Mercurial > hg > graal-compiler
view src/share/vm/classfile/defaultMethods.cpp @ 10503:2393c37d1997
Merge
author | Christos Kotselidis <christos.kotselidis@oracle.com> |
---|---|
date | Fri, 21 Jun 2013 23:12:51 +0200 |
parents | fe00365c8f31 |
children | 50257d6f5aaa |
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/* * Copyright (c) 2012, 2013, 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); guarantee(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(); InlineTableSizes sizes; 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)); #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<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); 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); 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); klass->set_initial_method_idnum(new_size); ClassLoaderData* cld = klass->class_loader_data(); MetadataFactory::free_array(cld, original_methods); if (original_ordering->length() > 0) { klass->set_method_ordering(merged_ordering); MetadataFactory::free_array(cld, original_ordering); } }