From 37d40eed8324114070253f762dc3545bc938cb1e Mon Sep 17 00:00:00 2001
From: Yedidya Feldblum <yfeldblum@fb.com>
Date: Fri, 2 Oct 2015 23:08:39 -0700
Subject: [PATCH] Fix Build: folly/Range.h for build platforms missing SSE42
 headers

Summary: [Folly] Fix Build: `folly/Range.h` for build platforms missing SSE42 headers.

We make the assumption that if the compiler defines the appropriate symbols indicating SSE42, that the corresponding intrinsics headers are available.

We also remove `Range.cpp` from `Makefile.am`, which we forgot to do in the blamed diff.

Reviewed By: @nbronson

Differential Revision: D2504934
---
 folly/Makefile.am           |  1 -
 folly/Portability.h         |  3 +++
 folly/detail/RangeSse42.cpp | 42 +++++++++++++++++++++++++++++++++++--
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/folly/Makefile.am b/folly/Makefile.am
index 8301005f..5f4eef08 100644
--- a/folly/Makefile.am
+++ b/folly/Makefile.am
@@ -309,7 +309,6 @@ libfollybase_la_SOURCES = \
 	Format.cpp \
 	FormatTables.cpp \
 	Malloc.cpp \
-	Range.cpp \
 	RangeCommon.cpp \
 	RangeSse42.cpp \
 	StringBase.cpp \
diff --git a/folly/Portability.h b/folly/Portability.h
index 7ccedfac..ca8c28a3 100644
--- a/folly/Portability.h
+++ b/folly/Portability.h
@@ -300,6 +300,9 @@ typedef SSIZE_T ssize_t;
 # endif
 #endif
 
+#define FOLLY_SSE_PREREQ(major, minor) \
+  (FOLLY_SSE > major || FOLLY_SSE == major && FOLLY_SSE_MINOR >= minor)
+
 #if FOLLY_UNUSUAL_GFLAGS_NAMESPACE
 namespace FOLLY_GFLAGS_NAMESPACE { }
 namespace gflags {
diff --git a/folly/detail/RangeSse42.cpp b/folly/detail/RangeSse42.cpp
index 1d1d32db..c5409887 100644
--- a/folly/detail/RangeSse42.cpp
+++ b/folly/detail/RangeSse42.cpp
@@ -14,16 +14,50 @@
  * limitations under the License.
  */
 
+
+
 #include "RangeSse42.h"
 
+#include <glog/logging.h>
+#include <folly/Portability.h>
+
+
+
+//  Essentially, two versions of this file: one with an SSE42 implementation
+//  and one with a fallback implementation. We determine which version to use by
+//  testing for the presence of the required headers.
+//
+//  TODO: Maybe this should be done by the build system....
+#if !FOLLY_SSE_PREREQ(4, 2)
+
+
+
+namespace folly {
+
+namespace detail {
+
+size_t qfind_first_byte_of_sse42(const StringPieceLite haystack,
+                                 const StringPieceLite needles) {
+  CHECK(false) << "Function " << __func__ << " only works with SSE42!";
+  return qfind_first_byte_of_nosse(haystack, needles);
+}
+
+}
+
+}
+
+
+
+# else
+
+
+
 #include <cstdint>
 #include <limits>
 #include <string>
 #include <emmintrin.h>
 #include <smmintrin.h>
-#include <glog/logging.h>
 #include <folly/Likely.h>
-#include <folly/Portability.h>
 
 namespace folly {
 
@@ -188,3 +222,7 @@ size_t qfind_first_byte_of_sse42(const StringPieceLite haystack,
 }
 
 }
+
+
+
+#endif
-- 
2.34.1