new classes: implement new.target passing to superclass constructor.

src/arm/full-codegen-arm.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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 244 matching lines @@
     int offset = num_parameters * kPointerSize;
     __ add(r2, fp,
            Operand(StandardFrameConstants::kCallerSPOffset + offset));
     __ mov(r1, Operand(Smi::FromInt(num_parameters)));
     __ Push(r3, r2, r1);
 
     // Arguments to ArgumentsAccessStub:
     //   function, receiver address, parameter count.
     // The stub will rewrite receiever and parameter count if the previous
     // stack frame was an arguments adapter frame.
+    ArgumentsAccessStub::HasNewTarget has_new_target =
+        IsSubclassConstructor(info->function()->kind())

[arv (Not doing code reviews), 2015/02/10 20:15:18]

Do we do the right thing in the following case?

class C {
  constructor() {
    assertEquals(C, new.target);
  }
}
new C();

The function above is not a subclass constructor.

Maybe this is just a TODO?


Maybe add a function to SHF called, HasNewTarget()?

[Dmitry Lomov (no reviews), 2015/02/11 00:58:29]

Yes, we do not support new.target in general yet, just passing new.target
through subclass constructor.
I will add that when we support new.target proper

+            ? ArgumentsAccessStub::HAS_NEW_TARGET
+            : ArgumentsAccessStub::NO_NEW_TARGET;
     ArgumentsAccessStub::Type type;
     if (is_strict(language_mode())) {
       type = ArgumentsAccessStub::NEW_STRICT;
     } else if (function()->has_duplicate_parameters()) {
       type = ArgumentsAccessStub::NEW_SLOPPY_SLOW;
     } else {
       type = ArgumentsAccessStub::NEW_SLOPPY_FAST;
     }
-    ArgumentsAccessStub stub(isolate(), type);
+    ArgumentsAccessStub stub(isolate(), type, has_new_target);
     __ CallStub(&stub);
 
     SetVar(arguments, r0, r1, r2);
   }
 
   if (FLAG_trace) {
     __ CallRuntime(Runtime::kTraceEnter, 0);
   }
 
   // Visit the declarations and body unless there is an illegal
@@ skipping 159 matching lines @@
     __ bind(&ok);
 
 #ifdef DEBUG
     // Add a label for checking the size of the code used for returning.
     Label check_exit_codesize;
     __ bind(&check_exit_codesize);
 #endif
     // Make sure that the constant pool is not emitted inside of the return
     // sequence.
     { Assembler::BlockConstPoolScope block_const_pool(masm_);
-      int32_t sp_delta = (info_->scope()->num_parameters() + 1) * kPointerSize;
+      int32_t arg_count = info_->scope()->num_parameters() + 1;
+      if (FLAG_experimental_classes &&
+          IsSubclassConstructor(info_->function()->kind())) {
+        arg_count++;
+      }
+      int32_t sp_delta = arg_count * kPointerSize;
       CodeGenerator::RecordPositions(masm_, function()->end_position() - 1);
       // TODO(svenpanne) The code below is sometimes 4 words, sometimes 5!
       PredictableCodeSizeScope predictable(masm_, -1);
       __ RecordJSReturn();
       int no_frame_start = __ LeaveFrame(StackFrame::JAVA_SCRIPT);
       { ConstantPoolUnavailableScope constant_pool_unavailable(masm_);
         __ add(sp, sp, Operand(sp_delta));
         __ Jump(lr);
         info_->AddNoFrameRange(no_frame_start, masm_->pc_offset());
       }
@@ skipping 2786 matching lines @@
   __ mov(r3, Operand(SmiFromSlot(expr->CallNewFeedbackSlot())));
 
   CallConstructStub stub(isolate(), RECORD_CONSTRUCTOR_TARGET);
   __ Call(stub.GetCode(), RelocInfo::CONSTRUCT_CALL);
   PrepareForBailoutForId(expr->ReturnId(), TOS_REG);
   context()->Plug(r0);
 }
 
 
 void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
+  Comment cmnt(masm_, "[ SuperConstructorCall");
+  Variable* new_target_var = scope()->DeclarationScope()->new_target_var();
+  GetVar(result_register(), new_target_var);
+  __ Push(result_register());
+
   SuperReference* super_ref = expr->expression()->AsSuperReference();
   EmitLoadSuperConstructor(super_ref);
   __ push(result_register());
 
   Variable* this_var = super_ref->this_var()->var();
 
   GetVar(r0, this_var);
   __ CompareRoot(r0, Heap::kTheHoleValueRootIndex);
   Label uninitialized_this;
   __ b(eq, &uninitialized_this);
@@ skipping 23 matching lines @@
     /* TODO(dslomov): support pretenuring.
     EnsureSlotContainsAllocationSite(expr->AllocationSiteFeedbackSlot());
     DCHECK(expr->AllocationSiteFeedbackSlot().ToInt() ==
            expr->CallNewFeedbackSlot().ToInt() + 1);
     */
   }
 
   __ Move(r2, FeedbackVector());
   __ mov(r3, Operand(SmiFromSlot(expr->CallFeedbackSlot())));
 
-  // TODO(dslomov): use a different stub and propagate new.target.
-  CallConstructStub stub(isolate(), RECORD_CONSTRUCTOR_TARGET);
+  CallConstructStub stub(isolate(), SUPER_CALL_RECORD_TARGET);
   __ Call(stub.GetCode(), RelocInfo::CONSTRUCT_CALL);
 
+  __ Drop(1);
+
   RecordJSReturnSite(expr);
 
   EmitVariableAssignment(this_var, Token::INIT_CONST);
   context()->Plug(r0);
 }
 
 
 void FullCodeGenerator::EmitIsSmi(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);
@@ skipping 2109 matching lines @@
 
   DCHECK(interrupt_address ==
          isolate->builtins()->OsrAfterStackCheck()->entry());
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM