From ab0ed82ff64ba5a751dcc0a38d0e0c41c53dc923 Mon Sep 17 00:00:00 2001 From: Mathieu Chartier Date: Thu, 11 Sep 2014 14:21:41 -0700 Subject: Add fast path to VMClassLoader.findLoadedClass VMClassLoader.findLoadedClass now calls FindClassInPathClassLoader as a fast path. Exclusive time results (trace view maps launch): Before: nativeFillInStackTrace 1.4% defineClassNative 1.2% findLoadedClass 0.2% After: nativeFillInStackTrace 0.5% defineClassNative 0.0% findLoadedClass 0.9% (cherry picked from commit 194116c836080de14245a3a7c4617d07b8abf8cf) Change-Id: I63fd7b4bccb71789e92bd39d1d3f9d0de22535de --- runtime/class_linker.cc | 169 +++++++++++++++++++++++++----------------------- 1 file changed, 88 insertions(+), 81 deletions(-) (limited to 'runtime/class_linker.cc') diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc index f94535c718..16cddd5f71 100644 --- a/runtime/class_linker.cc +++ b/runtime/class_linker.cc @@ -2071,6 +2071,91 @@ ClassPathEntry FindInClassPath(const char* descriptor, reinterpret_cast(NULL)); } +mirror::Class* ClassLinker::FindClassInPathClassLoader(ScopedObjectAccessAlreadyRunnable& soa, + Thread* self, const char* descriptor, + ConstHandle class_loader) { + if (class_loader->GetClass() != + soa.Decode(WellKnownClasses::dalvik_system_PathClassLoader) || + class_loader->GetParent()->GetClass() != + soa.Decode(WellKnownClasses::java_lang_BootClassLoader)) { + return nullptr; + } + ClassPathEntry pair = FindInClassPath(descriptor, boot_class_path_); + // Check if this would be found in the parent boot class loader. + if (pair.second != nullptr) { + mirror::Class* klass = LookupClass(descriptor, nullptr); + if (klass != nullptr) { + return EnsureResolved(self, descriptor, klass); + } + klass = DefineClass(descriptor, NullHandle(), *pair.first, + *pair.second); + if (klass != nullptr) { + return klass; + } + CHECK(self->IsExceptionPending()) << descriptor; + self->ClearException(); + } else { + // RegisterDexFile may allocate dex caches (and cause thread suspension). + StackHandleScope<3> hs(self); + // The class loader is a PathClassLoader which inherits from BaseDexClassLoader. + // We need to get the DexPathList and loop through it. + Handle cookie_field = + hs.NewHandle(soa.DecodeField(WellKnownClasses::dalvik_system_DexFile_cookie)); + Handle dex_file_field = + hs.NewHandle( + soa.DecodeField(WellKnownClasses::dalvik_system_DexPathList$Element_dexFile)); + mirror::Object* dex_path_list = + soa.DecodeField(WellKnownClasses::dalvik_system_PathClassLoader_pathList)-> + GetObject(class_loader.Get()); + if (dex_path_list != nullptr && dex_file_field.Get() != nullptr && + cookie_field.Get() != nullptr) { + // DexPathList has an array dexElements of Elements[] which each contain a dex file. + mirror::Object* dex_elements_obj = + soa.DecodeField(WellKnownClasses::dalvik_system_DexPathList_dexElements)-> + GetObject(dex_path_list); + // Loop through each dalvik.system.DexPathList$Element's dalvik.system.DexFile and look + // at the mCookie which is a DexFile vector. + if (dex_elements_obj != nullptr) { + Handle> dex_elements = + hs.NewHandle(dex_elements_obj->AsObjectArray()); + for (int32_t i = 0; i < dex_elements->GetLength(); ++i) { + mirror::Object* element = dex_elements->GetWithoutChecks(i); + if (element == nullptr) { + // Should never happen, fall back to java code to throw a NPE. + break; + } + mirror::Object* dex_file = dex_file_field->GetObject(element); + if (dex_file != nullptr) { + const uint64_t cookie = cookie_field->GetLong(dex_file); + auto* dex_files = + reinterpret_cast*>(static_cast(cookie)); + if (dex_files == nullptr) { + // This should never happen so log a warning. + LOG(WARNING) << "Null DexFile::mCookie for " << descriptor; + break; + } + for (const DexFile* dex_file : *dex_files) { + const DexFile::ClassDef* dex_class_def = dex_file->FindClassDef(descriptor); + if (dex_class_def != nullptr) { + RegisterDexFile(*dex_file); + mirror::Class* klass = + DefineClass(descriptor, class_loader, *dex_file, *dex_class_def); + if (klass == nullptr) { + CHECK(self->IsExceptionPending()) << descriptor; + self->ClearException(); + return nullptr; + } + return klass; + } + } + } + } + } + } + } + return nullptr; +} + mirror::Class* ClassLinker::FindClass(Thread* self, const char* descriptor, ConstHandle class_loader) { DCHECK_NE(*descriptor, '\0') << "descriptor is empty string"; @@ -2114,7 +2199,6 @@ mirror::Class* ClassLinker::FindClass(Thread* self, const char* descriptor, // a NoClassDefFoundError being allocated. ClassPathEntry pair = FindInClassPath(descriptor, boot_class_path_); if (pair.second != nullptr) { - StackHandleScope<1> hs(self); return DefineClass(descriptor, NullHandle(), *pair.first, *pair.second); } // Next try the compile time class path. @@ -2131,86 +2215,9 @@ mirror::Class* ClassLinker::FindClass(Thread* self, const char* descriptor, } } else { ScopedObjectAccessUnchecked soa(self); - if (class_loader->GetClass() == - soa.Decode(WellKnownClasses::dalvik_system_PathClassLoader) && - class_loader->GetParent()->GetClass() == - soa.Decode(WellKnownClasses::java_lang_BootClassLoader)) { - ClassPathEntry pair = FindInClassPath(descriptor, boot_class_path_); - // Check if this would be found in the parent boot class loader. - if (pair.second != nullptr) { - mirror::Class* klass = LookupClass(descriptor, nullptr); - if (klass != nullptr) { - return EnsureResolved(self, descriptor, klass); - } - klass = DefineClass(descriptor, NullHandle(), *pair.first, - *pair.second); - if (klass == nullptr) { - CHECK(self->IsExceptionPending()) << descriptor; - self->ClearException(); - } else { - return klass; - } - } else { - // RegisterDexFile may allocate dex caches (and cause thread suspension). - StackHandleScope<3> hs(self); - // The class loader is a PathClassLoader which inherits from BaseDexClassLoader. - // We need to get the DexPathList and loop through it. - Handle cookie_field = - hs.NewHandle(soa.DecodeField(WellKnownClasses::dalvik_system_DexFile_cookie)); - Handle dex_file_field = - hs.NewHandle( - soa.DecodeField(WellKnownClasses::dalvik_system_DexPathList$Element_dexFile)); - mirror::Object* dex_path_list = - soa.DecodeField(WellKnownClasses::dalvik_system_PathClassLoader_pathList)-> - GetObject(class_loader.Get()); - if (dex_path_list != nullptr && dex_file_field.Get() != nullptr && - cookie_field.Get() != nullptr) { - // DexPathList has an array dexElements of Elements[] which each contain a dex file. - mirror::Object* dex_elements_obj = - soa.DecodeField(WellKnownClasses::dalvik_system_DexPathList_dexElements)-> - GetObject(dex_path_list); - // Loop through each dalvik.system.DexPathList$Element's dalvik.system.DexFile and look - // at the mCookie which is a DexFile vector. - if (dex_elements_obj != nullptr) { - Handle> dex_elements = - hs.NewHandle(dex_elements_obj->AsObjectArray()); - for (int32_t i = 0; i < dex_elements->GetLength(); ++i) { - mirror::Object* element = dex_elements->GetWithoutChecks(i); - if (element == nullptr) { - // Should never happen, fall back to java code to throw a NPE. - break; - } - mirror::Object* dex_file = dex_file_field->GetObject(element); - if (dex_file != nullptr) { - const uint64_t cookie = cookie_field->GetLong(dex_file); - auto* dex_files = - reinterpret_cast*>(static_cast(cookie)); - if (dex_files == nullptr) { - // This should never happen so log a warning. - LOG(WARNING) << "Null DexFile::mCookie for " << descriptor; - break; - } - for (const DexFile* dex_file : *dex_files) { - const DexFile::ClassDef* dex_class_def = dex_file->FindClassDef(descriptor); - if (dex_class_def != nullptr) { - RegisterDexFile(*dex_file); - mirror::Class* klass = - DefineClass(descriptor, class_loader, *dex_file, *dex_class_def); - if (klass == nullptr) { - CHECK(self->IsExceptionPending()) << descriptor; - self->ClearException(); - // Exit the loop to make the java code generate an exception. - i = dex_elements->GetLength(); - break; - } - return klass; - } - } - } - } - } - } - } + mirror::Class* klass = FindClassInPathClassLoader(soa, self, descriptor, class_loader); + if (klass != nullptr) { + return klass; } ScopedLocalRef class_loader_object(soa.Env(), soa.AddLocalReference(class_loader.Get())); -- cgit v1.2.3-59-g8ed1b