Fix memory leak with QtQuick compiler generated files

When for the QQC code path we do QML type re-compilation, we allocate a
new QV4::CompiledData::Unit. We must make sure that this dynamically
allocated memory is released in QV4::CompiledData::CompilationUnit's
destructor, by ensuring that the StaticData flag is not set.

This isn't directly applicable to the ahead-of-time generated cache file
unit data as they will always be re-generated (and thus the unsetting of
StaticData at the end of createCompilationUnit::createUnitData()), but
I've added a test-case nevertheless to ensure the correct engine
behavior.

Change-Id: I16973d7989567892bf8bf9dd6214bf293055d260
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index 9749324060..e82fe71934 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -1397,6 +1397,9 @@ QV4::CompiledData::Unit *QmlUnitGenerator::generate(Document &output, const QV4:
     QV4::CompiledData::Unit *qmlUnit = reinterpret_cast<QV4::CompiledData::Unit *>(data);
     qmlUnit->unitSize = totalSize;
     qmlUnit->flags |= QV4::CompiledData::Unit::IsQml;
+    // This unit's memory was allocated with malloc on the heap, so it's
+    // definitely not suitable for StaticData access.
+    qmlUnit->flags &= ~QV4::CompiledData::Unit::StaticData;
     qmlUnit->offsetToImports = unitSize;
     qmlUnit->nImports = output.imports.count();
     qmlUnit->offsetToObjects = unitSize + importSize;