Removing prefetch operations as per the vote in the github issue:
https://github.com/WebAssembly/simd/pull/352

Bug:v8:11168

Change-Id: Ia72684e68ce886f8f26a7d3b5bea601be416dfab
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2771758Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73578}

Prototype 2 prefetch instructions (temporal and non-temporal) on arm64
and interpreter.

Add prfm to assembler, and use MiscField to encode the two versions.
Small tweak to simulator to handle these new instructions (no-op).

The implementation in the interpreter just pops the memory index and
does nothing.

Simple test cases added for these 2 new instructions, as well as a
prefetch with OOB index, which should not trap.

Bug: v8:11168
Change-Id: Ieced8081615d07f950d6d4c1128d1bc6a75839fd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2543167Reviewed-by: Bill Budge <bbudge@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71353}

Bug: v8:10927
Change-Id: Icbdc0d7329ddd466e7d67a954246a35795b4dece
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2507310
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71220}

Bug: v8:10799
Change-Id: Id912520b6a27e439e204bac47c0723a8f613be4b
Fixed: v8:10799
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2472000
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70656}

The C++ code uses the A instruction key for return address signing,
which is the default for Clang and GCC when the -mbranch-protection
option is used (although this can be configured to use the B key).

Using the B key for JS means that it's not possible to use an A key
signing gadget to replace a return address signed with the B key and
vice-versa. This should offer a degree of separation from the C++ side.

Bug: v8:10026
Change-Id: Ia9dcc7ae7096c96b4a271efbe25fc02940f6fc8e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2242953Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Cr-Commit-Position: refs/heads/master@{#68360}

This includes the instruction opcode, its use in TF, its support in the
simulator and the detection of the associated CPU feature.

The instruction can be tested in the simulator with the new
--sim-arm64-optional-features flag.

Change-Id: I6047fa16696394fe0ced4535f7788d2c8716a18c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2222348Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68261}

NEONFormatDecoder::Substitute function utilizes snprintf()
to substitute arrangement specifier into a format string.
Some instruction format strings (e.i. ld4r) are specified
with '%n$' positional parameter fields, but on Windows
snprintf function doesn't support these parameters.
NEONFormatDecoder logic is extended to handle four parameters
in order to avoid using positional parameters.

Bug: v8:10365
Change-Id: I79d4014c6b45d698ca47090a74c30e4eae856334
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2148776Reviewed-by: Martyn Capewell <martyn.capewell@arm.com>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67201}

Bug: v8:10026
Change-Id: I8ee836ee6298415a21cf487bc3d0e5f803fc6186
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1965590
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66082}

Just use the default {is_valid} method provided by RegisterBase.

Drive-by: Also rename {CPURegList::IsValid} to {CPURegList::is_valid}.

R=mstarzinger@chromium.org

Bug: v8:9810
Change-Id: Ia3bc3c477e6329d63ffd00bca59762d9a6cf2fcc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1916201
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64952}

The {CountTrailingZeros} function is at least on one hot code path,
and there it causes significant overhead. With this CL I just call the
base::bit:: version of {CountTrailingZeros} directly. This allows the
compiler to compile it to a single hardware instruction.

R=v8-arm-ports@googlegroups.com

Bug: v8:9396
Change-Id: I81eccc5fce9b9856d41c503bd1e4a07287eb6e1e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1803648
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Martyn Capewell <martyn.capewell@arm.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63831}

Bug: v8:3770,v8:9666
Change-Id: I7b7652887d6b60fbb80e1100834bc7c9df0544d8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1792909
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Martyn Capewell <martyn.capewell@arm.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63801}

Change-Id: I29c88d9e5de34e9a940b76ab76a40376d251c25f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1373781
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62901}

Bug: v8:9247
Change-Id: I2f999ed3a8cc0931e5092f2ac6e709b8ff3f9e42
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1630678
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61896}