/* * Copyright 1997-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ #include "incls/_precompiled.incl" #include "incls/_klassVtable.cpp.incl" inline instanceKlass* klassVtable::ik() const { Klass* k = _klass()->klass_part(); assert(k->oop_is_instance(), "not an instanceKlass"); return (instanceKlass*)k; } // 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. Let's say there is a 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, int &num_miranda_methods, klassOop super, objArrayOop methods, AccessFlags class_flags, oop classloader, symbolOop classname, objArrayOop local_interfaces ) { No_Safepoint_Verifier nsv; // set up default result values vtable_length = 0; num_miranda_methods = 0; // start off with super's vtable length instanceKlass* sk = (instanceKlass*)super->klass_part(); 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->obj_at(i)->is_method(), "must be a methodOop"); methodOop m = methodOop(methods->obj_at(i)); if (needs_new_vtable_entry(m, super, classloader, classname, class_flags)) { vtable_length += vtableEntry::size(); // we need a new entry } } // compute the number of mirandas methods that must be added to the end num_miranda_methods = get_num_mirandas(super, methods, local_interfaces); vtable_length += (num_miranda_methods * 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"); } int klassVtable::index_of(methodOop m, int len) const { assert(m->vtable_index() >= 0, "do not ask this of non-vtable methods"); return m->vtable_index(); } int klassVtable::initialize_from_super(KlassHandle super) { if (super.is_null()) { return 0; } 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()->klass_part(); 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) { 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 (Kestral 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; 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()) { // 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"); objArrayHandle methods(THREAD, ik()->methods()); int len = methods()->length(); int initialized = super_vtable_len; // update_super_vtable can stop for gc - ensure using handles for (int i = 0; i < len; i++) { HandleMark hm(THREAD); assert(methods()->obj_at(i)->is_method(), "must be a methodOop"); methodHandle mh(THREAD, (methodOop)methods()->obj_at(i)); bool needs_new_entry = update_super_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK); if (needs_new_entry) { put_method_at(mh(), initialized); mh()->set_vtable_index(initialized); // set primary vtable index initialized++; } } // add miranda methods; it will also update the value of initialized fill_in_mirandas(initialized); // In class hierachieswhere the accesibility is not increasing (i.e., going from private -> // package_private -> publicprotected), 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)); } } // Interates through the vtables to find the broadest access level. This // will always be monotomic for valid Java programs - but not neccesarily // for incompatible class files. klassVtable::AccessType klassVtable::vtable_accessibility_at(int i) { // This vtable is not implementing the specific method if (i >= length()) return acc_private; // Compute AccessType for current method. public or protected we are done. methodOop m = method_at(i); if (m->is_protected() || m->is_public()) return acc_publicprotected; AccessType acc = m->is_package_private() ? acc_package_private : acc_private; // Compute AccessType for method in super classes klassOop super = klass()->super(); AccessType super_acc = (super != NULL) ? instanceKlass::cast(klass()->super())->vtable()->vtable_accessibility_at(i) : acc_private; // Merge return (AccessType)MAX2((int)acc, (int)super_acc); } // 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_super_vtable(instanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS) { ResourceMark rm; bool allocate_new = true; assert(klass->oop_is_instance(), "must be instanceKlass"); // 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(methodOopDesc::nonvirtual_vtable_index); // Static and methods are never in if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) { return false; } if (klass->is_final() || target_method()->is_final()) { // 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; } // we need a new entry if there is no superclass if (klass->super() == NULL) { return allocate_new; } // private methods always have a new entry in the vtable 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, not // unhandled oops unless they are reinitialized for each loop // handles for name, signature, klass, target_method // not for match_method, holder symbolHandle name(THREAD,target_method()->name()); symbolHandle signature(THREAD,target_method()->signature()); for(int i = 0; i < super_vtable_len; i++) { methodOop match_method = method_at(i); // Check if method name matches if (match_method->name() == name() && match_method->signature() == signature()) { instanceKlass* holder = (THREAD, instanceKlass::cast(match_method->method_holder())); // Check if the match_method is accessable from current class bool same_package_init = false; bool same_package_flag = false; bool simple_match = match_method->is_public() || match_method->is_protected(); if (!simple_match) { same_package_init = true; same_package_flag = holder->is_same_class_package(_klass->class_loader(), _klass->name()); simple_match = match_method->is_package_private() && same_package_flag; } // match_method is the superclass' method. Note we can't override // and shouldn't access superclass' ACC_PRIVATE methods // (although they have been copied into our vtable) // A simple form of this statement is: // if ( (match_method->is_public() || match_method->is_protected()) || // (match_method->is_package_private() && holder->is_same_class_package(klass->class_loader(), klass->name()))) { // // The complexity is introduced it avoid recomputing 'is_same_class_package' which is expensive. if (simple_match) { // Check if target_method and match_method has same level of accessibility. The accesibility of the // match method is the "most-general" visibility of all entries at it's particular vtable index for // all superclasses. This check must be done before we override the current entry in the vtable. AccessType at = vtable_accessibility_at(i); bool same_access = false; if ( (at == acc_publicprotected && (target_method()->is_public() || target_method()->is_protected()) || (at == acc_package_private && (target_method()->is_package_private() && (( same_package_init && same_package_flag) || (!same_package_init && holder->is_same_class_package(_klass->class_loader(), _klass->name()))))))) { same_access = true; } 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. symbolHandle signature(THREAD, target_method()->signature()); Handle this_loader(THREAD, _klass->class_loader()); instanceKlassHandle super_klass(THREAD, _klass->super()); Handle super_loader(THREAD, super_klass->class_loader()); if (this_loader() != super_loader()) { ResourceMark rm(THREAD); char* failed_type_name = SystemDictionary::check_signature_loaders(signature, this_loader, super_loader, true, CHECK_(false)); if (failed_type_name != 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(this_loader()); char* current = _klass->name()->as_C_string(); const char* loader2 = SystemDictionary::loader_name(super_loader()); 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 (same_access) { // target and match has same accessiblity - share entry allocate_new = false; target_method()->set_vtable_index(i); #ifndef PRODUCT if (PrintVtables && Verbose) { AccessType targetacc; if (target_method()->is_protected() || target_method()->is_public()) { targetacc = acc_publicprotected; } else { targetacc = target_method()->is_package_private() ? acc_package_private : acc_private; } tty->print_cr("overriding with %s::%s index %d, original flags: %x overriders flags: %x", _klass->internal_name(), (target_method() != NULL) ? target_method()->name()->as_C_string() : "", i, at, targetacc); } #endif /*PRODUCT*/ } else { #ifndef PRODUCT if (PrintVtables && Verbose) { AccessType targetacc; if (target_method()->is_protected() || target_method()->is_public()) { targetacc = acc_publicprotected; } else { targetacc = target_method()->is_package_private() ? acc_package_private : acc_private; } tty->print_cr("override %s %s::%s at index %d, original flags: %x overriders flags: %x", allocate_new ? "+ new" : "only", _klass->internal_name(), (target_method() != NULL) ? target_method()->name()->as_C_string() : "", i, at, targetacc); } #endif /*PRODUCT*/ } } } } return allocate_new; } void klassVtable::put_method_at(methodOop m, int index) { assert(m->is_oop_or_null(), "Not an oop or null"); #ifndef PRODUCT if (PrintVtables && Verbose) { tty->print_cr("adding %s::%s at index %d", _klass->internal_name(), (m != NULL) ? m->name()->as_C_string() : "", index); } assert(unchecked_method_at(index)->is_oop_or_null(), "Not an oop or null"); #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, // when the Universe is boostrapping, a super's vtable might not be initialized. bool klassVtable::needs_new_vtable_entry(methodOop target_method, klassOop super, oop classloader, symbolOop classname, AccessFlags class_flags) { if ((class_flags.is_final() || target_method->is_final()) || // 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()) // is never called dynamically-bound ) { return false; } // we need a new entry if there is no superclass if (super == NULL) { return true; } // private methods always have a new entry in the vtable if (target_method->is_private()) { return true; } // search through the super class hierarchy to see if we need // a new entry symbolOop name = target_method->name(); symbolOop signature = target_method->signature(); klassOop k = super; methodOop match_method = NULL; instanceKlass *holder = NULL; while (k != NULL) { // lookup through the hierarchy for a method with matching name and sign. match_method = instanceKlass::cast(k)->lookup_method(name, signature); if (match_method == NULL) { break; // we still have to search for a matching miranda method } // get the class holding the matching method holder = instanceKlass::cast(match_method->method_holder()); if (!match_method->is_static()) { // we want only instance method matches if ((target_method->is_public() || target_method->is_protected()) && (match_method->is_public() || match_method->is_protected())) { // target and match are public/protected; we do not need a new entry return false; } if (target_method->is_package_private() && match_method->is_package_private() && holder->is_same_class_package(classloader, classname)) { // target and match are P private; we do not need a new entry return false; } } k = holder->super(); // haven't found a 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. if (target_method->is_public() || target_method->is_protected()) { instanceKlass *sk = instanceKlass::cast(super); if (sk->has_miranda_methods()) { if (sk->lookup_method_in_all_interfaces(name, signature) != 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(symbolOop name, symbolOop signature) { // search from the bottom, might be faster for (int i = (length() - 1); i >= 0; i--) { methodOop m = table()[i].method(); if (is_miranda_entry_at(i) && m->name() == name && m->signature() == signature) { return i; } } return methodOopDesc::invalid_vtable_index; } // check if an entry is miranda bool klassVtable::is_miranda_entry_at(int i) { methodOop m = method_at(i); klassOop method_holder = m->method_holder(); instanceKlass *mhk = instanceKlass::cast(method_holder); // miranda methods are interface methods in a class's vtable if (mhk->is_interface()) { assert(m->is_public() && m->is_abstract(), "should be public and abstract"); assert(ik()->implements_interface(method_holder) , "this class should implement the interface"); assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method"); return true; } return false; } // check if a method is a miranda method, given a class's methods table and it's super // the caller must make sure that the method belongs to an interface implemented by the class bool klassVtable::is_miranda(methodOop m, objArrayOop class_methods, klassOop super) { symbolOop name = m->name(); symbolOop signature = m->signature(); if (instanceKlass::find_method(class_methods, name, signature) == NULL) { // did not find it in the method table of the current class if (super == NULL) { // super doesn't exist return true; } else { if (instanceKlass::cast(super)->lookup_method(name, signature) == NULL) { // super class hierarchy does not implement it return true; } } } return false; } void klassVtable::add_new_mirandas_to_list(GrowableArray* list_of_current_mirandas, objArrayOop current_interface_methods, objArrayOop class_methods, klassOop 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++) { methodOop im = methodOop(current_interface_methods->obj_at(i)); bool is_duplicate = false; int num_of_current_mirandas = list_of_current_mirandas->length(); // check for duplicate mirandas in different interfaces we implement for (int j = 0; j < num_of_current_mirandas; j++) { methodOop miranda = list_of_current_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, 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()) == NULL) { list_of_current_mirandas->append(im); } } } } } void klassVtable::get_mirandas(GrowableArray* mirandas, klassOop super, objArrayOop class_methods, objArrayOop local_interfaces) { assert((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(klassOop(local_interfaces->obj_at(i))); add_new_mirandas_to_list(mirandas, ik->methods(), class_methods, super); // iterate thru each local's super interfaces objArrayOop 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(klassOop(super_ifs->obj_at(j))); add_new_mirandas_to_list(mirandas, sik->methods(), class_methods, super); } } } // get number of mirandas int klassVtable::get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces) { ResourceMark rm; GrowableArray* mirandas = new GrowableArray(20); get_mirandas(mirandas, super, class_methods, local_interfaces); return mirandas->length(); } // fill in mirandas void klassVtable::fill_in_mirandas(int& initialized) { ResourceMark rm; GrowableArray* mirandas = new GrowableArray(20); instanceKlass *this_ik = ik(); get_mirandas(mirandas, this_ik->super(), this_ik->methods(), this_ik->local_interfaces()); int num_mirandas = mirandas->length(); for (int i = 0; i < num_mirandas; i++) { put_method_at(mirandas->at(i), initialized); initialized++; } } void klassVtable::copy_vtable_to(vtableEntry* start) { Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size()); } void klassVtable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods, int methods_length, bool * trace_name_printed) { // search the vtable for uses of either obsolete or EMCP methods for (int j = 0; j < methods_length; j++) { methodOop old_method = old_methods[j]; methodOop new_method = new_methods[j]; // In the vast majority of cases we could get the vtable index // by using: old_method->vtable_index() // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX() // in sun.awt.X11.XFramePeer where methods occur more than once in the // vtable, so, alas, we must do an exhaustive search. for (int index = 0; index < length(); index++) { if (unchecked_method_at(index) == old_method) { put_method_at(new_method, index); 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", Klass::cast(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)", new_method->name()->as_C_string(), new_method->signature()->as_C_string())); } } } } } // Garbage collection void klassVtable::oop_follow_contents() { int len = length(); for (int i = 0; i < len; i++) { MarkSweep::mark_and_push(adr_method_at(i)); } } #ifndef SERIALGC void klassVtable::oop_follow_contents(ParCompactionManager* cm) { int len = length(); for (int i = 0; i < len; i++) { PSParallelCompact::mark_and_push(cm, adr_method_at(i)); } } #endif // SERIALGC void klassVtable::oop_adjust_pointers() { int len = length(); for (int i = 0; i < len; i++) { MarkSweep::adjust_pointer(adr_method_at(i)); } } #ifndef SERIALGC void klassVtable::oop_update_pointers(ParCompactionManager* cm) { const int n = length(); for (int i = 0; i < n; i++) { PSParallelCompact::adjust_pointer(adr_method_at(i)); } } void klassVtable::oop_update_pointers(ParCompactionManager* cm, HeapWord* beg_addr, HeapWord* end_addr) { const int n = length(); const int entry_size = vtableEntry::size(); int beg_idx = 0; HeapWord* const method_0 = (HeapWord*)adr_method_at(0); if (beg_addr > method_0) { // it's safe to use cast, as we have guarantees on vtable size to be sane beg_idx = int((pointer_delta(beg_addr, method_0) + entry_size - 1) / entry_size); } oop* const beg_oop = adr_method_at(beg_idx); oop* const end_oop = MIN2((oop*)end_addr, adr_method_at(n)); for (oop* cur_oop = beg_oop; cur_oop < end_oop; cur_oop += entry_size) { PSParallelCompact::adjust_pointer(cur_oop); } } #endif // SERIALGC // Iterators void klassVtable::oop_oop_iterate(OopClosure* blk) { int len = length(); for (int i = 0; i < len; i++) { blk->do_oop(adr_method_at(i)); } } void klassVtable::oop_oop_iterate_m(OopClosure* blk, MemRegion mr) { int len = length(); int i; for (i = 0; i < len; i++) { if ((HeapWord*)adr_method_at(i) >= mr.start()) break; } for (; i < len; i++) { oop* adr = adr_method_at(i); if ((HeapWord*)adr < mr.end()) blk->do_oop(adr); } } //----------------------------------------------------------------------------------------- // Itable code // Initialize a itableMethodEntry void itableMethodEntry::initialize(methodOop m) { if (m == NULL) return; _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->as_klassOop()) + offset_entry->offset()); intptr_t* end = klass->end_of_itable(); _table_offset = (intptr_t*)offset_entry - (intptr_t*)klass->as_klassOop(); _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; } } // This lenght of the itable was either zero, or it has not yet been initialized. _table_offset = 0; _size_offset_table = 0; _size_method_table = 0; } // Garbage Collection void klassItable::oop_follow_contents() { // offset table itableOffsetEntry* ioe = offset_entry(0); for(int i = 0; i < _size_offset_table; i++) { MarkSweep::mark_and_push((oop*)&ioe->_interface); ioe++; } // method table itableMethodEntry* ime = method_entry(0); for(int j = 0; j < _size_method_table; j++) { MarkSweep::mark_and_push((oop*)&ime->_method); ime++; } } #ifndef SERIALGC void klassItable::oop_follow_contents(ParCompactionManager* cm) { // offset table itableOffsetEntry* ioe = offset_entry(0); for(int i = 0; i < _size_offset_table; i++) { PSParallelCompact::mark_and_push(cm, (oop*)&ioe->_interface); ioe++; } // method table itableMethodEntry* ime = method_entry(0); for(int j = 0; j < _size_method_table; j++) { PSParallelCompact::mark_and_push(cm, (oop*)&ime->_method); ime++; } } #endif // SERIALGC void klassItable::oop_adjust_pointers() { // offset table itableOffsetEntry* ioe = offset_entry(0); for(int i = 0; i < _size_offset_table; i++) { MarkSweep::adjust_pointer((oop*)&ioe->_interface); ioe++; } // method table itableMethodEntry* ime = method_entry(0); for(int j = 0; j < _size_method_table; j++) { MarkSweep::adjust_pointer((oop*)&ime->_method); ime++; } } #ifndef SERIALGC void klassItable::oop_update_pointers(ParCompactionManager* cm) { // offset table itableOffsetEntry* ioe = offset_entry(0); for(int i = 0; i < _size_offset_table; i++) { PSParallelCompact::adjust_pointer((oop*)&ioe->_interface); ioe++; } // method table itableMethodEntry* ime = method_entry(0); for(int j = 0; j < _size_method_table; j++) { PSParallelCompact::adjust_pointer((oop*)&ime->_method); ime++; } } void klassItable::oop_update_pointers(ParCompactionManager* cm, HeapWord* beg_addr, HeapWord* end_addr) { // offset table itableOffsetEntry* ioe = offset_entry(0); for(int i = 0; i < _size_offset_table; i++) { oop* p = (oop*)&ioe->_interface; PSParallelCompact::adjust_pointer(p, beg_addr, end_addr); ioe++; } // method table itableMethodEntry* ime = method_entry(0); for(int j = 0; j < _size_method_table; j++) { oop* p = (oop*)&ime->_method; PSParallelCompact::adjust_pointer(p, beg_addr, end_addr); ime++; } } #endif // SERIALGC // Iterators void klassItable::oop_oop_iterate(OopClosure* blk) { // offset table itableOffsetEntry* ioe = offset_entry(0); for(int i = 0; i < _size_offset_table; i++) { blk->do_oop((oop*)&ioe->_interface); ioe++; } // method table itableMethodEntry* ime = method_entry(0); for(int j = 0; j < _size_method_table; j++) { blk->do_oop((oop*)&ime->_method); ime++; } } void klassItable::oop_oop_iterate_m(OopClosure* blk, MemRegion mr) { // offset table itableOffsetEntry* ioe = offset_entry(0); for(int i = 0; i < _size_offset_table; i++) { oop* adr = (oop*)&ioe->_interface; if (mr.contains(adr)) blk->do_oop(adr); ioe++; } // method table itableMethodEntry* ime = method_entry(0); for(int j = 0; j < _size_method_table; j++) { oop* adr = (oop*)&ime->_method; if (mr.contains(adr)) blk->do_oop(adr); ime++; } } static int initialize_count = 0; // Initialization void klassItable::initialize_itable(bool checkconstraints, TRAPS) { // Cannot be setup doing bootstrapping if (Universe::is_bootstrapping()) return; int num_interfaces = nof_interfaces(); if (num_interfaces > 0) { if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count, _klass->name()->as_C_string()); // In debug mode, we got an extra NULL/NULL entry debug_only(num_interfaces--); assert(num_interfaces > 0, "to few interfaces in offset itable"); // Interate through all interfaces int i; for(i = 0; i < num_interfaces; i++) { itableOffsetEntry* ioe = offset_entry(i); 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); } #ifdef ASSERT // Check that the last entry is empty itableOffsetEntry* ioe = offset_entry(i); assert(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing"); #endif } } void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) { objArrayHandle methods(THREAD, instanceKlass::cast(interf_h())->methods()); int nof_methods = methods()->length(); HandleMark hm; KlassHandle klass = _klass; 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_num = 0; // Skip first methodOop if it is a class initializer int i = ((methodOop)methods()->obj_at(0))->name() != vmSymbols::class_initializer_name() ? 0 : 1; // m, method_name, method_signature, klass reset each loop so they // don't need preserving across check_signature_loaders call // methods needs a handle in case of gc from check_signature_loaders for(; i < nof_methods; i++) { methodOop m = (methodOop)methods()->obj_at(i); symbolOop method_name = m->name(); symbolOop method_signature = m->signature(); // This is same code as in Linkresolver::lookup_instance_method_in_klasses methodOop target = klass->uncached_lookup_method(method_name, method_signature); while (target != NULL && target->is_static()) { // continue with recursive lookup through the superclass klassOop super = Klass::cast(target->method_holder())->super(); target = (super == NULL) ? methodOop(NULL) : Klass::cast(super)->uncached_lookup_method(method_name, method_signature); } if (target == NULL || !target->is_public() || target->is_abstract()) { // Entry do not resolve. Leave it empty } else { // Entry did resolve, check loader constraints before initializing // if checkconstraints requested methodHandle target_h (THREAD, target); // preserve across gc if (checkconstraints) { Handle method_holder_loader (THREAD, instanceKlass::cast(target->method_holder())->class_loader()); if (method_holder_loader() != interface_loader()) { ResourceMark rm(THREAD); char* failed_type_name = SystemDictionary::check_signature_loaders(method_signature, method_holder_loader, interface_loader, true, CHECK); if (failed_type_name != 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_h()->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(); 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 itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target_h()); } // Progress to next entry ime_num++; } } // Update entry for specic methodOop void klassItable::initialize_with_method(methodOop m) { itableMethodEntry* ime = method_entry(0); for(int i = 0; i < _size_method_table; i++) { if (ime->method() == m) { ime->initialize(m); } ime++; } } void klassItable::adjust_method_entries(methodOop* old_methods, methodOop* new_methods, int methods_length, bool * trace_name_printed) { // search the itable for uses of either obsolete or EMCP methods for (int j = 0; j < methods_length; j++) { methodOop old_method = old_methods[j]; methodOop new_method = new_methods[j]; itableMethodEntry* ime = method_entry(0); for (int i = 0; i < _size_method_table; i++) { if (ime->method() == old_method) { 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", Klass::cast(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())); } break; } ime++; } } } // Setup class InterfaceVisiterClosure : public StackObj { public: virtual void doit(klassOop intf, int method_count) = 0; }; // Visit all interfaces with at-least one method (excluding ) void visit_all_interfaces(objArrayOop transitive_intf, InterfaceVisiterClosure *blk) { // Handle array argument for(int i = 0; i < transitive_intf->length(); i++) { klassOop intf = (klassOop)transitive_intf->obj_at(i); assert(Klass::cast(intf)->is_interface(), "sanity check"); // Find no. of methods excluding a int method_count = instanceKlass::cast(intf)->methods()->length(); if (method_count > 0) { methodOop m = (methodOop)instanceKlass::cast(intf)->methods()->obj_at(0); assert(m != NULL && m->is_method(), "sanity check"); if (m->name() == vmSymbols::object_initializer_name()) { 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(klassOop 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(klassOop 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(objArrayHandle transitive_interfaces) { // Count no of interfaces and total number of interface methods CountInterfacesClosure cic; visit_all_interfaces(transitive_interfaces(), &cic); // Add one extra entry in debug mode, so we can null-terminate the table int nof_methods = cic.nof_methods(); int nof_interfaces = cic.nof_interfaces(); debug_only(if (nof_interfaces > 0) nof_interfaces++); int itable_size = calc_itable_size(nof_interfaces, 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 in debug mode, so we can null-terminate the table debug_only(if (nof_interfaces > 0) nof_interfaces++); assert(compute_itable_size(objArrayHandle(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) <= klass->start_of_static_fields(), "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->as_klassOop(), 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 } // m must be a method in an interface int klassItable::compute_itable_index(methodOop m) { klassOop intf = m->method_holder(); assert(instanceKlass::cast(intf)->is_interface(), "sanity check"); objArrayOop methods = instanceKlass::cast(intf)->methods(); int index = 0; while(methods->obj_at(index) != m) { index++; assert(index < methods->length(), "should find index for resolve_invoke"); } // Adjust for , which is left out of table if first method if (methods->length() > 0 && ((methodOop)methods->obj_at(0))->name() == vmSymbols::class_initializer_name()) { index--; } return index; } 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) { fatal1("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 klassOop 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 fatal1("vtableEntry %#lx: 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(klassOop k) { Klass* kl = k->klass_part(); 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); } bool klassVtable::check_no_old_entries() { // Check that there really is no entry for (int i = 0; i < length(); i++) { methodOop m = unchecked_method_at(i); if (m != NULL) { if (m->is_old()) { return false; } } } return true; } void klassVtable::dump_vtable() { tty->print_cr("vtable dump --"); for (int i = 0; i < length(); i++) { methodOop m = unchecked_method_at(i); if (m != NULL) { tty->print(" (%5d) ", i); m->access_flags().print_on(tty); tty->print(" -- "); m->print_name(tty); tty->cr(); } } } 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