--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/classfile/defaultMethods.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,1094 @@
+/*
+ * Copyright (c) 2012, 2016, 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/bytecodeAssembler.hpp"
+#include "classfile/defaultMethods.hpp"
+#include "classfile/symbolTable.hpp"
+#include "logging/log.hpp"
+#include "logging/logStream.hpp"
+#include "memory/allocation.hpp"
+#include "memory/metadataFactory.hpp"
+#include "memory/resourceArea.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/signature.hpp"
+#include "runtime/thread.hpp"
+#include "oops/instanceKlass.hpp"
+#include "oops/klass.hpp"
+#include "oops/method.hpp"
+#include "utilities/accessFlags.hpp"
+#include "utilities/exceptions.hpp"
+#include "utilities/ostream.hpp"
+#include "utilities/pair.hpp"
+#include "utilities/resourceHash.hpp"
+
+typedef enum { QUALIFIED, DISQUALIFIED } QualifiedState;
+
+// Because we use an iterative algorithm when iterating over the type
+// hierarchy, we can't use traditional scoped objects which automatically do
+// cleanup in the destructor when the scope is exited. PseudoScope (and
+// PseudoScopeMark) provides a similar functionality, but for when you want a
+// scoped object in non-stack memory (such as in resource memory, as we do
+// here). You've just got to remember to call 'destroy()' on the scope when
+// leaving it (and marks have to be explicitly added).
+class PseudoScopeMark : public ResourceObj {
+ public:
+ virtual void destroy() = 0;
+};
+
+class PseudoScope : public ResourceObj {
+ private:
+ GrowableArray<PseudoScopeMark*> _marks;
+ public:
+
+ static PseudoScope* cast(void* data) {
+ return static_cast<PseudoScope*>(data);
+ }
+
+ void add_mark(PseudoScopeMark* psm) {
+ _marks.append(psm);
+ }
+
+ void destroy() {
+ for (int i = 0; i < _marks.length(); ++i) {
+ _marks.at(i)->destroy();
+ }
+ }
+};
+
+static void print_slot(outputStream* str, Symbol* name, Symbol* signature) {
+ str->print("%s%s", name->as_C_string(), signature->as_C_string());
+}
+
+static void print_method(outputStream* str, Method* mo, bool with_class=true) {
+ if (with_class) {
+ str->print("%s.", mo->klass_name()->as_C_string());
+ }
+ print_slot(str, mo->name(), mo->signature());
+}
+
+/**
+ * Perform a depth-first iteration over the class hierarchy, applying
+ * algorithmic logic as it goes.
+ *
+ * This class is one half of the inheritance hierarchy analysis mechanism.
+ * It is meant to be used in conjunction with another class, the algorithm,
+ * which is indicated by the ALGO template parameter. This class can be
+ * paired with any algorithm class that provides the required methods.
+ *
+ * This class contains all the mechanics for iterating over the class hierarchy
+ * starting at a particular root, without recursing (thus limiting stack growth
+ * from this point). It visits each superclass (if present) and superinterface
+ * in a depth-first manner, with callbacks to the ALGO class as each class is
+ * encountered (visit()), The algorithm can cut-off further exploration of a
+ * particular branch by returning 'false' from a visit() call.
+ *
+ * The ALGO class, must provide a visit() method, which each of which will be
+ * called once for each node in the inheritance tree during the iteration. In
+ * addition, it can provide a memory block via new_node_data(InstanceKlass*),
+ * which it can use for node-specific storage (and access via the
+ * current_data() and data_at_depth(int) methods).
+ *
+ * Bare minimum needed to be an ALGO class:
+ * class Algo : public HierarchyVisitor<Algo> {
+ * void* new_node_data(InstanceKlass* cls) { return NULL; }
+ * void free_node_data(void* data) { return; }
+ * bool visit() { return true; }
+ * };
+ */
+template <class ALGO>
+class HierarchyVisitor : StackObj {
+ private:
+
+ class Node : public ResourceObj {
+ public:
+ InstanceKlass* _class;
+ bool _super_was_visited;
+ int _interface_index;
+ void* _algorithm_data;
+
+ Node(InstanceKlass* cls, void* data, bool visit_super)
+ : _class(cls), _super_was_visited(!visit_super),
+ _interface_index(0), _algorithm_data(data) {}
+
+ int number_of_interfaces() { return _class->local_interfaces()->length(); }
+ int interface_index() { return _interface_index; }
+ void set_super_visited() { _super_was_visited = true; }
+ void increment_visited_interface() { ++_interface_index; }
+ void set_all_interfaces_visited() {
+ _interface_index = number_of_interfaces();
+ }
+ bool has_visited_super() { return _super_was_visited; }
+ bool has_visited_all_interfaces() {
+ return interface_index() >= number_of_interfaces();
+ }
+ InstanceKlass* interface_at(int index) {
+ return InstanceKlass::cast(_class->local_interfaces()->at(index));
+ }
+ InstanceKlass* next_super() { return _class->java_super(); }
+ InstanceKlass* next_interface() {
+ return interface_at(interface_index());
+ }
+ };
+
+ bool _cancelled;
+ GrowableArray<Node*> _path;
+
+ Node* current_top() const { return _path.top(); }
+ bool has_more_nodes() const { return !_path.is_empty(); }
+ void push(InstanceKlass* cls, void* data) {
+ assert(cls != NULL, "Requires a valid instance class");
+ Node* node = new Node(cls, data, has_super(cls));
+ _path.push(node);
+ }
+ void pop() { _path.pop(); }
+
+ void reset_iteration() {
+ _cancelled = false;
+ _path.clear();
+ }
+ bool is_cancelled() const { return _cancelled; }
+
+ // This code used to skip interface classes because their only
+ // superclass was j.l.Object which would be also covered by class
+ // superclass hierarchy walks. Now that the starting point can be
+ // an interface, we must ensure we catch j.l.Object as the super.
+ static bool has_super(InstanceKlass* cls) {
+ return cls->super() != NULL;
+ }
+
+ Node* node_at_depth(int i) const {
+ return (i >= _path.length()) ? NULL : _path.at(_path.length() - i - 1);
+ }
+
+ protected:
+
+ // Accessors available to the algorithm
+ int current_depth() const { return _path.length() - 1; }
+
+ InstanceKlass* class_at_depth(int i) {
+ Node* n = node_at_depth(i);
+ return n == NULL ? NULL : n->_class;
+ }
+ InstanceKlass* current_class() { return class_at_depth(0); }
+
+ void* data_at_depth(int i) {
+ Node* n = node_at_depth(i);
+ return n == NULL ? NULL : n->_algorithm_data;
+ }
+ void* current_data() { return data_at_depth(0); }
+
+ void cancel_iteration() { _cancelled = true; }
+
+ public:
+
+ void run(InstanceKlass* root) {
+ ALGO* algo = static_cast<ALGO*>(this);
+
+ reset_iteration();
+
+ void* algo_data = algo->new_node_data(root);
+ push(root, algo_data);
+ bool top_needs_visit = true;
+
+ do {
+ Node* top = current_top();
+ if (top_needs_visit) {
+ if (algo->visit() == false) {
+ // algorithm does not want to continue along this path. Arrange
+ // it so that this state is immediately popped off the stack
+ top->set_super_visited();
+ top->set_all_interfaces_visited();
+ }
+ top_needs_visit = false;
+ }
+
+ if (top->has_visited_super() && top->has_visited_all_interfaces()) {
+ algo->free_node_data(top->_algorithm_data);
+ pop();
+ } else {
+ InstanceKlass* next = NULL;
+ if (top->has_visited_super() == false) {
+ next = top->next_super();
+ top->set_super_visited();
+ } else {
+ next = top->next_interface();
+ top->increment_visited_interface();
+ }
+ assert(next != NULL, "Otherwise we shouldn't be here");
+ algo_data = algo->new_node_data(next);
+ push(next, algo_data);
+ top_needs_visit = true;
+ }
+ } while (!is_cancelled() && has_more_nodes());
+ }
+};
+
+class PrintHierarchy : public HierarchyVisitor<PrintHierarchy> {
+ private:
+ outputStream* _st;
+ public:
+ bool visit() {
+ InstanceKlass* cls = current_class();
+ streamIndentor si(_st, current_depth() * 2);
+ _st->indent().print_cr("%s", cls->name()->as_C_string());
+ return true;
+ }
+
+ void* new_node_data(InstanceKlass* cls) { return NULL; }
+ void free_node_data(void* data) { return; }
+
+ PrintHierarchy(outputStream* st = tty) : _st(st) {}
+};
+
+// Used to register InstanceKlass objects and all related metadata structures
+// (Methods, ConstantPools) as "in-use" by the current thread so that they can't
+// be deallocated by class redefinition while we're using them. The classes are
+// de-registered when this goes out of scope.
+//
+// Once a class is registered, we need not bother with methodHandles or
+// constantPoolHandles for it's associated metadata.
+class KeepAliveRegistrar : public StackObj {
+ private:
+ Thread* _thread;
+ GrowableArray<ConstantPool*> _keep_alive;
+
+ public:
+ KeepAliveRegistrar(Thread* thread) : _thread(thread), _keep_alive(20) {
+ assert(thread == Thread::current(), "Must be current thread");
+ }
+
+ ~KeepAliveRegistrar() {
+ for (int i = _keep_alive.length() - 1; i >= 0; --i) {
+ ConstantPool* cp = _keep_alive.at(i);
+ int idx = _thread->metadata_handles()->find_from_end(cp);
+ assert(idx > 0, "Must be in the list");
+ _thread->metadata_handles()->remove_at(idx);
+ }
+ }
+
+ // Register a class as 'in-use' by the thread. It's fine to register a class
+ // multiple times (though perhaps inefficient)
+ void register_class(InstanceKlass* ik) {
+ ConstantPool* cp = ik->constants();
+ _keep_alive.push(cp);
+ _thread->metadata_handles()->push(cp);
+ }
+};
+
+class KeepAliveVisitor : public HierarchyVisitor<KeepAliveVisitor> {
+ private:
+ KeepAliveRegistrar* _registrar;
+
+ public:
+ KeepAliveVisitor(KeepAliveRegistrar* registrar) : _registrar(registrar) {}
+
+ void* new_node_data(InstanceKlass* cls) { return NULL; }
+ void free_node_data(void* data) { return; }
+
+ bool visit() {
+ _registrar->register_class(current_class());
+ return true;
+ }
+};
+
+
+// A method family contains a set of all methods that implement a single
+// erased method. As members of the set are collected while walking over the
+// hierarchy, they are tagged with a qualification state. The qualification
+// state for an erased method is set to disqualified if there exists a path
+// from the root of hierarchy to the method that contains an interleaving
+// erased method defined in an interface.
+
+class MethodFamily : public ResourceObj {
+ private:
+
+ GrowableArray<Pair<Method*,QualifiedState> > _members;
+ ResourceHashtable<Method*, int> _member_index;
+
+ Method* _selected_target; // Filled in later, if a unique target exists
+ Symbol* _exception_message; // If no unique target is found
+ Symbol* _exception_name; // If no unique target is found
+
+ bool contains_method(Method* method) {
+ int* lookup = _member_index.get(method);
+ return lookup != NULL;
+ }
+
+ void add_method(Method* method, QualifiedState state) {
+ Pair<Method*,QualifiedState> entry(method, state);
+ _member_index.put(method, _members.length());
+ _members.append(entry);
+ }
+
+ void disqualify_method(Method* method) {
+ int* index = _member_index.get(method);
+ guarantee(index != NULL && *index >= 0 && *index < _members.length(), "bad index");
+ _members.at(*index).second = DISQUALIFIED;
+ }
+
+ Symbol* generate_no_defaults_message(TRAPS) const;
+ Symbol* generate_method_message(Symbol *klass_name, Method* method, TRAPS) const;
+ Symbol* generate_conflicts_message(GrowableArray<Method*>* methods, TRAPS) const;
+
+ public:
+
+ MethodFamily()
+ : _selected_target(NULL), _exception_message(NULL), _exception_name(NULL) {}
+
+ void set_target_if_empty(Method* m) {
+ if (_selected_target == NULL && !m->is_overpass()) {
+ _selected_target = m;
+ }
+ }
+
+ void record_qualified_method(Method* m) {
+ // If the method already exists in the set as qualified, this operation is
+ // redundant. If it already exists as disqualified, then we leave it as
+ // disqualfied. Thus we only add to the set if it's not already in the
+ // set.
+ if (!contains_method(m)) {
+ add_method(m, QUALIFIED);
+ }
+ }
+
+ void record_disqualified_method(Method* m) {
+ // If not in the set, add it as disqualified. If it's already in the set,
+ // then set the state to disqualified no matter what the previous state was.
+ if (!contains_method(m)) {
+ add_method(m, DISQUALIFIED);
+ } else {
+ disqualify_method(m);
+ }
+ }
+
+ bool has_target() const { return _selected_target != NULL; }
+ bool throws_exception() { return _exception_message != NULL; }
+
+ Method* get_selected_target() { return _selected_target; }
+ Symbol* get_exception_message() { return _exception_message; }
+ Symbol* get_exception_name() { return _exception_name; }
+
+ // Either sets the target or the exception error message
+ void determine_target(InstanceKlass* root, TRAPS) {
+ if (has_target() || throws_exception()) {
+ return;
+ }
+
+ // Qualified methods are maximally-specific methods
+ // These include public, instance concrete (=default) and abstract methods
+ GrowableArray<Method*> qualified_methods;
+ int num_defaults = 0;
+ int default_index = -1;
+ int qualified_index = -1;
+ for (int i = 0; i < _members.length(); ++i) {
+ Pair<Method*,QualifiedState> entry = _members.at(i);
+ if (entry.second == QUALIFIED) {
+ qualified_methods.append(entry.first);
+ qualified_index++;
+ if (entry.first->is_default_method()) {
+ num_defaults++;
+ default_index = qualified_index;
+
+ }
+ }
+ }
+
+ if (num_defaults == 0) {
+ // If the root klass has a static method with matching name and signature
+ // then do not generate an overpass method because it will hide the
+ // static method during resolution.
+ if (qualified_methods.length() == 0) {
+ _exception_message = generate_no_defaults_message(CHECK);
+ } else {
+ assert(root != NULL, "Null root class");
+ _exception_message = generate_method_message(root->name(), qualified_methods.at(0), CHECK);
+ }
+ _exception_name = vmSymbols::java_lang_AbstractMethodError();
+
+ // If only one qualified method is default, select that
+ } else if (num_defaults == 1) {
+ _selected_target = qualified_methods.at(default_index);
+
+ } else if (num_defaults > 1) {
+ _exception_message = generate_conflicts_message(&qualified_methods,CHECK);
+ _exception_name = vmSymbols::java_lang_IncompatibleClassChangeError();
+ LogTarget(Debug, defaultmethods) lt;
+ if (lt.is_enabled()) {
+ LogStream ls(lt);
+ _exception_message->print_value_on(&ls);
+ ls.cr();
+ }
+ }
+ }
+
+ bool contains_signature(Symbol* query) {
+ for (int i = 0; i < _members.length(); ++i) {
+ if (query == _members.at(i).first->signature()) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ void print_selected(outputStream* str, int indent) const {
+ assert(has_target(), "Should be called otherwise");
+ streamIndentor si(str, indent * 2);
+ str->indent().print("Selected method: ");
+ print_method(str, _selected_target);
+ Klass* method_holder = _selected_target->method_holder();
+ if (!method_holder->is_interface()) {
+ str->print(" : in superclass");
+ }
+ str->cr();
+ }
+
+ void print_exception(outputStream* str, int indent) {
+ assert(throws_exception(), "Should be called otherwise");
+ assert(_exception_name != NULL, "exception_name should be set");
+ streamIndentor si(str, indent * 2);
+ str->indent().print_cr("%s: %s", _exception_name->as_C_string(), _exception_message->as_C_string());
+ }
+};
+
+Symbol* MethodFamily::generate_no_defaults_message(TRAPS) const {
+ return SymbolTable::new_symbol("No qualifying defaults found", THREAD);
+}
+
+Symbol* MethodFamily::generate_method_message(Symbol *klass_name, Method* method, TRAPS) const {
+ stringStream ss;
+ ss.print("Method ");
+ Symbol* name = method->name();
+ Symbol* signature = method->signature();
+ ss.write((const char*)klass_name->bytes(), klass_name->utf8_length());
+ ss.print(".");
+ ss.write((const char*)name->bytes(), name->utf8_length());
+ ss.write((const char*)signature->bytes(), signature->utf8_length());
+ ss.print(" is abstract");
+ return SymbolTable::new_symbol(ss.base(), (int)ss.size(), THREAD);
+}
+
+Symbol* MethodFamily::generate_conflicts_message(GrowableArray<Method*>* methods, TRAPS) const {
+ stringStream ss;
+ ss.print("Conflicting default methods:");
+ for (int i = 0; i < methods->length(); ++i) {
+ Method* method = methods->at(i);
+ Symbol* klass = method->klass_name();
+ Symbol* name = method->name();
+ ss.print(" ");
+ ss.write((const char*)klass->bytes(), klass->utf8_length());
+ ss.print(".");
+ ss.write((const char*)name->bytes(), name->utf8_length());
+ }
+ return SymbolTable::new_symbol(ss.base(), (int)ss.size(), THREAD);
+}
+
+
+class StateRestorer;
+
+// StatefulMethodFamily is a wrapper around a MethodFamily that maintains the
+// qualification state during hierarchy visitation, and applies that state
+// when adding members to the MethodFamily
+class StatefulMethodFamily : public ResourceObj {
+ friend class StateRestorer;
+ private:
+ QualifiedState _qualification_state;
+
+ void set_qualification_state(QualifiedState state) {
+ _qualification_state = state;
+ }
+
+ protected:
+ MethodFamily* _method_family;
+
+ public:
+ StatefulMethodFamily() {
+ _method_family = new MethodFamily();
+ _qualification_state = QUALIFIED;
+ }
+
+ StatefulMethodFamily(MethodFamily* mf) {
+ _method_family = mf;
+ _qualification_state = QUALIFIED;
+ }
+
+ void set_target_if_empty(Method* m) { _method_family->set_target_if_empty(m); }
+
+ MethodFamily* get_method_family() { return _method_family; }
+
+ StateRestorer* record_method_and_dq_further(Method* mo);
+};
+
+class StateRestorer : public PseudoScopeMark {
+ private:
+ StatefulMethodFamily* _method;
+ QualifiedState _state_to_restore;
+ public:
+ StateRestorer(StatefulMethodFamily* dm, QualifiedState state)
+ : _method(dm), _state_to_restore(state) {}
+ ~StateRestorer() { destroy(); }
+ void restore_state() { _method->set_qualification_state(_state_to_restore); }
+ virtual void destroy() { restore_state(); }
+};
+
+StateRestorer* StatefulMethodFamily::record_method_and_dq_further(Method* mo) {
+ StateRestorer* mark = new StateRestorer(this, _qualification_state);
+ if (_qualification_state == QUALIFIED) {
+ _method_family->record_qualified_method(mo);
+ } else {
+ _method_family->record_disqualified_method(mo);
+ }
+ // Everything found "above"??? this method in the hierarchy walk is set to
+ // disqualified
+ set_qualification_state(DISQUALIFIED);
+ return mark;
+}
+
+// Represents a location corresponding to a vtable slot for methods that
+// neither the class nor any of it's ancestors provide an implementaion.
+// Default methods may be present to fill this slot.
+class EmptyVtableSlot : public ResourceObj {
+ private:
+ Symbol* _name;
+ Symbol* _signature;
+ int _size_of_parameters;
+ MethodFamily* _binding;
+
+ public:
+ EmptyVtableSlot(Method* method)
+ : _name(method->name()), _signature(method->signature()),
+ _size_of_parameters(method->size_of_parameters()), _binding(NULL) {}
+
+ Symbol* name() const { return _name; }
+ Symbol* signature() const { return _signature; }
+ int size_of_parameters() const { return _size_of_parameters; }
+
+ void bind_family(MethodFamily* lm) { _binding = lm; }
+ bool is_bound() { return _binding != NULL; }
+ MethodFamily* get_binding() { return _binding; }
+
+ void print_on(outputStream* str) const {
+ print_slot(str, name(), signature());
+ }
+};
+
+static bool already_in_vtable_slots(GrowableArray<EmptyVtableSlot*>* slots, Method* m) {
+ bool found = false;
+ for (int j = 0; j < slots->length(); ++j) {
+ if (slots->at(j)->name() == m->name() &&
+ slots->at(j)->signature() == m->signature() ) {
+ found = true;
+ break;
+ }
+ }
+ return found;
+}
+
+static GrowableArray<EmptyVtableSlot*>* find_empty_vtable_slots(
+ InstanceKlass* klass, const GrowableArray<Method*>* mirandas, TRAPS) {
+
+ assert(klass != NULL, "Must be valid class");
+
+ GrowableArray<EmptyVtableSlot*>* slots = new GrowableArray<EmptyVtableSlot*>();
+
+ // All miranda methods are obvious candidates
+ for (int i = 0; i < mirandas->length(); ++i) {
+ Method* m = mirandas->at(i);
+ if (!already_in_vtable_slots(slots, m)) {
+ slots->append(new EmptyVtableSlot(m));
+ }
+ }
+
+ // Also any overpasses in our superclasses, that we haven't implemented.
+ // (can't use the vtable because it is not guaranteed to be initialized yet)
+ InstanceKlass* super = klass->java_super();
+ while (super != NULL) {
+ for (int i = 0; i < super->methods()->length(); ++i) {
+ Method* m = super->methods()->at(i);
+ if (m->is_overpass() || m->is_static()) {
+ // m is a method that would have been a miranda if not for the
+ // default method processing that occurred on behalf of our superclass,
+ // so it's a method we want to re-examine in this new context. That is,
+ // unless we have a real implementation of it in the current class.
+ Method* impl = klass->lookup_method(m->name(), m->signature());
+ if (impl == NULL || impl->is_overpass() || impl->is_static()) {
+ if (!already_in_vtable_slots(slots, m)) {
+ slots->append(new EmptyVtableSlot(m));
+ }
+ }
+ }
+ }
+
+ // also any default methods in our superclasses
+ if (super->default_methods() != NULL) {
+ for (int i = 0; i < super->default_methods()->length(); ++i) {
+ Method* m = super->default_methods()->at(i);
+ // m is a method that would have been a miranda if not for the
+ // default method processing that occurred on behalf of our superclass,
+ // so it's a method we want to re-examine in this new context. That is,
+ // unless we have a real implementation of it in the current class.
+ Method* impl = klass->lookup_method(m->name(), m->signature());
+ if (impl == NULL || impl->is_overpass() || impl->is_static()) {
+ if (!already_in_vtable_slots(slots, m)) {
+ slots->append(new EmptyVtableSlot(m));
+ }
+ }
+ }
+ }
+ super = super->java_super();
+ }
+
+ LogTarget(Debug, defaultmethods) lt;
+ if (lt.is_enabled()) {
+ lt.print("Slots that need filling:");
+ ResourceMark rm;
+ LogStream ls(lt);
+ streamIndentor si(&ls);
+ for (int i = 0; i < slots->length(); ++i) {
+ ls.indent();
+ slots->at(i)->print_on(&ls);
+ ls.cr();
+ }
+ }
+
+ return slots;
+}
+
+// Iterates over the superinterface type hierarchy looking for all methods
+// with a specific erased signature.
+class FindMethodsByErasedSig : public HierarchyVisitor<FindMethodsByErasedSig> {
+ private:
+ // Context data
+ Symbol* _method_name;
+ Symbol* _method_signature;
+ StatefulMethodFamily* _family;
+
+ public:
+ FindMethodsByErasedSig(Symbol* name, Symbol* signature) :
+ _method_name(name), _method_signature(signature),
+ _family(NULL) {}
+
+ void get_discovered_family(MethodFamily** family) {
+ if (_family != NULL) {
+ *family = _family->get_method_family();
+ } else {
+ *family = NULL;
+ }
+ }
+
+ void* new_node_data(InstanceKlass* cls) { return new PseudoScope(); }
+ void free_node_data(void* node_data) {
+ PseudoScope::cast(node_data)->destroy();
+ }
+
+ // Find all methods on this hierarchy that match this
+ // method's erased (name, signature)
+ bool visit() {
+ PseudoScope* scope = PseudoScope::cast(current_data());
+ InstanceKlass* iklass = current_class();
+
+ Method* m = iklass->find_method(_method_name, _method_signature);
+ // private interface methods are not candidates for default methods
+ // invokespecial to private interface methods doesn't use default method logic
+ // private class methods are not candidates for default methods,
+ // private methods do not override default methods, so need to perform
+ // default method inheritance without including private methods
+ // The overpasses are your supertypes' errors, we do not include them
+ // future: take access controls into account for superclass methods
+ if (m != NULL && !m->is_static() && !m->is_overpass() && !m->is_private()) {
+ if (_family == NULL) {
+ _family = new StatefulMethodFamily();
+ }
+
+ if (iklass->is_interface()) {
+ StateRestorer* restorer = _family->record_method_and_dq_further(m);
+ scope->add_mark(restorer);
+ } else {
+ // This is the rule that methods in classes "win" (bad word) over
+ // methods in interfaces. This works because of single inheritance
+ // private methods in classes do not "win", they will be found
+ // first on searching, but overriding for invokevirtual needs
+ // to find default method candidates for the same signature
+ _family->set_target_if_empty(m);
+ }
+ }
+ return true;
+ }
+
+};
+
+
+
+static void create_defaults_and_exceptions(
+ GrowableArray<EmptyVtableSlot*>* slots, InstanceKlass* klass, TRAPS);
+
+static void generate_erased_defaults(
+ InstanceKlass* klass, GrowableArray<EmptyVtableSlot*>* empty_slots,
+ EmptyVtableSlot* slot, TRAPS) {
+
+ // sets up a set of methods with the same exact erased signature
+ FindMethodsByErasedSig visitor(slot->name(), slot->signature());
+ visitor.run(klass);
+
+ MethodFamily* family;
+ visitor.get_discovered_family(&family);
+ if (family != NULL) {
+ family->determine_target(klass, CHECK);
+ slot->bind_family(family);
+ }
+}
+
+static void merge_in_new_methods(InstanceKlass* klass,
+ GrowableArray<Method*>* new_methods, TRAPS);
+static void create_default_methods( InstanceKlass* klass,
+ GrowableArray<Method*>* new_methods, TRAPS);
+
+// This is the guts of the default methods implementation. This is called just
+// after the classfile has been parsed if some ancestor has default methods.
+//
+// First if finds any name/signature slots that need any implementation (either
+// because they are miranda or a superclass's implementation is an overpass
+// itself). For each slot, iterate over the hierarchy, to see if they contain a
+// signature that matches the slot we are looking at.
+//
+// For each slot filled, we generate an overpass method that either calls the
+// unique default method candidate using invokespecial, or throws an exception
+// (in the case of no default method candidates, or more than one valid
+// candidate). These methods are then added to the class's method list.
+// The JVM does not create bridges nor handle generic signatures here.
+void DefaultMethods::generate_default_methods(
+ InstanceKlass* klass, const GrowableArray<Method*>* mirandas, TRAPS) {
+ assert(klass != NULL, "invariant");
+
+ // This resource mark is the bound for all memory allocation that takes
+ // place during default method processing. After this goes out of scope,
+ // all (Resource) objects' memory will be reclaimed. Be careful if adding an
+ // embedded resource mark under here as that memory can't be used outside
+ // whatever scope it's in.
+ ResourceMark rm(THREAD);
+
+ // Keep entire hierarchy alive for the duration of the computation
+ constantPoolHandle cp(THREAD, klass->constants());
+ KeepAliveRegistrar keepAlive(THREAD);
+ KeepAliveVisitor loadKeepAlive(&keepAlive);
+ loadKeepAlive.run(klass);
+
+ LogTarget(Debug, defaultmethods) lt;
+ if (lt.is_enabled()) {
+ ResourceMark rm;
+ lt.print("%s %s requires default method processing",
+ klass->is_interface() ? "Interface" : "Class",
+ klass->name()->as_klass_external_name());
+ LogStream ls(lt);
+ PrintHierarchy printer(&ls);
+ printer.run(klass);
+ }
+
+ GrowableArray<EmptyVtableSlot*>* empty_slots =
+ find_empty_vtable_slots(klass, mirandas, CHECK);
+
+ for (int i = 0; i < empty_slots->length(); ++i) {
+ EmptyVtableSlot* slot = empty_slots->at(i);
+ LogTarget(Debug, defaultmethods) lt;
+ if (lt.is_enabled()) {
+ LogStream ls(lt);
+ streamIndentor si(&ls, 2);
+ ls.indent().print("Looking for default methods for slot ");
+ slot->print_on(&ls);
+ ls.cr();
+ }
+ generate_erased_defaults(klass, empty_slots, slot, CHECK);
+ }
+ log_debug(defaultmethods)("Creating defaults and overpasses...");
+ create_defaults_and_exceptions(empty_slots, klass, CHECK);
+ log_debug(defaultmethods)("Default method processing complete");
+}
+
+static int assemble_method_error(
+ BytecodeConstantPool* cp, BytecodeBuffer* buffer, Symbol* errorName, Symbol* message, TRAPS) {
+
+ Symbol* init = vmSymbols::object_initializer_name();
+ Symbol* sig = vmSymbols::string_void_signature();
+
+ BytecodeAssembler assem(buffer, cp);
+
+ assem._new(errorName);
+ assem.dup();
+ assem.load_string(message);
+ assem.invokespecial(errorName, init, sig);
+ assem.athrow();
+
+ return 3; // max stack size: [ exception, exception, string ]
+}
+
+static Method* new_method(
+ BytecodeConstantPool* cp, BytecodeBuffer* bytecodes, Symbol* name,
+ Symbol* sig, AccessFlags flags, int max_stack, int params,
+ ConstMethod::MethodType mt, TRAPS) {
+
+ address code_start = 0;
+ int code_length = 0;
+ InlineTableSizes sizes;
+
+ if (bytecodes != NULL && bytecodes->length() > 0) {
+ code_start = static_cast<address>(bytecodes->adr_at(0));
+ code_length = bytecodes->length();
+ }
+
+ Method* m = Method::allocate(cp->pool_holder()->class_loader_data(),
+ code_length, flags, &sizes,
+ mt, CHECK_NULL);
+
+ m->set_constants(NULL); // This will get filled in later
+ m->set_name_index(cp->utf8(name));
+ m->set_signature_index(cp->utf8(sig));
+ ResultTypeFinder rtf(sig);
+ m->constMethod()->set_result_type(rtf.type());
+ m->set_size_of_parameters(params);
+ m->set_max_stack(max_stack);
+ m->set_max_locals(params);
+ m->constMethod()->set_stackmap_data(NULL);
+ m->set_code(code_start);
+
+ return m;
+}
+
+static void switchover_constant_pool(BytecodeConstantPool* bpool,
+ InstanceKlass* klass, GrowableArray<Method*>* new_methods, TRAPS) {
+
+ if (new_methods->length() > 0) {
+ ConstantPool* cp = bpool->create_constant_pool(CHECK);
+ if (cp != klass->constants()) {
+ klass->class_loader_data()->add_to_deallocate_list(klass->constants());
+ klass->set_constants(cp);
+ cp->set_pool_holder(klass);
+
+ for (int i = 0; i < new_methods->length(); ++i) {
+ new_methods->at(i)->set_constants(cp);
+ }
+ for (int i = 0; i < klass->methods()->length(); ++i) {
+ Method* mo = klass->methods()->at(i);
+ mo->set_constants(cp);
+ }
+ }
+ }
+}
+
+// Create default_methods list for the current class.
+// With the VM only processing erased signatures, the VM only
+// creates an overpass in a conflict case or a case with no candidates.
+// This allows virtual methods to override the overpass, but ensures
+// that a local method search will find the exception rather than an abstract
+// or default method that is not a valid candidate.
+static void create_defaults_and_exceptions(
+ GrowableArray<EmptyVtableSlot*>* slots,
+ InstanceKlass* klass, TRAPS) {
+
+ GrowableArray<Method*> overpasses;
+ GrowableArray<Method*> defaults;
+ BytecodeConstantPool bpool(klass->constants());
+
+ for (int i = 0; i < slots->length(); ++i) {
+ EmptyVtableSlot* slot = slots->at(i);
+
+ if (slot->is_bound()) {
+ MethodFamily* method = slot->get_binding();
+ BytecodeBuffer buffer;
+
+ LogTarget(Debug, defaultmethods) lt;
+ if (lt.is_enabled()) {
+ ResourceMark rm(THREAD);
+ LogStream ls(lt);
+ ls.print("for slot: ");
+ slot->print_on(&ls);
+ ls.cr();
+ if (method->has_target()) {
+ method->print_selected(&ls, 1);
+ } else if (method->throws_exception()) {
+ method->print_exception(&ls, 1);
+ }
+ }
+
+ if (method->has_target()) {
+ Method* selected = method->get_selected_target();
+ if (selected->method_holder()->is_interface()) {
+ assert(!selected->is_private(), "pushing private interface method as default");
+ defaults.push(selected);
+ }
+ } else if (method->throws_exception()) {
+ int max_stack = assemble_method_error(&bpool, &buffer,
+ method->get_exception_name(), method->get_exception_message(), CHECK);
+ AccessFlags flags = accessFlags_from(
+ JVM_ACC_PUBLIC | JVM_ACC_SYNTHETIC | JVM_ACC_BRIDGE);
+ Method* m = new_method(&bpool, &buffer, slot->name(), slot->signature(),
+ flags, max_stack, slot->size_of_parameters(),
+ ConstMethod::OVERPASS, CHECK);
+ // We push to the methods list:
+ // overpass methods which are exception throwing methods
+ if (m != NULL) {
+ overpasses.push(m);
+ }
+ }
+ }
+ }
+
+
+ log_debug(defaultmethods)("Created %d overpass methods", overpasses.length());
+ log_debug(defaultmethods)("Created %d default methods", defaults.length());
+
+ if (overpasses.length() > 0) {
+ switchover_constant_pool(&bpool, klass, &overpasses, CHECK);
+ merge_in_new_methods(klass, &overpasses, CHECK);
+ }
+ if (defaults.length() > 0) {
+ create_default_methods(klass, &defaults, CHECK);
+ }
+}
+
+static void create_default_methods( InstanceKlass* klass,
+ GrowableArray<Method*>* new_methods, TRAPS) {
+
+ int new_size = new_methods->length();
+ Array<Method*>* total_default_methods = MetadataFactory::new_array<Method*>(
+ klass->class_loader_data(), new_size, NULL, CHECK);
+ for (int index = 0; index < new_size; index++ ) {
+ total_default_methods->at_put(index, new_methods->at(index));
+ }
+ Method::sort_methods(total_default_methods, false, false);
+
+ klass->set_default_methods(total_default_methods);
+}
+
+static void sort_methods(GrowableArray<Method*>* methods) {
+ // Note that this must sort using the same key as is used for sorting
+ // methods in InstanceKlass.
+ bool sorted = true;
+ for (int i = methods->length() - 1; i > 0; --i) {
+ for (int j = 0; j < i; ++j) {
+ Method* m1 = methods->at(j);
+ Method* m2 = methods->at(j + 1);
+ if ((uintptr_t)m1->name() > (uintptr_t)m2->name()) {
+ methods->at_put(j, m2);
+ methods->at_put(j + 1, m1);
+ sorted = false;
+ }
+ }
+ if (sorted) break;
+ sorted = true;
+ }
+#ifdef ASSERT
+ uintptr_t prev = 0;
+ for (int i = 0; i < methods->length(); ++i) {
+ Method* mh = methods->at(i);
+ uintptr_t nv = (uintptr_t)mh->name();
+ assert(nv >= prev, "Incorrect overpass method ordering");
+ prev = nv;
+ }
+#endif
+}
+
+static void merge_in_new_methods(InstanceKlass* klass,
+ GrowableArray<Method*>* new_methods, TRAPS) {
+
+ enum { ANNOTATIONS, PARAMETERS, DEFAULTS, NUM_ARRAYS };
+
+ Array<Method*>* original_methods = klass->methods();
+ Array<int>* original_ordering = klass->method_ordering();
+ Array<int>* merged_ordering = Universe::the_empty_int_array();
+
+ int new_size = klass->methods()->length() + new_methods->length();
+
+ Array<Method*>* merged_methods = MetadataFactory::new_array<Method*>(
+ klass->class_loader_data(), new_size, NULL, CHECK);
+
+ // original_ordering might be empty if this class has no methods of its own
+ if (JvmtiExport::can_maintain_original_method_order() || DumpSharedSpaces) {
+ merged_ordering = MetadataFactory::new_array<int>(
+ klass->class_loader_data(), new_size, CHECK);
+ }
+ int method_order_index = klass->methods()->length();
+
+ sort_methods(new_methods);
+
+ // Perform grand merge of existing methods and new methods
+ int orig_idx = 0;
+ int new_idx = 0;
+
+ for (int i = 0; i < new_size; ++i) {
+ Method* orig_method = NULL;
+ Method* new_method = NULL;
+ if (orig_idx < original_methods->length()) {
+ orig_method = original_methods->at(orig_idx);
+ }
+ if (new_idx < new_methods->length()) {
+ new_method = new_methods->at(new_idx);
+ }
+
+ if (orig_method != NULL &&
+ (new_method == NULL || orig_method->name() < new_method->name())) {
+ merged_methods->at_put(i, orig_method);
+ original_methods->at_put(orig_idx, NULL);
+ if (merged_ordering->length() > 0) {
+ assert(original_ordering != NULL && original_ordering->length() > 0,
+ "should have original order information for this method");
+ merged_ordering->at_put(i, original_ordering->at(orig_idx));
+ }
+ ++orig_idx;
+ } else {
+ merged_methods->at_put(i, new_method);
+ if (merged_ordering->length() > 0) {
+ merged_ordering->at_put(i, method_order_index++);
+ }
+ ++new_idx;
+ }
+ // update idnum for new location
+ merged_methods->at(i)->set_method_idnum(i);
+ merged_methods->at(i)->set_orig_method_idnum(i);
+ }
+
+ // Verify correct order
+#ifdef ASSERT
+ uintptr_t prev = 0;
+ for (int i = 0; i < merged_methods->length(); ++i) {
+ Method* mo = merged_methods->at(i);
+ uintptr_t nv = (uintptr_t)mo->name();
+ assert(nv >= prev, "Incorrect method ordering");
+ prev = nv;
+ }
+#endif
+
+ // Replace klass methods with new merged lists
+ klass->set_methods(merged_methods);
+ klass->set_initial_method_idnum(new_size);
+ klass->set_method_ordering(merged_ordering);
+
+ // Free metadata
+ ClassLoaderData* cld = klass->class_loader_data();
+ if (original_methods->length() > 0) {
+ MetadataFactory::free_array(cld, original_methods);
+ }
+ if (original_ordering != NULL && original_ordering->length() > 0) {
+ MetadataFactory::free_array(cld, original_ordering);
+ }
+}