TRACE :ENCAPSULATE NIL broken on darwin

Bug #309067 reported by Nikodemus Siivola on 2008-12-17
2
Affects Status Importance Assigned to Milestone
SBCL
Medium
Unassigned

Bug Description

Commented-out test-case in debug.impure.lisp:

;;; This is not a WITH-TEST :FAILS-ON PPC DARWIN since there are
;;; suspicions that the breakpoint trace might corrupt the whole image
;;; on that platform.
#-(and (or ppc x86 x86-64) darwin)
(with-test (:name (trace :encapsulate nil)
            :fails-on '(or :ppc :sparc :mips))
  (let ((out (with-output-to-string (*trace-output*)
               (trace trace-this :encapsulate nil)
               (assert (eq 'ok (trace-this)))
               (untrace))))
    (assert (search "TRACE-THIS" out))
    (assert (search "returned OK" out))))

description: updated
Changed in sbcl:
importance: Undecided → Medium
status: New → Confirmed
Nikodemus Siivola (nikodemus) wrote :

As long as the suspicion remains, attaching big runtime warning to doing a breakpoint trace on Darwin seems like a good idea. (Once that is done the importance can be downgraded, imo.)

Changed in sbcl:
importance: Medium → High
Nikodemus Siivola (nikodemus) wrote :

Breakpoints are currently broken on x86[-64]/darwin as we use an illegal instruction instead of INT3 to trap, but the runtime installs INT3 as a trap.

This arrangement is due to historical flakiness: it used to be possible to lose a SIGTRAP on darwin. I'm not sure if this is still the case. If not, we can just go back to INT3, if not we should teach the runtime to use illegal instruction traps instead.

As of 1.0.36.9, the runtime has been taught to use illegal instruction traps when appropriate. I don't have a mac, so I can't proceed further.

Nikodemus Siivola (nikodemus) wrote :

Not quite there on Darwin yet, unfortunately.

http://thread.gmane.org/gmane.lisp.steel-bank.cvs/13959/focus=14571

Knocking this down to Medium importance because TRACE :ENCAPSULATE NIL is broken on all non-x86oid targets, and because there has been no activity on this for nearly three months, and no activity for about eight months before that.

Changed in sbcl:
importance: High → Medium
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