The TraceTrait<T> checks whether T is a mixin to decide whether we can
use the fast (arithmetic) or slow (bitmap) method to look up the HoH.
Before this CL, the mixin application would also be considered as a
mixin because the marker is present, resulting in all cases going
through the object start bitmap.
The initial intention was to use the arithmetic for the mixin
applications as those inherit from GCed.
Bug: chromium:1056170
Change-Id: Ib0ba82a8f98e0481d2879ebacc1ca9bd9e675858
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2643395
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72262}
This CL removes the GetTraceDescriptor virtual call from garbage
collected mixins and replaces it with querying the object start
bitmap.
The CL also removes the mixin macros which are now no longer needed.
Bug: chromium:1056170
Change-Id: I27ed299f93025d09a3bb3f0d17b14bed3c200565
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2287508
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68787}
Unified heap support in V8 requires having another (at least internal)
heap that implements a unfied garbage collection strategy. This will
not re-use the already existing cppgc::Heap because there should be no
way in creating such a heap externally or scheduling stand-alone
garbage collections.
In order to have a common token, this CL introduces AllocationHandle
which can be passed to MakeGarbageCollected to allocate C++ objects.
V8 (soon) and the stand-alone heap both have methods to retrieve such
a handle.
This works around a problem with creating diamond class hierarchies
when a base class would be exposed on the public API level.
Fast paths for Blink are still possible because allocation handles can
be cached the same way (e.g. global, or TLS) as a heap can be cached.
Tbr: yangguo@chromium.org
Bug: chromium:1056170
Change-Id: I8e9472a2c24ef82d1178953e8429b1fd8a2344bc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2238027
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68310}
This is needed to trace objects found durinbg stack scanning.
Bug: chromium:1056170
Change-Id: I1280d98f2fe69281c514b3a7d4a57f909a2eed96
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2190425
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67788}
