This adds support for custom weak callbacks through static callbacks and
instance methods.

Bug: chromium:1056170
Change-Id: Ie4bd32539e0d933b192f07edb2d45e0070c2128d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2148784
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67167}

CrossThreadPersistent and friends are the followup.

Bug: chromium:1056170
Change-Id: Ide910062d80952da73b922398c281162b1861f47
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2144957
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: 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@{#67153}

AIX default page size is 4096 bytes hence
PlatformUsesGuardPages returns true. Power Linux however
has a default page size of 65536 bytes and the above function
is expected to return false. More info is available
at https://crrev.com/c/2144060.

Change-Id: I35a13ada5bd1b18729cfa039a0bc699a409fbc2c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2147634Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#67134}

A few notes:
1) Oilpan is a generic library, meaning that it can work with arbitrary
user types. The library is split in type-aware (include/) and
type-erased (src/) parts. The former comprises a lot of code that still
needs to be defended with dchecks;
2) Macros are prefixed with CPPGC_, so that they don't clash in the user
code with similar macros from other libraries;
3) The macros simply forward requests to V8 so that dcheck handlers can
be configured uniformly;
4) The CL doesn't contain CHECK_EQ and friends, but they can be added
later if needed.

Bug: chromium:1056170
Change-Id: I68e6f663247705233eaf030384164d81e53071e1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2148774
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: 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@{#67129}

This CL adds:
- Declaring and invoking prefinalizers
- NoAllocationScope

Bug: chromium:1056170
Change-Id: Ib0f688fa4a8bb5fde44b36597ce2d6d2664fdff5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2139588
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67125}

This is a port of src/components/gc that was added recently.

Differences:
- Added back bucketing to the page pool, as that guarantees that
  arenas used for specific types do not have their pages used by other
  arenas.
- Replaced base::flat_map with std::map. This may cause performance
  regressions when using PageMemoryRegionTree in hot paths. A
  vector-like representation may be used to fix such a regression

This reverts commit a056cea5.

Bug: chromium:1056170
Change-Id: Iffb8b0d91c8cca1815d7a1cda9486e7716aea75f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2144060
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67117}

Change the unittests Isolate mixin to create one Isolate per test,
rather than one per test suite. We usually run these tests independently
in separate processes anyway, so this shouldn't affect normal test
execution, but it will avoid Isolate state leaking across tests when
running the unittests binary directly.

Take this opportunity to also clean up the mixins, changing counter
initialization and forcing pointer compression into template traits.

Bug: v8:10142
Change-Id: If92046f9c6f2056252d099faed04d97844ef7319
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2143818Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67110}

Provides the infrastructure to register weak callbacks for
WeakMember<T> through visitor. The WeakCallbackInfo broker is used to
query objects for liveness. In a future CL the same broker object is
passed to custom weak callbacks.

Change-Id: I8b5a66354e0e457521989d40ae64a9558c339503
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2142265
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67109}

This reverts commit 3e1c7040.

Reason for revert: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20TSAN%20-%20concurrent%20marking/12665

Original change's description:
> Reland "cppgc: Add page memory allocation backend"
> 
> This is a port of src/components/gc that was added recently.
> 
> Differences:
> - Added back bucketing to the page pool, as that guarantees that
>   arenas used for specific types do not have their pages used by other
>   arenas.
> - Replaced base::flat_map with std::map. This may cause performance
>   regressions when using PageMemoryRegionTree in hot paths. A
>   vector-like representation may be used to fix such a regression
> 
> This reverts commit 656c68a7.
> 
> Bug: chromium:1056170
> Change-Id: I638183c944255ebcaab47d2b94b1980d54479746
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2143814
> Reviewed-by: Maya Lekova <mslekova@chromium.org>
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#67080}

TBR=mlippautz@chromium.org,mslekova@chromium.org

Change-Id: I04b048dd979c32e9275c972307796d5f75865037
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2144114Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67084}

This is a port of src/components/gc that was added recently.

Differences:
- Added back bucketing to the page pool, as that guarantees that
  arenas used for specific types do not have their pages used by other
  arenas.
- Replaced base::flat_map with std::map. This may cause performance
  regressions when using PageMemoryRegionTree in hot paths. A
  vector-like representation may be used to fix such a regression

This reverts commit 656c68a7.

Bug: chromium:1056170
Change-Id: I638183c944255ebcaab47d2b94b1980d54479746
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2143814Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67080}

GetHeapFromPayload returned the page header address instead of the
value of the first field of the header.

Bug: chromium:1056170
Change-Id: I4de5be975accced32460d6fab91543e6a5b07ba0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2143825
Auto-Submit: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67079}

Fix off-thread space merging unit tests, by

  a) Doing a GC on each test teardown (avoiding leaking GC state between
     tests), and
  b) Removing the AllocationStep when merging, which could cause a
     deadlock if incremental marking triggered a free-list refill.

Bug: v8:10142
Change-Id: Id2670115f96ab3b13613ea357bd44a639d0151e1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2142260
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67077}

This CL provides a basic allocator that allocates normal-sized objects
on pages without ever reusing them. This allows for already using the
backref from page to heap which is used in some critical places
(pre-finalizers, write barrier, Persistent).

Bug: chromium:1056170
Change-Id: Ifada9b7e984827906c267d1a3a521576587feaeb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2141736
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67076}

This reverts commit d4056c61.

Reason for revert: Fails on GCC, please check https://ci.chromium.org/p/v8/builders/ci/V8%20Linux%20gcc/6184

Original change's description:
> cppgc: Add page memory allocation backend
> 
> This is a port of src/components/gc that was added recently.
> 
> Differences:
> - Added back bucketing to the page pool, as that guarantees that
>   arenas used for specific types do not have their pages used by other
>   arenas.
> - Replaced base::flat_map with std::map. This may cause performance
>   regressions when using PageMemoryRegionTree in hot paths. A
>   vector-like representation may be used to fix such a regression
> 
> Bug: chromium:1056170
> Change-Id: I03e3abe55faf7bb50c8011dafc23396889bf66db
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2139586
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#67073}

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

Change-Id: I1e421898bb8a08f32d8eb2355ed547e0ee38b429
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2140949Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67074}

This is a port of src/components/gc that was added recently.

Differences:
- Added back bucketing to the page pool, as that guarantees that
  arenas used for specific types do not have their pages used by other
  arenas.
- Replaced base::flat_map with std::map. This may cause performance
  regressions when using PageMemoryRegionTree in hot paths. A
  vector-like representation may be used to fix such a regression

Bug: chromium:1056170
Change-Id: I03e3abe55faf7bb50c8011dafc23396889bf66db
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2139586
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67073}

This change comprises a few tiny changes wrt Member:
1) Move member policies to a separate file so that some of them
(CheckingPolicy) can be reused by Persistent;
2) SFINAE out incompatible pointers from heterogeneous ctor/asgnmt;
3) Rename kMemberSentinel to kSentinelPointer.

Bug: chromium:1056170
Change-Id: I4482998e6ba61005a5d0861dcae9fab2aa43702c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2139587Reviewed-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@{#67061}

Bug: chromium:1056170
Change-Id: I98bbff8d2938c6b34fe2c358d504ba6211ec8b54
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2140931Reviewed-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@{#67054}

Headers containing only implementation details are better to stay in a
separate dir to indicate the user that they shouldn't be included.

Bug: chromium:1056170
Change-Id: I10f84ddf709b146396aadc820ec33bc6a49b2dac
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2139585Reviewed-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@{#67050}

Neither Member, nor GarbageCollected objects (and friends) should be
allocated on the stack. Create a special test fixture that allows for
writing idiomatic unit tests that depend on allocation but do not pull
in garbage collection.

Bug: chromium:1056170
Change-Id: I4118201a51658f7247412434a867d35c91299439
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2139583Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67046}

This CL adds the necessary traits to dispatch from Member through a
visitor implementation for GarabgeCollected and GarbageCollectedMixin.

Bug: chromium:1056170
Change-Id: I12680335044aaa842639fb5e8f9a3ac61587f51a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2138431Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67041}

Assumes that (is_clang = false && is_win) => Windows native (MSVC).

Cross-compile builds will use clang and not the native tools and thus
not fall into this category.

This CL adds x86 and x64 MASM trampolines that can be used with the
native Windows toolchain (ml.exe, ml64.exe), when using is_clang =
false.

This reverts commit 8e4a5e97.

Bug: chromium:1056170
Change-Id: I7204f15898ec5eddcc5892d4d08266a69d84ab85
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2139211
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67036}

The dummy sweeping algorithm didn't actually remove objects from the
internal list.

Bug: chromium:1056170
Change-Id: I29a93a2ac7fc36ca95125805076ff5ce257de8a4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2138433
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67033}

With this change we support allocation of objects and keeping them
alive via conservative stack scan.

This reverts commit 2b047a58.

Change-Id: Iac1913e7ef0556c28399509a160777a89e60150c
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2137402
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67016}

This reverts commit 44a1ed8f.

Reason for revert: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux%20gcc/6124?

Original change's description:
> cppgc: Integrate conservative stack scan into GC
> 
> With this change we support allocation of objects and keeping them alive via
> conservative stack scan.
> 
> Change-Id: Id94d7ced503ad0b1378643e0c13c2a8b65ad2327
> Bug: chromium:1056170
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2135729
> Reviewed-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@{#67008}

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

Change-Id: I71bf7a9b7f54f0ec8d64b1b1781699adb0feb138
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2137401Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67009}

With this change we support allocation of objects and keeping them alive via
conservative stack scan.

Change-Id: Id94d7ced503ad0b1378643e0c13c2a8b65ad2327
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2135729Reviewed-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@{#67008}

We cannot rely on the clang compiler to generate the trampoline entry
and the right mangling because `__attribute__((naked))` does not
prevent clang from generating TSAN function entry stub
(`__tsan_func_entry`). Even with `__attribute__((no_sanitize_thread)`
annotation clang generates the entry stub.

Upstream bug: https://bugs.llvm.org/show_bug.cgi?id=45400

Bug: chromium:1056170
Change-Id: I7a2063d7d205ee071e6a41ce4d9cb2d8d6423987
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2132797Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66976}

SourceLocation is needed to track Persistents.

Bug: chromium:1056170
Change-Id: I4d5cf151a4d27b4c29582ff8195cdcb7453afe1c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2132790
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66974}

Tbr: bikineev@chromium.org
No-try: true
Bug: chromium:1056170
Change-Id: I4872b617b038bc647543a3dd5a435ad82c7291ba
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2132792Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66960}

This CL introduces
 - GarbageCollectedMixin
 - IsGarbageCollectedMixinType
 - HeapObjectHeaderFor (utility method to get correct header for mixins)

Bug: chromium:1056170
Change-Id: I48c2c02fa57487824130ea3620c975a0785075e4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2130275
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66953}

The tests using the recursive function were broken on non-clang builds
as GCC is able to agressively the function in question and proof that
parameters are not actually needed.

Bug: chromium:1056170
Change-Id: Iacbff766ca9d300c9ae5d16394e205b1883609eb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2130274
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66952}

This CL introduces
 - Member
 - WeakMember
 - UntracedMember
interfaces. Remaining work is to add pointer verifier and write barrier
implementation.

Bug: chromium:1056170
Change-Id: Iddb8e4d002db0b1d1652f2946ddfa08a98a889c7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2124323
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66927}

Pure refactoring. The re-organization allows to easily
add more platforms.

Bug: chromium:1056170
Change-Id: Ia191c37a1dabff6952414c5314beeeae881713b7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2129636Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66924}

This tests that the stack doesn't get misaligned after asm trampolines.
x86 and x64 psABI requires the stack to be 16 bytes aligned.

Bug: chromium:1056170
Change-Id: I73e7100806c6ecf3f5e884a121a15bcc384d8011
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2128048Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Reviewed-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@{#66922}

Adds support for conservative stack scanning on x64. The trampolines
saving callee-saved registers are compiled using clang (non-Windows)
and MASM (Windows). This is using the default toolchain for assembly
in Chromium/V8.

This differs from Oilpan in Chromium where x86 and x64 are compiled
using NASM [1]. V8 does not yet require this dependency and building
the trampolines natively avoids it. (NASM also requires separate
blocks for x64 Windows and non-Windows.) On non-x86/x64 platforms
Chromium also uses clang, so there's little benefit in keeping the
dependency.

The trampolines are tested when building with clang.

Other platforms follow in separate CLs.

[1] https://source.chromium.org/chromium/chromium/src/+/master:third_party/blink/renderer/platform/heap/asm/SaveRegisters_x86.asm

Change-Id: Ice2e23e44391aa94147abe75ee0b5afac458b8f8
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2124319
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66913}

iOS does not support death tests.

Bug: v8:10360
Change-Id: Ia86553d53eee811e5521c093fd034115a9d01750
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2128046
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66912}

This CL adds basic infrastructure for:
- MakeGarbageCollected
- GarbageCollected and related type traits
- Heap (API / internal)
- Basic allocation based on malloc
- CollectGarbage without marking

This allows for allocation and reclamation through an explicit GC
call. No objects are held alive from any source (stack, globals,
refs), yet.

The exact wiring of platform is future work.

Change-Id: I81b7c0ba7b525188f8c0bf9de3b7af35d34322af
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2120538
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66887}

std::atomic loads are marked as nodiscard on MSVC. Fix the warning by
feeding the load into the USE() macro.

Bug: chromium:1056170
Change-Id: I72ca42d42d268c4b961d96618250229a53709472
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2120543Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66866}

This adds HeapObjectHeader, a meta object that is put in front of
every managed object. HeapObjectHeader provides accessors for:
1. GCInfoIndex
2. In construction bit
3. size
4. Mark bit

Meta info is distributed among two uint16_t fields as (1.,2.) and
(3.,4.). This is convenient as the non-bit accessors (size,
GCInfoIndex) are constant during marking.

Object layout see heap-object-header.h.

Note: The current implementation does not bypass ASAN poisoning and
assumes an unpoisoned header whenever performing an access.

Bug: chromium:1056170
Change-Id: I753f15467ed5c2b22b47e64d3aa5a3c1baddf8e1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2116031
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66861}

Add LocalHandleScope to allow for local handles in LocalHeaps
(background threads). This class is similar to HandleScope which still
needs to be used on the main thread. When performing a GC, the main
thread halts all background threads at a safepoint such that it can
safely iterate their roots.

Bug: v8:10315
Change-Id: Id8f5d54cc2535e004081ccdef15dc03a39b2d0f0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2111218
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66853}

GCInfo and its related infrastructure is used to record information
about types. Currently, we store finalization and vtable information.
Future changes will introduce naming and tracing, similar to Oilpan in
Blink.

Information is stored in a process-wide global table that is
maintained at runtime. For static builds such information can be
recorded in the binary without the runtime overhead which is future
work.

This ports `third_party/blink/renderer/platform/heap/gc_info.{h,cc}`
on a semantic level. In addition to adjusting to V8's needs, we also
re-commit the already filled parts of the info table as read-only when
possible, making it harder to override type information.

Bug: chromium:1056170
Change-Id: Ib01eb24e6f8a94a4a647efde7af37689f8c20ba2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2111214
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66847}