V4: Get rid of Reference::This and treat it as a stack slot

This actually generates better code, for example for 'this.x'.

Previously:
    LoadReg (this)
    GetLookupA acc(0)

Now:
    GetLookup (this)(0)

Change-Id: I7e4125d3dff707e9af9691f8b00c5c398087e395
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

2 files changed, 2 insertions, 14 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index 3cee80e977..04d16d412e 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -3073,8 +3073,6 @@ Codegen::Reference &Codegen::Reference::operator =(const Reference &other)
         qmlNotifyIndex = other.qmlNotifyIndex;
         captureRequired = other.captureRequired;
         break;
-    case This:
-        break;
     }
 
     // keep loaded reference
@@ -3111,8 +3109,6 @@ bool Codegen::Reference::operator==(const Codegen::Reference &other) const
     case QmlContextObject:
         return qmlCoreIndex == other.qmlCoreIndex && qmlNotifyIndex == other.qmlNotifyIndex
                 && captureRequired == other.captureRequired;
-    case This:
-        return true;
     }
     return true;
 }
@@ -3218,7 +3214,6 @@ bool Codegen::Reference::storeWipesAccumulator() const
     switch (type) {
     default:
     case Invalid:
-    case This:
     case Const:
     case Accumulator:
         Q_UNREACHABLE();
@@ -3303,7 +3298,6 @@ void Codegen::Reference::storeAccumulator() const
     case Invalid:
     case Accumulator:
     case Const:
-    case This:
         break;
     }
 
@@ -3457,11 +3451,6 @@ QT_WARNING_POP
         if (!captureRequired)
             codegen->_context->contextObjectPropertyDependencies.insert(qmlCoreIndex, qmlNotifyIndex);
     } return;
-    case This: {
-        Instruction::LoadReg load;
-        load.reg = Moth::StackSlot::createRegister(CallData::This);
-        codegen->bytecodeGenerator->addInstruction(load);
-    } return;
     case Invalid:
         break;
     }
diff --git a/src/qml/compiler/qv4codegen_p.h b/src/qml/compiler/qv4codegen_p.h
index 89c887d46d..dba9388292 100644
--- a/src/qml/compiler/qv4codegen_p.h
+++ b/src/qml/compiler/qv4codegen_p.h
@@ -184,8 +184,7 @@ public:
             QmlScopeObject,
             QmlContextObject,
             LastLValue = QmlContextObject,
-            Const,
-            This
+            Const
         } type = Invalid;
 
         bool isLValue() const { return !isReadonly; }
@@ -284,7 +283,7 @@ public:
             return r;
         }
         static Reference fromThis(Codegen *cg) {
-            Reference r(cg, This);
+            Reference r = fromStackSlot(cg, CallData::This);
             r.isReadonly = true;
             return r;
         }