Smaller performance fixes

Move commonly used variables in the ExecutionEngine
to the beginning of the struct to increase cache locality.
Keep the engine pointer in a register in the interpreter to
save one memory load per instruction.

Change-Id: If2540c66b62685701511f410aff495c0a20ca694
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

3 files changed, 14 insertions, 12 deletions

diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 6768de27f1..4c1d3fceb2 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -157,10 +157,10 @@ quintptr getStackLimit()
 
 
 ExecutionEngine::ExecutionEngine(QQmlJS::EvalISelFactory *factory)
-    : memoryManager(new QV4::MemoryManager)
+    : current(0)
+    , memoryManager(new QV4::MemoryManager)
     , executableAllocator(new QV4::ExecutableAllocator)
     , regExpAllocator(new QV4::ExecutableAllocator)
-    , current(0)
     , bumperPointerAllocator(new WTF::BumpPointerAllocator)
     , jsStack(new WTF::PageAllocation)
     , debugger(0)
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index 8a7cd75a7b..6974835e8b 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -121,11 +121,6 @@ struct ExecutionContextSaver;
 
 struct Q_QML_EXPORT ExecutionEngine
 {
-    MemoryManager *memoryManager;
-    ExecutableAllocator *executableAllocator;
-    ExecutableAllocator *regExpAllocator;
-    QScopedPointer<QQmlJS::EvalISelFactory> iselFactory;
-
 private:
     friend struct ExecutionContextSaver;
     friend struct ExecutionContext;
@@ -133,9 +128,16 @@ private:
 public:
     ExecutionContext *currentContext() const { return current; }
 
+    Value *jsStackTop;
+    quint32 hasException;
     GlobalContext *rootContext;
 
-    Value *jsStackTop;
+    MemoryManager *memoryManager;
+    ExecutableAllocator *executableAllocator;
+    ExecutableAllocator *regExpAllocator;
+    QScopedPointer<QQmlJS::EvalISelFactory> iselFactory;
+
+
     Value *jsStackLimit;
     quintptr cStackLimit;
 
@@ -353,7 +355,6 @@ public:
 
     // Exception handling
     Value exceptionValue;
-    quint32 hasException;
     StackTrace exceptionStackTrace;
 
     ReturnedValue throwException(const ValueRef value);
diff --git a/src/qml/jsruntime/qv4vme_moth.cpp b/src/qml/jsruntime/qv4vme_moth.cpp
index 22fe4968a2..5f079a7d05 100644
--- a/src/qml/jsruntime/qv4vme_moth.cpp
+++ b/src/qml/jsruntime/qv4vme_moth.cpp
@@ -150,12 +150,12 @@ Param traceParam(const Param &param)
 
 #define STOREVALUE(param, value) { \
     QV4::ReturnedValue tmp = (value); \
-    if (context->engine->hasException) \
+    if (engine->hasException) \
         goto catchException; \
     VALUE(param) = tmp; \
     }
 #define CHECK_EXCEPTION \
-    if (context->engine->hasException) \
+    if (engine->hasException) \
         goto catchException
 
 QV4::ReturnedValue VME::run(QV4::ExecutionContext *context, const uchar *code,
@@ -183,7 +183,7 @@ QV4::ReturnedValue VME::run(QV4::ExecutionContext *context, const uchar *code,
 
     const uchar *exceptionHandler = 0;
 
-    QV4::Debugging::Debugger *debugger = context->engine->debugger;
+    QV4::ExecutionEngine *engine = context->engine;
 
 #ifdef DO_TRACE_INSTR
     qDebug("Starting VME with context=%p and code=%p", context, code);
@@ -658,6 +658,7 @@ QV4::ReturnedValue VME::run(QV4::ExecutionContext *context, const uchar *code,
     MOTH_END_INSTR(Ret)
 
     MOTH_BEGIN_INSTR(Debug)
+        QV4::Debugging::Debugger *debugger = context->engine->debugger;
         if (debugger && (instr.breakPoint || debugger->pauseAtNextOpportunity()))
             debugger->maybeBreakAtInstruction(code, instr.breakPoint);
     MOTH_END_INSTR(Debug)