commit e03662b71bbb4d262af0840bf90ce4fc84750b43
author Andreas Gampe <agampe@google.com> Thu Oct 13 17:12:56 2016 -0700
committer Andreas Gampe <agampe@google.com> Mon Oct 24 19:16:54 2016 -0700
tree 0d89f7d90a46a7a2f8d120e3b0aabf3e1d277004
parent dc061d038e4e48fe2a967fd4a9c200d112df5698

ART: Change IndirectReferenceTable

Change cookie structure to allow for more entries. Use a local
hole-count caching scheme. The design is driven by two
considerations. For one, the change is small and mostly local.
The other point is to still allow inlining of functions involved
with JNI transitions.

This change is in preparation for a resizable backing table for
"unlimite" local references.

micro_native tests show changes are in the noise.

Bug: 32125344
Test: m test-art-host
Change-Id: I08ff5d6eaed75d13ec88f469fb0d18328a0eeb70

runtime/entrypoints/quick/quick_jni_entrypoints.cc

diff --git a/runtime/entrypoints/quick/quick_jni_entrypoints.cc b/runtime/entrypoints/quick/quick_jni_entrypoints.cc
index 330c742..670dadc 100644
--- a/runtime/entrypoints/quick/quick_jni_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_jni_entrypoints.cc
@@ -15,13 +15,18 @@
  */
 
 #include "art_method-inl.h"
+#include "base/casts.h"
 #include "entrypoints/entrypoint_utils-inl.h"
+#include "indirect_reference_table.h"
 #include "mirror/object-inl.h"
 #include "thread-inl.h"
 #include "verify_object-inl.h"
 
 namespace art {
 
+static_assert(sizeof(IRTSegmentState) == sizeof(uint32_t), "IRTSegmentState size unexpected");
+static_assert(std::is_trivial<IRTSegmentState>::value, "IRTSegmentState not trivial");
+
 template <bool kDynamicFast>
 static inline void GoToRunnableFast(Thread* self) NO_THREAD_SAFETY_ANALYSIS;
 
@@ -45,7 +50,7 @@
 extern uint32_t JniMethodFastStart(Thread* self) {
   JNIEnvExt* env = self->GetJniEnv();
   DCHECK(env != nullptr);
-  uint32_t saved_local_ref_cookie = env->local_ref_cookie;
+  uint32_t saved_local_ref_cookie = bit_cast<uint32_t>(env->local_ref_cookie);
   env->local_ref_cookie = env->locals.GetSegmentState();
 
   if (kIsDebugBuild) {
@@ -60,7 +65,7 @@
 extern uint32_t JniMethodStart(Thread* self) {
   JNIEnvExt* env = self->GetJniEnv();
   DCHECK(env != nullptr);
-  uint32_t saved_local_ref_cookie = env->local_ref_cookie;
+  uint32_t saved_local_ref_cookie = bit_cast<uint32_t>(env->local_ref_cookie);
   env->local_ref_cookie = env->locals.GetSegmentState();
   ArtMethod* native_method = *self->GetManagedStack()->GetTopQuickFrame();
   if (!native_method->IsFastNative()) {
@@ -117,7 +122,7 @@
     env->CheckNoHeldMonitors();
   }
   env->locals.SetSegmentState(env->local_ref_cookie);
-  env->local_ref_cookie = saved_local_ref_cookie;
+  env->local_ref_cookie = bit_cast<IRTSegmentState>(saved_local_ref_cookie);
   self->PopHandleScope();
 }