- Preallocate non-named ArgumentsDescriptors with a small amount of parameters.

runtime/vm/dart_entry.h

 // Copyright (c) 2011, 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_DART_ENTRY_H_
 #define VM_DART_ENTRY_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 
@@ skipping 39 matching lines @@
   // Allocate and return an arguments descriptor.  The first
   // (count - optional_arguments_names.Length()) arguments are
   // positional and the remaining ones are named optional arguments.
   static RawArray* New(intptr_t count,
                        const Array& optional_arguments_names);
 
   // Allocate and return an arguments descriptor that has no optional
   // arguments. All arguments are positional.
   static RawArray* New(intptr_t count);
 
+  // Initialize the preallocated fixed length arguments descriptors cache.
+  static void InitOnce();
+
  private:
   // Absolute indexes into the array.
   enum {
     kCountIndex,
     kPositionalCountIndex,
     kFirstNamedEntryIndex,
   };
 
   // Relative indexes into each named argument entry.
   enum {
     kNameOffset,
     kPositionOffset,
     kNamedEntrySize,
   };
 
+  enum {
+    kCachedDescriptorCount = 32
+  };
+
   static intptr_t LengthFor(intptr_t count) {
     // Add 1 for the terminating null.
     return kFirstNamedEntryIndex + (kNamedEntrySize * count) + 1;
   }
 
+  static RawArray* NewNonCached(intptr_t count, bool canonicalize = true);
+
   const Array& array_;
 
+  // A cache of VM heap allocated arguments descriptors.
+  static RawArray* cached_args_descriptors_[kCachedDescriptorCount];
+
   DISALLOW_COPY_AND_ASSIGN(ArgumentsDescriptor);
 };
 
 
 // DartEntry abstracts functionality needed to resolve dart functions
 // and invoke them from C++.
 class DartEntry : public AllStatic {
  public:
   // On success, returns a RawInstance.  On failure, a RawError.
   typedef RawObject* (*invokestub)(uword entry_point,
@@ skipping 82 matching lines @@
 
   // Gets the _id field of a SendPort/ReceivePort.
   //
   // Returns the value of _id on success, a RawError on failure.
   static RawObject* PortGetId(const Instance& port);
 };
 
 }  // namespace dart
 
 #endif  // VM_DART_ENTRY_H_