Adds getters for GC phases to be used by advanced embedders to ensure
and check consistency conditions as needed.

Bug: chromium:1056170
Change-Id: Ia0b219f838bf31f0edbfe40585b95bb5eafa734d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2658328Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72430}

This CL adds tracing scopes for the various cppgc classes.
Scopes use TRACE_EVENT_BEGIN and TRACE_EVENT_END macros to report trace
events. To do so they need to include trace-event.h. For unified heap
builds, trace-event.h forwards to v8's src/tracing/trace-event.h. For
other builds, trace-event.h provides a subset of
src/tracing/trace-event.h that covers just the parts used by cppgc.

This CL covers what we need for traces and blink gc metrics (up to
renaming events from BlinkGC.* to CppGC.*). UMA and UKM are not yet
handled.

Bug: chromium:1056170
Change-Id: Id92e84b27259ff0aadae7692f3d79d30896fb8e7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2540548
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71284}

This is a reland of 90ea9b35

Original change's description:
> cppgc: Port backing store compaction.
>
> This CL ports the existing backing store compaction algorithm from
> blink. It does not attempt to improve on the existing algorithm.
>
> Currently only unified heap uses the compaction implementation. It is
> never triggered through standalone GCs.
>
> The compaction implementation resides within an internal "subtle" namespace.
>
> Bug: v8:10990
> Change-Id: I4aa781db1b711e7aafc34234c4fb142de84394d7
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2485228
> 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@{#70714}

Bug: v8:10990
Change-Id: I527c2042a26648d058bfe4d355527cce9a3eeadc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2492331
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70736}

This reverts commit 90ea9b35.

Reason for revert: https://ci.chromium.org/p/v8/builders/ci/V8%20Mac64%20-%20debug/31274?

Original change's description:
> cppgc: Port backing store compaction.
>
> This CL ports the existing backing store compaction algorithm from
> blink. It does not attempt to improve on the existing algorithm.
>
> Currently only unified heap uses the compaction implementation. It is
> never triggered through standalone GCs.
>
> The compaction implementation resides within an internal "subtle" namespace.
>
> Bug: v8:10990
> Change-Id: I4aa781db1b711e7aafc34234c4fb142de84394d7
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2485228
> 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@{#70714}

TBR=mlippautz@chromium.org,bikineev@chromium.org,omerkatz@chromium.org

Change-Id: Iadae1ee0c6c0400f0e1a0a3805be5316a1d4b979
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10990
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2492330Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70716}

This CL ports the existing backing store compaction algorithm from
blink. It does not attempt to improve on the existing algorithm.

Currently only unified heap uses the compaction implementation. It is
never triggered through standalone GCs.

The compaction implementation resides within an internal "subtle" namespace.

Bug: v8:10990
Change-Id: I4aa781db1b711e7aafc34234c4fb142de84394d7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2485228
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@{#70714}

Heap growing estimates when to start  incremental gc such that it
will finish when we are expecting to finalize (i.e. when an atomic
gc would be triggered).
There is also a minimum ratio between limit for atomic gc and limit
for incremental gc, to guarantee that incremental gc get's some time to
run even with the application rarely allocates.

This is a continuation of:
https://chromium-review.googlesource.com/c/v8/v8/+/2377691

Bug: chromium:1056170
Change-Id: I8c87e98d60b6f8b5748558771a236f15385f7858
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2381454Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69630}

This adds the following things:
- age table for 4K regions;
- generational barrier for mixed 4K regions;
- unmarking for major collections;
- young generation flags.

Bug: chromium:1029379
Change-Id: Ief1229f0dac5f90c5f06d3168c8ffb4b7d1f1b53
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2246566
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68379}

Adds allocation-based heap growing strategy that triggers GC based on
some limit. The limit is computed based on previous live memory and a
constant growing factor.

For invoking GC, we support two modes: with and without conservative
stack scanning. Without conservative stack scanning, an invoker makes
sure that we schedule a GC without stack using the existing platform.

Bug: chromium:1056170
Change-Id: I1808aeb5806a6ddd5501b556d6b6b129a85b9cda
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2228887Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68235}