Get rid of the GCBlocker

It's a hack we needed when we still had a conservative GC, but
it is not required anymore. The only thing we still need is the
protection against running the GC recursively.

Change-Id: I55cd51d4929c828db5b61b38e781467c5bf77314
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

src/qml/jsruntime/qv4engine.cpp

@@ -158,8 +158,6 @@ ExecutionEngine::ExecutionEngine(EvalISelFactory *factory)
     }
     Q_ASSERT(maxCallDepth > 0);
 
-    MemoryManager::GCBlocker gcBlocker(memoryManager);
-
     if (!factory) {
 #if QT_CONFIG(qml_interpreter)
         bool jitDisabled = true;

src/qml/jsruntime/qv4script.cpp

@@ -88,8 +88,6 @@ void Script::parse()
     ExecutionEngine *v4 = scope->engine();
     Scope valueScope(v4);
 
-    MemoryManager::GCBlocker gcBlocker(v4->memoryManager);
-
     IR::Module module(v4->debugger() != 0);
 
     QQmlJS::Engine ee, *engine = ⅇ

src/qml/memory/qv4mm.cpp

@@ -565,16 +565,6 @@ void MemoryManager::sweep(bool lastSweep)
     }
 }
 
-bool MemoryManager::isGCBlocked() const
-{
-    return m_d->gcBlocked;
-}
-
-void MemoryManager::setGCBlocked(bool blockGC)
-{
-    m_d->gcBlocked = blockGC;
-}
-
 void MemoryManager::runGC()
 {
     if (m_d->gcBlocked) {

src/qml/memory/qv4mm_p.h

@@ -76,26 +76,6 @@ class Q_QML_EXPORT MemoryManager
 public:
     struct Data;
 
-    class GCBlocker
-    {
-    public:
-        GCBlocker(MemoryManager *mm)
-            : mm(mm)
-            , wasBlocked(mm->isGCBlocked())
-        {
-            mm->setGCBlocked(true);
-        }
-
-        ~GCBlocker()
-        {
-            mm->setGCBlocked(wasBlocked);
-        }
-
-    private:
-        MemoryManager *mm;
-        bool wasBlocked;
-    };
-
 public:
     MemoryManager(ExecutionEngine *engine);
     ~MemoryManager();
@@ -309,8 +289,6 @@ public:
         return t->d();
     }
 
-    bool isGCBlocked() const;
-    void setGCBlocked(bool blockGC);
     void runGC();
 
     void dumpStats() const;