commit badee9820fcf5dca5f8c46c3215ae1779ee7736e
author Nelli Kim <nelli.kim@samsung.com> Fri May 13 13:08:53 2016 +0300
committer Matthew Gharrity <gharrma@google.com> Tue Jun 14 10:05:47 2016 -0700
tree 982948a67a88a1f9a734c935f919f8d307969f48
parent 614968198625a6693666bdc1e5609e2f663f5638

Optimize IMT

* Remove IMT for classes which do not implement interfaces
* Remove IMT for array classes
* Share same IMT

Saved memory (measured on hammerhead):
boot.art:
Total number of classes: 3854
Number of affected classes: 1637
Saved memory: 409kB

Chrome (excluding classes in boot.art):
Total number of classes: 2409
Number of affected classes: 1259
Saved memory: 314kB

Google Maps (excluding classes in boot.art):
Total number of classes: 6988
Number of affected classes: 2574
Saved memory: 643kB

Performance regression on benchmarks/InvokeInterface.java benchmark
(measured timeCall10Interface)
1st launch: 9.6%
2nd launch: 6.8%

Change-Id: If07e45390014a6ee8f3c1c4ca095b43046f0871f

runtime/interpreter/interpreter_common.h

diff --git a/runtime/interpreter/interpreter_common.h b/runtime/interpreter/interpreter_common.h
index cc470f3..3750b7a 100644
--- a/runtime/interpreter/interpreter_common.h
+++ b/runtime/interpreter/interpreter_common.h
@@ -679,7 +679,7 @@
     return false;
   }
   const uint32_t vtable_idx = (is_range) ? inst->VRegB_3rc() : inst->VRegB_35c();
-  CHECK(receiver->GetClass()->ShouldHaveEmbeddedImtAndVTable());
+  CHECK(receiver->GetClass()->ShouldHaveEmbeddedVTable());
   ArtMethod* const called_method = receiver->GetClass()->GetEmbeddedVTableEntry(
       vtable_idx, sizeof(void*));
   if (UNLIKELY(called_method == nullptr)) {