jdk8-mips64-public/hotspot: comparison src/share/vm/classfile/defaultMethods.cpp

-:a1b8cf9cf970
+:4735d2c84362
+/*
+* Copyright (c) 2012, 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/genericSignatures.hpp"
+#include "classfile/symbolTable.hpp"
+#include "memory/allocation.hpp"
+#include "memory/metadataFactory.hpp"
+#include "memory/resourceArea.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();
+}
+}
+};
+class ContextMark : public PseudoScopeMark {
+private:
+generic::Context::Mark _mark;
+public:
+ContextMark(const generic::Context::Mark& cm) : _mark(cm) {}
+virtual void destroy() { _mark.destroy(); }
+};
+#ifndef PRODUCT
+static void print_slot(outputStream* str, Symbol* name, Symbol* signature) {
+ResourceMark rm;
+str->print("%s%s", name->as_C_string(), signature->as_C_string());
+}
+static void print_method(outputStream* str, Method* mo, bool with_class=true) {
+ResourceMark rm;
+if (with_class) {
+str->print("%s.", mo->klass_name()->as_C_string());
+}
+print_slot(str, mo->name(), mo->signature());
+}
+#endif // ndef PRODUCT
+/**
+* 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; }
+static bool has_super(InstanceKlass* cls) {
+return cls->super() != NULL && !cls->is_interface();
+}
+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());
+}
+};
+#ifndef PRODUCT
+class PrintHierarchy : public HierarchyVisitor<PrintHierarchy> {
+public:
+bool visit() {
+InstanceKlass* cls = current_class();
+streamIndentor si(tty, current_depth() * 2);
+tty->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; }
+};
+#endif // ndef PRODUCT
+// 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
+// language-level method.  Because of erasure, these methods may have different
+// signatures.  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
+// language-equivalent method defined in an interface.
+class MethodFamily : public ResourceObj {
+private:
+generic::MethodDescriptor* _descriptor; // language-level description
+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
+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);
+assert(index != NULL && *index >= 0 && *index < _members.length(), "bad index");
+_members.at(*index).second = DISQUALIFIED;
+}
+Symbol* generate_no_defaults_message(TRAPS) const;
+Symbol* generate_abstract_method_message(Method* method, TRAPS) const;
+Symbol* generate_conflicts_message(GrowableArray<Method*>* methods, TRAPS) const;
+public:
+MethodFamily(generic::MethodDescriptor* canonical_desc)
+: _descriptor(canonical_desc), _selected_target(NULL),
+_exception_message(NULL) {}
+generic::MethodDescriptor* descriptor() const { return _descriptor; }
+bool descriptor_matches(generic::MethodDescriptor* md, generic::Context* ctx) {
+return descriptor()->covariant_match(md, ctx);
+}
+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; }
+// Either sets the target or the exception error message
+void determine_target(InstanceKlass* root, TRAPS) {
+if (has_target() || throws_exception()) {
+return;
+}
+GrowableArray<Method*> qualified_methods;
+for (int i = 0; i < _members.length(); ++i) {
+Pair<Method*,QualifiedState> entry = _members.at(i);
+if (entry.second == QUALIFIED) {
+qualified_methods.append(entry.first);
+}
+}
+if (qualified_methods.length() == 0) {
+_exception_message = generate_no_defaults_message(CHECK);
+} else if (qualified_methods.length() == 1) {
+Method* method = qualified_methods.at(0);
+if (method->is_abstract()) {
+_exception_message = generate_abstract_method_message(method, CHECK);
+} else {
+_selected_target = qualified_methods.at(0);
+}
+} else {
+_exception_message = generate_conflicts_message(&qualified_methods,CHECK);
+}
+assert((has_target() ^ throws_exception()) == 1,
+"One and only one must be true");
+}
+bool contains_signature(Symbol* query) {
+for (int i = 0; i < _members.length(); ++i) {
+if (query == _members.at(i).first->signature()) {
+return true;
+}
+}
+return false;
+}
+#ifndef PRODUCT
+void print_on(outputStream* str) const {
+print_on(str, 0);
+}
+void print_on(outputStream* str, int indent) const {
+streamIndentor si(str, indent * 2);
+generic::Context ctx(NULL); // empty, as _descriptor already canonicalized
+TempNewSymbol family = descriptor()->reify_signature(&ctx, Thread::current());
+str->indent().print_cr("Logical Method %s:", family->as_C_string());
+streamIndentor si2(str);
+for (int i = 0; i < _members.length(); ++i) {
+str->indent();
+print_method(str, _members.at(i).first);
+if (_members.at(i).second == DISQUALIFIED) {
+str->print(" (disqualified)");
+}
+str->print_cr("");
+}
+if (_selected_target != NULL) {
+print_selected(str, 1);
+}
+}
+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);
+str->print_cr("");
+}
+void print_exception(outputStream* str, int indent) {
+assert(throws_exception(), "Should be called otherwise");
+streamIndentor si(str, indent * 2);
+str->indent().print_cr("%s", _exception_message->as_C_string());
+}
+#endif // ndef PRODUCT
+};
+Symbol* MethodFamily::generate_no_defaults_message(TRAPS) const {
+return SymbolTable::new_symbol("No qualifying defaults found", CHECK_NULL);
+}
+Symbol* MethodFamily::generate_abstract_method_message(Method* method, TRAPS) const {
+Symbol* klass = method->klass_name();
+Symbol* name = method->name();
+Symbol* sig = method->signature();
+stringStream ss;
+ss.print("Method ");
+ss.write((const char*)klass->bytes(), klass->utf8_length());
+ss.print(".");
+ss.write((const char*)name->bytes(), name->utf8_length());
+ss.write((const char*)sig->bytes(), sig->utf8_length());
+ss.print(" is abstract");
+return SymbolTable::new_symbol(ss.base(), (int)ss.size(), CHECK_NULL);
+}
+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(), CHECK_NULL);
+}
+class StateRestorer;
+// StatefulMethodFamily is a wrapper around 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:
+MethodFamily* _method;
+QualifiedState _qualification_state;
+void set_qualification_state(QualifiedState state) {
+_qualification_state = state;
+}
+public:
+StatefulMethodFamily(generic::MethodDescriptor* md, generic::Context* ctx) {
+_method = new MethodFamily(md->canonicalize(ctx));
+_qualification_state = QUALIFIED;
+}
+void set_target_if_empty(Method* m) { _method->set_target_if_empty(m); }
+MethodFamily* get_method_family() { return _method; }
+bool descriptor_matches(generic::MethodDescriptor* md, generic::Context* ctx) {
+return _method->descriptor_matches(md, ctx);
+}
+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->record_qualified_method(mo);
+} else {
+_method->record_disqualified_method(mo);
+}
+// Everything found "above"??? this method in the hierarchy walk is set to
+// disqualified
+set_qualification_state(DISQUALIFIED);
+return mark;
+}
+class StatefulMethodFamilies : public ResourceObj {
+private:
+GrowableArray<StatefulMethodFamily*> _methods;
+public:
+StatefulMethodFamily* find_matching(
+generic::MethodDescriptor* md, generic::Context* ctx) {
+for (int i = 0; i < _methods.length(); ++i) {
+StatefulMethodFamily* existing = _methods.at(i);
+if (existing->descriptor_matches(md, ctx)) {
+return existing;
+}
+}
+return NULL;
+}
+StatefulMethodFamily* find_matching_or_create(
+generic::MethodDescriptor* md, generic::Context* ctx) {
+StatefulMethodFamily* method = find_matching(md, ctx);
+if (method == NULL) {
+method = new StatefulMethodFamily(md, ctx);
+_methods.append(method);
+}
+return method;
+}
+void extract_families_into(GrowableArray<MethodFamily*>* array) {
+for (int i = 0; i < _methods.length(); ++i) {
+array->append(_methods.at(i)->get_method_family());
+}
+}
+};
+// 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; }
+#ifndef PRODUCT
+void print_on(outputStream* str) const {
+print_slot(str, name(), signature());
+}
+#endif // ndef PRODUCT
+};
+static GrowableArray<EmptyVtableSlot*>* find_empty_vtable_slots(
+InstanceKlass* klass, 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) {
+EmptyVtableSlot* slot = new EmptyVtableSlot(mirandas->at(i));
+slots->append(slot);
+}
+// 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 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()) {
+slots->append(new EmptyVtableSlot(m));
+}
+}
+}
+super = super->java_super();
+}
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+tty->print_cr("Slots that need filling:");
+streamIndentor si(tty);
+for (int i = 0; i < slots->length(); ++i) {
+tty->indent();
+slots->at(i)->print_on(tty);
+tty->print_cr("");
+}
+}
+#endif // ndef PRODUCT
+return slots;
+}
+// Iterates over the type hierarchy looking for all methods with a specific
+// method name.  The result of this is a set of method families each of
+// which is populated with a set of methods that implement the same
+// language-level signature.
+class FindMethodsByName : public HierarchyVisitor<FindMethodsByName> {
+private:
+// Context data
+Thread* THREAD;
+generic::DescriptorCache* _cache;
+Symbol* _method_name;
+generic::Context* _ctx;
+StatefulMethodFamilies _families;
+public:
+FindMethodsByName(generic::DescriptorCache* cache, Symbol* name,
+generic::Context* ctx, Thread* thread) :
+_cache(cache), _method_name(name), _ctx(ctx), THREAD(thread) {}
+void get_discovered_families(GrowableArray<MethodFamily*>* methods) {
+_families.extract_families_into(methods);
+}
+void* new_node_data(InstanceKlass* cls) { return new PseudoScope(); }
+void free_node_data(void* node_data) {
+PseudoScope::cast(node_data)->destroy();
+}
+bool visit() {
+PseudoScope* scope = PseudoScope::cast(current_data());
+InstanceKlass* klass = current_class();
+InstanceKlass* sub = current_depth() > 0 ? class_at_depth(1) : NULL;
+ContextMark* cm = new ContextMark(_ctx->mark());
+scope->add_mark(cm); // will restore context when scope is freed
+_ctx->apply_type_arguments(sub, klass, THREAD);
+int start, end = 0;
+start = klass->find_method_by_name(_method_name, &end);
+if (start != -1) {
+for (int i = start; i < end; ++i) {
+Method* m = klass->methods()->at(i);
+// This gets the method's parameter list with its generic type
+// parameters resolved
+generic::MethodDescriptor* md = _cache->descriptor_for(m, THREAD);
+// Find all methods on this hierarchy that match this method
+// (name, signature).   This class collects other families of this
+// method name.
+StatefulMethodFamily* family =
+_families.find_matching_or_create(md, _ctx);
+if (klass->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
+family->set_target_if_empty(m);
+}
+}
+}
+return true;
+}
+};
+#ifndef PRODUCT
+static void print_families(
+GrowableArray<MethodFamily*>* methods, Symbol* match) {
+streamIndentor si(tty, 4);
+if (methods->length() == 0) {
+tty->indent();
+tty->print_cr("No Logical Method found");
+}
+for (int i = 0; i < methods->length(); ++i) {
+tty->indent();
+MethodFamily* lm = methods->at(i);
+if (lm->contains_signature(match)) {
+tty->print_cr("<Matching>");
+} else {
+tty->print_cr("<Non-Matching>");
+}
+lm->print_on(tty, 1);
+}
+}
+#endif // ndef PRODUCT
+static void merge_in_new_methods(InstanceKlass* klass,
+GrowableArray<Method*>* new_methods, TRAPS);
+static void create_overpasses(
+GrowableArray<EmptyVtableSlot*>* slots, InstanceKlass* klass, 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, using generic signature
+// information to partition any methods that match the name into method families
+// where each family contains methods whose signatures are equivalent at the
+// language level (i.e., their reified parameters match and return values are
+// covariant). Check those sets to see if they contain a signature that matches
+// the slot we're looking at (if we're lucky, there might be other empty slots
+// that we can fill using the same analysis).
+//
+// 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.  If
+// the method set we're using contains methods (qualified or not) with a
+// different runtime signature than the method we're creating, then we have to
+// create bridges with those signatures too.
+void DefaultMethods::generate_default_methods(
+InstanceKlass* klass, GrowableArray<Method*>* mirandas, TRAPS) {
+// 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);
+generic::DescriptorCache cache;
+// Keep entire hierarchy alive for the duration of the computation
+KeepAliveRegistrar keepAlive(THREAD);
+KeepAliveVisitor loadKeepAlive(&keepAlive);
+loadKeepAlive.run(klass);
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+ResourceMark rm;  // be careful with these!
+tty->print_cr("Class %s requires default method processing",
+klass->name()->as_klass_external_name());
+PrintHierarchy printer;
+printer.run(klass);
+}
+#endif // ndef PRODUCT
+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);
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+streamIndentor si(tty, 2);
+tty->indent().print("Looking for default methods for slot ");
+slot->print_on(tty);
+tty->print_cr("");
+}
+#endif // ndef PRODUCT
+if (slot->is_bound()) {
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+streamIndentor si(tty, 4);
+tty->indent().print_cr("Already bound to logical method:");
+slot->get_binding()->print_on(tty, 1);
+}
+#endif // ndef PRODUCT
+continue; // covered by previous processing
+}
+generic::Context ctx(&cache);
+FindMethodsByName visitor(&cache, slot->name(), &ctx, CHECK);
+visitor.run(klass);
+GrowableArray<MethodFamily*> discovered_families;
+visitor.get_discovered_families(&discovered_families);
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+print_families(&discovered_families, slot->signature());
+}
+#endif // ndef PRODUCT
+// Find and populate any other slots that match the discovered families
+for (int j = i; j < empty_slots->length(); ++j) {
+EmptyVtableSlot* open_slot = empty_slots->at(j);
+if (slot->name() == open_slot->name()) {
+for (int k = 0; k < discovered_families.length(); ++k) {
+MethodFamily* lm = discovered_families.at(k);
+if (lm->contains_signature(open_slot->signature())) {
+lm->determine_target(klass, CHECK);
+open_slot->bind_family(lm);
+}
+}
+}
+}
+}
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+tty->print_cr("Creating overpasses...");
+}
+#endif // ndef PRODUCT
+create_overpasses(empty_slots, klass, CHECK);
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+tty->print_cr("Default method processing complete");
+}
+#endif // ndef PRODUCT
+}
+/**
+* Generic analysis was used upon interface '_target' and found a unique
+* default method candidate with generic signature '_method_desc'.  This
+* method is only viable if it would also be in the set of default method
+* candidates if we ran a full analysis on the current class.
+*
+* The only reason that the method would not be in the set of candidates for
+* the current class is if that there's another covariantly matching method
+* which is "more specific" than the found method -- i.e., one could find a
+* path in the interface hierarchy in which the matching method appears
+* before we get to '_target'.
+*
+* In order to determine this, we examine all of the implemented
+* interfaces.  If we find path that leads to the '_target' interface, then
+* we examine that path to see if there are any methods that would shadow
+* the selected method along that path.
+*/
+class ShadowChecker : public HierarchyVisitor<ShadowChecker> {
+private:
+generic::DescriptorCache* _cache;
+Thread* THREAD;
+InstanceKlass* _target;
+Symbol* _method_name;
+InstanceKlass* _method_holder;
+generic::MethodDescriptor* _method_desc;
+bool _found_shadow;
+bool path_has_shadow() {
+generic::Context ctx(_cache);
+for (int i = current_depth() - 1; i > 0; --i) {
+InstanceKlass* ik = class_at_depth(i);
+InstanceKlass* sub = class_at_depth(i + 1);
+ctx.apply_type_arguments(sub, ik, THREAD);
+if (ik->is_interface()) {
+int end;
+int start = ik->find_method_by_name(_method_name, &end);
+if (start != -1) {
+for (int j = start; j < end; ++j) {
+Method* mo = ik->methods()->at(j);
+generic::MethodDescriptor* md = _cache->descriptor_for(mo, THREAD);
+if (_method_desc->covariant_match(md, &ctx)) {
+return true;
+}
+}
+}
+}
+}
+return false;
+}
+public:
+ShadowChecker(generic::DescriptorCache* cache, Thread* thread,
+Symbol* name, InstanceKlass* holder, generic::MethodDescriptor* desc,
+InstanceKlass* target)
+: _cache(cache), THREAD(thread), _method_name(name), _method_holder(holder),
+_method_desc(desc), _target(target), _found_shadow(false) {}
+void* new_node_data(InstanceKlass* cls) { return NULL; }
+void free_node_data(void* data) { return; }
+bool visit() {
+InstanceKlass* ik = current_class();
+if (ik == _target && current_depth() == 1) {
+return false; // This was the specified super -- no need to search it
+}
+if (ik == _method_holder || ik == _target) {
+// We found a path that should be examined to see if it shadows _method
+if (path_has_shadow()) {
+_found_shadow = true;
+cancel_iteration();
+}
+return false; // no need to continue up hierarchy
+}
+return true;
+}
+bool found_shadow() { return _found_shadow; }
+};
+// This is called during linktime when we find an invokespecial call that
+// refers to a direct superinterface.  It indicates that we should find the
+// default method in the hierarchy of that superinterface, and if that method
+// would have been a candidate from the point of view of 'this' class, then we
+// return that method.
+Method* DefaultMethods::find_super_default(
+Klass* cls, Klass* super, Symbol* method_name, Symbol* sig, TRAPS) {
+ResourceMark rm(THREAD);
+assert(cls != NULL && super != NULL, "Need real classes");
+InstanceKlass* current_class = InstanceKlass::cast(cls);
+InstanceKlass* direction = InstanceKlass::cast(super);
+// Keep entire hierarchy alive for the duration of the computation
+KeepAliveRegistrar keepAlive(THREAD);
+KeepAliveVisitor loadKeepAlive(&keepAlive);
+loadKeepAlive.run(current_class);
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+tty->print_cr("Finding super default method %s.%s%s from %s",
+direction->name()->as_C_string(),
+method_name->as_C_string(), sig->as_C_string(),
+current_class->name()->as_C_string());
+}
+#endif // ndef PRODUCT
+if (!direction->is_interface()) {
+// We should not be here
+return NULL;
+}
+generic::DescriptorCache cache;
+generic::Context ctx(&cache);
+// Prime the initial generic context for current -> direction
+ctx.apply_type_arguments(current_class, direction, CHECK_NULL);
+FindMethodsByName visitor(&cache, method_name, &ctx, CHECK_NULL);
+visitor.run(direction);
+GrowableArray<MethodFamily*> families;
+visitor.get_discovered_families(&families);
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+print_families(&families, sig);
+}
+#endif // ndef PRODUCT
+MethodFamily* selected_family = NULL;
+for (int i = 0; i < families.length(); ++i) {
+MethodFamily* lm = families.at(i);
+if (lm->contains_signature(sig)) {
+lm->determine_target(current_class, CHECK_NULL);
+selected_family = lm;
+}
+}
+if (selected_family->has_target()) {
+Method* target = selected_family->get_selected_target();
+InstanceKlass* holder = InstanceKlass::cast(target->method_holder());
+// Verify that the identified method is valid from the context of
+// the current class
+ShadowChecker checker(&cache, THREAD, target->name(),
+holder, selected_family->descriptor(), direction);
+checker.run(current_class);
+if (checker.found_shadow()) {
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+tty->print_cr("    Only candidate found was shadowed.");
+}
+#endif // ndef PRODUCT
+THROW_MSG_(vmSymbols::java_lang_AbstractMethodError(),
+"Accessible default method not found", NULL);
+} else {
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+tty->print("    Returning ");
+print_method(tty, target, true);
+tty->print_cr("");
+}
+#endif // ndef PRODUCT
+return target;
+}
+} else {
+assert(selected_family->throws_exception(), "must have target or throw");
+THROW_MSG_(vmSymbols::java_lang_AbstractMethodError(),
+selected_family->get_exception_message()->as_C_string(), NULL);
+}
+}
+static int assemble_redirect(
+BytecodeConstantPool* cp, BytecodeBuffer* buffer,
+Symbol* incoming, Method* target, TRAPS) {
+BytecodeAssembler assem(buffer, cp);
+SignatureStream in(incoming, true);
+SignatureStream out(target->signature(), true);
+u2 parameter_count = 0;
+assem.aload(parameter_count++); // load 'this'
+while (!in.at_return_type()) {
+assert(!out.at_return_type(), "Parameter counts do not match");
+BasicType bt = in.type();
+assert(out.type() == bt, "Parameter types are not compatible");
+assem.load(bt, parameter_count);
+if (in.is_object() && in.as_symbol(THREAD) != out.as_symbol(THREAD)) {
+assem.checkcast(out.as_symbol(THREAD));
+} else if (bt == T_LONG || bt == T_DOUBLE) {
+++parameter_count; // longs and doubles use two slots
+}
+++parameter_count;
+in.next();
+out.next();
+}
+assert(out.at_return_type(), "Parameter counts do not match");
+assert(in.type() == out.type(), "Return types are not compatible");
+if (parameter_count == 1 && (in.type() == T_LONG || in.type() == T_DOUBLE)) {
+++parameter_count; // need room for return value
+}
+if (target->method_holder()->is_interface()) {
+assem.invokespecial(target);
+} else {
+assem.invokevirtual(target);
+}
+if (in.is_object() && in.as_symbol(THREAD) != out.as_symbol(THREAD)) {
+assem.checkcast(in.as_symbol(THREAD));
+}
+assem._return(in.type());
+return parameter_count;
+}
+static int assemble_abstract_method_error(
+BytecodeConstantPool* cp, BytecodeBuffer* buffer, Symbol* message, TRAPS) {
+Symbol* errorName = vmSymbols::java_lang_AbstractMethodError();
+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 = static_cast<address>(bytecodes->adr_at(0));
+int code_length = bytecodes->length();
+Method* m = Method::allocate(cp->pool_holder()->class_loader_data(),
+code_length, flags, 0, 0, 0, 0, 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));
+m->set_generic_signature_index(0);
+#ifdef CC_INTERP
+ResultTypeFinder rtf(sig);
+m->set_result_index(rtf.type());
+#endif
+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);
+m->set_force_inline(true);
+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);
+}
+}
+}
+}
+// A "bridge" is a method created by javac to bridge the gap between
+// an implementation and a generically-compatible, but different, signature.
+// Bridges have actual bytecode implementation in classfiles.
+// An "overpass", on the other hand, performs the same function as a bridge
+// but does not occur in a classfile; the VM creates overpass itself,
+// when it needs a path to get from a call site to an default method, and
+// a bridge doesn't exist.
+static void create_overpasses(
+GrowableArray<EmptyVtableSlot*>* slots,
+InstanceKlass* klass, TRAPS) {
+GrowableArray<Method*> overpasses;
+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();
+int max_stack = 0;
+BytecodeBuffer buffer;
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+tty->print("for slot: ");
+slot->print_on(tty);
+tty->print_cr("");
+if (method->has_target()) {
+method->print_selected(tty, 1);
+} else {
+method->print_exception(tty, 1);
+}
+}
+#endif // ndef PRODUCT
+if (method->has_target()) {
+Method* selected = method->get_selected_target();
+max_stack = assemble_redirect(
+&bpool, &buffer, slot->signature(), selected, CHECK);
+} else if (method->throws_exception()) {
+max_stack = assemble_abstract_method_error(
+&bpool, &buffer, 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);
+if (m != NULL) {
+overpasses.push(m);
+}
+}
+}
+#ifndef PRODUCT
+if (TraceDefaultMethods) {
+tty->print_cr("Created %d overpass methods", overpasses.length());
+}
+#endif // ndef PRODUCT
+switchover_constant_pool(&bpool, klass, &overpasses, CHECK);
+merge_in_new_methods(klass, &overpasses, CHECK);
+}
+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<AnnotationArray*>* original_annots[NUM_ARRAYS];
+Array<Method*>* original_methods = klass->methods();
+Annotations* annots = klass->annotations();
+original_annots[ANNOTATIONS] = annots->methods_annotations();
+original_annots[PARAMETERS]  = annots->methods_parameter_annotations();
+original_annots[DEFAULTS]    = annots->methods_default_annotations();
+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<AnnotationArray*>* merged_annots[NUM_ARRAYS];
+Array<Method*>* merged_methods = MetadataFactory::new_array<Method*>(
+klass->class_loader_data(), new_size, NULL, CHECK);
+for (int i = 0; i < NUM_ARRAYS; ++i) {
+if (original_annots[i] != NULL) {
+merged_annots[i] = MetadataFactory::new_array<AnnotationArray*>(
+klass->class_loader_data(), new_size, CHECK);
+} else {
+merged_annots[i] = NULL;
+}
+}
+if (original_ordering != NULL && original_ordering->length() > 0) {
+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);
+for (int j = 0; j < NUM_ARRAYS; ++j) {
+if (merged_annots[j] != NULL) {
+merged_annots[j]->at_put(i, original_annots[j]->at(orig_idx));
+original_annots[j]->at_put(orig_idx, NULL);
+}
+}
+if (merged_ordering->length() > 0) {
+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);
+}
+// 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);
+annots->set_methods_annotations(merged_annots[ANNOTATIONS]);
+annots->set_methods_parameter_annotations(merged_annots[PARAMETERS]);
+annots->set_methods_default_annotations(merged_annots[DEFAULTS]);
+ClassLoaderData* cld = klass->class_loader_data();
+MetadataFactory::free_array(cld, original_methods);
+for (int i = 0; i < NUM_ARRAYS; ++i) {
+MetadataFactory::free_array(cld, original_annots[i]);
+}
+if (original_ordering->length() > 0) {
+klass->set_method_ordering(merged_ordering);
+MetadataFactory::free_array(cld, original_ordering);
+}
+}

Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/classfile/defaultMethods.cpp

src/share/vm/classfile/defaultMethods.cpp