Add hash map, reduce excessive hashing
Changed the class def index to use a HashMap instead of unordered_map
so that we can use FindWithHash to reduce how often we need to compute
hashes.
Fixed a bug in ClassLinker::UpdateClass where we didn't properly
handle classes with the same descriptor but different class loaders.
Introduced by previous CL.
Before (fb launch):
1.74% art::ComputeModifiedUtf8Hash(char const*)
After:
0.95% art::ComputeModifiedUtf8Hash(char const*)
Bug: 18054905
Bug: 16828525
Change-Id: Iba2ee37c9837289e0ea187800ba4af322225a994
(cherry picked from commit 564ff985184737977aa26c485d0c1a413e530705)
diff --git a/runtime/native/dalvik_system_DexFile.cc b/runtime/native/dalvik_system_DexFile.cc
index 012e03e..f37312e 100644
--- a/runtime/native/dalvik_system_DexFile.cc
+++ b/runtime/native/dalvik_system_DexFile.cc
@@ -185,9 +185,9 @@
return NULL;
}
const std::string descriptor(DotToDescriptor(class_name.c_str()));
-
+ const size_t hash(ComputeModifiedUtf8Hash(descriptor.c_str()));
for (const DexFile* dex_file : *dex_files) {
- const DexFile::ClassDef* dex_class_def = dex_file->FindClassDef(descriptor.c_str());
+ const DexFile::ClassDef* dex_class_def = dex_file->FindClassDef(descriptor.c_str(), hash);
if (dex_class_def != nullptr) {
ScopedObjectAccess soa(env);
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
@@ -195,7 +195,7 @@
StackHandleScope<1> hs(soa.Self());
Handle<mirror::ClassLoader> class_loader(
hs.NewHandle(soa.Decode<mirror::ClassLoader*>(javaLoader)));
- mirror::Class* result = class_linker->DefineClass(soa.Self(), descriptor.c_str(),
+ mirror::Class* result = class_linker->DefineClass(soa.Self(), descriptor.c_str(), hash,
class_loader, *dex_file, *dex_class_def);
if (result != nullptr) {
VLOG(class_linker) << "DexFile_defineClassNative returning " << result