Eliminate 99% of allocated ExceptionHandler objects

runtime/vm/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_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 380 matching lines @@
   static const PcDescriptors& empty_descriptors() {
     ASSERT(empty_descriptors_ != NULL);
     return *empty_descriptors_;
   }
 
   static const LocalVarDescriptors& empty_var_descriptors() {
     ASSERT(empty_var_descriptors_ != NULL);
     return *empty_var_descriptors_;
   }
 
+  static const ExceptionHandlers& empty_exception_handlers() {
+    ASSERT(empty_exception_handlers_ != NULL);
+    return *empty_exception_handlers_;
+  }
+
   // The sentinel is a value that cannot be produced by Dart code.
   // It can be used to mark special values, for example to distinguish
   // "uninitialized" fields.
   static const Instance& sentinel() {
     ASSERT(sentinel_ != NULL);
     return *sentinel_;
   }
   // Value marking that we are transitioning from sentinel, e.g., computing
   // a field value. Used to detect circular initialization.
   static const Instance& transition_sentinel() {
@@ skipping 258 matching lines @@
   // objects that are shared between the different isolates.
   static Object* null_object_;
   static Array* null_array_;
   static String* null_string_;
   static Instance* null_instance_;
   static TypeArguments* null_type_arguments_;
   static Array* empty_array_;
   static Array* zero_array_;
   static PcDescriptors* empty_descriptors_;
   static LocalVarDescriptors* empty_var_descriptors_;
+  static ExceptionHandlers* empty_exception_handlers_;
   static Instance* sentinel_;
   static Instance* transition_sentinel_;
   static Instance* unknown_constant_;
   static Instance* non_constant_;
   static Bool* bool_true_;
   static Bool* bool_false_;
   static Smi* smi_illegal_cid_;
   static LanguageError* snapshot_writer_error_;
   static LanguageError* branch_offset_error_;
 
@@ skipping 2613 matching lines @@
   void SetBit(intptr_t bit_index, bool value) const;
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(Stackmap, Object);
   friend class BitmapBuilder;
   friend class Class;
 };
 
 
 class ExceptionHandlers : public Object {
  public:
-  intptr_t Length() const;
+  intptr_t num_entries() const;
 
   void GetHandlerInfo(intptr_t try_index,
                       RawExceptionHandlers::HandlerInfo* info) const;
 
   intptr_t HandlerPC(intptr_t try_index) const;
   intptr_t OuterTryIndex(intptr_t try_index) const;
   bool NeedsStacktrace(intptr_t try_index) const;
 
   void SetHandlerInfo(intptr_t try_index,
                       intptr_t outer_try_index,
@@ skipping 24 matching lines @@
  private:
   // Pick somewhat arbitrary maximum number of exception handlers
   // for a function. This value is used to catch potentially
   // malicious code.
   static const intptr_t kMaxHandlers = 1024 * 1024;
 
   void set_handled_types_data(const Array& value) const;
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(ExceptionHandlers, Object);
   friend class Class;
+  friend class Object;
 };
 
 
 // Holds deopt information at one deoptimization point. The information consists
 // of two parts:
 //  - first a prefix consiting of kMaterializeObject instructions describing
 //    objects which had their allocation removed as part of AllocationSinking
 //    pass and have to be materialized;
 //  - followed by a list of DeoptInstr objects, specifying transformation
 //    information for each slot in unoptimized frame(s).
@@ skipping 4085 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_