Speed up the Dart_IsBlah functions by checking the class index. This

vm/dart_api_impl.cc

Index: vm/dart_api_impl.cc
===================================================================
--- vm/dart_api_impl.cc	(revision 7467)
+++ vm/dart_api_impl.cc	(working copy)
@@ -42,19 +42,19 @@
   }
 }
 
-#define RETURN_TYPE_ERROR(isolate, dart_handle, Type)                         \
-  do {                                                                        \
-    const Object& tmp =                                                       \
-        Object::Handle(isolate, Api::UnwrapHandle((dart_handle)));            \
-    if (tmp.IsNull()) {                                                       \
-      return Api::NewError("%s expects argument '%s' to be non-null.",        \
-                           CURRENT_FUNC, #dart_handle);                       \
-    } else if (tmp.IsError()) {                                               \
-      return dart_handle;                                                     \
-    } else {                                                                  \
-      return Api::NewError("%s expects argument '%s' to be of type %s.",      \
-                           CURRENT_FUNC, #dart_handle, #Type);                \
-    }                                                                         \
+#define RETURN_TYPE_ERROR(isolate, dart_handle, Type)                   \
+  do {                                                                  \
+    const Object& tmp =                                                 \
+        Object::Handle(isolate, Api::UnwrapHandle((dart_handle)));      \
+    if (tmp.IsNull()) {                                                 \
+      return Api::NewError("%s expects argument '%s' to be non-null.",  \
+                           CURRENT_FUNC, #dart_handle);                 \
+    } else if (tmp.IsError()) {                                         \
+      return dart_handle;                                               \
+    } else {                                                            \
+      return Api::NewError("%s expects argument '%s' to be of type %s.", \
+                           CURRENT_FUNC, #dart_handle, #Type);          \
+    }                                                                   \
   } while (0)
 
 
@@ -120,15 +120,15 @@
   return *(reinterpret_cast<RawObject**>(object));
 }
 
-#define DEFINE_UNWRAP(Type)                                                   \
-  const Type& Api::Unwrap##Type##Handle(Isolate* iso,                         \
-                                        Dart_Handle dart_handle) {            \
-    const Object& tmp = Object::Handle(iso, Api::UnwrapHandle(dart_handle));  \
-    Type& typed_handle = Type::Handle(iso);                                   \
-    if (tmp.Is##Type()) {                                                     \
-      typed_handle ^= tmp.raw();                                              \
-    }                                                                         \
-    return typed_handle;                                                      \
+#define DEFINE_UNWRAP(Type)                                             \
+  const Type& Api::Unwrap##Type##Handle(Isolate* iso,                   \
+                                        Dart_Handle dart_handle) {      \
+    const Object& tmp = Object::Handle(iso, Api::UnwrapHandle(dart_handle)); \
+    Type& typed_handle = Type::Handle(iso);                             \
+    if (tmp.Is##Type()) {                                               \
+      typed_handle ^= tmp.raw();                                        \
+    }                                                                   \
+    return typed_handle;                                                \
   }
 CLASS_LIST_NO_OBJECT(DEFINE_UNWRAP)
 #undef DEFINE_UNWRAP
@@ -259,10 +259,9 @@
 
 
 DART_EXPORT bool Dart_IsError(Dart_Handle handle) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(handle));
-  return obj.IsError();
+  ASSERT(kError + 5 == kInstance);  // There are 4 subtypes of Error.

[Ivan Posva, 2012/05/09 23:28:16]

This is brittle in case we delete one of the error types and add a new non-error
type before kInstance. Should we just enumerate them here?

[turnidge, 2012/05/10 17:49:38]

I have moved all of these predicates to raw_object.h.  I considered attaching
the functions to the Raw classes (like putting IsErrorClassIndex on RawError)
but it got odd in the case of builtin LIst types (they don't seem to have a
common supertype) so I left them as standalone functions.  I have expanded the
asserts to try to make them less brittle.

+  intptr_t class_index = Api::ClassIndex(handle);
+  return (class_index >= kError && class_index < kInstance);
 }
 
 
@@ -374,9 +373,9 @@
 
 
 DART_EXPORT void _Dart_ReportErrorHandle(const char* file,
-                                           int line,
-                                           const char* handle,
-                                           const char* message) {
+                                         int line,
+                                         const char* handle,
+                                         const char* message) {
   fprintf(stderr, "%s:%d: error handle: '%s':\n    '%s'\n",
           file, line, handle, message);
   OS::Abort();
@@ -1010,10 +1009,8 @@
 
 
 DART_EXPORT bool Dart_IsNull(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsNull();
+  ASSERT(kNullClassIndex + 1 == kDynamicClassIndex);  // No subtypes.
+  return Api::ClassIndex(object) == kNullClassIndex;
 }
 
 
@@ -1083,10 +1080,9 @@
 
 // TODO(iposva): The argument should be an instance.
 DART_EXPORT bool Dart_IsNumber(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsNumber();
+  ASSERT(kNumber + 6 == kString);  // There are 5 subtypes of Number.

[Ivan Posva, 2012/05/09 23:28:16]

ditto.

+  intptr_t class_index = Api::ClassIndex(object);
+  return (class_index >= kNumber && class_index < kString);
 }
 
 
@@ -1094,24 +1090,19 @@
 
 
 DART_EXPORT bool Dart_IsInteger(Dart_Handle object) {
-  // Fast path for Smis.
-  if (Api::IsSmi(object)) {
-    return true;
-  }
-
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsInteger();
+  ASSERT(kInteger + 4 == kDouble);  // There are 3 subtypes of Integer.

[Ivan Posva, 2012/05/09 23:28:16]

ditto.

+  intptr_t class_index = Api::ClassIndex(object);
+  return (class_index >= kInteger && class_index < kDouble);
 }
 
 
 DART_EXPORT Dart_Handle Dart_IntegerFitsIntoInt64(Dart_Handle integer,
                                                   bool* fits) {
-  // Fast path for Smis.
+  // Fast path for Smis and Mints.
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
-  if (Api::IsSmi(integer)) {
+  intptr_t class_index = Api::ClassIndex(integer);
+  if (class_index == kSmi || class_index == kMint) {
     *fits = true;
     return Api::Success(isolate);
   }
@@ -1121,17 +1112,13 @@
   if (int_obj.IsNull()) {
     RETURN_TYPE_ERROR(isolate, integer, Integer);
   }
-  if (int_obj.IsSmi() || int_obj.IsMint()) {
-    *fits = true;
-  } else {
-    ASSERT(int_obj.IsBigint());
+  ASSERT(int_obj.IsBigint());
 #if defined(DEBUG)
-    Bigint& bigint = Bigint::Handle(isolate);
-    bigint ^= int_obj.raw();
-    ASSERT(!BigintOperations::FitsIntoMint(bigint));
+  Bigint& bigint = Bigint::Handle(isolate);
+  bigint ^= int_obj.raw();
+  ASSERT(!BigintOperations::FitsIntoMint(bigint));
 #endif
-    *fits = false;
-  }
+  *fits = false;
   return Api::Success(isolate);
 }
 
@@ -1298,10 +1285,8 @@
 
 
 DART_EXPORT bool Dart_IsBoolean(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsBool();
+  ASSERT(kBool + 1 == kArray);  // No subtypes.

[turnidge, 2012/05/10 17:49:38]

I dropped the asserts for types with no subtypes.  I felt that they were overly
paranoid -- let me know if you disagree.

+  return Api::ClassIndex(object) == kBool;
 }
 
 
@@ -1329,10 +1314,8 @@
 
 
 DART_EXPORT bool Dart_IsDouble(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsDouble();
+  ASSERT(kDouble + 1 == kString);  // No subtypes.
+  return Api::ClassIndex(object) == kDouble;
 }
 
 
@@ -1360,27 +1343,25 @@
 
 
 DART_EXPORT bool Dart_IsString(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsString();
+  ASSERT(kString + 7 == kBool);  // There are 6 subtypes of String.

[Ivan Posva, 2012/05/09 23:28:16]

ditto.

+  intptr_t class_index = Api::ClassIndex(object);
+  return (class_index >= kString && class_index < kBool);
 }
 
 
 DART_EXPORT bool Dart_IsString8(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsOneByteString() || obj.IsExternalOneByteString();
+  intptr_t class_index = Api::ClassIndex(object);
+  return (class_index == kOneByteString ||
+          class_index == kExternalOneByteString);
 }
 
 
 DART_EXPORT bool Dart_IsString16(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return (obj.IsOneByteString() || obj.IsExternalOneByteString() ||
-          obj.IsTwoByteString() || obj.IsExternalTwoByteString());
+  intptr_t class_index = Api::ClassIndex(object);
+  return (class_index == kOneByteString ||
+          class_index == kTwoByteString ||
+          class_index == kExternalOneByteString ||
+          class_index == kExternalTwoByteString);
 }
 
 
@@ -1430,13 +1411,10 @@
 
 
 DART_EXPORT bool Dart_IsExternalString(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const String& str = Api::UnwrapStringHandle(isolate, object);
-  if (str.IsNull()) {
-    return false;
-  }
-  return str.IsExternal();
+  intptr_t class_index = Api::ClassIndex(object);
+  return (class_index == kExternalOneByteString ||
+          class_index == kExternalTwoByteString ||
+          class_index == kExternalFourByteString);
 }
 
 
@@ -1663,11 +1641,17 @@
 
 
 DART_EXPORT bool Dart_IsList(Dart_Handle object) {
+  ASSERT(kArray + 2 == kGrowableObjectArray);  // There is 1 subtype of Array.

[Ivan Posva, 2012/05/09 23:28:16]

ditto.

+  ASSERT(kGrowableObjectArray + 1 == kByteArray);  // No subtypes.
+  intptr_t class_index = Api::ClassIndex(object);
+  if (class_index >= kArray && class_index < kByteArray) {
+    return true;
+  }
+
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return (obj.IsArray() || obj.IsGrowableObjectArray() ||
-          (GetListInstance(isolate, obj) != Instance::null()));
+  return GetListInstance(isolate, obj) != Instance::null();
 }
 
 
@@ -2012,10 +1996,9 @@
 
 
 DART_EXPORT bool Dart_IsByteArray(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsByteArray();
+  ASSERT(kByteArray + 21 == kClosure);  // There are 20 subtypes of ByteArray

[Ivan Posva, 2012/05/09 23:28:16]

ditto.

+  intptr_t class_index = Api::ClassIndex(object);
+  return (class_index >= kByteArray && class_index <= kClosure);
 }
 
 
@@ -2243,6 +2226,8 @@
 
 
 DART_EXPORT bool Dart_IsClosure(Dart_Handle object) {
+  // We can't use a fast class index check here because there are many
+  // different signature classes for closures.
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
@@ -3126,10 +3111,8 @@
 
 
 DART_EXPORT bool Dart_IsLibrary(Dart_Handle object) {
-  Isolate* isolate = Isolate::Current();
-  DARTSCOPE(isolate);
-  const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(object));
-  return obj.IsLibrary();
+  ASSERT(kLibrary + 1 == kLibraryPrefix);  // No subtypes.
+  return Api::ClassIndex(object) == kLibrary;
 }