[wasm-ld] Switch to xxh3_64bits

[MaskRay]

Summary

Similar to recent changes to ELF (e.g., D154813), Mach-O, and COFF to
improve hashing performance.

[dschuff]

Thanks!

lld/test/wasm/build-id.test

.section .data.foo,"",@
         .hidden  foo
         .p2align        2
 foo:
         .int32  1
         .size   foo, 4
 
 
 # DEFAULT:      Contents of section build_id:
-# DEFAULT-NEXT: 0000 10cdbf99 f76b1f5e ebb2f36a 1bde1d6c  .....k.^...j...l
-# DEFAULT-NEXT: 0010 01
+# DEFAULT-NEXT: 0000 100e228e 4e2fa853 6393b43d ed1d4676
+# DEFAULT-NEXT: 0010 13 .
 
 # SHA1:      Contents of section build_id:
 # SHA1-NEXT: 0000 14ad22e8 54d72438 94af85de 3c5592bd  ..".T.$8....<U..
 # SHA1-NEXT: 0010 1b5ec96f 6b                          .^.ok
 
 # UUID:      Contents of section build_id:
 # UUID-NEXT: 0000 10
 
 # HEX:      Contents of section build_id:
 # HEX-NEXT:  0000 04123456 78                          ..4Vx
 
 
 # NONE-NOT: Contents of section build_id:

lld/wasm/InputChunks.cpp

void MergeInputChunk::splitStrings(ArrayRef<uint8_t> data) {
   StringRef s = toStringRef(data);
 
   while (!s.empty()) {
     size_t end = s.find(0);
     if (end == StringRef::npos)
       fatal(toString(this) + ": string is not null terminated");
     size_t size = end + 1;
 
-    pieces.emplace_back(off, xxHash64(s.substr(0, size)), true);
+    pieces.emplace_back(off, xxh3_64bits(s.substr(0, size)), true);
     s = s.substr(size);
     off += size;
   }
 }
 
 // This function is called after we obtain a complete list of input sections
 // that need to be linked. This is responsible to split section contents
 // into small chunks for further processing.

lld/wasm/Writer.cpp

void Writer::writeBuildId() {
   size_t hashSize = out.buildIdSec->hashSize;
   std::vector<uint8_t> buildId(hashSize);
   llvm::ArrayRef<uint8_t> buf{buffer->getBufferStart(), size_t(fileSize)};
 
   switch (config->buildId) {
   case BuildIdKind::Fast: {
     std::vector<uint8_t> fileHash(8);
     computeHash(fileHash, buf, [](uint8_t *dest, ArrayRef<uint8_t> arr) {
-      support::endian::write64le(dest, xxHash64(arr));
+      support::endian::write64le(dest, xxh3_64bits(arr));
     });
     makeUUID(5, fileHash, buildId);
     break;
   }
   case BuildIdKind::Sha1:
     computeHash(buildId, buf, [&](uint8_t *dest, ArrayRef<uint8_t> arr) {
       memcpy(dest, SHA1::hash(arr).data(), hashSize);
     });