garbage collect InternalClass

Internal classes are now allocated and collected through
the GC. As they are important to the deletion of other
objects (because of the vtable pointer living inside the
internal class), they need to get destroyed after regular
objects have been sweeped. Achieve this by using a separate
block allocator for internal class objects.

Our lookups do often contain pointers to internal classes,
so those need to be marked as well, so we don't accidentally
collect them.

Change-Id: I4762b054361c70c31f79f920f669ea0e8551601f
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 26 insertions, 10 deletions

diff --git a/src/qml/compiler/qv4compileddata.cpp b/src/qml/compiler/qv4compileddata.cpp
index a149d84646..005263e582 100644
--- a/src/qml/compiler/qv4compileddata.cpp
+++ b/src/qml/compiler/qv4compileddata.cpp
@@ -96,8 +96,9 @@ static QString cacheFilePath(const QUrl &url)
 #endif
 
 CompilationUnit::CompilationUnit(const Unit *unitData)
-    : data(unitData)
-{}
+{
+    data = unitData;
+}
 
 #ifndef V4_BOOTSTRAP
 CompilationUnit::~CompilationUnit()
@@ -157,15 +158,15 @@ QV4::Function *CompilationUnit::linkToEngine(ExecutionEngine *engine)
     }
 
     if (data->jsClassTableSize) {
-        runtimeClasses = (QV4::InternalClass**)malloc(data->jsClassTableSize * sizeof(QV4::InternalClass*));
+        runtimeClasses = (QV4::Heap::InternalClass **)malloc(data->jsClassTableSize * sizeof(QV4::Heap::InternalClass *));
+        // memset the regexps to 0 in case a GC run happens while we're within the loop below
+        memset(runtimeClasses, 0, data->jsClassTableSize * sizeof(QV4::Heap::InternalClass *));
         for (uint i = 0; i < data->jsClassTableSize; ++i) {
             int memberCount = 0;
             const CompiledData::JSClassMember *member = data->jsClassAt(i, &memberCount);
-            QV4::InternalClass *klass = engine->internalClasses(QV4::ExecutionEngine::Class_Object);
+            runtimeClasses[i] = engine->internalClasses(QV4::ExecutionEngine::Class_Object);
             for (int j = 0; j < memberCount; ++j, ++member)
-                klass = klass->addMember(engine->identifierTable->identifier(runtimeStrings[member->nameOffset]), member->isAccessor ? QV4::Attr_Accessor : QV4::Attr_Data);
-
-            runtimeClasses[i] = klass;
+                runtimeClasses[i] = runtimeClasses[i]->addMember(engine->identifierTable->identifier(runtimeStrings[member->nameOffset]), member->isAccessor ? QV4::Attr_Accessor : QV4::Attr_Data);
         }
     }
 
@@ -244,13 +245,28 @@ void CompilationUnit::unlink()
 
 void CompilationUnit::markObjects(QV4::MarkStack *markStack)
 {
-    for (uint i = 0; i < data->stringTableSize; ++i)
-        if (runtimeStrings[i])
-            runtimeStrings[i]->mark(markStack);
+    if (runtimeStrings) {
+        for (uint i = 0; i < data->stringTableSize; ++i)
+            if (runtimeStrings[i])
+                runtimeStrings[i]->mark(markStack);
+    }
     if (runtimeRegularExpressions) {
         for (uint i = 0; i < data->regexpTableSize; ++i)
             runtimeRegularExpressions[i].mark(markStack);
     }
+    if (runtimeClasses) {
+        for (uint i = 0; i < data->jsClassTableSize; ++i)
+            if (runtimeClasses[i])
+                runtimeClasses[i]->mark(markStack);
+    }
+    for (QV4::Function *f : qAsConst(runtimeFunctions))
+        if (f && f->internalClass)
+            f->internalClass->mark(markStack);
+
+    if (runtimeLookups) {
+        for (uint i = 0; i < data->lookupTableSize; ++i)
+            runtimeLookups[i].markObjects(markStack);
+    }
 }
 
 IdentifierHash CompilationUnit::namedObjectsPerComponent(int componentObjectIndex)