A previous commit (82f75ed) made clang ignore .gch files that were not
Clang AST files. This broke `-gmodules`, which embeds the Clang AST into
an object file containing debug info.

This changes the probing to detect any file format recognized by
`llvm::identify_magic()` as potentially containing a Clang AST.

Previous PR: https://github.com/llvm/llvm-project/pull/69204

Summary:
More SPIR-V related patches are being upstreamed. We should add support
to detect when a binary file is SPIR-V. This will be used in the future
when support for SPIR-V is added to the offloading runtime or more
support for bundling.

The magic number is described in the official documentation:
https://registry.khronos.org/SPIR-V/specs/1.0/SPIRV.html#Magic. Notably,
SPIR-V files are streams of 32-bit words. This means that the magic
numbers differ depending on the endianness. Here we simply check the
strandard and byte-reversed versions.

This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.

I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.

Original PR: https://github.com/llvm/llvm-project/pull/67162

The commit was reverted due to UB detected by santizer:

https://lab.llvm.org/buildbot/#/builders/238/builds/5955

clang/lib/Driver/OffloadBundler.cpp:1012:25: runtime error:
 load of misaligned address 0xaaaae2d90e7c for type
 'const uint64_t' (aka 'const unsigned long'), which
 requires 8 byte alignment

It was fixed by using memcpy instead of dereferencing int*
casted from unaligned char*.

This reverts commit a1e81d2ead02e041471ec2299d7382f80c4dbba6.

Revert "Fix test hip-offload-compress-zlib.hip"

This reverts commit ba01ce60665848478ba4e76190907153a8c26fe9.

Revert due to sanity fail at

https://lab.llvm.org/buildbot/#/builders/5/builds/37188

https://lab.llvm.org/buildbot/#/builders/238/builds/5955

/b/sanitizer-aarch64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Driver/OffloadBundler.cpp:1012:25: runtime error: load of misaligned address 0xaaaae2d90e7c for type 'const uint64_t' (aka 'const unsigned long'), which requires 8 byte alignment
0xaaaae2d90e7c: note: pointer points here
  bc 00 00 00 94 dc 29 9a  89 fb ca 2b 78 9c 8b 8f  77 f6 71 f4 73 8f f7 77  73 f3 f1 77 74 89 77 0a
              ^
    #0 0xaaaaba125f70 in clang::CompressedOffloadBundle::decompress(llvm::MemoryBuffer const&, bool) /b/sanitizer-aarch64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Driver/OffloadBundler.cpp:1012:25
    #1 0xaaaaba126150 in clang::OffloadBundler::ListBundleIDsInFile(llvm::StringRef, clang::OffloadBundlerConfig const&) /b/sanitizer-aarch64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Driver/OffloadBundler.cpp:1089:7

Will reland after fixing it.

Add option -f[no-]offload-compress to clang to enable/disable
compression of device binary for HIP. By default it is disabled.

Add option -compress to clang-offload-bundler to enable compression of
offload bundle. By default it is disabled.

When enabled, zstd or zlib is used for compression when available.

When disabled, it is NFC compared to previous behavior. The same offload
bundle format is used as before.

Clang-offload-bundler automatically detects whether the input file to be
unbundled is compressed and the compression method and decompress if
necessary.

Similar to D125411, but for ARM64X.

ARM64X PE binaries are hybrids containing both ARM64EC and pure ARM64
variants in one file. They are usually linked by passing separate
ARM64EC and ARM64 object files to linker. Linked binaries use ARM64
machine and contain additional CHPE metadata in their load config.
CHPE metadata support is not part of this patch, I plan to send that later.

Using ARM64X as a machine type of object files themselves is somewhat
ambiguous, but such files are allowed by MSVC. It treats them as ARM64
or ARM64EC object, depending on the context. Such objects can be
produced with cvtres.exe -machine:arm64x.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D148517

This includes handling of new attributes for symbols & rpath.
In the event that an older format file is compared to tbd_v5, ignore these new attributes.

Reviewed By: ributzka

Differential Revision: https://reviews.llvm.org/D144529

This is the first patch of a patchset to add initial support for
ARM64EC. Basic documentation is available at
https://docs.microsoft.com/en-us/windows/uwp/porting/arm64ec-abi .
(Discourse post:
https://discourse.llvm.org/t/initial-patches-for-arm64ec-windows-11-now-posted/62449
.)

The file format for ARM64EC is basically identical to normal ARM64.
There are a few extra sections, but the existing code for reading ARM64
object files just works.

Differential Revision: https://reviews.llvm.org/D125411

https://reviews.llvm.org/D131909