| /* |
| * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "classfile/systemDictionary.hpp" |
| #include "classfile/vmSymbols.hpp" |
| #include "gc_implementation/shared/markSweep.inline.hpp" |
| #include "memory/gcLocker.hpp" |
| #include "memory/metaspaceShared.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "memory/universe.inline.hpp" |
| #include "oops/instanceKlass.hpp" |
| #include "oops/klassVtable.hpp" |
| #include "oops/method.hpp" |
| #include "oops/objArrayOop.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "prims/jvmtiRedefineClassesTrace.hpp" |
| #include "runtime/arguments.hpp" |
| #include "runtime/handles.inline.hpp" |
| #include "utilities/copy.hpp" |
| |
| PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
| |
| inline InstanceKlass* klassVtable::ik() const { |
| Klass* k = _klass(); |
| assert(k->oop_is_instance(), "not an InstanceKlass"); |
| return (InstanceKlass*)k; |
| } |
| |
| bool klassVtable::is_preinitialized_vtable() { |
| return _klass->is_shared() && !MetaspaceShared::remapped_readwrite(); |
| } |
| |
| |
| // this function computes the vtable size (including the size needed for miranda |
| // methods) and the number of miranda methods in this class. |
| // Note on Miranda methods: Let's say there is a class C that implements |
| // interface I, and none of C's superclasses implements I. |
| // Let's say there is an abstract method m in I that neither C |
| // nor any of its super classes implement (i.e there is no method of any access, |
| // with the same name and signature as m), then m is a Miranda method which is |
| // entered as a public abstract method in C's vtable. From then on it should |
| // treated as any other public method in C for method over-ride purposes. |
| void klassVtable::compute_vtable_size_and_num_mirandas( |
| int* vtable_length_ret, int* num_new_mirandas, |
| GrowableArray<Method*>* all_mirandas, Klass* super, |
| Array<Method*>* methods, AccessFlags class_flags, |
| Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces, |
| TRAPS) { |
| No_Safepoint_Verifier nsv; |
| |
| // set up default result values |
| int vtable_length = 0; |
| |
| // start off with super's vtable length |
| InstanceKlass* sk = (InstanceKlass*)super; |
| vtable_length = super == NULL ? 0 : sk->vtable_length(); |
| |
| // go thru each method in the methods table to see if it needs a new entry |
| int len = methods->length(); |
| for (int i = 0; i < len; i++) { |
| assert(methods->at(i)->is_method(), "must be a Method*"); |
| methodHandle mh(THREAD, methods->at(i)); |
| |
| if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) { |
| vtable_length += vtableEntry::size(); // we need a new entry |
| } |
| } |
| |
| GrowableArray<Method*> new_mirandas(20); |
| // compute the number of mirandas methods that must be added to the end |
| get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces); |
| *num_new_mirandas = new_mirandas.length(); |
| |
| // Interfaces do not need interface methods in their vtables |
| // This includes miranda methods and during later processing, default methods |
| if (!class_flags.is_interface()) { |
| vtable_length += *num_new_mirandas * vtableEntry::size(); |
| } |
| |
| if (Universe::is_bootstrapping() && vtable_length == 0) { |
| // array classes don't have their superclass set correctly during |
| // bootstrapping |
| vtable_length = Universe::base_vtable_size(); |
| } |
| |
| if (super == NULL && !Universe::is_bootstrapping() && |
| vtable_length != Universe::base_vtable_size()) { |
| // Someone is attempting to redefine java.lang.Object incorrectly. The |
| // only way this should happen is from |
| // SystemDictionary::resolve_from_stream(), which will detect this later |
| // and throw a security exception. So don't assert here to let |
| // the exception occur. |
| vtable_length = Universe::base_vtable_size(); |
| } |
| assert(super != NULL || vtable_length == Universe::base_vtable_size(), |
| "bad vtable size for class Object"); |
| assert(vtable_length % vtableEntry::size() == 0, "bad vtable length"); |
| assert(vtable_length >= Universe::base_vtable_size(), "vtable too small"); |
| |
| *vtable_length_ret = vtable_length; |
| } |
| |
| int klassVtable::index_of(Method* m, int len) const { |
| assert(m->has_vtable_index(), "do not ask this of non-vtable methods"); |
| return m->vtable_index(); |
| } |
| |
| // Copy super class's vtable to the first part (prefix) of this class's vtable, |
| // and return the number of entries copied. Expects that 'super' is the Java |
| // super class (arrays can have "array" super classes that must be skipped). |
| int klassVtable::initialize_from_super(KlassHandle super) { |
| if (super.is_null()) { |
| return 0; |
| } else if (is_preinitialized_vtable()) { |
| // A shared class' vtable is preinitialized at dump time. No need to copy |
| // methods from super class for shared class, as that was already done |
| // during archiving time. However, if Jvmti has redefined a class, |
| // copy super class's vtable in case the super class has changed. |
| return super->vtable()->length(); |
| } else { |
| // copy methods from superKlass |
| // can't inherit from array class, so must be InstanceKlass |
| assert(super->oop_is_instance(), "must be instance klass"); |
| InstanceKlass* sk = (InstanceKlass*)super(); |
| klassVtable* superVtable = sk->vtable(); |
| assert(superVtable->length() <= _length, "vtable too short"); |
| #ifdef ASSERT |
| superVtable->verify(tty, true); |
| #endif |
| superVtable->copy_vtable_to(table()); |
| #ifndef PRODUCT |
| if (PrintVtables && Verbose) { |
| ResourceMark rm; |
| tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length); |
| } |
| #endif |
| return superVtable->length(); |
| } |
| } |
| |
| // |
| // Revised lookup semantics introduced 1.3 (Kestrel beta) |
| void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) { |
| |
| // Note: Arrays can have intermediate array supers. Use java_super to skip them. |
| KlassHandle super (THREAD, klass()->java_super()); |
| int nofNewEntries = 0; |
| |
| bool is_shared = _klass->is_shared(); |
| |
| if (PrintVtables && !klass()->oop_is_array()) { |
| ResourceMark rm(THREAD); |
| tty->print_cr("Initializing: %s", _klass->name()->as_C_string()); |
| } |
| |
| #ifdef ASSERT |
| oop* end_of_obj = (oop*)_klass() + _klass()->size(); |
| oop* end_of_vtable = (oop*)&table()[_length]; |
| assert(end_of_vtable <= end_of_obj, "vtable extends beyond end"); |
| #endif |
| |
| if (Universe::is_bootstrapping()) { |
| assert(!is_shared, "sanity"); |
| // just clear everything |
| for (int i = 0; i < _length; i++) table()[i].clear(); |
| return; |
| } |
| |
| int super_vtable_len = initialize_from_super(super); |
| if (klass()->oop_is_array()) { |
| assert(super_vtable_len == _length, "arrays shouldn't introduce new methods"); |
| } else { |
| assert(_klass->oop_is_instance(), "must be InstanceKlass"); |
| |
| Array<Method*>* methods = ik()->methods(); |
| int len = methods->length(); |
| int initialized = super_vtable_len; |
| |
| // Check each of this class's methods against super; |
| // if override, replace in copy of super vtable, otherwise append to end |
| for (int i = 0; i < len; i++) { |
| // update_inherited_vtable can stop for gc - ensure using handles |
| HandleMark hm(THREAD); |
| assert(methods->at(i)->is_method(), "must be a Method*"); |
| methodHandle mh(THREAD, methods->at(i)); |
| |
| bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK); |
| |
| if (needs_new_entry) { |
| put_method_at(mh(), initialized); |
| mh()->set_vtable_index(initialized); // set primary vtable index |
| initialized++; |
| } |
| } |
| |
| // update vtable with default_methods |
| Array<Method*>* default_methods = ik()->default_methods(); |
| if (default_methods != NULL) { |
| len = default_methods->length(); |
| if (len > 0) { |
| Array<int>* def_vtable_indices = NULL; |
| if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) { |
| assert(!is_shared, "shared class def_vtable_indices does not exist"); |
| def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK); |
| } else { |
| assert(def_vtable_indices->length() == len, "reinit vtable len?"); |
| } |
| for (int i = 0; i < len; i++) { |
| HandleMark hm(THREAD); |
| assert(default_methods->at(i)->is_method(), "must be a Method*"); |
| methodHandle mh(THREAD, default_methods->at(i)); |
| |
| bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK); |
| |
| // needs new entry |
| if (needs_new_entry) { |
| put_method_at(mh(), initialized); |
| if (is_preinitialized_vtable()) { |
| // At runtime initialize_vtable is rerun for a shared class |
| // (loaded by the non-boot loader) as part of link_class_impl(). |
| // The dumptime vtable index should be the same as the runtime index. |
| assert(def_vtable_indices->at(i) == initialized, |
| "dump time vtable index is different from runtime index"); |
| } else { |
| def_vtable_indices->at_put(i, initialized); //set vtable index |
| } |
| initialized++; |
| } |
| } |
| } |
| } |
| |
| // add miranda methods; it will also return the updated initialized |
| // Interfaces do not need interface methods in their vtables |
| // This includes miranda methods and during later processing, default methods |
| if (!ik()->is_interface()) { |
| initialized = fill_in_mirandas(initialized); |
| } |
| |
| // In class hierarchies where the accessibility is not increasing (i.e., going from private -> |
| // package_private -> public/protected), the vtable might actually be smaller than our initial |
| // calculation. |
| assert(initialized <= _length, "vtable initialization failed"); |
| for(;initialized < _length; initialized++) { |
| put_method_at(NULL, initialized); |
| } |
| NOT_PRODUCT(verify(tty, true)); |
| } |
| } |
| |
| // Called for cases where a method does not override its superclass' vtable entry |
| // For bytecodes not produced by javac together it is possible that a method does not override |
| // the superclass's method, but might indirectly override a super-super class's vtable entry |
| // If none found, return a null superk, else return the superk of the method this does override |
| // For public and protected methods: if they override a superclass, they will |
| // also be overridden themselves appropriately. |
| // Private methods do not override and are not overridden. |
| // Package Private methods are trickier: |
| // e.g. P1.A, pub m |
| // P2.B extends A, package private m |
| // P1.C extends B, public m |
| // P1.C.m needs to override P1.A.m and can not override P2.B.m |
| // Therefore: all package private methods need their own vtable entries for |
| // them to be the root of an inheritance overriding decision |
| // Package private methods may also override other vtable entries |
| InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, |
| int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) { |
| InstanceKlass* superk = initialsuper; |
| while (superk != NULL && superk->super() != NULL) { |
| InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super()); |
| klassVtable* ssVtable = supersuperklass->vtable(); |
| if (vtable_index < ssVtable->length()) { |
| Method* super_method = ssVtable->method_at(vtable_index); |
| #ifndef PRODUCT |
| Symbol* name= target_method()->name(); |
| Symbol* signature = target_method()->signature(); |
| assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch"); |
| #endif |
| if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) { |
| #ifndef PRODUCT |
| if (PrintVtables && Verbose) { |
| ResourceMark rm(THREAD); |
| char* sig = target_method()->name_and_sig_as_C_string(); |
| tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ", |
| supersuperklass->internal_name(), |
| _klass->internal_name(), sig, vtable_index); |
| super_method->access_flags().print_on(tty); |
| if (super_method->is_default_method()) { |
| tty->print("default "); |
| } |
| tty->print("overriders flags: "); |
| target_method->access_flags().print_on(tty); |
| if (target_method->is_default_method()) { |
| tty->print("default "); |
| } |
| } |
| #endif /*PRODUCT*/ |
| break; // return found superk |
| } |
| } else { |
| // super class has no vtable entry here, stop transitive search |
| superk = (InstanceKlass*)NULL; |
| break; |
| } |
| // if no override found yet, continue to search up |
| superk = InstanceKlass::cast(superk->super()); |
| } |
| |
| return superk; |
| } |
| |
| // Update child's copy of super vtable for overrides |
| // OR return true if a new vtable entry is required. |
| // Only called for InstanceKlass's, i.e. not for arrays |
| // If that changed, could not use _klass as handle for klass |
| bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, |
| int super_vtable_len, int default_index, |
| bool checkconstraints, TRAPS) { |
| ResourceMark rm; |
| bool allocate_new = true; |
| assert(klass->oop_is_instance(), "must be InstanceKlass"); |
| |
| Array<int>* def_vtable_indices = NULL; |
| bool is_default = false; |
| // default methods are concrete methods in superinterfaces which are added to the vtable |
| // with their real method_holder |
| // Since vtable and itable indices share the same storage, don't touch |
| // the default method's real vtable/itable index |
| // default_vtable_indices stores the vtable value relative to this inheritor |
| if (default_index >= 0 ) { |
| is_default = true; |
| def_vtable_indices = klass->default_vtable_indices(); |
| assert(def_vtable_indices != NULL, "def vtable alloc?"); |
| assert(default_index <= def_vtable_indices->length(), "def vtable len?"); |
| } else { |
| assert(klass == target_method()->method_holder(), "caller resp."); |
| // Initialize the method's vtable index to "nonvirtual". |
| // If we allocate a vtable entry, we will update it to a non-negative number. |
| target_method()->set_vtable_index(Method::nonvirtual_vtable_index); |
| } |
| |
| // Static and <init> methods are never in |
| if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) { |
| return false; |
| } |
| |
| if (target_method->is_final_method(klass->access_flags())) { |
| // a final method never needs a new entry; final methods can be statically |
| // resolved and they have to be present in the vtable only if they override |
| // a super's method, in which case they re-use its entry |
| allocate_new = false; |
| } else if (klass->is_interface()) { |
| allocate_new = false; // see note below in needs_new_vtable_entry |
| // An interface never allocates new vtable slots, only inherits old ones. |
| // This method will either be assigned its own itable index later, |
| // or be assigned an inherited vtable index in the loop below. |
| // default methods inherited by classes store their vtable indices |
| // in the inheritor's default_vtable_indices |
| // default methods inherited by interfaces may already have a |
| // valid itable index, if so, don't change it |
| // overpass methods in an interface will be assigned an itable index later |
| // by an inheriting class |
| if (!is_default || !target_method()->has_itable_index()) { |
| target_method()->set_vtable_index(Method::pending_itable_index); |
| } |
| } |
| |
| // we need a new entry if there is no superclass |
| Klass* super = klass->super(); |
| if (super == NULL) { |
| return allocate_new; |
| } |
| |
| // private methods in classes always have a new entry in the vtable |
| // specification interpretation since classic has |
| // private methods not overriding |
| // JDK8 adds private methods in interfaces which require invokespecial |
| if (target_method()->is_private()) { |
| return allocate_new; |
| } |
| |
| // search through the vtable and update overridden entries |
| // Since check_signature_loaders acquires SystemDictionary_lock |
| // which can block for gc, once we are in this loop, use handles |
| // For classfiles built with >= jdk7, we now look for transitive overrides |
| |
| Symbol* name = target_method()->name(); |
| Symbol* signature = target_method()->signature(); |
| |
| KlassHandle target_klass(THREAD, target_method()->method_holder()); |
| if (target_klass == NULL) { |
| target_klass = _klass; |
| } |
| |
| Handle target_loader(THREAD, target_klass->class_loader()); |
| |
| Symbol* target_classname = target_klass->name(); |
| for(int i = 0; i < super_vtable_len; i++) { |
| Method* super_method; |
| if (is_preinitialized_vtable()) { |
| // If this is a shared class, the vtable is already in the final state (fully |
| // initialized). Need to look at the super's vtable. |
| klassVtable* superVtable = super->vtable(); |
| super_method = superVtable->method_at(i); |
| } else { |
| super_method = method_at(i); |
| } |
| // Check if method name matches |
| if (super_method->name() == name && super_method->signature() == signature) { |
| |
| // get super_klass for method_holder for the found method |
| InstanceKlass* super_klass = super_method->method_holder(); |
| |
| // private methods are also never overridden |
| if (!super_method->is_private() && |
| (is_default |
| || ((super_klass->is_override(super_method, target_loader, target_classname, THREAD)) |
| || ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION) |
| && ((super_klass = find_transitive_override(super_klass, |
| target_method, i, target_loader, |
| target_classname, THREAD)) |
| != (InstanceKlass*)NULL))))) |
| { |
| // Package private methods always need a new entry to root their own |
| // overriding. They may also override other methods. |
| if (!target_method()->is_package_private()) { |
| allocate_new = false; |
| } |
| |
| if (checkconstraints) { |
| // Override vtable entry if passes loader constraint check |
| // if loader constraint checking requested |
| // No need to visit his super, since he and his super |
| // have already made any needed loader constraints. |
| // Since loader constraints are transitive, it is enough |
| // to link to the first super, and we get all the others. |
| Handle super_loader(THREAD, super_klass->class_loader()); |
| |
| if (target_loader() != super_loader()) { |
| ResourceMark rm(THREAD); |
| Symbol* failed_type_symbol = |
| SystemDictionary::check_signature_loaders(signature, target_loader, |
| super_loader, true, |
| CHECK_(false)); |
| if (failed_type_symbol != NULL) { |
| const char* msg = "loader constraint violation: when resolving " |
| "overridden method \"%s\" the class loader (instance" |
| " of %s) of the current class, %s, and its superclass loader " |
| "(instance of %s), have different Class objects for the type " |
| "%s used in the signature"; |
| char* sig = target_method()->name_and_sig_as_C_string(); |
| const char* loader1 = SystemDictionary::loader_name(target_loader()); |
| char* current = target_klass->name()->as_C_string(); |
| const char* loader2 = SystemDictionary::loader_name(super_loader()); |
| char* failed_type_name = failed_type_symbol->as_C_string(); |
| size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) + |
| strlen(current) + strlen(loader2) + strlen(failed_type_name); |
| char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); |
| jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2, |
| failed_type_name); |
| THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false); |
| } |
| } |
| } |
| |
| put_method_at(target_method(), i); |
| if (!is_default) { |
| target_method()->set_vtable_index(i); |
| } else { |
| if (def_vtable_indices != NULL) { |
| if (is_preinitialized_vtable()) { |
| // At runtime initialize_vtable is rerun as part of link_class_impl() |
| // for a shared class loaded by the non-boot loader. |
| // The dumptime vtable index should be the same as the runtime index. |
| assert(def_vtable_indices->at(default_index) == i, |
| "dump time vtable index is different from runtime index"); |
| } else { |
| def_vtable_indices->at_put(default_index, i); |
| } |
| } |
| assert(super_method->is_default_method() || super_method->is_overpass() |
| || super_method->is_abstract(), "default override error"); |
| } |
| |
| |
| #ifndef PRODUCT |
| if (PrintVtables && Verbose) { |
| ResourceMark rm(THREAD); |
| char* sig = target_method()->name_and_sig_as_C_string(); |
| tty->print("overriding with %s::%s index %d, original flags: ", |
| target_klass->internal_name(), sig, i); |
| super_method->access_flags().print_on(tty); |
| if (super_method->is_default_method()) { |
| tty->print("default "); |
| } |
| if (super_method->is_overpass()) { |
| tty->print("overpass"); |
| } |
| tty->print("overriders flags: "); |
| target_method->access_flags().print_on(tty); |
| if (target_method->is_default_method()) { |
| tty->print("default "); |
| } |
| if (target_method->is_overpass()) { |
| tty->print("overpass"); |
| } |
| tty->cr(); |
| } |
| #endif /*PRODUCT*/ |
| } else { |
| // allocate_new = true; default. We might override one entry, |
| // but not override another. Once we override one, not need new |
| #ifndef PRODUCT |
| if (PrintVtables && Verbose) { |
| ResourceMark rm(THREAD); |
| char* sig = target_method()->name_and_sig_as_C_string(); |
| tty->print("NOT overriding with %s::%s index %d, original flags: ", |
| target_klass->internal_name(), sig,i); |
| super_method->access_flags().print_on(tty); |
| if (super_method->is_default_method()) { |
| tty->print("default "); |
| } |
| if (super_method->is_overpass()) { |
| tty->print("overpass"); |
| } |
| tty->print("overriders flags: "); |
| target_method->access_flags().print_on(tty); |
| if (target_method->is_default_method()) { |
| tty->print("default "); |
| } |
| if (target_method->is_overpass()) { |
| tty->print("overpass"); |
| } |
| tty->cr(); |
| } |
| #endif /*PRODUCT*/ |
| } |
| } |
| } |
| return allocate_new; |
| } |
| |
| void klassVtable::put_method_at(Method* m, int index) { |
| if (is_preinitialized_vtable()) { |
| // At runtime initialize_vtable is rerun as part of link_class_impl() |
| // for shared class loaded by the non-boot loader to obtain the loader |
| // constraints based on the runtime classloaders' context. The dumptime |
| // method at the vtable index should be the same as the runtime method. |
| assert(table()[index].method() == m, |
| "archived method is different from the runtime method"); |
| } else { |
| #ifndef PRODUCT |
| if (PrintVtables && Verbose) { |
| ResourceMark rm; |
| const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>"; |
| tty->print("adding %s at index %d, flags: ", sig, index); |
| if (m != NULL) { |
| m->access_flags().print_on(tty); |
| if (m->is_default_method()) { |
| tty->print("default "); |
| } |
| if (m->is_overpass()) { |
| tty->print("overpass"); |
| } |
| } |
| tty->cr(); |
| } |
| #endif |
| table()[index].set(m); |
| } |
| } |
| |
| // Find out if a method "m" with superclass "super", loader "classloader" and |
| // name "classname" needs a new vtable entry. Let P be a class package defined |
| // by "classloader" and "classname". |
| // NOTE: The logic used here is very similar to the one used for computing |
| // the vtables indices for a method. We cannot directly use that function because, |
| // we allocate the InstanceKlass at load time, and that requires that the |
| // superclass has been loaded. |
| // However, the vtable entries are filled in at link time, and therefore |
| // the superclass' vtable may not yet have been filled in. |
| bool klassVtable::needs_new_vtable_entry(methodHandle target_method, |
| Klass* super, |
| Handle classloader, |
| Symbol* classname, |
| AccessFlags class_flags, |
| TRAPS) { |
| if (class_flags.is_interface()) { |
| // Interfaces do not use vtables, except for java.lang.Object methods, |
| // so there is no point to assigning |
| // a vtable index to any of their local methods. If we refrain from doing this, |
| // we can use Method::_vtable_index to hold the itable index |
| return false; |
| } |
| |
| if (target_method->is_final_method(class_flags) || |
| // a final method never needs a new entry; final methods can be statically |
| // resolved and they have to be present in the vtable only if they override |
| // a super's method, in which case they re-use its entry |
| (target_method()->is_static()) || |
| // static methods don't need to be in vtable |
| (target_method()->name() == vmSymbols::object_initializer_name()) |
| // <init> is never called dynamically-bound |
| ) { |
| return false; |
| } |
| |
| // Concrete interface methods do not need new entries, they override |
| // abstract method entries using default inheritance rules |
| if (target_method()->method_holder() != NULL && |
| target_method()->method_holder()->is_interface() && |
| !target_method()->is_abstract() ) { |
| return false; |
| } |
| |
| // we need a new entry if there is no superclass |
| if (super == NULL) { |
| return true; |
| } |
| |
| // private methods in classes always have a new entry in the vtable |
| // specification interpretation since classic has |
| // private methods not overriding |
| // JDK8 adds private methods in interfaces which require invokespecial |
| if (target_method()->is_private()) { |
| return true; |
| } |
| |
| // Package private methods always need a new entry to root their own |
| // overriding. This allows transitive overriding to work. |
| if (target_method()->is_package_private()) { |
| return true; |
| } |
| |
| // search through the super class hierarchy to see if we need |
| // a new entry |
| ResourceMark rm; |
| Symbol* name = target_method()->name(); |
| Symbol* signature = target_method()->signature(); |
| Klass* k = super; |
| Method* super_method = NULL; |
| InstanceKlass *holder = NULL; |
| Method* recheck_method = NULL; |
| while (k != NULL) { |
| // lookup through the hierarchy for a method with matching name and sign. |
| super_method = InstanceKlass::cast(k)->lookup_method(name, signature); |
| if (super_method == NULL) { |
| break; // we still have to search for a matching miranda method |
| } |
| // get the class holding the matching method |
| // make sure you use that class for is_override |
| InstanceKlass* superk = super_method->method_holder(); |
| // we want only instance method matches |
| // pretend private methods are not in the super vtable |
| // since we do override around them: e.g. a.m pub/b.m private/c.m pub, |
| // ignore private, c.m pub does override a.m pub |
| // For classes that were not javac'd together, we also do transitive overriding around |
| // methods that have less accessibility |
| if ((!super_method->is_static()) && |
| (!super_method->is_private())) { |
| if (superk->is_override(super_method, classloader, classname, THREAD)) { |
| return false; |
| // else keep looking for transitive overrides |
| } |
| } |
| |
| // Start with lookup result and continue to search up |
| k = superk->super(); // haven't found an override match yet; continue to look |
| } |
| |
| // if the target method is public or protected it may have a matching |
| // miranda method in the super, whose entry it should re-use. |
| // Actually, to handle cases that javac would not generate, we need |
| // this check for all access permissions. |
| InstanceKlass *sk = InstanceKlass::cast(super); |
| if (sk->has_miranda_methods()) { |
| if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) { |
| return false; // found a matching miranda; we do not need a new entry |
| } |
| } |
| return true; // found no match; we need a new entry |
| } |
| |
| // Support for miranda methods |
| |
| // get the vtable index of a miranda method with matching "name" and "signature" |
| int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) { |
| // search from the bottom, might be faster |
| for (int i = (length() - 1); i >= 0; i--) { |
| Method* m = table()[i].method(); |
| if (is_miranda_entry_at(i) && |
| m->name() == name && m->signature() == signature) { |
| return i; |
| } |
| } |
| return Method::invalid_vtable_index; |
| } |
| |
| // check if an entry at an index is miranda |
| // requires that method m at entry be declared ("held") by an interface. |
| bool klassVtable::is_miranda_entry_at(int i) { |
| Method* m = method_at(i); |
| Klass* method_holder = m->method_holder(); |
| InstanceKlass *mhk = InstanceKlass::cast(method_holder); |
| |
| // miranda methods are public abstract instance interface methods in a class's vtable |
| if (mhk->is_interface()) { |
| assert(m->is_public(), "should be public"); |
| assert(ik()->implements_interface(method_holder) , "this class should implement the interface"); |
| if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super())) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Check if a method is a miranda method, given a class's methods array, |
| // its default_method table and its super class. |
| // "Miranda" means an abstract non-private method that would not be |
| // overridden for the local class. |
| // A "miranda" method should only include non-private interface |
| // instance methods, i.e. not private methods, not static methods, |
| // not default methods (concrete interface methods), not overpass methods. |
| // If a given class already has a local (including overpass) method, a |
| // default method, or any of its superclasses has the same which would have |
| // overridden an abstract method, then this is not a miranda method. |
| // |
| // Miranda methods are checked multiple times. |
| // Pass 1: during class load/class file parsing: before vtable size calculation: |
| // include superinterface abstract and default methods (non-private instance). |
| // We include potential default methods to give them space in the vtable. |
| // During the first run, the current instanceKlass has not yet been |
| // created, the superclasses and superinterfaces do have instanceKlasses |
| // but may not have vtables, the default_methods list is empty, no overpasses. |
| // This is seen by default method creation. |
| // |
| // Pass 2: recalculated during vtable initialization: only include abstract methods. |
| // The goal of pass 2 is to walk through the superinterfaces to see if any of |
| // the superinterface methods (which were all abstract pre-default methods) |
| // need to be added to the vtable. |
| // With the addition of default methods, we have three new challenges: |
| // overpasses, static interface methods and private interface methods. |
| // Static and private interface methods do not get added to the vtable and |
| // are not seen by the method resolution process, so we skip those. |
| // Overpass methods are already in the vtable, so vtable lookup will |
| // find them and we don't need to add a miranda method to the end of |
| // the vtable. So we look for overpass methods and if they are found we |
| // return false. Note that we inherit our superclasses vtable, so |
| // the superclass' search also needs to use find_overpass so that if |
| // one is found we return false. |
| // False means - we don't need a miranda method added to the vtable. |
| // |
| // During the second run, default_methods is set up, so concrete methods from |
| // superinterfaces with matching names/signatures to default_methods are already |
| // in the default_methods list and do not need to be appended to the vtable |
| // as mirandas. Abstract methods may already have been handled via |
| // overpasses - either local or superclass overpasses, which may be |
| // in the vtable already. |
| // |
| // Pass 3: They are also checked by link resolution and selection, |
| // for invocation on a method (not interface method) reference that |
| // resolves to a method with an interface as its method_holder. |
| // Used as part of walking from the bottom of the vtable to find |
| // the vtable index for the miranda method. |
| // |
| // Part of the Miranda Rights in the US mean that if you do not have |
| // an attorney one will be appointed for you. |
| bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, |
| Array<Method*>* default_methods, Klass* super) { |
| if (m->is_static() || m->is_private() || m->is_overpass()) { |
| return false; |
| } |
| Symbol* name = m->name(); |
| Symbol* signature = m->signature(); |
| |
| // First look in local methods to see if already covered |
| if (InstanceKlass::find_local_method(class_methods, name, signature, |
| Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL) |
| { |
| return false; |
| } |
| |
| // Check local default methods |
| if ((default_methods != NULL) && |
| (InstanceKlass::find_method(default_methods, name, signature) != NULL)) |
| { |
| return false; |
| } |
| |
| InstanceKlass* cursuper; |
| // Iterate on all superclasses, which should have instanceKlasses |
| // Note that we explicitly look for overpasses at each level. |
| // Overpasses may or may not exist for supers for pass 1, |
| // they should have been created for pass 2 and later. |
| |
| for (cursuper = InstanceKlass::cast(super); cursuper != NULL; cursuper = (InstanceKlass*)cursuper->super()) |
| { |
| if (cursuper->find_local_method(name, signature, |
| Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| // Scans current_interface_methods for miranda methods that do not |
| // already appear in new_mirandas, or default methods, and are also not defined-and-non-private |
| // in super (superclass). These mirandas are added to all_mirandas if it is |
| // not null; in addition, those that are not duplicates of miranda methods |
| // inherited by super from its interfaces are added to new_mirandas. |
| // Thus, new_mirandas will be the set of mirandas that this class introduces, |
| // all_mirandas will be the set of all mirandas applicable to this class |
| // including all defined in superclasses. |
| void klassVtable::add_new_mirandas_to_lists( |
| GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas, |
| Array<Method*>* current_interface_methods, Array<Method*>* class_methods, |
| Array<Method*>* default_methods, Klass* super) { |
| |
| // iterate thru the current interface's method to see if it a miranda |
| int num_methods = current_interface_methods->length(); |
| for (int i = 0; i < num_methods; i++) { |
| Method* im = current_interface_methods->at(i); |
| bool is_duplicate = false; |
| int num_of_current_mirandas = new_mirandas->length(); |
| // check for duplicate mirandas in different interfaces we implement |
| for (int j = 0; j < num_of_current_mirandas; j++) { |
| Method* miranda = new_mirandas->at(j); |
| if ((im->name() == miranda->name()) && |
| (im->signature() == miranda->signature())) { |
| is_duplicate = true; |
| break; |
| } |
| } |
| |
| if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable |
| if (is_miranda(im, class_methods, default_methods, super)) { // is it a miranda at all? |
| InstanceKlass *sk = InstanceKlass::cast(super); |
| // check if it is a duplicate of a super's miranda |
| if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::find_defaults) == NULL) { |
| new_mirandas->append(im); |
| } |
| if (all_mirandas != NULL) { |
| all_mirandas->append(im); |
| } |
| } |
| } |
| } |
| } |
| |
| void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas, |
| GrowableArray<Method*>* all_mirandas, |
| Klass* super, Array<Method*>* class_methods, |
| Array<Method*>* default_methods, |
| Array<Klass*>* local_interfaces) { |
| assert((new_mirandas->length() == 0) , "current mirandas must be 0"); |
| |
| // iterate thru the local interfaces looking for a miranda |
| int num_local_ifs = local_interfaces->length(); |
| for (int i = 0; i < num_local_ifs; i++) { |
| InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i)); |
| add_new_mirandas_to_lists(new_mirandas, all_mirandas, |
| ik->methods(), class_methods, |
| default_methods, super); |
| // iterate thru each local's super interfaces |
| Array<Klass*>* super_ifs = ik->transitive_interfaces(); |
| int num_super_ifs = super_ifs->length(); |
| for (int j = 0; j < num_super_ifs; j++) { |
| InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j)); |
| add_new_mirandas_to_lists(new_mirandas, all_mirandas, |
| sik->methods(), class_methods, |
| default_methods, super); |
| } |
| } |
| } |
| |
| // Discover miranda methods ("miranda" = "interface abstract, no binding"), |
| // and append them into the vtable starting at index initialized, |
| // return the new value of initialized. |
| // Miranda methods use vtable entries, but do not get assigned a vtable_index |
| // The vtable_index is discovered by searching from the end of the vtable |
| int klassVtable::fill_in_mirandas(int initialized) { |
| GrowableArray<Method*> mirandas(20); |
| get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(), |
| ik()->default_methods(), ik()->local_interfaces()); |
| for (int i = 0; i < mirandas.length(); i++) { |
| if (PrintVtables && Verbose) { |
| Method* meth = mirandas.at(i); |
| ResourceMark rm(Thread::current()); |
| if (meth != NULL) { |
| char* sig = meth->name_and_sig_as_C_string(); |
| tty->print("fill in mirandas with %s index %d, flags: ", |
| sig, initialized); |
| meth->access_flags().print_on(tty); |
| if (meth->is_default_method()) { |
| tty->print("default "); |
| } |
| tty->cr(); |
| } |
| } |
| put_method_at(mirandas.at(i), initialized); |
| ++initialized; |
| } |
| return initialized; |
| } |
| |
| // Copy this class's vtable to the vtable beginning at start. |
| // Used to copy superclass vtable to prefix of subclass's vtable. |
| void klassVtable::copy_vtable_to(vtableEntry* start) { |
| Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size()); |
| } |
| |
| #if INCLUDE_JVMTI |
| bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) { |
| // If old_method is default, find this vtable index in default_vtable_indices |
| // and replace that method in the _default_methods list |
| bool updated = false; |
| |
| Array<Method*>* default_methods = ik()->default_methods(); |
| if (default_methods != NULL) { |
| int len = default_methods->length(); |
| for (int idx = 0; idx < len; idx++) { |
| if (vtable_index == ik()->default_vtable_indices()->at(idx)) { |
| if (default_methods->at(idx) == old_method) { |
| default_methods->at_put(idx, new_method); |
| updated = true; |
| } |
| break; |
| } |
| } |
| } |
| return updated; |
| } |
| |
| // search the vtable for uses of either obsolete or EMCP methods |
| void klassVtable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) { |
| int prn_enabled = 0; |
| for (int index = 0; index < length(); index++) { |
| Method* old_method = unchecked_method_at(index); |
| if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) { |
| continue; // skip uninteresting entries |
| } |
| assert(!old_method->is_deleted(), "vtable methods may not be deleted"); |
| |
| Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum()); |
| |
| assert(new_method != NULL, "method_with_idnum() should not be NULL"); |
| assert(old_method != new_method, "sanity check"); |
| |
| put_method_at(new_method, index); |
| // For default methods, need to update the _default_methods array |
| // which can only have one method entry for a given signature |
| bool updated_default = false; |
| if (old_method->is_default_method()) { |
| updated_default = adjust_default_method(index, old_method, new_method); |
| } |
| |
| if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { |
| if (!(*trace_name_printed)) { |
| // RC_TRACE_MESG macro has an embedded ResourceMark |
| RC_TRACE_MESG(("adjust: klassname=%s for methods from name=%s", |
| klass()->external_name(), |
| old_method->method_holder()->external_name())); |
| *trace_name_printed = true; |
| } |
| // RC_TRACE macro has an embedded ResourceMark |
| RC_TRACE(0x00100000, ("vtable method update: %s(%s), updated default = %s", |
| new_method->name()->as_C_string(), |
| new_method->signature()->as_C_string(), |
| updated_default ? "true" : "false")); |
| } |
| } |
| } |
| |
| // a vtable should never contain old or obsolete methods |
| bool klassVtable::check_no_old_or_obsolete_entries() { |
| for (int i = 0; i < length(); i++) { |
| Method* m = unchecked_method_at(i); |
| if (m != NULL && |
| (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| void klassVtable::dump_vtable() { |
| tty->print_cr("vtable dump --"); |
| for (int i = 0; i < length(); i++) { |
| Method* m = unchecked_method_at(i); |
| if (m != NULL) { |
| tty->print(" (%5d) ", i); |
| m->access_flags().print_on(tty); |
| if (m->is_default_method()) { |
| tty->print("default "); |
| } |
| if (m->is_overpass()) { |
| tty->print("overpass"); |
| } |
| tty->print(" -- "); |
| m->print_name(tty); |
| tty->cr(); |
| } |
| } |
| } |
| #endif // INCLUDE_JVMTI |
| |
| // CDS/RedefineClasses support - clear vtables so they can be reinitialized |
| void klassVtable::clear_vtable() { |
| for (int i = 0; i < _length; i++) table()[i].clear(); |
| } |
| |
| bool klassVtable::is_initialized() { |
| return _length == 0 || table()[0].method() != NULL; |
| } |
| |
| //----------------------------------------------------------------------------------------- |
| // Itable code |
| |
| // Initialize a itableMethodEntry |
| void itableMethodEntry::initialize(Method* m) { |
| if (m == NULL) return; |
| |
| if (MetaspaceShared::is_in_shared_space((void*)&_method) && |
| !MetaspaceShared::remapped_readwrite()) { |
| // At runtime initialize_itable is rerun as part of link_class_impl() |
| // for a shared class loaded by the non-boot loader. |
| // The dumptime itable method entry should be the same as the runtime entry. |
| assert(_method == m, "sanity"); |
| } else { |
| _method = m; |
| } |
| } |
| |
| klassItable::klassItable(instanceKlassHandle klass) { |
| _klass = klass; |
| |
| if (klass->itable_length() > 0) { |
| itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable(); |
| if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized |
| // First offset entry points to the first method_entry |
| intptr_t* method_entry = (intptr_t *)(((address)klass()) + offset_entry->offset()); |
| intptr_t* end = klass->end_of_itable(); |
| |
| _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass(); |
| _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size(); |
| _size_method_table = (end - method_entry) / itableMethodEntry::size(); |
| assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation"); |
| return; |
| } |
| } |
| |
| // The length of the itable was either zero, or it has not yet been initialized. |
| _table_offset = 0; |
| _size_offset_table = 0; |
| _size_method_table = 0; |
| } |
| |
| static int initialize_count = 0; |
| |
| // Initialization |
| void klassItable::initialize_itable(bool checkconstraints, TRAPS) { |
| if (_klass->is_interface()) { |
| // This needs to go after vtable indices are assigned but |
| // before implementors need to know the number of itable indices. |
| assign_itable_indices_for_interface(_klass()); |
| } |
| |
| // Cannot be setup doing bootstrapping, interfaces don't have |
| // itables, and klass with only ones entry have empty itables |
| if (Universe::is_bootstrapping() || |
| _klass->is_interface() || |
| _klass->itable_length() == itableOffsetEntry::size()) return; |
| |
| // There's alway an extra itable entry so we can null-terminate it. |
| guarantee(size_offset_table() >= 1, "too small"); |
| int num_interfaces = size_offset_table() - 1; |
| if (num_interfaces > 0) { |
| if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count, |
| _klass->name()->as_C_string()); |
| |
| |
| // Iterate through all interfaces |
| int i; |
| for(i = 0; i < num_interfaces; i++) { |
| itableOffsetEntry* ioe = offset_entry(i); |
| HandleMark hm(THREAD); |
| KlassHandle interf_h (THREAD, ioe->interface_klass()); |
| assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable"); |
| initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK); |
| } |
| |
| } |
| // Check that the last entry is empty |
| itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1); |
| guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing"); |
| } |
| |
| |
| inline bool interface_method_needs_itable_index(Method* m) { |
| if (m->is_static()) return false; // e.g., Stream.empty |
| if (m->is_initializer()) return false; // <init> or <clinit> |
| // If an interface redeclares a method from java.lang.Object, |
| // it should already have a vtable index, don't touch it. |
| // e.g., CharSequence.toString (from initialize_vtable) |
| // if (m->has_vtable_index()) return false; // NO! |
| return true; |
| } |
| |
| int klassItable::assign_itable_indices_for_interface(Klass* klass) { |
| // an interface does not have an itable, but its methods need to be numbered |
| if (TraceItables) tty->print_cr("%3d: Initializing itable for interface %s", ++initialize_count, |
| klass->name()->as_C_string()); |
| Array<Method*>* methods = InstanceKlass::cast(klass)->methods(); |
| int nof_methods = methods->length(); |
| int ime_num = 0; |
| for (int i = 0; i < nof_methods; i++) { |
| Method* m = methods->at(i); |
| if (interface_method_needs_itable_index(m)) { |
| assert(!m->is_final_method(), "no final interface methods"); |
| // If m is already assigned a vtable index, do not disturb it. |
| if (TraceItables && Verbose) { |
| ResourceMark rm; |
| const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>"; |
| if (m->has_vtable_index()) { |
| tty->print("itable index %d for method: %s, flags: ", m->vtable_index(), sig); |
| } else { |
| tty->print("itable index %d for method: %s, flags: ", ime_num, sig); |
| } |
| if (m != NULL) { |
| m->access_flags().print_on(tty); |
| if (m->is_default_method()) { |
| tty->print("default "); |
| } |
| if (m->is_overpass()) { |
| tty->print("overpass"); |
| } |
| } |
| tty->cr(); |
| } |
| if (!m->has_vtable_index()) { |
| // A shared method could have an initialized itable_index that |
| // is < 0. |
| assert(m->vtable_index() == Method::pending_itable_index || |
| m->is_shared(), |
| "set by initialize_vtable"); |
| m->set_itable_index(ime_num); |
| // Progress to next itable entry |
| ime_num++; |
| } |
| } |
| } |
| assert(ime_num == method_count_for_interface(klass), "proper sizing"); |
| return ime_num; |
| } |
| |
| int klassItable::method_count_for_interface(Klass* interf) { |
| assert(interf->oop_is_instance(), "must be"); |
| assert(interf->is_interface(), "must be"); |
| Array<Method*>* methods = InstanceKlass::cast(interf)->methods(); |
| int nof_methods = methods->length(); |
| while (nof_methods > 0) { |
| Method* m = methods->at(nof_methods-1); |
| if (m->has_itable_index()) { |
| int length = m->itable_index() + 1; |
| #ifdef ASSERT |
| while (nof_methods = 0) { |
| m = methods->at(--nof_methods); |
| assert(!m->has_itable_index() || m->itable_index() < length, ""); |
| } |
| #endif //ASSERT |
| return length; // return the rightmost itable index, plus one |
| } |
| nof_methods -= 1; |
| } |
| // no methods have itable indices |
| return 0; |
| } |
| |
| |
| void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) { |
| Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods(); |
| int nof_methods = methods->length(); |
| HandleMark hm; |
| assert(nof_methods > 0, "at least one method must exist for interface to be in vtable"); |
| Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader()); |
| |
| int ime_count = method_count_for_interface(interf_h()); |
| for (int i = 0; i < nof_methods; i++) { |
| Method* m = methods->at(i); |
| methodHandle target; |
| if (m->has_itable_index()) { |
| // This search must match the runtime resolution, i.e. selection search for invokeinterface |
| // to correctly enforce loader constraints for interface method inheritance |
| LinkResolver::lookup_instance_method_in_klasses(target, _klass, m->name(), m->signature(), CHECK); |
| } |
| if (target == NULL || !target->is_public() || target->is_abstract()) { |
| // Entry does not resolve. Leave it empty for AbstractMethodError. |
| if (!(target == NULL) && !target->is_public()) { |
| // Stuff an IllegalAccessError throwing method in there instead. |
| itableOffsetEntry::method_entry(_klass(), method_table_offset)[m->itable_index()]. |
| initialize(Universe::throw_illegal_access_error()); |
| } |
| } else { |
| // Entry did resolve, check loader constraints before initializing |
| // if checkconstraints requested |
| if (checkconstraints) { |
| Handle method_holder_loader (THREAD, target->method_holder()->class_loader()); |
| if (method_holder_loader() != interface_loader()) { |
| ResourceMark rm(THREAD); |
| Symbol* failed_type_symbol = |
| SystemDictionary::check_signature_loaders(m->signature(), |
| method_holder_loader, |
| interface_loader, |
| true, CHECK); |
| if (failed_type_symbol != NULL) { |
| const char* msg = "loader constraint violation in interface " |
| "itable initialization: when resolving method \"%s\" the class" |
| " loader (instance of %s) of the current class, %s, " |
| "and the class loader (instance of %s) for interface " |
| "%s have different Class objects for the type %s " |
| "used in the signature"; |
| char* sig = target()->name_and_sig_as_C_string(); |
| const char* loader1 = SystemDictionary::loader_name(method_holder_loader()); |
| char* current = _klass->name()->as_C_string(); |
| const char* loader2 = SystemDictionary::loader_name(interface_loader()); |
| char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string(); |
| char* failed_type_name = failed_type_symbol->as_C_string(); |
| size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) + |
| strlen(current) + strlen(loader2) + strlen(iface) + |
| strlen(failed_type_name); |
| char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); |
| jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2, |
| iface, failed_type_name); |
| THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); |
| } |
| } |
| } |
| |
| // ime may have moved during GC so recalculate address |
| int ime_num = m->itable_index(); |
| assert(ime_num < ime_count, "oob"); |
| itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target()); |
| if (TraceItables && Verbose) { |
| ResourceMark rm(THREAD); |
| if (target() != NULL) { |
| char* sig = target()->name_and_sig_as_C_string(); |
| tty->print("interface: %s, ime_num: %d, target: %s, method_holder: %s ", |
| interf_h()->internal_name(), ime_num, sig, |
| target()->method_holder()->internal_name()); |
| tty->print("target_method flags: "); |
| target()->access_flags().print_on(tty); |
| if (target()->is_default_method()) { |
| tty->print("default "); |
| } |
| tty->cr(); |
| } |
| } |
| } |
| } |
| } |
| |
| // Update entry for specific Method* |
| void klassItable::initialize_with_method(Method* m) { |
| itableMethodEntry* ime = method_entry(0); |
| for(int i = 0; i < _size_method_table; i++) { |
| if (ime->method() == m) { |
| ime->initialize(m); |
| } |
| ime++; |
| } |
| } |
| |
| #if INCLUDE_JVMTI |
| // search the itable for uses of either obsolete or EMCP methods |
| void klassItable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) { |
| |
| itableMethodEntry* ime = method_entry(0); |
| for (int i = 0; i < _size_method_table; i++, ime++) { |
| Method* old_method = ime->method(); |
| if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) { |
| continue; // skip uninteresting entries |
| } |
| assert(!old_method->is_deleted(), "itable methods may not be deleted"); |
| |
| Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum()); |
| |
| assert(new_method != NULL, "method_with_idnum() should not be NULL"); |
| assert(old_method != new_method, "sanity check"); |
| |
| ime->initialize(new_method); |
| |
| if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { |
| if (!(*trace_name_printed)) { |
| // RC_TRACE_MESG macro has an embedded ResourceMark |
| RC_TRACE_MESG(("adjust: name=%s", |
| old_method->method_holder()->external_name())); |
| *trace_name_printed = true; |
| } |
| // RC_TRACE macro has an embedded ResourceMark |
| RC_TRACE(0x00200000, ("itable method update: %s(%s)", |
| new_method->name()->as_C_string(), |
| new_method->signature()->as_C_string())); |
| } |
| } |
| } |
| |
| // an itable should never contain old or obsolete methods |
| bool klassItable::check_no_old_or_obsolete_entries() { |
| itableMethodEntry* ime = method_entry(0); |
| for (int i = 0; i < _size_method_table; i++) { |
| Method* m = ime->method(); |
| if (m != NULL && |
| (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) { |
| return false; |
| } |
| ime++; |
| } |
| return true; |
| } |
| |
| void klassItable::dump_itable() { |
| itableMethodEntry* ime = method_entry(0); |
| tty->print_cr("itable dump --"); |
| for (int i = 0; i < _size_method_table; i++) { |
| Method* m = ime->method(); |
| if (m != NULL) { |
| tty->print(" (%5d) ", i); |
| m->access_flags().print_on(tty); |
| if (m->is_default_method()) { |
| tty->print("default "); |
| } |
| tty->print(" -- "); |
| m->print_name(tty); |
| tty->cr(); |
| } |
| ime++; |
| } |
| } |
| #endif // INCLUDE_JVMTI |
| |
| // Setup |
| class InterfaceVisiterClosure : public StackObj { |
| public: |
| virtual void doit(Klass* intf, int method_count) = 0; |
| }; |
| |
| // Visit all interfaces with at least one itable method |
| void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) { |
| // Handle array argument |
| for(int i = 0; i < transitive_intf->length(); i++) { |
| Klass* intf = transitive_intf->at(i); |
| assert(intf->is_interface(), "sanity check"); |
| |
| // Find no. of itable methods |
| int method_count = 0; |
| // method_count = klassItable::method_count_for_interface(intf); |
| Array<Method*>* methods = InstanceKlass::cast(intf)->methods(); |
| if (methods->length() > 0) { |
| for (int i = methods->length(); --i >= 0; ) { |
| if (interface_method_needs_itable_index(methods->at(i))) { |
| method_count++; |
| } |
| } |
| } |
| |
| // Only count interfaces with at least one method |
| if (method_count > 0) { |
| blk->doit(intf, method_count); |
| } |
| } |
| } |
| |
| class CountInterfacesClosure : public InterfaceVisiterClosure { |
| private: |
| int _nof_methods; |
| int _nof_interfaces; |
| public: |
| CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; } |
| |
| int nof_methods() const { return _nof_methods; } |
| int nof_interfaces() const { return _nof_interfaces; } |
| |
| void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; } |
| }; |
| |
| class SetupItableClosure : public InterfaceVisiterClosure { |
| private: |
| itableOffsetEntry* _offset_entry; |
| itableMethodEntry* _method_entry; |
| address _klass_begin; |
| public: |
| SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) { |
| _klass_begin = klass_begin; |
| _offset_entry = offset_entry; |
| _method_entry = method_entry; |
| } |
| |
| itableMethodEntry* method_entry() const { return _method_entry; } |
| |
| void doit(Klass* intf, int method_count) { |
| int offset = ((address)_method_entry) - _klass_begin; |
| _offset_entry->initialize(intf, offset); |
| _offset_entry++; |
| _method_entry += method_count; |
| } |
| }; |
| |
| int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) { |
| // Count no of interfaces and total number of interface methods |
| CountInterfacesClosure cic; |
| visit_all_interfaces(transitive_interfaces, &cic); |
| |
| // There's alway an extra itable entry so we can null-terminate it. |
| int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods()); |
| |
| // Statistics |
| update_stats(itable_size * HeapWordSize); |
| |
| return itable_size; |
| } |
| |
| |
| // Fill out offset table and interface klasses into the itable space |
| void klassItable::setup_itable_offset_table(instanceKlassHandle klass) { |
| if (klass->itable_length() == 0) return; |
| assert(!klass->is_interface(), "Should have zero length itable"); |
| |
| // Count no of interfaces and total number of interface methods |
| CountInterfacesClosure cic; |
| visit_all_interfaces(klass->transitive_interfaces(), &cic); |
| int nof_methods = cic.nof_methods(); |
| int nof_interfaces = cic.nof_interfaces(); |
| |
| // Add one extra entry so we can null-terminate the table |
| nof_interfaces++; |
| |
| assert(compute_itable_size(klass->transitive_interfaces()) == |
| calc_itable_size(nof_interfaces, nof_methods), |
| "mismatch calculation of itable size"); |
| |
| // Fill-out offset table |
| itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable(); |
| itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces); |
| intptr_t* end = klass->end_of_itable(); |
| assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)"); |
| assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)"); |
| |
| // Visit all interfaces and initialize itable offset table |
| SetupItableClosure sic((address)klass(), ioe, ime); |
| visit_all_interfaces(klass->transitive_interfaces(), &sic); |
| |
| #ifdef ASSERT |
| ime = sic.method_entry(); |
| oop* v = (oop*) klass->end_of_itable(); |
| assert( (oop*)(ime) == v, "wrong offset calculation (2)"); |
| #endif |
| } |
| |
| |
| // inverse to itable_index |
| Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) { |
| assert(InstanceKlass::cast(intf)->is_interface(), "sanity check"); |
| assert(intf->verify_itable_index(itable_index), ""); |
| Array<Method*>* methods = InstanceKlass::cast(intf)->methods(); |
| |
| if (itable_index < 0 || itable_index >= method_count_for_interface(intf)) |
| return NULL; // help caller defend against bad indices |
| |
| int index = itable_index; |
| Method* m = methods->at(index); |
| int index2 = -1; |
| while (!m->has_itable_index() || |
| (index2 = m->itable_index()) != itable_index) { |
| assert(index2 < itable_index, "monotonic"); |
| if (++index == methods->length()) |
| return NULL; |
| m = methods->at(index); |
| } |
| assert(m->itable_index() == itable_index, "correct inverse"); |
| |
| return m; |
| } |
| |
| void klassVtable::verify(outputStream* st, bool forced) { |
| // make sure table is initialized |
| if (!Universe::is_fully_initialized()) return; |
| #ifndef PRODUCT |
| // avoid redundant verifies |
| if (!forced && _verify_count == Universe::verify_count()) return; |
| _verify_count = Universe::verify_count(); |
| #endif |
| oop* end_of_obj = (oop*)_klass() + _klass()->size(); |
| oop* end_of_vtable = (oop *)&table()[_length]; |
| if (end_of_vtable > end_of_obj) { |
| fatal(err_msg("klass %s: klass object too short (vtable extends beyond " |
| "end)", _klass->internal_name())); |
| } |
| |
| for (int i = 0; i < _length; i++) table()[i].verify(this, st); |
| // verify consistency with superKlass vtable |
| Klass* super = _klass->super(); |
| if (super != NULL) { |
| InstanceKlass* sk = InstanceKlass::cast(super); |
| klassVtable* vt = sk->vtable(); |
| for (int i = 0; i < vt->length(); i++) { |
| verify_against(st, vt, i); |
| } |
| } |
| } |
| |
| void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) { |
| vtableEntry* vte = &vt->table()[index]; |
| if (vte->method()->name() != table()[index].method()->name() || |
| vte->method()->signature() != table()[index].method()->signature()) { |
| fatal("mismatched name/signature of vtable entries"); |
| } |
| } |
| |
| #ifndef PRODUCT |
| void klassVtable::print() { |
| ResourceMark rm; |
| tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length()); |
| for (int i = 0; i < length(); i++) { |
| table()[i].print(); |
| tty->cr(); |
| } |
| } |
| #endif |
| |
| void vtableEntry::verify(klassVtable* vt, outputStream* st) { |
| NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true)); |
| assert(method() != NULL, "must have set method"); |
| method()->verify(); |
| // we sub_type, because it could be a miranda method |
| if (!vt->klass()->is_subtype_of(method()->method_holder())) { |
| #ifndef PRODUCT |
| print(); |
| #endif |
| fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this)); |
| } |
| } |
| |
| #ifndef PRODUCT |
| |
| void vtableEntry::print() { |
| ResourceMark rm; |
| tty->print("vtableEntry %s: ", method()->name()->as_C_string()); |
| if (Verbose) { |
| tty->print("m %#lx ", (address)method()); |
| } |
| } |
| |
| class VtableStats : AllStatic { |
| public: |
| static int no_klasses; // # classes with vtables |
| static int no_array_klasses; // # array classes |
| static int no_instance_klasses; // # instanceKlasses |
| static int sum_of_vtable_len; // total # of vtable entries |
| static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only |
| static int fixed; // total fixed overhead in bytes |
| static int filler; // overhead caused by filler bytes |
| static int entries; // total bytes consumed by vtable entries |
| static int array_entries; // total bytes consumed by array vtable entries |
| |
| static void do_class(Klass* k) { |
| Klass* kl = k; |
| klassVtable* vt = kl->vtable(); |
| if (vt == NULL) return; |
| no_klasses++; |
| if (kl->oop_is_instance()) { |
| no_instance_klasses++; |
| kl->array_klasses_do(do_class); |
| } |
| if (kl->oop_is_array()) { |
| no_array_klasses++; |
| sum_of_array_vtable_len += vt->length(); |
| } |
| sum_of_vtable_len += vt->length(); |
| } |
| |
| static void compute() { |
| SystemDictionary::classes_do(do_class); |
| fixed = no_klasses * oopSize; // vtable length |
| // filler size is a conservative approximation |
| filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1); |
| entries = sizeof(vtableEntry) * sum_of_vtable_len; |
| array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len; |
| } |
| }; |
| |
| int VtableStats::no_klasses = 0; |
| int VtableStats::no_array_klasses = 0; |
| int VtableStats::no_instance_klasses = 0; |
| int VtableStats::sum_of_vtable_len = 0; |
| int VtableStats::sum_of_array_vtable_len = 0; |
| int VtableStats::fixed = 0; |
| int VtableStats::filler = 0; |
| int VtableStats::entries = 0; |
| int VtableStats::array_entries = 0; |
| |
| void klassVtable::print_statistics() { |
| ResourceMark rm; |
| HandleMark hm; |
| VtableStats::compute(); |
| tty->print_cr("vtable statistics:"); |
| tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses); |
| int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries; |
| tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed); |
| tty->print_cr("%6d bytes filler overhead", VtableStats::filler); |
| tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries); |
| tty->print_cr("%6d bytes total", total); |
| } |
| |
| int klassItable::_total_classes; // Total no. of classes with itables |
| long klassItable::_total_size; // Total no. of bytes used for itables |
| |
| void klassItable::print_statistics() { |
| tty->print_cr("itable statistics:"); |
| tty->print_cr("%6d classes with itables", _total_classes); |
| tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes); |
| } |
| |
| #endif // PRODUCT |
