From d2cd4b666747ee4338532555a6f05def10a14d63 Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gunnar.beutner@netways.de>
Date: Tue, 19 Apr 2016 09:37:41 +0200
Subject: [PATCH] Improve performance for locks and value conversions

refs #11612
---
 lib/base/i2-base.hpp    | 9 +++++++++
 lib/base/object.hpp     | 2 +-
 lib/base/objectlock.hpp | 8 ++++----
 lib/base/value.hpp      | 2 +-
 lib/config/vmops.hpp    | 4 ++--
 5 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/lib/base/i2-base.hpp b/lib/base/i2-base.hpp
index 1c46815a1..3d3b67395 100644
--- a/lib/base/i2-base.hpp
+++ b/lib/base/i2-base.hpp
@@ -91,4 +91,13 @@
 #	define I2_BASE_API I2_IMPORT
 #endif /* I2_BASE_BUILD */
 
+#if defined(__GNUC__)
+#	define likely(x) __builtin_expect(!!(x), 1)
+#	define unlikely(x) __builtin_expect(!!(x), 0)
+#else
+#	define likely(x) (x)
+#	define unlikely(x) (x)
+#endif
+
+
 #endif /* I2BASE_H */
diff --git a/lib/base/object.hpp b/lib/base/object.hpp
index 654e56950..c454bdc12 100644
--- a/lib/base/object.hpp
+++ b/lib/base/object.hpp
@@ -191,7 +191,7 @@ inline void intrusive_ptr_release(Object *object)
 	refs = __sync_sub_and_fetch(&object->m_References, 1);
 #endif /* _WIN32 */
 
-	if (refs == 0) {
+	if (unlikely(refs == 0)) {
 #ifdef I2_LEAK_DEBUG
 		TypeRemoveObject(object);
 #endif /* I2_LEAK_DEBUG */
diff --git a/lib/base/objectlock.hpp b/lib/base/objectlock.hpp
index ea2e05484..9368a25bc 100644
--- a/lib/base/objectlock.hpp
+++ b/lib/base/objectlock.hpp
@@ -62,14 +62,14 @@ public:
 
 #ifdef _WIN32
 #	ifdef _WIN64
-		while (InterlockedCompareExchange64((LONGLONG *)&object->m_Mutex, I2MUTEX_LOCKED, I2MUTEX_UNLOCKED) != I2MUTEX_UNLOCKED) {
+		while (likely(InterlockedCompareExchange64((LONGLONG *)&object->m_Mutex, I2MUTEX_LOCKED, I2MUTEX_UNLOCKED) != I2MUTEX_UNLOCKED)) {
 #	else /* _WIN64 */
-		while (InterlockedCompareExchange(&object->m_Mutex, I2MUTEX_LOCKED, I2MUTEX_UNLOCKED) != I2MUTEX_UNLOCKED) {
+		while (likely(InterlockedCompareExchange(&object->m_Mutex, I2MUTEX_LOCKED, I2MUTEX_UNLOCKED) != I2MUTEX_UNLOCKED)) {
 #	endif /* _WIN64 */
 #else /* _WIN32 */
-		while (!__sync_bool_compare_and_swap(&object->m_Mutex, I2MUTEX_UNLOCKED, I2MUTEX_LOCKED)) {
+		while (likely(!__sync_bool_compare_and_swap(&object->m_Mutex, I2MUTEX_UNLOCKED, I2MUTEX_LOCKED))) {
 #endif /* _WIN32 */
-			if (object->m_Mutex > I2MUTEX_LOCKED) {
+			if (likely(object->m_Mutex > I2MUTEX_LOCKED)) {
 				boost::recursive_mutex *mtx = reinterpret_cast<boost::recursive_mutex *>(object->m_Mutex);
 				mtx->lock();
 
diff --git a/lib/base/value.hpp b/lib/base/value.hpp
index df904ce22..34fe7cbd6 100644
--- a/lib/base/value.hpp
+++ b/lib/base/value.hpp
@@ -148,7 +148,7 @@ public:
 		if (!IsObject())
 			BOOST_THROW_EXCEPTION(std::runtime_error("Cannot convert value of type '" + GetTypeName() + "' to an object."));
 
-		Object::Ptr object = boost::get<Object::Ptr>(m_Value);
+		const Object::Ptr& object = boost::get<Object::Ptr>(m_Value);
 
 		ASSERT(object);
 
diff --git a/lib/config/vmops.hpp b/lib/config/vmops.hpp
index c330b6cd8..1479da91f 100644
--- a/lib/config/vmops.hpp
+++ b/lib/config/vmops.hpp
@@ -193,10 +193,10 @@ public:
 
 	static inline Value GetField(const Value& context, const String& field, bool sandboxed = false, const DebugInfo& debugInfo = DebugInfo())
 	{
-		if (context.IsEmpty() && !context.IsString())
+		if (unlikely(context.IsEmpty() && !context.IsString()))
 			return Empty;
 
-		if (!context.IsObject())
+		if (unlikely(!context.IsObject()))
 			return GetPrototypeField(context, field, true, debugInfo);
 
 		Object::Ptr object = context;