Optimize register mask and stack mask in stack maps.

Use BitTable to store the masks as well and move the
deduplication responsibility to the BitTable builders.

Don't generate entries for masks which are all zeros.
This saves 0.2% of .oat file size on both Arm64 and Arm.

Encode registers as (value+shift) due to tailing zeros.
This saves 1.0% of .oat file size on Arm64 and 0.2% on Arm.

Test: test-art-host-gtest
Change-Id: I636b7edd49e10e8afc9f2aa385b5980f7ee0e1f1

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/optimizing/stack_map_test.cc b/compiler/optimizing/stack_map_test.cc
index 9db7588b3a..c372bb9b22 100644
--- a/compiler/optimizing/stack_map_test.cc
+++ b/compiler/optimizing/stack_map_test.cc
@@ -32,10 +32,10 @@ static bool CheckStackMask(
     const StackMap& stack_map,
     const BitVector& bit_vector) {
   BitMemoryRegion stack_mask = code_info.GetStackMaskOf(stack_map);
-  if (bit_vector.GetNumberOfBits() > code_info.GetNumberOfStackMaskBits()) {
+  if (bit_vector.GetNumberOfBits() > stack_mask.size_in_bits()) {
     return false;
   }
-  for (size_t i = 0; i < code_info.GetNumberOfStackMaskBits(); ++i) {
+  for (size_t i = 0; i < stack_mask.size_in_bits(); ++i) {
     if (stack_mask.LoadBit(i) != bit_vector.IsBitSet(i)) {
       return false;
     }