1 /*
   2  * Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  24 
  25 #ifndef SHARE_VM_OOPS_CPCACHEOOP_HPP
  26 #define SHARE_VM_OOPS_CPCACHEOOP_HPP
  27 
  28 #include "interpreter/bytecodes.hpp"
  29 #include "memory/allocation.hpp"
  30 #include "runtime/orderAccess.hpp"
  31 #include "utilities/array.hpp"
  32 
  33 class PSPromotionManager;
  34 
  35 // The ConstantPoolCache is not a cache! It is the resolution table that the
  36 // interpreter uses to avoid going into the runtime and a way to access resolved
  37 // values.
  38 
  39 // A ConstantPoolCacheEntry describes an individual entry of the constant
  40 // pool cache. There's 2 principal kinds of entries: field entries for in-
  41 // stance & static field access, and method entries for invokes. Some of
  42 // the entry layout is shared and looks as follows:
  43 //
  44 // bit number |31                0|
  45 // bit length |-8--|-8--|---16----|
  46 // --------------------------------
  47 // _indices   [ b2 | b1 |  index  ]  index = constant_pool_index
  48 // _f1        [  entry specific   ]  metadata ptr (method or klass)
  49 // _f2        [  entry specific   ]  vtable or res_ref index, or vfinal method ptr
  50 // _flags     [tos|0|F=1|0|0|0|f|v|0 |0000|field_index] (for field entries)
  51 // bit length [ 4 |1| 1 |1|1|1|1|1|1 |-4--|----16-----]
  52 // _flags     [tos|0|F=0|M|A|I|f|0|vf|0000|00000|psize] (for method entries)
  53 // bit length [ 4 |1| 1 |1|1|1|1|1|1 |-4--|--8--|--8--]
  54 
  55 // --------------------------------
  56 //
  57 // with:
  58 // index  = original constant pool index
  59 // b1     = bytecode 1
  60 // b2     = bytecode 2
  61 // psize  = parameters size (method entries only)
  62 // field_index = index into field information in holder InstanceKlass
  63 //          The index max is 0xffff (max number of fields in constant pool)
  64 //          and is multiplied by (InstanceKlass::next_offset) when accessing.
  65 // tos    = TosState
  66 // F      = the entry is for a field (or F=0 for a method)
  67 // A      = call site has an appendix argument (loaded from resolved references)
  68 // I      = interface call is forced virtual (must use a vtable index or vfinal)
  69 // f      = field or method is final
  70 // v      = field is volatile
  71 // vf     = virtual but final (method entries only: is_vfinal())
  72 //
  73 // The flags after TosState have the following interpretation:
  74 // bit 27: 0 for fields, 1 for methods
  75 // f  flag true if field is marked final
  76 // v  flag true if field is volatile (only for fields)
  77 // f2 flag true if f2 contains an oop (e.g., virtual final method)
  78 // fv flag true if invokeinterface used for method in class Object
  79 //
  80 // The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the
  81 // following mapping to the TosState states:
  82 //
  83 // btos: 0
  84 // ctos: 1
  85 // stos: 2
  86 // itos: 3
  87 // ltos: 4
  88 // ftos: 5
  89 // dtos: 6
  90 // atos: 7
  91 // vtos: 8
  92 //
  93 // Entry specific: field entries:
  94 // _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index
  95 // _f1      = field holder (as a java.lang.Class, not a Klass*)
  96 // _f2      = field offset in bytes
  97 // _flags   = field type information, original FieldInfo index in field holder
  98 //            (field_index section)
  99 //
 100 // Entry specific: method entries:
 101 // _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section),
 102 //            original constant pool index
 103 // _f1      = Method* for non-virtual calls, unused by virtual calls.
 104 //            for interface calls, which are essentially virtual but need a klass,
 105 //            contains Klass* for the corresponding interface.
 106 //            for invokedynamic and invokehandle, f1 contains the adapter method which
 107 //            manages the actual call. The appendix is stored in the ConstantPool
 108 //            resolved_references array.
 109 //            (upcoming metadata changes will move the appendix to a separate array)
 110 // _f2      = vtable/itable index (or final Method*) for virtual calls only,
 111 //            unused by non-virtual.  The is_vfinal flag indicates this is a
 112 //            method pointer for a final method, not an index.
 113 // _flags   = method type info (t section),
 114 //            virtual final bit (vfinal),
 115 //            parameter size (psize section)
 116 //
 117 // Note: invokevirtual & invokespecial bytecodes can share the same constant
 118 //       pool entry and thus the same constant pool cache entry. All invoke
 119 //       bytecodes but invokevirtual use only _f1 and the corresponding b1
 120 //       bytecode, while invokevirtual uses only _f2 and the corresponding
 121 //       b2 bytecode.  The value of _flags is shared for both types of entries.
 122 //
 123 // The fields are volatile so that they are stored in the order written in the
 124 // source code.  The _indices field with the bytecode must be written last.
 125 
 126 class CallInfo;
 127 
 128 class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC {
 129   friend class VMStructs;
 130   friend class constantPoolCacheKlass;
 131   friend class ConstantPool;
 132   friend class InterpreterRuntime;
 133 
 134  private:
 135   volatile intx     _indices;  // constant pool index & rewrite bytecodes
 136   volatile Metadata*   _f1;       // entry specific metadata field
 137   volatile intx        _f2;       // entry specific int/metadata field
 138   volatile intx     _flags;    // flags
 139 
 140 
 141   void set_bytecode_1(Bytecodes::Code code);
 142   void set_bytecode_2(Bytecodes::Code code);
 143   void set_f1(Metadata* f1) {
 144     Metadata* existing_f1 = (Metadata*)_f1; // read once
 145     assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change");
 146     _f1 = f1;
 147   }
 148   void release_set_f1(Metadata* f1);
 149   void set_f2(intx f2) {
 150     intx existing_f2 = _f2; // read once
 151     assert(existing_f2 == 0 || existing_f2 == f2, "illegal field change");
 152     _f2 = f2;
 153   }
 154   void set_f2_as_vfinal_method(Method* f2) {
 155     assert(is_vfinal(), "flags must be set");
 156     set_f2((intx)f2);
 157   }
 158   int make_flags(TosState state, int option_bits, int field_index_or_method_params);
 159   void set_flags(intx flags)                     { _flags = flags; }
 160   bool init_flags_atomic(intx flags);
 161   void set_field_flags(TosState field_type, int option_bits, int field_index) {
 162     assert((field_index & field_index_mask) == field_index, "field_index in range");
 163     set_flags(make_flags(field_type, option_bits | (1 << is_field_entry_shift), field_index));
 164   }
 165   void set_method_flags(TosState return_type, int option_bits, int method_params) {
 166     assert((method_params & parameter_size_mask) == method_params, "method_params in range");
 167     set_flags(make_flags(return_type, option_bits, method_params));
 168   }
 169   bool init_method_flags_atomic(TosState return_type, int option_bits, int method_params) {
 170     assert((method_params & parameter_size_mask) == method_params, "method_params in range");
 171     return init_flags_atomic(make_flags(return_type, option_bits, method_params));
 172   }
 173 
 174  public:
 175   // specific bit definitions for the flags field:
 176   // (Note: the interpreter must use these definitions to access the CP cache.)
 177   enum {
 178     // high order bits are the TosState corresponding to field type or method return type
 179     tos_state_bits             = 4,
 180     tos_state_mask             = right_n_bits(tos_state_bits),
 181     tos_state_shift            = BitsPerInt - tos_state_bits,  // see verify_tos_state_shift below
 182     // misc. option bits; can be any bit position in [16..27]
 183     is_field_entry_shift       = 26,  // (F) is it a field or a method?
 184     has_method_type_shift      = 25,  // (M) does the call site have a MethodType?
 185     has_appendix_shift         = 24,  // (A) does the call site have an appendix argument?
 186     is_forced_virtual_shift    = 23,  // (I) is the interface reference forced to virtual mode?
 187     is_final_shift             = 22,  // (f) is the field or method final?
 188     is_volatile_shift          = 21,  // (v) is the field volatile?
 189     is_vfinal_shift            = 20,  // (vf) did the call resolve to a final method?
 190     // low order bits give field index (for FieldInfo) or method parameter size:
 191     field_index_bits           = 16,
 192     field_index_mask           = right_n_bits(field_index_bits),
 193     parameter_size_bits        = 8,  // subset of field_index_mask, range is 0..255
 194     parameter_size_mask        = right_n_bits(parameter_size_bits),
 195     option_bits_mask           = ~(((-1) << tos_state_shift) | (field_index_mask | parameter_size_mask))
 196   };
 197 
 198   // specific bit definitions for the indices field:
 199   enum {
 200     cp_index_bits              = 2*BitsPerByte,
 201     cp_index_mask              = right_n_bits(cp_index_bits),
 202     bytecode_1_shift           = cp_index_bits,
 203     bytecode_1_mask            = right_n_bits(BitsPerByte), // == (u1)0xFF
 204     bytecode_2_shift           = cp_index_bits + BitsPerByte,
 205     bytecode_2_mask            = right_n_bits(BitsPerByte)  // == (u1)0xFF
 206   };
 207 
 208 
 209   // Initialization
 210   void initialize_entry(int original_index);     // initialize primary entry
 211   void initialize_resolved_reference_index(int ref_index) {
 212     assert(_f2 == 0, "set once");  // note: ref_index might be zero also
 213     _f2 = ref_index;
 214   }
 215 
 216   void set_field(                                // sets entry to resolved field state
 217     Bytecodes::Code get_code,                    // the bytecode used for reading the field
 218     Bytecodes::Code put_code,                    // the bytecode used for writing the field
 219     KlassHandle     field_holder,                // the object/klass holding the field
 220     int             orig_field_index,            // the original field index in the field holder
 221     int             field_offset,                // the field offset in words in the field holder
 222     TosState        field_type,                  // the (machine) field type
 223     bool            is_final,                     // the field is final
 224     bool            is_volatile,                 // the field is volatile
 225     Klass*          root_klass                   // needed by the GC to dirty the klass
 226   );
 227 
 228  private:
 229   void set_direct_or_vtable_call(
 230     Bytecodes::Code invoke_code,                 // the bytecode used for invoking the method
 231     methodHandle    method,                      // the method/prototype if any (NULL, otherwise)
 232     int             vtable_index                 // the vtable index if any, else negative
 233   );
 234 
 235  public:
 236   void set_direct_call(                          // sets entry to exact concrete method entry
 237     Bytecodes::Code invoke_code,                 // the bytecode used for invoking the method
 238     methodHandle    method                       // the method to call
 239   );
 240 
 241   void set_vtable_call(                          // sets entry to vtable index
 242     Bytecodes::Code invoke_code,                 // the bytecode used for invoking the method
 243     methodHandle    method,                      // resolved method which declares the vtable index
 244     int             vtable_index                 // the vtable index
 245   );
 246 
 247   void set_itable_call(
 248     Bytecodes::Code invoke_code,                 // the bytecode used; must be invokeinterface
 249     methodHandle method,                         // the resolved interface method
 250     int itable_index                             // index into itable for the method
 251   );
 252 
 253   void set_method_handle(
 254     constantPoolHandle cpool,                    // holding constant pool (required for locking)
 255     const CallInfo &call_info                    // Call link information
 256   );
 257 
 258   void set_dynamic_call(
 259     constantPoolHandle cpool,                    // holding constant pool (required for locking)
 260     const CallInfo &call_info                    // Call link information
 261   );
 262 
 263   // Common code for invokedynamic and MH invocations.
 264 
 265   // The "appendix" is an optional call-site-specific parameter which is
 266   // pushed by the JVM at the end of the argument list.  This argument may
 267   // be a MethodType for the MH.invokes and a CallSite for an invokedynamic
 268   // instruction.  However, its exact type and use depends on the Java upcall,
 269   // which simply returns a compiled LambdaForm along with any reference
 270   // that LambdaForm needs to complete the call.  If the upcall returns a
 271   // null appendix, the argument is not passed at all.
 272   //
 273   // The appendix is *not* represented in the signature of the symbolic
 274   // reference for the call site, but (if present) it *is* represented in
 275   // the Method* bound to the site.  This means that static and dynamic
 276   // resolution logic needs to make slightly different assessments about the
 277   // number and types of arguments.
 278   void set_method_handle_common(
 279     constantPoolHandle cpool,                    // holding constant pool (required for locking)
 280     Bytecodes::Code invoke_code,                 // _invokehandle or _invokedynamic
 281     const CallInfo &call_info                    // Call link information
 282   );
 283 
 284   // invokedynamic and invokehandle call sites have two entries in the
 285   // resolved references array:
 286   //   appendix   (at index+0)
 287   //   MethodType (at index+1)
 288   enum {
 289     _indy_resolved_references_appendix_offset    = 0,
 290     _indy_resolved_references_method_type_offset = 1,
 291     _indy_resolved_references_entries
 292   };
 293 
 294   Method*      method_if_resolved(constantPoolHandle cpool);
 295   oop        appendix_if_resolved(constantPoolHandle cpool);
 296   oop     method_type_if_resolved(constantPoolHandle cpool);
 297 
 298   void set_parameter_size(int value);
 299 
 300   // Which bytecode number (1 or 2) in the index field is valid for this bytecode?
 301   // Returns -1 if neither is valid.
 302   static int bytecode_number(Bytecodes::Code code) {
 303     switch (code) {
 304       case Bytecodes::_getstatic       :    // fall through
 305       case Bytecodes::_getfield        :    // fall through
 306       case Bytecodes::_invokespecial   :    // fall through
 307       case Bytecodes::_invokestatic    :    // fall through
 308       case Bytecodes::_invokehandle    :    // fall through
 309       case Bytecodes::_invokedynamic   :    // fall through
 310       case Bytecodes::_invokeinterface : return 1;
 311       case Bytecodes::_putstatic       :    // fall through
 312       case Bytecodes::_putfield        :    // fall through
 313       case Bytecodes::_invokevirtual   : return 2;
 314       default                          : break;
 315     }
 316     return -1;
 317   }
 318 
 319   // Has this bytecode been resolved? Only valid for invokes and get/put field/static.
 320   bool is_resolved(Bytecodes::Code code) const {
 321     switch (bytecode_number(code)) {
 322       case 1:  return (bytecode_1() == code);
 323       case 2:  return (bytecode_2() == code);
 324     }
 325     return false;      // default: not resolved
 326   }
 327 
 328   // Accessors
 329   int indices() const                            { return _indices; }
 330   int indices_ord() const                        { return (intx)OrderAccess::load_ptr_acquire(&_indices); }
 331   int constant_pool_index() const                { return (indices() & cp_index_mask); }
 332   Bytecodes::Code bytecode_1() const             { return Bytecodes::cast((indices_ord() >> bytecode_1_shift) & bytecode_1_mask); }
 333   Bytecodes::Code bytecode_2() const             { return Bytecodes::cast((indices_ord() >> bytecode_2_shift) & bytecode_2_mask); }
 334   Metadata* f1_ord() const                       { return (Metadata *)OrderAccess::load_ptr_acquire(&_f1); }
 335   Method*   f1_as_method() const                 { Metadata* f1 = f1_ord(); assert(f1 == NULL || f1->is_method(), ""); return (Method*)f1; }
 336   Klass*    f1_as_klass() const                  { Metadata* f1 = f1_ord(); assert(f1 == NULL || f1->is_klass(), ""); return (Klass*)f1; }
 337   // Use the accessor f1() to acquire _f1's value. This is needed for
 338   // example in BytecodeInterpreter::run(), where is_f1_null() is
 339   // called to check if an invokedynamic call is resolved. This load
 340   // of _f1 must be ordered with the loads performed by
 341   // cache->main_entry_index().
 342   bool      is_f1_null() const                   { Metadata* f1 = f1_ord(); return f1 == NULL; }  // classifies a CPC entry as unbound
 343   int       f2_as_index() const                  { assert(!is_vfinal(), ""); return (int) _f2; }
 344   Method*   f2_as_vfinal_method() const          { assert(is_vfinal(), ""); return (Method*)_f2; }
 345   int  field_index() const                       { assert(is_field_entry(),  ""); return (_flags & field_index_mask); }
 346   int  parameter_size() const                    { assert(is_method_entry(), ""); return (_flags & parameter_size_mask); }
 347   bool is_volatile() const                       { return (_flags & (1 << is_volatile_shift))       != 0; }
 348   bool is_final() const                          { return (_flags & (1 << is_final_shift))          != 0; }
 349   bool is_forced_virtual() const                 { return (_flags & (1 << is_forced_virtual_shift)) != 0; }
 350   bool is_vfinal() const                         { return (_flags & (1 << is_vfinal_shift))         != 0; }
 351   bool has_appendix() const                      { return (!is_f1_null()) && (_flags & (1 << has_appendix_shift))      != 0; }
 352   bool has_method_type() const                   { return (!is_f1_null()) && (_flags & (1 << has_method_type_shift))   != 0; }
 353   bool is_method_entry() const                   { return (_flags & (1 << is_field_entry_shift))    == 0; }
 354   bool is_field_entry() const                    { return (_flags & (1 << is_field_entry_shift))    != 0; }
 355   bool is_byte() const                           { return flag_state() == btos; }
 356   bool is_char() const                           { return flag_state() == ctos; }
 357   bool is_short() const                          { return flag_state() == stos; }
 358   bool is_int() const                            { return flag_state() == itos; }
 359   bool is_long() const                           { return flag_state() == ltos; }
 360   bool is_float() const                          { return flag_state() == ftos; }
 361   bool is_double() const                         { return flag_state() == dtos; }
 362   bool is_object() const                         { return flag_state() == atos; }
 363   TosState flag_state() const                    { assert((uint)number_of_states <= (uint)tos_state_mask+1, "");
 364                                                    return (TosState)((_flags >> tos_state_shift) & tos_state_mask); }
 365 
 366   // Code generation support
 367   static WordSize size()                         { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); }
 368   static ByteSize size_in_bytes()                { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); }
 369   static ByteSize indices_offset()               { return byte_offset_of(ConstantPoolCacheEntry, _indices); }
 370   static ByteSize f1_offset()                    { return byte_offset_of(ConstantPoolCacheEntry, _f1); }
 371   static ByteSize f2_offset()                    { return byte_offset_of(ConstantPoolCacheEntry, _f2); }
 372   static ByteSize flags_offset()                 { return byte_offset_of(ConstantPoolCacheEntry, _flags); }
 373 
 374 #if INCLUDE_JVMTI
 375   // RedefineClasses() API support:
 376   // If this ConstantPoolCacheEntry refers to old_method then update it
 377   // to refer to new_method.
 378   // trace_name_printed is set to true if the current call has
 379   // printed the klass name so that other routines in the adjust_*
 380   // group don't print the klass name.
 381   bool adjust_method_entry(Method* old_method, Method* new_method,
 382          bool * trace_name_printed);
 383   bool check_no_old_or_obsolete_entries();
 384   Method* get_interesting_method_entry(Klass* k);
 385 #endif // INCLUDE_JVMTI
 386 
 387   // Debugging & Printing
 388   void print (outputStream* st, int index) const;
 389   void verify(outputStream* st) const;
 390 
 391   static void verify_tos_state_shift() {
 392     // When shifting flags as a 32-bit int, make sure we don't need an extra mask for tos_state:
 393     assert((((u4)-1 >> tos_state_shift) & ~tos_state_mask) == 0, "no need for tos_state mask");
 394   }
 395 };
 396 
 397 
 398 // A constant pool cache is a runtime data structure set aside to a constant pool. The cache
 399 // holds interpreter runtime information for all field access and invoke bytecodes. The cache
 400 // is created and initialized before a class is actively used (i.e., initialized), the indivi-
 401 // dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*).
 402 
 403 class ConstantPoolCache: public MetaspaceObj {
 404   friend class VMStructs;
 405   friend class MetadataFactory;
 406  private:
 407   int             _length;
 408   ConstantPool*   _constant_pool;          // the corresponding constant pool
 409 
 410   // Sizing
 411   debug_only(friend class ClassVerifier;)
 412 
 413   // Constructor
 414   ConstantPoolCache(int length,
 415                     const intStack& inverse_index_map,
 416                     const intStack& invokedynamic_inverse_index_map,
 417                     const intStack& invokedynamic_references_map) :
 418                           _length(length),
 419                           _constant_pool(NULL) {
 420     initialize(inverse_index_map, invokedynamic_inverse_index_map,
 421                invokedynamic_references_map);
 422     for (int i = 0; i < length; i++) {
 423       assert(entry_at(i)->is_f1_null(), "Failed to clear?");
 424     }
 425   }
 426 
 427   // Initialization
 428   void initialize(const intArray& inverse_index_map,
 429                   const intArray& invokedynamic_inverse_index_map,
 430                   const intArray& invokedynamic_references_map);
 431  public:
 432   static ConstantPoolCache* allocate(ClassLoaderData* loader_data,
 433                                      const intStack& cp_cache_map,
 434                                      const intStack& invokedynamic_cp_cache_map,
 435                                      const intStack& invokedynamic_references_map, TRAPS);
 436   bool is_constantPoolCache() const { return true; }
 437 
 438   int length() const                             { return _length; }
 439  private:
 440   void set_length(int length)                    { _length = length; }
 441 
 442   static int header_size()                       { return sizeof(ConstantPoolCache) / HeapWordSize; }
 443   static int size(int length)                    { return align_object_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); }
 444  public:
 445   int size() const                               { return size(length()); }
 446  private:
 447 
 448   // Helpers
 449   ConstantPool**        constant_pool_addr()   { return &_constant_pool; }
 450   ConstantPoolCacheEntry* base() const           { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); }
 451 
 452   friend class constantPoolCacheKlass;
 453   friend class ConstantPoolCacheEntry;
 454 
 455  public:
 456   // Accessors
 457   void set_constant_pool(ConstantPool* pool)   { _constant_pool = pool; }
 458   ConstantPool* constant_pool() const          { return _constant_pool; }
 459   // Fetches the entry at the given index.
 460   // In either case the index must not be encoded or byte-swapped in any way.
 461   ConstantPoolCacheEntry* entry_at(int i) const {
 462     assert(0 <= i && i < length(), "index out of bounds");
 463     return base() + i;
 464   }
 465 
 466   // Code generation
 467   static ByteSize base_offset()                  { return in_ByteSize(sizeof(ConstantPoolCache)); }
 468   static ByteSize entry_offset(int raw_index) {
 469     int index = raw_index;
 470     return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index);
 471   }
 472 
 473 #if INCLUDE_JVMTI
 474   // RedefineClasses() API support:
 475   // If any entry of this ConstantPoolCache points to any of
 476   // old_methods, replace it with the corresponding new_method.
 477   // trace_name_printed is set to true if the current call has
 478   // printed the klass name so that other routines in the adjust_*
 479   // group don't print the klass name.
 480   void adjust_method_entries(Method** old_methods, Method** new_methods,
 481                              int methods_length, bool * trace_name_printed);
 482   void adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed);
 483   bool check_no_old_or_obsolete_entries();
 484   void dump_cache();
 485 #endif // INCLUDE_JVMTI
 486 
 487   // Deallocate - no fields to deallocate
 488   DEBUG_ONLY(bool on_stack() { return false; })
 489   void deallocate_contents(ClassLoaderData* data) {}
 490   bool is_klass() const { return false; }
 491 
 492   // Printing
 493   void print_on(outputStream* st) const;
 494   void print_value_on(outputStream* st) const;
 495 
 496   const char* internal_name() const { return "{constant pool cache}"; }
 497 
 498   // Verify
 499   void verify_on(outputStream* st);
 500 };
 501 
 502 #endif // SHARE_VM_OOPS_CPCACHEOOP_HPP