QtQml: Remove the rotten init/destroy call checking

QML_CHECK_INIT_DESTROY_CALLS was meant to catch heap objects being used
before init(), used after destroy(), destroyed twice, or never destroyed.
It has not compiled for a long time, and it's impossible to revive it
without large scale refactoring. We can't stash an extra field into
Heap::Base without changing the object layout quite a bit.

Since it has been unused for a long time, we don't even know if it works
correctly. Let's drop it.

Without the checking there is no difference between d() and d_unchecked()
anymore. Drop the latter.

Task-number: QTBUG-149512
Change-Id: Ic489d76177509c39536c23ff362c0026ac53d0f5
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

10 files changed, 14 insertions, 73 deletions

diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 5729d0e037..fbd75bf8d7 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -946,7 +946,7 @@ void ExecutionEngine::initRootContext()
 {
     Scope scope(this);
     Scoped<ExecutionContext> r(scope, memoryManager->allocManaged<ExecutionContext>());
-    r->d_unchecked()->init(Heap::ExecutionContext::Type_GlobalContext);
+    r->d()->init(Heap::ExecutionContext::Type_GlobalContext);
     r->d()->activation.set(this, globalObject->d());
     jsObjects[RootContext] = r;
     jsObjects[ScriptContext] = r;
diff --git a/src/qml/jsruntime/qv4managed_p.h b/src/qml/jsruntime/qv4managed_p.h
index ef0f922fa3..3bb5c45906 100644
--- a/src/qml/jsruntime/qv4managed_p.h
+++ b/src/qml/jsruntime/qv4managed_p.h
@@ -48,12 +48,7 @@ inline void qYouForgotTheQ_MANAGED_Macro(T1, T2) {}
         static const QV4::VTable static_vtbl; \
         static inline const QV4::VTable *staticVTable() { return &static_vtbl; } \
         V4_MANAGED_SIZE_TEST \
-        QV4::Heap::DataClass *d_unchecked() const { return static_cast<QV4::Heap::DataClass *>(m()); } \
-        QV4::Heap::DataClass *d() const { \
-            QV4::Heap::DataClass *dptr = d_unchecked(); \
-            dptr->_checkIsInitialized(); \
-            return dptr; \
-        }
+        QV4::Heap::DataClass *d() const { return static_cast<QV4::Heap::DataClass *>(m()); }
 
 #define V4_MANAGED(DataClass, superClass) \
     private: \
diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index adcca8b92c..4be9adedd3 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -2887,7 +2887,7 @@ ReturnedValue QmlSignalHandler::call(const Value *thisObject, const Value *argv,
 
 void QmlSignalHandler::initProto(ExecutionEngine *engine)
 {
-    if (engine->signalHandlerPrototype()->d_unchecked())
+    if (engine->signalHandlerPrototype()->d())
         return;
 
     Scope scope(engine);
diff --git a/src/qml/jsruntime/qv4string_p.h b/src/qml/jsruntime/qv4string_p.h
index 828e5664f0..d144a623ac 100644
--- a/src/qml/jsruntime/qv4string_p.h
+++ b/src/qml/jsruntime/qv4string_p.h
@@ -246,12 +246,7 @@ public:
 
 struct ComplexString : String {
     typedef QV4::Heap::ComplexString Data;
-    QV4::Heap::ComplexString *d_unchecked() const { return static_cast<QV4::Heap::ComplexString *>(m()); }
-    QV4::Heap::ComplexString *d() const {
-        QV4::Heap::ComplexString *dptr = d_unchecked();
-        dptr->_checkIsInitialized();
-        return dptr;
-    }
+    QV4::Heap::ComplexString *d() const { return static_cast<QV4::Heap::ComplexString *>(m()); }
 };
 
 inline
diff --git a/src/qml/jsruntime/qv4vtable_p.h b/src/qml/jsruntime/qv4vtable_p.h
index b8bae7ba72..ea0dd33992 100644
--- a/src/qml/jsruntime/qv4vtable_p.h
+++ b/src/qml/jsruntime/qv4vtable_p.h
@@ -271,12 +271,7 @@ const QV4::VTable classname::static_vtbl = DEFINE_MANAGED_VTABLE_INT(classname,
         static const QV4::VTable static_vtbl; \
         static inline const QV4::VTable *staticVTable() { return &static_vtbl; } \
         V4_MANAGED_SIZE_TEST \
-        QV4::Heap::DataClass *d_unchecked() const { return static_cast<QV4::Heap::DataClass *>(m()); } \
-        QV4::Heap::DataClass *d() const { \
-            QV4::Heap::DataClass *dptr = d_unchecked(); \
-            dptr->_checkIsInitialized(); \
-            return dptr; \
-        } \
+        QV4::Heap::DataClass *d() const { return static_cast<QV4::Heap::DataClass *>(m()); } \
         static_assert(std::is_trivially_copyable_v<QV4::Heap::DataClass>); \
         static_assert(std::is_trivially_default_constructible_v<QV4::Heap::DataClass>);
 
diff --git a/src/qml/memory/qv4heap_p.h b/src/qml/memory/qv4heap_p.h
index 46b53c1cea..c888ffca2e 100644
--- a/src/qml/memory/qv4heap_p.h
+++ b/src/qml/memory/qv4heap_p.h
@@ -21,10 +21,6 @@
 #include <private/qv4vtable_p.h>
 #include <QtCore/QSharedPointer>
 
-// To check if Heap::Base::init is called (meaning, all subclasses did their init and called their
-// parent's init all up the inheritance chain), define QML_CHECK_INIT_DESTROY_CALLS below.
-#undef QML_CHECK_INIT_DESTROY_CALLS
-
 QT_BEGIN_NAMESPACE
 
 namespace QV4 {
@@ -91,42 +87,8 @@ struct Q_QML_EXPORT Base {
     void *operator new(size_t, Base *m) { return m; }
     void operator delete(void *, Base *) {}
 
-    void init() { _setInitialized(); }
-    void destroy() { _setDestroyed(); }
-#ifdef QML_CHECK_INIT_DESTROY_CALLS
-    enum { Uninitialized = 0, Initialized, Destroyed } _livenessStatus;
-    void _checkIsInitialized() {
-        if (_livenessStatus == Uninitialized)
-            fprintf(stderr, "ERROR: use of object '%s' before call to init() !!\n",
-                    vtable()->className);
-        else if (_livenessStatus == Destroyed)
-            fprintf(stderr, "ERROR: use of object '%s' after call to destroy() !!\n",
-                    vtable()->className);
-        Q_ASSERT(_livenessStatus == Initialized);
-    }
-    void _checkIsDestroyed() {
-        if (_livenessStatus == Initialized)
-            fprintf(stderr, "ERROR: object '%s' was never destroyed completely !!\n",
-                    vtable()->className);
-        Q_ASSERT(_livenessStatus == Destroyed);
-    }
-    void _setInitialized() { Q_ASSERT(_livenessStatus == Uninitialized); _livenessStatus = Initialized; }
-    void _setDestroyed() {
-        if (_livenessStatus == Uninitialized)
-            fprintf(stderr, "ERROR: attempting to destroy an uninitialized object '%s' !!\n",
-                    vtable()->className);
-        else if (_livenessStatus == Destroyed)
-            fprintf(stderr, "ERROR: attempting to destroy repeatedly object '%s' !!\n",
-                    vtable()->className);
-        Q_ASSERT(_livenessStatus == Initialized);
-        _livenessStatus = Destroyed;
-    }
-#else
-    Q_ALWAYS_INLINE void _checkIsInitialized() {}
-    Q_ALWAYS_INLINE void _checkIsDestroyed() {}
-    Q_ALWAYS_INLINE void _setInitialized() {}
-    Q_ALWAYS_INLINE void _setDestroyed() {}
-#endif
+    void init() {}
+    void destroy() {}
 };
 static_assert(std::is_trivially_copyable_v<Base>);
 static_assert(std::is_trivially_default_constructible_v<Base>);
diff --git a/src/qml/memory/qv4mm.cpp b/src/qml/memory/qv4mm.cpp
index 31634ed0e0..84d2c2b79f 100644
--- a/src/qml/memory/qv4mm.cpp
+++ b/src/qml/memory/qv4mm.cpp
@@ -292,10 +292,8 @@ bool Chunk::sweep(ExecutionEngine *engine)
             const VTable *v = b->internalClass->vtable;
 //            if (Q_UNLIKELY(classCountPtr))
 //                classCountPtr(v->className);
-            if (v->destroy) {
+            if (v->destroy)
                 v->destroy(b);
-                b->_checkIsDestroyed();
-            }
 #ifdef V4_USE_HEAPTRACK
             heaptrack_report_free(itemToFree);
 #endif
@@ -338,10 +336,8 @@ void Chunk::freeAll(ExecutionEngine *engine)
 
             HeapItem *itemToFree = o + index;
             Heap::Base *b = *itemToFree;
-            if (b->internalClass->vtable->destroy) {
+            if (b->internalClass->vtable->destroy)
                 b->internalClass->vtable->destroy(b);
-                b->_checkIsDestroyed();
-            }
 #ifdef V4_USE_HEAPTRACK
             heaptrack_report_free(itemToFree);
 #endif
@@ -591,10 +587,8 @@ static void freeHugeChunk(ChunkAllocator *chunkAllocator, const HugeItemAllocato
     Heap::Base *b = *itemToFree;
     const VTable *v = b->internalClass->vtable;
 
-    if (v->destroy) {
+    if (v->destroy)
         v->destroy(b);
-        b->_checkIsDestroyed();
-    }
     if (c.segment) {
         // own memory segment
         c.segment->free(c.chunk, c.size);
diff --git a/src/qml/memory/qv4mm_p.h b/src/qml/memory/qv4mm_p.h
index 30ae40f12a..631138dec5 100644
--- a/src/qml/memory/qv4mm_p.h
+++ b/src/qml/memory/qv4mm_p.h
@@ -373,7 +373,7 @@ public:
     {
         Scope scope(engine);
         Scoped<ObjectType> t(scope, allocateObject<ObjectType>());
-        t->d_unchecked()->init(std::forward<Args>(args)...);
+        t->d()->init(std::forward<Args>(args)...);
         return t->d();
     }
 
@@ -382,7 +382,7 @@ public:
     {
         Scope scope(engine);
         Scoped<ManagedType> t(scope, allocManaged<ManagedType>());
-        t->d_unchecked()->init(std::forward<Args>(args)...);
+        t->d()->init(std::forward<Args>(args)...);
         return t->d();
     }
 
diff --git a/src/qml/qml/qqmltypewrapper.cpp b/src/qml/qml/qqmltypewrapper.cpp
index fea5cfb97a..1cdc7664b0 100644
--- a/src/qml/qml/qqmltypewrapper.cpp
+++ b/src/qml/qml/qqmltypewrapper.cpp
@@ -230,7 +230,7 @@ ReturnedValue QQmlTypeWrapper::method_toString(
 
 void QQmlTypeWrapper::initProto(ExecutionEngine *v4)
 {
-    if (v4->typeWrapperPrototype()->d_unchecked())
+    if (v4->typeWrapperPrototype()->d())
         return;
 
     Scope scope(v4);
diff --git a/src/qml/qml/qqmlvaluetypewrapper.cpp b/src/qml/qml/qqmlvaluetypewrapper.cpp
index 66a4606d3d..cffc2bfc22 100644
--- a/src/qml/qml/qqmlvaluetypewrapper.cpp
+++ b/src/qml/qml/qqmlvaluetypewrapper.cpp
@@ -118,7 +118,7 @@ ReturnedValue QQmlValueTypeWrapper::create(
 
 void QQmlValueTypeWrapper::initProto(ExecutionEngine *v4)
 {
-    if (v4->valueTypeWrapperPrototype()->d_unchecked())
+    if (v4->valueTypeWrapperPrototype()->d())
         return;
 
     Scope scope(v4);