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

src/mips/builtins-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_MIPS
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 407 matching lines @@
   CallRuntimePassFunction(masm, Runtime::kTryInstallOptimizedCode);
   GenerateTailCallToReturnedCode(masm);
 
   __ bind(&ok);
   GenerateTailCallToSharedCode(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
   //  -- a2     : allocation site or undefined
   //  -- a3     : new target
   //  -- ra     : return address
   //  -- sp[...]: constructor arguments
   // -----------------------------------
 
   Isolate* isolate = masm->isolate();
@@ skipping 238 matching lines @@
       // sp[0]: receiver (newly allocated object)
       // sp[1]: number of arguments (smi-tagged)
       __ lw(a1, MemOperand(sp, 1 * kPointerSize));
     } else {
       __ lw(a1, MemOperand(sp));
     }
 
     // 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);
   if (create_implicit_receiver) {
     __ IncrementCounter(isolate->counters()->constructed_objects(), 1, a1, a2);
   }
   __ Ret();
 }
 
 
 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);
 }
 
 
 void Builtins::Generate_ConstructedNonConstructable(MacroAssembler* masm) {
   FrameScope scope(masm, StackFrame::INTERNAL);
   __ Push(a1);
   __ CallRuntime(Runtime::kThrowConstructedNonConstructable);
 }
 
 
@@ skipping 1820 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS