| /* |
| * 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/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(); |
| } |
| } |
| }; |
| |
| #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 |
| // 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 |
| |
| 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() |
| : _selected_target(NULL), _exception_message(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; } |
| |
| // 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_sig_on(outputStream* str, Symbol* signature, int indent) const { |
| streamIndentor si(str, indent * 2); |
| |
| str->indent().print_cr("Logical Method %s:", signature->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 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; } |
| |
| #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 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); |
| if (m != NULL) { |
| 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 |
| _family->set_target_if_empty(m); |
| } |
| } |
| return true; |
| } |
| |
| }; |
| |
| |
| |
| static void create_overpasses( |
| 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); |
| |
| // 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, 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); |
| |
| // 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 |
| |
| generate_erased_defaults(klass, empty_slots, slot, CHECK); |
| } |
| #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 |
| } |
| |
| /** |
| * Interface inheritance rules were used to find a unique default method |
| * candidate for the resolved class. 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 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> { |
| protected: |
| Thread* THREAD; |
| |
| InstanceKlass* _target; |
| |
| Symbol* _method_name; |
| InstanceKlass* _method_holder; |
| bool _found_shadow; |
| |
| |
| public: |
| |
| ShadowChecker(Thread* thread, Symbol* name, InstanceKlass* holder, |
| InstanceKlass* target) |
| : THREAD(thread), _method_name(name), _method_holder(holder), |
| _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; |
| } |
| |
| virtual bool path_has_shadow() = 0; |
| bool found_shadow() { return _found_shadow; } |
| }; |
| |
| // Used for Invokespecial. |
| // Invokespecial is allowed to invoke a concrete interface method |
| // and can be used to disambuiguate among qualified candidates, |
| // which are methods in immediate superinterfaces, |
| // but may not be used to invoke a candidate that would be shadowed |
| // from the perspective of the caller. |
| // Invokespecial is also used in the overpass generation today |
| // We re-run the shadowchecker because we can't distinguish this case, |
| // but it should return the same answer, since the overpass target |
| // is now the invokespecial caller. |
| class ErasedShadowChecker : public ShadowChecker { |
| private: |
| bool path_has_shadow() { |
| |
| for (int i = current_depth() - 1; i > 0; --i) { |
| InstanceKlass* ik = class_at_depth(i); |
| |
| if (ik->is_interface()) { |
| int end; |
| int start = ik->find_method_by_name(_method_name, &end); |
| if (start != -1) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| public: |
| |
| ErasedShadowChecker(Thread* thread, Symbol* name, InstanceKlass* holder, |
| InstanceKlass* target) |
| : ShadowChecker(thread, name, holder, target) {} |
| }; |
| |
| // Find the unique qualified candidate from the perspective of the super_class |
| // which is the resolved_klass, which must be an immediate superinterface |
| // of klass |
| Method* find_erased_super_default(InstanceKlass* current_class, InstanceKlass* super_class, Symbol* method_name, Symbol* sig, TRAPS) { |
| |
| FindMethodsByErasedSig visitor(method_name, sig); |
| visitor.run(super_class); // find candidates from resolved_klass |
| |
| MethodFamily* family; |
| visitor.get_discovered_family(&family); |
| |
| if (family != NULL) { |
| family->determine_target(current_class, CHECK_NULL); // get target from current_class |
| |
| if (family->has_target()) { |
| Method* target = 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, which is the caller class for invokespecial |
| // link resolution, i.e. ensure there it is not shadowed. |
| // You can use invokespecial to disambiguate interface methods, but |
| // you can not use it to skip over an interface method that would shadow it. |
| ErasedShadowChecker checker(THREAD, target->name(), holder, super_class); |
| 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) { |
| family->print_sig_on(tty, target->signature(), 1); |
| } |
| #endif // ndef PRODUCT |
| return target; |
| } |
| } else { |
| assert(family->throws_exception(), "must have target or throw"); |
| THROW_MSG_(vmSymbols::java_lang_AbstractMethodError(), |
| family->get_exception_message()->as_C_string(), NULL); |
| } |
| } else { |
| // no method found |
| ResourceMark rm(THREAD); |
| THROW_MSG_(vmSymbols::java_lang_NoSuchMethodError(), |
| Method::name_and_sig_as_C_string(current_class, |
| method_name, sig), NULL); |
| } |
| } |
| // 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. |
| // This logic assumes that the super is a direct superclass of the caller |
| 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* super_class = InstanceKlass::cast(super); |
| |
| // Keep entire hierarchy alive for the duration of the computation |
| KeepAliveRegistrar keepAlive(THREAD); |
| KeepAliveVisitor loadKeepAlive(&keepAlive); |
| loadKeepAlive.run(current_class); // get hierarchy from current class |
| |
| #ifndef PRODUCT |
| if (TraceDefaultMethods) { |
| tty->print_cr("Finding super default method %s.%s%s from %s", |
| super_class->name()->as_C_string(), |
| method_name->as_C_string(), sig->as_C_string(), |
| current_class->name()->as_C_string()); |
| } |
| #endif // ndef PRODUCT |
| |
| assert(super_class->is_interface(), "only call for default methods"); |
| |
| Method* target = NULL; |
| target = find_erased_super_default(current_class, super_class, |
| method_name, sig, CHECK_NULL); |
| |
| #ifndef PRODUCT |
| if (target != NULL) { |
| if (TraceDefaultMethods) { |
| tty->print(" Returning "); |
| print_method(tty, target, true); |
| tty->print_cr(""); |
| } |
| } |
| #endif // ndef PRODUCT |
| return target; |
| } |
| |
| #ifndef PRODUCT |
| // Return true is broad type is a covariant return of narrow type |
| static bool covariant_return_type(BasicType narrow, BasicType broad) { |
| if (narrow == broad) { |
| return true; |
| } |
| if (broad == T_OBJECT) { |
| return true; |
| } |
| return false; |
| } |
| #endif // ndef PRODUCT |
| |
| 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(covariant_return_type(out.type(), in.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 = 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)); |
| #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); |
| } |
| } |
| |