[V8] Introduce a QML compilation mode

In QML mode, there is a second global object - known as the QML
global object.  During property resolution, if a property is not
present on the JS global object, it is resolved on the QML global
object.

This global object behavior is only enabled if a script is being
compiled in QML mode.  The object to use as the QML global object
is passed as a parameter to the Script::Run() method.  Any function
closures etc. created during the run will retain a reference to this
object, so different objects can be passed in different script
runs.

Change-Id: I75d6f8173260e0d4933fd33ad16a277542048f09
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/src/3rdparty/v8/src/parser.cc b/src/3rdparty/v8/src/parser.cc
index 129bd95..da4685f 100644
--- a/src/3rdparty/v8/src/parser.cc
+++ b/src/3rdparty/v8/src/parser.cc
@@ -639,6 +639,9 @@ FunctionLiteral* Parser::DoParseProgram(CompilationInfo* info,
 
     FunctionState function_state(this, scope, isolate());  // Enters 'scope'.
     top_scope_->SetLanguageMode(info->language_mode());
+    if (info->is_qml_mode()) {
+      scope->EnableQmlModeFlag();
+    }
     ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(16, zone());
     bool ok = true;
     int beg_loc = scanner().location().beg_pos;
@@ -745,6 +748,9 @@ FunctionLiteral* Parser::ParseLazy(Utf16CharacterStream* source,
            info()->is_extended_mode());
     ASSERT(info()->language_mode() == shared_info->language_mode());
     scope->SetLanguageMode(shared_info->language_mode());
+    if (shared_info->qml_mode()) {
+      top_scope_->EnableQmlModeFlag();
+    }
     FunctionLiteral::Type type = shared_info->is_expression()
         ? (shared_info->is_anonymous()
               ? FunctionLiteral::ANONYMOUS_EXPRESSION
@@ -1782,6 +1788,25 @@ void Parser::Declare(Declaration* declaration, bool resolve, bool* ok) {
   // both access to the static and the dynamic context chain; the
   // runtime needs to provide both.
   if (resolve && var != NULL) {
+    if (declaration_scope->is_qml_mode()) {
+      Handle<GlobalObject> global = isolate_->global_object();
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+      if (isolate_->debug()->IsLoaded() && isolate_->debug()->InDebugger()) {
+        // Get the context before the debugger was entered.
+        SaveContext *save = isolate_->save_context();
+        while (save != NULL && *save->context() == *isolate_->debug()->debug_context())
+          save = save->prev();
+
+        global = Handle<GlobalObject>(save->context()->global_object());
+      }
+#endif
+
+      if (!global->HasProperty(*(proxy->name()))) {
+        var->set_is_qml_global(true);
+      }
+    }
+
     proxy->BindTo(var);
 
     if (FLAG_harmony_modules) {
@@ -2219,6 +2244,12 @@ Block* Parser::ParseVariableDeclarations(
         arguments->Add(value, zone());
         value = NULL;  // zap the value to avoid the unnecessary assignment
 
+        int qml_mode = 0;
+        if (top_scope_->is_qml_mode()
+                && !Isolate::Current()->global_object()->HasProperty(*name))
+          qml_mode = 1;
+        arguments->Add(factory()->NewNumberLiteral(qml_mode), zone());
+
         // Construct the call to Runtime_InitializeConstGlobal
         // and add it to the initialization statement block.
         // Note that the function does different things depending on
@@ -2233,6 +2264,12 @@ Block* Parser::ParseVariableDeclarations(
         LanguageMode language_mode = initialization_scope->language_mode();
         arguments->Add(factory()->NewNumberLiteral(language_mode), zone());
 
+        int qml_mode = 0;
+        if (top_scope_->is_qml_mode()
+                && !Isolate::Current()->global_object()->HasProperty(*name))
+          qml_mode = 1;
+        arguments->Add(factory()->NewNumberLiteral(qml_mode), zone());
+
         // Be careful not to assign a value to the global variable if
         // we're in a with. The initialization value should not
         // necessarily be stored in the global object in that case,