/* * Copyright (c) 1998, 2011, 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_CPCACHEOOP_HPP #define SHARE_VM_OOPS_CPCACHEOOP_HPP #include "interpreter/bytecodes.hpp" #include "memory/allocation.hpp" #include "oops/arrayOop.hpp" #include "utilities/array.hpp" // A ConstantPoolCacheEntry describes an individual entry of the constant // pool cache. There's 2 principal kinds of entries: field entries for in- // stance & static field access, and method entries for invokes. Some of // the entry layout is shared and looks as follows: // // bit number |31 0| // bit length |-8--|-8--|---16----| // -------------------------------- // _indices [ b2 | b1 | index ] // _f1 [ entry specific ] // _f2 [ entry specific ] // _flags [t|f|vf|v|m|h|unused|field_index] (for field entries) // bit length |4|1|1 |1|1|0|---7--|----16-----] // _flags [t|f|vf|v|m|h|unused|eidx|psze] (for method entries) // bit length |4|1|1 |1|1|1|---7--|-8--|-8--] // -------------------------------- // // with: // index = original constant pool index // b1 = bytecode 1 // b2 = bytecode 2 // psze = parameters size (method entries only) // eidx = interpreter entry index (method entries only) // field_index = index into field information in holder instanceKlass // The index max is 0xffff (max number of fields in constant pool) // and is multiplied by (instanceKlass::next_offset) when accessing. // t = TosState (see below) // f = field is marked final (see below) // vf = virtual, final (method entries only : is_vfinal()) // v = field is volatile (see below) // m = invokeinterface used for method in class Object (see below) // h = RedefineClasses/Hotswap bit (see below) // // The flags after TosState have the following interpretation: // bit 27: f flag true if field is marked final // bit 26: vf flag true if virtual final method // bit 25: v flag true if field is volatile (only for fields) // bit 24: m flag true if invokeinterface used for method in class Object // bit 23: 0 for fields, 1 for methods // // The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the // following mapping to the TosState states: // // btos: 0 // ctos: 1 // stos: 2 // itos: 3 // ltos: 4 // ftos: 5 // dtos: 6 // atos: 7 // vtos: 8 // // Entry specific: field entries: // _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index // _f1 = field holder // _f2 = field offset in words // _flags = field type information, original field index in field holder // (field_index section) // // Entry specific: method entries: // _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section), // original constant pool index // _f1 = method for all but virtual calls, unused by virtual calls // (note: for interface calls, which are essentially virtual, // contains klassOop for the corresponding interface. // for invokedynamic, f1 contains the CallSite object for the invocation // _f2 = method/vtable index for virtual calls only, unused by all other // calls. The vf flag indicates this is a method pointer not an // index. // _flags = field type info (f section), // virtual final entry (vf), // interpreter entry index (eidx section), // parameter size (psze section) // // Note: invokevirtual & invokespecial bytecodes can share the same constant // pool entry and thus the same constant pool cache entry. All invoke // bytecodes but invokevirtual use only _f1 and the corresponding b1 // bytecode, while invokevirtual uses only _f2 and the corresponding // b2 bytecode. The value of _flags is shared for both types of entries. // // The fields are volatile so that they are stored in the order written in the // source code. The _indices field with the bytecode must be written last. class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC { friend class VMStructs; friend class constantPoolCacheKlass; friend class constantPoolOopDesc; //resolve_constant_at_impl => set_f1 private: volatile intx _indices; // constant pool index & rewrite bytecodes volatile oop _f1; // entry specific oop field volatile intx _f2; // entry specific int/oop field volatile intx _flags; // flags #ifdef ASSERT bool same_methodOop(oop cur_f1, oop f1); #endif void set_bytecode_1(Bytecodes::Code code); void set_bytecode_2(Bytecodes::Code code); void set_f1(oop f1) { oop existing_f1 = _f1; // read once assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change"); oop_store(&_f1, f1); } void set_f1_if_null_atomic(oop f1); void set_f2(intx f2) { assert(_f2 == 0 || _f2 == f2, "illegal field change"); _f2 = f2; } int as_flags(TosState state, bool is_final, bool is_vfinal, bool is_volatile, bool is_method_interface, bool is_method); void set_flags(intx flags) { _flags = flags; } public: // specific bit values in flag field // Note: the interpreter knows this layout! enum FlagBitValues { hotSwapBit = 23, methodInterface = 24, volatileField = 25, vfinalMethod = 26, finalField = 27 }; enum { field_index_mask = 0xFFFF }; // start of type bits in flags // Note: the interpreter knows this layout! enum FlagValues { tosBits = 28 }; // Initialization void initialize_entry(int original_index); // initialize primary entry void initialize_secondary_entry(int main_index); // initialize secondary entry void set_field( // sets entry to resolved field state Bytecodes::Code get_code, // the bytecode used for reading the field Bytecodes::Code put_code, // the bytecode used for writing the field KlassHandle field_holder, // the object/klass holding the field int orig_field_index, // the original field index in the field holder int field_offset, // the field offset in words in the field holder TosState field_type, // the (machine) field type bool is_final, // the field is final bool is_volatile // the field is volatile ); void set_method( // sets entry to resolved method entry Bytecodes::Code invoke_code, // the bytecode used for invoking the method methodHandle method, // the method/prototype if any (NULL, otherwise) int vtable_index // the vtable index if any, else negative ); void set_interface_call( methodHandle method, // Resolved method int index // Method index into interface ); void set_dynamic_call( Handle call_site, // Resolved java.lang.invoke.CallSite (f1) methodHandle signature_invoker // determines signature information ); // For JVM_CONSTANT_InvokeDynamic cache entries: void initialize_bootstrap_method_index_in_cache(int bsm_cache_index); int bootstrap_method_index_in_cache(); void set_parameter_size(int value) { assert(parameter_size() == 0 || parameter_size() == value, "size must not change"); // Setting the parameter size by itself is only safe if the // current value of _flags is 0, otherwise another thread may have // updated it and we don't want to overwrite that value. Don't // bother trying to update it once it's nonzero but always make // sure that the final parameter size agrees with what was passed. if (_flags == 0) { Atomic::cmpxchg_ptr((value & 0xFF), &_flags, 0); } guarantee(parameter_size() == value, "size must not change"); } // Which bytecode number (1 or 2) in the index field is valid for this bytecode? // Returns -1 if neither is valid. static int bytecode_number(Bytecodes::Code code) { switch (code) { case Bytecodes::_getstatic : // fall through case Bytecodes::_getfield : // fall through case Bytecodes::_invokespecial : // fall through case Bytecodes::_invokestatic : // fall through case Bytecodes::_invokedynamic : // fall through case Bytecodes::_invokeinterface : return 1; case Bytecodes::_putstatic : // fall through case Bytecodes::_putfield : // fall through case Bytecodes::_invokevirtual : return 2; default : break; } return -1; } // Has this bytecode been resolved? Only valid for invokes and get/put field/static. bool is_resolved(Bytecodes::Code code) const { switch (bytecode_number(code)) { case 1: return (bytecode_1() == code); case 2: return (bytecode_2() == code); } return false; // default: not resolved } // Accessors bool is_secondary_entry() const { return (_indices & 0xFFFF) == 0; } int constant_pool_index() const { assert((_indices & 0xFFFF) != 0, "must be main entry"); return (_indices & 0xFFFF); } int main_entry_index() const { assert((_indices & 0xFFFF) == 0, "must be secondary entry"); return ((uintx)_indices >> 16); } Bytecodes::Code bytecode_1() const { return Bytecodes::cast((_indices >> 16) & 0xFF); } Bytecodes::Code bytecode_2() const { return Bytecodes::cast((_indices >> 24) & 0xFF); } volatile oop f1() const { return _f1; } bool is_f1_null() const { return (oop)_f1 == NULL; } // classifies a CPC entry as unbound intx f2() const { return _f2; } int field_index() const; int parameter_size() const { return _flags & 0xFF; } bool is_vfinal() const { return ((_flags & (1 << vfinalMethod)) == (1 << vfinalMethod)); } bool is_volatile() const { return ((_flags & (1 << volatileField)) == (1 << volatileField)); } bool is_methodInterface() const { return ((_flags & (1 << methodInterface)) == (1 << methodInterface)); } bool is_byte() const { return (((uintx) _flags >> tosBits) == btos); } bool is_char() const { return (((uintx) _flags >> tosBits) == ctos); } bool is_short() const { return (((uintx) _flags >> tosBits) == stos); } bool is_int() const { return (((uintx) _flags >> tosBits) == itos); } bool is_long() const { return (((uintx) _flags >> tosBits) == ltos); } bool is_float() const { return (((uintx) _flags >> tosBits) == ftos); } bool is_double() const { return (((uintx) _flags >> tosBits) == dtos); } bool is_object() const { return (((uintx) _flags >> tosBits) == atos); } TosState flag_state() const { assert( ( (_flags >> tosBits) & 0x0F ) < number_of_states, "Invalid state in as_flags"); return (TosState)((_flags >> tosBits) & 0x0F); } // Code generation support static WordSize size() { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); } static ByteSize size_in_bytes() { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); } static ByteSize indices_offset() { return byte_offset_of(ConstantPoolCacheEntry, _indices); } static ByteSize f1_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f1); } static ByteSize f2_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f2); } static ByteSize flags_offset() { return byte_offset_of(ConstantPoolCacheEntry, _flags); } // GC Support void oops_do(void f(oop*)); void oop_iterate(OopClosure* blk); void oop_iterate_m(OopClosure* blk, MemRegion mr); void follow_contents(); void adjust_pointers(); #ifndef SERIALGC // Parallel Old void follow_contents(ParCompactionManager* cm); #endif // SERIALGC void update_pointers(); // RedefineClasses() API support: // If this constantPoolCacheEntry refers to old_method then update it // to refer to 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_method_entry(methodOop old_method, methodOop new_method, bool * trace_name_printed); bool is_interesting_method_entry(klassOop k); bool is_field_entry() const { return (_flags & (1 << hotSwapBit)) == 0; } bool is_method_entry() const { return (_flags & (1 << hotSwapBit)) != 0; } // Debugging & Printing void print (outputStream* st, int index) const; void verify(outputStream* st) const; static void verify_tosBits() { assert(tosBits == 28, "interpreter now assumes tosBits is 28"); } }; // A constant pool cache is a runtime data structure set aside to a constant pool. The cache // holds interpreter runtime information for all field access and invoke bytecodes. The cache // is created and initialized before a class is actively used (i.e., initialized), the indivi- // dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*). class constantPoolCacheOopDesc: public oopDesc { friend class VMStructs; private: int _length; constantPoolOop _constant_pool; // the corresponding constant pool // Sizing debug_only(friend class ClassVerifier;) public: int length() const { return _length; } private: void set_length(int length) { _length = length; } static int header_size() { return sizeof(constantPoolCacheOopDesc) / HeapWordSize; } static int object_size(int length) { return align_object_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); } int object_size() { return object_size(length()); } // Helpers constantPoolOop* constant_pool_addr() { return &_constant_pool; } ConstantPoolCacheEntry* base() const { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); } friend class constantPoolCacheKlass; friend class ConstantPoolCacheEntry; public: // Initialization void initialize(intArray& inverse_index_map); // Secondary indexes. // They must look completely different from normal indexes. // The main reason is that byte swapping is sometimes done on normal indexes. // Also, some of the CP accessors do different things for secondary indexes. // Finally, it is helpful for debugging to tell the two apart. static bool is_secondary_index(int i) { return (i < 0); } static int decode_secondary_index(int i) { assert(is_secondary_index(i), ""); return ~i; } static int encode_secondary_index(int i) { assert(!is_secondary_index(i), ""); return ~i; } // Accessors void set_constant_pool(constantPoolOop pool) { oop_store_without_check((oop*)&_constant_pool, (oop)pool); } constantPoolOop constant_pool() const { return _constant_pool; } // Fetches the entry at the given index. // The entry may be either primary or secondary. // In either case the index must not be encoded or byte-swapped in any way. ConstantPoolCacheEntry* entry_at(int i) const { assert(0 <= i && i < length(), "index out of bounds"); return base() + i; } // Fetches the secondary entry referred to by index. // The index may be a secondary index, and must not be byte-swapped. ConstantPoolCacheEntry* secondary_entry_at(int i) const { int raw_index = i; if (is_secondary_index(i)) { // correct these on the fly raw_index = decode_secondary_index(i); } assert(entry_at(raw_index)->is_secondary_entry(), "not a secondary entry"); return entry_at(raw_index); } // Given a primary or secondary index, fetch the corresponding primary entry. // Indirect through the secondary entry, if the index is encoded as a secondary index. // The index must not be byte-swapped. ConstantPoolCacheEntry* main_entry_at(int i) const { int primary_index = i; if (is_secondary_index(i)) { // run through an extra level of indirection: int raw_index = decode_secondary_index(i); primary_index = entry_at(raw_index)->main_entry_index(); } assert(!entry_at(primary_index)->is_secondary_entry(), "only one level of indirection"); return entry_at(primary_index); } // Code generation static ByteSize base_offset() { return in_ByteSize(sizeof(constantPoolCacheOopDesc)); } static ByteSize entry_offset(int raw_index) { int index = raw_index; if (is_secondary_index(raw_index)) index = decode_secondary_index(raw_index); return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index); } // RedefineClasses() API support: // If any entry of this constantPoolCache 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(methodOop* old_methods, methodOop* new_methods, int methods_length, bool * trace_name_printed); }; #endif // SHARE_VM_OOPS_CPCACHEOOP_HPP