Compiler changes for bitstring based type checks.

We guard the use of this feature with a compile-time flag,
set to true in this CL.

Boot image size for aosp_taimen-userdebug in AOSP master:
  - before:
    arm boot*.oat: 63604740
    arm64 boot*.oat: 74237864
  - after:
    arm boot*.oat: 63531172 (-72KiB, -0.1%)
    arm64 boot*.oat: 74135008 (-100KiB, -0.1%)

The new TypeCheckBenchmark yields the following changes
using the little cores of taimen fixed at 1.4016GHz:
                               32-bit        64-bit
  timeCheckCastLevel1ToLevel1  11.48->15.80 11.47->15.78
  timeCheckCastLevel2ToLevel1  15.08->15.79 15.08->15.79
  timeCheckCastLevel3ToLevel1  19.01->15.82 17.94->15.81
  timeCheckCastLevel9ToLevel1  42.55->15.79 42.63->15.81
  timeCheckCastLevel9ToLevel2  39.70->14.36 39.70->14.35
  timeInstanceOfLevel1ToLevel1 13.74->17.93 13.76->17.95
  timeInstanceOfLevel2ToLevel1 17.02->17.95 16.99->17.93
  timeInstanceOfLevel3ToLevel1 24.03->17.95 24.45->17.95
  timeInstanceOfLevel9ToLevel1 47.13->17.95 47.14->18.00
  timeInstanceOfLevel9ToLevel2 44.19->16.52 44.27->16.51
This suggests that the bitstring typecheck should not be
used for exact type checks which would be equivalent to the
"Level1ToLevel1" benchmark. Whether the implementation is
a beneficial replacement for the kClassHierarchyCheck and
kAbstractClassCheck on average depends on how many levels
from the target class (or Object for a negative result) is
a typical object's class.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --jit
Test: testrunner.py --host -t 670-bitstring-type-check
Test: Pixel 2 XL boots.
Test: testrunner.py --target --optimizing --jit
Test: testrunner.py --target -t 670-bitstring-type-check
Bug: 64692057
Bug: 71853552
Bug: 26687569
Change-Id: I538d7e036b5a8ae2cc3fe77662a5903d74854562

1 files changed, 1 insertions, 0 deletions

diff --git a/compiler/optimizing/optimizing_compiler_stats.h b/compiler/optimizing/optimizing_compiler_stats.h
index 0023265e50..a6a2f46d2e 100644
--- a/compiler/optimizing/optimizing_compiler_stats.h
+++ b/compiler/optimizing/optimizing_compiler_stats.h
@@ -99,6 +99,7 @@ enum class MethodCompilationStat {
   kConstructorFenceRemovedLSE,
   kConstructorFenceRemovedPFRA,
   kConstructorFenceRemovedCFRE,
+  kBitstringTypeCheck,
   kJitOutOfMemoryForCommit,
   kLastStat
 };