Returning `std::array<uint8_t, N>` is better ergonomics for the hashing functions usage, instead of a `StringRef`:
* When returning `StringRef`, client code is "jumping through hoops" to do string manipulations instead of dealing with fixed array of bytes directly, which is more natural
* Returning `std::array<uint8_t, N>` avoids the need for the hasher classes to keep a field just for the purpose of wrapping it and returning it as a `StringRef`
As part of this patch also:
* Introduce `TruncatedBLAKE3` which is useful for using BLAKE3 as the hasher type for `HashBuilder` with non-default hash sizes.
* Make `MD5Result` inherit from `std::array<uint8_t, 16>` which improves & simplifies its API.
Differential Revision: https://reviews.llvm.org/D123100
BLAKE3 is a cryptographic hash function that is secure and very performant.
The C implementation originates from https://github.com/BLAKE3-team/BLAKE3/tree/1.3.1/c
License is at https://github.com/BLAKE3-team/BLAKE3/blob/1.3.1/LICENSE
This patch adds:
* `llvm/include/llvm-c/blake3.h`: The BLAKE3 C API
* `llvm/include/llvm/Support/BLAKE3.h`: C++ wrapper of the C API
* `llvm/lib/Support/BLAKE3`: Directory containing the BLAKE3 C implementation files, including the `LICENSE` file
* `llvm/unittests/Support/BLAKE3Test.cpp`: unit tests for the BLAKE3 C++ wrapper
This initial patch contains the pristine BLAKE3 sources, a follow-up patch will introduce
LLVM-specific prefixes to avoid conflicts if a client also links with its own BLAKE3 version.
And here's some timings comparing BLAKE3 with LLVM's SHA1/SHA256/MD5.
Timings include `AVX512`, `AVX2`, `neon`, and the generic/portable implementations.
The table shows the speed-up multiplier of BLAKE3 for hashing 100 MBs:
| Processor | SHA1 | SHA256 | MD5 |
|-------------------------|-------|--------|------|
| Intel Xeon W (AVX512) | 10.4x | 27x | 9.4x |
| Intel Xeon W (AVX2) | 6.5x | 17x | 5.9x |
| Intel Xeon W (portable) | 1.3x | 3.3x | 1.1x |
| M1Pro (neon) | 2.1x | 4.7x | 2.8x |
| M1Pro (portable) | 1.1x | 2.4x | 1.5x |
Differential Revision: https://reviews.llvm.org/D121510
Argyrios Kyrtzidis