Give a length field to stack bitmaps.

runtime/vm/code_descriptors.cc

Index: runtime/vm/code_descriptors.cc
diff --git a/runtime/vm/code_descriptors.cc b/runtime/vm/code_descriptors.cc
index 027e8b65d284d2d9a4e3da584333b76bb43946d0..3885f955bd8c60460cace3acc52bd611ed56cc0e 100644
--- a/runtime/vm/code_descriptors.cc
+++ b/runtime/vm/code_descriptors.cc
@@ -54,7 +54,8 @@ RawPcDescriptors* DescriptorList::FinalizePcDescriptors(uword entry_point) {
 
 void StackmapTableBuilder::AddEntry(intptr_t pc_offset,
                                     BitmapBuilder* bitmap) {
-  stack_map_ = Stackmap::New(pc_offset, entry_length_, bitmap);
+  bitmap->SetLength(entry_length_);

[Kevin Millikin (Google), 2012/08/21 13:24:07]

Long-term, we will not set the length here but earlier (in the register
allocator?) when we finish the bitmap.

[Vyacheslav Egorov (Google), 2012/08/22 11:49:40]

Add a TODO

+  stack_map_ = Stackmap::New(pc_offset, bitmap);
   list_.Add(stack_map_);
 }