Modify growth policy for table of canonical types in each class.

runtime/vm/object.cc

 // 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 4245 matching lines @@
   if ((bound_error != NULL) && !bound_error->IsNull()) {
     return result.raw();
   }
   // Instantiation did not result in bound error. Canonicalize type arguments.
   result = result.Canonicalize();
   // Add instantiator and result to instantiations array.
   intptr_t length = prior_instantiations.Length();
   if ((index + 2) >= length) {
     // Grow the instantiations array.
     // The initial array is Object::zero_array() of length 1.
-    length = (length == 1) ? 3 : length + 4;
+    length = (length == 1) ? 3 : ((length - 1) * 2 + 1);

[Ivan Posva, 2014/02/21 22:26:56]

How about not allowing unbounded exponential growth?

length = (length > 64) ?
  (length + 64) :
  ((length == 1) ? 3 : ((length - 1) * 2 + 1));

[regis, 2014/02/21 23:08:47]

Done.

     prior_instantiations =
         Array::Grow(prior_instantiations, length, Heap::kOld);
     set_instantiations(prior_instantiations);
     ASSERT((index + 2) < length);
   }
   prior_instantiations.SetAt(index, instantiator_type_arguments);
   prior_instantiations.SetAt(index + 1, result);
   prior_instantiations.SetAt(index + 2,
                              Smi::Handle(Smi::New(StubCode::kNoInstantiator)));
   return result.raw();
@@ skipping 8608 matching lines @@
     }
     ASSERT(this->Equals(type));
     return type.raw();
   }
 
   Array& canonical_types = Array::Handle(isolate);
   canonical_types ^= cls.canonical_types();
   if (canonical_types.IsNull()) {
     canonical_types = empty_array().raw();
   }
-  const intptr_t canonical_types_len = canonical_types.Length();
+  const intptr_t length = canonical_types.Length();
   // Linear search to see whether this type is already present in the
   // list of canonicalized types.
   // TODO(asiva): Try to re-factor this lookup code to make sharing
   // easy between the 4 versions of this loop.
   intptr_t index = 0;
-  while (index < canonical_types_len) {
+  while (index < length) {
     type ^= canonical_types.At(index);
     if (type.IsNull()) {
       break;
     }
     ASSERT(type.IsFinalized());
     if (this->Equals(type)) {
       return type.raw();
     }
     index++;
   }
   // Canonicalize the type arguments.
   TypeArguments& type_args = TypeArguments::Handle(isolate, arguments());
   // In case the type is first canonicalized at runtime, its type argument
   // vector may be longer than necessary. This is not an issue.
   ASSERT(type_args.IsNull() || (type_args.Length() >= cls.NumTypeArguments()));
   type_args = type_args.Canonicalize(trail);
   set_arguments(type_args);
   // The type needs to be added to the list. Grow the list if it is full.
-  if (index == canonical_types_len) {
-    const intptr_t kLengthIncrement = 2;  // Raw and parameterized.
-    const intptr_t new_length = canonical_types.Length() + kLengthIncrement;
+  if (index == length) {
+    const intptr_t new_length = (length == 0) ? 1 : (length * 2);

[Ivan Posva, 2014/02/21 22:26:56]

ditto

[regis, 2014/02/21 23:08:47]

Done.

     const Array& new_canonical_types = Array::Handle(
         isolate, Array::Grow(canonical_types, new_length, Heap::kOld));
     cls.set_canonical_types(new_canonical_types);
     new_canonical_types.SetAt(index, *this);
   } else {
     canonical_types.SetAt(index, *this);
   }
 #ifdef DEBUG
   if ((index == 0) && cls.IsCanonicalSignatureClass()) {
     // Verify that the first canonical type is the signature type by checking
@@ skipping 4520 matching lines @@
   return "_MirrorReference";
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   Instance::PrintToJSONStream(stream, ref);
 }
 
 
 }  // namespace dart