From: Daniel M. Weeks <dan@danweeks.net>
Date: Mon, 17 Aug 2015 17:40:12 +0000 (-0700)
Subject: Limit use of hardware crc32 check to SSE 4.2
X-Git-Tag: v0.54.0~1
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=commitdiff_plain;h=ee6b4fce019454e4cde0355c9f084ab1284d41bf

Limit use of hardware crc32 check to SSE 4.2

Summary: Fixes compiling crc32c function on older hardware. (I believe this problem was introduced by 7ec1fc0e0e27ed56c1d18d33af9711a17e9ec750).

Also ensures is in final library since the API suggests it should be. This should correct a number of build problems for other projects like wdt and hhvm when they are compiled using a shared folly library rather than borrowing sources at compile time.
Closes #296

Reviewed By: @yfeldblum

Differential Revision: D2340699

Pulled By: @sgolemon
---

diff --git a/folly/Checksum.cpp b/folly/Checksum.cpp
index a7afa352..d8daf66f 100644
--- a/folly/Checksum.cpp
+++ b/folly/Checksum.cpp
@@ -29,10 +29,11 @@ namespace detail {
   #define __has_builtin(x) 0
 #endif
 
-#if (__has_builtin(__builtin_ia32_crc32qi) && \
+#if __SSE4_2__ && \
+    ((__has_builtin(__builtin_ia32_crc32qi) && \
      __has_builtin(__builtin_ia32_crc32di)) || \
     (FOLLY_X64 && defined(__GNUC__) && defined(__GNUC_MINOR__) && \
-     (((__GNUC__ * 100) + __GNUC_MINOR__) >= 407))
+     (((__GNUC__ * 100) + __GNUC_MINOR__) >= 407)))
 
 // Fast SIMD implementation of CRC-32C for x86 with SSE 4.2
 uint32_t crc32c_hw(const uint8_t *data, size_t nbytes,
diff --git a/folly/Makefile.am b/folly/Makefile.am
index 6fe63d0b..ffc9aef0 100644
--- a/folly/Makefile.am
+++ b/folly/Makefile.am
@@ -310,6 +310,7 @@ libfollybase_la_SOURCES = \
 
 libfolly_la_SOURCES = \
 	Bits.cpp \
+	Checksum.cpp \
 	detail/CacheLocality.cpp \
 	dynamic.cpp \
 	File.cpp \