Add an IC for CompareNil operations

src/code-stubs.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 389 matching lines @@
       ASSERT(*known_map_ != NULL);
       GenerateKnownObjects(masm);
       break;
     case CompareIC::GENERIC:
       GenerateGeneric(masm);
       break;
   }
 }
 
 
+CompareNilICStub::Types CompareNilICStub::GetPatchedICFlags(
+    Code* ic,
+    EqualityKind kind,
+    NilValue nil,
+    Handle<Object> object,
+    bool* already_monomorphic) {
+  Code::ExtraICState extra_state = ic->extra_ic_state();
+  CompareNilICStub::Types types =
+      CompareNilICStub::TypesFromExtraICState(extra_state);
+  ASSERT(types != CompareNilICStub::kFullCompare);
+  *already_monomorphic =
+      (types & CompareNilICStub::kCompareAgainstMonomorphicMap) != 0;
+  if (kind == kStrictEquality) {
+    if (nil == kNullValue) {
+      return CompareNilICStub::kCompareAgainstNull;
+    } else {
+      return CompareNilICStub::kCompareAgainstUndefined;
+    }
+  } else {
+    if (object->IsNull()) {
+      types = static_cast<CompareNilICStub::Types>(
+          types | CompareNilICStub::kCompareAgainstNull);
+    } else if (object->IsUndefined()) {
+      types = static_cast<CompareNilICStub::Types>(
+          types | CompareNilICStub::kCompareAgainstUndefined);
+    } else {
+      if (object->IsUndetectableObject() || !object->IsHeapObject()) {
+        types = CompareNilICStub::kFullCompare;
+      } else {
+        if ((types & CompareNilICStub::kCompareAgainstMonomorphicMap) != 0) {
+          ASSERT_EQ(Code::COMPARE_NIL_IC, ic->kind());
+          Map* monomorphic_map = ic->FindFirstMap();
+          if (monomorphic_map != Handle<HeapObject>::cast(object)->map()) {
+            types = CompareNilICStub::kFullCompare;
+          }
+        } else {
+          types = static_cast<CompareNilICStub::Types>(
+            types | CompareNilICStub::kCompareAgainstMonomorphicMap);
+        }
+      }
+    }
+  }
+  return types;
+}
+
+
 void InstanceofStub::PrintName(StringStream* stream) {
   const char* args = "";
   if (HasArgsInRegisters()) {
     args = "_REGS";
   }
 
   const char* inline_check = "";
   if (HasCallSiteInlineCheck()) {
     inline_check = "_INLINE";
   }
@@ skipping 231 matching lines @@
   // already active, as the hooks won't stack.
   if (entry_hook != 0 && entry_hook_ != 0)
     return false;
 
   entry_hook_ = entry_hook;
   return true;
 }
 
 
 } }  // namespace v8::internal