Cache lookups at megamorphic call sites in optimized code.

runtime/vm/raw_object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/token.h"
@@ skipping 22 matching lines @@
   V(Code)                                                                      \
   V(Instructions)                                                              \
   V(PcDescriptors)                                                             \
   V(Stackmap)                                                                  \
   V(LocalVarDescriptors)                                                       \
   V(ExceptionHandlers)                                                         \
   V(DeoptInfo)                                                                 \
   V(Context)                                                                   \
   V(ContextScope)                                                              \
   V(ICData)                                                                    \
+  V(MegamorphicCache)                                                          \
   V(SubtypeTestCache)                                                          \
   V(Error)                                                                     \
     V(ApiError)                                                                \
     V(LanguageError)                                                           \
     V(UnhandledException)                                                      \
     V(UnwindError)                                                             \
   V(Instance)                                                                  \
     V(AbstractType)                                                            \
       V(Type)                                                                  \
       V(TypeParameter)                                                         \
@@ skipping 874 matching lines @@
   RawObject** to() {
     return reinterpret_cast<RawObject**>(&ptr()->ic_data_);
   }
   intptr_t deopt_id_;         // Deoptimization id corresponding to this IC.
   intptr_t num_args_tested_;  // Number of arguments tested in IC.
   uint8_t deopt_reason_;      // Last deoptimization reason.
   uint8_t is_closure_call_;   // 0 or 1.
 };
 
 
+class RawMegamorphicCache : public RawObject {
+  RAW_HEAP_OBJECT_IMPLEMENTATION(MegamorphicCache);
+
+  RawObject** from() {
+    return reinterpret_cast<RawObject**>(&ptr()->buckets_);
+  }
+  RawArray* buckets_;
+  RawSmi* mask_;
+  RawObject** to() {
+    return reinterpret_cast<RawObject**>(&ptr()->mask_);
+  }
+
+  intptr_t filled_entry_count_;
+};
+
+
 class RawSubtypeTestCache : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(SubtypeTestCache);
   RawArray* cache_;
 };
 
 
 class RawError : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Error);
 };
 
@@ skipping 690 matching lines @@
          kExternalUint64ArrayCid == kExternalInt8ArrayCid + 7 &&
          kExternalFloat32ArrayCid == kExternalInt8ArrayCid + 8 &&
          kExternalFloat64ArrayCid == kExternalInt8ArrayCid + 9 &&
          kStacktraceCid == kExternalInt8ArrayCid + 10);
   return (index >= kExternalInt8ArrayCid && index <= kExternalFloat64ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_