Reduce space used for stackmaps.

runtime/vm/code_descriptors.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_CODE_DESCRIPTORS_H_
 #define VM_CODE_DESCRIPTORS_H_
 
 #include "vm/globals.h"
 #include "vm/growable_array.h"
 #include "vm/object.h"
@@ skipping 47 matching lines @@
   RawPcDescriptors* FinalizePcDescriptors(uword entry_point);
 
  private:
   GrowableArray<struct PcDesc> list_;
   DISALLOW_COPY_AND_ASSIGN(DescriptorList);
 };
 
 
 class StackmapTableBuilder : public ZoneAllocated {
  public:
-  StackmapTableBuilder() :
+  explicit StackmapTableBuilder(intptr_t entry_length_in_bits) :

[Vyacheslav Egorov (Google), 2012/08/15 14:17:37]

why : is left on this line?

[Kevin Millikin (Google), 2012/08/15 14:41:31]

For historical reasons.

+      entry_length_in_bits_(entry_length_in_bits),
       stack_map_(Stackmap::ZoneHandle()),
       list_(GrowableObjectArray::ZoneHandle(
           GrowableObjectArray::New(Heap::kOld))) { }
   ~StackmapTableBuilder() { }
 
   void AddEntry(intptr_t pc_offset, BitmapBuilder* bitmap);
 
   bool Verify();
 
   RawArray* FinalizeStackmaps(const Code& code);
 
  private:
   intptr_t Length() const { return list_.Length(); }
-  RawStackmap* Map(int index) const;
+  RawStackmap* MapAt(int index) const;
 
+  // All the stackmaps in a function have the same length.
+  intptr_t entry_length_in_bits_;

[srdjan, 2012/08/15 22:17:08]

const

   Stackmap& stack_map_;
   GrowableObjectArray& list_;
   DISALLOW_COPY_AND_ASSIGN(StackmapTableBuilder);
 };
 
 
 class ExceptionHandlerList : public ZoneAllocated {
  public:
   struct HandlerDesc {
     intptr_t try_index;  // Try block index handled by the handler.
@@ skipping 34 matching lines @@
   }
 
  private:
   GrowableArray<struct HandlerDesc> list_;
   DISALLOW_COPY_AND_ASSIGN(ExceptionHandlerList);
 };
 
 }  // namespace dart
 
 #endif  // VM_CODE_DESCRIPTORS_H_