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8246546: Simplify SystemDictionary::is_shared_class_visible

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Reviewed-by: minqi, ccheung
This commit is contained in:
Ioi Lam 2020-06-23 21:23:00 -07:00
parent e178f0467b
commit 27fc8b6787
8 changed files with 127 additions and 186 deletions
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110
src/hotspot/share/classfile/systemDictionaryShared.cpp
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@ -886,114 +886,6 @@ bool SystemDictionaryShared::is_sharing_possible(ClassLoaderData* loader_data) {
SystemDictionary::is_platform_class_loader(class_loader));
}
// Currently AppCDS only archives classes from the run-time image, the
// -Xbootclasspath/a path, the class path, and the module path.
//
// Check if a shared class can be loaded by the specific classloader. Following
// are the "visible" archived classes for different classloaders.
//
// NULL classloader:
// - see SystemDictionary::is_shared_class_visible()
// Platform classloader:
// - Module class from runtime image. ModuleEntry must be defined in the
// classloader.
// App classloader:
// - Module Class from runtime image and module path. ModuleEntry must be defined in the
// classloader.
// - Class from -cp. The class must have no PackageEntry defined in any of the
// boot/platform/app classloader, or must be in the unnamed module defined in the
// AppClassLoader.
bool SystemDictionaryShared::is_shared_class_visible_for_classloader(
InstanceKlass* ik,
Handle class_loader,
Symbol* pkg_name,
PackageEntry* pkg_entry,
ModuleEntry* mod_entry,
TRAPS) {
assert(class_loader.not_null(), "Class loader should not be NULL");
assert(Universe::is_module_initialized(), "Module system is not initialized");
ResourceMark rm(THREAD);
int path_index = ik->shared_classpath_index();
SharedClassPathEntry* ent =
(SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
if (SystemDictionary::is_platform_class_loader(class_loader())) {
assert(ent != NULL, "shared class for PlatformClassLoader should have valid SharedClassPathEntry");
// The PlatformClassLoader can only load archived class originated from the
// run-time image. The class' PackageEntry/ModuleEntry must be
// defined by the PlatformClassLoader.
if (mod_entry != NULL) {
// PackageEntry/ModuleEntry is found in the classloader. Check if the
// ModuleEntry's location agrees with the archived class' origination.
if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
return true; // Module class from the runtime image
}
}
} else if (SystemDictionary::is_system_class_loader(class_loader())) {
assert(ent != NULL, "shared class for system loader should have valid SharedClassPathEntry");
if (pkg_name == NULL) {
// The archived class is in the unnamed package. Currently, the boot image
// does not contain any class in the unnamed package.
assert(!ent->is_modules_image(), "Class in the unnamed package must be from the classpath");
if (path_index >= ClassLoaderExt::app_class_paths_start_index()) {
assert(path_index < ClassLoaderExt::app_module_paths_start_index(), "invalid path_index");
return true;
}
} else {
// Check if this is from a PackageEntry/ModuleEntry defined in the AppClassloader.
if (pkg_entry == NULL) {
// It's not guaranteed that the class is from the classpath if the
// PackageEntry cannot be found from the AppClassloader. Need to check
// the boot and platform classloader as well.
ClassLoaderData* platform_loader_data =
ClassLoaderData::class_loader_data_or_null(SystemDictionary::java_platform_loader()); // can be NULL during bootstrap
if ((platform_loader_data == NULL ||
ClassLoader::get_package_entry(pkg_name, platform_loader_data) == NULL) &&
ClassLoader::get_package_entry(pkg_name, ClassLoaderData::the_null_class_loader_data()) == NULL) {
// The PackageEntry is not defined in any of the boot/platform/app classloaders.
// The archived class must from -cp path and not from the runtime image.
if (!ent->is_modules_image() && path_index >= ClassLoaderExt::app_class_paths_start_index() &&
path_index < ClassLoaderExt::app_module_paths_start_index()) {
return true;
}
}
} else if (mod_entry != NULL) {
// The package/module is defined in the AppClassLoader. We support
// archiving application module class from the runtime image or from
// a named module from a module path.
// Packages from the -cp path are in the unnamed_module.
if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
// shared module class from runtime image
return true;
} else if (pkg_entry->in_unnamed_module() && path_index >= ClassLoaderExt::app_class_paths_start_index() &&
path_index < ClassLoaderExt::app_module_paths_start_index()) {
// shared class from -cp
DEBUG_ONLY( \
ClassLoaderData* loader_data = class_loader_data(class_loader); \
assert(mod_entry == loader_data->unnamed_module(), "the unnamed module is not defined in the classloader");)
return true;
} else {
if(!pkg_entry->in_unnamed_module() &&
(path_index >= ClassLoaderExt::app_module_paths_start_index())&&
(path_index < FileMapInfo::get_number_of_shared_paths()) &&
(strcmp(ent->name(), ClassLoader::skip_uri_protocol(mod_entry->location()->as_C_string())) == 0)) {
// shared module class from module path
return true;
} else {
assert(path_index < FileMapInfo::get_number_of_shared_paths(), "invalid path_index");
}
}
}
}
} else {
// TEMP: if a shared class can be found by a custom loader, consider it visible now.
// FIXME: is this actually correct?
return true;
}
return false;
}
bool SystemDictionaryShared::has_platform_or_app_classes() {
if (FileMapInfo::current_info()->has_platform_or_app_classes()) {
return true;
@ -1026,7 +918,7 @@ bool SystemDictionaryShared::has_platform_or_app_classes() {
// [b] BuiltinClassLoader.loadClassOrNull() first calls findLoadedClass(name).
// [c] At this point, if we can find the named class inside the
// shared_dictionary, we can perform further checks (see
// is_shared_class_visible_for_classloader() to ensure that this class
// SystemDictionary::is_shared_class_visible) to ensure that this class
// was loaded by the same class loader during dump time.
//
// Given these assumptions, we intercept the findLoadedClass() call to invoke