- PVE's regression tests want them to raise errors. SBCL
- generates the infinities instead, which may or may not be
- conforming behavior, but then blow it by being unable to
- output the infinities, since support for infinities is generally
- broken, and in particular SB-IMPL::OUTPUT-FLOAT-INFINITY is
- undefined.
- * (in section12.erg) various forms a la
- (FLOAT 1 DOUBLE-FLOAT-EPSILON) don't give the right behavior.
-
-* type safety errors reported by Peter Van Eynde July 25, 2000:
- * (COERCE (QUOTE (A B C)) (QUOTE (VECTOR * 4)))
- => #(A B C)
- In general lengths of array type specifications aren't
- checked by COERCE, so it fails when the spec is
- (VECTOR 4), (STRING 2), (SIMPLE-BIT-VECTOR 3), or whatever.
- * CONCATENATE has the same problem of not checking the length
- of specified output array types. MAKE-SEQUENCE and MAP and
- MERGE also have the same problem.
- * (COERCE 'AND 'FUNCTION) returns something related to
- (MACRO-FUNCTION 'AND), but ANSI says it should raise an error.
- * ELT signals SIMPLE-ERROR if its index argument
- isn't a valid index for its sequence argument, but should
- signal TYPE-ERROR instead.
- * FILE-LENGTH is supposed to signal a type error when its
- argument is not a stream associated with a file, but doesn't.
- * (FLOAT-RADIX 2/3) should signal an error instead of
- returning 2.
- * (LOAD "*.lsp") should signal FILE-ERROR.
- * (MAKE-CONCATENATED-STREAM (MAKE-STRING-OUTPUT-STREAM))
- should signal TYPE-ERROR.
- * MAKE-TWO-WAY-STREAM doesn't check that its arguments can
- be used for input and output as needed. It should fail with
- TYPE-ERROR when handed e.g. the results of MAKE-STRING-INPUT-STREAM
- or MAKE-STRING-OUTPUT-STREAM in the inappropriate positions,
- but doesn't.
- * (PARSE-NAMESTRING (COERCE (LIST #\f #\o #\o (CODE-CHAR 0) #\4 #\8)
- (QUOTE STRING)))
- should probably signal an error instead of making a pathname with
- a null byte in it.
- * READ-BYTE is supposed to signal TYPE-ERROR when its argument is
- not a binary input stream, but instead cheerfully reads from
- character streams, e.g. (MAKE-STRING-INPUT-STREAM "abc").
-
-* DEFCLASS bugs reported by Peter Van Eynde July 25, 2000:
- * (DEFCLASS FOO () (A B A)) should signal a PROGRAM-ERROR, and doesn't.
- * (DEFCLASS FOO () (A B A) (:DEFAULT-INITARGS X A X B)) should
- signal a PROGRAM-ERROR, and doesn't.
- * (DEFCLASS FOO07 NIL ((A :ALLOCATION :CLASS :ALLOCATION :CLASS))),
- and other DEFCLASS forms with duplicate specifications in their
- slots, should signal a PROGRAM-ERROR, and doesn't.
- * (DEFGENERIC IF (X)) should signal a PROGRAM-ERROR, but instead
- causes a COMPILER-ERROR.
-
-* SYMBOL-MACROLET bugs reported by Peter Van Eynde July 25, 2000:
- * (SYMBOL-MACROLET ((T TRUE)) ..) should probably signal
- PROGRAM-ERROR, but SBCL accepts it instead.
- * SYMBOL-MACROLET should refuse to bind something which is
- declared as a global variable, signalling PROGRAM-ERROR.
- * SYMBOL-MACROLET should signal PROGRAM-ERROR if something
- it binds is declared SPECIAL inside.
-
-* LOOP bugs reported by Peter Van Eynde July 25, 2000:
- * (LOOP WITH (A B) DO (PRINT 1)) is a syntax error according to
- the definition of WITH clauses given in the ANSI spec, but
- compiles and runs happily in SBCL.
- * a messy one involving package iteration:
-interpreted Form: (LET ((PACKAGE (MAKE-PACKAGE "LOOP-TEST"))) (INTERN "blah" PACKAGE) (LET ((BLAH2 (INTERN "blah2" PACKAGE))) (EXPORT BLAH2 PACKAGE)) (LIST (SORT (LOOP FOR SYM BEING EACH PRESENT-SYMBOL OF PACKAGE FOR SYM-NAME = (SYMBOL-NAME SYM) COLLECT SYM-NAME) (FUNCTION STRING<)) (SORT (LOOP FOR SYM BEING EACH EXTERNAL-SYMBOL OF PACKAGE FOR SYM-NAME = (SYMBOL-NAME SYM) COLLECT SYM-NAME) (FUNCTION STRING<))))
-Should be: (("blah" "blah2") ("blah2"))
-SBCL: (("blah") ("blah2"))
- * (LET ((X 1)) (LOOP FOR I BY (INCF X) FROM X TO 10 COLLECT I))
- doesn't work -- SBCL's LOOP says BY isn't allowed in a FOR clause.
-
-* type system errors reported by Peter Van Eynde July 25, 2000:
- * (SUBTYPEP 'BIGNUM 'INTEGER) => NIL, NIL
- but should be (VALUES T T) instead.
- * (SUBTYPEP 'EXTENDED-CHAR 'CHARACTER) => NIL, NIL
- but should be (VALUES T T) instead.
- * (SUBTYPEP '(INTEGER (0) (0)) 'NIL) dies with nested errors.
- * In general, the system doesn't like '(INTEGER (0) (0)) -- it
- blows up at the level of SPECIFIER-TYPE with
- "Lower bound (0) is greater than upper bound (0)." Probably
- SPECIFIER-TYPE should return NIL instead.
- * (TYPEP 0 '(COMPLEX (EQL 0)) fails with
- "Component type for Complex is not numeric: (EQL 0)."
- This might be easy to fix; the type system already knows
- that (SUBTYPEP '(EQL 0) 'NUMBER) is true.
- * The type system doesn't know about the condition system,
- so that e.g. (TYPEP 'SIMPLE-ERROR 'ERROR)=>NIL.
- * The type system isn't all that smart about relationships
- between hairy types, as shown in the type.erg test results,
- e.g. (SUBTYPEP 'CONS '(NOT ATOM)) => NIL, NIL.
-
-* miscellaneous errors reported by Peter Van Eynde July 25, 2000:
- * (PROGN
- (DEFGENERIC FOO02 (X))
- (DEFMETHOD FOO02 ((X NUMBER)) T)
- (LET ((M (FIND-METHOD (FUNCTION FOO02)
- NIL
- (LIST (FIND-CLASS (QUOTE NUMBER))))))
- (REMOVE-METHOD (FUNCTION FOO02) M)
- (DEFGENERIC FOO03 (X))
- (ADD-METHOD (FUNCTION FOO03) M)))
- should give an error, but SBCL allows it.
- * READ should probably return READER-ERROR, not the bare
- arithmetic error, when input a la "1/0" or "1e1000" causes
- an arithmetic error.
- * There are several metaobject protocol "errors". (In order to fix
- them, we might need to document exactly what metaobject
- protocol specification we're following -- the current code is
- just inherited from PCL.)
- * (BUTLAST NIL) should return NIL. (This appears to be a compiler
- bug, since the definition of BUTLAST, when interpreted, does
- give (BUTLAST NIL)=>NIL.)
-
-* another error from Peter Van Eynde 5 September 2000:
- (FORMAT NIL "~F" "FOO") should work, but instead reports an error.
- PVE submitted a patch to deal with this bug, but it exposes other
- comparably serious bugs, so I didn't apply it. It looks as though
- the FORMAT code needs a fair amount of rewriting in order to comply
- with the various details of the ANSI spec.
-
-* The bug discussed on the cmucl-imp@cons.org mailing list ca. 5 September,
- simplified by Douglas Crosher down to
- (defun tickle-bug ()
- (labels ((fun1 ()
- (fun2))
- (fun2 ()
- (when nil
- (tagbody
- tag
- (fun2)
- (go tag)))
- (when nil
- (tagbody
- tag
- (fun1)
- (go tag)))))
- (fun1)
- nil))
- causes the same problem on SBCL: compiling it fails with
- :LET fell through ECASE expression.
- Very likely the patch discussed there is appropriate for SBCL
- as well, but I don't understand it, so I didn't apply it.
-
-* The implementation of #'+ returns its single argument without
- type checking, e.g. (+ "illegal") => "illegal".
-
-* In sbcl-0.6.7, there is no doc string for CL:PUSH, probably
- because it's defined with the DEFMACRO-MUNDANELY macro and something
- is wrong with doc string setting in that macro.
-
-* Attempting to use COMPILE on something defined by DEFMACRO fails:
- (DEFMACRO FOO (X) (CONS X X))
- (COMPILE 'FOO)
-Error in function C::GET-LAMBDA-TO-COMPILE:
- #<Closure Over Function "DEFUN (SETF MACRO-FUNCTION)" {480E21B1}> was defined in a non-null environment.
-
-* In sbcl-0.6.7, the compiler accepted a bogus declaration
- (TYPE INDEX LENGTH) in the definition of BUTLAST, and then died
- with infinite regress of errors when the BUTLAST function was
- executed with a LIST=NIL which would cause LENGTH to be -1.
- I fixed the bogus declaration, but I should come back and see
- whether the system's inability to recover from the bogus declaration
- (by signalling a TYPE-ERROR and dropping into the debugger) was
- a compiler problem which remains to be fixed, or one of the
- unrelated infinite-regress-errors problems, many related to
- revised signal handling, which were fixed around the same time.
-
-* Even when FINISH-OUTPUT is called, the system doesn't in general
- flush the last line of output unless it's terminated by a newline.
- (This is particularly annoying because several Lisp functions like
- PRINT *precede* their output with a newline, instead of following
- it with a newline.)
+ PVE's regression tests want them to raise errors. sbcl-0.7.0.5
+ on x86/Linux generates the infinities instead. That might or
+ might not be conforming behavior, but it's also inconsistent,
+ which is almost certainly wrong. (Inconsistency: (/ 1 0.0)
+ should give the same result as (/ 1.0 0.0), but instead (/ 1 0.0)
+ generates SINGLE-FLOAT-POSITIVE-INFINITY and (/ 1.0 0.0)
+ signals an error.
+ d: (in section12.erg) various forms a la
+ (FLOAT 1 DOUBLE-FLOAT-EPSILON)
+ don't give the right behavior.
+
+60:
+ The debugger LIST-LOCATIONS command doesn't work properly.
+ (How should it work properly?)
+
+61:
+ Compiling and loading
+ (DEFUN FAIL (X) (THROW 'FAIL-TAG X))
+ (FAIL 12)
+ then requesting a BACKTRACE at the debugger prompt gives no information
+ about where in the user program the problem occurred.
+
+64:
+ Using the pretty-printer from the command prompt gives funny
+ results, apparently because the pretty-printer doesn't know
+ about user's command input, including the user's carriage return
+ that the user, and therefore the pretty-printer thinks that
+ the new output block should start indented 2 or more characters
+ rightward of the correct location.
+
+67:
+ As reported by Winton Davies on a CMU CL mailing list 2000-01-10,
+ and reported for SBCL by Martin Atzmueller 2000-10-20: (TRACE GETHASH)
+ crashes SBCL. In general tracing anything which is used in the
+ implementation of TRACE is likely to have the same problem.
+
+78:
+ ANSI says in one place that type declarations can be abbreviated even
+ when the type name is not a symbol, e.g.
+ (DECLAIM ((VECTOR T) *FOOVECTOR*))
+ SBCL doesn't support this. But ANSI says in another place that this
+ isn't allowed. So it's not clear this is a bug after all. (See the
+ e-mail on cmucl-help@cons.org on 2001-01-16 and 2001-01-17 from WHN
+ and Pierre Mai.)
+
+79:
+ as pointed out by Dan Barlow on sbcl-devel 2000-07-02:
+ The PICK-TEMPORARY-FILE-NAME utility used by LOAD-FOREIGN uses
+ an easily guessable temporary filename in a way which might open
+ applications using LOAD-FOREIGN to hijacking by malicious users
+ on the same machine. Incantations for doing this safely are
+ floating around the net in various "how to write secure programs
+ despite Unix" documents, and it would be good to (1) fix this in
+ LOAD-FOREIGN, and (2) hunt for any other code which uses temporary
+ files and make it share the same new safe logic.
+
+ (partially alleviated in sbcl-0.7.9.32 by a fix by Matthew Danish to
+ make the temporary filename less easily guessable)
+
+83:
+ RANDOM-INTEGER-EXTRA-BITS=10 may not be large enough for the RANDOM
+ RNG to be high quality near RANDOM-FIXNUM-MAX; it looks as though
+ the mean of the distribution can be systematically O(0.1%) wrong.
+ Just increasing R-I-E-B is probably not a good solution, since
+ it would decrease efficiency more than is probably necessary. Perhaps
+ using some sort of accept/reject method would be better.
+
+85:
+ Internally the compiler sometimes evaluates
+ (sb-kernel:type/= (specifier-type '*) (specifier-type t))
+ (I stumbled across this when I added an
+ (assert (not (eq type1 *wild-type*)))
+ in the NAMED :SIMPLE-= type method.) '* isn't really a type, and
+ in a type context should probably be translated to T, and so it's
+ probably wrong to ask whether it's equal to the T type and then (using
+ the EQ type comparison in the NAMED :SIMPLE-= type method) return NIL.
+ (I haven't tried to investigate this bug enough to guess whether
+ there might be any user-level symptoms.)
+
+ In fact, the type system is likely to depend on this inequality not
+ holding... * is not equivalent to T in many cases, such as
+ (VECTOR *) /= (VECTOR T).
+
+95:
+ The facility for dumping a running Lisp image to disk gets confused
+ when run without the PURIFY option, and creates an unnecessarily large
+ core file (apparently representing memory usage up to the previous
+ high-water mark). Moreover, when the file is loaded, it confuses the
+ GC, so that thereafter memory usage can never be reduced below that
+ level.
+
+98:
+ In sbcl-0.6.11.41 (and in all earlier SBCL, and in CMU
+ CL), out-of-line structure slot setters are horribly inefficient
+ whenever the type of the slot is declared, because out-of-line
+ structure slot setters are implemented as closures to save space,
+ so the compiler doesn't compile the type test into code, but
+ instead just saves the type in a lexical closure and interprets it
+ at runtime.
+ To exercise the problem, compile and load
+ (cl:in-package :cl-user)
+ (defstruct foo
+ (bar (error "missing") :type bar))
+ (defvar *foo*)
+ (defun wastrel1 (x)
+ (loop (setf (foo-bar *foo*) x)))
+ (defstruct bar)
+ (defvar *bar* (make-bar))
+ (defvar *foo* (make-foo :bar *bar*))
+ (defvar *setf-foo-bar* #'(setf foo-bar))
+ (defun wastrel2 (x)
+ (loop (funcall *setf-foo-bar* x *foo*)))
+ then run (WASTREL1 *BAR*) or (WASTREL2 *BAR*), hit Ctrl-C, and
+ use BACKTRACE, to see it's spending all essentially all its time
+ in %TYPEP and VALUES-SPECIFIER-TYPE and so forth.
+ One possible solution would be simply to give up on
+ representing structure slot accessors as functions, and represent
+ them as macroexpansions instead. This can be inconvenient for users,
+ but it's not clear that it's worse than trying to help by expanding
+ into a horribly inefficient implementation.
+ As a workaround for the problem, #'(SETF FOO) expressions
+ can be replaced with (EFFICIENT-SETF-FUNCTION FOO), where
+(defmacro efficient-setf-function (place-function-name)
+ (or #+sbcl (and (sb-int:info :function :accessor-for place-function-name)
+ ;; a workaround for the problem, encouraging the
+ ;; inline expansion of the structure accessor, so
+ ;; that the compiler can optimize its type test
+ (let ((new-value (gensym "NEW-VALUE-"))
+ (structure-value (gensym "STRUCTURE-VALUE-")))
+ `(lambda (,new-value ,structure-value)
+ (setf (,place-function-name ,structure-value)
+ ,new-value))))
+ ;; no problem, can just use the ordinary expansion
+ `(function (setf ,place-function-name))))
+
+100:
+ There's apparently a bug in CEILING optimization which caused
+ Douglas Crosher to patch the CMU CL version. Martin Atzmueller
+ applied the patches to SBCL and they didn't seem to cause problems
+ (as reported sbcl-devel 2001-05-04). However, since the patches
+ modify nontrivial code which was apparently written incorrectly
+ the first time around, until regression tests are written I'm not
+ comfortable merging the patches in the CVS version of SBCL.
+
+108:
+ (TIME (ROOM T)) reports more than 200 Mbytes consed even for
+ a clean, just-started SBCL system. And it seems to be right:
+ (ROOM T) can bring a small computer to its knees for a *long*
+ time trying to GC afterwards. Surely there's some more economical
+ way to implement (ROOM T).
+
+117:
+ When the compiler inline expands functions, it may be that different
+ kinds of return values are generated from different code branches.
+ E.g. an inline expansion of POSITION generates integer results
+ from one branch, and NIL results from another. When that inline
+ expansion is used in a context where only one of those results
+ is acceptable, e.g.
+ (defun foo (x)
+ (aref *a1* (position x *a2*)))
+ and the compiler can't prove that the unacceptable branch is
+ never taken, then bogus type mismatch warnings can be generated.
+ If you need to suppress the type mismatch warnings, you can
+ suppress the inline expansion,
+ (defun foo (x)
+ #+sbcl (declare (notinline position)) ; to suppress bug 117 bogowarnings
+ (aref *a1* (position x *a2*)))
+ or, sometimes, suppress them by declaring the result to be of an
+ appropriate type,
+ (defun foo (x)
+ (aref *a1* (the integer (position x *a2*))))
+
+ This is not a new compiler problem in 0.7.0, but the new compiler
+ transforms for FIND, POSITION, FIND-IF, and POSITION-IF make it
+ more conspicuous. If you don't need performance from these functions,
+ and the bogus warnings are a nuisance for you, you can return to
+ your pre-0.7.0 state of grace with
+ #+sbcl (declaim (notinline find position find-if position-if)) ; bug 117..
+
+ (see also bug 279)
+
+118:
+ as reported by Eric Marsden on cmucl-imp@cons.org 2001-08-14:
+ (= (FLOAT 1 DOUBLE-FLOAT-EPSILON)
+ (+ (FLOAT 1 DOUBLE-FLOAT-EPSILON) DOUBLE-FLOAT-EPSILON)) => T
+ when of course it should be NIL. (He says it only fails for X86,
+ not SPARC; dunno about Alpha.)
+
+ Also, "the same problem exists for LONG-FLOAT-EPSILON,
+ DOUBLE-FLOAT-NEGATIVE-EPSILON, LONG-FLOAT-NEGATIVE-EPSILON (though
+ for the -negative- the + is replaced by a - in the test)."
+
+ Raymond Toy comments that this is tricky on the X86 since its FPU
+ uses 80-bit precision internally.
+
+124:
+ As of version 0.pre7.14, SBCL's implementation of MACROLET makes
+ the entire lexical environment at the point of MACROLET available
+ in the bodies of the macroexpander functions. In particular, it
+ allows the function bodies (which run at compile time) to try to
+ access lexical variables (which are only defined at runtime).
+ It doesn't even issue a warning, which is bad.
+
+ The SBCL behavior arguably conforms to the ANSI spec (since the
+ spec says that the behavior is undefined, ergo anything conforms).
+ However, it would be better to issue a compile-time error.
+ Unfortunately I (WHN) don't see any simple way to detect this
+ condition in order to issue such an error, so for the meantime
+ SBCL just does this weird broken "conforming" thing.
+
+ The ANSI standard says, in the definition of the special operator
+ MACROLET,
+ The macro-expansion functions defined by MACROLET are defined
+ in the lexical environment in which the MACROLET form appears.
+ Declarations and MACROLET and SYMBOL-MACROLET definitions affect
+ the local macro definitions in a MACROLET, but the consequences
+ are undefined if the local macro definitions reference any
+ local variable or function bindings that are visible in that
+ lexical environment.
+ Then it seems to contradict itself by giving the example
+ (defun foo (x flag)
+ (macrolet ((fudge (z)
+ ;The parameters x and flag are not accessible
+ ; at this point; a reference to flag would be to
+ ; the global variable of that name.
+ ` (if flag (* ,z ,z) ,z)))
+ ;The parameters x and flag are accessible here.
+ (+ x
+ (fudge x)
+ (fudge (+ x 1)))))
+ The comment "a reference to flag would be to the global variable
+ of the same name" sounds like good behavior for the system to have.
+ but actual specification quoted above says that the actual behavior
+ is undefined.
+
+ (Since 0.7.8.23 macroexpanders are defined in a restricted version
+ of the lexical environment, containing no lexical variables and
+ functions, which seems to conform to ANSI and CLtL2, but signalling
+ a STYLE-WARNING for references to variables similar to locals might
+ be a good thing.)
+
+125:
+ (as reported by Gabe Garza on cmucl-help 2001-09-21)
+ (defvar *tmp* 3)
+ (defun test-pred (x y)
+ (eq x y))
+ (defun test-case ()
+ (let* ((x *tmp*)
+ (func (lambda () x)))
+ (print (eq func func))
+ (print (test-pred func func))
+ (delete func (list func))))
+ Now calling (TEST-CASE) gives output
+ NIL
+ NIL
+ (#<FUNCTION {500A9EF9}>)
+ Evidently Python thinks of the lambda as a code transformation so
+ much that it forgets that it's also an object.
+
+135:
+ Ideally, uninterning a symbol would allow it, and its associated
+ FDEFINITION and PROCLAIM data, to be reclaimed by the GC. However,
+ at least as of sbcl-0.7.0, this isn't the case. Information about
+ FDEFINITIONs and PROCLAIMed properties is stored in globaldb.lisp
+ essentially in ordinary (non-weak) hash tables keyed by symbols.
+ Thus, once a system has an entry in this system, it tends to live
+ forever, even when it is uninterned and all other references to it
+ are lost.
+
+141: "pretty printing and backquote"
+ a.
+ * '``(FOO ,@',@S)
+ ``(FOO SB-IMPL::BACKQ-COMMA-AT S)
+
+ b. (fixed in 0.8.4.7)
+
+143:
+ (reported by Jesse Bouwman 2001-10-24 through the unfortunately
+ prominent SourceForge web/db bug tracking system, which is
+ unfortunately not a reliable way to get a timely response from
+ the SBCL maintainers)
+ In the course of trying to build a test case for an
+ application error, I encountered this behavior:
+ If you start up sbcl, and then lay on CTRL-C for a
+ minute or two, the lisp process will eventually say:
+ %PRIMITIVE HALT called; the party is over.
+ and throw you into the monitor. If I start up lisp,
+ attach to the process with strace, and then do the same
+ (abusive) thing, I get instead:
+ access failure in heap page not marked as write-protected
+ and the monitor again. I don't know enough to have the
+ faintest idea of what is going on here.
+ This is with sbcl 6.12, uname -a reports:
+ Linux prep 2.2.19 #4 SMP Tue Apr 24 13:59:52 CDT 2001 i686 unknown
+ I (WHN) have verified that the same thing occurs on sbcl-0.pre7.141
+ under OpenBSD 2.9 on my X86 laptop. Do be patient when you try it:
+ it took more than two minutes (but less than five) for me.
+
+145:
+ a.
+ ANSI allows types `(COMPLEX ,FOO) to use very hairy values for
+ FOO, e.g. (COMPLEX (AND REAL (SATISFIES ODDP))). The old CMU CL
+ COMPLEX implementation didn't deal with this, and hasn't been
+ upgraded to do so. (This doesn't seem to be a high priority
+ conformance problem, since seems hard to construct useful code
+ where it matters.)
+
+ b. (fixed in 0.8.3.43)
+
+146:
+ Floating point errors are reported poorly. E.g. on x86 OpenBSD
+ with sbcl-0.7.1,
+ * (expt 2.0 12777)
+ debugger invoked on condition of type SB-KERNEL:FLOATING-POINT-EXCEPTION:
+ An arithmetic error SB-KERNEL:FLOATING-POINT-EXCEPTION was signalled.
+ No traps are enabled? How can this be?
+ It should be possible to be much more specific (overflow, division
+ by zero, etc.) and of course the "How can this be?" should be fixable.
+
+ See also bugs #45.c and #183
+
+162:
+ (reported by Robert E. Brown 2002-04-16)
+ When a function is called with too few arguments, causing the
+ debugger to be entered, the uninitialized slots in the bad call frame
+ seem to cause GCish problems, being interpreted as tagged data even
+ though they're not. In particular, executing ROOM in the
+ debugger at that point causes AVER failures:
+ * (machine-type)
+ "X86"
+ * (lisp-implementation-version)
+ "0.7.2.12"
+ * (typep 10)
+ ...
+ 0] (room)
+ ...
+ failed AVER: "(SAP= CURRENT END)"
+ (Christophe Rhodes reports that this doesn't occur on the SPARC, which
+ isn't too surprising since there are many differences in stack
+ implementation and GC conservatism between the X86 and other ports.)
+
+ This is probably the same bug as 216
+
+167:
+ In sbcl-0.7.3.11, compiling the (illegal) code
+ (in-package :cl-user)
+ (defmethod prove ((uustk uustk))
+ (zap ((frob () nil))
+ (frob)))
+ gives the (not terribly clear) error message
+ ; caught ERROR:
+ ; (during macroexpansion of (DEFMETHOD PROVE ...))
+ ; can't get template for (FROB NIL NIL)
+ The problem seems to be that the code walker used by the DEFMETHOD
+ macro is unhappy with the illegal syntax in the method body, and
+ is giving an unclear error message.
+
+173:
+ The compiler sometimes tries to constant-fold expressions before
+ it checks to see whether they can be reached. This can lead to
+ bogus warnings about errors in the constant folding, e.g. in code
+ like
+ (WHEN X
+ (WRITE-STRING (> X 0) "+" "0"))
+ compiled in a context where the compiler can prove that X is NIL,
+ and the compiler complains that (> X 0) causes a type error because
+ NIL isn't a valid argument to #'>. Until sbcl-0.7.4.10 or so this
+ caused a full WARNING, which made the bug really annoying because then
+ COMPILE and COMPILE-FILE returned FAILURE-P=T for perfectly legal
+ code. Since then the warning has been downgraded to STYLE-WARNING,
+ so it's still a bug but at least it's a little less annoying.
+
+183: "IEEE floating point issues"
+ Even where floating point handling is being dealt with relatively
+ well (as of sbcl-0.7.5, on sparc/sunos and alpha; see bug #146), the
+ accrued-exceptions and current-exceptions part of the fp control
+ word don't seem to bear much relation to reality. E.g. on
+ SPARC/SunOS:
+ * (/ 1.0 0.0)
+
+ debugger invoked on condition of type DIVISION-BY-ZERO:
+ arithmetic error DIVISION-BY-ZERO signalled
+ 0] (sb-vm::get-floating-point-modes)
+
+ (:TRAPS (:OVERFLOW :INVALID :DIVIDE-BY-ZERO)
+ :ROUNDING-MODE :NEAREST
+ :CURRENT-EXCEPTIONS NIL
+ :ACCRUED-EXCEPTIONS (:INEXACT)
+ :FAST-MODE NIL)
+ 0] abort
+ * (sb-vm::get-floating-point-modes)
+ (:TRAPS (:OVERFLOW :INVALID :DIVIDE-BY-ZERO)
+ :ROUNDING-MODE :NEAREST
+ :CURRENT-EXCEPTIONS (:INEXACT)
+ :ACCRUED-EXCEPTIONS (:INEXACT)
+ :FAST-MODE NIL)
+
+188: "compiler performance fiasco involving type inference and UNION-TYPE"
+ (time (compile
+ nil
+ '(lambda ()
+ (declare (optimize (safety 3)))
+ (declare (optimize (compilation-speed 2)))
+ (declare (optimize (speed 1) (debug 1) (space 1)))
+ (let ((start 4))
+ (declare (type (integer 0) start))
+ (print (incf start 22))
+ (print (incf start 26))
+ (print (incf start 28)))
+ (let ((start 6))
+ (declare (type (integer 0) start))
+ (print (incf start 22))
+ (print (incf start 26)))
+ (let ((start 10))
+ (declare (type (integer 0) start))
+ (print (incf start 22))
+ (print (incf start 26))))))
+
+ This example could be solved with clever enough constraint
+ propagation or with SSA, but consider
+
+ (let ((x 0))
+ (loop (incf x 2)))
+
+ The careful type of X is {2k} :-(. Is it really important to be
+ able to work with unions of many intervals?
+
+190: "PPC/Linux pipe? buffer? bug"
+ In sbcl-0.7.6, the run-program.test.sh test script sometimes hangs
+ on the PPC/Linux platform, waiting for a zombie env process. This
+ is a classic symptom of buffer filling and deadlock, but it seems
+ only sporadically reproducible.
+
+191: "Miscellaneous PCL deficiencies"
+ (reported by Alexey Dejneka sbcl-devel 2002-08-04)
+ a. DEFCLASS does not inform the compiler about generated
+ functions. Compiling a file with
+ (DEFCLASS A-CLASS ()
+ ((A-CLASS-X)))
+ (DEFUN A-CLASS-X (A)
+ (WITH-SLOTS (A-CLASS-X) A
+ A-CLASS-X))
+ results in a STYLE-WARNING:
+ undefined-function
+ SB-SLOT-ACCESSOR-NAME::|COMMON-LISP-USER A-CLASS-X slot READER|
+
+ APD's fix for this was checked in to sbcl-0.7.6.20, but Pierre
+ Mai points out that the declamation of functions is in fact
+ incorrect in some cases (most notably for structure
+ classes). This means that at present erroneous attempts to use
+ WITH-SLOTS and the like on classes with metaclass STRUCTURE-CLASS
+ won't get the corresponding STYLE-WARNING.
+ c. (fixed in 0.8.4.23)
+
+201: "Incautious type inference from compound types"
+ a. (reported by APD sbcl-devel 2002-09-17)
+ (DEFUN FOO (X)
+ (LET ((Y (CAR (THE (CONS INTEGER *) X))))
+ (SETF (CAR X) NIL)
+ (FORMAT NIL "~S IS ~S, Y = ~S"
+ (CAR X)
+ (TYPECASE (CAR X)
+ (INTEGER 'INTEGER)
+ (T '(NOT INTEGER)))
+ Y)))
+
+ (FOO ' (1 . 2)) => "NIL IS INTEGER, Y = 1"
+
+ b.
+ * (defun foo (x)
+ (declare (type (array * (4 4)) x))
+ (let ((y x))
+ (setq x (make-array '(4 4)))
+ (adjust-array y '(3 5))
+ (= (array-dimension y 0) (eval `(array-dimension ,y 0)))))
+ FOO
+ * (foo (make-array '(4 4) :adjustable t))
+ NIL
+
+205: "environment issues in cross compiler"
+ (These bugs have no impact on user code, but should be fixed or
+ documented.)
+ a. Macroexpanders introduced with MACROLET are defined in the null
+ lexical environment.
+ b. The body of (EVAL-WHEN (:COMPILE-TOPLEVEL) ...) is evaluated in
+ the null lexical environment.
+ c. The cross-compiler cannot inline functions defined in a non-null
+ lexical environment.
+
+206: ":SB-FLUID feature broken"
+ (reported by Antonio Martinez-Shotton sbcl-devel 2002-10-07)
+ Enabling :SB-FLUID in the target-features list in sbcl-0.7.8 breaks
+ the build.
+
+207: "poorly distributed SXHASH results for compound data"
+ SBCL's SXHASH could probably try a little harder. ANSI: "the
+ intent is that an implementation should make a good-faith
+ effort to produce hash-codes that are well distributed
+ within the range of non-negative fixnums". But
+ (let ((hits (make-hash-table)))
+ (dotimes (i 16)
+ (dotimes (j 16)
+ (let* ((ij (cons i j))
+ (newlist (push ij (gethash (sxhash ij) hits))))
+ (when (cdr newlist)
+ (format t "~&collision: ~S~%" newlist))))))
+ reports lots of collisions in sbcl-0.7.8. A stronger MIX function
+ would be an obvious way of fix. Maybe it would be acceptably efficient
+ to redo MIX using a lookup into a 256-entry s-box containing
+ 29-bit pseudorandom numbers?
+
+211: "keywords processing"
+ a. :ALLOW-OTHER-KEYS T should allow a function to receive an odd
+ number of keyword arguments.
+ e. Compiling
+
+ (flet ((foo (&key y) (list y)))
+ (list (foo :y 1 :y 2)))
+
+ issues confusing message
+
+ ; in: LAMBDA NIL
+ ; (FOO :Y 1 :Y 2)
+ ;
+ ; caught STYLE-WARNING:
+ ; The variable #:G15 is defined but never used.
+
+212: "Sequence functions and circular arguments"
+ COERCE, MERGE and CONCATENATE go into an infinite loop when given
+ circular arguments; it would be good for the user if they could be
+ given an error instead (ANSI 17.1.1 allows this behaviour on the part
+ of the implementation, as conforming code cannot give non-proper
+ sequences to these functions. MAP also has this problem (and
+ solution), though arguably the convenience of being able to do
+ (MAP 'LIST '+ FOO '#1=(1 . #1#))
+ might be classed as more important (though signalling an error when
+ all of the arguments are circular is probably desireable).
+
+213: "Sequence functions and type checking"
+ a. (fixed in 0.8.4.36)
+ b. MAP, when given a type argument that is SUBTYPEP LIST, does not
+ check that it will return a sequence of the given type. Fixing
+ it along the same lines as the others (cf. work done around
+ sbcl-0.7.8.45) is possible, but doing so efficiently didn't look
+ entirely straightforward.
+ c. All of these functions will silently accept a type of the form
+ (CONS INTEGER *)
+ whether or not the return value is of this type. This is
+ probably permitted by ANSI (see "Exceptional Situations" under
+ ANSI MAKE-SEQUENCE), but the DERIVE-TYPE mechanism does not
+ know about this escape clause, so code of the form
+ (INTEGERP (CAR (MAKE-SEQUENCE '(CONS INTEGER *) 2)))
+ can erroneously return T.
+
+215: ":TEST-NOT handling by functions"
+ a. FIND and POSITION currently signal errors when given non-NIL for
+ both their :TEST and (deprecated) :TEST-NOT arguments, but by
+ ANSI 17.2 "the consequences are unspecified", which by ANSI 1.4.2
+ means that the effect is "unpredictable but harmless". It's not
+ clear what that actually means; it may preclude conforming
+ implementations from signalling errors.
+ b. COUNT, REMOVE and the like give priority to a :TEST-NOT argument
+ when conflict occurs. As a quality of implementation issue, it
+ might be preferable to treat :TEST and :TEST-NOT as being in some
+ sense the same &KEY, and effectively take the first test function in
+ the argument list.
+ c. Again, a quality of implementation issue: it would be good to issue a
+ STYLE-WARNING at compile-time for calls with :TEST-NOT, and a
+ WARNING for calls with both :TEST and :TEST-NOT; possibly this
+ latter should be WARNed about at execute-time too.
+
+216: "debugger confused by frames with invalid number of arguments"
+ In sbcl-0.7.8.51, executing e.g. (VECTOR-PUSH-EXTEND T), BACKTRACE, Q
+ leaves the system confused, enough so that (QUIT) no longer works.
+ It's as though the process of working with the uninitialized slot in
+ the bad VECTOR-PUSH-EXTEND frame causes GC problems, though that may
+ not be the actual problem. (CMU CL 18c doesn't have problems with this.)
+
+ This is probably the same bug as 162
+
+217: "Bad type operations with FUNCTION types"
+ In sbcl.0.7.7:
+
+ * (values-type-union (specifier-type '(function (base-char)))
+ (specifier-type '(function (integer))))
+
+ #<FUN-TYPE (FUNCTION (BASE-CHAR) *)>
+
+ It causes insertion of wrong type assertions into generated
+ code. E.g.
+
+ (defun foo (x s)
+ (let ((f (etypecase x
+ (character #'write-char)
+ (integer #'write-byte))))
+ (funcall f x s)
+ (etypecase x
+ (character (write-char x s))
+ (integer (write-byte x s)))))
+
+ Then (FOO #\1 *STANDARD-OUTPUT*) signals type error.
+
+ (In 0.7.9.1 the result type is (FUNCTION * *), so Python does not
+ produce invalid code, but type checking is not accurate.)
+
+233: bugs in constraint propagation
+ b.
+ (declaim (optimize (speed 2) (safety 3)))
+ (defun foo (x y)
+ (if (typep (prog1 x (setq x y)) 'double-float)
+ (+ x 1d0)
+ (+ x 2)))
+ (foo 1d0 5) => segmentation violation
+
+235: "type system and inline expansion"
+ a.
+ (declaim (ftype (function (cons) number) acc))
+ (declaim (inline acc))
+ (defun acc (c)
+ (the number (car c)))
+
+ (defun foo (x y)
+ (values (locally (declare (optimize (safety 0)))
+ (acc x))
+ (locally (declare (optimize (safety 3)))
+ (acc y))))
+
+ (foo '(nil) '(t)) => NIL, T.
+
+237: "Environment arguments to type functions"
+ a. Functions SUBTYPEP, TYPEP, UPGRADED-ARRAY-ELEMENT-TYPE, and
+ UPGRADED-COMPLEX-PART-TYPE now have an optional environment
+ argument, but they ignore it completely. This is almost
+ certainly not correct.
+ b. Also, the compiler's optimizers for TYPEP have not been informed
+ about the new argument; consequently, they will not transform
+ calls of the form (TYPEP 1 'INTEGER NIL), even though this is
+ just as optimizeable as (TYPEP 1 'INTEGER).
+
+238: "REPL compiler overenthusiasm for CLOS code"
+ From the REPL,
+ * (defclass foo () ())
+ * (defmethod bar ((x foo) (foo foo)) (call-next-method))
+ causes approximately 100 lines of code deletion notes. Some
+ discussion on this issue happened under the title 'Three "interesting"
+ bugs in PCL', resulting in a fix for this oververbosity from the
+ compiler proper; however, the problem persists in the interactor
+ because the notion of original source is not preserved: for the
+ compiler, the original source of the above expression is (DEFMETHOD
+ BAR ((X FOO) (FOO FOO)) (CALL-NEXT-METHOD)), while by the time the
+ compiler gets its hands on the code needing compilation from the REPL,
+ it has been macroexpanded several times.
+
+ A symptom of the same underlying problem, reported by Tony Martinez:
+ * (handler-case
+ (with-input-from-string (*query-io* " no")
+ (yes-or-no-p))
+ (simple-type-error () 'error))
+ ; in: LAMBDA NIL
+ ; (SB-KERNEL:FLOAT-WAIT)
+ ;
+ ; note: deleting unreachable code
+ ; compilation unit finished
+ ; printed 1 note
+
+241: "DEFCLASS mysteriously remembers uninterned accessor names."
+ (from tonyms on #lisp IRC 2003-02-25)
+ In sbcl-0.7.12.55, typing
+ (defclass foo () ((bar :accessor foo-bar)))
+ (profile foo-bar)
+ (unintern 'foo-bar)
+ (defclass foo () ((bar :accessor foo-bar)))
+ gives the error message
+ "#:FOO-BAR already names an ordinary function or a macro."
+ So it's somehow checking the uninterned old accessor name instead
+ of the new requested accessor name, which seems broken to me (WHN).
+
+242: "WRITE-SEQUENCE suboptimality"
+ (observed from clx performance)
+ In sbcl-0.7.13, WRITE-SEQUENCE of a sequence of type
+ (SIMPLE-ARRAY (UNSIGNED-BYTE 8) (*)) on a stream with element-type
+ (UNSIGNED-BYTE 8) will write to the stream one byte at a time,
+ rather than writing the sequence in one go, leading to severe
+ performance degradation.
+
+243: "STYLE-WARNING overenthusiasm for unused variables"
+ (observed from clx compilation)
+ In sbcl-0.7.14, in the presence of the macros
+ (DEFMACRO FOO (X) `(BAR ,X))
+ (DEFMACRO BAR (X) (DECLARE (IGNORABLE X)) 'NIL)
+ somewhat surprising style warnings are emitted for
+ (COMPILE NIL '(LAMBDA (Y) (FOO Y))):
+ ; in: LAMBDA (Y)
+ ; (LAMBDA (Y) (FOO Y))
+ ;
+ ; caught STYLE-WARNING:
+ ; The variable Y is defined but never used.
+
+245: bugs in disassembler
+ a. On X86 an immediate operand for IMUL is printed incorrectly.
+ b. On X86 operand size prefix is not recognized.
+
+251:
+ (defun foo (&key (a :x))
+ (declare (fixnum a))
+ a)
+
+ does not cause a warning. (BTW: old SBCL issued a warning, but for a
+ function, which was never called!)
+
+256:
+ Compiler does not emit warnings for
+
+ a. (lambda () (svref (make-array 8 :adjustable t) 1))
+
+ b. (lambda (x)
+ (list (let ((y (the real x)))
+ (unless (floatp y) (error ""))
+ y)
+ (integer-length x)))
+
+ c. (lambda (x)
+ (declare (optimize (debug 0)))
+ (declare (type vector x))
+ (list (fill-pointer x)
+ (svref x 1)))
+
+257:
+ Complex array type does not have corresponding type specifier.
+
+ This is a problem because the compiler emits optimization notes when
+ you use a non-simple array, and without a type specifier for hairy
+ array types, there's no good way to tell it you're doing it
+ intentionally so that it should shut up and just compile the code.
+
+ Another problem is confusing error message "asserted type ARRAY
+ conflicts with derived type (VALUES SIMPLE-VECTOR &OPTIONAL)" during
+ compiling (LAMBDA (V) (VALUES (SVREF V 0) (VECTOR-POP V))).
+
+ The last problem is that when type assertions are converted to type
+ checks, types are represented with type specifiers, so we could lose
+ complex attribute. (Now this is probably not important, because
+ currently checks for complex arrays seem to be performed by
+ callees.)
+
+259:
+ (compile nil '(lambda () (aref (make-array 0) 0))) compiles without
+ warning. Analogous cases with the index and length being equal and
+ greater than 0 are warned for; the problem here seems to be that the
+ type required for an array reference of this type is (INTEGER 0 (0))
+ which is canonicalized to NIL.
+
+260:
+ a.
+ (let* ((s (gensym))
+ (t1 (specifier-type s)))
+ (eval `(defstruct ,s))
+ (type= t1 (specifier-type s)))
+ => NIL, NIL
+
+ (fixed in 0.8.1.24)
+
+ b. The same for CSUBTYPEP.
+
+262: "yet another bug in inline expansion of local functions"
+ Compiler fails on
+
+ (defun foo (x y)
+ (declare (integer x y))
+ (+ (block nil
+ (flet ((xyz (u)
+ (declare (integer u))
+ (if (> (1+ (the unsigned-byte u)) 0)
+ (+ 1 u)
+ (return (+ 38 (cos (/ u 78)))))))
+ (declare (inline xyz))
+ (return-from foo
+ (* (funcall (eval #'xyz) x)
+ (if (> x 30)
+ (funcall (if (> x 5) #'xyz #'identity)
+ (+ x 13))
+ 38)))))
+ (sin (* x y))))
+
+ Urgh... It's time to write IR1-copier.
+
+266:
+ David Lichteblau provided (sbcl-devel 2003-06-01) a patch to fix
+ behaviour of streams with element-type (SIGNED-BYTE 8). The patch
+ looks reasonable, if not obviously correct; however, it caused the
+ PPC/Linux port to segfault during warm-init while loading
+ src/pcl/std-class.fasl. A workaround patch was made, but it would
+ be nice to understand why the first patch caused problems, and to
+ fix the cause if possible.
+
+268: "wrong free declaration scope"
+ The following code must signal type error:
+
+ (locally (declare (optimize (safety 3)))
+ (flet ((foo (x &optional (y (car x)))
+ (declare (optimize (safety 0)))
+ (list x y)))
+ (funcall (eval #'foo) 1)))
+
+269:
+ SCALE-FLOAT should accept any integer for its second argument.
+
+270:
+ In the following function constraint propagator optimizes nothing:
+
+ (defun foo (x)
+ (declare (integer x))
+ (declare (optimize speed))
+ (typecase x
+ (fixnum "hala")
+ (fixnum "buba")
+ (bignum "hip")
+ (t "zuz")))
+
+273:
+ Compilation of the following two forms causes "X is unbound" error:
+
+ (symbol-macrolet ((x pi))
+ (macrolet ((foo (y) (+ x y)))
+ (declaim (inline bar))
+ (defun bar (z)
+ (* z (foo 4)))))
+ (defun quux (z)
+ (bar z))
+
+ (See (COERCE (CDR X) 'FUNCTION) in IR1-CONVERT-INLINE-LAMBDA.)
+
+274:
+ CLHS says that type declaration of a symbol macro should not affect
+ its expansion, but in SBCL it does. (If you like magic and want to
+ fix it, don't forget to change all uses of MACROEXPAND to
+ MACROEXPAND*.)
+
+275:
+ The following code (taken from CLOCC) takes a lot of time to compile:
+
+ (defun foo (n)
+ (declare (type (integer 0 #.large-constant) n))
+ (expt 1/10 n))
+
+ (fixed in 0.8.2.51, but a test case would be good)
+
+276:
+ (defmethod fee ((x fixnum))
+ (setq x (/ x 2))
+ x)
+ (fee 1) => type error
+
+ (taken from CLOCC)
+
+278:
+ a.
+ (defun foo ()
+ (declare (optimize speed))
+ (loop for i of-type (integer 0) from 0 by 2 below 10
+ collect i))
+
+ uses generic arithmetic.
+
+ b. (fixed in 0.8.3.6)
+
+279: type propagation error -- correctly inferred type goes astray?
+ In sbcl-0.8.3 and sbcl-0.8.1.47, the warning
+ The binding of ABS-FOO is a (VALUES (INTEGER 0 0)
+ &OPTIONAL), not a (INTEGER 1 536870911)
+ is emitted when compiling this file:
+ (declaim (ftype (function ((integer 0 #.most-positive-fixnum))
+ (integer #.most-negative-fixnum 0))
+ foo))
+ (defun foo (x)
+ (- x))
+ (defun bar (x)
+ (let* (;; Uncomment this for a type mismatch warning indicating
+ ;; that the type of (FOO X) is correctly understood.
+ #+nil (fs-foo (float-sign (foo x)))
+ ;; Uncomment this for a type mismatch warning
+ ;; indicating that the type of (ABS (FOO X)) is
+ ;; correctly understood.
+ #+nil (fs-abs-foo (float-sign (abs (foo x))))
+ ;; something wrong with this one though
+ (abs-foo (abs (foo x))))
+ (declare (type (integer 1 100) abs-foo))
+ (print abs-foo)))
+
+ (see also bug 117)
+
+280: bogus WARNING about duplicate function definition
+ In sbcl-0.8.3 and sbcl-0.8.1.47, if BS.MIN is defined inline,
+ e.g. by
+ (declaim (inline bs.min))
+ (defun bs.min (bases) nil)
+ before compiling the file below, the compiler warns
+ Duplicate definition for BS.MIN found in one static
+ unit (usually a file).
+ when compiling
+ (declaim (special *minus* *plus* *stagnant*))
+ (defun b.*.min (&optional (x () xp) (y () yp) &rest rest)
+ (bs.min avec))
+ (define-compiler-macro b.*.min (&rest rest)
+ `(bs.min ,@rest))
+ (defun afish-d-rbd (pd)
+ (if *stagnant*
+ (b.*.min (foo-d-rbd *stagnant*))
+ (multiple-value-bind (reduce-fn initial-value)
+ (etypecase pd
+ (list (values #'bs.min 0))
+ (vector (values #'bs.min *plus*)))
+ (let ((cv-ks (cv (kpd.ks pd))))
+ (funcall reduce-fn d-rbds)))))
+ (defun bfish-d-rbd (pd)
+ (if *stagnant*
+ (b.*.min (foo-d-rbd *stagnant*))
+ (multiple-value-bind (reduce-fn initial-value)
+ (etypecase pd
+ (list (values #'bs.min *minus*))
+ (vector (values #'bs.min 0)))
+ (let ((cv-ks (cv (kpd.ks pd))))
+ (funcall reduce-fn d-rbds)))))
+
+281: COMPUTE-EFFECTIVE-METHOD error signalling.
+ (slightly obscured by a non-0 default value for
+ SB-PCL::*MAX-EMF-PRECOMPUTE-METHODS*)
+ It would be natural for COMPUTE-EFFECTIVE-METHOD to signal errors
+ when it finds a method with invalid qualifiers. However, it
+ shouldn't signal errors when any such methods are not applicable to
+ the particular call being evaluated, and certainly it shouldn't when
+ simply precomputing effective methods that may never be called.
+ (setf sb-pcl::*max-emf-precompute-methods* 0)
+ (defgeneric foo (x)
+ (:method-combination +)
+ (:method ((x symbol)) 1)
+ (:method + ((x number)) x))
+ (foo 1) -> ERROR, but should simply return 1
+
+ The issue seems to be that construction of a discriminating function
+ calls COMPUTE-EFFECTIVE-METHOD with methods that are not all applicable.
+
+283: Thread safety: libc functions
+ There are places that we call unsafe-for-threading libc functions
+ that we should find alternatives for, or put locks around. Known or
+ strongly suspected problems, as of 0.8.3.10: please update this
+ bug instead of creating new ones
+
+ localtime() - called for timezone calculations in code/time.lisp
+
+284: Thread safety: special variables
+ There are lots of special variables in SBCL, and I feel sure that at
+ least some of them are indicative of potentially thread-unsafe
+ parts of the system. See doc/internals/notes/threading-specials
+
+286: "recursive known functions"
+ Self-call recognition conflicts with known function
+ recognition. Currently cross compiler and target COMPILE do not
+ recognize recursion, and in target compiler it can be disabled. We
+ can always disable it for known functions with RECURSIVE attribute,
+ but there remains a possibility of a function with a
+ (tail)-recursive simplification pass and transforms/VOPs for base
+ cases.
+
+287: PPC/Linux miscompilation or corruption in first GC
+ When the runtime is compiled with -O3 on certain PPC/Linux machines, a
+ segmentation fault is reported at the point of first triggered GC,
+ during the compilation of DEFSTRUCT WRAPPER. As a temporary workaround,
+ the runtime is no longer compiled with -O3 on PPC/Linux, but it is likely
+ that this merely obscures, not solves, the underlying problem; as and when
+ underlying problems are fixed, it would be worth trying again to provoke
+ this problem.
+
+288: fundamental cross-compilation issues (from old UGLINESS file)
+ Using host floating point numbers to represent target floating point
+ numbers, or host characters to represent target characters, is
+ theoretically shaky. (The characters are OK as long as the characters
+ are in the ANSI-guaranteed character set, though, so they aren't a
+ real problem as long as the sources don't need anything but that;
+ the floats are a real problem.)
+
+289: "type checking and source-transforms"
+ a.
+ (block nil (let () (funcall #'+ (eval 'nil) (eval '1) (return :good))))
+ signals type error.
+
+ Our policy is to check argument types at the moment of a call. It
+ disagrees with ANSI, which says that type assertions are put
+ immediately onto argument expressions, but is easier to implement in
+ IR1 and is more compatible to type inference, inline expansion,
+ etc. IR1-transforms automatically keep this policy, but source
+ transforms for associative functions (such as +), being applied
+ during IR1-convertion, do not. It may be tolerable for direct calls
+ (+ x y z), but for (FUNCALL #'+ x y z) it is non-conformant.
+
+ b. Another aspect of this problem is efficiency. [x y + z +]
+ requires less registers than [x y z + +]. This transformation is
+ currently performed with source transforms, but it would be good to
+ also perform it in IR1 optimization phase.
+
+290: Alpha floating point and denormalized traps
+ In SBCL 0.8.3.6x on the alpha, we work around what appears to be a
+ hardware or kernel deficiency: the status of the enable/disable
+ denormalized-float traps bit seems to be ambiguous; by the time we
+ get to os_restore_fp_control after a trap, denormalized traps seem
+ to be enabled. Since we don't want a trap every time someone uses a
+ denormalized float, in general, we mask out that bit when we restore
+ the control word; however, this clobbers any change the user might
+ have made.
+
+296:
+ (reported by Adam Warner, sbcl-devel 2003-09-23)
+
+ The --load toplevel argument does not perform any sanitization of its
+ argument. As a result, files with Lisp pathname pattern characters
+ (#\* or #\?, for instance) or quotation marks can cause the system
+ to perform arbitrary behaviour.
+
+297:
+ LOOP with non-constant arithmetic step clauses suffers from overzealous
+ type constraint: code of the form
+ (loop for d of-type double-float from 0d0 to 10d0 by x collect d)
+ compiles to a type restriction on X of (AND DOUBLE-FLOAT (REAL
+ (0))). However, an integral value of X should be legal, because
+ successive adds of integers to double-floats produces double-floats,
+ so none of the type restrictions in the code is violated.