• Tobias Tebbi's avatar
    [builtins] add Torque fast-path for String.prototype.localeCompare · 6181ce59
    Tobias Tebbi authored
    This fast path works for ASCII-only strings and is similar to the
    existing fast-path in C++. Important differences:
    - The locale check is done at Turbofan optimization time instead of
      at runtime
    - Use tables of size 256 instead of 128 to save a bounds-check when
      handling one-byte strings.
    - It first performs an equality check that's optimized for detecting
      inequality quickly by comparing the strings from both ends. If the
      equality check succeeds, we are done. Otherwise chances are high
      that the strings differ according to collation level L1 already.
      Therefore, we first do an L1 check and perform the L3 check
      only when L1 didn't find a difference. This is based on the assumption
      that few strings are identical except for different capitalization.
    - Use the Torque version of string flattening instead of the runtime
      version.
    
    Bug: v8:12196
    Change-Id: I2d043c1138846783f6d567b736d34063ba9301e5
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3268465Reviewed-by: 's avatarJakob Kummerow <jkummerow@chromium.org>
    Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
    Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
    Cr-Commit-Position: refs/heads/main@{#77946}
    6181ce59
base.tq 71 KB