[Sbcl-devel] x86 fixup error when dynamic heap located at > 0x80000000

[James Y K. <fo...@fu...>]

I'm getting the following error:

   The value -2164842066 is not of type (SIGNED-BYTE 32).

0] backtrace

0: ((LAMBDA (SB-IMPL::E)) #<TYPE-ERROR {810A5021}>)
1: ((LAMBDA (SB-IMPL::E)) #<TYPE-ERROR {810A5021}>)
2: (SIGNAL #<TYPE-ERROR {810A5021}>)
3: (ERROR TYPE-ERROR)
4: (SB-KERNEL::OBJECT-NOT-TYPE-ERROR-HANDLER
     #<unavailable argument>
     #.(SB-SYS:INT-SAP #X55AF65BC)
     #<ALIEN-VALUE :SAP #X55AF626C :TYPE (*
                                          (STRUCT SB-VM::OS-CONTEXT-T- 
STRUCT))>
     (142 14))
5: (SB-KERNEL:INTERNAL-ERROR
     #.(SB-SYS:INT-SAP #X55AF626C)
     #<unavailable argument>)
6: ("foreign function: call_into_lisp")
7: ("foreign function: funcall2")
8: ("foreign function: interrupt_internal_error")
9: ("foreign function: sigtrap_handler")
10: (SB-VM:FIXUP-CODE-OBJECT #<code object {8109DFAF}> 1421  
67383 :RELATIVE)
11: (SB-C::DO-CORE-FIXUPS
      #<code object {8109DFAF}>
      (#S(SB-C::FIXUP-NOTE
          :KIND :ABSOLUTE
          :FIXUP #S(SB-C:FIXUP :NAME NIL :FLAVOR :CODE-OBJECT :OFFSET  
65)
          :POSITION 1427)
       #S(SB-C::FIXUP-NOTE
          :KIND :RELATIVE
          :FIXUP #S(SB-C:FIXUP
                    :NAME SB-VM::ALLOCATE-CONS-TO-EAX
                    :FLAVOR :ASSEMBLY-ROUTINE
                    :OFFSET NIL)
          :POSITION 1421)
........

It looks to me like it's due to the following piece of code, on line  
128 of x86-vm.c. If loc-sap is at an address > 0x80000000, (which it  
seems it will be in the above traceback), then rel-val will be out of  
the range of signed-byte-32, and thus cause this error. Probably this  
code should be doing modular signed-byte 32 arithmetic rather than  
restricting the range? My sbcl has a dynamic heap that starts below  
0x80000000, but ends above it, so I didn't notice this until  
recently, since the code objects just so happened to always be below  
the boundary.

>          (:relative
>           ;; Fixup is the actual address wanted.
>           ;;
>           ;; Record relative fixups that point outside the code
>           ;; object.
>           (when (or (< fixup obj-start-addr) (> fixup code-end-addr))
>             (add-fixup code offset))
>           ;; Replace word with value to add to that loc to get there.
>           (let* ((loc-sap (+ (sap-int sap) offset))
>                  (rel-val (- fixup loc-sap n-word-bytes)))
>             (declare (type (unsigned-byte 32) loc-sap)
>                      (type (signed-byte 32) rel-val))
>             (setf (signed-sap-ref-32 sap offset) rel-val)))

James