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  1. 14 Apr, 2021 19 commits
  3. 13 Apr, 2021 19 commits
  5. 12 Apr, 2021 2 commits
    • Shu-yu Guo's avatar
      [ptr-cage] Deprecate Symbol::Description() in favor of Symbol::Description(isolate) · 153f2cea
      Shu-yu Guo authored 
      With a shared cage, there's no easy way to recover an Isolate from a
heap pointer. Symbol::Description relies on RO symbols' description slot
being uncompressed so a Handle could point to it. This isn't possible
with a shared cage without going through TLS to get an Isolate for
Handle construction, so deprecate the method in favor of one that takes
an Isolate directly.

Bug: v8:11460
Change-Id: I69b2b7d77f4c00d0f58954cd80e22cba5ff222e3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2802860
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: 's avatarRoss McIlroy <rmcilroy@chromium.org>
Reviewed-by: 's avatarDan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73924}
      153f2cea
    • Milad Fa's avatar
      PPC/s390: Allowing map word to be used for other state in GC header. · fb533e8d
      Milad Fa authored 
      Port 5e0b94c4

Original Commit Message:

    This CL adds features to pack/unpack map words.

    Currently V8 cannot store extra metadata in object headers -- because V8
    objects do not have a proper header, but only a map pointer at the start
    of the object. To store per-object metadata like marking data, a side
    table is required as the per-object metadata storage.

    This CL enables V8 to use higher unused bits in a 64-bit map word as
    per-object metadata storage. Map pointer stores come with an extra step
    to encode the metadata into the pointer (we call it "map packing").
    Map pointer loads will also remove the metadata bits as well (we call it
    "map packing").

    Since the map word is no longer a valid pointer after packing, we also
    change the tag of the packed map word to make it looks like a Smi. This
    helps various GC and barrier code to correctly skip them instead of
    blindly dereferencing this invalid pointer.

    A ninja flag `v8_enable_map_packing` is provided to turn this
    map-packing feature on and off. It is disabled by default.

    * Only works on x64 platform, with `v8_enable_pointer_compression`
      set to `false`

R=wenyu.zhao@anu.edu.au, joransiu@ca.ibm.com, junyan@redhat.com, midawson@redhat.com
BUG=
LOG=N

Change-Id: I4a13093e7b20bb38990d947c697008a920cfe715
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2821649Reviewed-by: 's avatarJunliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#73923}
      fb533e8d