diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/oops/klassVtable.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/hotspot/share/oops/klassVtable.cpp Tue Sep 12 19:03:39 2017 +0200 @@ -0,0 +1,1613 @@ +/* + * 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/shared/gcLocker.hpp" +#include "logging/log.hpp" +#include "logging/logStream.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/jvm.h" +#include "runtime/arguments.hpp" +#include "runtime/handles.inline.hpp" +#include "utilities/copy.hpp" + +inline InstanceKlass* klassVtable::ik() const { + return InstanceKlass::cast(_klass); +} + +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* all_mirandas, const Klass* super, + Array* methods, AccessFlags class_flags, u2 major_version, + Handle classloader, Symbol* classname, Array* local_interfaces, + TRAPS) { + NoSafepointVerifier nsv; + + // set up default result values + int vtable_length = 0; + + // start off with super's vtable length + vtable_length = super == NULL ? 0 : super->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, major_version, THREAD)) { + vtable_length += vtableEntry::size(); // we need a new entry + } + } + + GrowableArray 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 && vtable_length != Universe::base_vtable_size()) { + if (Universe::is_bootstrapping()) { + // Someone is attempting to override java.lang.Object incorrectly on the + // bootclasspath. The JVM cannot recover from this error including throwing + // an exception + vm_exit_during_initialization("Incompatible definition of java.lang.Object"); + } else { + // 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(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(Klass* super) { + if (super == 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 + klassVtable superVtable = super->vtable(); + assert(superVtable.length() <= _length, "vtable too short"); +#ifdef ASSERT + superVtable.verify(tty, true); +#endif + superVtable.copy_vtable_to(table()); + if (log_develop_is_enabled(Trace, vtables)) { + ResourceMark rm; + log_develop_trace(vtables)("copy vtable from %s to %s size %d", + super->internal_name(), klass()->internal_name(), + _length); + } + 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. + Klass* super = _klass->java_super(); + int nofNewEntries = 0; + + bool is_shared = _klass->is_shared(); + + if (!_klass->is_array_klass()) { + ResourceMark rm(THREAD); + log_develop_debug(vtables)("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->is_array_klass()) { + assert(super_vtable_len == _length, "arrays shouldn't introduce new methods"); + } else { + assert(_klass->is_instance_klass(), "must be InstanceKlass"); + + Array* 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* default_methods = ik()->default_methods(); + if (default_methods != NULL) { + len = default_methods->length(); + if (len > 0) { + Array* 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)); + assert(!mh->is_private(), "private interface method in the default method list"); + 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, for classfile versions for which we do not do transitive override + // calculations. + if (ik()->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION) { + assert(initialized == _length, "vtable initialization failed"); + } else { + assert(initialized <= _length, "vtable initialization failed"); + for(;initialized < _length; initialized++) { + table()[initialized].clear(); + } + } + 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, const 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)) { + if (log_develop_is_enabled(Trace, vtables)) { + ResourceMark rm(THREAD); + LogTarget(Trace, vtables) lt; + LogStream ls(lt); + char* sig = target_method()->name_and_sig_as_C_string(); + ls.print("transitive overriding superclass %s with %s index %d, original flags: ", + supersuperklass->internal_name(), + sig, vtable_index); + super_method->print_linkage_flags(&ls); + ls.print("overriders flags: "); + target_method->print_linkage_flags(&ls); + ls.cr(); + } + + 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 = superk->super() == NULL ? NULL : InstanceKlass::cast(superk->super()); + } + + return superk; +} + +static void log_vtables(int i, bool overrides, const methodHandle& target_method, + Klass* target_klass, Method* super_method, + Thread* thread) { +#ifndef PRODUCT + if (log_develop_is_enabled(Trace, vtables)) { + ResourceMark rm(thread); + LogTarget(Trace, vtables) lt; + LogStream ls(lt); + char* sig = target_method()->name_and_sig_as_C_string(); + if (overrides) { + ls.print("overriding with %s index %d, original flags: ", + sig, i); + } else { + ls.print("NOT overriding with %s index %d, original flags: ", + sig, i); + } + super_method->print_linkage_flags(&ls); + ls.print("overriders flags: "); + target_method->print_linkage_flags(&ls); + ls.cr(); + } +#endif +} + +// 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, const methodHandle& target_method, + int super_vtable_len, int default_index, + bool checkconstraints, TRAPS) { + ResourceMark rm; + bool allocate_new = true; + assert(klass->is_instance_klass(), "must be InstanceKlass"); + + Array* def_vtable_indices = NULL; + bool is_default = false; + + // default methods are non-private 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(!target_method()->is_private(), "private interface method flagged as default"); + 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 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. + // Private interface methods have no itable index and are always invoked nonvirtually, + // so they retain their nonvirtual_vtable_index value, and therefore can_be_statically_bound() + // will return true. + if ((!is_default || !target_method()->has_itable_index()) && !target_method()->is_private()) { + 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(); + + Klass* target_klass = 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(); + + // Whether the method is being overridden + bool overrides = false; + + // 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); + overrides = true; + 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"); + } + } else { + overrides = false; + } + log_vtables(i, overrides, target_method, target_klass, super_method, THREAD); + } + } + 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 { + if (log_develop_is_enabled(Trace, vtables)) { + ResourceMark rm; + LogTarget(Trace, vtables) lt; + LogStream ls(lt); + const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : ""; + ls.print("adding %s at index %d, flags: ", sig, index); + if (m != NULL) { + m->print_linkage_flags(&ls); + } + ls.cr(); + } + 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(const methodHandle& target_method, + const Klass* super, + Handle classloader, + Symbol* classname, + AccessFlags class_flags, + u2 major_version, + 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()) + // 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()) { + assert(target_method()->is_default_method() || target_method()->is_private(), + "unexpected interface method type"); + 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. + 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(); + const 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, for versions supporting transitive override + if (major_version >= VTABLE_TRANSITIVE_OVERRIDE_VERSION) { + k = superk->super(); // haven't found an override match yet; continue to look + } else { + break; + } + } + + // 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. + const 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* class_methods, + Array* default_methods, const 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; + } + + // Iterate on all superclasses, which should be 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 (const Klass* cursuper = super; cursuper != NULL; cursuper = cursuper->super()) + { + if (InstanceKlass::cast(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* new_mirandas, GrowableArray* all_mirandas, + Array* current_interface_methods, Array* class_methods, + Array* default_methods, const 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? + const 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* new_mirandas, + GrowableArray* all_mirandas, + const Klass* super, + Array* class_methods, + Array* default_methods, + Array* 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* 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 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 (log_develop_is_enabled(Trace, vtables)) { + Method* meth = mirandas.at(i); + ResourceMark rm(Thread::current()); + LogTarget(Trace, vtables) lt; + LogStream ls(lt); + if (meth != NULL) { + char* sig = meth->name_and_sig_as_C_string(); + ls.print("fill in mirandas with %s index %d, flags: ", + sig, initialized); + meth->print_linkage_flags(&ls); + ls.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* 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 (log_is_enabled(Info, redefine, class, update)) { + ResourceMark rm; + if (!(*trace_name_printed)) { + log_info(redefine, class, update) + ("adjust: klassname=%s for methods from name=%s", + _klass->external_name(), old_method->method_holder()->external_name()); + *trace_name_printed = true; + } + log_debug(redefine, class, update, vtables) + ("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; + +#ifdef ASSERT + 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"); + } +#endif + _method = m; +} + +klassItable::klassItable(InstanceKlass* 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) { + log_develop_debug(itables)("%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); + Klass* interf = ioe->interface_klass(); + assert(interf != NULL && ioe->offset() != 0, "bad offset entry in itable"); + initialize_itable_for_interface(ioe->offset(), interf, 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; // or + if (m->is_private()) return false; // requires invokeSpecial + // 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 + log_develop_debug(itables)("%3d: Initializing itable indices for interface %s", + ++initialize_count, klass->name()->as_C_string()); + Array* 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 (log_develop_is_enabled(Trace, itables)) { + ResourceMark rm; + LogTarget(Trace, itables) lt; + LogStream ls(lt); + assert(m != NULL, "methods can never be null"); + const char* sig = m->name_and_sig_as_C_string(); + if (m->has_vtable_index()) { + ls.print("vtable index %d for method: %s, flags: ", m->vtable_index(), sig); + } else { + ls.print("itable index %d for method: %s, flags: ", ime_num, sig); + } + m->print_linkage_flags(&ls); + ls.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->is_instance_klass(), "must be"); + assert(interf->is_interface(), "must be"); + Array* methods = InstanceKlass::cast(interf)->methods(); + int nof_methods = methods->length(); + int length = 0; + while (nof_methods > 0) { + Method* m = methods->at(nof_methods-1); + if (m->has_itable_index()) { + length = m->itable_index() + 1; + break; + } + nof_methods -= 1; + } +#ifdef ASSERT + int nof_methods_copy = nof_methods; + while (nof_methods_copy > 0) { + Method* mm = methods->at(--nof_methods_copy); + assert(!mm->has_itable_index() || mm->itable_index() < length, ""); + } +#endif //ASSERT + // return the rightmost itable index, plus one; or 0 if no methods have + // itable indices + return length; +} + + +void klassItable::initialize_itable_for_interface(int method_table_offset, Klass* interf, bool checkconstraints, TRAPS) { + Array* methods = InstanceKlass::cast(interf)->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)->class_loader()); + + int ime_count = method_count_for_interface(interf); + 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 + target = LinkResolver::lookup_instance_method_in_klasses(_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)->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 (log_develop_is_enabled(Trace, itables)) { + ResourceMark rm(THREAD); + if (target() != NULL) { + LogTarget(Trace, itables) lt; + LogStream ls(lt); + char* sig = target()->name_and_sig_as_C_string(); + ls.print("interface: %s, ime_num: %d, target: %s, method_holder: %s ", + interf->internal_name(), ime_num, sig, + target()->method_holder()->internal_name()); + ls.print("target_method flags: "); + target()->print_linkage_flags(&ls); + ls.cr(); + } + } + } + } +} + +#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 (log_is_enabled(Info, redefine, class, update)) { + ResourceMark rm; + if (!(*trace_name_printed)) { + log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name()); + *trace_name_printed = true; + } + log_trace(redefine, class, update, itables) + ("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* 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* 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* 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 * wordSize); + + return itable_size; +} + + +// Fill out offset table and interface klasses into the itable space +void klassItable::setup_itable_offset_table(InstanceKlass* 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* 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("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)); + Klass* vtklass = vt->klass(); + if (vtklass->is_instance_klass() && + (InstanceKlass::cast(vtklass)->major_version() >= klassVtable::VTABLE_TRANSITIVE_OVERRIDE_VERSION)) { + assert(method() != NULL, "must have set method"); + } + if (method() != NULL) { + method()->verify(); + // we sub_type, because it could be a miranda method + if (!vtklass->is_subtype_of(method()->method_holder())) { +#ifndef PRODUCT + print(); +#endif + fatal("vtableEntry " PTR_FORMAT ": method is from subclass", p2i(this)); + } + } +} + +#ifndef PRODUCT + +void vtableEntry::print() { + ResourceMark rm; + tty->print("vtableEntry %s: ", method()->name()->as_C_string()); + if (Verbose) { + tty->print("m " PTR_FORMAT " ", p2i(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(); + no_klasses++; + if (kl->is_instance_klass()) { + no_instance_klasses++; + kl->array_klasses_do(do_class); + } + if (kl->is_array_klass()) { + no_array_klasses++; + sum_of_array_vtable_len += vt.length(); + } + sum_of_vtable_len += vt.length(); + } + + static void compute() { + ClassLoaderDataGraph::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("%6lu K uses for itables (average by class: %ld bytes)", _total_size / K, _total_size / _total_classes); +} + +#endif // PRODUCT