[v8-dev] Make Value::IsUndefined and Value::IsNull inlineable. (issue 10091035)

Tue, 17 Apr 2012 05:27:05 -0700 

Reviewers: danno,

Description:
Make Value::IsUndefined and Value::IsNull inlineable.

[email protected]
TEST=cctest/test-api


Please review this at https://chromiumcodereview.appspot.com/10091035/

SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge

Affected files:
  M include/v8.h
  M src/api.cc
  M src/objects.h


Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 0f05230596e19496a7a98515dea6fa918b7a6a31..98af428616a8eef5fabe1d6a2d0d308381e7b5e6 100644 
--- a/include/v8.h
+++ b/include/v8.h
@@ -863,13 +863,13 @@ class Value : public Data {
    * Returns true if this value is the undefined value.  See ECMA-262
    * 4.3.10.
    */
-  V8EXPORT bool IsUndefined() const;
+  inline bool IsUndefined() const;

   /**
    * Returns true if this value is the null value.  See ECMA-262
    * 4.3.11.
    */
-  V8EXPORT bool IsNull() const;
+  inline bool IsNull() const;

    /**
    * Returns true if this value is true.
@@ -983,7 +983,11 @@ class Value : public Data {
   V8EXPORT bool StrictEquals(Handle<Value> that) const;

  private:
+  inline bool QuickIsUndefined() const;
+  inline bool QuickIsNull() const;
   inline bool QuickIsString() const;
+  V8EXPORT bool FullIsUndefined() const;
+  V8EXPORT bool FullIsNull() const;
   V8EXPORT bool FullIsString() const;
 };

@@ -3891,6 +3895,7 @@ class Internals {
   static const int kStringResourceOffset =
       InternalConstants<kApiPointerSize>::kStringResourceOffset;

+  static const int kOddballKindOffset = 3 * kApiPointerSize;
   static const int kForeignAddressOffset = kApiPointerSize;
   static const int kJSObjectHeaderSize = 3 * kApiPointerSize;
   static const int kFullStringRepresentationMask = 0x07;
@@ -3898,8 +3903,12 @@ class Internals {

   static const int kJSObjectType = 0xaa;
   static const int kFirstNonstringType = 0x80;
+  static const int kOddballType = 0x82;
   static const int kForeignType = 0x85;

+  static const int kUndefinedOddballKind = 5;
+  static const int kNullOddballKind = 3;
+
   static inline bool HasHeapObjectTag(internal::Object* value) {
     return ((reinterpret_cast<intptr_t>(value) & kHeapObjectTagMask) ==
             kHeapObjectTag);
@@ -3919,6 +3928,11 @@ class Internals {
     return ReadField<uint8_t>(map, kMapInstanceTypeOffset);
   }

+  static inline int GetOddballKind(internal::Object* obj) {
+    typedef internal::Object O;
+    return SmiValue(ReadField<O*>(obj, kOddballKindOffset));
+  }
+
   static inline void* GetExternalPointerFromSmi(internal::Object* value) {
     const uintptr_t address = reinterpret_cast<uintptr_t>(value);
     return reinterpret_cast<void*>(address >> kPointerToSmiShift);
@@ -4200,6 +4214,42 @@ String::ExternalStringResource* String::GetExternalStringResource() const { 
 }


+bool Value::IsUndefined() const {
+#ifdef V8_ENABLE_CHECKS
+  return FullIsUndefined();
+#else
+  return QuickIsUndefined();
+#endif
+}
+
+bool Value::QuickIsUndefined() const {
+  typedef internal::Object O;
+  typedef internal::Internals I;
+  O* obj = *reinterpret_cast<O**>(const_cast<Value*>(this));
+  if (!I::HasHeapObjectTag(obj)) return false;
+  if (I::GetInstanceType(obj) != I::kOddballType) return false;
+  return (I::GetOddballKind(obj) == I::kUndefinedOddballKind);
+}
+
+
+bool Value::IsNull() const {
+#ifdef V8_ENABLE_CHECKS
+  return FullIsNull();
+#else
+  return QuickIsNull();
+#endif
+}
+
+bool Value::QuickIsNull() const {
+  typedef internal::Object O;
+  typedef internal::Internals I;
+  O* obj = *reinterpret_cast<O**>(const_cast<Value*>(this));
+  if (!I::HasHeapObjectTag(obj)) return false;
+  if (I::GetInstanceType(obj) != I::kOddballType) return false;
+  return (I::GetOddballKind(obj) == I::kNullOddballKind);
+}
+
+
 bool Value::IsString() const {
 #ifdef V8_ENABLE_CHECKS
   return FullIsString();
Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index c7252ba3ffd08ebf0f857ebe90195da9fde80980..3826a1c97b25cab93b0497e1221b648013b582f8 100644 
--- a/src/api.cc
+++ b/src/api.cc
@@ -2101,17 +2101,21 @@ bool StackFrame::IsConstructor() const {

 // --- D a t a ---

-bool Value::IsUndefined() const {
+bool Value::FullIsUndefined() const {
   if (IsDeadCheck(i::Isolate::Current(), "v8::Value::IsUndefined()")) {
     return false;
   }
-  return Utils::OpenHandle(this)->IsUndefined();
+  bool result = Utils::OpenHandle(this)->IsUndefined();
+  ASSERT_EQ(result, QuickIsUndefined());
+  return result;
 }


-bool Value::IsNull() const {
+bool Value::FullIsNull() const {
if (IsDeadCheck(i::Isolate::Current(), "v8::Value::IsNull()")) return false; 
-  return Utils::OpenHandle(this)->IsNull();
+  bool result = Utils::OpenHandle(this)->IsNull();
+  ASSERT_EQ(result, QuickIsNull());
+  return result;
 }


Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index d682cde0f81cb0a4edd5d86b5903fccfad8f17b3..80d1fd47d02ab60dd015704d7836b20bf9b9189a 100644 
--- a/src/objects.h
+++ b/src/objects.h
@@ -680,6 +680,7 @@ const int kExternalArrayTypeCount =

 STATIC_CHECK(JS_OBJECT_TYPE == Internals::kJSObjectType);
 STATIC_CHECK(FIRST_NONSTRING_TYPE == Internals::kFirstNonstringType);
+STATIC_CHECK(ODDBALL_TYPE == Internals::kOddballType);
 STATIC_CHECK(FOREIGN_TYPE == Internals::kForeignType);


@@ -7636,6 +7637,10 @@ class Oddball: public HeapObject {
                               kToNumberOffset + kPointerSize,
                               kSize> BodyDescriptor;

+  STATIC_CHECK(kKindOffset == Internals::kOddballKindOffset);
+  STATIC_CHECK(kNull == Internals::kNullOddballKind);
+  STATIC_CHECK(kUndefined == Internals::kUndefinedOddballKind);
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(Oddball);
 };


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