(/show0 "back from INFINITE-ERROR-PROTECTOR")
(let ((*current-error-depth* (1+ *current-error-depth*)))
(/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
- #+sb-show (sb-debug:backtrace)
+ ;; arbitrary truncation
+ #!+sb-show (sb!debug:backtrace 8)
,@forms)))
;;; a helper function for INFINITE-ERROR-PROTECT
;;; Zero the unused portion of the control stack so that old objects
;;; are not kept alive because of uninitialized stack variables.
-;;;
-;;; FIXME: Why do we need to do this instead of just letting GC read
-;;; the stack pointer and avoid messing with the unused portion of
-;;; the control stack? (Is this a multithreading thing where there's
-;;; one control stack and stack pointer per thread, and it might not
-;;; be easy to tell what a thread's stack pointer value is when
-;;; looking in from another thread?)
+
+;;; "To summarize the problem, since not all allocated stack frame
+;;; slots are guaranteed to be written by the time you call an another
+;;; function or GC, there may be garbage pointers retained in your
+;;; dead stack locations. The stack scrubbing only affects the part
+;;; of the stack from the SP to the end of the allocated stack."
+;;; - ram, on cmucl-imp, Tue, 25 Sep 2001
+
+;;; So, as an (admittedly lame) workaround, from time to time we call
+;;; scrub-control-stack to zero out all the unused portion. This is
+;;; supposed to happen when the stack is mostly empty, so that we have
+;;; a chance of clearing more of it: callers are currently (2002.07.18)
+;;; REPL and SUB-GC
+
(defun scrub-control-stack ()
(declare (optimize (speed 3) (safety 0))
(values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
#!-stack-grows-downward-not-upward
- (labels
- ((scrub (ptr offset count)
- (declare (type system-area-pointer ptr)
- (type (unsigned-byte 16) offset)
- (type (unsigned-byte 20) count)
- (values (unsigned-byte 20)))
- (cond ((= offset bytes-per-scrub-unit)
- (look (sap+ ptr bytes-per-scrub-unit) 0 count))
- (t
- (setf (sap-ref-32 ptr offset) 0)
- (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
- (look (ptr offset count)
- (declare (type system-area-pointer ptr)
- (type (unsigned-byte 16) offset)
- (type (unsigned-byte 20) count)
- (values (unsigned-byte 20)))
- (cond ((= offset bytes-per-scrub-unit)
- count)
- ((zerop (sap-ref-32 ptr offset))
- (look ptr (+ offset sb!vm:n-word-bytes) count))
- (t
- (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
- (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
- (initial-offset (logand csp (1- bytes-per-scrub-unit))))
+ (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
+ (initial-offset (logand csp (1- bytes-per-scrub-unit)))
+ (end-of-stack
+ (- sb!vm:control-stack-end sb!c:*backend-page-size*)))
+ (labels
+ ((scrub (ptr offset count)
+ (declare (type system-area-pointer ptr)
+ (type (unsigned-byte 16) offset)
+ (type (unsigned-byte 20) count)
+ (values (unsigned-byte 20)))
+ (cond ((>= (sap-int ptr) end-of-stack) 0)
+ ((= offset bytes-per-scrub-unit)
+ (look (sap+ ptr bytes-per-scrub-unit) 0 count))
+ (t
+ (setf (sap-ref-32 ptr offset) 0)
+ (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
+ (look (ptr offset count)
+ (declare (type system-area-pointer ptr)
+ (type (unsigned-byte 16) offset)
+ (type (unsigned-byte 20) count)
+ (values (unsigned-byte 20)))
+ (cond ((>= (sap-int ptr) end-of-stack) 0)
+ ((= offset bytes-per-scrub-unit)
+ count)
+ ((zerop (sap-ref-32 ptr offset))
+ (look ptr (+ offset sb!vm:n-word-bytes) count))
+ (t
+ (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
(declare (type (unsigned-byte 32) csp))
(scrub (int-sap (- csp initial-offset))
(* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
0)))
#!+stack-grows-downward-not-upward
- (labels
- ((scrub (ptr offset count)
- (declare (type system-area-pointer ptr)
- (type (unsigned-byte 16) offset)
- (type (unsigned-byte 20) count)
- (values (unsigned-byte 20)))
- (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
- (cond ((= offset bytes-per-scrub-unit)
- (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
- 0 count))
- (t ;; need to fix bug in %SET-STACK-REF
- (setf (sap-ref-32 loc 0) 0)
- (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
- (look (ptr offset count)
- (declare (type system-area-pointer ptr)
- (type (unsigned-byte 16) offset)
- (type (unsigned-byte 20) count)
- (values (unsigned-byte 20)))
- (let ((loc (int-sap (- (sap-int ptr) offset))))
- (cond ((= offset bytes-per-scrub-unit)
- count)
- ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
- (look ptr (+ offset sb!vm:n-word-bytes) count))
- (t
- (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
- (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
- (initial-offset (logand csp (1- bytes-per-scrub-unit))))
+ (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
+ (end-of-stack (+ sb!vm:control-stack-start sb!c:*backend-page-size*))
+ (initial-offset (logand csp (1- bytes-per-scrub-unit))))
+ (labels
+ ((scrub (ptr offset count)
+ (declare (type system-area-pointer ptr)
+ (type (unsigned-byte 16) offset)
+ (type (unsigned-byte 20) count)
+ (values (unsigned-byte 20)))
+ (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
+ (cond ((< (sap-int loc) end-of-stack) 0)
+ ((= offset bytes-per-scrub-unit)
+ (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
+ 0 count))
+ (t ;; need to fix bug in %SET-STACK-REF
+ (setf (sap-ref-32 loc 0) 0)
+ (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
+ (look (ptr offset count)
+ (declare (type system-area-pointer ptr)
+ (type (unsigned-byte 16) offset)
+ (type (unsigned-byte 20) count)
+ (values (unsigned-byte 20)))
+ (let ((loc (int-sap (- (sap-int ptr) offset))))
+ (cond ((< (sap-int loc) end-of-stack) 0)
+ ((= offset bytes-per-scrub-unit)
+ count)
+ ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
+ (look ptr (+ offset sb!vm:n-word-bytes) count))
+ (t
+ (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
(declare (type (unsigned-byte 32) csp))
(scrub (int-sap (+ csp initial-offset))
(* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
"Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
+++, ++, +, ///, //, /, and -."
(setf - form)
- (let ((results (multiple-value-list (eval form))))
+ (let ((results
+ (multiple-value-list
+ (eval-in-lexenv form
+ (make-null-interactive-lexenv)))))
(setf /// //
// /
/ results
;; get you out to here.
(with-simple-restart
(abort
- "Reduce debugger level (leaving debugger, returning to toplevel).")
+ "~@<Reduce debugger level (leaving debugger, returning to toplevel).~@:>")
(catch 'toplevel-catcher
#!-sunos (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
+ ;; in the event of a control-stack-exhausted-error, we should
+ ;; have unwound enough stack by the time we get here that this
+ ;; is now possible
+ (sb!kernel::protect-control-stack-guard-page 1)
(repl noprint)
(critically-unreachable "after REPL")))))))
(/show0 "entering REPL")
(let ((eof-marker (cons :eof nil)))
(loop
- ;; FIXME: It seems bad to have GC behavior depend on scrubbing the
- ;; control stack before each interactive command. Isn't there some
- ;; way we can convince the GC to just ignore dead areas of the
- ;; control stack, so that we don't need to rely on this half-measure?
+ ;; see comment preceding definition of SCRUB-CONTROL-STACK
(scrub-control-stack)
(unless noprint
(fresh-line)
projects / sbcl.git / blobdiff