Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-8218675

Reduce verification overhead in ClassFileParser

    XMLWordPrintable

    Details

    • Subcomponent:
    • Resolved In Build:
      b08

      Description

      Code to verify method and field signatures in ClassFileParser has a number of inefficiencies:

      - Symbol names are routinely copied into stack or heap allocated buffers, sometimes unconditionally the latter
      - In verify_unqualified_name we unnecessarily test to detect non-ASCII characters: each byte in multi-byte characters will be over > 127, so it's faster to keep the loop simple, and a switch improves it further (this code is exercised by some internal calls independently of whether -Xverify mode)
      - skip_over_field_name calls both Character::isJavaIdentifierStart and Character::isJavaIdentifierPart for each unicode character

      The superfluous copying is probably a remnants from an implementation when ClassFileParser called out to the separate verifier and had to be more conservative.

      Fixing these issues add up to a 15% reduction of the bytecode verification overhead on a simple test running a Hello World with -Xshare:off -Xverify:all

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              redestad Claes Redestad
              Reporter:
              redestad Claes Redestad
              Votes:
              0 Vote for this issue
              Watchers:
              2 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved: