly either
80 on SBCL or on any other completely compliant Common Lisp system.
82 b: &AUX argument in a boa-constructor without a default value means
83 "do not initilize this slot" and does not cause type error. But
84 an error may be signalled at read time and it would be good if
90 The "compiling top-level form:" output ought to be condensed.
91 Perhaps any number of such consecutive lines ought to turn into a
92 single "compiling top-level forms:" line.
95 It would be nice if the
97 (during macroexpansion)
98 said what macroexpansion was at fault, e.g.
100 (during macroexpansion of IN-PACKAGE,
101 during macroexpansion of DEFFOO)
104 (I *think* this is a bug. It certainly seems like strange behavior. But
105 the ANSI spec is scary, dark, and deep.. -- WHN)
106 (FORMAT NIL "~,1G" 1.4) => "1. "
107 (FORMAT NIL "~3,1G" 1.4) => "1. "
110 Sometimes (SB-EXT:QUIT) fails with
111 Argh! maximum interrupt nesting depth (4096) exceeded, exiting
112 Process inferior-lisp exited abnormally with code 1
113 I haven't noticed a repeatable case of this yet.
116 The printer doesn't report closures very well. This is true in
120 #<Closure Over Function "DEFUN STRUCTURE-SLOT-ACCESSOR" {134D1A1}>
121 It would be nice to make closures have a settable name slot,
122 and make things like DEFSTRUCT and FLET, which create closures,
123 set helpful values into this slot.
126 And as long as we're wishing, it would be awfully nice if INSPECT could
127 also report on closures, telling about the values of the bound variables.
130 The compiler assumes that any time a function of declared FTYPE
131 doesn't signal an error, its arguments were of the declared type.
132 E.g. compiling and loading
133 (DECLAIM (OPTIMIZE (SAFETY 3)))
134 (DEFUN FACTORIAL (X) (GAMMA (1+ X)))
136 (DECLAIM (FTYPE (FUNCTION (UNSIGNED-BYTE)) FACTORIAL))
138 (COND ((> (FACTORIAL X) 1.0E6)
139 (FORMAT T "too big~%"))
141 (FORMAT T "exactly ~S~%" (FACTORIAL X)))
143 (FORMAT T "approximately ~S~%" (FACTORIAL X)))))
146 will cause the INTEGERP case to be selected, giving bogus output a la
148 This violates the "declarations are assertions" principle.
149 According to the ANSI spec, in the section "System Class FUNCTION",
150 this is a case of "lying to the compiler", but the lying is done
151 by the code which calls FACTORIAL with non-UNSIGNED-BYTE arguments,
152 not by the unexpectedly general definition of FACTORIAL. In any case,
153 "declarations are assertions" means that lying to the compiler should
154 cause an error to be signalled, and should not cause a bogus
155 result to be returned. Thus, the compiler should not assume
156 that arbitrary functions check their argument types. (It might
157 make sense to add another flag (CHECKED?) to DEFKNOWN to
158 identify functions which *do* check their argument types.)
159 (Also, verify that the compiler handles declared function
160 return types as assertions.)
163 The definitions of SIGCONTEXT-FLOAT-REGISTER and
164 %SET-SIGCONTEXT-FLOAT-REGISTER in x86-vm.lisp say they're not
165 supported on FreeBSD because the floating point state is not saved,
166 but at least as of FreeBSD 4.0, the floating point state *is* saved,
167 so they could be supported after all. Very likely
168 SIGCONTEXT-FLOATING-POINT-MODES could now be supported, too.
171 a slew of floating-point-related errors reported by Peter Van Eynde
173 b: SBCL's value for LEAST-POSITIVE-SHORT-FLOAT on the x86 is
174 bogus, and should probably be 1.4012985e-45. In SBCL,
175 (/ LEAST-POSITIVE-SHORT-FLOAT 2) returns a number smaller
176 than LEAST-POSITIVE-SHORT-FLOAT. Similar problems
177 exist for LEAST-NEGATIVE-SHORT-FLOAT, LEAST-POSITIVE-LONG-FLOAT,
178 and LEAST-NEGATIVE-LONG-FLOAT.
179 c: Many expressions generate floating infinity on x86/Linux:
184 PVE's regression tests want them to raise errors. sbcl-0.7.0.5
185 on x86/Linux generates the infinities instead. That might or
186 might not be conforming behavior, but it's also inconsistent,
187 which is almost certainly wrong. (Inconsistency: (/ 1 0.0)
188 should give the same result as (/ 1.0 0.0), but instead (/ 1 0.0)
189 generates SINGLE-FLOAT-POSITIVE-INFINITY and (/ 1.0 0.0)
191 d: (in section12.erg) various forms a la
192 (FLOAT 1 DOUBLE-FLOAT-EPSILON)
193 don't give the right behavior.
196 type safety errors reported by Peter Van Eynde July 25, 2000:
197 k: READ-BYTE is supposed to signal TYPE-ERROR when its argument is
198 not a binary input stream, but instead cheerfully reads from
199 character streams, e.g. (MAKE-STRING-INPUT-STREAM "abc").
202 The debugger LIST-LOCATIONS command doesn't work properly.
203 (How should it work properly?)
206 Compiling and loading
207 (DEFUN FAIL (X) (THROW 'FAIL-TAG X))
209 then requesting a BACKTRACE at the debugger prompt gives no information
210 about where in the user program the problem occurred.
213 Using the pretty-printer from the command prompt gives funny
214 results, apparently because the pretty-printer doesn't know
215 about user's command input, including the user's carriage return
216 that the user, and therefore the pretty-printer thinks that
217 the new output block should start indented 2 or more characters
218 rightward of the correct location.
221 As reported by Winton Davies on a CMU CL mailing list 2000-01-10,
222 and reported for SBCL by Martin Atzmueller 2000-10-20: (TRACE GETHASH)
223 crashes SBCL. In general tracing anything which is used in the
224 implementation of TRACE is likely to have the same problem.
227 ANSI says in one place that type declarations can be abbreviated even
228 when the type name is not a symbol, e.g.
229 (DECLAIM ((VECTOR T) *FOOVECTOR*))
230 SBCL doesn't support this. But ANSI says in another place that this
231 isn't allowed. So it's not clear this is a bug after all. (See the
232 e-mail on cmucl-help@cons.org on 2001-01-16 and 2001-01-17 from WHN
236 as pointed out by Dan Barlow on sbcl-devel 2000-07-02:
237 The PICK-TEMPORARY-FILE-NAME utility used by LOAD-FOREIGN uses
238 an easily guessable temporary filename in a way which might open
239 applications using LOAD-FOREIGN to hijacking by malicious users
240 on the same machine. Incantations for doing this safely are
241 floating around the net in various "how to write secure programs
242 despite Unix" documents, and it would be good to (1) fix this in
243 LOAD-FOREIGN, and (2) hunt for any other code which uses temporary
244 files and make it share the same new safe logic.
246 (partially alleviated in sbcl-0.7.9.32 by a fix by Matthew Danish to
247 make the temporary filename less easily guessable)
250 RANDOM-INTEGER-EXTRA-BITS=10 may not be large enough for the RANDOM
251 RNG to be high quality near RANDOM-FIXNUM-MAX; it looks as though
252 the mean of the distribution can be systematically O(0.1%) wrong.
253 Just increasing R-I-E-B is probably not a good solution, since
254 it would decrease efficiency more than is probably necessary. Perhaps
255 using some sort of accept/reject method would be better.
258 Internally the compiler sometimes evaluates
259 (sb-kernel:type/= (specifier-type '*) (specifier-type t))
260 (I stumbled across this when I added an
261 (assert (not (eq type1 *wild-type*)))
262 in the NAMED :SIMPLE-= type method.) '* isn't really a type, and
263 in a type context should probably be translated to T, and so it's
264 probably wrong to ask whether it's equal to the T type and then (using
265 the EQ type comparison in the NAMED :SIMPLE-= type method) return NIL.
266 (I haven't tried to investigate this bug enough to guess whether
267 there might be any user-level symptoms.)
269 In fact, the type system is likely to depend on this inequality not
270 holding... * is not equivalent to T in many cases, such as
271 (VECTOR *) /= (VECTOR T).
274 The facility for dumping a running Lisp image to disk gets confused
275 when run without the PURIFY option, and creates an unnecessarily large
276 core file (apparently representing memory usage up to the previous
277 high-water mark). Moreover, when the file is loaded, it confuses the
278 GC, so that thereafter memory usage can never be reduced below that
282 In sbcl-0.6.11.41 (and in all earlier SBCL, and in CMU
283 CL), out-of-line structure slot setters are horribly inefficient
284 whenever the type of the slot is declared, because out-of-line
285 structure slot setters are implemented as closures to save space,
286 so the compiler doesn't compile the type test into code, but
287 instead just saves the type in a lexical closure and interprets it
289 To exercise the problem, compile and load
290 (cl:in-package :cl-user)
292 (bar (error "missing") :type bar))
295 (loop (setf (foo-bar *foo*) x)))
297 (defvar *bar* (make-bar))
298 (defvar *foo* (make-foo :bar *bar*))
299 (defvar *setf-foo-bar* #'(setf foo-bar))
301 (loop (funcall *setf-foo-bar* x *foo*)))
302 then run (WASTREL1 *BAR*) or (WASTREL2 *BAR*), hit Ctrl-C, and
303 use BACKTRACE, to see it's spending all essentially all its time
304 in %TYPEP and VALUES-SPECIFIER-TYPE and so forth.
305 One possible solution would be simply to give up on
306 representing structure slot accessors as functions, and represent
307 them as macroexpansions instead. This can be inconvenient for users,
308 but it's not clear that it's worse than trying to help by expanding
309 into a horribly inefficient implementation.
310 As a workaround for the problem, #'(SETF FOO) expressions
311 can be replaced with (EFFICIENT-SETF-FUNCTION FOO), where
312 (defmacro efficient-setf-function (place-function-name)
313 (or #+sbcl (and (sb-int:info :function :accessor-for place-function-name)
314 ;; a workaround for the problem, encouraging the
315 ;; inline expansion of the structure accessor, so
316 ;; that the compiler can optimize its type test
317 (let ((new-value (gensym "NEW-VALUE-"))
318 (structure-value (gensym "STRUCTURE-VALUE-")))
319 `(lambda (,new-value ,structure-value)
320 (setf (,place-function-name ,structure-value)
322 ;; no problem, can just use the ordinary expansion
323 `(function (setf ,place-function-name))))
326 There's apparently a bug in CEILING optimization which caused
327 Douglas Crosher to patch the CMU CL version. Martin Atzmueller
328 applied the patches to SBCL and they didn't seem to cause problems
329 (as reported sbcl-devel 2001-05-04). However, since the patches
330 modify nontrivial code which was apparently written incorrectly
331 the first time around, until regression tests are written I'm not
332 comfortable merging the patches in the CVS version of SBCL.
335 (TIME (ROOM T)) reports more than 200 Mbytes consed even for
336 a clean, just-started SBCL system. And it seems to be right:
337 (ROOM T) can bring a small computer to its knees for a *long*
338 time trying to GC afterwards. Surely there's some more economical
339 way to implement (ROOM T).
342 When the compiler inline expands functions, it may be that different
343 kinds of return values are generated from different code branches.
344 E.g. an inline expansion of POSITION generates integer results
345 from one branch, and NIL results from another. When that inline
346 expansion is used in a context where only one of those results
349 (aref *a1* (position x *a2*)))
350 and the compiler can't prove that the unacceptable branch is
351 never taken, then bogus type mismatch warnings can be generated.
352 If you need to suppress the type mismatch warnings, you can
353 suppress the inline expansion,
355 #+sbcl (declare (notinline position)) ; to suppress bug 117 bogowarnings
356 (aref *a1* (position x *a2*)))
357 or, sometimes, suppress them by declaring the result to be of an
360 (aref *a1* (the integer (position x *a2*))))
362 This is not a new compiler problem in 0.7.0, but the new compiler
363 transforms for FIND, POSITION, FIND-IF, and POSITION-IF make it
364 more conspicuous. If you don't need performance from these functions,
365 and the bogus warnings are a nuisance for you, you can return to
366 your pre-0.7.0 state of grace with
367 #+sbcl (declaim (notinline find position find-if position-if)) ; bug 117..
370 as reported by Eric Marsden on cmucl-imp@cons.org 2001-08-14:
371 (= (FLOAT 1 DOUBLE-FLOAT-EPSILON)
372 (+ (FLOAT 1 DOUBLE-FLOAT-EPSILON) DOUBLE-FLOAT-EPSILON)) => T
373 when of course it should be NIL. (He says it only fails for X86,
374 not SPARC; dunno about Alpha.)
376 Also, "the same problem exists for LONG-FLOAT-EPSILON,
377 DOUBLE-FLOAT-NEGATIVE-EPSILON, LONG-FLOAT-NEGATIVE-EPSILON (though
378 for the -negative- the + is replaced by a - in the test)."
380 Raymond Toy comments that this is tricky on the X86 since its FPU
381 uses 80-bit precision internally.
384 Even in sbcl-0.pre7.x, which is supposed to be free of the old
385 non-ANSI behavior of treating the function return type inferred
386 from the current function definition as a declaration of the
387 return type from any function of that name, the return type of NIL
388 is attached to FOO in 120a above, and used to optimize code which
392 As of version 0.pre7.14, SBCL's implementation of MACROLET makes
393 the entire lexical environment at the point of MACROLET available
394 in the bodies of the macroexpander functions. In particular, it
395 allows the function bodies (which run at compile time) to try to
396 access lexical variables (which are only defined at runtime).
397 It doesn't even issue a warning, which is bad.
399 The SBCL behavior arguably conforms to the ANSI spec (since the
400 spec says that the behavior is undefined, ergo anything conforms).
401 However, it would be better to issue a compile-time error.
402 Unfortunately I (WHN) don't see any simple way to detect this
403 condition in order to issue such an error, so for the meantime
404 SBCL just does this weird broken "conforming" thing.
406 The ANSI standard says, in the definition of the special operator
408 The macro-expansion functions defined by MACROLET are defined
409 in the lexical environment in which the MACROLET form appears.
410 Declarations and MACROLET and SYMBOL-MACROLET definitions affect
411 the local macro definitions in a MACROLET, but the consequences
412 are undefined if the local macro definitions reference any
413 local variable or function bindings that are visible in that
415 Then it seems to contradict itself by giving the example
417 (macrolet ((fudge (z)
418 ;The parameters x and flag are not accessible
419 ; at this point; a reference to flag would be to
420 ; the global variable of that name.
421 ` (if flag (* ,z ,z) ,z)))
422 ;The parameters x and flag are accessible here.
426 The comment "a reference to flag would be to the global variable
427 of the same name" sounds like good behavior for the system to have.
428 but actual specification quoted above says that the actual behavior
431 (Since 0.7.8.23 macroexpanders are defined in a restricted version
432 of the lexical environment, containing no lexical variables and
433 functions, which seems to conform to ANSI and CLtL2, but signalling
434 a STYLE-WARNING for references to variables similar to locals might
438 (as reported by Gabe Garza on cmucl-help 2001-09-21)
440 (defun test-pred (x y)
444 (func (lambda () x)))
445 (print (eq func func))
446 (print (test-pred func func))
447 (delete func (list func))))
448 Now calling (TEST-CASE) gives output
451 (#<FUNCTION {500A9EF9}>)
452 Evidently Python thinks of the lambda as a code transformation so
453 much that it forgets that it's also an object.
456 Ideally, uninterning a symbol would allow it, and its associated
457 FDEFINITION and PROCLAIM data, to be reclaimed by the GC. However,
458 at least as of sbcl-0.7.0, this isn't the case. Information about
459 FDEFINITIONs and PROCLAIMed properties is stored in globaldb.lisp
460 essentially in ordinary (non-weak) hash tables keyed by symbols.
461 Thus, once a system has an entry in this system, it tends to live
462 forever, even when it is uninterned and all other references to it
465 141: "pretty printing and backquote"
468 ``(FOO SB-IMPL::BACKQ-COMMA-AT S)
471 * (write '`(, .ala.) :readably t :pretty t)
474 (note the space between the comma and the point)
477 (reported by Jesse Bouwman 2001-10-24 through the unfortunately
478 prominent SourceForge web/db bug tracking system, which is
479 unfortunately not a reliable way to get a timely response from
480 the SBCL maintainers)
481 In the course of trying to build a test case for an
482 application error, I encountered this behavior:
483 If you start up sbcl, and then lay on CTRL-C for a
484 minute or two, the lisp process will eventually say:
485 %PRIMITIVE HALT called; the party is over.
486 and throw you into the monitor. If I start up lisp,
487 attach to the process with strace, and then do the same
488 (abusive) thing, I get instead:
489 access failure in heap page not marked as write-protected
490 and the monitor again. I don't know enough to have the
491 faintest idea of what is going on here.
492 This is with sbcl 6.12, uname -a reports:
493 Linux prep 2.2.19 #4 SMP Tue Apr 24 13:59:52 CDT 2001 i686 unknown
494 I (WHN) have verified that the same thing occurs on sbcl-0.pre7.141
495 under OpenBSD 2.9 on my X86 laptop. Do be patient when you try it:
496 it took more than two minutes (but less than five) for me.
499 ANSI allows types `(COMPLEX ,FOO) to use very hairy values for
500 FOO, e.g. (COMPLEX (AND REAL (SATISFIES ODDP))). The old CMU CL
501 COMPLEX implementation didn't deal with this, and hasn't been
502 upgraded to do so. (This doesn't seem to be a high priority
503 conformance problem, since seems hard to construct useful code
507 Floating point errors are reported poorly. E.g. on x86 OpenBSD
510 debugger invoked on condition of type SB-KERNEL:FLOATING-POINT-EXCEPTION:
511 An arithmetic error SB-KERNEL:FLOATING-POINT-EXCEPTION was signalled.
512 No traps are enabled? How can this be?
513 It should be possible to be much more specific (overflow, division
514 by zero, etc.) and of course the "How can this be?" should be fixable.
516 See also bugs #45.c and #183
519 (reported by Robert E. Brown 2002-04-16)
520 When a function is called with too few arguments, causing the
521 debugger to be entered, the uninitialized slots in the bad call frame
522 seem to cause GCish problems, being interpreted as tagged data even
523 though they're not. In particular, executing ROOM in the
524 debugger at that point causes AVER failures:
527 * (lisp-implementation-version)
533 failed AVER: "(SAP= CURRENT END)"
534 (Christophe Rhodes reports that this doesn't occur on the SPARC, which
535 isn't too surprising since there are many differences in stack
536 implementation and GC conservatism between the X86 and other ports.)
539 In sbcl-0.7.3.11, compiling the (illegal) code
540 (in-package :cl-user)
541 (defmethod prove ((uustk uustk))
544 gives the (not terribly clear) error message
546 ; (during macroexpansion of (DEFMETHOD PROVE ...))
547 ; can't get template for (FROB NIL NIL)
548 The problem seems to be that the code walker used by the DEFMETHOD
549 macro is unhappy with the illegal syntax in the method body, and
550 is giving an unclear error message.
553 The compiler sometimes tries to constant-fold expressions before
554 it checks to see whether they can be reached. This can lead to
555 bogus warnings about errors in the constant folding, e.g. in code
558 (WRITE-STRING (> X 0) "+" "0"))
559 compiled in a context where the compiler can prove that X is NIL,
560 and the compiler complains that (> X 0) causes a type error because
561 NIL isn't a valid argument to #'>. Until sbcl-0.7.4.10 or so this
562 caused a full WARNING, which made the bug really annoying because then
563 COMPILE and COMPILE-FILE returned FAILURE-P=T for perfectly legal
564 code. Since then the warning has been downgraded to STYLE-WARNING,
565 so it's still a bug but at least it's a little less annoying.
567 183: "IEEE floating point issues"
568 Even where floating point handling is being dealt with relatively
569 well (as of sbcl-0.7.5, on sparc/sunos and alpha; see bug #146), the
570 accrued-exceptions and current-exceptions part of the fp control
571 word don't seem to bear much relation to reality. E.g. on
575 debugger invoked on condition of type DIVISION-BY-ZERO:
576 arithmetic error DIVISION-BY-ZERO signalled
577 0] (sb-vm::get-floating-point-modes)
579 (:TRAPS (:OVERFLOW :INVALID :DIVIDE-BY-ZERO)
580 :ROUNDING-MODE :NEAREST
581 :CURRENT-EXCEPTIONS NIL
582 :ACCRUED-EXCEPTIONS (:INEXACT)
585 * (sb-vm::get-floating-point-modes)
586 (:TRAPS (:OVERFLOW :INVALID :DIVIDE-BY-ZERO)
587 :ROUNDING-MODE :NEAREST
588 :CURRENT-EXCEPTIONS (:INEXACT)
589 :ACCRUED-EXCEPTIONS (:INEXACT)
592 188: "compiler performance fiasco involving type inference and UNION-TYPE"
596 (declare (optimize (safety 3)))
597 (declare (optimize (compilation-speed 2)))
598 (declare (optimize (speed 1) (debug 1) (space 1)))
600 (declare (type (integer 0) start))
601 (print (incf start 22))
602 (print (incf start 26))
603 (print (incf start 28)))
605 (declare (type (integer 0) start))
606 (print (incf start 22))
607 (print (incf start 26)))
609 (declare (type (integer 0) start))
610 (print (incf start 22))
611 (print (incf start 26))))))
613 This example could be solved with clever enough constraint
614 propagation or with SSA, but consider
619 The careful type of X is {2k} :-(. Is it really important to be
620 able to work with unions of many intervals?
622 190: "PPC/Linux pipe? buffer? bug"
623 In sbcl-0.7.6, the run-program.test.sh test script sometimes hangs
624 on the PPC/Linux platform, waiting for a zombie env process. This
625 is a classic symptom of buffer filling and deadlock, but it seems
626 only sporadically reproducible.
628 191: "Miscellaneous PCL deficiencies"
629 (reported by Alexey Dejneka sbcl-devel 2002-08-04)
630 a. DEFCLASS does not inform the compiler about generated
631 functions. Compiling a file with
635 (WITH-SLOTS (A-CLASS-X) A
637 results in a STYLE-WARNING:
639 SB-SLOT-ACCESSOR-NAME::|COMMON-LISP-USER A-CLASS-X slot READER|
641 APD's fix for this was checked in to sbcl-0.7.6.20, but Pierre
642 Mai points out that the declamation of functions is in fact
643 incorrect in some cases (most notably for structure
644 classes). This means that at present erroneous attempts to use
645 WITH-SLOTS and the like on classes with metaclass STRUCTURE-CLASS
646 won't get the corresponding STYLE-WARNING.
647 c. the examples in CLHS 7.6.5.1 (regarding generic function lambda
648 lists and &KEY arguments) do not signal errors when they should.
650 201: "Incautious type inference from compound types"
651 a. (reported by APD sbcl-devel 2002-09-17)
653 (LET ((Y (CAR (THE (CONS INTEGER *) X))))
655 (FORMAT NIL "~S IS ~S, Y = ~S"
662 (FOO ' (1 . 2)) => "NIL IS INTEGER, Y = 1"
666 (declare (type (array * (4 4)) x))
668 (setq x (make-array '(4 4)))
669 (adjust-array y '(3 5))
670 (= (array-dimension y 0) (eval `(array-dimension ,y 0)))))
672 * (foo (make-array '(4 4) :adjustable t))
675 205: "environment issues in cross compiler"
676 (These bugs have no impact on user code, but should be fixed or
678 a. Macroexpanders introduced with MACROLET are defined in the null
680 b. The body of (EVAL-WHEN (:COMPILE-TOPLEVEL) ...) is evaluated in
681 the null lexical environment.
682 c. The cross-compiler cannot inline functions defined in a non-null
685 206: ":SB-FLUID feature broken"
686 (reported by Antonio Martinez-Shotton sbcl-devel 2002-10-07)
687 Enabling :SB-FLUID in the target-features list in sbcl-0.7.8 breaks
690 207: "poorly distributed SXHASH results for compound data"
691 SBCL's SXHASH could probably try a little harder. ANSI: "the
692 intent is that an implementation should make a good-faith
693 effort to produce hash-codes that are well distributed
694 within the range of non-negative fixnums". But
695 (let ((hits (make-hash-table)))
698 (let* ((ij (cons i j))
699 (newlist (push ij (gethash (sxhash ij) hits))))
701 (format t "~&collision: ~S~%" newlist))))))
702 reports lots of collisions in sbcl-0.7.8. A stronger MIX function
703 would be an obvious way of fix. Maybe it would be acceptably efficient
704 to redo MIX using a lookup into a 256-entry s-box containing
705 29-bit pseudorandom numbers?
707 211: "keywords processing"
708 a. :ALLOW-OTHER-KEYS T should allow a function to receive an odd
709 number of keyword arguments.
712 (flet ((foo (&key y) (list y)))
713 (list (foo :y 1 :y 2)))
715 issues confusing message
720 ; caught STYLE-WARNING:
721 ; The variable #:G15 is defined but never used.
723 212: "Sequence functions and circular arguments"
724 COERCE, MERGE and CONCATENATE go into an infinite loop when given
725 circular arguments; it would be good for the user if they could be
726 given an error instead (ANSI 17.1.1 allows this behaviour on the part
727 of the implementation, as conforming code cannot give non-proper
728 sequences to these functions. MAP also has this problem (and
729 solution), though arguably the convenience of being able to do
730 (MAP 'LIST '+ FOO '#1=(1 . #1#))
731 might be classed as more important (though signalling an error when
732 all of the arguments are circular is probably desireable).
734 213: "Sequence functions and type checking"
735 a. MAKE-SEQUENCE, COERCE, MERGE and CONCATENATE cannot deal with
736 various complicated, though recognizeable, CONS types [e.g.
737 (CONS * (CONS * NULL))
738 which according to ANSI should be recognized] (and, in SAFETY 3
739 code, should return a list of LENGTH 2 or signal an error)
740 b. MAP, when given a type argument that is SUBTYPEP LIST, does not
741 check that it will return a sequence of the given type. Fixing
742 it along the same lines as the others (cf. work done around
743 sbcl-0.7.8.45) is possible, but doing so efficiently didn't look
744 entirely straightforward.
745 c. All of these functions will silently accept a type of the form
747 whether or not the return value is of this type. This is
748 probably permitted by ANSI (see "Exceptional Situations" under
749 ANSI MAKE-SEQUENCE), but the DERIVE-TYPE mechanism does not
750 know about this escape clause, so code of the form
751 (INTEGERP (CAR (MAKE-SEQUENCE '(CONS INTEGER *) 2)))
752 can erroneously return T.
755 SBCL 0.6.12.43 fails to compile
758 (declare (optimize (inhibit-warnings 0) (compilation-speed 2)))
759 (flet ((foo (&key (x :vx x-p)) (list x x-p)))
762 or a more simple example:
765 (declare (optimize (inhibit-warnings 0) (compilation-speed 2)))
766 (lambda (x) (declare (fixnum x)) (if (< x 0) 0 (1- x))))
768 215: ":TEST-NOT handling by functions"
769 a. FIND and POSITION currently signal errors when given non-NIL for
770 both their :TEST and (deprecated) :TEST-NOT arguments, but by
771 ANSI 17.2 "the consequences are unspecified", which by ANSI 1.4.2
772 means that the effect is "unpredictable but harmless". It's not
773 clear what that actually means; it may preclude conforming
774 implementations from signalling errors.
775 b. COUNT, REMOVE and the like give priority to a :TEST-NOT argument
776 when conflict occurs. As a quality of implementation issue, it
777 might be preferable to treat :TEST and :TEST-NOT as being in some
778 sense the same &KEY, and effectively take the first test function in
780 c. Again, a quality of implementation issue: it would be good to issue a
781 STYLE-WARNING at compile-time for calls with :TEST-NOT, and a
782 WARNING for calls with both :TEST and :TEST-NOT; possibly this
783 latter should be WARNed about at execute-time too.
785 216: "debugger confused by frames with invalid number of arguments"
786 In sbcl-0.7.8.51, executing e.g. (VECTOR-PUSH-EXTEND T), BACKTRACE, Q
787 leaves the system confused, enough so that (QUIT) no longer works.
788 It's as though the process of working with the uninitialized slot in
789 the bad VECTOR-PUSH-EXTEND frame causes GC problems, though that may
790 not be the actual problem. (CMU CL 18c doesn't have problems with this.)
792 217: "Bad type operations with FUNCTION types"
795 * (values-type-union (specifier-type '(function (base-char)))
796 (specifier-type '(function (integer))))
798 #<FUN-TYPE (FUNCTION (BASE-CHAR) *)>
800 It causes insertion of wrong type assertions into generated
804 (let ((f (etypecase x
805 (character #'write-char)
806 (integer #'write-byte))))
809 (character (write-char x s))
810 (integer (write-byte x s)))))
812 Then (FOO #\1 *STANDARD-OUTPUT*) signals type error.
814 (In 0.7.9.1 the result type is (FUNCTION * *), so Python does not
815 produce invalid code, but type checking is not accurate.)
817 233: bugs in constraint propagation
820 (declare (optimize (speed 2) (safety 3)))
826 (quux y (+ y 2d0) (* y 3d0)))))
827 (foo 4) => segmentation violation
829 (see usage of CONTINUATION-ASSERTED-TYPE in USE-RESULT-CONSTRAINTS)
833 (declaim (optimize (speed 2) (safety 3)))
835 (if (typep (prog1 x (setq x y)) 'double-float)
838 (foo 1d0 5) => segmentation violation
840 235: "type system and inline expansion"
842 (declaim (ftype (function (cons) number) acc))
843 (declaim (inline acc))
845 (the number (car c)))
848 (values (locally (declare (optimize (safety 0)))
850 (locally (declare (optimize (safety 3)))
853 (foo '(nil) '(t)) => NIL, T.
855 237: "Environment arguments to type functions"
856 a. Functions SUBTYPEP, TYPEP, UPGRADED-ARRAY-ELEMENT-TYPE, and
857 UPGRADED-COMPLEX-PART-TYPE now have an optional environment
858 argument, but they ignore it completely. This is almost
859 certainly not correct.
860 b. Also, the compiler's optimizers for TYPEP have not been informed
861 about the new argument; consequently, they will not transform
862 calls of the form (TYPEP 1 'INTEGER NIL), even though this is
863 just as optimizeable as (TYPEP 1 'INTEGER).
865 238: "REPL compiler overenthusiasm for CLOS code"
867 * (defclass foo () ())
868 * (defmethod bar ((x foo) (foo foo)) (call-next-method))
869 causes approximately 100 lines of code deletion notes. Some
870 discussion on this issue happened under the title 'Three "interesting"
871 bugs in PCL', resulting in a fix for this oververbosity from the
872 compiler proper; however, the problem persists in the interactor
873 because the notion of original source is not preserved: for the
874 compiler, the original source of the above expression is (DEFMETHOD
875 BAR ((X FOO) (FOO FOO)) (CALL-NEXT-METHOD)), while by the time the
876 compiler gets its hands on the code needing compilation from the REPL,
877 it has been macroexpanded several times.
879 A symptom of the same underlying problem, reported by Tony Martinez:
881 (with-input-from-string (*query-io* " no")
883 (simple-type-error () 'error))
885 ; (SB-KERNEL:FLOAT-WAIT)
887 ; note: deleting unreachable code
888 ; compilation unit finished
891 241: "DEFCLASS mysteriously remembers uninterned accessor names."
892 (from tonyms on #lisp IRC 2003-02-25)
893 In sbcl-0.7.12.55, typing
894 (defclass foo () ((bar :accessor foo-bar)))
897 (defclass foo () ((bar :accessor foo-bar)))
898 gives the error message
899 "#:FOO-BAR already names an ordinary function or a macro."
900 So it's somehow checking the uninterned old accessor name instead
901 of the new requested accessor name, which seems broken to me (WHN).
903 242: "WRITE-SEQUENCE suboptimality"
904 (observed from clx performance)
905 In sbcl-0.7.13, WRITE-SEQUENCE of a sequence of type
906 (SIMPLE-ARRAY (UNSIGNED-BYTE 8) (*)) on a stream with element-type
907 (UNSIGNED-BYTE 8) will write to the stream one byte at a time,
908 rather than writing the sequence in one go, leading to severe
909 performance degradation.
911 243: "STYLE-WARNING overenthusiasm for unused variables"
912 (observed from clx compilation)
913 In sbcl-0.7.14, in the presence of the macros
914 (DEFMACRO FOO (X) `(BAR ,X))
915 (DEFMACRO BAR (X) (DECLARE (IGNORABLE X)) 'NIL)
916 somewhat surprising style warnings are emitted for
917 (COMPILE NIL '(LAMBDA (Y) (FOO Y))):
919 ; (LAMBDA (Y) (FOO Y))
921 ; caught STYLE-WARNING:
922 ; The variable Y is defined but never used.
924 245: bugs in disassembler
925 a. On X86 an immediate operand for IMUL is printed incorrectly.
926 b. On X86 operand size prefix is not recognized.
928 248: "reporting errors in type specifier syntax"
929 (TYPEP 1 '(SYMBOL NIL)) says something about "unknown type
933 (defun foo (&key (a :x))
937 does not cause a warning. (BTW: old SBCL issued a warning, but for a
938 function, which was never called!)
941 Compiler does not emit warnings for
943 a. (lambda () (svref (make-array 8 :adjustable t) 1))
946 (list (let ((y (the real x)))
947 (unless (floatp y) (error ""))
952 (declare (optimize (debug 0)))
953 (declare (type vector x))
954 (list (fill-pointer x)
958 Complex array type does not have corresponding type specifier.
960 This is a problem because the compiler emits optimization notes when
961 you use a non-simple array, and without a type specifier for hairy
962 array types, there's no good way to tell it you're doing it
963 intentionally so that it should shut up and just compile the code.
965 Another problem is confusing error message "asserted type ARRAY
966 conflicts with derived type (VALUES SIMPLE-VECTOR &OPTIONAL)" during
967 compiling (LAMBDA (V) (VALUES (SVREF V 0) (VECTOR-POP V))).
969 The last problem is that when type assertions are converted to type
970 checks, types are represented with type specifiers, so we could lose
971 complex attribute. (Now this is probably not important, because
972 currently checks for complex arrays seem to be performed by
976 (compile nil '(lambda () (aref (make-array 0) 0))) compiles without
977 warning. Analogous cases with the index and length being equal and
978 greater than 0 are warned for; the problem here seems to be that the
979 type required for an array reference of this type is (INTEGER 0 (0))
980 which is canonicalized to NIL.
985 (t1 (specifier-type s)))
986 (eval `(defstruct ,s))
987 (type= t1 (specifier-type s)))
992 b. The same for CSUBTYPEP.
995 * (let () (list (the (values &optional fixnum) (eval '(values)))))
996 debugger invoked on condition of type TYPE-ERROR:
997 The value NIL is not of type FIXNUM.
999 262: "yet another bug in inline expansion of local functions"
1003 (declare (integer x y))
1006 (declare (integer u))
1007 (if (> (1+ (the unsigned-byte u)) 0)
1009 (return (+ 38 (cos (/ u 78)))))))
1010 (declare (inline xyz))
1012 (* (funcall (eval #'xyz) x)
1014 (funcall (if (> x 5) #'xyz #'identity)
1019 Urgh... It's time to write IR1-copier.
1022 SB-EXT:RUN-PROGRAM is currently non-functional on Linux/PPC;
1023 attempting to use it leads to segmentation violations. This is
1024 probably because of a bogus implementation of
1025 os_restore_fp_control().
1028 David Lichteblau provided (sbcl-devel 2003-06-01) a patch to fix
1029 behaviour of streams with element-type (SIGNED-BYTE 8). The patch
1030 looks reasonable, if not obviously correct; however, it caused the
1031 PPC/Linux port to segfault during warm-init while loading
1032 src/pcl/std-class.fasl. A workaround patch was made, but it would
1033 be nice to understand why the first patch caused problems, and to
1034 fix the cause if possible.
1041 (fact (1- x) (* x i))))
1042 sbcl does not convert the self-recursive call to a jump, though it
1043 is allowed to by CLHS 3.2.2.3. CMUCL, however, does perform this
1046 268: "wrong free declaration scope"
1047 The following code must signal type error:
1049 (locally (declare (optimize (safety 3)))
1050 (flet ((foo (x &optional (y (car x)))
1051 (declare (optimize (safety 0)))
1053 (funcall (eval #'foo) 1)))
1056 SCALE-FLOAT should accept any integer for its second argument.
1059 In the following function constraint propagator optimizes nothing:
1062 (declare (integer x))
1063 (declare (optimize speed))
1071 Cross-compiler cannot perform constant folding of some internal
1072 functions, such as %NEGATE.
1075 All forms of GC hooks (including notifiers and finalisers) are currently
1076 (since 0.8.0) broken for gencgc (i.e. x86) users
1079 DEFUNCT CATEGORIES OF BUGS
1081 These labels were used for bugs related to the old IR1 interpreter.
1082 The # values reached 6 before the category was closed down.