3 files changed, 55 insertions, 16 deletions

diff --git a/src/v4/qmljs_engine.cpp b/src/v4/qmljs_engine.cpp
index 126162e38f..33ac4a2769 100644
--- a/src/v4/qmljs_engine.cpp
+++ b/src/v4/qmljs_engine.cpp
@@ -58,13 +58,14 @@
 #include <qv4stringobject.h>
 #include <qv4identifier.h>
 #include <qv4unwindhelper.h>
+#include "qv4isel_masm_p.h"
+#include "debugging.h"
 
 namespace QQmlJS {
 namespace VM {
 
 ExecutionEngine::ExecutionEngine(EvalISelFactory *factory)
     : memoryManager(new QQmlJS::VM::MemoryManager)
-    , iselFactory(factory)
     , debugger(0)
     , globalObject(Value::nullValue())
     , globalCode(0)
@@ -72,6 +73,10 @@ ExecutionEngine::ExecutionEngine(EvalISelFactory *factory)
 {
     MemoryManager::GCBlocker gcBlocker(memoryManager);
 
+    if (!factory)
+        factory = new MASM::ISelFactory;
+    iselFactory.reset(factory);
+
     memoryManager->setExecutionEngine(this);
 
     identifierCache = new Identifiers(this);
@@ -453,5 +458,25 @@ void ExecutionEngine::markObjects()
     id_eval->mark();
 }
 
+Value ExecutionEngine::run(Function *function, ExecutionContext *ctx)
+{
+    if (!ctx)
+        ctx = rootContext;
+
+    TemporaryAssignment<Function*>(globalCode, function);
+
+    // ### Would be better to have a SavedExecutionState object that
+    // saves this and restores it in the destructor (to survive an exception).
+    ctx->strictMode = function->isStrict;
+    ctx->lookups = function->lookups;
+
+    if (debugger)
+        debugger->aboutToCall(0, ctx);
+    QQmlJS::VM::Value result = function->code(ctx, function->codeData);
+    if (debugger)
+        debugger->justLeft(ctx);
+    return result;
+}
+
 } // namespace VM
 } // namespace QQmlJS
diff --git a/src/v4/qmljs_engine.h b/src/v4/qmljs_engine.h
index 0d8dd05fc3..1440a6461e 100644
--- a/src/v4/qmljs_engine.h
+++ b/src/v4/qmljs_engine.h
@@ -102,7 +102,7 @@ class RegExp;
 struct Q_V4_EXPORT ExecutionEngine
 {
     MemoryManager *memoryManager;
-    EvalISelFactory *iselFactory;
+    QScopedPointer<EvalISelFactory> iselFactory;
     ExecutionContext *current;
     ExecutionContext *rootContext;
     WTF::BumpPointerAllocator bumperPointerAllocator; // Used by Yarr Regex engine.
@@ -182,7 +182,7 @@ struct Q_V4_EXPORT ExecutionEngine
 
     QVector<Function *> functions;
 
-    ExecutionEngine(EvalISelFactory *iselFactory);
+    ExecutionEngine(EvalISelFactory *iselFactory = 0);
     ~ExecutionEngine();
 
     ExecutionContext *newContext();
@@ -223,6 +223,28 @@ struct Q_V4_EXPORT ExecutionEngine
     void requireArgumentsAccessors(int n);
 
     void markObjects();
+
+    Value run(VM::Function *function, ExecutionContext *ctx = 0);
+};
+
+template <typename T>
+struct TemporaryAssignment
+{
+    TemporaryAssignment(T &var, const T& temporaryValue)
+        : variable(var)
+        , savedValue(var)
+    {
+        variable = temporaryValue;
+    }
+    ~TemporaryAssignment()
+    {
+        variable = savedValue;
+    }
+    T &variable;
+    T savedValue;
+private:
+    TemporaryAssignment(const TemporaryAssignment<T>&);
+    TemporaryAssignment operator=(const TemporaryAssignment<T>&);
 };
 
 } // namespace VM
diff --git a/tools/v4/main.cpp b/tools/v4/main.cpp
index 89a25973e8..03ba82851c 100644
--- a/tools/v4/main.cpp
+++ b/tools/v4/main.cpp
@@ -337,14 +337,14 @@ int main(int argc, char *argv[])
 #endif // QMLJS_WITH_LLVM
     case use_masm:
     case use_moth: {
-        QScopedPointer<QQmlJS::EvalISelFactory> iSelFactory;
+        QQmlJS::EvalISelFactory* iSelFactory = 0;
         if (mode == use_moth) {
-            iSelFactory.reset(new QQmlJS::Moth::ISelFactory);
+            iSelFactory = new QQmlJS::Moth::ISelFactory;
         } else {
-            iSelFactory.reset(new QQmlJS::MASM::ISelFactory);
+            iSelFactory = new QQmlJS::MASM::ISelFactory;
         }
 
-        QQmlJS::VM::ExecutionEngine vm(iSelFactory.data());
+        QQmlJS::VM::ExecutionEngine vm(iSelFactory);
 
         QScopedPointer<QQmlJS::Debugging::Debugger> debugger;
         if (enableDebugging)
@@ -375,15 +375,7 @@ int main(int argc, char *argv[])
                                                                                     /*strictMode =*/ false, /*inheritContext =*/ false);
                     if (!f)
                         continue;
-                    vm.globalCode = f;
-
-                    ctx->strictMode = f->isStrict;
-                    ctx->lookups = f->lookups;
-                    if (debugger)
-                        debugger->aboutToCall(0, ctx);
-                    QQmlJS::VM::Value result = f->code(ctx, f->codeData);
-                    if (debugger)
-                        debugger->justLeft(ctx);
+                    QQmlJS::VM::Value result = vm.run(f);
                     if (!result.isUndefined()) {
                         if (! qgetenv("SHOW_EXIT_VALUE").isEmpty())
                             std::cout << "exit value: " << qPrintable(result.toString(ctx)->toQString()) << std::endl;