MIPS: [runtime] Throw exception for derived constructors in correct context.

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index d06fc8c88a76a8a1358e717dc4b67c6082097688..dc8d180d95a51138085bf9054f53d07c27904bd1 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -425,7 +425,8 @@ void Builtins::Generate_InOptimizationQueue(MacroAssembler* masm) {
 
 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                            bool is_api_function,
-                                           bool create_implicit_receiver) {
+                                           bool create_implicit_receiver,
+                                           bool check_derived_construct) {
   // ----------- S t a t e -------------
   //  -- a0     : number of arguments
   //  -- a1     : constructor function
@@ -684,6 +685,20 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     // Leave construct frame.
   }
 
+  // ES6 9.2.2. Step 13+
+  // Check that the result is not a Smi, indicating that the constructor result
+  // from a derived class is neither undefined nor an Object.
+  if (check_derived_construct) {
+    Label dont_throw;
+    __ JumpIfNotSmi(v0, &dont_throw);
+    {
+      FrameScope scope(masm, StackFrame::INTERNAL);
+      __ push(v0);

[Camillo Bruni, 2016/01/15 13:51:47]

Sorry, I figured out that I don't have to pass an argument to the runtime
function, so you could drop the push here.

[balazs.kilvady, 2016/01/15 13:59:44]

Done.

+      __ CallRuntime(Runtime::kThrowDerivedConstructorReturnedNonObject);
+    }
+    __ bind(&dont_throw);
+  }
+
   __ sll(t0, a1, kPointerSizeLog2 - 1);
   __ Addu(sp, sp, t0);
   __ Addu(sp, sp, kPointerSize);
@@ -695,23 +710,23 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
 
 
 void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, true);
+  Generate_JSConstructStubHelper(masm, false, true, false);
 }
 
 
 void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, true, true);
+  Generate_JSConstructStubHelper(masm, true, true, false);
 }
 
 
 void Builtins::Generate_JSBuiltinsConstructStub(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, false);
+  Generate_JSConstructStubHelper(masm, false, false, false);
 }
 
 
 void Builtins::Generate_JSBuiltinsConstructStubForDerived(
     MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, false);
+  Generate_JSConstructStubHelper(masm, false, false, true);
 }