Changeset 12904

Timestamp:

Oct 2, 2009, 8:48:00 PM (15 years ago)

Author:

R. Matthew Emerson

Message:

In XCMAIN, return SKIP bytes rather than unconditionally 0. Offer
an "ignore this write" restart.

New function X86-FAULTING-INSTRUCTION.

File:

• branches/watchpoints/level-1/x86-trap-support.lisp (modified) (3 diffs)

branches/watchpoints/level-1/x86-trap-support.lisp

@@ -387 +387 @@
 ;;; may not be meaningful.
 (defcallback xcmain (:address xp :address xcf :int signal :long code :long addr :long other :int)
-  (let* ((frame-ptr (macptr->fixnum xcf)))
+  (let* ((frame-ptr (macptr->fixnum xcf))
+         (skip 0))
     (cond ((zerop signal)               ;thread interrupt
            (cmain))
@@ -436 +437 @@
                          (%get-object a 0))))
                 (let ((object (%int-to-object other)))
-                  (restart-case (%error (make-condition
-                                         'write-to-watched-object
-                                         :address addr
-                                         :object object)
-                                        nil frame-ptr)
-                    (unwatch ()
-                      :report (lambda (s)
-                                (format s "Unwatch ~s and perform the write." object))
-                      (unwatch object))))))))
+                  (multiple-value-bind (insn insn-length)
+                      (x86-faulting-instruction xp)
+                    (restart-case (%error (make-condition
+                                           'write-to-watched-object
+                                           :instruction insn
+                                           :address addr
+                                           :object object)
+                                          nil frame-ptr)
+                      (ignore ()
+                        :report "Ignore this write."
+                        (setq skip insn-length))
+                      (unwatch ()
+                        :report (lambda (s)
+                                  (format s "Unwatch ~s and perform the write." object))
+                        (unwatch object)))))))))
           ((= signal #+win32-target 10 #-win32-target #$SIGBUS)
            (if (= code -1)
@@ -454 +461 @@
                                      :write-p (not (zerop code)))
                      ()
-                     frame-ptr)))))
-  0)
+                     frame-ptr))))
+    skip))
+
+(defun x86-faulting-instruction (xp)
+  (let* ((code-bytes (make-array 15 :element-type '(unsigned-byte 8)))
+         (pc (indexed-gpr-macptr xp rip-register-offset)))
+    (dotimes (i (length code-bytes))
+      (setf (aref code-bytes i) (%get-unsigned-byte pc i)))
+    (let* ((ds (make-x86-disassembly-state
+                :mode-64 #+x8664-target t #+x8632-target nil
+                :code-vector code-bytes
+                :code-pointer 0))
+           (insn (x86-disassemble-instruction ds nil))
+           (len (- (x86-ds-code-pointer ds) (x86-ds-insn-start ds))))
+      (values insn len))))