Add LSH dynamic dispatch (PR #1032)

This commit adds dynamic dispatch to LSH. The implementation pivots on AVX2 and SSSE3.

1 files changed, 23 insertions, 8 deletions

diff --git a/lsh.h b/lsh.h
index 68284f97..2f9918d8 100644
--- a/lsh.h
+++ b/lsh.h
@@ -4,6 +4,11 @@
 //         see https://seed.kisa.or.kr/kisa/algorithm/EgovLSHInfo.do

 //         and https://seed.kisa.or.kr/kisa/Board/22/detailView.do.

 

+// We are hitting some sort of GCC bug in the LSH AVX2 code path.

+// Clang is OK on the AVX2 code path. We believe it is GCC Issue

+// 82735, https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82735. It

+// makes using zeroupper a little tricky.

+

 /// \file lsh.h

 /// \brief Classes for the LSH hash functions

 /// \since Crypto++ 8.6

@@ -15,6 +20,12 @@
 #include "cryptlib.h"

 #include "secblock.h"

 

+// Enable SSE2 and AVX2 for 64-bit machines.

+// 32-bit machines slow down with SSE2.

+#if (CRYPTOPP_BOOL_X32) || (CRYPTOPP_BOOL_X64)

+# define CRYPTOPP_ENABLE_64BIT_SSE 1

+#endif

+

 NAMESPACE_BEGIN(CryptoPP)

 

 /// \brief LSH-224 and LSH-256 hash base class

@@ -34,14 +45,14 @@ public:
 	unsigned int OptimalDataAlignment() const { return GetAlignmentOf<word32>(); }

 

 	void Restart();

-	void Update(const byte *input, size_t length);

+	void Update(const byte *input, size_t size);

 	void TruncatedFinal(byte *hash, size_t size);

 

 	std::string AlgorithmProvider() const;

 

 protected:

 	LSH256_Base(unsigned int algType, unsigned int digestSize)

-		: m_algType(algType), m_digestSize(digestSize) {}

+		: m_digestSize(digestSize) { m_state[80] = algType; }

 

 protected:

 	// Working state is:

@@ -52,8 +63,10 @@ protected:
 	//   * submsg_o_l = 8 32-bit words

 	//   * submsg_o_r = 8 32-bit words

 	//   * last_block = 32 32-bit words (128 bytes)

-	FixedSizeSecBlock<word32, 80> m_state;

-	word32 m_algType, m_remainingBitLength;

+	//   * algType

+	//   * remainingBitLength

+	FixedSizeSecBlock<word32, 80+2> m_state;

+	// word32 m_algType, m_remainingBitLength;

 	word32 m_digestSize;

 };

 

@@ -132,14 +145,14 @@ public:
 	unsigned int OptimalDataAlignment() const { return GetAlignmentOf<word64>(); }

 

 	void Restart();

-	void Update(const byte *input, size_t length);

+	void Update(const byte *input, size_t size);

 	void TruncatedFinal(byte *hash, size_t size);

 

 	std::string AlgorithmProvider() const;

 

 protected:

 	LSH512_Base(unsigned int algType, unsigned int digestSize)

-		: m_algType(algType), m_digestSize(digestSize) {}

+		: m_digestSize(digestSize) { m_state[80] = algType; }

 

 protected:

 	// Working state is:

@@ -150,8 +163,10 @@ protected:
 	//   * submsg_o_l = 8 64-bit words

 	//   * submsg_o_r = 8 64-bit words

 	//   * last_block = 32 64-bit words (256 bytes)

-	FixedSizeSecBlock<word64, 80> m_state;

-	word32 m_algType, m_remainingBitLength;

+	//   * algType

+	//   * remainingBitLength

+	FixedSizeSecBlock<word64, 80+2> m_state;

+	// word32 m_algType, m_remainingBitLength;

 	word32 m_digestSize;

 };