[Interpreter] Support for operator new.

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index 03f6fa2fd545ae565588ef65a76f7ef44ab47854..8538ac596b978f483df27dd2960cc9a46bf9dd20 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -795,7 +795,7 @@ void Builtins::Generate_InterpreterPushArgsAndCall(MacroAssembler* masm) {
   //  -- rdi : the target to call (can be any Object).
 
   // Pop return address to allow tail-call after pushing arguments.
-  __ Pop(rdx);
+  __ PopReturnAddressTo(kScratchRegister);
 
   // Find the address of the last argument.
   __ movp(rcx, rax);
@@ -815,11 +815,51 @@ void Builtins::Generate_InterpreterPushArgsAndCall(MacroAssembler* masm) {
   __ j(greater, &loop_header, Label::kNear);
 
   // Call the target.
-  __ Push(rdx);  // Re-push return address.
+  __ PushReturnAddressFrom(kScratchRegister);  // Re-push return address.
   __ Jump(masm->isolate()->builtins()->Call(), RelocInfo::CODE_TARGET);
 }
 
 
+// static
+void Builtins::Generate_InterpreterPushArgsAndConstruct(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rax : the number of arguments (not including the receiver)
+  //  -- rdx : the original constructor (either the same as the constructor or
+  //           the JSFunction on which new was invoked initially)
+  //  -- rdi : the constructor to call (can be any Object)
+  //  -- rbx : the address of the first argument to be pushed. Subsequent
+  //           arguments should be consecutive above this, in the same order as
+  //           they are to be pushed onto the stack.
+  // -----------------------------------
+
+  // Pop return address to allow tail-call after pushing arguments.
+  __ PopReturnAddressTo(kScratchRegister);
+
+  // Find the address of the last argument.
+  __ movp(rcx, rax);
+  __ addp(rcx, Immediate(1));  // Add one for receiver.
+  __ shlp(rcx, Immediate(kPointerSizeLog2));
+  __ negp(rcx);
+  __ addp(rcx, rbx);
+
+  // Push the arguments.
+  Label loop_header, loop_check;
+  __ j(always, &loop_check);
+  __ bind(&loop_header);
+  __ Push(Operand(rbx, 0));
+  __ subp(rbx, Immediate(kPointerSize));
+  __ bind(&loop_check);
+  __ cmpp(rbx, rcx);
+  __ j(greater, &loop_header, Label::kNear);
+
+  // Push return address in preparation for the tail-call.
+  __ PushReturnAddressFrom(kScratchRegister);

[rmcilroy, 2015/10/13 14:07:30]

nit - could we create a helper function for the arg pushing assembly which is
shared between PushArgsAndCall and PushArgsAndConstruct.

[oth, 2015/10/14 08:40:09]

Done.

+
+  // Call the target.
+  __ Jump(masm->isolate()->builtins()->Construct(), RelocInfo::CONSTRUCT_CALL);
+}
+
+
 void Builtins::Generate_CompileLazy(MacroAssembler* masm) {
   CallRuntimePassFunction(masm, Runtime::kCompileLazy);
   GenerateTailCallToReturnedCode(masm);