1 files changed, 63 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/scudo/standalone/checksum.h b/contrib/llvm-project/compiler-rt/lib/scudo/standalone/checksum.h
new file mode 100644
index 000000000000..32ca372b097f
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/scudo/standalone/checksum.h
@@ -0,0 +1,63 @@
+//===-- checksum.h ----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SCUDO_CHECKSUM_H_
+#define SCUDO_CHECKSUM_H_
+
+#include "internal_defs.h"
+
+// Hardware CRC32 is supported at compilation via the following:
+// - for i386 & x86_64: -mcrc32 (earlier: -msse4.2)
+// - for ARM & AArch64: -march=armv8-a+crc or -mcrc
+// An additional check must be performed at runtime as well to make sure the
+// emitted instructions are valid on the target host.
+
+#if defined(__CRC32__)
+// NB: clang has <crc32intrin.h> but GCC does not
+#include <smmintrin.h>
+#define CRC32_INTRINSIC                                                        \
+  FIRST_32_SECOND_64(__builtin_ia32_crc32si, __builtin_ia32_crc32di)
+#elif defined(__SSE4_2__)
+#include <smmintrin.h>
+#define CRC32_INTRINSIC FIRST_32_SECOND_64(_mm_crc32_u32, _mm_crc32_u64)
+#endif
+#ifdef __ARM_FEATURE_CRC32
+#include <arm_acle.h>
+#define CRC32_INTRINSIC FIRST_32_SECOND_64(__crc32cw, __crc32cd)
+#endif
+#ifdef __loongarch__
+#include <larchintrin.h>
+#define CRC32_INTRINSIC FIRST_32_SECOND_64(__crcc_w_w_w, __crcc_w_d_w)
+#endif
+
+namespace scudo {
+
+enum class Checksum : u8 {
+  BSD = 0,
+  HardwareCRC32 = 1,
+};
+
+// BSD checksum, unlike a software CRC32, doesn't use any array lookup. We save
+// significantly on memory accesses, as well as 1K of CRC32 table, on platforms
+// that do no support hardware CRC32. The checksum itself is 16-bit, which is at
+// odds with CRC32, but enough for our needs.
+inline u16 computeBSDChecksum(u16 Sum, uptr Data) {
+  for (u8 I = 0; I < sizeof(Data); I++) {
+    Sum = static_cast<u16>((Sum >> 1) | ((Sum & 1) << 15));
+    Sum = static_cast<u16>(Sum + (Data & 0xff));
+    Data >>= 8;
+  }
+  return Sum;
+}
+
+bool hasHardwareCRC32();
+WEAK u32 computeHardwareCRC32(u32 Crc, uptr Data);
+
+} // namespace scudo
+
+#endif // SCUDO_CHECKSUM_H_