[Turbofan] Implement super calls with spread bytecode in assembly code.

src/builtins/x64/builtins-x64.cc

Index: src/builtins/x64/builtins-x64.cc
diff --git a/src/builtins/x64/builtins-x64.cc b/src/builtins/x64/builtins-x64.cc
index a292d70c71c6a4cd4878b9321ba12b078427e311..ca1b222441766bc165fdf335348782c07935b3f5 100644
--- a/src/builtins/x64/builtins-x64.cc
+++ b/src/builtins/x64/builtins-x64.cc
@@ -2883,6 +2883,114 @@ void Builtins::Generate_Construct(MacroAssembler* masm) {
           RelocInfo::CODE_TARGET);
 }
 
+// static
+void Builtins::Generate_ConstructWithSpread(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rax : the number of arguments (not including the receiver)
+  //  -- rdx : the new target (either the same as the constructor or
+  //           the JSFunction on which new was invoked initially)
+  //  -- rdi : the constructor to call (can be any Object)
+  // -----------------------------------
+
+  // Make sure the target is actually a constructor.
+  Label target_not_constructor;

[Benedikt Meurer, 2016/12/15 11:59:52]

These checks must not be performed before the evaluation of the spread. So just
let the Construct builtin deal with this.

[petermarshall, 2016/12/15 13:37:27]

Yep cool

+  __ JumpIfSmi(rdi, &target_not_constructor, Label::kFar);
+  __ movp(rcx, FieldOperand(rdi, HeapObject::kMapOffset));
+  __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
+           Immediate(1 << Map::kIsConstructor));
+  __ j(zero, &target_not_constructor, Label::kFar);
+
+  // Make sure the new target is actually a constructor.
+  Label new_target_not_constructor;

[Benedikt Meurer, 2016/12/15 11:59:52]

Same for new.target

+  __ JumpIfSmi(rdx, &new_target_not_constructor, Label::kFar);
+  __ movp(rcx, FieldOperand(rdx, HeapObject::kMapOffset));
+  __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
+           Immediate(1 << Map::kIsConstructor));
+  __ j(zero, &new_target_not_constructor, Label::kFar);
+
+  // Load the spread argument.
+  __ movp(rbx, Operand(rsp, kPointerSize));
+  {
+    // Call the builtin for the result of the spread.
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ Push(rdi);  // target
+    __ Push(rdx);  // new target
+    __ Integer32ToSmi(rax, rax);
+    __ Push(rax);  // nargs
+    __ Push(rbx);
+    __ CallRuntime(Runtime::kSpreadIterablePrepareFixed);
+    __ movp(rbx, rax);
+    __ Pop(rax);  // nargs
+    __ SmiToInteger32(rax, rax);
+    __ Pop(rdx);  // new target
+    __ Pop(rdi);  // target
+  }
+
+  {
+    // Pop the return address and spread argument.
+    __ PopReturnAddressTo(r8);
+    __ Pop(rcx);
+
+    // Calculate the new nargs including the result of the spread.
+    __ SmiToInteger32(r9, FieldOperand(rbx, FixedArray::kLengthOffset));
+    __ addp(rax, r9);

[Benedikt Meurer, 2016/12/15 11:59:52]

You can combine these addp and subp into a single leap

[petermarshall, 2016/12/15 13:37:27]

I always thought leap was a funny instruction name, it sounds like a jump
instruction to somewhere very far away =P. That objection aside, SGTM.

+    __ subp(rax, Immediate(1));  // Subtract 1 for the spread itself.
+  }
+
+  // Check for stack overflow.
+  {
+    // Check the stack for overflow. We are not trying to catch interruptions
+    // (i.e. debug break and preemption) here, so check the "real stack limit".
+    Label done;
+    __ LoadRoot(kScratchRegister, Heap::kRealStackLimitRootIndex);
+    __ movp(rcx, rsp);
+    // Make rcx the space we have left. The stack might already be overflowed
+    // here which will cause rcx to become negative.
+    __ subp(rcx, kScratchRegister);
+    __ sarp(rcx, Immediate(kPointerSizeLog2));
+    // Check if the arguments will overflow the stack.
+    __ cmpp(rcx, r9);
+    __ j(greater, &done, Label::kNear);  // Signed comparison.
+    __ TailCallRuntime(Runtime::kThrowStackOverflow);
+    __ bind(&done);
+  }
+
+  // Put the evaluated spread onto the stack as additional arguments.
+  {
+    __ Set(rcx, 0);
+    Label done, loop;
+    __ bind(&loop);
+    __ cmpl(rcx, r9);
+    __ j(equal, &done, Label::kNear);
+    __ movp(kScratchRegister, FieldOperand(rbx, rcx, times_pointer_size,
+                                           FixedArray::kHeaderSize));
+    __ Push(kScratchRegister);
+    __ incl(rcx);
+    __ jmp(&loop);
+    __ bind(&done);
+    __ PushReturnAddressFrom(r8);
+  }
+
+  // Dispatch
+  { __ Jump(masm->isolate()->builtins()->Construct(), RelocInfo::CODE_TARGET); }
+
+  // The target is not a constructor, throw an appropriate TypeError.
+  __ bind(&target_not_constructor);
+  {
+    StackArgumentsAccessor args(rsp, 0);
+    __ movp(args.GetReceiverOperand(), rdi);
+    __ TailCallRuntime(Runtime::kThrowCalledNonCallable);
+  }
+
+  // The new.target is not a constructor, throw an appropriate TypeError.
+  __ bind(&new_target_not_constructor);
+  {
+    StackArgumentsAccessor args(rsp, 0);
+    __ movp(args.GetReceiverOperand(), rdx);
+    __ TailCallRuntime(Runtime::kThrowCalledNonCallable);
+  }
+}
+
 static void CompatibleReceiverCheck(MacroAssembler* masm, Register receiver,
                                     Register function_template_info,
                                     Register scratch0, Register scratch1,