1. 19 Aug, 2021 1 commit
  2. 18 Jun, 2021 1 commit
  3. 07 Oct, 2020 1 commit
  4. 16 Sep, 2020 1 commit
    • Martin Bidlingmaier's avatar
      [regexp] Support capture groups in experimental engine · 98b8ca89
      Martin Bidlingmaier authored
      This commit adds support for capture groups (as in e.g. /x(123|abc)y/)
      in the experimental regexp engine.  Now every InterpreterThread owns a
      register array containing (sub)match boundaries. There is a new
      instruction to record the current input index in some register.
      
      Submatches in quantifier bodies should be reported only if they occur
      during the last repetition.  Thus we reset those registers before
      attempting to match the body of a quantifier.  This is implemented with
      another new instruction.
      
      Because of concerns for the growing sizeof the NfaInterpreter object
      (which is allocated on the stack), this commit replaces the
      `SmallVector` members of the NfaInterpreter with zone-allocated arrays.
      Register arrays, which for a fixed regexp are all the same size, are
      allocated with a RecyclingZoneAllocator for cheap memory reclamation via
      a linked list of equally-sized free blocks.
      
      Possible optimizations for management of register array memory:
      1. If there are few register per thread, then it is likely faster to
         store them inline in the InterpreterThread struct.
      2. re2 implements copy-on-write:  InterpreterThreads can share the same
         register array. If a thread attempts to write to shared register
         array, the register array is cloned first.
      3. The register at index 1 contains the end of the match; this is only
         written to right before an ACCEPT statement.  We could make ACCEPT
         equivalent to what's currently CAPTURE 1 followed by ACCEPT.  We
         could then save the memory for register 1 for threads that haven't
         finished yet.  This is particularly interesting if now optimization 1
         kicks in.
      
      Cq-Include-Trybots: luci.v8.try:v8_linux64_fyi_rel_ng
      Bug: v8:10765
      Change-Id: I2c0503206ce331e13ac9912945bb66736d740197
      Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2390770
      Commit-Queue: Martin Bidlingmaier <mbid@google.com>
      Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
      Cr-Commit-Position: refs/heads/master@{#69929}
      98b8ca89
  5. 01 Sep, 2020 1 commit