Re-enable Salsa20 ASM (GH weidai11#543)

We are fairly certain this is a false positive due to glibc's __memcmp_sse4_1.

Author: noloader

datatest.cpp

@@ -116,12 +116,8 @@ void PutDecodedDatumInto(const TestData &data, const char *name, BufferedTransfo
 			s1 = s1.substr(s1.find(' ')+1);
 		}
 
-		// Convert endian order. Use it with 64-bit words like this:
-		//   Key: word64 BC2560EFC6BBA2B1 E3361F162238EB40 FB8631EE0ABBD175 7B9479D4C5479ED1
-		//   BC2560EFC6BBA2B1 will be processed into B1A2BBC6EF6025BC.
-		// or:
-		//   Key: word32 BC2560EF E3361F16 FB8631EE 7B9479D4
-		//   BC2560EF will be processed into EF6025BC.
+		// Convert word32 or word64 to little endian order. Some algorithm test vectors are
+		// presented in the format. We probably should have named them word32le and word64le.
 		if (s1.length() >= 6 && (s1.substr(0,6) == "word32" || s1.substr(0,6) == "word64"))
 		{
 			std::istringstream iss(s1.substr(6));
@@ -489,16 +485,7 @@ void TestSymmetricCipher(TestData &v, const NameValuePairs &overrideParameters)
 				static_cast<BlockPaddingSchemeDef::BlockPaddingScheme>(paddingScheme));
 		RandomizedTransfer(StringStore(plaintext).Ref(), encFilter, true);
 		encFilter.MessageEnd();
-		/*{
-			std::string z;
-			encryptor->Seek(seek);
-			StringSource ss(plaintext, false, new StreamTransformationFilter(*encryptor, new StringSink(z),
-					static_cast<BlockPaddingSchemeDef::BlockPaddingScheme>(paddingScheme)));
-			while (ss.Pump(64)) {}
-			ss.PumpAll();
-			for (int i=0; i<z.length(); i++)
-				CRYPTOPP_ASSERT(encrypted[i] == z[i]);
-		}*/
+
 		if (test != "EncryptXorDigest")
 			ciphertext = GetDecodedDatum(v, "Ciphertext");
 		else

salsa.cpp

@@ -74,7 +74,7 @@ void Salsa20_Policy::SeekToIteration(lword iterationCount)
 	m_state[5] = (word32)SafeRightShift<32>(iterationCount);
 }
 
-#if (CRYPTOPP_BOOL_X86 || CRYPTOPP_BOOL_X32 || CRYPTOPP_BOOL_X64) && !defined(CRYPTOPP_DISABLE_SALSA_ASM)
+#if (CRYPTOPP_BOOL_X86 || CRYPTOPP_BOOL_X32 || CRYPTOPP_BOOL_X64)
 unsigned int Salsa20_Policy::GetAlignment() const
 {
 #if CRYPTOPP_SSE2_ASM_AVAILABLE

salsa.h

@@ -12,7 +12,7 @@
 // TODO: work around GCC 4.8+ issue with SSE2 ASM until the exact details are known
 //   and fix is released. Duplicate with "valgrind ./cryptest.exe tv salsa"
 // "Inline assembly operands don't work with .intel_syntax", http://llvm.org/bugs/show_bug.cgi?id=24232
-#if CRYPTOPP_BOOL_X32 || defined(CRYPTOPP_DISABLE_INTEL_ASM) || (CRYPTOPP_GCC_VERSION >= 40800)
+#if CRYPTOPP_BOOL_X32 || defined(CRYPTOPP_DISABLE_INTEL_ASM)
 # define CRYPTOPP_DISABLE_SALSA_ASM
 #endif
 
@@ -22,7 +22,7 @@ NAMESPACE_BEGIN(CryptoPP)
 //! \brief Salsa20 stream cipher information
 struct Salsa20_Info : public VariableKeyLength<32, 16, 32, 16, SimpleKeyingInterface::UNIQUE_IV, 8>
 {
-	CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "Salsa20";}
+	static std::string StaticAlgorithmName() {return "Salsa20";}
 };
 
 //! \class Salsa20_Policy
@@ -35,7 +35,7 @@ class CRYPTOPP_NO_VTABLE Salsa20_Policy : public AdditiveCipherConcretePolicy<wo
 	void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length);
 	bool CipherIsRandomAccess() const {return true;}
 	void SeekToIteration(lword iterationCount);
-#if (CRYPTOPP_BOOL_X86 || CRYPTOPP_BOOL_X32 || CRYPTOPP_BOOL_X64) && !defined(CRYPTOPP_DISABLE_SALSA_ASM)
+#if (CRYPTOPP_BOOL_X86 || CRYPTOPP_BOOL_X32 || CRYPTOPP_BOOL_X64)
 	unsigned int GetAlignment() const;
 	unsigned int GetOptimalBlockSize() const;
 #endif
@@ -58,7 +58,7 @@ struct Salsa20 : public Salsa20_Info, public SymmetricCipherDocumentation
 //! \brief XSalsa20 stream cipher information
 struct XSalsa20_Info : public FixedKeyLength<32, SimpleKeyingInterface::UNIQUE_IV, 24>
 {
-	CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "XSalsa20";}
+	static std::string StaticAlgorithmName() {return "XSalsa20";}
 };
 
 //! \class XSalsa20_Policy