[WIP] Initial CallFunctionCallback builtin.

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index a80feeb778365762451f037f20716c1bc5945abb..7b5dd7816b9e773854fd8e04597d4d0f075b176d 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -3768,6 +3768,35 @@ void MacroAssembler::AssertUndefinedOrAllocationSite(Register object) {
   }
 }
 
+void MacroAssembler::AssertApiCallResult(Register object) {
+  if (emit_debug_code()) {
+    Label done_checking;
+    Push(object);
+
+    // Check for Smis.
+    JumpIfSmi(object, &done_checking, Label::kNear);
+
+    // Check for valid Oddballs.
+    JumpIfRoot(object, Heap::kTrueValueRootIndex, &done_checking, Label::kNear);
+    JumpIfRoot(object, Heap::kFalseValueRootIndex, &done_checking,
+               Label::kNear);
+    JumpIfRoot(object, Heap::kNullValueRootIndex, &done_checking, Label::kNear);
+    JumpIfRoot(object, Heap::kUndefinedValueRootIndex, &done_checking,
+               Label::kNear);
+
+    // Check for other primitives (String, Symbol and HeapNumber).
+    STATIC_ASSERT(LAST_PRIMITIVE_TYPE == ODDBALL_TYPE);
+    CmpObjectType(object, LAST_PRIMITIVE_TYPE, object);
+    j(below, &done_checking, Label::kNear);
+
+    // Check for JSReceivers.
+    CmpInstanceType(object, FIRST_JS_RECEIVER_TYPE);
+    Check(above_equal, kAPICallReturnedInvalidObject);
+
+    bind(&done_checking);
+    Pop(object);
+  }
+}
 
 Condition MacroAssembler::IsObjectStringType(Register heap_object,
                                              Register map,