[Support/Hash functions] Change the `final()` and `result()` of the hashing functions to return an array of bytes

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

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp b/llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp
index fdb07cf282a9..f291827d7f6f 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp
@@ -903,7 +903,7 @@ Error BitcodeAnalyzer::parseBlock(unsigned BlockID, unsigned IndentLevel,
         else {
           // Recompute the hash and compare it to the one in the bitcode
           SHA1 Hasher;
-          StringRef Hash;
+          std::array<uint8_t, 20> Hash;
           Hasher.update(*CheckHash);
           {
             int BlockSize = (CurrentRecordPos / 8) - BlockEntryPos;
@@ -911,14 +911,14 @@ Error BitcodeAnalyzer::parseBlock(unsigned BlockID, unsigned IndentLevel,
             Hasher.update(ArrayRef<uint8_t>(Ptr, BlockSize));
             Hash = Hasher.result();
           }
-          std::array<char, 20> RecordedHash;
+          std::array<uint8_t, 20> RecordedHash;
           int Pos = 0;
           for (auto &Val : Record) {
             assert(!(Val >> 32) && "Unexpected high bits set");
             support::endian::write32be(&RecordedHash[Pos], Val);
             Pos += 4;
           }
-          if (Hash == StringRef(RecordedHash.data(), RecordedHash.size()))
+          if (Hash == RecordedHash)
             O->OS << " (match)";
           else
             O->OS << " (!mismatch!)";