Use arm64/x86_64 ISA extensions to compute CRC32C

src/workerd/api/crypto/crc-impl.c++

@@ -55,8 +55,10 @@ constexpr std::array<T, crcTableSize> gen_crc_table(T polynomial, bool reflectIn
   return crcTable;
 }
 
+#if !(__CRC32__ || __ARM_FEATURE_CRC32)
 // https://reveng.sourceforge.io/crc-catalogue/all.htm#crc.cat.crc-32-iscsi
 constexpr auto crc32c_table = gen_crc_table(static_cast<uint32_t>(0x1edc6f41), true, true);
+#endif
 // https://reveng.sourceforge.io/crc-catalogue/all.htm#crc.cat.crc-64-nvme
 constexpr auto crc64nvme_table =
     gen_crc_table(static_cast<uint64_t>(0xad93d23594c93659), true, true);
@@ -67,8 +69,30 @@ uint32_t crc32c(uint32_t crc, const uint8_t *data, unsigned int length) {
     return 0;
   }
   crc ^= 0xffffffff;
+#if __CRC32__ || __ARM_FEATURE_CRC32
+  // Using hardware acceleration, process data in 8-byte chunks. Any remaining bytes are processed
+  // one-by-one in the main loop.
+  while (length >= 8) {
+    // 8-byte unaligned read
+    uint64_t val = *(uint64_t *)data;
+#if __ARM_FEATURE_CRC32
+    crc = __builtin_arm_crc32cd(crc, val);
+#else
+    crc = __builtin_ia32_crc32di(crc, val);
+#endif
+    length -= 8;
+    data += 8;
+  }
+#endif
+
   while (length--) {
+#if __ARM_FEATURE_CRC32
+    crc = __builtin_arm_crc32cb(crc, *data++);
+#elif __CRC32__
+    crc = __builtin_ia32_crc32qi(crc, *data++);
+#else
     crc = crc32c_table[(crc ^ *data++) & 0xffL] ^ (crc >> 8);
+#endif
   }
   return crc ^ 0xffffffff;
 }

src/workerd/api/crypto/crypto.c++

@@ -734,7 +734,7 @@ class CRC64NVMEDigestContext final: public DigestContext {
 
   kj::Array<kj::byte> close() override {
     auto beValue = htobe64(value);
-    static_assert(sizeof(value) == sizeof(beValue), "CRC32 digest is not 32 bits?");
+    static_assert(sizeof(value) == sizeof(beValue), "CRC64 digest is not 64 bits?");
     auto digest = kj::heapArray<kj::byte>(sizeof(beValue));
     KJ_DASSERT(digest.size() == sizeof(beValue));
     memcpy(digest.begin(), &beValue, sizeof(beValue));

src/workerd/api/crypto/endianness.h

@@ -6,8 +6,8 @@
 #include <stdint.h>
 
 // This file provides cross platform support for endianness conversions.
-// It is intended to hide away the poluting includes of system headers to provide the functions
-// without poluting the global namespace.
+// It is intended to hide away the polluting includes of system headers to provide the functions
+// without polluting the global namespace.
 
 uint16_t htobe16(uint16_t x);
 uint16_t htole16(uint16_t x);

src/workerd/io/BUILD.bazel

@@ -80,6 +80,16 @@ wd_cc_library(
         ":set_enable_experimental_webgpu": ["//src/workerd/api/gpu:hdrs"],
         "//conditions:default": [],
     }),
+    # global CPU-specific options are inconvenient to specify with bazel – just set the options we
+    # need for CRC32C in this target for now.
+    copts = select({
+        "@platforms//cpu:aarch64": [
+            "-mcrc",
+        ],
+        "@platforms//cpu:x86_64": [
+            "-msse4.2",
+        ],
+    }),
     defines = select({
         ":set_enable_experimental_webgpu": ["WORKERD_EXPERIMENTAL_ENABLE_WEBGPU"],
         "//conditions:default": [],