Stack maps: Handle special cases using flags.

Keep the BitTable decoder simple (1+NumColumns varints).
Move special case handling up to CodeInfo (empty/dedup).

This speeds up CodeInfo by 5%, and maps startup by 0.05%.
Change in size is negligible (the bits mostly just move).

Test: test.py -b --host --64 --optimizing
Change-Id: Ib6abe52f04384de9ffd7cfba04a3124b62f713ff

1 files changed, 19 insertions, 5 deletions

diff --git a/compiler/optimizing/stack_map_stream.h b/compiler/optimizing/stack_map_stream.h
index 20dd32e308..33c624a36c 100644
--- a/compiler/optimizing/stack_map_stream.h
+++ b/compiler/optimizing/stack_map_stream.h
@@ -40,10 +40,10 @@ class StackMapStream : public DeletableArenaObject<kArenaAllocStackMapStream> {
       : allocator_(allocator),
         instruction_set_(instruction_set),
         stack_maps_(allocator),
-        inline_infos_(allocator),
-        method_infos_(allocator),
         register_masks_(allocator),
         stack_masks_(allocator),
+        inline_infos_(allocator),
+        method_infos_(allocator),
         dex_register_masks_(allocator),
         dex_register_maps_(allocator),
         dex_register_catalog_(allocator),
@@ -97,18 +97,32 @@ class StackMapStream : public DeletableArenaObject<kArenaAllocStackMapStream> {
 
   void CreateDexRegisterMap();
 
+  // Invokes the callback with pointer of each BitTableBuilder field.
+  template<typename Callback>
+  void ForEachBitTable(Callback callback) {
+    size_t index = 0;
+    callback(index++, &stack_maps_);
+    callback(index++, &register_masks_);
+    callback(index++, &stack_masks_);
+    callback(index++, &inline_infos_);
+    callback(index++, &method_infos_);
+    callback(index++, &dex_register_masks_);
+    callback(index++, &dex_register_maps_);
+    callback(index++, &dex_register_catalog_);
+    CHECK_EQ(index, CodeInfo::kNumBitTables);
+  }
+
   ScopedArenaAllocator* allocator_;
   const InstructionSet instruction_set_;
-  uint32_t flags_ = 0;
   uint32_t packed_frame_size_ = 0;
   uint32_t core_spill_mask_ = 0;
   uint32_t fp_spill_mask_ = 0;
   uint32_t num_dex_registers_ = 0;
   BitTableBuilder<StackMap> stack_maps_;
-  BitTableBuilder<InlineInfo> inline_infos_;
-  BitTableBuilder<MethodInfo> method_infos_;
   BitTableBuilder<RegisterMask> register_masks_;
   BitmapTableBuilder stack_masks_;
+  BitTableBuilder<InlineInfo> inline_infos_;
+  BitTableBuilder<MethodInfo> method_infos_;
   BitmapTableBuilder dex_register_masks_;
   BitTableBuilder<DexRegisterMapInfo> dex_register_maps_;
   BitTableBuilder<DexRegisterInfo> dex_register_catalog_;