outline HashingThreadId::get

Reviewed By: Mizuchi

Differential Revision: D27669414

fbshipit-source-id: 617e0b5f17fa8ce5505f7f16b00516ba7f21b064

folly/concurrency/CacheLocality.cpp

@@ -28,6 +28,8 @@
 #include <folly/Exception.h>
 #include <folly/FileUtil.h>
 #include <folly/ScopeGuard.h>
+#include <folly/hash/Hash.h>
+#include <folly/system/ThreadId.h>
 
 namespace folly {
 
@@ -327,6 +329,11 @@ unsigned SequentialThreadId::get() {
 }
 #endif
 
+/////////////// HashingThreadId
+unsigned HashingThreadId::get() {
+  return hash::twang_32from64(getCurrentThreadID());
+}
+
 namespace detail {
 
 int AccessSpreaderBase::degenerateGetcpu(unsigned* cpu, unsigned* node, void*) {

folly/concurrency/CacheLocality.h

@@ -32,10 +32,8 @@
 #include <folly/Likely.h>
 #include <folly/Memory.h>
 #include <folly/Portability.h>
-#include <folly/hash/Hash.h>
 #include <folly/lang/Align.h>
 #include <folly/lang/Exception.h>
-#include <folly/system/ThreadId.h>
 
 #if !FOLLY_MOBILE && defined(FOLLY_TLS)
 #define FOLLY_CL_USE_FOLLY_TLS 1
@@ -154,7 +152,7 @@ struct SequentialThreadId {
 #endif
 
 struct HashingThreadId {
-  static unsigned get() { return hash::twang_32from64(getCurrentThreadID()); }
+  static unsigned get();
 };
 
 /// A class that lazily binds a unique (for each implementation of Atom)