This reverts commit d3f8105c65046173e20c4c59394b4a7f1bbe7627.

Halide no longer relies on this target:
https://github.com/llvm/llvm-project/pull/98497#issuecomment-2253358685

When `pauthtest` is either passed as environment part of AArch64 Linux
triple
or passed via `-mabi=`, enable the following ptrauth flags:

- `intrinsics`;
- `calls`;
- `returns`;
- `auth-traps`;
- `vtable-pointer-address-discrimination`;
- `vtable-pointer-type-discrimination`;
- `init-fini`.

Some related stuff is still subject to change, and the ABI itself might
be changed, so end users are not expected to use this and the ABI name
has 'test' suffix.

If `-mabi=pauthtest` option is used, it's normalized to effective
triple.

When the environment part of the effective triple is `pauthtest`, try
to use `aarch64-linux-pauthtest` as multilib directory.

The following is not supported:
- combination of `pauthtest` ABI with any branch protection scheme
except BTI;
- explicit set of environment part of the triple to a value different
  from `pauthtest` in combination with `-mabi=pauthtest`;
- usage on non-Linux OS.

---------

Co-authored-by: Anatoly Trosinenko <atrosinenko@accesssoftek.com>

Reverts llvm/llvm-project#98497

We're reverting this for approx 30 days so that the Halide project has
time to transition off the target.

This is a revert of ef5e7f90ea4d5063ce68b952c5de473e610afc02 which was a
temporary partial revert of 77ac823fd285973cfb3517932c09d82e6a32f46d.
The le32 and le64 targets are no longer necessary to retain, so this
removes them entirely.

This reapplies
https://github.com/llvm/llvm-project/commit/195d8ac26d91ca798733c3a5f58d67992d43503d
[DirectX] Fix DXIL part header version encoding. The endian issue was
fixed by
https://github.com/llvm/llvm-project/commit/f42117c8517cc928c6373bad35ebf75d94fe865b.

Move MinorVersion be the lower 8 bit.
Set DXIL version in DXContainerObjectWriter::writeObject.

Fixes #89952

Test failures on big endian bots after this change.

Reverts llvm/llvm-project#91506

Move MinorVersion be the lower 8 bit.
Set DXIL version in DXContainerObjectWriter::writeObject.


Fixes #89952

I'm planning to remove StringRef::equals in favor of
StringRef::operator==.

- StringRef::operator==/!= outnumber StringRef::equals by a factor of
  70 under llvm/ in terms of their usage.

- The elimination of StringRef::equals brings StringRef closer to
  std::string_view, which has operator== but not equals.

- S == "foo" is more readable than S.equals("foo"), especially for
  !Long.Expression.equals("str") vs Long.Expression != "str".

This change set restores commit 080978dd2067d0c9ea7e229aa7696c2480d89ef1 that was reverted to address ASAN
failures and includes a fix for the ASAN failures. 

Following is the description of the change:

An earlier commit provided a way to decouple DXIL version from Shader
Model version by representing the DXIL version as `SubArch` in the DXIL
Target Triple and adding corresponding valid DXIL Arch types.
    
This change constructs DXIL target triple with DXIL version that is
deduced from Shader Model version specified in the following scenarios:
  
1. When compilation target profile is specified:
    For e.g., DXIL target triple `dxilv1.8-unknown-shader6.8-library` is
    constructed when `-T lib_6_8` is specified.
2. When DXIL target triple without DXIL version is specified:
    For e.g., DXIL target triple `dxilv1.8-pc-shadermodel6.8-library` is
    constructed when `-mtriple=dxil-pc-shadermodel6.8-library` is specified.
    
Updated relevant HLSL tests that check for target triple.

Emit named metadata "dx.version" for DXIL version.

Default to DXIL 1.0