V4: Collect trace information in the interpreter

Collect type information about values used in a function. These include
all parameters, and the results of many bytecode instructions. For array
loads/stores, it also tracks if the access is in-bounds of a
SimpleArrayData.

Collection is only enabled when the qml-tracing feature is turned on
while configuring.

In subsequent patches this is used to generated optimized JITted code.

Change-Id: I63985c334c3fdc55fca7fb4addfe3e535989aac5
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 43 insertions, 4 deletions

diff --git a/src/qml/jsruntime/qv4function_p.h b/src/qml/jsruntime/qv4function_p.h
index 86343ea061..374e46b929 100644
--- a/src/qml/jsruntime/qv4function_p.h
+++ b/src/qml/jsruntime/qv4function_p.h
@@ -64,10 +64,24 @@ struct QQmlSourceLocation;
 
 namespace QV4 {
 
-struct Q_QML_EXPORT Function {
-    const CompiledData::Function *compiledFunction;
+struct Q_QML_EXPORT FunctionData {
     CompiledData::CompilationUnit *compilationUnit;
 
+    FunctionData(CompiledData::CompilationUnit *compilationUnit)
+        : compilationUnit(compilationUnit)
+    {}
+};
+// Make sure this class can be accessed through offsetof (done by the assemblers):
+Q_STATIC_ASSERT(std::is_standard_layout< FunctionData >::value);
+
+struct Q_QML_EXPORT Function : public FunctionData {
+private:
+    Function(ExecutionEngine *engine, CompiledData::CompilationUnit *unit, const CompiledData::Function *function);
+    ~Function();
+
+public:
+    const CompiledData::Function *compiledFunction;
+
     ReturnedValue call(const Value *thisObject, const Value *argv, int argc, const ExecutionContext *context);
 
     const char *codeData;
@@ -83,8 +97,8 @@ struct Q_QML_EXPORT Function {
     bool hasQmlDependencies;
     bool isEval = false;
 
-    Function(ExecutionEngine *engine, CompiledData::CompilationUnit *unit, const CompiledData::Function *function);
-    ~Function();
+    static Function *create(ExecutionEngine *engine, CompiledData::CompilationUnit *unit, const CompiledData::Function *function);
+    void destroy();
 
     // used when dynamically assigning signal handlers (QQmlConnection)
     void updateInternalClass(ExecutionEngine *engine, const QList<QByteArray> &parameters);
@@ -110,6 +124,31 @@ struct Q_QML_EXPORT Function {
             return nullptr;
         return compilationUnit->runtimeFunctions[compiledFunction->nestedFunctionIndex];
     }
+
+    Q_NEVER_INLINE QString traceInfoToString();
+
+    quint8 *traceInfo(uint i)
+    {
+#if QT_CONFIG(qml_tracing)
+        Q_ASSERT((tracingEnabled() && i < traceInfoCount()) || (i == 0));
+        return reinterpret_cast<quint8 *>(this) + sizeof(Function) + i;
+#else
+        Q_UNUSED(i);
+        return nullptr;
+#endif
+    }
+
+    quint32 traceInfoCount() const
+    { return compiledFunction->nTraceInfos; }
+
+    bool tracingEnabled() const
+    {
+#if QT_CONFIG(qml_tracing)
+        return traceInfoCount() != CompiledData::Function::NoTracing();
+#else
+        return false;
+#endif
+    }
 };
 
 }