From 6b8d872e5e2dd68a5229ec55f5261dae34ff9bdb Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Tue, 18 Jul 2017 01:06:11 -0700
Subject: Protect SSE4 code behind a compile-time flag

---
 src/Makefile.am       | 5 ++++-
 src/crypto/sha256.cpp | 4 +++-
 2 files changed, 7 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/Makefile.am b/src/Makefile.am
index 35bfeb466c..f7abab482e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -263,11 +263,14 @@ crypto_libbitcoin_crypto_a_SOURCES = \
   crypto/sha1.cpp \
   crypto/sha1.h \
   crypto/sha256.cpp \
-  crypto/sha256_sse4.cpp \
   crypto/sha256.h \
   crypto/sha512.cpp \
   crypto/sha512.h
 
+if EXPERIMENTAL_ASM
+crypto_libbitcoin_crypto_a_SOURCES += crypto/sha256_sse4.cpp
+endif
+
 # consensus: shared between all executables that validate any consensus rules.
 libbitcoin_consensus_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
 libbitcoin_consensus_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
diff --git a/src/crypto/sha256.cpp b/src/crypto/sha256.cpp
index 25f4eabd4c..15d6db90c2 100644
--- a/src/crypto/sha256.cpp
+++ b/src/crypto/sha256.cpp
@@ -10,12 +10,14 @@
 #include <atomic>
 
 #if defined(__x86_64__) || defined(__amd64__)
+#if defined(EXPERIMENTAL_ASM)
 #include <cpuid.h>
 namespace sha256_sse4
 {
 void Transform(uint32_t* s, const unsigned char* chunk, size_t blocks);
 }
 #endif
+#endif
 
 // Internal implementation code.
 namespace
@@ -176,7 +178,7 @@ TransformType Transform = sha256::Transform;
 
 std::string SHA256AutoDetect()
 {
-#if defined(__x86_64__) || defined(__amd64__)
+#if defined(EXPERIMENTAL_ASM) && (defined(__x86_64__) || defined(__amd64__))
     uint32_t eax, ebx, ecx, edx;
     if (__get_cpuid(1, &eax, &ebx, &ecx, &edx) && (ecx >> 19) & 1) {
         Transform = sha256_sse4::Transform;
-- 
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