Use distinct maps for oddballs with special handling in the type system.

src/objects-debug.cc

Index: src/objects-debug.cc
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index ba9ff65be0c4883b97685076fdeef82e9f528671..87383c7257784d276c1d0d34599f7fe9383b6931 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -596,10 +596,11 @@ void JSBuiltinsObject::JSBuiltinsObjectVerify() {
 
 void Oddball::OddballVerify() {
   CHECK(IsOddball());
+  Heap* heap = GetHeap();
   VerifyHeapPointer(to_string());
   Object* number = to_number();
   if (number->IsHeapObject()) {
-    CHECK(number == HeapObject::cast(number)->GetHeap()->nan_value());
+    CHECK(number == heap->nan_value());
   } else {
     CHECK(number->IsSmi());
     int value = Smi::cast(number)->value();
@@ -608,6 +609,26 @@ void Oddball::OddballVerify() {
     CHECK_LE(value, 1);
     CHECK(value >= kLeastHiddenOddballNumber);
   }
+  if (map() == heap->undefined_map()) {
+    CHECK(this == heap->undefined_value());
+  } else if (map() == heap->the_hole_map()) {
+    CHECK(this == heap->the_hole_value());
+  } else if (map() == heap->null_map()) {
+    CHECK(this == heap->null_value());
+  } else if (map() == heap->boolean_map()) {
+    CHECK(this == heap->true_value() ||
+          this == heap->false_value());
+  } else if (map() == heap->uninitialized_map()) {
+    CHECK(this == heap->uninitialized_value());
+  } else if (map() == heap->no_interceptor_result_sentinel_map()) {
+    CHECK(this == heap->no_interceptor_result_sentinel());
+  } else if (map() == heap->arguments_marker_map()) {
+    CHECK(this == heap->arguments_marker());
+  } else if (map() == heap->termination_exception_map()) {
+    CHECK(this == heap->termination_exception());
+  } else {
+    UNREACHABLE();
+  }
 }