+ (see also bug 279)
+
+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.)
+
+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.
+
+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.)
+
+ [ partially fixed by CSR in 0.8.17.17 because of a PFD ansi-tests
+ report that (COMPLEX RATIO) was failing; still failing on types of
+ the form (AND NUMBER (SATISFIES REALP) (SATISFIES ZEROP)). ]
+
+ 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
+
+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?
+
+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.
+
+ [much later, in 2006-08] in fact it's no longer erroneous to use
+ WITH-SLOTS on structure-classes. However, including :METACLASS
+ STRUCTURE-CLASS in the class definition gives a whole bunch of
+ function redefinition warnings, so we're still not good to close
+ this bug...
+
+ 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.
+
+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"
+ 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
+
+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.
+
+ As of 0.9.15.41 this seems to be due to ACC being inlined only once
+ inside FOO, which results in the second call reusing the FUNCTIONAL
+ resulting from the first -- which doesn't check the type.
+
+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
+
+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.
+ As of sbcl-0.9.0.36, this is solved for fd-streams, so is less of a
+ problem in practice. (Fully fixing this would require adding a
+ ansi-stream-n-bout slot and associated methods to write a byte
+ sequence to ansi-stream, similar to the existing ansi-stream-sout
+ slot/functions.)
+
+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
+ 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. (fixed at some point before 1.0.4.10)
+
+ 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"
+ During inline expansion of a local function Python can try to
+ reference optimized away objects (functions, variables, CTRANs from
+ tags and blocks), which later may lead to problems. Some of the
+ cases are worked around by forbidding expansion in such cases, but
+ the better way would be to reimplement inline expansion by copying
+ IR1 structures.
+
+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)))
+
+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:
+ b. The same as in a., but using MULTIPLE-VALUE-SETQ instead of SETQ.
+ c. (defvar *faa*)
+ (defmethod faa ((*faa* double-float))
+ (set '*faa* (when (< *faa* 0) (- *faa*)))
+ (1+ *faa*))
+ (faa 1d0) => type error
+
+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)
+
+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 1.0.3.13: please update this
+ bug instead of creating new ones
+
+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.
+
+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.
+
+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.
+
+300: (reported by Peter Graves) Function PEEK-CHAR checks PEEK-TYPE
+ argument type only after having read a character. This is caused
+ with EXPLICIT-CHECK attribute in DEFKNOWN. The similar problem
+ exists with =, /=, <, >, <=, >=. They were fixed, but it is probably
+ less error prone to have EXPLICIT-CHECK be a local declaration,
+ being put into the definition, instead of an attribute being kept in
+ a separate file; maybe also put it into SB-EXT?
+
+301: ARRAY-SIMPLE-=-TYPE-METHOD breaks on corner cases which can arise
+ in NOTE-ASSUMED-TYPES
+ In sbcl-0.8.7.32, compiling the file
+ (defun foo (x y)
+ (declare (type integer x))
+ (declare (type (vector (or hash-table bit)) y))
+ (bletch 2 y))
+ (defun bar (x y)
+ (declare (type integer x))
+ (declare (type (simple-array base (2)) y))
+ (bletch 1 y))
+ gives the error
+ failed AVER: "(NOT (AND (NOT EQUALP) CERTAINP))"
+
+303: "nonlinear LVARs" (aka MISC.293)
+ (defun buu (x)
+ (multiple-value-call #'list
+ (block foo
+ (multiple-value-prog1
+ (eval '(values :a :b :c))
+ (catch 'bar
+ (if (> x 0)
+ (return-from foo
+ (eval `(if (> ,x 1)
+ 1
+ (throw 'bar (values 3 4)))))))))))
+
+ (BUU 1) returns garbage.
+
+ The problem is that both EVALs sequentially write to the same LVAR.
+
+306: "Imprecise unions of array types"
+
+ a. fixed in SBCL 0.9.15.48
+
+ b.(subtypep
+ 'array
+ `(or
+ ,@(loop for x across sb-vm:*specialized-array-element-type-properties*
+ collect `(array ,(sb-vm:saetp-specifier x)))))
+ => NIL, T (when it should be T, T)
+
+309: "Dubious values for implementation limits"
+ (reported by Bruno Haible sbcl-devel "Incorrect value of
+ multiple-values-limit" 2004-04-19)
+ (values-list (make-list 1000000)), on x86/linux, signals a stack
+ exhaustion condition, despite MULTIPLE-VALUES-LIMIT being
+ significantly larger than 1000000. There are probably similar
+ dubious values for CALL-ARGUMENTS-LIMIT (see cmucl-help/cmucl-imp
+ around the same time regarding a call to LIST on sparc with 1000
+ arguments) and other implementation limit constants.
+
+314: "LOOP :INITIALLY clauses and scope of initializers"
+ reported by Bruno Haible sbcl-devel "various SBCL bugs" from CLISP
+ test suite, originally by Thomas F. Burdick.
+ ;; <http://www.lisp.org/HyperSpec/Body/sec_6-1-7-2.html>
+ ;; According to the HyperSpec 6.1.2.1.4, in for-as-equals-then, var is
+ ;; initialized to the result of evaluating form1. 6.1.7.2 says that
+ ;; initially clauses are evaluated in the loop prologue, which precedes all
+ ;; loop code except for the initial settings provided by with, for, or as.
+ (loop :for x = 0 :then (1+ x)
+ :for y = (1+ x) :then (ash y 1)
+ :for z :across #(1 3 9 27 81 243)
+ :for w = (+ x y z)
+ :initially (assert (zerop x)) :initially (assert (= 2 w))
+ :until (>= w 100) :collect w)
+ Expected: (2 6 15 38)
+ Got: ERROR
+
+318: "stack overflow in compiler warning with redefined class"
+ reported by Bruno Haible sbcl-devel "various SBCL bugs" from CLISP
+ test suite.
+ (defstruct foo a)
+ (setf (find-class 'foo) nil)
+ (defstruct foo slot-1)
+ This used to give a stack overflow from within the printer, which has
+ been fixed as of 0.8.16.11. Current result:
+ ; caught ERROR:
+ ; can't compile TYPEP of anonymous or undefined class:
+ ; #<SB-KERNEL:STRUCTURE-CLASSOID FOO>
+ ...
+ debugger invoked on a TYPE-ERROR in thread 19973:
+ The value NIL is not of type FUNCTION.
+
+ CSR notes: it's not really clear what it should give: is (SETF FIND-CLASS)
+ meant to be enough to delete structure classes from the system?
+
+319: "backquote with comma inside array"
+ reported by Bruno Haible sbcl-devel "various SBCL bugs" from CLISP
+ test suite.
+ (read-from-string "`#1A(1 2 ,(+ 2 2) 4)")
+ gives
+ #(1 2 ((SB-IMPL::|,|) + 2 2) 4)
+ which probably isn't intentional.
+
+324: "STREAMs and :ELEMENT-TYPE with large bytesize"
+ In theory, (open foo :element-type '(unsigned-byte <x>)) should work
+ for all positive integral <x>. At present, it only works for <x> up
+ to about 1024 (and similarly for signed-byte), so
+ (open "/dev/zero" :element-type '(unsigned-byte 1025))
+ gives an error in sbcl-0.8.10.
+
+325: "CLOSE :ABORT T on supeseding streams"
+ Closing a stream opened with :IF-EXISTS :SUPERSEDE with :ABORT T leaves no
+ file on disk, even if one existed before opening.
+
+ The illegality of this is not crystal clear, as the ANSI dictionary
+ entry for CLOSE says that when :ABORT is T superseded files are not
+ superseded (ie. the original should be restored), whereas the OPEN
+ entry says about :IF-EXISTS :SUPERSEDE "If possible, the
+ implementation should not destroy the old file until the new stream
+ is closed." -- implying that even though undesirable, early deletion
+ is legal. Restoring the original would none the less be the polite
+ thing to do.
+
+326: "*PRINT-CIRCLE* crosstalk between streams"
+ In sbcl-0.8.10.48 it's possible for *PRINT-CIRCLE* references to be
+ mixed between streams when output operations are intermingled closely
+ enough (as by doing output on S2 from within (PRINT-OBJECT X S1) in the
+ test case below), so that e.g. the references #2# appears on a stream
+ with no preceding #2= on that stream to define it (because the #2= was
+ sent to another stream).
+ (cl:in-package :cl-user)
+ (defstruct foo index)
+ (defparameter *foo* (make-foo :index 4))
+ (defstruct bar)
+ (defparameter *bar* (make-bar))
+ (defparameter *tangle* (list *foo* *bar* *foo*))
+ (defmethod print-object ((foo foo) stream)
+ (let ((index (foo-index foo)))
+ (format *trace-output*
+ "~&-$- emitting FOO ~D, ambient *BAR*=~S~%"
+ index *bar*)
+ (format stream "[FOO ~D]" index))
+ foo)
+ (let ((tsos (make-string-output-stream))
+ (ssos (make-string-output-stream)))
+ (let ((*print-circle* t)
+ (*trace-output* tsos)
+ (*standard-output* ssos))
+ (prin1 *tangle* *standard-output*))
+ (let ((string (get-output-stream-string ssos)))
+ (unless (string= string "(#1=[FOO 4] #S(BAR) #1#)")
+ ;; In sbcl-0.8.10.48 STRING was "(#1=[FOO 4] #2# #1#)".:-(
+ (error "oops: ~S" string)))))
+ It might be straightforward to fix this by turning the
+ *CIRCULARITY-HASH-TABLE* and *CIRCULARITY-COUNTER* variables into
+ per-stream slots, but (1) it would probably be sort of messy faking
+ up the special variable binding semantics using UNWIND-PROTECT and
+ (2) it might be sort of a pain to test that no other bugs had been
+ introduced.
+
+328: "Profiling generic functions", transplanted from #241
+ (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."
+
+ Problem: when a generic function is profiled, it appears as an ordinary
+ function to PCL. (Remembering the uninterned accessor is OK, as the
+ redefinition must be able to remove old accessors from their generic
+ functions.)
+
+329: "Sequential class redefinition"
+ reported by Bruno Haible:
+ (defclass reactor () ((max-temp :initform 10000000)))
+ (defvar *r1* (make-instance 'reactor))
+ (defvar *r2* (make-instance 'reactor))
+ (slot-value *r1* 'max-temp)
+ (slot-value *r2* 'max-temp)
+ (defclass reactor () ((uptime :initform 0)))
+ (slot-value *r1* 'uptime)
+ (defclass reactor () ((uptime :initform 0) (max-temp :initform 10000)))
+ (slot-value *r1* 'max-temp) ; => 10000
+ (slot-value *r2* 'max-temp) ; => 10000000 oops...
+
+ Possible solution:
+ The method effective when the wrapper is obsoleted can be saved
+ in the wrapper, and then to update the instance just run through
+ all the old wrappers in order from oldest to newest.
+
+332: "fasl stack inconsistency in structure redefinition"
+ (reported by Tim Daly Jr sbcl-devel 2004-05-06)
+ Even though structure redefinition is undefined by the standard, the
+ following behaviour is suboptimal: running
+ (defun stimulate-sbcl ()
+ (let ((filename (format nil "/tmp/~A.lisp" (gensym))))
+ ;;create a file which redefines a structure incompatibly
+ (with-open-file (f filename :direction :output :if-exists :supersede)
+ (print '(defstruct astruct foo) f)
+ (print '(defstruct astruct foo bar) f))
+ ;;compile and load the file, then invoke the continue restart on
+ ;;the structure redefinition error
+ (handler-bind ((error (lambda (c) (continue c))))
+ (load (compile-file filename)))))
+ (stimulate-sbcl)
+ and choosing the CONTINUE restart yields the message
+ debugger invoked on a SB-INT:BUG in thread 27726:
+ fasl stack not empty when it should be
+
+336: "slot-definitions must retain the generic functions of accessors"
+ reported by Tony Martinez:
+ (defclass foo () ((bar :reader foo-bar)))
+ (defun foo-bar (x) x)
+ (defclass foo () ((bar :reader get-bar))) ; => error, should work
+
+ Note: just punting the accessor removal if the fdefinition
+ is not a generic function is not enough:
+
+ (defclass foo () ((bar :reader foo-bar)))
+ (defvar *reader* #'foo-bar)
+ (defun foo-bar (x) x)
+ (defclass foo () ((bar :initform 'ok :reader get-bar)))
+ (funcall *reader* (make-instance 'foo)) ; should be an error, since
+ ; the method must be removed
+ ; by the class redefinition
+
+ Fixing this should also fix a subset of #328 -- update the
+ description with a new test-case then.
+
+339: "DEFINE-METHOD-COMBINATION bugs"
+ (reported by Bruno Haible via the clisp test suite)
+
+ a. Syntax checking laxity (should produce errors):
+ i. (define-method-combination foo :documentation :operator)
+ ii. (define-method-combination foo :documentation nil)
+ iii. (define-method-combination foo nil)
+ iv. (define-method-combination foo nil nil
+ (:arguments order &aux &key))
+ v. (define-method-combination foo nil nil (:arguments &whole))
+ vi. (define-method-combination foo nil nil (:generic-function))
+ vii. (define-method-combination foo nil nil (:generic-function bar baz))
+ viii. (define-method-combination foo nil nil (:generic-function (bar)))
+ ix. (define-method-combination foo nil ((3)))
+ x. (define-method-combination foo nil ((a)))
+
+ b. define-method-combination arguments lambda list badness
+ i. &aux args are currently unsupported;
+ ii. default values of &optional and &key arguments are ignored;
+ iii. supplied-p variables for &optional and &key arguments are not
+ bound.
+
+ c. (fixed in sbcl-0.9.15.15)
+
+344: more (?) ROOM T problems (possibly part of bug 108)
+ In sbcl-0.8.12.51, and off and on leading up to it, the
+ SB!VM:MEMORY-USAGE operations in ROOM T caused
+ unhandled condition (of type SB-INT:BUG):
+ failed AVER: "(SAP= CURRENT END)"
+ Several clever people have taken a shot at this without fixing
+ it; this time around (before sbcl-0.8.13 release) I (WHN) just
+ commented out the SB!VM:MEMORY-USAGE calls until someone figures
+ out how to make them work reliably with the rest of the GC.
+
+ (Note: there's at least one dubious thing in room.lisp: see the
+ comment in VALID-OBJ)
+
+346: alpha backtrace
+ In sbcl-0.8.13, all backtraces from errors caused by internal errors
+ on the alpha seem to have a "bogus stack frame".
+
+349: PPRINT-INDENT rounding implementation decisions
+ At present, pprint-indent (and indeed the whole pretty printer)
+ more-or-less assumes that it's using a monospace font. That's
+ probably not too silly an assumption, but one piece of information
+ the current implementation loses is from requests to indent by a
+ non-integral amount. As of sbcl-0.8.15.9, the system silently
+ truncates the indentation to an integer at the point of request, but
+ maybe the non-integral value should be propagated through the
+ pprinter and only truncated at output? (So that indenting by 1/2
+ then 3/2 would indent by two spaces, not one?)
+
+352: forward-referenced-class trouble
+ reported by Bruno Haible on sbcl-devel
+ (defclass c (a) ())
+ (setf (class-name (find-class 'a)) 'b)
+ (defclass a () (x))
+ (defclass b () (y))
+ (make-instance 'c)
+ Expected: an instance of c, with a slot named x
+ Got: debugger invoked on a SIMPLE-ERROR in thread 78906:
+ While computing the class precedence list of the class named C.
+ The class named B is a forward referenced class.
+ The class named B is a direct superclass of the class named C.
+
+ [ Is this actually a bug? DEFCLASS only replaces an existing class
+ when the class name is the proper name of that class, and in the
+ above code the class found by (FIND-CLASS 'A) does not have a
+ proper name. CSR, 2006-08-07 ]
+
+353: debugger suboptimalities on x86
+ On x86 backtraces for undefined functions start with a bogus stack
+ frame, and backtraces for throws to unknown catch tags with a "no
+ debug information" frame. These are both due to CODE-COMPONENT-FROM-BITS
+ (used on non-x86 platforms) being a more complete solution then what
+ is done on x86.
+
+ On x86/linux large portions of tests/debug.impure.lisp have been commented
+ out as failures. The probable culprit for these problems is in x86-call-context
+ (things work fine on x86/freebsd).
+
+ More generally, the debugger internals suffer from excessive x86/non-x86
+ conditionalization and OAOOMization: refactoring the common parts would
+ be good.
+
+354: XEPs in backtraces
+ Under default compilation policy
+ (defun test ()
+ (throw :unknown t))
+ (test)
+ Has the XEP for TEST in the backtrace, not the TEST frame itself.
+ (sparc and x86 at least)
+
+ Since SBCL 0.8.20.1 this is hidden unless *SHOW-ENTRY-POINT-DETAILS*
+ is true (instead there appear two TEST frames at least on ppc). The
+ underlying cause seems to be that SB-C::TAIL-ANNOTATE will not merge
+ the tail-call for the XEP, since Python has by that time proved that
+ the function can never return; same happens if the function holds an
+ unconditional call to ERROR.
+
+356: PCL corruption
+ (reported by Bruno Haible)
+ After the "layout depth conflict" error, the CLOS is left in a state where
+ it's not possible to define new standard-class subclasses any more.
+ Test case:
+ (defclass prioritized-dispatcher ()
+ ((dependents :type list :initform nil)))
+ (defmethod sb-pcl:validate-superclass ((c1 sb-pcl:funcallable-standard-class)
+ (c2 (eql (find-class 'prioritized-dispatcher))))
+ t)
+ (defclass prioritized-generic-function (prioritized-dispatcher standard-generic-function)
+ ()
+ (:metaclass sb-pcl:funcallable-standard-class))
+ ;; ERROR, Quit the debugger with ABORT
+ (defclass typechecking-reader-class (standard-class)
+ ())
+ Expected: #<STANDARD-CLASS TYPECHECKING-READER-CLASS>
+ Got: ERROR "The assertion SB-PCL::WRAPPERS failed."
+
+ [ This test case does not cause the error any more. However,
+ similar problems can be observed with
+
+ (defclass foo (standard-class) ()
+ (:metaclass sb-mop:funcallable-standard-class))
+ (sb-mop:finalize-inheritance (find-class 'foo))
+ ;; ERROR, ABORT
+ (defclass bar (standard-class) ())
+ (make-instance 'bar)
+ ]
+
+357: defstruct inheritance of initforms
+ (reported by Bruno Haible)
+ When defstruct and defclass (with :metaclass structure-class) are mixed,
+ 1. some slot initforms are ignored by the DEFSTRUCT generated constructor
+ function, and
+ 2. all slot initforms are ignored by MAKE-INSTANCE. (This can be arguably
+ OK for initforms that were given in a DEFSTRUCT form, but for those
+ given in a DEFCLASS form, I think it qualifies as a bug.)
+ Test case:
+ (defstruct structure02a
+ slot1
+ (slot2 t)
+ (slot3 (floor pi)))
+ (defclass structure02b (structure02a)
+ ((slot4 :initform -44)
+ (slot5)
+ (slot6 :initform t)
+ (slot7 :initform (floor (* pi pi)))
+ (slot8 :initform 88))
+ (:metaclass structure-class))
+ (defstruct (structure02c (:include structure02b (slot8 -88)))
+ slot9
+ (slot10 t)
+ (slot11 (floor (exp 3))))
+ ;; 1. Form:
+ (let ((a (make-structure02c)))
+ (list (structure02c-slot4 a)
+ (structure02c-slot5 a)
+ (structure02c-slot6 a)
+ (structure02c-slot7 a)))
+ Expected: (-44 nil t 9)
+ Got: (SB-PCL::..SLOT-UNBOUND.. SB-PCL::..SLOT-UNBOUND..
+ SB-PCL::..SLOT-UNBOUND.. SB-PCL::..SLOT-UNBOUND..)
+ ;; 2. Form:
+ (let ((b (make-instance 'structure02c)))
+ (list (structure02c-slot2 b)
+ (structure02c-slot3 b)
+ (structure02c-slot4 b)
+ (structure02c-slot6 b)
+ (structure02c-slot7 b)
+ (structure02c-slot8 b)
+ (structure02c-slot10 b)
+ (structure02c-slot11 b)))
+ Expected: (t 3 -44 t 9 -88 t 20)
+ Got: (0 0 0 0 0 0 0 0)
+
+359: wrong default value for ensure-generic-function's :generic-function-class argument
+ (reported by Bruno Haible)
+ ANSI CL is silent on this, but the MOP's specification of ENSURE-GENERIC-FUNCTION says:
+ "The remaining arguments are the complete set of keyword arguments
+ received by ENSURE-GENERIC-FUNCTION."
+ and the spec of ENSURE-GENERIC-FUNCTION-USING-CLASS:
+ ":GENERIC-FUNCTION-CLASS - a class metaobject or a class name. If it is not
+ supplied, it defaults to the class named STANDARD-GENERIC-FUNCTION."
+ This is not the case in SBCL. Test case:
+ (defclass my-generic-function (standard-generic-function)
+ ()
+ (:metaclass sb-pcl:funcallable-standard-class))
+ (setf (fdefinition 'foo1)
+ (make-instance 'my-generic-function :name 'foo1))
+ (ensure-generic-function 'foo1
+ :generic-function-class (find-class 'standard-generic-function))
+ (class-of #'foo1)
+ ; => #<SB-MOP:FUNCALLABLE-STANDARD-CLASS STANDARD-GENERIC-FUNCTION>
+ (setf (fdefinition 'foo2)
+ (make-instance 'my-generic-function :name 'foo2))
+ (ensure-generic-function 'foo2)
+ (class-of #'foo2)
+ Expected: #<SB-MOP:FUNCALLABLE-STANDARD-CLASS STANDARD-GENERIC-FUNCTION>
+ Got: #<SB-MOP:FUNCALLABLE-STANDARD-CLASS MY-GENERIC-FUNCTION>
+
+362: missing error when a slot-definition is created without a name
+ (reported by Bruno Haible)
+ The MOP says about slot-definition initialization:
+ "The :NAME argument is a slot name. An ERROR is SIGNALled if this argument
+ is not a symbol which can be used as a variable name. An ERROR is SIGNALled
+ if this argument is not supplied."
+ Test case:
+ (make-instance (find-class 'sb-pcl:standard-direct-slot-definition))
+ Expected: ERROR
+ Got: #<SB-MOP:STANDARD-DIRECT-SLOT-DEFINITION NIL>
+
+363: missing error when a slot-definition is created with a wrong documentation object
+ (reported by Bruno Haible)
+ The MOP says about slot-definition initialization:
+ "The :DOCUMENTATION argument is a STRING or NIL. An ERROR is SIGNALled
+ if it is not. This argument default to NIL during initialization."
+ Test case:
+ (make-instance (find-class 'sb-pcl:standard-direct-slot-definition)
+ :name 'foo
+ :documentation 'not-a-string)
+ Expected: ERROR
+ Got: #<SB-MOP:STANDARD-DIRECT-SLOT-DEFINITION FOO>
+
+369: unlike-an-intersection behavior of VALUES-TYPE-INTERSECTION
+ In sbcl-0.8.18.2, the identity $(x \cap y \cap y)=(x \cap y)$
+ does not hold for VALUES-TYPE-INTERSECTION, even for types which
+ can be intersected exactly, so that ASSERTs fail in this test case:
+ (in-package :cl-user)
+ (let ((types (mapcar #'sb-c::values-specifier-type
+ '((values (vector package) &optional)
+ (values (vector package) &rest t)
+ (values (vector hash-table) &rest t)
+ (values (vector hash-table) &optional)
+ (values t &optional)
+ (values t &rest t)
+ (values nil &optional)
+ (values nil &rest t)
+ (values sequence &optional)
+ (values sequence &rest t)
+ (values list &optional)
+ (values list &rest t)))))
+ (dolist (x types)
+ (dolist (y types)
+ (let ((i (sb-c::values-type-intersection x y)))
+ (assert (sb-c::type= i (sb-c::values-type-intersection i x)))
+ (assert (sb-c::type= i (sb-c::values-type-intersection i y)))))))
+
+370: reader misbehaviour on large-exponent floats
+ (read-from-string "1.0s1000000000000000000000000000000000000000")
+ causes the reader to attempt to create a very large bignum (which it
+ will then attempt to coerce to a rational). While this isn't
+ completely wrong, it is probably not ideal -- checking the floating
+ point control word state and then returning the relevant float
+ (most-positive-short-float or short-float-infinity) or signalling an
+ error immediately would seem to make more sense.
+
+372: floating-point overflow not signalled on ppc/darwin
+ The following assertions in float.pure.lisp fail on ppc/darwin
+ (Mac OS X version 10.3.7):
+ (assert (raises-error? (scale-float 1.0 most-positive-fixnum)
+ floating-point-overflow))
+ (assert (raises-error? (scale-float 1.0d0 (1+ most-positive-fixnum))
+ floating-point-overflow)))
+ as the SCALE-FLOAT just returns
+ #.SB-EXT:SINGLE/DOUBLE-FLOAT-POSITIVE-INFINITY. These tests have been
+ disabled on Darwin for now.
+
+377: Memory fault error reporting
+ On those architectures where :C-STACK-IS-CONTROL-STACK is in
+ *FEATURES*, we handle SIG_MEMORY_FAULT (SEGV or BUS) on an altstack,
+ so we cannot handle the signal directly (as in interrupt_handle_now())
+ in the case when the signal comes from some external agent (the user
+ using kill(1), or a fault in some foreign code, for instance). As
+ of sbcl-0.8.20.20, this is fixed by calling
+ arrange_return_to_lisp_function() to a new error-signalling
+ function, but as a result the error reporting is poor: we cannot
+ even tell the user at which address the fault occurred. We should
+ arrange such that arguments can be passed to the function called from
+ arrange_return_to_lisp_function(), but this looked hard to do in
+ general without suffering from memory leaks.
+
+379: TRACE :ENCAPSULATE NIL broken on ppc/darwin
+ See commented-out test-case in debug.impure.lisp.
+
+380: Accessor redefinition fails because of old accessor name
+ When redefining an accessor, SB-PCL::FIX-SLOT-ACCESSORS may try to
+ find the generic function named by the old accessor name using
+ ENSURE-GENERIC-FUNCTION and then remove the old accessor's method in
+ the GF. If the old name does not name a function, or if the old name
+ does not name a generic function, no attempt to find the GF or remove
+ any methods is made.
+
+ However, if an unrelated GF with an incompatible lambda list exists,
+ the class redefinition will fail when SB-PCL::REMOVE-READER-METHOD
+ tries to find and remove a method with an incompatible lambda list
+ from the unrelated generic function.
+
+382: externalization unexpectedly changes array simplicity
+ COMPILE-FILE and LOAD
+ (defun foo ()
+ (let ((x #.(make-array 4 :fill-pointer 0)))
+ (values (eval `(typep ',x 'simple-array))
+ (typep x 'simple-array))))
+ then (FOO) => T, NIL.
+
+ Similar problems exist with SIMPLE-ARRAY-P, ARRAY-HEADER accessors
+ and all array dimension functions.
+
+383: ASH'ing non-constant zeros
+ Compiling
+ (lambda (b)
+ (declare (type (integer -2 14) b))
+ (declare (ignorable b))
+ (ash (imagpart b) 57))
+ on PPC (and other platforms, presumably) gives an error during the
+ emission of FASH-ASH-LEFT/FIXNUM=>FIXNUM as the assembler attempts to
+ stuff a too-large constant into the immediate field of a PPC
+ instruction. Either the VOP should be fixed or the compiler should be
+ taught how to transform this case away, paying particular attention
+ to side-effects that might occur in the arguments to ASH.
+
+384: Compiler runaway on very large character types
+
+ (compile nil '(lambda (x)
+ (declare (type (member #\a 1) x))
+ (the (member 1 nil) x)))
+
+ The types apparently normalize into a very large type, and the compiler
+ gets lost in REMOVE-DUPLICATES. Perhaps the latter should use
+ a better algorithm (one based on hash tables, say) on very long lists
+ when :TEST has its default value?
+
+ A simpler example:
+
+ (compile nil '(lambda (x) (the (not (eql #\a)) x)))
+
+ (partially fixed in 0.9.3.1, but a better representation for these
+ types is needed.)
+
+385:
+ (format nil "~4,1F" 0.001) => "0.00" (should be " 0.0");
+ (format nil "~4,1@F" 0.001) => "+.00" (should be "+0.0").
+
+386: SunOS/x86 stack exhaustion handling broken
+ According to <http://alfa.s145.xrea.com/sbcl/solaris-x86.html>, the
+ stack exhaustion checking (implemented with a write-protected guard
+ page) does not work on SunOS/x86.
+
+388:
+ (found by Dmitry Bogomolov)
+
+ (defclass foo () ((x :type (unsigned-byte 8))))
+ (defclass bar () ((x :type symbol)))
+ (defclass baz (foo bar) ())
+
+ causes error
+
+ SB-PCL::SPECIALIZER-APPLICABLE-USING-TYPE-P cannot handle the second argument
+ (UNSIGNED-BYTE 8).
+
+ [ Can't trigger this any more, as of 2006-08-07 ]
+
+389:
+ (reported several times on sbcl-devel, by Rick Taube, Brian Rowe and
+ others)
+
+ ROUND-NUMERIC-BOUND assumes that float types always have a FORMAT
+ specifying whether they're SINGLE or DOUBLE. This is true for types
+ computed by the type system itself, but the compiler type derivation
+ short-circuits this and constructs non-canonical types. A temporary
+ fix was made to ROUND-NUMERIC-BOUND for the sbcl-0.9.6 release, but
+ the right fix is to remove the abstraction violation in the
+ compiler's type deriver.
+
+393: Wrong error from methodless generic function
+ (DEFGENERIC FOO (X))
+ (FOO 1 2)
+ gives NO-APPLICABLE-METHOD rather than an argument count error.
+
+395: Unicode and streams
+ One of the remaining problems in SBCL's Unicode support is the lack
+ of generality in certain streams.
+ a. FILL-POINTER-STREAMs: SBCL refuses to write (e.g. using FORMAT)
+ to streams made from strings that aren't character strings with
+ fill-pointers:
+ (let ((v (make-array 5 :fill-pointer 0 :element-type 'standard-char)))
+ (format v "foo")
+ v)
+ should return a non-simple base string containing "foo" but
+ instead errors.
+
+ (reported on sbcl-help by "tichy")
+
+396: block-compilation bug
+ (let ((x 1))
+ (dotimes (y 10)
+ (let ((y y))
+ (when (funcall (eval #'(lambda (x) (eql x 2))) y)
+ (defun foo (z)
+ (incf x (incf y z))))))
+ (defun bar (z)
+ (foo z)
+ (values x)))
+ (bar 1) => 11, should be 4.
+
+397: SLEEP accuracy
+ The more interrupts arrive the less accurate SLEEP's timing gets.
+ (time (sb-thread:terminate-thread
+ (prog1 (sb-thread:make-thread (lambda ()
+ (loop
+ (princ #\!)
+ (force-output)
+ (sb-ext:gc))))
+ (sleep 1))))
+
+398: GC-unsafe SB-ALIEN string deporting
+ Translating a Lisp string to an alien string by taking a SAP to it
+ as done by the :DEPORT-GEN methods for C-STRING and UTF8-STRING
+ is not safe, since the Lisp string can move. For example the
+ following code will fail quickly on both cheneygc and pre-0.9.8.19
+ GENCGC:
+
+ (setf (bytes-consed-between-gcs) 4096)
+ (define-alien-routine "strcmp" int (s1 c-string) (s2 c-string))
+
+ (loop
+ (let ((string "hello, world"))
+ (assert (zerop (strcmp string string)))))
+
+ (This will appear to work on post-0.9.8.19 GENCGC, since
+ the GC no longer zeroes memory immediately after releasing
+ it after a minor GC. Either enabling the READ_PROTECT_FREE_PAGES
+ #define in gencgc.c or modifying the example so that a major
+ GC will occasionally be triggered would unmask the bug.)
+
+ On cheneygc the only solution would seem to be allocating some alien
+ memory, copying the data over, and arranging that it's freed once we
+ return. For GENCGC we could instead try to arrange that the string
+ from which the SAP is taken is always pinned.
+
+ For some more details see comments for (define-alien-type-method
+ (c-string :deport-gen) ...) in host-c-call.lisp.
+
+402: "DECLAIM DECLARATION does not inform the PCL code-walker"
+ reported by Vincent Arkesteijn:
+
+ (declaim (declaration foo))
+ (defgeneric bar (x))
+ (defmethod bar (x)
+ (declare (foo x))
+ x)
+
+ ==> WARNING: The declaration FOO is not understood by
+ SB-PCL::SPLIT-DECLARATIONS.
+ Please put FOO on one of the lists SB-PCL::*NON-VAR-DECLARATIONS*,
+ SB-PCL::*VAR-DECLARATIONS-WITH-ARG*, or
+ SB-PCL::*VAR-DECLARATIONS-WITHOUT-ARG*.
+ (Assuming it is a variable declaration without argument).
+
+403: FORMAT/PPRINT-LOGICAL-BLOCK of CONDITIONs ignoring *PRINT-CIRCLE*
+ In sbcl-0.9.13.34,
+ (defparameter *c*
+ (make-condition 'simple-error
+ :format-control "ow... ~S"
+ :format-arguments '(#1=(#1#))))
+ (setf *print-circle* t *print-level* 4)
+ (format nil "~@<~A~:@>" *c*)
+ gives
+ "ow... (((#)))"
+ where I (WHN) believe the correct result is "ow... #1=(#1#)",
+ like the result from (PRINC-TO-STRING *C*). The question of
+ what the correct result is is complicated by the hairy text in
+ the Hyperspec "22.3.5.2 Tilde Less-Than-Sign: Logical Block",
+ Other than the difference in its argument, ~@<...~:> is
+ exactly the same as ~<...~:> except that circularity detection
+ is not applied if ~@<...~:> is encountered at top level in a
+ format string.
+ But because the odd behavior happens even without the at-sign,
+ (format nil "~<~A~:@>" (list *c*)) ; => "ow... (((#)))"
+ and because something seemingly similar can happen even in
+ PPRINT-LOGICAL-BLOCK invoked directly without FORMAT,
+ (pprint-logical-block (*standard-output* '(some nonempty list))
+ (format *standard-output* "~A" '#1=(#1#)))
+ (which prints "(((#)))" to *STANDARD-OUTPUT*), I don't think
+ that the 22.3.5.2 trickiness is fundamental to the problem.
+
+ My guess is that the problem is related to the logic around the MODE
+ argument to CHECK-FOR-CIRCULARITY, but I haven't reverse-engineered
+ enough of the intended meaning of the different MODE values to be
+ confident of this.
+
+404: nonstandard DWIMness in LOOP with unportably-ordered clauses
+ In sbcl-0.9.13, the code
+ (loop with stack = (make-array 2 :fill-pointer 2 :initial-element t)
+ for length = (length stack)
+ while (plusp length)
+ for element = (vector-pop stack)
+ collect element)
+ compiles without error or warning and returns (T T). Unfortunately,
+ it is inconsistent with the ANSI definition of the LOOP macro,
+ because it mixes up VARIABLE-CLAUSEs with MAIN-CLAUSEs. Furthermore,
+ SBCL's interpretation of the intended meaning is only one possible,
+ unportable interpretation of the noncompliant code; in CLISP 2.33.2,
+ the code compiles with a warning
+ LOOP: FOR clauses should occur before the loop's main body
+ and then fails at runtime with
+ VECTOR-POP: #() has length zero
+ perhaps because CLISP has shuffled the clauses into an
+ ANSI-compliant order before proceeding.
+
+405: a TYPE-ERROR in MERGE-LETS exercised at DEBUG 3
+ In sbcl-0.9.16.21 on linux/86, compiling
+ (declaim (optimize (debug 3)))
+ (defstruct foo bar)
+ (let ()
+ (flet ((i (x) (frob x (foo-bar foo))))
+ (i :five)))
+ causes a TYPE-ERROR
+ The value NIL is not of type SB-C::PHYSENV.
+ in MERGE-LETS.
+
+406: functional has external references -- failed aver
+ Given the following food in a single file
+ (eval-when (:compile-toplevel :load-toplevel :execute)
+ (defstruct foo3))
+ (defstruct bar
+ (foo #.(make-foo3)))
+ as of 0.9.18.11 the file compiler breaks on it:
+ failed AVER: "(NOT (FUNCTIONAL-HAS-EXTERNAL-REFERENCES-P CLAMBDA))"
+ Defining the missing MAKE-LOAD-FORM method makes the error go away.
+
+407: misoptimization of loop, COERCE 'FLOAT, and HANDLER-CASE for bignums
+ (reported by Ariel Badichi on sbcl-devel 2007-01-09)
+ 407a: In sbcl-1.0.1 on Linux x86,
+ (defun foo ()
+ (loop for n from (expt 2 1024) do
+ (handler-case
+ (coerce n 'single-float)
+ (simple-type-error ()
+ (format t "Got here.~%")
+ (return-from foo)))))
+ (foo)
+ causes an infinite loop, where handling the error would be expected.
+ 407b: In sbcl-1.0.1 on Linux x86,
+ (defun bar ()
+ (loop for n from (expt 2 1024) do
+ (handler-case
+ (format t "~E~%" (coerce n 'single-float))
+ (simple-type-error ()
+ (format t "Got here.~%")
+ (return-from bar)))))
+ fails to compile, with
+ Too large to be represented as a SINGLE-FLOAT: ...
+ from
+ 0: ((LABELS SB-BIGNUM::CHECK-EXPONENT) ...)
+ 1: ((LABELS SB-BIGNUM::FLOAT-FROM-BITS) ...)
+ 2: (SB-KERNEL:%SINGLE-FLOAT ...)
+ 3: (SB-C::BOUND-FUNC ...)
+ 4: (SB-C::%SINGLE-FLOAT-DERIVE-TYPE-AUX ...)
+
+408: SUBTYPEP confusion re. OR of SATISFIES of not-yet-defined predicate
+ As reported by Levente M\'{e}sz\'{a}ros sbcl-devel 2006-02-20,
+ (aver (equal (multiple-value-list
+ (subtypep '(or (satisfies x) string)
+ '(or (satisfies x) integer)))
+ '(nil nil)))
+ fails. Also, beneath that failure lurks another failure,
+ (aver (equal (multiple-value-list
+ (subtypep 'string
+ '(or (satisfies x) integer)))
+ '(nil nil)))
+ Having looked at this for an hour or so in sbcl-1.0.2, and
+ specifically having looked at the output from
+ laptop$ sbcl
+ * (let ((x 'string)
+ (y '(or (satisfies x) integer)))
+ (trace sb-kernel::union-complex-subtypep-arg2
+ sb-kernel::invoke-complex-subtypep-arg1-method
+ sb-kernel::type-union
+ sb-kernel::type-intersection
+ sb-kernel::type=)
+ (subtypep x y))
+ my (WHN) impression is that the problem is that the semantics of TYPE=
+ are wrong for what the UNION-COMPLEX-SUBTYPEP-ARG2 code is trying
+ to use it for. The comments on the definition of TYPE= probably
+ date back to CMU CL and seem to define it as a confusing thing:
+ its primary value is something like "certainly equal," and its
+ secondary value is something like "certain about that certainty."
+ I'm left uncertain how to fix UNION-COMPLEX-SUBTYPEP-ARG2 without
+ reducing its generality by removing the TYPE= cleverness. Possibly
+ the tempting TYPE/= relative defined next to it might be a
+ suitable replacement for the purpose. Probably, though, it would
+ be best to start by reverse engineering exactly what TYPE= and
+ TYPE/= do, and writing an explanation which is so clear that one
+ can see immediately what it's supposed to mean in odd cases like
+ (TYPE= '(SATISFIES X) 'INTEGER) when X isn't defined yet.
+
+409: MORE TYPE SYSTEM PROBLEMS
+ Found while investigating an optimization failure for extended
+ sequences. The extended sequence type implementation was altered to
+ work around the problem, but the fundamental problem remains, to wit:
+ (sb-kernel:type= (sb-kernel:specifier-type '(or float ratio))
+ (sb-kernel:specifier-type 'single-float))
+ returns NIL, NIL on sbcl-1.0.3.
+ (probably related to bug #408)
+
+410: read circularities and type declarations
+ Consider the definition
+ (defstruct foo (a 0 :type (not symbol)))
+ followed by
+ (setf *print-circle* t) ; just in case
+ (read-from-string "#1=#s(foo :a #1#)")
+ This gives a type error (#:G1 is not a (NOT SYMBOL)) because of the
+ implementation of read circularity, using a symbol as a marker for
+ the previously-referenced object.
+
+411: NAN issues on x86-64
+ Test :NAN-COMPARISONS in float.pure.lisp fails on x86-64, and has been
+ disabled on those platforms. Since x86 does not exhibit any problems
+ the problem is probably with the new FP implementation.
+
+413: type-errors in ROOM
+
+ (defvar *a* (make-array (expt 2 27)))
+ (room)
+
+ Causes a type-error on 32bit SBCL, as various byte-counts in ROOM
+ implementation overrun fixnums.
+
+ This was fixed in 1.0.4.89, but the patch was reverted as it caused
+ ROOM to cons sufficiently to make running it in a loop deadly on
+ GENCGC: newly allocated objects survived to generation 1, where next
+ call to ROOM would see them, and allocate even more...
+
+ Reported by Faré Rideau on sbcl-devel.
+
+414: strange DISASSEMBLE warning
+
+ Compiling and disassembling
+
+ (defun disassemble-source-form-bug (x y z)
+ (declare (optimize debug))
+ (list x y z))
+
+ Gives
+
+ WARNING: bogus form-number in form! The source file has probably
+ been changed too much to cope with.
+
+415: Issues creating large arrays on x86-64/Linux and x86/Darwin
+
+ (make-array (1- array-dimension-limit))
+
+ causes a GC invariant violation on x86-64/Linux, and
+ an unhandled SIGILL on x86/Darwin.
+
+416: backtrace confusion
+
+ (defun foo (x)
+ (let ((v "foo"))
+ (flet ((bar (z)
+ (oops v z)
+ (oops z v)))
+ (bar x)
+ (bar v))))
+ (foo 13)
+
+ gives the correct error, but the backtrace shows
+ 1: (SB-KERNEL:FDEFINITION-OBJECT 13 NIL)
+ as the second frame.
+
+
+
+