Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-4179816

illegal optimization of field access which result is unused

    Details

    • Subcomponent:
      jit
    • CPU:
      x86
    • OS:
      solaris_2.5.1

      Description



      Name: akC45999 Date: 10/08/98



      Some tests try to access unexisting or unaccessible field and expect an
      exception. But the JIT removes field access instructions because the
      result is never used. So no exception occured. It is illegal optimization,
      because it may affect the observable behavior of the program.
      For example, after such optimization following tests does not
      throw exceptions described in JVMS section 5.2 "Field and Method
      Resolution" as expected.

      The bug causes failures of the following tests of JCK12a under JDK12fcsM(x86)

      vm/constantpool/userDefined/userDefined002/userDefined00201/userDefined00201
      vm/instr/getfield/getfield006/getfield00605m1/getfield00605m1
      vm/instr/getfield/getfield011/getfield01101m1/getfield01101m1
      vm/instr/getfield/getfield011/getfield01103m1/getfield01103m1
      vm/instr/getfield/getfield013/getfield01301m1/getfield01301m1
      vm/instr/getfield/getfield013/getfield01302m1/getfield01302m1
      vm/instr/getstatic/getstatic008/getstatic00801m1/getstatic00801m1
      vm/instr/getstatic/getstatic008/getstatic00802m1/getstatic00802m1
      vm/instr/getstatic/getstatic008/getstatic00803m1/getstatic00803m1
      vm/instr/getstatic/getstatic010/getstatic01001m1/getstatic01001m1
      vm/instr/getstatic/getstatic011/getstatic01101m1/getstatic01101m1

      Bug may be illustrated by simple test:

      class test {
      // static Field aaa:"I";

        public static Method main:"([Ljava/lang/String;)V"
      stack 2 locals 1
      {
      getstatic aaa:I;
      return;
      }
      }

      -----------------------------------------
      ======================================================================

        Attachments

          Issue Links

            Activity

              People

              • Assignee:
                never Tom Rodriguez
                Reporter:
                rfqsunw Rfq Rfq (Inactive)
              • Votes:
                0 Vote for this issue
                Watchers:
                0 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved:
                  Imported:
                  Indexed: