IR Cleanup, resolve ID objects through array subscripts

...instead of a special MEMBER type. This allows removing the
type member from V4IR::Member altogether (and thus unshadow from
V4IR::Expr::type). By not requiring the base of a id lookup
member expression to be a NAME, we can also speed up repeated
id lookups by fetching the id object array wrapper only once
per function.

Change-Id: I3e9b8f498d32ace4a0cc2254f49e02ecc124f79c
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

12 files changed, 34 insertions, 65 deletions

diff --git a/src/qml/compiler/qqmlcodegenerator.cpp b/src/qml/compiler/qqmlcodegenerator.cpp
index 4e1d2ef9c8..b38e2670e6 100644
--- a/src/qml/compiler/qqmlcodegenerator.cpp
+++ b/src/qml/compiler/qqmlcodegenerator.cpp
@@ -1213,6 +1213,7 @@ JSCodeGen::JSCodeGen(QQmlEnginePrivate *enginePrivate, const QString &fileName,
     , _contextObjectTemp(-1)
     , _scopeObjectTemp(-1)
     , _importedScriptsTemp(-1)
+    , _idArrayTemp(-1)
 {
     _module = jsModule;
     _module->setFileName(fileName);
@@ -1372,6 +1373,7 @@ void JSCodeGen::beginFunctionBodyHook()
     _contextObjectTemp = _block->newTemp();
     _scopeObjectTemp = _block->newTemp();
     _importedScriptsTemp = _block->newTemp();
+    _idArrayTemp = _block->newTemp();
 
     V4IR::Temp *temp = _block->TEMP(_contextObjectTemp);
     initMetaObjectResolver(&temp->memberResolver, _contextObject);
@@ -1382,6 +1384,7 @@ void JSCodeGen::beginFunctionBodyHook()
     move(temp, _block->NAME(V4IR::Name::builtin_qml_scope_object, 0, 0));
 
     move(_block->TEMP(_importedScriptsTemp), _block->NAME(V4IR::Name::builtin_qml_imported_scripts_object, 0, 0));
+    move(_block->TEMP(_idArrayTemp), _block->NAME(V4IR::Name::builtin_qml_id_array, 0, 0));
 }
 
 V4IR::Expr *JSCodeGen::fallbackNameLookup(const QString &name, int line, int col)
@@ -1403,8 +1406,13 @@ V4IR::Expr *JSCodeGen::fallbackNameLookup(const QString &name, int line, int col
     foreach (const IdMapping &mapping, _idObjects)
         if (name == mapping.name) {
             _function->idObjectDependencies.insert(mapping.idIndex);
-            return _block->QML_CONTEXT_MEMBER(_block->NAME(V4IR::Name::builtin_qml_id_scope, line, col),
-                                              _function->newString(mapping.name), mapping.idIndex);
+            V4IR::Expr *s = subscript(_block->TEMP(_idArrayTemp), _block->CONST(V4IR::SInt32Type, mapping.idIndex));
+            V4IR::Temp *result = _block->TEMP(_block->newTemp());
+            initMetaObjectResolver(&result->memberResolver, mapping.type);
+            _block->MOVE(result, s);
+            result = _block->TEMP(result->index);
+            result->isReadOnly = true; // don't allow use as lvalue
+            return result;
         }
 
     {
diff --git a/src/qml/compiler/qqmlcodegenerator_p.h b/src/qml/compiler/qqmlcodegenerator_p.h
index 4f80a7f148..636f2827bb 100644
--- a/src/qml/compiler/qqmlcodegenerator_p.h
+++ b/src/qml/compiler/qqmlcodegenerator_p.h
@@ -381,7 +381,7 @@ private:
     int _contextObjectTemp;
     int _scopeObjectTemp;
     int _importedScriptsTemp;
-    int _idScopeTemp;
+    int _idArrayTemp;
 };
 
 } // namespace QtQml
diff --git a/src/qml/compiler/qv4instr_moth_p.h b/src/qml/compiler/qv4instr_moth_p.h
index a2b8c870a5..5c92439f0c 100644
--- a/src/qml/compiler/qv4instr_moth_p.h
+++ b/src/qml/compiler/qv4instr_moth_p.h
@@ -126,7 +126,7 @@ QT_BEGIN_NAMESPACE
     F(MulNumberParams, mulNumberParams) \
     F(SubNumberParams, subNumberParams) \
     F(LoadThis, loadThis) \
-    F(LoadQmlIdObject, loadQmlIdObject) \
+    F(LoadQmlIdArray, loadQmlIdArray) \
     F(LoadQmlImportedScripts, loadQmlImportedScripts) \
     F(LoadQmlContextObject, loadQmlContextObject) \
     F(LoadQmlScopeObject, loadQmlScopeObject)
@@ -654,10 +654,9 @@ union Instr
         MOTH_INSTR_HEADER
         Param result;
     };
-    struct instr_loadQmlIdObject {
+    struct instr_loadQmlIdArray {
         MOTH_INSTR_HEADER
         Param result;
-        int id;
     };
     struct instr_loadQmlImportedScripts {
         MOTH_INSTR_HEADER
@@ -749,7 +748,7 @@ union Instr
     instr_mulNumberParams mulNumberParams;
     instr_subNumberParams subNumberParams;
     instr_loadThis loadThis;
-    instr_loadQmlIdObject loadQmlIdObject;
+    instr_loadQmlIdArray loadQmlIdArray;
     instr_loadQmlImportedScripts loadQmlImportedScripts;
     instr_loadQmlContextObject loadQmlContextObject;
     instr_loadQmlScopeObject loadQmlScopeObject;
diff --git a/src/qml/compiler/qv4isel_masm.cpp b/src/qml/compiler/qv4isel_masm.cpp
index 6f8bf13bd7..0854dd55ab 100644
--- a/src/qml/compiler/qv4isel_masm.cpp
+++ b/src/qml/compiler/qv4isel_masm.cpp
@@ -880,9 +880,9 @@ void InstructionSelection::loadThisObject(V4IR::Temp *temp)
 #endif
 }
 
-void InstructionSelection::loadQmlIdObject(int id, V4IR::Temp *temp)
+void InstructionSelection::loadQmlIdArray(V4IR::Temp *temp)
 {
-    generateFunctionCall(temp, __qmljs_get_id_object, Assembler::ContextRegister, Assembler::TrustedImm32(id));
+    generateFunctionCall(temp, __qmljs_get_id_array, Assembler::ContextRegister);
 }
 
 void InstructionSelection::loadQmlImportedScripts(V4IR::Temp *temp)
diff --git a/src/qml/compiler/qv4isel_masm_p.h b/src/qml/compiler/qv4isel_masm_p.h
index 0c2c994e32..5a02b62a73 100644
--- a/src/qml/compiler/qv4isel_masm_p.h
+++ b/src/qml/compiler/qv4isel_masm_p.h
@@ -1457,7 +1457,7 @@ protected:
     virtual void callSubscript(V4IR::Expr *base, V4IR::Expr *index, V4IR::ExprList *args, V4IR::Temp *result);
     virtual void convertType(V4IR::Temp *source, V4IR::Temp *target);
     virtual void loadThisObject(V4IR::Temp *temp);
-    virtual void loadQmlIdObject(int id, V4IR::Temp *temp);
+    virtual void loadQmlIdArray(V4IR::Temp *temp);
     virtual void loadQmlImportedScripts(V4IR::Temp *temp);
     virtual void loadQmlContextObject(V4IR::Temp *temp);
     virtual void loadQmlScopeObject(V4IR::Temp *temp);
diff --git a/src/qml/compiler/qv4isel_moth.cpp b/src/qml/compiler/qv4isel_moth.cpp
index 1b973b2359..c76c236de4 100644
--- a/src/qml/compiler/qv4isel_moth.cpp
+++ b/src/qml/compiler/qv4isel_moth.cpp
@@ -388,11 +388,10 @@ void InstructionSelection::loadThisObject(V4IR::Temp *temp)
     addInstruction(load);
 }
 
-void InstructionSelection::loadQmlIdObject(int id, V4IR::Temp *temp)
+void InstructionSelection::loadQmlIdArray(V4IR::Temp *temp)
 {
-    Instruction::LoadQmlIdObject load;
+    Instruction::LoadQmlIdArray load;
     load.result = getResultParam(temp);
-    load.id = id;
     addInstruction(load);
 }
 
diff --git a/src/qml/compiler/qv4isel_moth_p.h b/src/qml/compiler/qv4isel_moth_p.h
index ef26ba875d..bde7997c33 100644
--- a/src/qml/compiler/qv4isel_moth_p.h
+++ b/src/qml/compiler/qv4isel_moth_p.h
@@ -112,7 +112,7 @@ protected:
     virtual void constructProperty(V4IR::Temp *base, const QString &name, V4IR::ExprList *args, V4IR::Temp *result);
     virtual void constructValue(V4IR::Temp *value, V4IR::ExprList *args, V4IR::Temp *result);
     virtual void loadThisObject(V4IR::Temp *temp);
-    virtual void loadQmlIdObject(int id, V4IR::Temp *temp);
+    virtual void loadQmlIdArray(V4IR::Temp *temp);
     virtual void loadQmlImportedScripts(V4IR::Temp *temp);
     virtual void loadQmlContextObject(V4IR::Temp *temp);
     virtual void loadQmlScopeObject(V4IR::Temp *temp);
diff --git a/src/qml/compiler/qv4isel_p.cpp b/src/qml/compiler/qv4isel_p.cpp
index b3407867b4..a14a11c43e 100644
--- a/src/qml/compiler/qv4isel_p.cpp
+++ b/src/qml/compiler/qv4isel_p.cpp
@@ -103,6 +103,8 @@ void IRDecoder::visitMove(V4IR::Move *s)
         if (V4IR::Name *n = s->source->asName()) {
             if (n->id && *n->id == QStringLiteral("this")) // TODO: `this' should be a builtin.
                 loadThisObject(t);
+            else if (n->builtin == V4IR::Name::builtin_qml_id_array)
+                loadQmlIdArray(t);
             else if (n->builtin == V4IR::Name::builtin_qml_context_object)
                 loadQmlContextObject(t);
             else if (n->builtin == V4IR::Name::builtin_qml_scope_object)
@@ -142,15 +144,7 @@ void IRDecoder::visitMove(V4IR::Move *s)
                 return;
             }
         } else if (V4IR::Member *m = s->source->asMember()) {
-            if (m->type == V4IR::Member::MemberOfQmlContext) {
-                V4IR::Name *base = m->base->asName();
-                Q_ASSERT(base);
-
-                if (base->builtin == V4IR::Name::builtin_qml_id_scope) {
-                    loadQmlIdObject(m->memberIndex, t);
-                    return;
-                }
-            } else if (m->property) {
+            if (m->property) {
                 bool captureRequired = true;
                 if (_function) {
                     captureRequired = !_function->contextObjectDependencies.contains(m->property)
diff --git a/src/qml/compiler/qv4isel_p.h b/src/qml/compiler/qv4isel_p.h
index 647d85996d..6671ac1426 100644
--- a/src/qml/compiler/qv4isel_p.h
+++ b/src/qml/compiler/qv4isel_p.h
@@ -144,7 +144,7 @@ public: // to implement by subclasses:
     virtual void constructProperty(V4IR::Temp *base, const QString &name, V4IR::ExprList *args, V4IR::Temp *result) = 0;
     virtual void constructValue(V4IR::Temp *value, V4IR::ExprList *args, V4IR::Temp *result) = 0;
     virtual void loadThisObject(V4IR::Temp *temp) = 0;
-    virtual void loadQmlIdObject(int id, V4IR::Temp *temp) = 0;
+    virtual void loadQmlIdArray(V4IR::Temp *temp) = 0;
     virtual void loadQmlImportedScripts(V4IR::Temp *temp) = 0;
     virtual void loadQmlContextObject(V4IR::Temp *temp) = 0;
     virtual void loadQmlScopeObject(V4IR::Temp *temp) = 0;
diff --git a/src/qml/compiler/qv4jsir.cpp b/src/qml/compiler/qv4jsir.cpp
index 949a73432d..79b963f400 100644
--- a/src/qml/compiler/qv4jsir.cpp
+++ b/src/qml/compiler/qv4jsir.cpp
@@ -433,8 +433,8 @@ static const char *builtin_to_string(Name::Builtin b)
         return "builtin_setup_argument_object";
     case V4IR::Name::builtin_convert_this_to_object:
         return "builtin_convert_this_to_object";
-    case V4IR::Name::builtin_qml_id_scope:
-        return "builtin_qml_id_scope";
+    case V4IR::Name::builtin_qml_id_array:
+        return "builtin_qml_id_array";
     case V4IR::Name::builtin_qml_imported_scripts_object:
         return "builtin_qml_imported_scripts_object";
     case V4IR::Name::builtin_qml_scope_object:
@@ -841,13 +841,6 @@ Expr *BasicBlock::MEMBER(Expr *base, const QString *name, QQmlPropertyData *prop
     return e;
 }
 
-Expr *BasicBlock::QML_CONTEXT_MEMBER(Expr *base, const QString *id, int memberIndex)
-{
-    Member*e = function->New<Member>();
-    e->initQmlContextMember(base, id, memberIndex);
-    return e;
-}
-
 Stmt *BasicBlock::EXP(Expr *expr)
 { 
     if (isTerminated())
@@ -1034,12 +1027,7 @@ void CloneExpr::visitSubscript(Subscript *e)
 
 void CloneExpr::visitMember(Member *e)
 {
-    if (e->type == Member::MemberByName)
-        cloned = block->MEMBER(clone(e->base), e->name, e->property);
-    else if (e->type == Member::MemberOfQmlContext)
-        cloned = block->QML_CONTEXT_MEMBER(clone(e->base), e->name, e->memberIndex);
-    else
-        Q_ASSERT(!"Unimplemented!");
+    cloned = block->MEMBER(clone(e->base), e->name, e->property);
 }
 
 } // end of namespace IR
diff --git a/src/qml/compiler/qv4jsir_p.h b/src/qml/compiler/qv4jsir_p.h
index 5fd58acba4..fd54460b5c 100644
--- a/src/qml/compiler/qv4jsir_p.h
+++ b/src/qml/compiler/qv4jsir_p.h
@@ -343,7 +343,7 @@ struct Name: Expr {
         builtin_define_object_literal,
         builtin_setup_argument_object,
         builtin_convert_this_to_object,
-        builtin_qml_id_scope,
+        builtin_qml_id_array,
         builtin_qml_imported_scripts_object,
         builtin_qml_context_object,
         builtin_qml_scope_object
@@ -378,9 +378,10 @@ struct Temp: Expr {
     };
 
     unsigned index;
-    unsigned scope : 28; // how many scopes outside the current one?
+    unsigned scope : 27; // how many scopes outside the current one?
     unsigned kind  : 3;
     unsigned isArgumentsOrEval : 1;
+    unsigned isReadOnly : 1;
     // Used when temp is used as base in member expression
     MemberExpressionResolver memberResolver;
 
@@ -394,10 +395,11 @@ struct Temp: Expr {
         this->index = index;
         this->scope = scope;
         this->isArgumentsOrEval = false;
+        this->isReadOnly = false;
     }
 
     virtual void accept(ExprVisitor *v) { v->visitTemp(this); }
-    virtual bool isLValue() { return true; }
+    virtual bool isLValue() { return !isReadOnly; }
     virtual Temp *asTemp() { return this; }
 
     virtual void dump(QTextStream &out) const;
@@ -538,38 +540,19 @@ struct Subscript: Expr {
 };
 
 struct Member: Expr {
-    enum MemberType {
-        MemberByName,
-        // QML extensions
-        MemberOfQmlContext // lookup in context's id values
-    };
-
-    MemberType type;
     Expr *base;
     const QString *name;
-    int memberIndex; // used if type == MemberOfQmlContext
     QQmlPropertyData *property;
 
     void init(Expr *base, const QString *name, QQmlPropertyData *property = 0)
     {
-        this->type = MemberByName;
         this->base = base;
         this->name = name;
-        this->memberIndex = -1;
         this->property = property;
     }
 
-    void initQmlContextMember(Expr *base, const QString *name, int memberIndex)
-    {
-        this->type = MemberOfQmlContext;
-        this->base = base;
-        this->name = name;
-        this->memberIndex = memberIndex;
-        this->property = 0;
-    }
-
     virtual void accept(ExprVisitor *v) { v->visitMember(this); }
-    virtual bool isLValue() { return type != MemberOfQmlContext; }
+    virtual bool isLValue() { return true; }
     virtual Member *asMember() { return this; }
 
     virtual void dump(QTextStream &out) const;
@@ -872,7 +855,6 @@ struct BasicBlock {
     Expr *NEW(Expr *base, ExprList *args = 0);
     Expr *SUBSCRIPT(Expr *base, Expr *index);
     Expr *MEMBER(Expr *base, const QString *name, QQmlPropertyData *property = 0);
-    Expr *QML_CONTEXT_MEMBER(Expr *base, const QString *id, int memberIndex);
 
     Stmt *EXP(Expr *expr);
 
diff --git a/src/qml/compiler/qv4regalloc.cpp b/src/qml/compiler/qv4regalloc.cpp
index a0245c6808..a1594da82e 100644
--- a/src/qml/compiler/qv4regalloc.cpp
+++ b/src/qml/compiler/qv4regalloc.cpp
@@ -338,9 +338,8 @@ protected: // IRDecoder
         addDef(temp);
     }
 
-    virtual void loadQmlIdObject(int id, V4IR::Temp *temp)
+    virtual void loadQmlIdArray(V4IR::Temp *temp)
     {
-        Q_UNUSED(id);
         addDef(temp);
         addCall();
     }