/* * Copyright (c) 1997, 2018, 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. * */ #ifndef SHARE_VM_OOPS_KLASSVTABLE_HPP #define SHARE_VM_OOPS_KLASSVTABLE_HPP #include "oops/oopsHierarchy.hpp" #include "runtime/handles.hpp" #include "utilities/growableArray.hpp" // A klassVtable abstracts the variable-length vtable that is embedded in InstanceKlass // and ArrayKlass. klassVtable objects are used just as convenient transient accessors to the vtable, // not to actually hold the vtable data. // Note: the klassVtable should not be accessed before the class has been verified // (until that point, the vtable is uninitialized). // Currently a klassVtable contains a direct reference to the vtable data, and is therefore // not preserved across GCs. class vtableEntry; class klassVtable { Klass* _klass; // my klass int _tableOffset; // offset of start of vtable data within klass int _length; // length of vtable (number of entries) #ifndef PRODUCT int _verify_count; // to make verify faster #endif // Ordering important, so greater_than (>) can be used as an merge operator. enum AccessType { acc_private = 0, acc_package_private = 1, acc_publicprotected = 2 }; public: klassVtable(Klass* klass, void* base, int length) : _klass(klass) { _tableOffset = (address)base - (address)klass; _length = length; } // accessors vtableEntry* table() const { return (vtableEntry*)(address(_klass) + _tableOffset); } Klass* klass() const { return _klass; } int length() const { return _length; } inline Method* method_at(int i) const; inline Method* unchecked_method_at(int i) const; inline Method** adr_method_at(int i) const; // searching; all methods return -1 if not found int index_of(Method* m) const { return index_of(m, _length); } int index_of_miranda(Symbol* name, Symbol* signature); void initialize_vtable(bool checkconstraints, TRAPS); // initialize vtable of a new klass // CDS/RedefineClasses support - clear vtables so they can be reinitialized // at dump time. Clearing gives us an easy way to tell if the vtable has // already been reinitialized at dump time (see dump.cpp). Vtables can // be initialized at run time by RedefineClasses so dumping the right order // is necessary. void clear_vtable(); bool is_initialized(); // computes vtable length (in words) and the number of miranda methods static void compute_vtable_size_and_num_mirandas(int* vtable_length, int* num_new_mirandas, GrowableArray* all_mirandas, const Klass* super, Array* methods, AccessFlags class_flags, u2 major_version, Handle classloader, Symbol* classname, Array* local_interfaces, TRAPS); #if INCLUDE_JVMTI // RedefineClasses() API support: // If any entry of this vtable points to any of old_methods, // replace it with the corresponding new_method. // trace_name_printed is set to true if the current call has // printed the klass name so that other routines in the adjust_* // group don't print the klass name. bool adjust_default_method(int vtable_index, Method* old_method, Method* new_method); void adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed); bool check_no_old_or_obsolete_entries(); void dump_vtable(); #endif // INCLUDE_JVMTI // Debugging code void print() PRODUCT_RETURN; void verify(outputStream* st, bool force = false); static void print_statistics() PRODUCT_RETURN; protected: friend class vtableEntry; public: // Transitive overridng rules for class files < JDK1_7 use the older JVMS rules. // Overriding is determined as we create the vtable, so we use the class file version // of the class whose vtable we are calculating. enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ; private: void copy_vtable_to(vtableEntry* start); int initialize_from_super(Klass* super); int index_of(Method* m, int len) const; // same as index_of, but search only up to len void put_method_at(Method* m, int index); static bool needs_new_vtable_entry(const methodHandle& m, const Klass* super, Handle classloader, Symbol* classname, AccessFlags access_flags, u2 major_version, TRAPS); bool update_inherited_vtable(InstanceKlass* klass, const methodHandle& target_method, int super_vtable_len, int default_index, bool checkconstraints, TRAPS); InstanceKlass* find_transitive_override(InstanceKlass* initialsuper, const methodHandle& target_method, int vtable_index, Handle target_loader, Symbol* target_classname, Thread* THREAD); // support for miranda methods bool is_miranda_entry_at(int i); int fill_in_mirandas(int initialized); static bool is_miranda(Method* m, Array* class_methods, Array* default_methods, const Klass* super, bool is_interface); static void add_new_mirandas_to_lists( GrowableArray* new_mirandas, GrowableArray* all_mirandas, Array* current_interface_methods, Array* class_methods, Array* default_methods, const Klass* super, bool is_interface); static void get_mirandas( GrowableArray* new_mirandas, GrowableArray* all_mirandas, const Klass* super, Array* class_methods, Array* default_methods, Array* local_interfaces, bool is_interface); void verify_against(outputStream* st, klassVtable* vt, int index); inline InstanceKlass* ik() const; // When loading a class from CDS archive at run time, and no class redefintion // has happened, it is expected that the class's itable/vtables are // laid out exactly the same way as they had been during dump time. // Therefore, in klassVtable::initialize_[iv]table, we do not layout the // tables again. Instead, we only rerun the process to create/check // the class loader constraints. In non-product builds, we add asserts to // guarantee that the table's layout would be the same as at dump time. // // If JVMTI redefines any class, the read-only shared memory are remapped // as read-write. A shared class' vtable/itable are re-initialized and // might have different layout due to class redefinition of the shared class // or its super types. bool is_preinitialized_vtable(); }; // private helper class for klassVtable // description of entry points: // destination is interpreted: // from_compiled_code_entry_point -> c2iadapter // from_interpreter_entry_point -> interpreter entry point // destination is compiled: // from_compiled_code_entry_point -> nmethod entry point // from_interpreter_entry_point -> i2cadapter class vtableEntry { friend class VMStructs; friend class JVMCIVMStructs; public: // size in words static int size() { return sizeof(vtableEntry) / wordSize; } static int size_in_bytes() { return sizeof(vtableEntry); } static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); } Method* method() const { return _method; } Method** method_addr() { return &_method; } private: Method* _method; void set(Method* method) { assert(method != NULL, "use clear"); _method = method; } void clear() { _method = NULL; } void print() PRODUCT_RETURN; void verify(klassVtable* vt, outputStream* st); friend class klassVtable; }; inline Method* klassVtable::method_at(int i) const { assert(i >= 0 && i < _length, "index out of bounds"); assert(table()[i].method() != NULL, "should not be null"); assert(((Metadata*)table()[i].method())->is_method(), "should be method"); return table()[i].method(); } inline Method* klassVtable::unchecked_method_at(int i) const { assert(i >= 0 && i < _length, "index out of bounds"); return table()[i].method(); } inline Method** klassVtable::adr_method_at(int i) const { // Allow one past the last entry to be referenced; useful for loop bounds. assert(i >= 0 && i <= _length, "index out of bounds"); return (Method**)(address(table() + i) + vtableEntry::method_offset_in_bytes()); } // -------------------------------------------------------------------------------- class klassItable; class itableMethodEntry; class itableOffsetEntry { private: Klass* _interface; int _offset; public: Klass* interface_klass() const { return _interface; } Klass**interface_klass_addr() { return &_interface; } int offset() const { return _offset; } static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); } itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); } void initialize(Klass* interf, int offset) { _interface = interf; _offset = offset; } // Static size and offset accessors static int size() { return sizeof(itableOffsetEntry) / wordSize; } // size in words static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); } static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); } friend class klassItable; }; class itableMethodEntry { private: Method* _method; public: Method* method() const { return _method; } Method**method_addr() { return &_method; } void clear() { _method = NULL; } void initialize(Method* method); // Static size and offset accessors static int size() { return sizeof(itableMethodEntry) / wordSize; } // size in words static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); } friend class klassItable; }; // // Format of an itable // // ---- offset table --- // Klass* of interface 1 \ // offset to vtable from start of oop / offset table entry // ... // Klass* of interface n \ // offset to vtable from start of oop / offset table entry // --- vtable for interface 1 --- // Method* \ // compiler entry point / method table entry // ... // Method* \ // compiler entry point / method table entry // -- vtable for interface 2 --- // ... // class klassItable { private: InstanceKlass* _klass; // my klass int _table_offset; // offset of start of itable data within klass (in words) int _size_offset_table; // size of offset table (in itableOffset entries) int _size_method_table; // size of methodtable (in itableMethodEntry entries) void initialize_itable_for_interface(int method_table_offset, Klass* interf_h, bool checkconstraints, TRAPS); public: klassItable(InstanceKlass* klass); itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds"); return &((itableOffsetEntry*)vtable_start())[i]; } itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds"); return &((itableMethodEntry*)method_start())[i]; } int size_offset_table() { return _size_offset_table; } // Initialization void initialize_itable(bool checkconstraints, TRAPS); #if INCLUDE_JVMTI // RedefineClasses() API support: // if any entry of this itable points to any of old_methods, // replace it with the corresponding new_method. // trace_name_printed is set to true if the current call has // printed the klass name so that other routines in the adjust_* // group don't print the klass name. void adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed); bool check_no_old_or_obsolete_entries(); void dump_itable(); #endif // INCLUDE_JVMTI // Setup of itable static int assign_itable_indices_for_interface(Klass* klass); static int method_count_for_interface(Klass* klass); static int compute_itable_size(Array* transitive_interfaces); static void setup_itable_offset_table(InstanceKlass* klass); // Resolving of method to index static Method* method_for_itable_index(Klass* klass, int itable_index); // Debugging/Statistics static void print_statistics() PRODUCT_RETURN; private: intptr_t* vtable_start() const { return ((intptr_t*)_klass) + _table_offset; } intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); } // Helper methods static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); } // Statistics NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; }) }; #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP