Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-6561457

merge-o in fix to 6516101 bogusly sets the null_seen bit.

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P2
    • Resolution: Fixed
    • Affects Version/s: 7
    • Fix Version/s: hs10
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
    • Introduced In Build:
      b08
    • Introduced In Version:
      7
    • Resolved In Build:
      b14
    • CPU:
      generic
    • OS:
      generic

      Backports

        Description

        The following line was introduced twice in each of two files:
            set_mdp_flag_at(mdp, BitData::null_seen_byte_constant());

        The files are:
            src/cpu/amd64/vm/interp_masm_amd64.cpp
            src/cpu/i486/vm/interp_masm_i486.cpp

        The lines were apparently introduced by re-application of a patch.
        Their contexts are extremely similar, but one context is the correct
        location and the other is incorrect. The bug is that the null_seen
        bit is set in the MDO on code paths generated by both
        profile_null_seen and profile_typecheck in InterpreterMacroAssembler.
        Only the former should set that bit. The result is that the
        server compiler always performs a careful explicit null check
        on the casted oop, instead of (what should be the usual case)
        an implicit null check.

        Fix is to remove the duplicate lines, one from each file.

          Attachments

            Issue Links

              Activity

                People

                • Assignee:
                  jrose John Rose
                  Reporter:
                  jrose John Rose
                • Votes:
                  0 Vote for this issue
                  Watchers:
                  0 Start watching this issue

                  Dates

                  • Created:
                    Updated:
                    Resolved:
                    Imported:
                    Indexed: