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/class_linker_test.cc

diff --git a/runtime/class_linker_test.cc b/runtime/class_linker_test.cc
index 488826b..9b59f2b 100644
--- a/runtime/class_linker_test.cc
+++ b/runtime/class_linker_test.cc
@@ -148,7 +148,8 @@
     EXPECT_EQ(0U, array->NumInstanceFields());
     EXPECT_EQ(0U, array->NumStaticFields());
     EXPECT_EQ(2U, array->NumDirectInterfaces());
-    EXPECT_TRUE(array->ShouldHaveEmbeddedImtAndVTable());
+    EXPECT_FALSE(array->ShouldHaveImt());
+    EXPECT_TRUE(array->ShouldHaveEmbeddedVTable());
     EXPECT_EQ(2, array->GetIfTableCount());
     ASSERT_TRUE(array->GetIfTable() != nullptr);
     mirror::Class* direct_interface0 = mirror::Class::GetDirectInterface(self, array, 0);