Drive-by: Pointer to reference conversions and other smaller cleanups.

Change-Id: I83ed114e4b27d5986a389a9753333716b0e20524
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3133146Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76615}

This change avoid dispatching a write barrier during the atomic pause.
The dispatch can generally be triggered through pre-finalizers.

In future, further checks may be added to avoid mis-use of
pre-finalizers.

Bug: chromium:1056170, chromium:1175560
Change-Id: I119e18372633b2375f60e17b4c881f68bb20bf66
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2679685Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72560}

Adds a v8-gn.h file containing defines that are used in the
externally-visible headers files like v8.h. This must be included by
include/v8config.h which includes it if the GN flag
v8_generate_external_defines_header is on. (Currently off by default).

To enable the v8config.h file to be included without the other v8
headers (as required by cppgc), this moves it into its own header set
which sets up the include path correctly.

Also updates some headers to ensure v8config.h is included before using
externally-visible defines.

Bug: v8:11292
Change-Id: I5be634f4adfbef144bf684071461d64f1cb30899
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2608212
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72140}

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}

This also introduces CagedHeapLocalData.

Bug: chromium:1029379
Change-Id: Ice04fe5ad7daa02f17ad107e78e53bdd32479737
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2246560Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68358}

This moves from Blink:
1) implementation of the marking write barrier;
2) WriteBarrierWorklist to Marker;
3) incremental/concurrent marking options.

Bug: chromium:1056170
Change-Id: Ia3e31ffd920a99803420b1453695fe2fb8d843b8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2218064
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@{#68108}

Please take a look at tools/v8windbg/README.md for an overview of what
v8windbg can do and how it's structured. This platform-specific
debugging plugin makes use of the data provided by the V8 postmortem
debugging API in tools/debug_helper.

Note: This code began as https://github.com/billti/v8dbg and then moved
into the Edge repository, where I added features gradually and got code
reviews for individual changes. Now, taken in its entirety, it's an
obnoxiously large CL. I'm open to breaking it up into a few chunks if
that would be preferable.

Bug: v8:9376
Change-Id: I3e503de00bb1aea870ae83e9bd99e4e2eab9ef98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2031700Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#66319}