Custom Query (1030 matches)

./lx86cl
(load "home:quicklisp;setup")
(ql:quickload :manardb)
(in-package :manardb)
(defun junk () (lisp-object-to-mptr nil))
> Error: Compiler bug or inconsistency:
>        x862-form to freg #<ACODE nil NIL>

The following code works fine in ccl-1.9:

(in-package :cl-user)

(defun abc ()
  (let* ((body
           '(let ((cache (load-time-value (cons (cons nil nil) nil))))
             (let ((fn #'(lambda () t)))
               (setf (car cache) (cons fn t))
               (values (funcall (caar cache))))))
         (thunk (compile nil `(lambda () ,body))))
    (disassemble thunk)
    (funcall thunk)))

(print (abc))

but fails with "Error of type CCL::INVALID-MEMORY-ACCESS: Fault during read of memory address #x0" error on (funcall (caar cache)) form in trunk and ccl-1.10.

The code was distilled from a piece of code utilizing LOAD-TIME-VALUE cache pattern as in ​http://random-state.net/log/3507100003.html (I used it in a compiler macro)

The problem can be currently worked around by commenting out (multiple-value-bind ...) form in (def-acode-rewrite acode-rewrite-cxr ...) in compiler/acode-rewrite.lisp: http://trac.clozure.com/ccl/browser/trunk/source/compiler/acode-rewrite.lisp?rev=16571#L567

Disassembly output before applying the workaround. Looks like the compiler treats (load-time-value (cons (cons nil nil) nil)) as a read-only constant value that cannot be changed:

    (recover-fn-from-rip)                   ;     [7]
    (testl (% nargs) (% nargs))             ;    [14]
    (jne L149)                              ;    [16]
    (pushq (% rbp))                         ;    [22]
    (movq (% rsp) (% rbp))                  ;    [23]
    (movq (@ '#<Anonymous Function #x302000B53A9F> (% fn)) (% arg_z)) ;    [26]
    (pushq (% arg_z))                       ;    [33]
    (movq (@ '((NIL)) (% fn)) (% arg_y))    ;    [34]
    (pushq (% arg_y))                       ;    [41]
    (movq (@ -8 (% rbp)) (% arg_y))         ;    [42]
    (movl ($ #x1302E) (% arg_z.l))          ;    [46]
    (subq ($ 13) (@ (% gs) #xD8))           ;    [51]
    (movq (@ (% gs) #xD8) (% temp0))        ;    [61]
    (cmpq (@ (% gs) #xE0) (% temp0))        ;    [70]
    (ja L76)                                ;    [79]
    (uuo-alloc)                             ;    [81]
L76
    (andb ($ #xF0) (@ (% gs) #xD8))         ;    [83]
    (movq (% arg_y) (@ 5 (% temp0)))        ;    [92]
    (movq (% arg_z) (@ -3 (% temp0)))       ;    [96]
    (movq (% temp0) (% arg_z))              ;   [100]
    (popq (% arg_y))                        ;   [103]
    (lisp-call  (@ .SPRPLACA))              ;   [109]
    (recover-fn-from-rip)                   ;   [116]
    (xorl (% nargs) (% nargs))              ;   [123]
    (movq (@ 'NIL (% fn)) (% temp0))        ;   [125]
    (lisp-call (@ 10 (% temp0)))            ;   [137]
    (recover-fn-from-rip)                   ;   [140]
    (leaveq)                                ;   [147]
    (retq)                                  ;   [148]
L149
    (uuo-error-wrong-number-of-args)

Disassembly output after applying the workaround:

    (recover-fn-from-rip)                   ;     [7]
    (testl (% nargs) (% nargs))             ;    [14]
    (jne L193)                              ;    [16]
    (pushq (% rbp))                         ;    [22]
    (movq (% rsp) (% rbp))                  ;    [23]
    (movq (@ '#<Anonymous Function #x302000B0A71F> (% fn)) (% arg_z)) ;    [26]
    (pushq (% arg_z))                       ;    [33]
    (movq (@ '((NIL)) (% fn)) (% arg_y))    ;    [34]
    (pushq (% arg_y))                       ;    [41]
    (movq (@ -8 (% rbp)) (% arg_y))         ;    [42]
    (movl ($ #x1302E) (% arg_z.l))          ;    [46]
    (subq ($ 13) (@ (% gs) #xD8))           ;    [51]
    (movq (@ (% gs) #xD8) (% temp0))        ;    [61]
    (cmpq (@ (% gs) #xE0) (% temp0))        ;    [70]
    (ja L76)                                ;    [79]
    (uuo-alloc)                             ;    [81]
L76 
    (andb ($ #xF0) (@ (% gs) #xD8))         ;    [83]
    (movq (% arg_y) (@ 5 (% temp0)))        ;    [92]
    (movq (% arg_z) (@ -3 (% temp0)))       ;    [96]
    (movq (% temp0) (% arg_z))              ;   [100]
    (popq (% arg_y))                        ;   [103]
    (lisp-call  (@ .SPRPLACA))              ;   [109]
    (recover-fn-from-rip)                   ;   [116]
    (movq (@ '((NIL)) (% fn)) (% arg_z))    ;   [123]
    (movq (@ 5 (% arg_z)) (% arg_z))        ;   [130]
    (movl (% arg_z.l) (% imm0.l))           ;   [134]
    (andl ($ 7) (% imm0.l))                 ;   [136]
    (cmpl ($ 3) (% imm0.l))                 ;   [139]
    (jne L201)                              ;   [142]
    (movq (@ 5 (% arg_z)) (% arg_z))        ;   [144]
    (pushq (% arg_z))                       ;   [148]
    (movq (@ -16 (% rbp)) (% temp0))        ;   [149]
    (xorl (% nargs) (% nargs))              ;   [153]
    (movl (% temp0.l) (% imm0.l))           ;   [155]
    (andl ($ 15) (% imm0.l))                ;   [157]
    (cmpl ($ 14) (% imm0.l))                ;   [160]
    (cmovgq (% temp0) (% temp1))            ;   [163]
    (jl L209)                               ;   [167]
    (cmoveq (@ 10 (% temp0)) (% temp1))     ;   [169]
    (lisp-call (% temp1))                   ;   [177]
    (recover-fn-from-rip)                   ;   [180]
    (addq ($ 8) (% rsp))                    ;   [187]
    (leaveq)                                ;   [191]
    (retq)                                  ;   [192]
L193
    (uuo-error-wrong-number-of-args)        ;   [200]
L201
    (uuo-error-reg-not-list (% arg_z))      ;   [208]
L209
    (uuo-error-not-callable)                ;   [216]

After doing (rebuild-ccl :full t) on an OS X 10.11 system, (require 'cocoa) will fail by crashing into the lisp kernel debugger. A slightly simpler test case is (require 'objc-support), but that doesn't fully exercise things.

As I mentioned earlier today, I believe that this is (at least in part) because Objective-C isa pointers are not necessarily pointers any more.

Starting the lisp with the environment variable OBJC_DISABLE_NONPOINTER_ISA set to YES will enable the (require 'cocoa) to succeed.

$ env OBJC_DISABLE_NONPOINTER_ISA=YES ccl

(I found this out on ​http://www.sealiesoftware.com/blog/archive/2013/09/24/objc_explain_Non-pointer_isa.html)