This is a reland of commit e2066ff6

Changes since revert:
- Rebased against c9918524, which
  uses the external pointer table for the WaiterQueueNode stored
  in the state field when compressing pointers. This relaxes
  the alignment requirement of the state field to be 4-bytes when
  compressing pointers.
- Moved the state field into the JSSynchronizationPrimitive base
  class, since alignment and padding can now be made simpler.

Original change's description:
> [shared-struct] Add Atomics.Condition
>
> Bug: v8:12547
> Change-Id: Id439aef9cab3348171a23378cdd47ede5f4d7288
> Cq-Include-Trybots: luci.v8.try:v8_linux_arm64_rel_ng,v8_linux64_tsan_rel_ng
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3630350
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Reviewed-by: Adam Klein <adamk@chromium.org>
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#81734}

Bug: v8:12547
Change-Id: I638304c3d5722c64bd04708ed4cf84863cdebb81
Cq-Include-Trybots: luci.v8.try:v8_linux_arm64_rel_ng,v8_linux64_tsan_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3763787Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82278}

Use a single SBFX instruction for Word64Sar(ChangeInt32ToInt64(x), imm)
when possible.

Using PGO, this improves Speedometer2 by 0.4% on a Cortex-A55 machine,
and 0.27% on a Neoverse-N1 machine.

Change-Id: I6fea5e473f0f0869f8f6cebd9a4e61bb2fc6e9ef
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3807586Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Rodolph Perfetta <rodolph.perfetta@arm.com>
Reviewed-by: Jakob Linke <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82277}

noextern is the abstract null type for the extern type.

Bug: v8:7748
Change-Id: I03ac0daf3051f479e096f3d05f4fa7cbf03968f1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3810191Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Matthias Liedtke <mliedtke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82276}

We now have different mechanisms for black allocation, for regular
sized objects we will set all mark bits for the LAB. For large
objects we will set the mark bit when initializing that large page.

So when we reach this method, the object is already marked black.

Bug: v8:11708
Change-Id: Ie0f82f78eefe06a25103264098cc59a3ee46d20c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3817742
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82275}

nofunc is the abstract null type, the equivalent of none but for the
function type hierarchy.
none and nofunc (and later on noextern) all can only represent a null
value, however their nulls are distinct (as there isn't any subtype
relationship between them).

Bug: v8:7748
Change-Id: Ic5ae502cc21a581ca2e0f5abc46139435d950af9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3805884Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Matthias Liedtke <mliedtke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82274}

This might or might not give clang-tidy a hint that the reported case
(see issue) cannot happen. It might also generate slightly better code
by giving hints to the compiler.
Note that V8_ASSUME is actually a DCHECK in DEBUG builds, so we do not
loose any checks here.

Some DCHECKs were removed because they are redundant
(RegisterBase::code() assumes to be only called on valid registers).

R=jkummerow@chromium.org

Bug: chromium:1349619
Change-Id: I467e7917a87ec86dd692f0edeed6bb72e0393cc4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3804667
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82273}

We should verify the consistency of the objects we produced after deserializing successfully.

Bug: v8:11525
Change-Id: Ieec1aa7112ab6eda0c61a1a9ab78e86ad8352942
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3813061
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82272}

The test-gc cctest loads the WasmCode from the NativeModule and then
executes it. With lazy compilation, the WasmCode object first has to get
generated before it can get loaded.

R=jkummerow@chromium.org

Bug: v8:12852
Change-Id: I83a8a2433ac5d11690c82f07e4ae01ddc979821c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3809811
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82271}

Keep page flags which are used in the write barrier together in order
to help reduce code size and reduce register usage.

Bug: v8:11708
Change-Id: I42efa1eeb431dea338d65aef0318cba479f2f431
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811158Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82270}

Bug: v8:7700
Change-Id: Ib27a3a818189acb5c1a1f39543762b3f0fcd9d69
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3815485Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Cr-Commit-Position: refs/heads/main@{#82269}

...in Runtime_StringToArray.

When a string is sliced from an externalized two-byte string that has
only one-byte chars, String::IsFlat() and
should not call ToOneByteVector() on it and instead we should use

String: :IsOneByteRepresentation() can both be true, while
FlatContent: :IsOneByte() returns false. In this case we
String: :Get() to get the individual characters.
Bug: chromium:1350270
Change-Id: I735408602072279f09b32e1997c97b2900942bdd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3813070Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Cr-Commit-Position: refs/heads/main@{#82268}

This change removes the subtyping between funcref and anyref.
Currently, nullref (ref null none) is still a subtype of funcref and externref.
This has to be adapted in a follow-up change introducing nullexternref
(ref null noextern) and nullfuncref (ref null nofunc).

Bug: v8:7748
Change-Id: I77a1b3fef387faf710f7bf7bf9d4655fb600ffdc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3804253Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Matthias Liedtke <mliedtke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82267}

Add a --deopt-to-baseline flag, on by default, which allows returning to
sparkplug code when deoptimizing.

However when we turn this off, no longer deoptimizing to baseline code
means we can omit marking most bytecodes as valid jump targets. Leaving
just OSR and exception handling entry points.

This reduces the baseline code size by ~18% on Arm64.

Bug: v8:13082
Change-Id: I5b5a6679465807d7fe812cb977464167efffa7ab
Cq-Include-Trybots: luci.v8.try:v8_linux_arm64_cfi_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3785006Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/main@{#82266}

In https://crrev.com/c/3811502 metrics for lazy compilation were
introduced that get recorded 5 seconds and 20 seconds after
instantiation. With this CL we record these metrics also 60 seconds and
120 seconds after instantiation.

R=clemensb@chromium.org

Bug: v8:12852
Change-Id: If95a3453f6a8510b567d291158d4119b022c1c9b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3810248
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82265}

This reverts commit 5965c90b.

Reason for revert: breaks tree

Original change's description:
> Move some string allocation functions from Factory to FactoryBase
>
> In a subsequent CL, I'll need to do String allocations in Turbofan (in
> the background), where only a LocalFactory is available. By moving
> those string allocation functions to FactoryBase, they will also be
> available in the LocalFactory.
>
> Change-Id: I066bbd4b5016645de183633ef237986e0ae50f5d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811581
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Darius Mercadier <dmercadier@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#82262}

Change-Id: I27b4dd06286562ec67e5e6e681e6bcebbff08980
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3816662
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Owners-Override: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82264}

... - a code range size agnostic version of InterpreterEntryTrampoline
builtin. The new builtin is fully compatible with the default version
and used as a template for creating interpreter entry trampoline
Code objects when --interpreted-frames-native-stack is enabled.

This CL introduces a new assembler option "position_independent_code"
which affects the way builtin calls are generated.
This mode is enabled only for InterpreterEntryTrampolineForProfiling.

Motivation:

* InterpreterEntryTrampoline uses RelocInfo::CODE_TARGET for calling
  other builtins which requires the code range to be small enough to
  allow PC-relative jumps/calls between Code objects. This is the
  reason why --interpreted-frames-native-stack was not supported on
  arm and might not work on arm64 because the code range is bigger
  than the max PC-relative distance for call/jump instructions.
  The new builtin calls other builtins via builtins entry table which
  makes the code fully relocatable and usable for any code range size.

* RelocInfo::CODE_TARGET requires a target code to be materialized
  as a Code object which contradicts the Code-less builtins goal.

* The --interpreted-frames-native-stack is rarely used in the wild but
  we have to pay the price of deserializing InterpreterEntryTrampoline
  builtin as a Code object which consumes address space in the code
  range and thus limits the number of V8 isolates that can be created
  because of code range exhaustion. Now the pointer compression cage
  becomes the limiting factor instead of the code range.

* We can remove complicated logic of Factory::CopyCode() and respective
  support on GC side.

Bug: v8:11880, v8:8713, v8:12592
Change-Id: Ib72e28c03496c43db42f6fe46622def12e102f31
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811287Reviewed-by: Jakob Linke <jgruber@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82263}

In a subsequent CL, I'll need to do String allocations in Turbofan (in
the background), where only a LocalFactory is available. By moving
those string allocation functions to FactoryBase, they will also be
available in the LocalFactory.

Change-Id: I066bbd4b5016645de183633ef237986e0ae50f5d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811581Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Darius Mercadier <dmercadier@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82262}

So far there was no support for allocating large objects in the
shared heap.

Bug: v8:11708
Change-Id: Ie4ec8244fee2e75fc0e2265847fe5976da2645ea
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811579Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82261}

All the known issues (GPU bot failures) have been fixed.

Original change's description:
> cppgc: Enable pointer compression by default on Desktop
>
> The CL enables pointer compression in Oilpan.
>
> For sherrifs: the CL may cause some slight perf regressions (likely
> blink_perf.*), due to slightly higher cost of compression and
> decomrpession.
>
> Speedometer2 is not expected to regress, as was checked locally. Such a
> slight performance degradation is compensated by memory savings that are
> expected to be around 10-20% of Oilpan committed size (~2.5-5% of Renderer
> PMF).

Bug: chromium:1325007
Change-Id: I52572ba30459dcdfd6219cfdc9e8f2f836fb95ab
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3791061
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82260}

The `num_functions_` counter got incremented at the exit of
`ProcessFunctionBody`, and for some exits it did not get incremented
at all. This was incorrect, it has to get incremented for each call to
`ProcessFunctionBody`. With this CL, `num_functions_` gets called at
the beginning of the function.

R=clemensb@chromium.org

Bug: v8:12852
Change-Id: I554916a7217533234a82ba397c301b926ce86b99
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811587
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82259}

[turbofan][arm64] Replace TruncateInt64ToInt32(BitcastTaggedToWordForTagAndSmiBits(Load(x))) with Load(x)

This allows arm64 to produce an extending load from ChangeInt32ToInt64(Load(x)) more frequently.
Reduces embedded code size by 0.66% for arm64.

This change gives 0.3% for Speedometer on an A55 machine.

Change-Id: Ie27a134cea3dfc8a26b87553f27ca01bf9f00f1a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3803227Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: George Wort <george.wort@arm.com>
Cr-Commit-Position: refs/heads/main@{#82258}

Many messages already do not end in a ".", which makes sense for
embedders that format location and message in one line, like Chrome.

Before:
  V8 error: Empty MaybeLocal. (v8::ToLocalChecked).

After:
  V8 error: Empty MaybeLocal (v8::ToLocalChecked).

R=mlippautz@chromium.org

Change-Id: Ibfb226c50ae8dce4057cdf0012e58fa1f27faa2a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811586Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82257}

Some tests assume lazy compilation is disabled.

Bug: v8:12852
Change-Id: I8e7bf0b7beeecf4ac385a458d7a178d0aa9cdbca
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811292Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82256}

In release builds, FLAG_debug_code is statically false. Without LTO,
this information is not available to callers of the various Assert
functions though.
This CL defines the methods as empty if V8_ENABLE_DEBUG_CODE is not set.
This removes some calls from non-LTO builds, and might even slightly
improve LTO builds if we enable more optimizations earlier in the
pipeline.

R=tebbi@chromium.org

Change-Id: I93a8f2f6322053e56f3d0fd8aae73cc3dd62d6ea
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3805887
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82255}

JSTypedArray needs the base_pointer ByteArray immediately
if it's on heap. JSTypedArray's base_pointer was initialized
to Smi::uninitialized_deserialization_value at first when
deserializing, and if base_pointer was deferred, we will
mistakenly check JSTypedArray not on heap.

Bug: v8:13149
Change-Id: I104c83ff9a2017de1c8071a9e116baa602f6977d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3813068Reviewed-by: Jakob Linke <jgruber@chromium.org>
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Cr-Commit-Position: refs/heads/main@{#82254}

Bug: v8:7700
Change-Id: I3547c06a6f90ea1243b76a9967574d6c2afd0af9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3813712
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82253}

Bug: v8:7700
Change-Id: Iaff0bf8d3ed1510bd9d8605932905bee9341e33f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3815483
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82252}

We could throw proxy revoked error before calling
Array.IsArray to make error message clearer.

Bug: v8:13037
Change-Id: I85055d24c833acd25791ef7a8a394955805ff3f1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3813065Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Cr-Commit-Position: refs/heads/main@{#82251}

Bug: v8:7700
Change-Id: Iad4b8c8187dc99e811a90f66b05d0cd9e2713ec9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3815484Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: 王澳 <wangao.james@bytedance.com>
Cr-Commit-Position: refs/heads/main@{#82250}

Bug: v8:7700
Change-Id: Ifa3c78017abf8f596a7d3c96877ca035d6126c90
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3815481
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82249}

This CL adds three metrics for lazy compilation: the number of functions
compiled lazily, the total time spent on compiling functions lazily,
and the maximum time spent on compiling a single function. All three
metrics get recorded twice, once 5 seconds after instantiation, and once
20 seconds after instantiation.

R=clemensb@chromium.org

Bug: v8:12852
Change-Id: Ib9e5e12921fb1ec7aefd53af604cbb389bee79b9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811502Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82248}

This CL enables Myers algorithm introduced with
https://crrev.com/c/3804860.

Note that Myers finds slightly different diffs in some cases compared
to the current approach so this CL has to rebaseline one test.

R=kimanh@chromium.org

Bug: chromium:1205288
Change-Id: Ife4708a9edf543db938024a5e14c34a589d6a22a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3810244Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82247}

Wasm counters were accidentally changed to use NestedTimedHistograms in
https://crrev.com/c/3080566.
Revert that, and fix a comment in the NESTED_TIMED_HISTOGRAM_LIST macro
list.

R=cbruni@chromium.org

Change-Id: Ib28fbf50781026fe28c22af6108c88c3634d92c0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811584
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82246}

Bug: v8:7700
Change-Id: Ib3f799f37110ea6ba56417d868a25794abbfa08b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3813071
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82245}

This reverts commit 6ca3adb9.

Reason for revert: Build failed with V8_MAP_PACKING

Original change's description:
> [ptr-compr][x64][compiler] Support load map in compressed form
>
> ...to allow pointer decompression at use-site.
>
> Bug: v8:13056, v8:7703
> Change-Id: If369286814c76340a945cc2a9fd863888a813080
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811737
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Hao A Xu <hao.a.xu@intel.com>
> Cr-Commit-Position: refs/heads/main@{#82242}

Bug: v8:13056, v8:7703
Change-Id: I01b6ea880c656b66392cb8eb47f7c80d8c0e4936
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3815777
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82244}

This CL adds a new diffing implementation based on Myers algorithm
to live editing. We straight-up implement the algorithm presented in
"Myers, E.W. An O(ND) difference algorithm and its variations (1986)"
particularly the "Linear space refinement" presented in section 4b.

Note that the CL does not enable the new algorithm straight-away.
We'll land a separate CL for easier revertability.

Myers algorithm is a great improvement over the current dynamic
programming approach. Local benchmarking with a 130kB script
has shown drastic improvements both for time and space:

    Live editing script (Old line count 10236 vs New 10240)
    Dynamic Programming: 65701.931 ms
    Myers:               11.735 ms

Bug: chromium:1205288
Change-Id: I136f176f4a0d3c9a5dcd7a157c72c49c475bea19
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3804860Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82243}

...to allow pointer decompression at use-site.

Bug: v8:13056, v8:7703
Change-Id: If369286814c76340a945cc2a9fd863888a813080
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811737Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Hao A Xu <hao.a.xu@intel.com>
Cr-Commit-Position: refs/heads/main@{#82242}

Change-Id: I5d6636591912694cd0d0897f62c7ab56f0107b99
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3813425
Auto-Submit: Yahan Lu <yahan@iscas.ac.cn>
Commit-Queue: ji qiu <qiuji@iscas.ac.cn>
Reviewed-by: ji qiu <qiuji@iscas.ac.cn>
Cr-Commit-Position: refs/heads/main@{#82241}

Some wasm interpreter tests are failing since instructions generated
by gcc such as *multiply and and* (fmadds) create intermediate
results bigger than 8 bytes which doesn't match other architectures,
hence the resulting output differs.

Port commit 13314a20

co-authors: Jun Yuan Tan <junyuan.tan@starfivetech.com>

Change-Id: I18c0b659f30df84bb30daa176368a7e81b51063e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3811139
Commit-Queue: Yahan Lu <yahan@iscas.ac.cn>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82240}

Bug: v8:11092
Change-Id: Ic0f30c35dfc4acda286c157722eb794a0aa4a360
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3814072
Commit-Queue: Paolo Severini <paolosev@microsoft.com>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82239}