Add the ability to explicitly enable the code cache in qmljs

This also requires mapping the label pointers in the byte code back to
the instruction enum. Fortunately this reverse mapping is only needed in
the qmljs case. Normally in the QML engine we persist the byte-code to
disk before linking the compilation unit to the engine (where we map the
enum to goto labels).

Change-Id: If0b79288274bb1031161841b63a85f164502aaec
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 38 insertions, 7 deletions

diff --git a/tools/qmljs/qmljs.cpp b/tools/qmljs/qmljs.cpp
index b4ffc9be16..4b63357363 100644
--- a/tools/qmljs/qmljs.cpp
+++ b/tools/qmljs/qmljs.cpp
@@ -51,6 +51,8 @@ QT_REQUIRE_CONFIG(qml_interpreter);
 
 #include <QtCore/QCoreApplication>
 #include <QtCore/QFile>
+#include <QtCore/QFileInfo>
+#include <QtCore/QDateTime>
 #include <private/qqmljsengine_p.h>
 #include <private/qqmljslexer_p.h>
 #include <private/qqmljsparser_p.h>
@@ -147,6 +149,7 @@ int main(int argc, char *argv[])
 #endif
 
     bool runAsQml = false;
+    bool cache = false;
 
     if (!args.isEmpty()) {
         if (args.first() == QLatin1String("--jit")) {
@@ -166,6 +169,11 @@ int main(int argc, char *argv[])
             args.removeFirst();
         }
 
+        if (args.first() == QLatin1String("--cache")) {
+            cache = true;
+            args.removeFirst();
+        }
+
         if (args.first() == QLatin1String("--help")) {
             std::cerr << "Usage: qmljs [|--jit|--interpret|--qml] file..." << std::endl;
             return EXIT_SUCCESS;
@@ -199,15 +207,38 @@ int main(int argc, char *argv[])
         for (const QString &fn : qAsConst(args)) {
             QFile file(fn);
             if (file.open(QFile::ReadOnly)) {
-                const QString code = QString::fromUtf8(file.readAll());
-                file.close();
+                QScopedPointer<QV4::Script> script;
+                if (cache && QFile::exists(fn + QLatin1Char('c'))) {
+                    QQmlRefPointer<QV4::CompiledData::CompilationUnit> unit = iSelFactory->createUnitForLoading();
+                    QString error;
+                    if (unit->loadFromDisk(QUrl::fromLocalFile(fn), iSelFactory, &error)) {
+                        script.reset(new QV4::Script(&vm, nullptr, unit));
+                    } else {
+                        std::cout << "Error loading" << qPrintable(fn) << "from disk cache:" << qPrintable(error) << std::endl;
+                    }
+                }
+                if (!script) {
+                    const QString code = QString::fromUtf8(file.readAll());
+                    file.close();
 
+                    script.reset(new QV4::Script(ctx, code, fn));
+                    script->parseAsBinding = runAsQml;
+                    script->parse();
+                }
                 QV4::ScopedValue result(scope);
-                QV4::Script script(ctx, code, fn);
-                script.parseAsBinding = runAsQml;
-                script.parse();
-                if (!scope.engine->hasException)
-                    result = script.run();
+                if (!scope.engine->hasException) {
+                    const auto unit = script->compilationUnit;
+                    if (cache && unit && !(unit->data->flags & QV4::CompiledData::Unit::StaticData)) {
+                        if (unit->data->sourceTimeStamp == 0) {
+                            const_cast<QV4::CompiledData::Unit*>(unit->data)->sourceTimeStamp = QFileInfo(fn).lastModified().toMSecsSinceEpoch();
+                        }
+                        QString saveError;
+                        if (!unit->saveToDisk(QUrl::fromLocalFile(fn), &saveError)) {
+                            std::cout << "Error saving JS cache file: " << qPrintable(saveError) << std::endl;
+                        }
+                    }
+                    result = script->run();
+                }
                 if (scope.engine->hasException) {
                     QV4::StackTrace trace;
                     QV4::ScopedValue ex(scope, scope.engine->catchException(&trace));