Avoid read barriers for ArtMethod::GetDexFile

Shows up in pmd benchmark from Class::FindDeclaredDirectMethod and
Class::FindDeclaredVirtualMethod. There are still calls to
IsProxyMethod that could probably be eliminated.

ReadBarrier::Mark goes from 12.39% to 3.45% according to perf.

Test: test-art-host

Change-Id: I6a4f2fa2d68bf5f393f83b9b70e8d6fcc9dbdaa2

diff --git a/runtime/art_method-inl.h b/runtime/art_method-inl.h
index a35c7ab..7ec3900 100644 (file)
--- a/runtime/art_method-inl.h
+++ b/runtime/art_method-inl.h
@@ -244,7 +244,9 @@ inline bool ArtMethod::IsImtUnimplementedMethod() {
 }
 
 inline const DexFile* ArtMethod::GetDexFile() {
-  return GetDexCache()->GetDexFile();
+  // It is safe to avoid the read barrier here since the dex file is constant, so if we read the
+  // from-space dex file pointer it will be equal to the to-space copy.
+  return GetDexCache<kWithoutReadBarrier>()->GetDexFile();
 }
 
 inline const char* ArtMethod::GetDeclaringClassDescriptor() {
@@ -361,9 +363,11 @@ inline mirror::ClassLoader* ArtMethod::GetClassLoader() {
   return GetDeclaringClass()->GetClassLoader();
 }
 
+template <ReadBarrierOption kReadBarrierOption>
 inline mirror::DexCache* ArtMethod::GetDexCache() {
   if (LIKELY(!IsObsolete())) {
-    return GetDeclaringClass()->GetDexCache();
+    mirror::Class* klass = GetDeclaringClass<kReadBarrierOption>();
+    return klass->GetDexCache<kDefaultVerifyFlags, kReadBarrierOption>();
   } else {
     DCHECK(!IsProxyMethod());
     return GetObsoleteDexCache();
@@ -379,14 +383,13 @@ inline ArtMethod* ArtMethod::GetInterfaceMethodIfProxy(PointerSize pointer_size)
   if (LIKELY(!IsProxyMethod())) {
     return this;
   }
-  mirror::Class* klass = GetDeclaringClass();
   ArtMethod* interface_method = mirror::DexCache::GetElementPtrSize(
       GetDexCacheResolvedMethods(pointer_size),
       GetDexMethodIndex(),
       pointer_size);
   DCHECK(interface_method != nullptr);
   DCHECK_EQ(interface_method,
-            Runtime::Current()->GetClassLinker()->FindMethodForProxy(klass, this));
+            Runtime::Current()->GetClassLinker()->FindMethodForProxy(GetDeclaringClass(), this));
   return interface_method;
 }
 

diff --git a/runtime/art_method.h b/runtime/art_method.h
index 17f343d..7217ead 100644 (file)
--- a/runtime/art_method.h
+++ b/runtime/art_method.h
@@ -563,6 +563,7 @@ class ArtMethod FINAL {
 
   mirror::ClassLoader* GetClassLoader() REQUIRES_SHARED(Locks::mutator_lock_);
 
+  template <ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
   mirror::DexCache* GetDexCache() REQUIRES_SHARED(Locks::mutator_lock_);
   mirror::DexCache* GetObsoleteDexCache() REQUIRES_SHARED(Locks::mutator_lock_);
 

diff --git a/runtime/mirror/class-inl.h b/runtime/mirror/class-inl.h
index 2fb8d28..6a65e12 100644 (file)
--- a/runtime/mirror/class-inl.h
+++ b/runtime/mirror/class-inl.h
@@ -71,9 +71,10 @@ inline ClassLoader* Class::GetClassLoader() {
       OFFSET_OF_OBJECT_MEMBER(Class, class_loader_));
 }
 
-template<VerifyObjectFlags kVerifyFlags>
+template<VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
 inline DexCache* Class::GetDexCache() {
-  return GetFieldObject<DexCache, kVerifyFlags>(OFFSET_OF_OBJECT_MEMBER(Class, dex_cache_));
+  return GetFieldObject<DexCache, kVerifyFlags, kReadBarrierOption>(
+      OFFSET_OF_OBJECT_MEMBER(Class, dex_cache_));
 }
 
 inline uint32_t Class::GetCopiedMethodsStartOffset() {

diff --git a/runtime/mirror/class.h b/runtime/mirror/class.h
index 7f6aa12..c9f27ad 100644 (file)
--- a/runtime/mirror/class.h
+++ b/runtime/mirror/class.h
@@ -722,7 +722,8 @@ class MANAGED Class FINAL : public Object {
 
   void DumpClass(std::ostream& os, int flags) REQUIRES_SHARED(Locks::mutator_lock_);
 
-  template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
+  template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
+           ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
   DexCache* GetDexCache() REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Also updates the dex_cache_strings_ variable from new_dex_cache.