After a series of CLs per component, this removes all remaining NOLINT
annotations that my script identified as not needed (because removing
them does not cause a presubmit error).

R=mlippautz@chromium.org, jkummerow@chromium.org, leszeks@chromium.org
R=cbruni@chromium.org

Bug: v8:11879
Change-Id: Ia403c23588a0c2871b987931f6c26f85821e9e9c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2972733Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75296}

... behind the v8_enable_external_code_space build flag.

This is a first CL in a row of CLs that will make CodeDataContainer
the only type of objects that could contain references to Code objects
(besides the Code objects embedded into the generated code).
Eventually these changes will allow us to move Code space out of the V8
heap cage.

This CL adds |code| field to ensure that CodeDataContainer keeps the
respective Code object alive and |code_entry_point| field that contains
cached value of the code().InstructionStart().

Bug: v8:11880
Change-Id: Ie7ce75667d8da306797d203691b429671bc4530d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2964093
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75179}

Change-Id: I4a30e0f01e35eb0824f5abeec62d55d62970b59f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2910781Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75016}

We used to recompile WasmCapiCallWrappers whenever they were
needed, but never garbage-collected them, which caused a memory
leak when many short-lived instances of the same module were
created. This patch makes the wrappers cacheable and caches them,
which avoids both repeated compilation effort and the unbounded
memory growth.
Drive-by cleanup: unify WasmCapiFunctionData with the other
Wasm*FunctionData classes by making it inherit from WasmFunctionData.

Bug: v8:11774
Change-Id: Ia0c0d76be2938dc7bebfdc845f4a1cfeafef4a70
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2905605
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74682}

By (mostly) unifying the different kinds of WasmFunctionData, and
precomputing and caching what we can, we can reduce the amount of
work that has to be done for each call.
We still have to store the current instance for JS function calls;
that may be eliminatable in the future.
WasmCapiFunctions are not included in the refactoring yet.

Bug: v8:7748,v8:9495
Change-Id: Ie6839153153d5854670cd01bc77a86111c1f68d2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2856543
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74287}

This is a reland of c83c9590

Changes since revert: nothing, issue was crbug.com/v8/11666

Original change's description:
> [ic] Add a new MegaDOM IC
>
> This patch implements the MegaDOM IC setup and access. A new MegaDOM
> IC state indicates that we've seen only DOM accessors at this access
> site.
>
> This CL only adds support for DOM getters in LoadIC, other kinds of
> access will be added in follow on CLs.
>
> Still remaining TODO before shipping:
> 1. Have a mechanism to invalidate the protector
> 2. Have a mechanism to find the accessors that aren't overloaded
> 3. Use a new builtin to miss to runtime on access check failure
>
> Change-Id: Ie12efe5e9fa284f023043b996d61e7d74e710ee2
> Bug: v8:11321
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2618239
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Reviewed-by: Camillo Bruni <cbruni@chromium.org>
> Reviewed-by: Dan Elphick <delphick@chromium.org>
> Reviewed-by: Mythri Alle <mythria@chromium.org>
> Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73733}

Bug: v8:11321
Change-Id: I2bec54465542b5b40c42adb6eb12b6ce72cce5bd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2794439Reviewed-by: Dan Elphick <delphick@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74056}

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: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73915}

This reverts commit c83c9590.

Reason for revert: Speculatively reverting for a failure on Arm GC stress bot - https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Arm%20GC%20Stress/b8851256837192083520/overview

Original change's description:
> [ic] Add a new MegaDOM IC
>
> This patch implements the MegaDOM IC setup and access. A new MegaDOM
> IC state indicates that we've seen only DOM accessors at this access
> site.
>
> This CL only adds support for DOM getters in LoadIC, other kinds of
> access will be added in follow on CLs.
>
> Still remaining TODO before shipping:
> 1. Have a mechanism to invalidate the protector
> 2. Have a mechanism to find the accessors that aren't overloaded
> 3. Use a new builtin to miss to runtime on access check failure
>
> Change-Id: Ie12efe5e9fa284f023043b996d61e7d74e710ee2
> Bug: v8:11321
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2618239
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Reviewed-by: Camillo Bruni <cbruni@chromium.org>
> Reviewed-by: Dan Elphick <delphick@chromium.org>
> Reviewed-by: Mythri Alle <mythria@chromium.org>
> Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73733}

Bug: v8:11321
Change-Id: Ib6a55796f2a3c345d4923f9eaa215a6ff55ed15b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2794437
Auto-Submit: Maya Lekova <mslekova@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@{#73734}

This patch implements the MegaDOM IC setup and access. A new MegaDOM
IC state indicates that we've seen only DOM accessors at this access
site.

This CL only adds support for DOM getters in LoadIC, other kinds of
access will be added in follow on CLs.

Still remaining TODO before shipping:
1. Have a mechanism to invalidate the protector
2. Have a mechanism to find the accessors that aren't overloaded
3. Use a new builtin to miss to runtime on access check failure

Change-Id: Ie12efe5e9fa284f023043b996d61e7d74e710ee2
Bug: v8:11321
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2618239Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73733}

This is a reland of 80f5dfda. A condition
in pipeline.cc was inverted, which lead to a CSA verifier error.

Original change's description:
> [no-wasm] Exclude src/wasm from compilation
>
> This is the biggest chunk, including
> - all of src/wasm,
> - torque file for wasm objects,
> - torque file for wasm builtins,
> - wasm builtins,
> - wasm runtime functions,
> - int64 lowering,
> - simd scala lowering,
> - WasmGraphBuilder (TF graph construction for wasm),
> - wasm frame types,
> - wasm interrupts,
> - the JSWasmCall opcode,
> - wasm backing store allocation.
>
> Those components are all recursively entangled, so I found no way to
> split this change up further.
>
> Some includes that were recursively included by wasm headers needed to
> be added explicitly now.
>
> backing-store-unittest.cc is renamed to wasm-backing-store-unittest.cc
> because it only tests wasm backing stores. This file is excluded from
> no-wasm builds then.
>
> R=jkummerow@chromium.org, jgruber@chromium.org, mlippautz@chromium.org, petermarshall@chromium.org
>
> Bug: v8:11238
> Change-Id: I7558f2d12d2dd6c65128c4de7b79173668c80b2b
> Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2742955
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Peter Marshall <petermarshall@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73344}

TBR=jgruber@chromium.org

Bug: v8:11238
Change-Id: I20bd2847a59c68738b5a336cd42582b7b1499585
Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
Cq-Include-Trybots: luci.v8.try:v8_linux_verify_csa_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_linux64_verify_csa_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2752867Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73348}

This reverts commit 80f5dfda.

Reason for revert: Fails CSA verification: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux%20-%20verify%20csa/21766/overview

Original change's description:
> [no-wasm] Exclude src/wasm from compilation
>
> This is the biggest chunk, including
> - all of src/wasm,
> - torque file for wasm objects,
> - torque file for wasm builtins,
> - wasm builtins,
> - wasm runtime functions,
> - int64 lowering,
> - simd scala lowering,
> - WasmGraphBuilder (TF graph construction for wasm),
> - wasm frame types,
> - wasm interrupts,
> - the JSWasmCall opcode,
> - wasm backing store allocation.
>
> Those components are all recursively entangled, so I found no way to
> split this change up further.
>
> Some includes that were recursively included by wasm headers needed to
> be added explicitly now.
>
> backing-store-unittest.cc is renamed to wasm-backing-store-unittest.cc
> because it only tests wasm backing stores. This file is excluded from
> no-wasm builds then.
>
> R=​jkummerow@chromium.org, jgruber@chromium.org, mlippautz@chromium.org, petermarshall@chromium.org
>
> Bug: v8:11238
> Change-Id: I7558f2d12d2dd6c65128c4de7b79173668c80b2b
> Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2742955
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Peter Marshall <petermarshall@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73344}

Bug: v8:11238
Change-Id: I93672002c1faa36bb0bb5b4a9cc2032ee2ccd814
Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2752866
Auto-Submit: Clemens Backes <clemensb@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@{#73346}

This is the biggest chunk, including
- all of src/wasm,
- torque file for wasm objects,
- torque file for wasm builtins,
- wasm builtins,
- wasm runtime functions,
- int64 lowering,
- simd scala lowering,
- WasmGraphBuilder (TF graph construction for wasm),
- wasm frame types,
- wasm interrupts,
- the JSWasmCall opcode,
- wasm backing store allocation.

Those components are all recursively entangled, so I found no way to
split this change up further.

Some includes that were recursively included by wasm headers needed to
be added explicitly now.

backing-store-unittest.cc is renamed to wasm-backing-store-unittest.cc
because it only tests wasm backing stores. This file is excluded from
no-wasm builds then.

R=jkummerow@chromium.org, jgruber@chromium.org, mlippautz@chromium.org, petermarshall@chromium.org

Bug: v8:11238
Change-Id: I7558f2d12d2dd6c65128c4de7b79173668c80b2b
Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2742955
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73344}

Change-Id: Ib54d5abad3e67f74d1930af135778e1f201ba28f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2712964
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73050}

This is a reland of
https://chromium-review.googlesource.com/c/v8/v8/+/2688058

This CL is part of a series that adds the C++ implementation of
SwissNameDictionary, a deterministic property backing store based on
Swiss Tables.

This CL adds the initialization code, factory functions and a
canonical SwissNameDictionary plus all helpers required for that.

Bug: v8:11388
Change-Id: I9cf66a3fa755288f7730f55abfb6e6cea82f6b03
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2703653
Commit-Queue: Frank Emrich <emrich@google.com>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72857}

This reverts commit 2f8a7561.

Reason for revert: Speculative revert, lots of segfaults on Arm:
https://ci.chromium.org/p/v8/builders/ci/V8%20Arm%20-%20debug/17781

Original change's description:
> [dict-proto] C++ implementation of SwissNameDictionary, pt. 3
>
> This CL is part of a series that adds the C++ implementation of
> SwissNameDictionary, a deterministic property backing store based on
> Swiss Tables.
>
> This CL adds the initialization code, factory functions and a
> canonical SwissNameDictionary plus all helpers required for that.
>
> Bug: v8:11388
> Change-Id: I6bb92740afefc7d05433cfa62023e6da5e8213c7
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2688058
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Marja Hölttä <marja@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Frank Emrich <emrich@google.com>
> Cr-Commit-Position: refs/heads/master@{#72824}

Bug: v8:11388
Change-Id: Ia5dae584b0fb452b12c5d64ee63ffa418c83f91b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2698758
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72829}

This CL is part of a series that adds the C++ implementation of
SwissNameDictionary, a deterministic property backing store based on
Swiss Tables.

This CL adds the initialization code, factory functions and a
canonical SwissNameDictionary plus all helpers required for that.

Bug: v8:11388
Change-Id: I6bb92740afefc7d05433cfa62023e6da5e8213c7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2688058Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Frank Emrich <emrich@google.com>
Cr-Commit-Position: refs/heads/master@{#72824}

This CL is part of a series that adds the C++ implementation of
SwissNameDictionary, a deterministic property backing store based on
Swiss Tables.

This CL contains most of the boilerplate code for introducing a new
instance type.

Bug: v8:11388
Change-Id: Id263b8138a8ce4b465fb28d968223d2e1aaf05a4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2672030Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Frank Emrich <emrich@google.com>
Cr-Commit-Position: refs/heads/master@{#72582}

This is a reland of b77deeca

Changes compared to original: Add explicit narrowing casts in tests
for MSVC.

Original change's description:
> [wasm-gc] Remove abstract rtts
>
> In the latest wasm-gc spec, rtts of abstract types are no longer
> allowed. Consequently, canonical rtts of concrete types always have
> a depth of 0.
>
> Changes:
> - Change the immediate argument of rtts to a type index over a heap
>   type. Abstract it with TypeIndexImmediate in function body decoding.
>   This affects:
>   value_type.h, read_value_type(), decoding of relevant opcodes,
>   wasm subtyping, WasmInitExpr, consume_init_expr(), and
>   wasm-module-builder.cc.
> - In function-body-decoder-impl.h, update rtt.canon to always produce
>   an rtt of depth 0.
> - Pass a unit32_t type index over a HeapType to all rtt-related
>   utilities.
> - Remove infrastructure for abstract-type rtts from the wasm compilers,
>   setup-heap-internal.cc, roots.h, and module-instantiate.cc.
> - Remove ObjectReferenceKnowledge::rtt_is_i31. Remove related branches
>   from ref.test, ref.cast and br_on_cast implementations in the wasm
>   compilers.
> - Remove unused 'parent' field from WasmTypeInfo.
> - Make the parent argument optional in NewWasmTypeInfo, CreateStructMap,
>   and CreateArrayMap.
> - Use more convenient arguments in IsHeapSubtypeOf.
> - Update tests.
>
> Bug: v8:7748
> Change-Id: Ib45efe0741e6558c9b291fc8b4a75ae303146bdc
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2642248
> Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#72321}

Bug: v8:7748
Change-Id: I22b204b486fd185077cd6c7f15d492f5143f48fe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2650207
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72355}

This reverts commit b77deeca.

Reason for revert: MSVC compile fails: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win64%20-%20msvc/16535/overview

Original change's description:
> [wasm-gc] Remove abstract rtts
>
> In the latest wasm-gc spec, rtts of abstract types are no longer
> allowed. Consequently, canonical rtts of concrete types always have
> a depth of 0.
>
> Changes:
> - Change the immediate argument of rtts to a type index over a heap
>   type. Abstract it with TypeIndexImmediate in function body decoding.
>   This affects:
>   value_type.h, read_value_type(), decoding of relevant opcodes,
>   wasm subtyping, WasmInitExpr, consume_init_expr(), and
>   wasm-module-builder.cc.
> - In function-body-decoder-impl.h, update rtt.canon to always produce
>   an rtt of depth 0.
> - Pass a unit32_t type index over a HeapType to all rtt-related
>   utilities.
> - Remove infrastructure for abstract-type rtts from the wasm compilers,
>   setup-heap-internal.cc, roots.h, and module-instantiate.cc.
> - Remove ObjectReferenceKnowledge::rtt_is_i31. Remove related branches
>   from ref.test, ref.cast and br_on_cast implementations in the wasm
>   compilers.
> - Remove unused 'parent' field from WasmTypeInfo.
> - Make the parent argument optional in NewWasmTypeInfo, CreateStructMap,
>   and CreateArrayMap.
> - Use more convenient arguments in IsHeapSubtypeOf.
> - Update tests.
>
> Bug: v8:7748
> Change-Id: Ib45efe0741e6558c9b291fc8b4a75ae303146bdc
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2642248
> Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#72321}

TBR=ulan@chromium.org,jkummerow@chromium.org,manoskouk@chromium.org

Change-Id: I2f0d97f1a34f7c81c5a97d7c37925cb84c66eea3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7748
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2650206Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72322}

In the latest wasm-gc spec, rtts of abstract types are no longer
allowed. Consequently, canonical rtts of concrete types always have
a depth of 0.

Changes:
- Change the immediate argument of rtts to a type index over a heap
  type. Abstract it with TypeIndexImmediate in function body decoding.
  This affects:
  value_type.h, read_value_type(), decoding of relevant opcodes,
  wasm subtyping, WasmInitExpr, consume_init_expr(), and
  wasm-module-builder.cc.
- In function-body-decoder-impl.h, update rtt.canon to always produce
  an rtt of depth 0.
- Pass a unit32_t type index over a HeapType to all rtt-related
  utilities.
- Remove infrastructure for abstract-type rtts from the wasm compilers,
  setup-heap-internal.cc, roots.h, and module-instantiate.cc.
- Remove ObjectReferenceKnowledge::rtt_is_i31. Remove related branches
  from ref.test, ref.cast and br_on_cast implementations in the wasm
  compilers.
- Remove unused 'parent' field from WasmTypeInfo.
- Make the parent argument optional in NewWasmTypeInfo, CreateStructMap,
  and CreateArrayMap.
- Use more convenient arguments in IsHeapSubtypeOf.
- Update tests.

Bug: v8:7748
Change-Id: Ib45efe0741e6558c9b291fc8b4a75ae303146bdc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2642248
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72321}

Change-Id: I702f8c021490f0538a98cad9a61b1dbae60fb881
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2649027Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72314}

Without the adaptor frame, this is dead code.

Change-Id: Ica1ee102fcc068a58c5dcbca6122921cd1b5550a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2639760Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72185}

This reverts commit b3d09001.

Reason for revert: https://chromium-review.googlesource.com/c/v8/v8/+/2565511 has to be reverted, and this was a follow-up to that

Original change's description:
> [objects] Remove uncached internal external string type
>
> We shouldn't be creating those anymore since they are not thread-safe.
>
> Bug: v8:7790
> Change-Id: I4546d995fa32eb076c8dfe9d95301fad719c9e07
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2615347
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#72006}

TBR=rmcilroy@chromium.org,leszeks@chromium.org,solanes@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:7790
Change-Id: I4eb1a6b8446fa602eeb5bf29fbf1fe57182cdbf3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2627605Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72122}

We shouldn't be creating those anymore since they are not thread-safe.

Bug: v8:7790
Change-Id: I4546d995fa32eb076c8dfe9d95301fad719c9e07
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2615347Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72006}

Bug: v8:7748
Change-Id: I5d0cc06fafbe7fc05549a4b8fd7f602eaf838bba
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2526382
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71283}

Drive-by change: Fix wrong reference to FixedRangeBodyDescriptor in
                 implementation-visitor.cc

TBR: ulan@chromium.org
Change-Id: I8a1f468f35c38f5be1f4e8d1cfcc9f0fd2a16381
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2540546
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Auto-Submit: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71223}

This is a reland of 26f10ecd

Change compared to original CL:
The deserializer changes StrongDescriptorArray to DescriptorArray.
Since this CL uses separate BodyDescriptors for the two kinds of
descriptor arrays, this caused a DCHECK failure when the deserializer
changes the map while the object is visited from the concurrent marking
thread. Fix this by disabling the corresponding checks.


Original change's description:
> [torque] allow exported classes with custom C++ class
>
> Introduce a new annotation @customCppClass that can be used for
> non-extern @export classes, that is, generate everything, remove
> boilerplate from all the internal lists and switches, but allow
> a custom C++ class, which in turn also allows overwriting the generated
> print and verify functions.
>
> Port DescriptorArray and StrongDescriptorArray as an example.
>
> Bug: v8:7793
> Change-Id: I744e52fb4102ac49c0097f1c95bb17d301975bf0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2489687
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
> Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70989}

Bug: v8:7793
Change-Id: I7505fb111896991d16d7d113704c8c3676669f34
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2526383Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71048}

This reverts commit 26f10ecd.

Reason for revert: GC stress failures:
https://crbug.com/v8/11114

Original change's description:
> [torque] allow exported classes with custom C++ class
>
> Introduce a new annotation @customCppClass that can be used for
> non-extern @export classes, that is, generate everything, remove
> boilerplate from all the internal lists and switches, but allow
> a custom C++ class, which in turn also allows overwriting the generated
> print and verify functions.
>
> Port DescriptorArray and StrongDescriptorArray as an example.
>
> Bug: v8:7793
> Change-Id: I744e52fb4102ac49c0097f1c95bb17d301975bf0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2489687
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
> Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70989}

TBR=ulan@chromium.org,tebbi@chromium.org,seth.brenith@microsoft.com,nicohartmann@chromium.org

Change-Id: I4631db66a76f41cf62b400e8ee64df27e641a320
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7793,v8:11114
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2521911Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70994}

Introduce a new annotation @customCppClass that can be used for
non-extern @export classes, that is, generate everything, remove
boilerplate from all the internal lists and switches, but allow
a custom C++ class, which in turn also allows overwriting the generated
print and verify functions.

Port DescriptorArray and StrongDescriptorArray as an example.

Bug: v8:7793
Change-Id: I744e52fb4102ac49c0097f1c95bb17d301975bf0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2489687Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70989}

Generate DIR_METADATA files and remove metadata from OWNERS
files for v8.

R=jkummerow@chromium.org, ochang@chromium.org, yangguo@chromium.org

Bug: chromium:1113033
Change-Id: I82cbb62e438d82dbbc408e87120af39fa9da0afa
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2476680Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Auto-Submit: Edward Lesmes <ehmaldonado@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70669}

This changes OrderedHashMap, OrderedHashSet, and OrderedNameDictionary
as follows:
- Create a dedicated allocation function AllocateEmpty to create zero-
  element instances of these classes
- Fix bugs resulting from using these zero-element versions

Further, this CL
- provides a canonical empty versions of OrderedNameDictionary
- changes the types of the canonical ordered hash table and hash set
  from FixedArray to the actual subclasses

Bug: v8:7569
Change-Id: I0fe1215e7d164617afa777c8b3208a0857ab6edd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2476315
Commit-Queue: Frank Emrich <emrich@google.com>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70604}

This relands commit 3f4e9bbe.
which was a reland of c4a062a9
which was a reland of 28a30c57
which was a reland of 5d7a29c9

The change had an issue that embedders implementing heap tracing (e.g.
Unified Heap with Blink) could be passed an uninitialized pointer if
marking happened during deserialization of an object containing such a
pointer. Because of the 0xdeadbed0 uninitialized filler value, these
embedders would then receive the value 0xdeadbed0deadbed0 as the
'pointer', and crash on dereference.

There is, however, special handling already for null pointers in heap
tracing, also for dealing with not-yet initialized values. So, we can
make the uninitialized Smi filler be 0x00000000, and that will make such
embedded fields have a nullptr representation, making them follow the
normal uninitialized value bailouts.

In addition, it relands the following dependent changes, which are
relanding unchanged and are followup performance improvements.
Relanding them in the same change should allow for cleaner reverts
should they be needed.

This relands commit 76ad3ab5
[identity-map] Change resize heuristic

This relands commit 77cc96aa
[identity-map] Cache the calculated Hash

This relands commit bee5b996
[serializer] Remove Deserializer::Initialize

This relands commit c8f73f22
[serializer] Cache instance type in PostProcessNewObject

This relands commit 4e7c99ab
[identity-map] Remove double-lookups in IdentityMap

Original change's description:
> Reland^3 "[serializer] Allocate during deserialization"
>
> This is a reland of c4a062a9
> which was a reland of 28a30c57
> which was a reland of 5d7a29c9
>
> Fixes TSAN errors from non-atomic writes in the deserializer. Now all
> writes are (relaxed) atomic.
>
> Original change's description:
> > Reland^2 "[serializer] Allocate during deserialization"
> >
> > This is a reland of 28a30c57
> > which was a reland of 5d7a29c9
> >
> > The crashes were from calling RegisterDeserializerFinished on a null
> > Isolate pointer, for a deserializer that was never initialised
> > (specifically, ReadOnlyDeserializer when ROHeap is shared).
> >
> > Original change's description:
> > > Reland "[serializer] Allocate during deserialization"
> > >
> > > This is a reland of 5d7a29c9
> > >
> > > This reland shuffles around the order of checks in Heap::AllocateRawWith
> > > to not check the new space addresses until it's known that this is a new
> > > space allocation. This fixes an UBSan failure during read-only space
> > > deserialization, which happens before the new space is initialized.
> > >
> > > It also fixes some issues discovered by --stress-snapshot, around
> > > serializing ThinStrings (which are now elided as part of serialization),
> > > handle counts (I bumped the maximum handle count in that check), and
> > > clearing map transitions (the map backpointer field needed a Smi
> > > uninitialized value check).
> > >
> > > Original change's description:
> > > > [serializer] Allocate during deserialization
> > > >
> > > > This patch removes the concept of reservations and a specialized
> > > > deserializer allocator, and instead makes the deserializer allocate
> > > > directly with the Heap's Allocate method.
> > > >
> > > > The major consequence of this is that the GC can now run during
> > > > deserialization, which means that:
> > > >
> > > >   a) Deserialized objects are visible to the GC, and
> > > >   b) Objects that the deserializer/deserialized objects point to can
> > > >      move.
> > > >
> > > > Point a) is mostly not a problem due to previous work in making
> > > > deserialized objects "GC valid", i.e. making sure that they have a valid
> > > > size before any subsequent allocation/safepoint. We now additionally
> > > > have to initialize the allocated space with a valid tagged value -- this
> > > > is a magic Smi value to keep "uninitialized" checks simple.
> > > >
> > > > Point b) is solved by Handlifying the deserializer. This involves
> > > > changing any vectors of objects into vectors of Handles, and any object
> > > > keyed map into an IdentityMap (we can't use Handles as keys because
> > > > the object's address is no longer a stable hash).
> > > >
> > > > Back-references can no longer be direct chunk offsets, so instead the
> > > > deserializer stores a Handle to each deserialized object, and the
> > > > backreference is an index into this handle array. This encoding could
> > > > be optimized in the future with e.g. a second pass over the serialized
> > > > array which emits a different bytecode for objects that are and aren't
> > > > back-referenced.
> > > >
> > > > Additionally, the slot-walk over objects to initialize them can no
> > > > longer use absolute slot offsets, as again an object may move and its
> > > > slot address would become invalid. Now, slots are walked as relative
> > > > offsets to a Handle to the object, or as absolute slots for the case of
> > > > root pointers. A concept of "slot accessor" is introduced to share the
> > > > code between these two modes, and writing the slot (including write
> > > > barriers) is abstracted into this accessor.
> > > >
> > > > Finally, the Code body walk is modified to deserialize all objects
> > > > referred to by RelocInfos before doing the RelocInfo walk itself. This
> > > > is because RelocInfoIterator uses raw pointers, so we cannot allocate
> > > > during a RelocInfo walk.
> > > >
> > > > As a drive-by, the VariableRawData bytecode is tweaked to use tagged
> > > > size rather than byte size -- the size is expected to be tagged-aligned
> > > > anyway, so now we get an extra few bits in the size encoding.
> > > >
> > > > Bug: chromium:1075999
> > > > Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
> > > > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
> > > > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > > > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > > > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > > > Cr-Commit-Position: refs/heads/master@{#70229}

Bug: chromium:1075999
Change-Id: Ib514a4ef16bd02bfb60d046ecbf8fae1ead64a98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2452689
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70366}

This reverts commit 3f4e9bbe, along
with the following dependent changes (reverted to make this a clean revert):
76ad3ab5 [identity-map] Change resize heuristic
77cc96aa [identity-map] Cache the calculated Hash
bee5b996 [serializer] Remove Deserializer::Initialize
c8f73f22 [serializer] Cache instance type in PostProcessNewObject
4e7c99ab [identity-map] Remove double-lookups in IdentityMap

Reason for revert: major crash spike on Canary (https://crbug.com/1135027)

Original change's description:
> Reland^3 "[serializer] Allocate during deserialization"
>
> This is a reland of c4a062a9
> which was a reland of 28a30c57
> which was a reland of 5d7a29c9
>
> Fixes TSAN errors from non-atomic writes in the deserializer. Now all
> writes are (relaxed) atomic.
>
> Original change's description:
> > Reland^2 "[serializer] Allocate during deserialization"
> >
> > This is a reland of 28a30c57
> > which was a reland of 5d7a29c9
> >
> > The crashes were from calling RegisterDeserializerFinished on a null
> > Isolate pointer, for a deserializer that was never initialised
> > (specifically, ReadOnlyDeserializer when ROHeap is shared).
> >
> > Original change's description:
> > > Reland "[serializer] Allocate during deserialization"
> > >
> > > This is a reland of 5d7a29c9
> > >
> > > This reland shuffles around the order of checks in Heap::AllocateRawWith
> > > to not check the new space addresses until it's known that this is a new
> > > space allocation. This fixes an UBSan failure during read-only space
> > > deserialization, which happens before the new space is initialized.
> > >
> > > It also fixes some issues discovered by --stress-snapshot, around
> > > serializing ThinStrings (which are now elided as part of serialization),
> > > handle counts (I bumped the maximum handle count in that check), and
> > > clearing map transitions (the map backpointer field needed a Smi
> > > uninitialized value check).
> > >
> > > Original change's description:
> > > > [serializer] Allocate during deserialization
> > > >
> > > > This patch removes the concept of reservations and a specialized
> > > > deserializer allocator, and instead makes the deserializer allocate
> > > > directly with the Heap's Allocate method.
> > > >
> > > > The major consequence of this is that the GC can now run during
> > > > deserialization, which means that:
> > > >
> > > >   a) Deserialized objects are visible to the GC, and
> > > >   b) Objects that the deserializer/deserialized objects point to can
> > > >      move.
> > > >
> > > > Point a) is mostly not a problem due to previous work in making
> > > > deserialized objects "GC valid", i.e. making sure that they have a valid
> > > > size before any subsequent allocation/safepoint. We now additionally
> > > > have to initialize the allocated space with a valid tagged value -- this
> > > > is a magic Smi value to keep "uninitialized" checks simple.
> > > >
> > > > Point b) is solved by Handlifying the deserializer. This involves
> > > > changing any vectors of objects into vectors of Handles, and any object
> > > > keyed map into an IdentityMap (we can't use Handles as keys because
> > > > the object's address is no longer a stable hash).
> > > >
> > > > Back-references can no longer be direct chunk offsets, so instead the
> > > > deserializer stores a Handle to each deserialized object, and the
> > > > backreference is an index into this handle array. This encoding could
> > > > be optimized in the future with e.g. a second pass over the serialized
> > > > array which emits a different bytecode for objects that are and aren't
> > > > back-referenced.
> > > >
> > > > Additionally, the slot-walk over objects to initialize them can no
> > > > longer use absolute slot offsets, as again an object may move and its
> > > > slot address would become invalid. Now, slots are walked as relative
> > > > offsets to a Handle to the object, or as absolute slots for the case of
> > > > root pointers. A concept of "slot accessor" is introduced to share the
> > > > code between these two modes, and writing the slot (including write
> > > > barriers) is abstracted into this accessor.
> > > >
> > > > Finally, the Code body walk is modified to deserialize all objects
> > > > referred to by RelocInfos before doing the RelocInfo walk itself. This
> > > > is because RelocInfoIterator uses raw pointers, so we cannot allocate
> > > > during a RelocInfo walk.
> > > >
> > > > As a drive-by, the VariableRawData bytecode is tweaked to use tagged
> > > > size rather than byte size -- the size is expected to be tagged-aligned
> > > > anyway, so now we get an extra few bits in the size encoding.
> > > >
> > > > Bug: chromium:1075999
> > > > Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
> > > > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
> > > > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > > > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > > > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > > > Cr-Commit-Position: refs/heads/master@{#70229}
> > >
> > > Bug: chromium:1075999
> > > Change-Id: Ibc77cc48b3440b4a28b09746cfc47e50c340ce54
> > > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440828
> > > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > > Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> > > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#70267}
> >
> > Tbr: jgruber@chromium.org,ulan@chromium.org
> > Bug: chromium:1075999
> > Change-Id: Iaa8dc54895866ada0e34a7c9e8fff9ae1cb13f2d
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2444991
> > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#70279}
>
> Tbr: jgruber@chromium.org,ulan@chromium.org
> Cq-Include-Trybots: luci.v8.try:v8_linux64_tsan_rel_ng,v8_linux64_tsan_no_cm_rel_ng,v8_linux64_tsan_isolates_rel_ng
> Bug: chromium:1075999
> Change-Id: I0b9b11644aebc4cc8b07c62a0f765b24e4d73d89
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2445872
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70288}

TBR=ulan@chromium.org,jgruber@chromium.org,leszeks@chromium.org,dinfuehr@chromium.org

Bug: chromium:1075999, chromium:1135027
Change-Id: I5d0d9e49c0302d94ff7291834f5f18e7a0839eb7
Cq-Include-Trybots: luci.v8.try:v8_linux64_tsan_rel_ng,v8_linux64_tsan_no_cm_rel_ng,v8_linux64_tsan_isolates_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2451030Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70328}

This is a reland of c4a062a9
which was a reland of 28a30c57
which was a reland of 5d7a29c9

Fixes TSAN errors from non-atomic writes in the deserializer. Now all
writes are (relaxed) atomic.

Original change's description:
> Reland^2 "[serializer] Allocate during deserialization"
>
> This is a reland of 28a30c57
> which was a reland of 5d7a29c9
>
> The crashes were from calling RegisterDeserializerFinished on a null
> Isolate pointer, for a deserializer that was never initialised
> (specifically, ReadOnlyDeserializer when ROHeap is shared).
>
> Original change's description:
> > Reland "[serializer] Allocate during deserialization"
> >
> > This is a reland of 5d7a29c9
> >
> > This reland shuffles around the order of checks in Heap::AllocateRawWith
> > to not check the new space addresses until it's known that this is a new
> > space allocation. This fixes an UBSan failure during read-only space
> > deserialization, which happens before the new space is initialized.
> >
> > It also fixes some issues discovered by --stress-snapshot, around
> > serializing ThinStrings (which are now elided as part of serialization),
> > handle counts (I bumped the maximum handle count in that check), and
> > clearing map transitions (the map backpointer field needed a Smi
> > uninitialized value check).
> >
> > Original change's description:
> > > [serializer] Allocate during deserialization
> > >
> > > This patch removes the concept of reservations and a specialized
> > > deserializer allocator, and instead makes the deserializer allocate
> > > directly with the Heap's Allocate method.
> > >
> > > The major consequence of this is that the GC can now run during
> > > deserialization, which means that:
> > >
> > >   a) Deserialized objects are visible to the GC, and
> > >   b) Objects that the deserializer/deserialized objects point to can
> > >      move.
> > >
> > > Point a) is mostly not a problem due to previous work in making
> > > deserialized objects "GC valid", i.e. making sure that they have a valid
> > > size before any subsequent allocation/safepoint. We now additionally
> > > have to initialize the allocated space with a valid tagged value -- this
> > > is a magic Smi value to keep "uninitialized" checks simple.
> > >
> > > Point b) is solved by Handlifying the deserializer. This involves
> > > changing any vectors of objects into vectors of Handles, and any object
> > > keyed map into an IdentityMap (we can't use Handles as keys because
> > > the object's address is no longer a stable hash).
> > >
> > > Back-references can no longer be direct chunk offsets, so instead the
> > > deserializer stores a Handle to each deserialized object, and the
> > > backreference is an index into this handle array. This encoding could
> > > be optimized in the future with e.g. a second pass over the serialized
> > > array which emits a different bytecode for objects that are and aren't
> > > back-referenced.
> > >
> > > Additionally, the slot-walk over objects to initialize them can no
> > > longer use absolute slot offsets, as again an object may move and its
> > > slot address would become invalid. Now, slots are walked as relative
> > > offsets to a Handle to the object, or as absolute slots for the case of
> > > root pointers. A concept of "slot accessor" is introduced to share the
> > > code between these two modes, and writing the slot (including write
> > > barriers) is abstracted into this accessor.
> > >
> > > Finally, the Code body walk is modified to deserialize all objects
> > > referred to by RelocInfos before doing the RelocInfo walk itself. This
> > > is because RelocInfoIterator uses raw pointers, so we cannot allocate
> > > during a RelocInfo walk.
> > >
> > > As a drive-by, the VariableRawData bytecode is tweaked to use tagged
> > > size rather than byte size -- the size is expected to be tagged-aligned
> > > anyway, so now we get an extra few bits in the size encoding.
> > >
> > > Bug: chromium:1075999
> > > Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
> > > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
> > > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#70229}
> >
> > Bug: chromium:1075999
> > Change-Id: Ibc77cc48b3440b4a28b09746cfc47e50c340ce54
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440828
> > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#70267}
>
> Tbr: jgruber@chromium.org,ulan@chromium.org
> Bug: chromium:1075999
> Change-Id: Iaa8dc54895866ada0e34a7c9e8fff9ae1cb13f2d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2444991
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70279}

Tbr: jgruber@chromium.org,ulan@chromium.org
Cq-Include-Trybots: luci.v8.try:v8_linux64_tsan_rel_ng,v8_linux64_tsan_no_cm_rel_ng,v8_linux64_tsan_isolates_rel_ng
Bug: chromium:1075999
Change-Id: I0b9b11644aebc4cc8b07c62a0f765b24e4d73d89
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2445872
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70288}

This reverts commit c4a062a9.

Reason for revert: TSan issues: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20TSAN/33504

Original change's description:
> Reland^2 "[serializer] Allocate during deserialization"
>
> This is a reland of 28a30c57
> which was a reland of 5d7a29c9
>
> The crashes were from calling RegisterDeserializerFinished on a null
> Isolate pointer, for a deserializer that was never initialised
> (specifically, ReadOnlyDeserializer when ROHeap is shared).
>
> Original change's description:
> > Reland "[serializer] Allocate during deserialization"
> >
> > This is a reland of 5d7a29c9
> >
> > This reland shuffles around the order of checks in Heap::AllocateRawWith
> > to not check the new space addresses until it's known that this is a new
> > space allocation. This fixes an UBSan failure during read-only space
> > deserialization, which happens before the new space is initialized.
> >
> > It also fixes some issues discovered by --stress-snapshot, around
> > serializing ThinStrings (which are now elided as part of serialization),
> > handle counts (I bumped the maximum handle count in that check), and
> > clearing map transitions (the map backpointer field needed a Smi
> > uninitialized value check).
> >
> > Original change's description:
> > > [serializer] Allocate during deserialization
> > >
> > > This patch removes the concept of reservations and a specialized
> > > deserializer allocator, and instead makes the deserializer allocate
> > > directly with the Heap's Allocate method.
> > >
> > > The major consequence of this is that the GC can now run during
> > > deserialization, which means that:
> > >
> > >   a) Deserialized objects are visible to the GC, and
> > >   b) Objects that the deserializer/deserialized objects point to can
> > >      move.
> > >
> > > Point a) is mostly not a problem due to previous work in making
> > > deserialized objects "GC valid", i.e. making sure that they have a valid
> > > size before any subsequent allocation/safepoint. We now additionally
> > > have to initialize the allocated space with a valid tagged value -- this
> > > is a magic Smi value to keep "uninitialized" checks simple.
> > >
> > > Point b) is solved by Handlifying the deserializer. This involves
> > > changing any vectors of objects into vectors of Handles, and any object
> > > keyed map into an IdentityMap (we can't use Handles as keys because
> > > the object's address is no longer a stable hash).
> > >
> > > Back-references can no longer be direct chunk offsets, so instead the
> > > deserializer stores a Handle to each deserialized object, and the
> > > backreference is an index into this handle array. This encoding could
> > > be optimized in the future with e.g. a second pass over the serialized
> > > array which emits a different bytecode for objects that are and aren't
> > > back-referenced.
> > >
> > > Additionally, the slot-walk over objects to initialize them can no
> > > longer use absolute slot offsets, as again an object may move and its
> > > slot address would become invalid. Now, slots are walked as relative
> > > offsets to a Handle to the object, or as absolute slots for the case of
> > > root pointers. A concept of "slot accessor" is introduced to share the
> > > code between these two modes, and writing the slot (including write
> > > barriers) is abstracted into this accessor.
> > >
> > > Finally, the Code body walk is modified to deserialize all objects
> > > referred to by RelocInfos before doing the RelocInfo walk itself. This
> > > is because RelocInfoIterator uses raw pointers, so we cannot allocate
> > > during a RelocInfo walk.
> > >
> > > As a drive-by, the VariableRawData bytecode is tweaked to use tagged
> > > size rather than byte size -- the size is expected to be tagged-aligned
> > > anyway, so now we get an extra few bits in the size encoding.
> > >
> > > Bug: chromium:1075999
> > > Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
> > > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
> > > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#70229}
> >
> > Bug: chromium:1075999
> > Change-Id: Ibc77cc48b3440b4a28b09746cfc47e50c340ce54
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440828
> > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#70267}
>
> Tbr: jgruber@chromium.org,ulan@chromium.org
> Bug: chromium:1075999
> Change-Id: Iaa8dc54895866ada0e34a7c9e8fff9ae1cb13f2d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2444991
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70279}

TBR=ulan@chromium.org,jgruber@chromium.org,leszeks@chromium.org

Change-Id: Ib2f01db4cd9b55639d6a4af971bda865edb45e84
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1075999
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2445250Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70280}

This is a reland of 28a30c57
which was a reland of 5d7a29c9

The crashes were from calling RegisterDeserializerFinished on a null
Isolate pointer, for a deserializer that was never initialised
(specifically, ReadOnlyDeserializer when ROHeap is shared).

Original change's description:
> Reland "[serializer] Allocate during deserialization"
>
> This is a reland of 5d7a29c9
>
> This reland shuffles around the order of checks in Heap::AllocateRawWith
> to not check the new space addresses until it's known that this is a new
> space allocation. This fixes an UBSan failure during read-only space
> deserialization, which happens before the new space is initialized.
>
> It also fixes some issues discovered by --stress-snapshot, around
> serializing ThinStrings (which are now elided as part of serialization),
> handle counts (I bumped the maximum handle count in that check), and
> clearing map transitions (the map backpointer field needed a Smi
> uninitialized value check).
>
> Original change's description:
> > [serializer] Allocate during deserialization
> >
> > This patch removes the concept of reservations and a specialized
> > deserializer allocator, and instead makes the deserializer allocate
> > directly with the Heap's Allocate method.
> >
> > The major consequence of this is that the GC can now run during
> > deserialization, which means that:
> >
> >   a) Deserialized objects are visible to the GC, and
> >   b) Objects that the deserializer/deserialized objects point to can
> >      move.
> >
> > Point a) is mostly not a problem due to previous work in making
> > deserialized objects "GC valid", i.e. making sure that they have a valid
> > size before any subsequent allocation/safepoint. We now additionally
> > have to initialize the allocated space with a valid tagged value -- this
> > is a magic Smi value to keep "uninitialized" checks simple.
> >
> > Point b) is solved by Handlifying the deserializer. This involves
> > changing any vectors of objects into vectors of Handles, and any object
> > keyed map into an IdentityMap (we can't use Handles as keys because
> > the object's address is no longer a stable hash).
> >
> > Back-references can no longer be direct chunk offsets, so instead the
> > deserializer stores a Handle to each deserialized object, and the
> > backreference is an index into this handle array. This encoding could
> > be optimized in the future with e.g. a second pass over the serialized
> > array which emits a different bytecode for objects that are and aren't
> > back-referenced.
> >
> > Additionally, the slot-walk over objects to initialize them can no
> > longer use absolute slot offsets, as again an object may move and its
> > slot address would become invalid. Now, slots are walked as relative
> > offsets to a Handle to the object, or as absolute slots for the case of
> > root pointers. A concept of "slot accessor" is introduced to share the
> > code between these two modes, and writing the slot (including write
> > barriers) is abstracted into this accessor.
> >
> > Finally, the Code body walk is modified to deserialize all objects
> > referred to by RelocInfos before doing the RelocInfo walk itself. This
> > is because RelocInfoIterator uses raw pointers, so we cannot allocate
> > during a RelocInfo walk.
> >
> > As a drive-by, the VariableRawData bytecode is tweaked to use tagged
> > size rather than byte size -- the size is expected to be tagged-aligned
> > anyway, so now we get an extra few bits in the size encoding.
> >
> > Bug: chromium:1075999
> > Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
> > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#70229}
>
> Bug: chromium:1075999
> Change-Id: Ibc77cc48b3440b4a28b09746cfc47e50c340ce54
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440828
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70267}

Tbr: jgruber@chromium.org,ulan@chromium.org
Bug: chromium:1075999
Change-Id: Iaa8dc54895866ada0e34a7c9e8fff9ae1cb13f2d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2444991Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70279}

This reverts commit 28a30c57.

Reason for revert: Broke Test262 https://ci.chromium.org/p/v8/builders/ci/V8%20Linux%20-%20shared/38638?

Original change's description:
> Reland "[serializer] Allocate during deserialization"
>
> This is a reland of 5d7a29c9
>
> This reland shuffles around the order of checks in Heap::AllocateRawWith
> to not check the new space addresses until it's known that this is a new
> space allocation. This fixes an UBSan failure during read-only space
> deserialization, which happens before the new space is initialized.
>
> It also fixes some issues discovered by --stress-snapshot, around
> serializing ThinStrings (which are now elided as part of serialization),
> handle counts (I bumped the maximum handle count in that check), and
> clearing map transitions (the map backpointer field needed a Smi
> uninitialized value check).
>
> Original change's description:
> > [serializer] Allocate during deserialization
> >
> > This patch removes the concept of reservations and a specialized
> > deserializer allocator, and instead makes the deserializer allocate
> > directly with the Heap's Allocate method.
> >
> > The major consequence of this is that the GC can now run during
> > deserialization, which means that:
> >
> >   a) Deserialized objects are visible to the GC, and
> >   b) Objects that the deserializer/deserialized objects point to can
> >      move.
> >
> > Point a) is mostly not a problem due to previous work in making
> > deserialized objects "GC valid", i.e. making sure that they have a valid
> > size before any subsequent allocation/safepoint. We now additionally
> > have to initialize the allocated space with a valid tagged value -- this
> > is a magic Smi value to keep "uninitialized" checks simple.
> >
> > Point b) is solved by Handlifying the deserializer. This involves
> > changing any vectors of objects into vectors of Handles, and any object
> > keyed map into an IdentityMap (we can't use Handles as keys because
> > the object's address is no longer a stable hash).
> >
> > Back-references can no longer be direct chunk offsets, so instead the
> > deserializer stores a Handle to each deserialized object, and the
> > backreference is an index into this handle array. This encoding could
> > be optimized in the future with e.g. a second pass over the serialized
> > array which emits a different bytecode for objects that are and aren't
> > back-referenced.
> >
> > Additionally, the slot-walk over objects to initialize them can no
> > longer use absolute slot offsets, as again an object may move and its
> > slot address would become invalid. Now, slots are walked as relative
> > offsets to a Handle to the object, or as absolute slots for the case of
> > root pointers. A concept of "slot accessor" is introduced to share the
> > code between these two modes, and writing the slot (including write
> > barriers) is abstracted into this accessor.
> >
> > Finally, the Code body walk is modified to deserialize all objects
> > referred to by RelocInfos before doing the RelocInfo walk itself. This
> > is because RelocInfoIterator uses raw pointers, so we cannot allocate
> > during a RelocInfo walk.
> >
> > As a drive-by, the VariableRawData bytecode is tweaked to use tagged
> > size rather than byte size -- the size is expected to be tagged-aligned
> > anyway, so now we get an extra few bits in the size encoding.
> >
> > Bug: chromium:1075999
> > Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
> > Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#70229}
>
> Bug: chromium:1075999
> Change-Id: Ibc77cc48b3440b4a28b09746cfc47e50c340ce54
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440828
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Auto-Submit: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70267}

TBR=ulan@chromium.org,jgruber@chromium.org,leszeks@chromium.org

Change-Id: Ieed68332ef6a7ad36db061e3f48be0f28673d7a2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1075999
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2441608Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70268}

This is a reland of 5d7a29c9

This reland shuffles around the order of checks in Heap::AllocateRawWith
to not check the new space addresses until it's known that this is a new
space allocation. This fixes an UBSan failure during read-only space
deserialization, which happens before the new space is initialized.

It also fixes some issues discovered by --stress-snapshot, around
serializing ThinStrings (which are now elided as part of serialization),
handle counts (I bumped the maximum handle count in that check), and
clearing map transitions (the map backpointer field needed a Smi
uninitialized value check).

Original change's description:
> [serializer] Allocate during deserialization
>
> This patch removes the concept of reservations and a specialized
> deserializer allocator, and instead makes the deserializer allocate
> directly with the Heap's Allocate method.
>
> The major consequence of this is that the GC can now run during
> deserialization, which means that:
>
>   a) Deserialized objects are visible to the GC, and
>   b) Objects that the deserializer/deserialized objects point to can
>      move.
>
> Point a) is mostly not a problem due to previous work in making
> deserialized objects "GC valid", i.e. making sure that they have a valid
> size before any subsequent allocation/safepoint. We now additionally
> have to initialize the allocated space with a valid tagged value -- this
> is a magic Smi value to keep "uninitialized" checks simple.
>
> Point b) is solved by Handlifying the deserializer. This involves
> changing any vectors of objects into vectors of Handles, and any object
> keyed map into an IdentityMap (we can't use Handles as keys because
> the object's address is no longer a stable hash).
>
> Back-references can no longer be direct chunk offsets, so instead the
> deserializer stores a Handle to each deserialized object, and the
> backreference is an index into this handle array. This encoding could
> be optimized in the future with e.g. a second pass over the serialized
> array which emits a different bytecode for objects that are and aren't
> back-referenced.
>
> Additionally, the slot-walk over objects to initialize them can no
> longer use absolute slot offsets, as again an object may move and its
> slot address would become invalid. Now, slots are walked as relative
> offsets to a Handle to the object, or as absolute slots for the case of
> root pointers. A concept of "slot accessor" is introduced to share the
> code between these two modes, and writing the slot (including write
> barriers) is abstracted into this accessor.
>
> Finally, the Code body walk is modified to deserialize all objects
> referred to by RelocInfos before doing the RelocInfo walk itself. This
> is because RelocInfoIterator uses raw pointers, so we cannot allocate
> during a RelocInfo walk.
>
> As a drive-by, the VariableRawData bytecode is tweaked to use tagged
> size rather than byte size -- the size is expected to be tagged-aligned
> anyway, so now we get an extra few bits in the size encoding.
>
> Bug: chromium:1075999
> Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70229}

Bug: chromium:1075999
Change-Id: Ibc77cc48b3440b4a28b09746cfc47e50c340ce54
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440828
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70267}

This reverts commit 5d7a29c9.

Reason for revert: UBSan -- https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20UBSan/13100

Original change's description:
> [serializer] Allocate during deserialization
>
> This patch removes the concept of reservations and a specialized
> deserializer allocator, and instead makes the deserializer allocate
> directly with the Heap's Allocate method.
>
> The major consequence of this is that the GC can now run during
> deserialization, which means that:
>
>   a) Deserialized objects are visible to the GC, and
>   b) Objects that the deserializer/deserialized objects point to can
>      move.
>
> Point a) is mostly not a problem due to previous work in making
> deserialized objects "GC valid", i.e. making sure that they have a valid
> size before any subsequent allocation/safepoint. We now additionally
> have to initialize the allocated space with a valid tagged value -- this
> is a magic Smi value to keep "uninitialized" checks simple.
>
> Point b) is solved by Handlifying the deserializer. This involves
> changing any vectors of objects into vectors of Handles, and any object
> keyed map into an IdentityMap (we can't use Handles as keys because
> the object's address is no longer a stable hash).
>
> Back-references can no longer be direct chunk offsets, so instead the
> deserializer stores a Handle to each deserialized object, and the
> backreference is an index into this handle array. This encoding could
> be optimized in the future with e.g. a second pass over the serialized
> array which emits a different bytecode for objects that are and aren't
> back-referenced.
>
> Additionally, the slot-walk over objects to initialize them can no
> longer use absolute slot offsets, as again an object may move and its
> slot address would become invalid. Now, slots are walked as relative
> offsets to a Handle to the object, or as absolute slots for the case of
> root pointers. A concept of "slot accessor" is introduced to share the
> code between these two modes, and writing the slot (including write
> barriers) is abstracted into this accessor.
>
> Finally, the Code body walk is modified to deserialize all objects
> referred to by RelocInfos before doing the RelocInfo walk itself. This
> is because RelocInfoIterator uses raw pointers, so we cannot allocate
> during a RelocInfo walk.
>
> As a drive-by, the VariableRawData bytecode is tweaked to use tagged
> size rather than byte size -- the size is expected to be tagged-aligned
> anyway, so now we get an extra few bits in the size encoding.
>
> Bug: chromium:1075999
> Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70229}

TBR=ulan@chromium.org,jgruber@chromium.org,leszeks@chromium.org

Change-Id: I2bd792a24861e8f54897e51522769b50f8f814e2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1075999
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440827
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70231}

This patch removes the concept of reservations and a specialized
deserializer allocator, and instead makes the deserializer allocate
directly with the Heap's Allocate method.

The major consequence of this is that the GC can now run during
deserialization, which means that:

  a) Deserialized objects are visible to the GC, and
  b) Objects that the deserializer/deserialized objects point to can
     move.

Point a) is mostly not a problem due to previous work in making
deserialized objects "GC valid", i.e. making sure that they have a valid
size before any subsequent allocation/safepoint. We now additionally
have to initialize the allocated space with a valid tagged value -- this
is a magic Smi value to keep "uninitialized" checks simple.

Point b) is solved by Handlifying the deserializer. This involves
changing any vectors of objects into vectors of Handles, and any object
keyed map into an IdentityMap (we can't use Handles as keys because
the object's address is no longer a stable hash).

Back-references can no longer be direct chunk offsets, so instead the
deserializer stores a Handle to each deserialized object, and the
backreference is an index into this handle array. This encoding could
be optimized in the future with e.g. a second pass over the serialized
array which emits a different bytecode for objects that are and aren't
back-referenced.

Additionally, the slot-walk over objects to initialize them can no
longer use absolute slot offsets, as again an object may move and its
slot address would become invalid. Now, slots are walked as relative
offsets to a Handle to the object, or as absolute slots for the case of
root pointers. A concept of "slot accessor" is introduced to share the
code between these two modes, and writing the slot (including write
barriers) is abstracted into this accessor.

Finally, the Code body walk is modified to deserialize all objects
referred to by RelocInfos before doing the RelocInfo walk itself. This
is because RelocInfoIterator uses raw pointers, so we cannot allocate
during a RelocInfo walk.

As a drive-by, the VariableRawData bytecode is tweaked to use tagged
size rather than byte size -- the size is expected to be tagged-aligned
anyway, so now we get an extra few bits in the size encoding.

Bug: chromium:1075999
Change-Id: I672c42f553f2669888cc5e35d692c1b8ece1845e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2404451
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70229}