1 /*
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  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
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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 "oops/arrayOop.hpp"
  31 #include "utilities/array.hpp"
  32 
  33 // A ConstantPoolCacheEntry describes an individual entry of the constant
  34 // pool cache. There's 2 principal kinds of entries: field entries for in-
  35 // stance & static field access, and method entries for invokes. Some of
  36 // the entry layout is shared and looks as follows:
  37 //
  38 // bit number |31                0|
  39 // bit length |-8--|-8--|---16----|
  40 // --------------------------------
  41 // _indices   [ b2 | b1 |  index  ]
  42 // _f1        [  entry specific   ]
  43 // _f2        [  entry specific   ]
  44 // _flags     [t|f|vf|v|m|h|unused|field_index] (for field entries)
  45 // bit length |4|1|1 |1|1|0|---7--|----16-----]
  46 // _flags     [t|f|vf|v|m|h|unused|eidx|psze] (for method entries)
  47 // bit length |4|1|1 |1|1|1|---7--|-8--|-8--]
  48 
  49 // --------------------------------
  50 //
  51 // with:
  52 // index  = original constant pool index
  53 // b1     = bytecode 1
  54 // b2     = bytecode 2
  55 // psze   = parameters size (method entries only)
  56 // eidx   = interpreter entry index (method entries only)
  57 // field_index = index into field information in holder instanceKlass
  58 //          The index max is 0xffff (max number of fields in constant pool)
  59 //          and is multiplied by (instanceKlass::next_offset) when accessing.
  60 // t      = TosState (see below)
  61 // f      = field is marked final (see below)
  62 // vf     = virtual, final (method entries only : is_vfinal())
  63 // v      = field is volatile (see below)
  64 // m      = invokeinterface used for method in class Object (see below)
  65 // h      = RedefineClasses/Hotswap bit (see below)
  66 //
  67 // The flags after TosState have the following interpretation:
  68 // bit 27: f flag  true if field is marked final
  69 // bit 26: vf flag true if virtual final method
  70 // bit 25: v flag true if field is volatile (only for fields)
  71 // bit 24: m flag true if invokeinterface used for method in class Object
  72 // bit 23: 0 for fields, 1 for methods
  73 //
  74 // The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the
  75 // following mapping to the TosState states:
  76 //
  77 // btos: 0
  78 // ctos: 1
  79 // stos: 2
  80 // itos: 3
  81 // ltos: 4
  82 // ftos: 5
  83 // dtos: 6
  84 // atos: 7
  85 // vtos: 8
  86 //
  87 // Entry specific: field entries:
  88 // _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index
  89 // _f1      = field holder
  90 // _f2      = field offset in words
  91 // _flags   = field type information, original field index in field holder
  92 //            (field_index section)
  93 //
  94 // Entry specific: method entries:
  95 // _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section),
  96 //            original constant pool index
  97 // _f1      = method for all but virtual calls, unused by virtual calls
  98 //            (note: for interface calls, which are essentially virtual,
  99 //             contains klassOop for the corresponding interface.
 100 //            for invokedynamic, f1 contains the CallSite object for the invocation
 101 // _f2      = method/vtable index for virtual calls only, unused by all other
 102 //            calls.  The vf flag indicates this is a method pointer not an
 103 //            index.
 104 // _flags   = field type info (f section),
 105 //            virtual final entry (vf),
 106 //            interpreter entry index (eidx section),
 107 //            parameter size (psze section)
 108 //
 109 // Note: invokevirtual & invokespecial bytecodes can share the same constant
 110 //       pool entry and thus the same constant pool cache entry. All invoke
 111 //       bytecodes but invokevirtual use only _f1 and the corresponding b1
 112 //       bytecode, while invokevirtual uses only _f2 and the corresponding
 113 //       b2 bytecode.  The value of _flags is shared for both types of entries.
 114 //
 115 // The fields are volatile so that they are stored in the order written in the
 116 // source code.  The _indices field with the bytecode must be written last.
 117 
 118 class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC {
 119   friend class VMStructs;
 120   friend class constantPoolCacheKlass;
 121   friend class constantPoolOopDesc;  //resolve_constant_at_impl => set_f1
 122 
 123  private:
 124   volatile intx     _indices;  // constant pool index & rewrite bytecodes
 125   volatile oop      _f1;       // entry specific oop field
 126   volatile intx     _f2;       // entry specific int/oop field
 127   volatile intx     _flags;    // flags
 128 
 129 
 130 #ifdef ASSERT
 131   bool same_methodOop(oop cur_f1, oop f1);
 132 #endif
 133 
 134   void set_bytecode_1(Bytecodes::Code code);
 135   void set_bytecode_2(Bytecodes::Code code);
 136   void set_f1(oop f1)                            {
 137     oop existing_f1 = _f1; // read once
 138     assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change");
 139     oop_store(&_f1, f1);
 140   }
 141   void set_f1_if_null_atomic(oop f1);
 142   void set_f2(intx f2)                           { assert(_f2 == 0    || _f2 == f2, "illegal field change"); _f2 = f2; }
 143   int as_flags(TosState state, bool is_final, bool is_vfinal, bool is_volatile,
 144                bool is_method_interface, bool is_method);
 145   void set_flags(intx flags)                     { _flags = flags; }
 146 
 147  public:
 148   // specific bit values in flag field
 149   // Note: the interpreter knows this layout!
 150   enum FlagBitValues {
 151     hotSwapBit    = 23,
 152     methodInterface = 24,
 153     volatileField = 25,
 154     vfinalMethod  = 26,
 155     finalField    = 27
 156   };
 157 
 158   enum { field_index_mask = 0xFFFF };
 159 
 160   // start of type bits in flags
 161   // Note: the interpreter knows this layout!
 162   enum FlagValues {
 163     tosBits      = 28
 164   };
 165 
 166   // Initialization
 167   void initialize_entry(int original_index);     // initialize primary entry
 168   void initialize_secondary_entry(int main_index); // initialize secondary entry
 169 
 170   void set_field(                                // sets entry to resolved field state
 171     Bytecodes::Code get_code,                    // the bytecode used for reading the field
 172     Bytecodes::Code put_code,                    // the bytecode used for writing the field
 173     KlassHandle     field_holder,                // the object/klass holding the field
 174     int             orig_field_index,            // the original field index in the field holder
 175     int             field_offset,                // the field offset in words in the field holder
 176     TosState        field_type,                  // the (machine) field type
 177     bool            is_final,                     // the field is final
 178     bool            is_volatile                  // the field is volatile
 179   );
 180 
 181   void set_method(                               // sets entry to resolved method entry
 182     Bytecodes::Code invoke_code,                 // the bytecode used for invoking the method
 183     methodHandle    method,                      // the method/prototype if any (NULL, otherwise)
 184     int             vtable_index                 // the vtable index if any, else negative
 185   );
 186 
 187   void set_interface_call(
 188     methodHandle method,                         // Resolved method
 189     int index                                    // Method index into interface
 190   );
 191 
 192   void set_dynamic_call(
 193     Handle call_site,                            // Resolved java.lang.invoke.CallSite (f1)
 194     methodHandle signature_invoker               // determines signature information
 195   );
 196 
 197   methodOop get_method_if_resolved(Bytecodes::Code invoke_code, constantPoolHandle cpool);
 198 
 199   // For JVM_CONSTANT_InvokeDynamic cache entries:
 200   void initialize_bootstrap_method_index_in_cache(int bsm_cache_index);
 201   int  bootstrap_method_index_in_cache();
 202 
 203   void set_parameter_size(int value) {
 204     assert(parameter_size() == 0 || parameter_size() == value,
 205            "size must not change");
 206     // Setting the parameter size by itself is only safe if the
 207     // current value of _flags is 0, otherwise another thread may have
 208     // updated it and we don't want to overwrite that value.  Don't
 209     // bother trying to update it once it's nonzero but always make
 210     // sure that the final parameter size agrees with what was passed.
 211     if (_flags == 0) {
 212       Atomic::cmpxchg_ptr((value & 0xFF), &_flags, 0);
 213     }
 214     guarantee(parameter_size() == value, "size must not change");
 215   }
 216 
 217   // Which bytecode number (1 or 2) in the index field is valid for this bytecode?
 218   // Returns -1 if neither is valid.
 219   static int bytecode_number(Bytecodes::Code code) {
 220     switch (code) {
 221       case Bytecodes::_getstatic       :    // fall through
 222       case Bytecodes::_getfield        :    // fall through
 223       case Bytecodes::_invokespecial   :    // fall through
 224       case Bytecodes::_invokestatic    :    // fall through
 225       case Bytecodes::_invokedynamic   :    // fall through
 226       case Bytecodes::_invokeinterface : return 1;
 227       case Bytecodes::_putstatic       :    // fall through
 228       case Bytecodes::_putfield        :    // fall through
 229       case Bytecodes::_invokevirtual   : return 2;
 230       default                          : break;
 231     }
 232     return -1;
 233   }
 234 
 235   // Has this bytecode been resolved? Only valid for invokes and get/put field/static.
 236   bool is_resolved(Bytecodes::Code code) const {
 237     switch (bytecode_number(code)) {
 238       case 1:  return (bytecode_1() == code);
 239       case 2:  return (bytecode_2() == code);
 240     }
 241     return false;      // default: not resolved
 242   }
 243 
 244   // Accessors
 245   bool is_secondary_entry() const                { return (_indices & 0xFFFF) == 0; }
 246   int constant_pool_index() const                { assert((_indices & 0xFFFF) != 0, "must be main entry");
 247                                                    return (_indices & 0xFFFF); }
 248   int main_entry_index() const                   { assert((_indices & 0xFFFF) == 0, "must be secondary entry");
 249                                                    return ((uintx)_indices >> 16); }
 250   Bytecodes::Code bytecode_1() const             { return Bytecodes::cast((_indices >> 16) & 0xFF); }
 251   Bytecodes::Code bytecode_2() const             { return Bytecodes::cast((_indices >> 24) & 0xFF); }
 252   volatile oop  f1() const                       { return _f1; }
 253   bool is_f1_null() const                        { return (oop)_f1 == NULL; }  // classifies a CPC entry as unbound
 254   intx f2() const                                { return _f2; }
 255   int  field_index() const;
 256   int  parameter_size() const                    { return _flags & 0xFF; }
 257   bool is_vfinal() const                         { return ((_flags & (1 << vfinalMethod)) == (1 << vfinalMethod)); }
 258   bool is_volatile() const                       { return ((_flags & (1 << volatileField)) == (1 << volatileField)); }
 259   bool is_methodInterface() const                { return ((_flags & (1 << methodInterface)) == (1 << methodInterface)); }
 260   bool is_byte() const                           { return (((uintx) _flags >> tosBits) == btos); }
 261   bool is_char() const                           { return (((uintx) _flags >> tosBits) == ctos); }
 262   bool is_short() const                          { return (((uintx) _flags >> tosBits) == stos); }
 263   bool is_int() const                            { return (((uintx) _flags >> tosBits) == itos); }
 264   bool is_long() const                           { return (((uintx) _flags >> tosBits) == ltos); }
 265   bool is_float() const                          { return (((uintx) _flags >> tosBits) == ftos); }
 266   bool is_double() const                         { return (((uintx) _flags >> tosBits) == dtos); }
 267   bool is_object() const                         { return (((uintx) _flags >> tosBits) == atos); }
 268   TosState flag_state() const                    { assert( ( (_flags >> tosBits) & 0x0F ) < number_of_states, "Invalid state in as_flags");
 269                                                    return (TosState)((_flags >> tosBits) & 0x0F); }
 270 
 271   // Code generation support
 272   static WordSize size()                         { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); }
 273   static ByteSize size_in_bytes()                { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); }
 274   static ByteSize indices_offset()               { return byte_offset_of(ConstantPoolCacheEntry, _indices); }
 275   static ByteSize f1_offset()                    { return byte_offset_of(ConstantPoolCacheEntry, _f1); }
 276   static ByteSize f2_offset()                    { return byte_offset_of(ConstantPoolCacheEntry, _f2); }
 277   static ByteSize flags_offset()                 { return byte_offset_of(ConstantPoolCacheEntry, _flags); }
 278 
 279   // GC Support
 280   void oops_do(void f(oop*));
 281   void oop_iterate(OopClosure* blk);
 282   void oop_iterate_m(OopClosure* blk, MemRegion mr);
 283   void follow_contents();
 284   void adjust_pointers();
 285 
 286 #ifndef SERIALGC
 287   // Parallel Old
 288   void follow_contents(ParCompactionManager* cm);
 289 #endif // SERIALGC
 290 
 291   void update_pointers();
 292 
 293   // RedefineClasses() API support:
 294   // If this constantPoolCacheEntry refers to old_method then update it
 295   // to refer to new_method.
 296   // trace_name_printed is set to true if the current call has
 297   // printed the klass name so that other routines in the adjust_*
 298   // group don't print the klass name.
 299   bool adjust_method_entry(methodOop old_method, methodOop new_method,
 300          bool * trace_name_printed);
 301   bool check_no_old_or_obsolete_entries();
 302   bool is_interesting_method_entry(klassOop k);
 303   bool is_field_entry() const                    { return (_flags & (1 << hotSwapBit)) == 0; }
 304   bool is_method_entry() const                   { return (_flags & (1 << hotSwapBit)) != 0; }
 305 
 306   // Debugging & Printing
 307   void print (outputStream* st, int index) const;
 308   void verify(outputStream* st) const;
 309 
 310   static void verify_tosBits() {
 311     assert(tosBits == 28, "interpreter now assumes tosBits is 28");
 312   }
 313 };
 314 
 315 
 316 // A constant pool cache is a runtime data structure set aside to a constant pool. The cache
 317 // holds interpreter runtime information for all field access and invoke bytecodes. The cache
 318 // is created and initialized before a class is actively used (i.e., initialized), the indivi-
 319 // dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*).
 320 
 321 class constantPoolCacheOopDesc: public oopDesc {
 322   friend class VMStructs;
 323  private:
 324   int             _length;
 325   constantPoolOop _constant_pool;                // the corresponding constant pool
 326 
 327   // Sizing
 328   debug_only(friend class ClassVerifier;)
 329  public:
 330   int length() const                             { return _length; }
 331  private:
 332   void set_length(int length)                    { _length = length; }
 333 
 334   static int header_size()                       { return sizeof(constantPoolCacheOopDesc) / HeapWordSize; }
 335   static int object_size(int length)             { return align_object_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); }
 336   int object_size()                              { return object_size(length()); }
 337 
 338   // Helpers
 339   constantPoolOop*        constant_pool_addr()   { return &_constant_pool; }
 340   ConstantPoolCacheEntry* base() const           { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); }
 341 
 342   friend class constantPoolCacheKlass;
 343   friend class ConstantPoolCacheEntry;
 344 
 345  public:
 346   // Initialization
 347   void initialize(intArray& inverse_index_map);
 348 
 349   // Secondary indexes.
 350   // They must look completely different from normal indexes.
 351   // The main reason is that byte swapping is sometimes done on normal indexes.
 352   // Also, some of the CP accessors do different things for secondary indexes.
 353   // Finally, it is helpful for debugging to tell the two apart.
 354   static bool is_secondary_index(int i) { return (i < 0); }
 355   static int  decode_secondary_index(int i) { assert(is_secondary_index(i),  ""); return ~i; }
 356   static int  encode_secondary_index(int i) { assert(!is_secondary_index(i), ""); return ~i; }
 357 
 358   // Accessors
 359   void set_constant_pool(constantPoolOop pool)   { oop_store_without_check((oop*)&_constant_pool, (oop)pool); }
 360   constantPoolOop constant_pool() const          { return _constant_pool; }
 361   // Fetches the entry at the given index.
 362   // The entry may be either primary or secondary.
 363   // In either case the index must not be encoded or byte-swapped in any way.
 364   ConstantPoolCacheEntry* entry_at(int i) const {
 365     assert(0 <= i && i < length(), "index out of bounds");
 366     return base() + i;
 367   }
 368   // Fetches the secondary entry referred to by index.
 369   // The index may be a secondary index, and must not be byte-swapped.
 370   ConstantPoolCacheEntry* secondary_entry_at(int i) const {
 371     int raw_index = i;
 372     if (is_secondary_index(i)) {  // correct these on the fly
 373       raw_index = decode_secondary_index(i);
 374     }
 375     assert(entry_at(raw_index)->is_secondary_entry(), "not a secondary entry");
 376     return entry_at(raw_index);
 377   }
 378   // Given a primary or secondary index, fetch the corresponding primary entry.
 379   // Indirect through the secondary entry, if the index is encoded as a secondary index.
 380   // The index must not be byte-swapped.
 381   ConstantPoolCacheEntry* main_entry_at(int i) const {
 382     int primary_index = i;
 383     if (is_secondary_index(i)) {
 384       // run through an extra level of indirection:
 385       int raw_index = decode_secondary_index(i);
 386       primary_index = entry_at(raw_index)->main_entry_index();
 387     }
 388     assert(!entry_at(primary_index)->is_secondary_entry(), "only one level of indirection");
 389     return entry_at(primary_index);
 390   }
 391 
 392   // Code generation
 393   static ByteSize base_offset()                  { return in_ByteSize(sizeof(constantPoolCacheOopDesc)); }
 394   static ByteSize entry_offset(int raw_index) {
 395     int index = raw_index;
 396     if (is_secondary_index(raw_index))
 397       index = decode_secondary_index(raw_index);
 398     return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index);
 399   }
 400 
 401   // RedefineClasses() API support:
 402   // If any entry of this constantPoolCache points to any of
 403   // old_methods, replace it with the corresponding new_method.
 404   // trace_name_printed is set to true if the current call has
 405   // printed the klass name so that other routines in the adjust_*
 406   // group don't print the klass name.
 407   void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
 408                              int methods_length, bool * trace_name_printed);
 409   bool check_no_old_or_obsolete_entries();
 410   void dump_cache();
 411 };
 412 
 413 #endif // SHARE_VM_OOPS_CPCACHEOOP_HPP