WIP: new.target

src/scopes.cc

Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index be991a1a17bc78acc8ae85aae36b4c9e45987979..d8c317779f83c2d5b73c1e9a3c03515fb7df8944 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -156,6 +156,7 @@ void Scope::SetDefaults(ScopeType scope_type, Scope* outer_scope,
   scope_uses_arguments_ = false;
   scope_uses_super_property_ = false;
   scope_uses_this_ = false;
+  scope_uses_new_target_ = false;
   asm_module_ = false;
   asm_function_ = outer_scope != NULL && outer_scope->asm_module_;
   // Inherit the language mode from the parent scope.
@@ -164,6 +165,7 @@ void Scope::SetDefaults(ScopeType scope_type, Scope* outer_scope,
   inner_scope_calls_eval_ = false;
   inner_scope_uses_arguments_ = false;
   inner_scope_uses_this_ = false;
+  inner_scope_uses_new_target_ = false;
   inner_scope_uses_super_property_ = false;
   force_eager_compilation_ = false;
   force_context_allocation_ = (outer_scope != NULL && !is_function_scope())
@@ -316,13 +318,14 @@ void Scope::Initialize() {
     var->AllocateTo(Variable::PARAMETER, -1);
     receiver_ = var;
 
-    if (subclass_constructor) {
-      new_target_ =
-          variables_.Declare(this, ast_value_factory_->new_target_string(),
-                             CONST, Variable::NEW_TARGET, kCreatedInitialized);
-      new_target_->AllocateTo(Variable::PARAMETER, -2);
-      new_target_->set_is_used();
-    }
+    // if (subclass_constructor) {
+    //   new_target_ =
+    //       variables_.Declare(this, ast_value_factory_->new_target_string(),
+    //                          CONST, Variable::NEW_TARGET,
+    //                          kCreatedInitialized);
+    //   new_target_->AllocateTo(Variable::PARAMETER, -2);
+    //   new_target_->set_is_used();
+    // }
   } else {
     DCHECK(outer_scope() != NULL);
     receiver_ = outer_scope()->receiver();
@@ -337,6 +340,9 @@ void Scope::Initialize() {
                        VAR,
                        Variable::ARGUMENTS,
                        kCreatedInitialized);
+
+    variables_.Declare(this, ast_value_factory_->new_target_string(), CONST,
+                       Variable::NEW_TARGET, kNeedsInitialization);
   }
 }
 
@@ -371,6 +377,7 @@ Scope* Scope::FinalizeBlockScope() {
   if (uses_arguments()) outer_scope_->RecordArgumentsUsage();
   if (uses_super_property()) outer_scope_->RecordSuperPropertyUsage();
   if (uses_this()) outer_scope_->RecordThisUsage();
+  if (uses_new_target()) outer_scope_->RecordNewTargetUsage();
 
   return NULL;
 }
@@ -917,12 +924,16 @@ void Scope::Print(int n) {
   if (scope_uses_super_property_)
     Indent(n1, "// scope uses 'super' property\n");
   if (scope_uses_this_) Indent(n1, "// scope uses 'this'\n");
+  if (scope_uses_new_target_) Indent(n1, "// scope uses 'new.target'\n");
   if (inner_scope_uses_arguments_) {
     Indent(n1, "// inner scope uses 'arguments'\n");
   }
   if (inner_scope_uses_super_property_)
     Indent(n1, "// inner scope uses 'super' property\n");
   if (inner_scope_uses_this_) Indent(n1, "// inner scope uses 'this'\n");
+  if (inner_scope_uses_new_target_) {
+    Indent(n1, "// inner scope uses 'new.target'\n");
+  }
   if (outer_scope_calls_sloppy_eval_) {
     Indent(n1, "// outer scope calls 'eval' in sloppy context\n");
   }
@@ -1248,6 +1259,10 @@ void Scope::PropagateScopeInfo(bool outer_scope_calls_sloppy_eval ) {
       if (inner->scope_uses_this_ || inner->inner_scope_uses_this_) {
         inner_scope_uses_this_ = true;
       }
+      if (inner->scope_uses_new_target_ ||
+          inner->inner_scope_uses_new_target_) {
+        inner_scope_uses_new_target_ = true;
+      }
     }
     if (inner->force_eager_compilation_) {
       force_eager_compilation_ = true;
@@ -1379,6 +1394,19 @@ void Scope::AllocateParameterLocals(Isolate* isolate) {
       }
     }
   }
+
+  Variable* new_target = LookupLocal(ast_value_factory_->new_target_string());
+  // Functions have 'new_target' declared implicitly in all non arrow functions.
+  DCHECK(new_target != nullptr || is_arrow_scope());
+
+  if (new_target != nullptr) {
+    if (IsSubclassConstructor(function_kind_)) {
+      new_target->ForceContextAllocation();
+      new_target_ = new_target;
+    } else if (MustAllocate(new_target)) {
+      new_target_ = new_target;
+    }
+  }
 }