[runtime] Introduce dedicated JSBoundFunction to represent bound functions.

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 eba09acd24240c892478e30461a6c6d83304551a..5c9d6eb85de500eaa67bcdbe203118e623f02e17 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -1973,6 +1973,116 @@ void Builtins::Generate_CallFunction(MacroAssembler* masm,
 }
 
 
+namespace {
+
+void Generate_PushBoundArguments(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rax : the number of arguments (not including the receiver)
+  //  -- rdx : new.target (only in case of [[Construct]])
+  //  -- rdi : target (checked to be a JSBoundFunction)
+  // -----------------------------------
+
+  // Load [[BoundArguments]] into rcx and length of that into rbx.
+  Label no_bound_arguments;
+  __ movp(rcx, FieldOperand(rdi, JSBoundFunction::kBoundArgumentsOffset));
+  __ SmiToInteger32(rbx, FieldOperand(rcx, FixedArray::kLengthOffset));
+  __ testl(rbx, rbx);
+  __ j(zero, &no_bound_arguments);
+  {
+    // ----------- S t a t e -------------
+    //  -- rax : the number of arguments (not including the receiver)
+    //  -- rdx : new.target (only in case of [[Construct]])
+    //  -- rdi : target (checked to be a JSBoundFunction)
+    //  -- rcx : the [[BoundArguments]] (implemented as FixedArray)
+    //  -- rbx : the number of [[BoundArguments]] (checked to be non-zero)
+    // -----------------------------------
+
+    // Reserve stack space for the [[BoundArguments]].
+    {
+      Label done;
+      __ leap(kScratchRegister, Operand(rbx, times_pointer_size, 0));
+      __ subp(rsp, kScratchRegister);
+      // 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".
+      __ CompareRoot(rsp, Heap::kRealStackLimitRootIndex);
+      __ j(greater, &done, Label::kNear);  // Signed comparison.
+      // Restore the stack pointer.
+      __ leap(rsp, Operand(rsp, rbx, times_pointer_size, 0));
+      {
+        FrameScope scope(masm, StackFrame::MANUAL);
+        __ EnterFrame(StackFrame::INTERNAL);
+        __ CallRuntime(Runtime::kThrowStackOverflow, 0);
+      }
+      __ bind(&done);
+    }
+
+    // Adjust effective number of arguments to include return address.
+    __ incl(rax);
+
+    // Relocate arguments and return address down the stack.
+    {
+      Label loop;
+      __ Set(rcx, 0);
+      __ leap(rbx, Operand(rsp, rbx, times_pointer_size, 0));
+      __ bind(&loop);
+      __ movp(kScratchRegister, Operand(rbx, rcx, times_pointer_size, 0));
+      __ movp(Operand(rsp, rcx, times_pointer_size, 0), kScratchRegister);
+      __ incl(rcx);
+      __ cmpl(rcx, rax);
+      __ j(less, &loop);
+    }
+
+    // Copy [[BoundArguments]] to the stack (below the arguments).
+    {
+      Label loop;
+      __ movp(rcx, FieldOperand(rdi, JSBoundFunction::kBoundArgumentsOffset));
+      __ SmiToInteger32(rbx, FieldOperand(rcx, FixedArray::kLengthOffset));
+      __ bind(&loop);
+      __ decl(rbx);
+      __ movp(kScratchRegister, FieldOperand(rcx, rbx, times_pointer_size,
+                                             FixedArray::kHeaderSize));
+      __ movp(Operand(rsp, rax, times_pointer_size, 0), kScratchRegister);
+      __ leal(rax, Operand(rax, 1));
+      __ j(greater, &loop);
+    }
+
+    // Adjust effective number of arguments (rax contains the number of
+    // arguments from the call plus return address plus the number of
+    // [[BoundArguments]]), so we need to subtract one for the return address.
+    __ decl(rax);
+  }
+  __ bind(&no_bound_arguments);
+}
+
+}  // namespace
+
+
+// static
+void Builtins::Generate_CallBoundFunction(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rax : the number of arguments (not including the receiver)
+  //  -- rdi : the function to call (checked to be a JSBoundFunction)
+  // -----------------------------------
+  __ AssertBoundFunction(rdi);
+
+  // Patch the receiver to [[BoundThis]].
+  StackArgumentsAccessor args(rsp, rax);
+  __ movp(rbx, FieldOperand(rdi, JSBoundFunction::kBoundThisOffset));
+  __ movp(args.GetReceiverOperand(), rbx);
+
+  // Push the [[BoundArguments]] onto the stack.
+  Generate_PushBoundArguments(masm);
+
+  // Call the [[BoundTargetFunction]] via the Call builtin.
+  __ movp(rdi, FieldOperand(rdi, JSBoundFunction::kBoundTargetFunctionOffset));
+  __ Load(rcx,
+          ExternalReference(Builtins::kCall_ReceiverIsAny, masm->isolate()));
+  __ leap(rcx, FieldOperand(rcx, Code::kHeaderSize));
+  __ jmp(rcx);
+}
+
+
 // static
 void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode) {
   // ----------- S t a t e -------------
@@ -1987,6 +2097,9 @@ void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode) {
   __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rcx);
   __ j(equal, masm->isolate()->builtins()->CallFunction(mode),
        RelocInfo::CODE_TARGET);
+  __ CmpInstanceType(rcx, JS_BOUND_FUNCTION_TYPE);
+  __ j(equal, masm->isolate()->builtins()->CallBoundFunction(),
+       RelocInfo::CODE_TARGET);
   __ CmpInstanceType(rcx, JS_PROXY_TYPE);
   __ j(not_equal, &non_function);
 
@@ -2049,6 +2162,36 @@ void Builtins::Generate_ConstructFunction(MacroAssembler* masm) {
 
 
 // static
+void Builtins::Generate_ConstructBoundFunction(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rax : the number of arguments (not including the receiver)
+  //  -- rdx : the new target (checked to be a constructor)
+  //  -- rdi : the constructor to call (checked to be a JSBoundFunction)
+  // -----------------------------------
+  __ AssertBoundFunction(rdi);
+
+  // Push the [[BoundArguments]] onto the stack.
+  Generate_PushBoundArguments(masm);
+
+  // Patch new.target to [[BoundTargetFunction]] if new.target equals target.
+  {
+    Label done;
+    __ cmpp(rdi, rdx);
+    __ j(not_equal, &done, Label::kNear);
+    __ movp(rdx,
+            FieldOperand(rdi, JSBoundFunction::kBoundTargetFunctionOffset));
+    __ bind(&done);
+  }
+
+  // Construct the [[BoundTargetFunction]] via the Construct builtin.
+  __ movp(rdi, FieldOperand(rdi, JSBoundFunction::kBoundTargetFunctionOffset));
+  __ Load(rcx, ExternalReference(Builtins::kConstruct, masm->isolate()));
+  __ leap(rcx, FieldOperand(rcx, Code::kHeaderSize));
+  __ jmp(rcx);
+}
+
+
+// static
 void Builtins::Generate_ConstructProxy(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax : the number of arguments (not including the receiver)
@@ -2093,6 +2236,12 @@ void Builtins::Generate_Construct(MacroAssembler* masm) {
            Immediate(1 << Map::kIsConstructor));
   __ j(zero, &non_constructor, Label::kNear);
 
+  // Only dispatch to bound functions after checking whether they are
+  // constructors.
+  __ CmpInstanceType(rcx, JS_BOUND_FUNCTION_TYPE);
+  __ j(equal, masm->isolate()->builtins()->ConstructBoundFunction(),
+       RelocInfo::CODE_TARGET);
+
   // Only dispatch to proxies after checking whether they are constructors.
   __ CmpInstanceType(rcx, JS_PROXY_TYPE);
   __ j(equal, masm->isolate()->builtins()->ConstructProxy(),