Switch CallConstructStub to take new.target in register.

src/mips64/full-codegen-mips64.cc

Index: src/mips64/full-codegen-mips64.cc
diff --git a/src/mips64/full-codegen-mips64.cc b/src/mips64/full-codegen-mips64.cc
index ee76d9d0208551a8b03e1ddd5a0176a332de37ba..ca51ef8e38253ce0e5196e3639b0596d39b81fff 100644
--- a/src/mips64/full-codegen-mips64.cc
+++ b/src/mips64/full-codegen-mips64.cc
@@ -3369,9 +3369,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
       expr->expression()->AsSuperCallReference();
   DCHECK_NOT_NULL(super_call_ref);
 
-  VariableProxy* new_target_proxy = super_call_ref->new_target_var();
-  VisitForStackValue(new_target_proxy);
-
   EmitLoadSuperConstructor(super_call_ref);
   __ push(result_register());
 
@@ -3386,6 +3383,10 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
   // constructor invocation.
   SetConstructCallPosition(expr);
 
+  // Load original constructor into a4.
+  VisitForAccumulatorValue(super_call_ref->new_target_var());
+  __ mov(a4, result_register());
+
   // Load function and argument count into a1 and a0.
   __ li(a0, Operand(arg_count));
   __ ld(a1, MemOperand(sp, arg_count * kPointerSize));
@@ -3406,8 +3407,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
   CallConstructStub stub(isolate(), SUPER_CALL_RECORD_TARGET);
   __ Call(stub.GetCode(), RelocInfo::CONSTRUCT_CALL);
 
-  __ Drop(1);
-
   RecordJSReturnSite(expr);
 
   EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
@@ -4345,6 +4344,9 @@ void FullCodeGenerator::EmitDefaultConstructorCallSuper(CallRuntime* expr) {
   __ CallRuntime(Runtime::kGetPrototype, 1);
   __ Push(result_register());
 
+  // Load original constructor into a4.
+  __ ld(a4, MemOperand(sp, 1 * kPointerSize));
+
   // Check if the calling frame is an arguments adaptor frame.
   Label adaptor_frame, args_set_up, runtime;
   __ ld(a2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));