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  1. 12 Apr, 2021 1 commit
    • Wenyu Zhao's avatar
      Allowing map word to be used for other state in GC header. · 5e0b94c4
      Wenyu Zhao authored 
      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`

Bug: v8:11624
Change-Id: Ia2bdf79553945e5fc0b0874c87803d2cc733e073
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2247561Reviewed-by: 's avatarUlan Degenbaev <ulan@chromium.org>
Reviewed-by: 's avatarNico Hartmann <nicohartmann@chromium.org>
Reviewed-by: 's avatarToon Verwaest <verwaest@chromium.org>
Reviewed-by: 's avatarGeorg Neis <neis@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73915}
      5e0b94c4
  3. 06 Apr, 2021 1 commit
    • Shu-yu Guo's avatar
      Reland^2 "[ptr-cage] Rename IsolateRoot to PtrComprCageBase" · 627b6b2f
      Shu-yu Guo authored 
      This is a reland of e28dadc2

The original failure was due to a stale Win32 bot. The reland failure
was due to idempotent task deduplication returning the exact same
failure. See crbug/1196064

Original change's description:
> [ptr-cage] Rename IsolateRoot to PtrComprCageBase
>
> Currently, IsolateRoot is both the address of the Isolate root and the
> base address of the pointer compression reservation. This CL teases the
> two uses apart by renaming IsolateRoot to PtrComprCageBase.
>
> - In addition to V8_COMPRESS_POINTERS, add a
>   V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
>
> - Rename GetIsolate* helpers to GetPtrComprCageBase. When
>   V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
>   aliases to GetPtrComprCageBase.
>
> - Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
>
> Bug: v8:11460
> Change-Id: I1d715f678ce9a0b5731895612ca14f56579b1c48
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Auto-Submit: Shu-yu Guo <syg@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73790}

Bug: v8:11460
No-Try: true
Tbr: ishell@chromium.org
Tbr: rmcilroy@chromium.org
Change-Id: Id69311cf3267ebe1297fff159de0be48b15b65a3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806546Reviewed-by: 's avatarShu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73795}
      627b6b2f
  5. 05 Apr, 2021 4 commits
    • Shu-yu Guo's avatar
      Revert "Reland "[ptr-cage] Rename IsolateRoot to PtrComprCageBase"" · 562c4251
      Shu-yu Guo authored 
      This reverts commit 15c78b45.

Reason for revert: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32/32277/overview

Original change's description:
> Reland "[ptr-cage] Rename IsolateRoot to PtrComprCageBase"
>
> This is a reland of e28dadc2
>
> Relanding to see if Win32 rel failures from
> https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32/32275/overview
> were infra flakes. Could not repro on try bots.
>
> Original change's description:
> > [ptr-cage] Rename IsolateRoot to PtrComprCageBase
> >
> > Currently, IsolateRoot is both the address of the Isolate root and the
> > base address of the pointer compression reservation. This CL teases the
> > two uses apart by renaming IsolateRoot to PtrComprCageBase.
> >
> > - In addition to V8_COMPRESS_POINTERS, add a
> >   V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
> >
> > - Rename GetIsolate* helpers to GetPtrComprCageBase. When
> >   V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
> >   aliases to GetPtrComprCageBase.
> >
> > - Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
> >
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
> > Reviewed-by: Igor Sheludko <ishell@chromium.org>
> > Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
>
> No-Try: true
> Bug: v8:11460
> Tbr: ishell@chromium.org
> Tbr: rmcilroy@chromium.org
> Change-Id: I0a8c3a48999d6737c8c64d2c2703607f14f3fdd0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806169
> Reviewed-by: Shu-yu Guo <syg@chromium.org>
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73792}

Bug: v8:11460
Change-Id: Ifee92d622c43a91c15f45ef94ff739237bd2024b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806545
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Reviewed-by: 's avatarShu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73793}
      562c4251
    • Shu-yu Guo's avatar
      Reland "[ptr-cage] Rename IsolateRoot to PtrComprCageBase" · 15c78b45
      Shu-yu Guo authored 
      This is a reland of e28dadc2

Relanding to see if Win32 rel failures from
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32/32275/overview
were infra flakes. Could not repro on try bots.

Original change's description:
> [ptr-cage] Rename IsolateRoot to PtrComprCageBase
>
> Currently, IsolateRoot is both the address of the Isolate root and the
> base address of the pointer compression reservation. This CL teases the
> two uses apart by renaming IsolateRoot to PtrComprCageBase.
>
> - In addition to V8_COMPRESS_POINTERS, add a
>   V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
>
> - Rename GetIsolate* helpers to GetPtrComprCageBase. When
>   V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
>   aliases to GetPtrComprCageBase.
>
> - Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
>
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>

No-Try: true
Bug: v8:11460
Tbr: ishell@chromium.org
Tbr: rmcilroy@chromium.org
Change-Id: I0a8c3a48999d6737c8c64d2c2703607f14f3fdd0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806169Reviewed-by: 's avatarShu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73792}
      15c78b45
    • Francis McCabe's avatar
      Revert "[ptr-cage] Rename IsolateRoot to PtrComprCageBase" · 07a9ff4d
      Francis McCabe authored 
      This reverts commit e28dadc2.

Reason for revert: failed test262 tests;; see https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32/32275/steps?succeeded=true&debug=false

Original change's description:
> [ptr-cage] Rename IsolateRoot to PtrComprCageBase
>
> Currently, IsolateRoot is both the address of the Isolate root and the
> base address of the pointer compression reservation. This CL teases the
> two uses apart by renaming IsolateRoot to PtrComprCageBase.
>
> - In addition to V8_COMPRESS_POINTERS, add a
>   V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
>
> - Rename GetIsolate* helpers to GetPtrComprCageBase. When
>   V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
>   aliases to GetPtrComprCageBase.
>
> - Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
>
> Bug: v8:11460
> Change-Id: I1d715f678ce9a0b5731895612ca14f56579b1c48
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Auto-Submit: Shu-yu Guo <syg@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73790}

Bug: v8:11460
Change-Id: I19d0e28194fcdb28e89f129a7694ca3fe29fa17a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806168
Auto-Submit: Francis McCabe <fgm@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#73791}
      07a9ff4d
    • Shu-yu Guo's avatar
      [ptr-cage] Rename IsolateRoot to PtrComprCageBase · e28dadc2
      Shu-yu Guo authored 
      Currently, IsolateRoot is both the address of the Isolate root and the
base address of the pointer compression reservation. This CL teases the
two uses apart by renaming IsolateRoot to PtrComprCageBase.

- In addition to V8_COMPRESS_POINTERS, add a
  V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).

- Rename GetIsolate* helpers to GetPtrComprCageBase. When
  V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
  aliases to GetPtrComprCageBase.

- Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.

Bug: v8:11460
Change-Id: I1d715f678ce9a0b5731895612ca14f56579b1c48
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Reviewed-by: 's avatarIgor Sheludko <ishell@chromium.org>
Reviewed-by: 's avatarRoss McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73790}
      e28dadc2
  7. 07 Oct, 2020 1 commit
  9. 11 Sep, 2020 1 commit
  11. 13 Aug, 2020 1 commit
    • Leszek Swirski's avatar
      [runtime] Compress the off-heap string table · 279bd3e1
      Leszek Swirski authored 
      Rather than an Object array, use a Tagged_t array to store the
elements of the off-heap string table. This matches the old on-heap
string table's behaviour, and recovers memory regressions from that
work.

To be able to do this, this also introduces a new slot type,
OffHeapObjectSlot. This is because CompressedObjectSlot assumes that
the slot is on-heap, and that it can mask the slot location to
recover the isolate root. OffHeapObjectSlot doesn't define an
operator*, and instead provides a `load(const Isolate*)` method.
The other slots also gain this method so that they can use it in
slot-templated functions. Also, the RootVisitor gains an
OffHeapObjectSlot overload, which is UNREACHABLE by default and only
needs to be defined by visitors that can access the string table.

As a drive-by, fix some non-atomic accesses to the off-heap string
table, also using the new slot.

Bug: chromium:1109553
Bug: chromium:1115116
Bug: chromium:1115559
Bug: chromium:1115683
Change-Id: I819ed7bf820e9ef98ad5d5f9d0d592efbb6f5aa6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2352489
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: 's avatarJakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarUlan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69381}
      279bd3e1
  13. 10 Feb, 2020 1 commit
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  27. 27 Feb, 2019 1 commit
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  37. 26 Dec, 2018 1 commit
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