• Nikolaos Papaspyrou's avatar
    heap: Fix and clean up object start bitmap · 4651df6b
    Nikolaos Papaspyrou authored
    This CL introduces the following changes to the experimental
    implementation of the object start bitmap, that is evaluated as
    a mechanism for resolving inner pointers (behind the flag
    v8_enable_conservative_stack_scanning):
    
    - Manually iterate through page objects, instead of using the
      PagedSpaceObjectIterator, for performance (avoid calling
      MakeHeapIterable all the time) and to simplify the handling
      of filler objects.
    - Clear bits when reusing evacuated pages of the new space.
    - Use the cage base to iterate correctly through code objects.
    - Introduce a method for verifying the validity of the object
      start bitmap.
    - Minor fixes, additional checks and cleanup.
    
    Bug: v8:12851
    Change-Id: I245937ffe6f4b53c4c2dcf5126e8836aec4dc79e
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3675099Reviewed-by: 's avatarOmer Katz <omerkatz@chromium.org>
    Reviewed-by: 's avatarDominik Inführ <dinfuehr@chromium.org>
    Commit-Queue: Nikolaos Papaspyrou <nikolaos@chromium.org>
    Cr-Commit-Position: refs/heads/main@{#80869}
    4651df6b
object-start-bitmap.h 3.78 KB