1 /*
   2  * Copyright (c) 1997, 2018, 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
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  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.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP
  26 #define SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP
  27 
  28 #include "oops/arrayOop.hpp"
  29 #include "oops/cpCache.hpp"
  30 #include "oops/objArrayOop.hpp"
  31 #include "oops/symbol.hpp"
  32 #include "oops/typeArrayOop.hpp"
  33 #include "runtime/handles.hpp"
  34 #include "utilities/constantTag.hpp"
  35 #ifdef TARGET_ARCH_x86
  36 # include "bytes_x86.hpp"
  37 #endif
  38 #ifdef TARGET_ARCH_sparc
  39 # include "bytes_sparc.hpp"
  40 #endif
  41 #ifdef TARGET_ARCH_zero
  42 # include "bytes_zero.hpp"
  43 #endif
  44 #ifdef TARGET_ARCH_arm
  45 # include "bytes_arm.hpp"
  46 #endif
  47 #ifdef TARGET_ARCH_ppc
  48 # include "bytes_ppc.hpp"
  49 #endif
  50 
  51 // A constantPool is an array containing class constants as described in the
  52 // class file.
  53 //
  54 // Most of the constant pool entries are written during class parsing, which
  55 // is safe.  For klass types, the constant pool entry is
  56 // modified when the entry is resolved.  If a klass constant pool
  57 // entry is read without a lock, only the resolved state guarantees that
  58 // the entry in the constant pool is a klass object and not a Symbol*.
  59 
  60 class SymbolHashMap;
  61 
  62 class CPSlot VALUE_OBJ_CLASS_SPEC {
  63   intptr_t _ptr;
  64  public:
  65   CPSlot(intptr_t ptr): _ptr(ptr) {}
  66   CPSlot(Klass* ptr): _ptr((intptr_t)ptr) {}
  67   CPSlot(Symbol* ptr): _ptr((intptr_t)ptr | 1) {}
  68 
  69   intptr_t value()   { return _ptr; }
  70   bool is_resolved()   { return (_ptr & 1) == 0; }
  71   bool is_unresolved() { return (_ptr & 1) == 1; }
  72 
  73   Symbol* get_symbol() {
  74     assert(is_unresolved(), "bad call");
  75     return (Symbol*)(_ptr & ~1);
  76   }
  77   Klass* get_klass() {
  78     assert(is_resolved(), "bad call");
  79     return (Klass*)_ptr;
  80   }
  81 };
  82 
  83 class KlassSizeStats;
  84 class ConstantPool : public Metadata {
  85   friend class VMStructs;
  86   friend class BytecodeInterpreter;  // Directly extracts an oop in the pool for fast instanceof/checkcast
  87   friend class Universe;             // For null constructor
  88  private:
  89   Array<u1>*           _tags;        // the tag array describing the constant pool's contents
  90   ConstantPoolCache*   _cache;       // the cache holding interpreter runtime information
  91   InstanceKlass*       _pool_holder; // the corresponding class
  92   Array<u2>*           _operands;    // for variable-sized (InvokeDynamic) nodes, usually empty
  93 
  94   // Array of resolved objects from the constant pool and map from resolved
  95   // object index to original constant pool index
  96   jobject              _resolved_references;
  97   Array<u2>*           _reference_map;
  98 
  99   enum {
 100     _has_preresolution = 1,           // Flags
 101     _on_stack          = 2
 102   };
 103 
 104   int                  _flags;  // old fashioned bit twiddling
 105   int                  _length; // number of elements in the array
 106 
 107   union {
 108     // set for CDS to restore resolved references
 109     int                _resolved_reference_length;
 110     // keeps version number for redefined classes (used in backtrace)
 111     int                _version;
 112   } _saved;
 113 
 114   Monitor*             _lock;
 115 
 116   void set_tags(Array<u1>* tags)               { _tags = tags; }
 117   void tag_at_put(int which, jbyte t)          { tags()->at_put(which, t); }
 118   void release_tag_at_put(int which, jbyte t)  { tags()->release_at_put(which, t); }
 119 
 120   void set_operands(Array<u2>* operands)       { _operands = operands; }
 121 
 122   int flags() const                            { return _flags; }
 123   void set_flags(int f)                        { _flags = f; }
 124 
 125  private:
 126   intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); }
 127 
 128   CPSlot slot_at(int which) {
 129     assert(is_within_bounds(which), "index out of bounds");
 130     // Uses volatile because the klass slot changes without a lock.
 131     volatile intptr_t adr = (intptr_t)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which));
 132     assert(adr != 0 || which == 0, "cp entry for klass should not be zero");
 133     return CPSlot(adr);
 134   }
 135 
 136   void slot_at_put(int which, CPSlot s) const {
 137     assert(is_within_bounds(which), "index out of bounds");
 138     assert(s.value() != 0, "Caught something");
 139     *(intptr_t*)&base()[which] = s.value();
 140   }
 141   intptr_t* obj_at_addr_raw(int which) const {
 142     assert(is_within_bounds(which), "index out of bounds");
 143     return (intptr_t*) &base()[which];
 144   }
 145 
 146   jint* int_at_addr(int which) const {
 147     assert(is_within_bounds(which), "index out of bounds");
 148     return (jint*) &base()[which];
 149   }
 150 
 151   jlong* long_at_addr(int which) const {
 152     assert(is_within_bounds(which), "index out of bounds");
 153     return (jlong*) &base()[which];
 154   }
 155 
 156   jfloat* float_at_addr(int which) const {
 157     assert(is_within_bounds(which), "index out of bounds");
 158     return (jfloat*) &base()[which];
 159   }
 160 
 161   jdouble* double_at_addr(int which) const {
 162     assert(is_within_bounds(which), "index out of bounds");
 163     return (jdouble*) &base()[which];
 164   }
 165 
 166   ConstantPool(Array<u1>* tags);
 167   ConstantPool() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
 168  public:
 169   static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS);
 170 
 171   bool is_constantPool() const volatile     { return true; }
 172 
 173   Array<u1>* tags() const                   { return _tags; }
 174   Array<u2>* operands() const               { return _operands; }
 175 
 176   bool has_preresolution() const            { return (_flags & _has_preresolution) != 0; }
 177   void set_has_preresolution()              { _flags |= _has_preresolution; }
 178 
 179   // Redefine classes support.  If a method refering to this constant pool
 180   // is on the executing stack, or as a handle in vm code, this constant pool
 181   // can't be removed from the set of previous versions saved in the instance
 182   // class.
 183   bool on_stack() const                      { return (_flags &_on_stack) != 0; }
 184   void set_on_stack(const bool value);
 185 
 186   // Klass holding pool
 187   InstanceKlass* pool_holder() const      { return _pool_holder; }
 188   void set_pool_holder(InstanceKlass* k)  { _pool_holder = k; }
 189   InstanceKlass** pool_holder_addr()      { return &_pool_holder; }
 190 
 191   // Interpreter runtime support
 192   ConstantPoolCache* cache() const        { return _cache; }
 193   void set_cache(ConstantPoolCache* cache){ _cache = cache; }
 194 
 195   // Create object cache in the constant pool
 196   void initialize_resolved_references(ClassLoaderData* loader_data,
 197                                       intStack reference_map,
 198                                       int constant_pool_map_length,
 199                                       TRAPS);
 200 
 201   // resolved strings, methodHandles and callsite objects from the constant pool
 202   objArrayOop resolved_references()  const;
 203   objArrayOop resolved_references_or_null()  const;
 204   // mapping resolved object array indexes to cp indexes and back.
 205   int object_to_cp_index(int index)         { return _reference_map->at(index); }
 206   int cp_to_object_index(int index);
 207 
 208   // Invokedynamic indexes.
 209   // They must look completely different from normal indexes.
 210   // The main reason is that byte swapping is sometimes done on normal indexes.
 211   // Finally, it is helpful for debugging to tell the two apart.
 212   static bool is_invokedynamic_index(int i) { return (i < 0); }
 213   static int  decode_invokedynamic_index(int i) { assert(is_invokedynamic_index(i),  ""); return ~i; }
 214   static int  encode_invokedynamic_index(int i) { assert(!is_invokedynamic_index(i), ""); return ~i; }
 215 
 216 
 217   // The invokedynamic points at a CP cache entry.  This entry points back
 218   // at the original CP entry (CONSTANT_InvokeDynamic) and also (via f2) at an entry
 219   // in the resolved_references array (which provides the appendix argument).
 220   int invokedynamic_cp_cache_index(int index) const {
 221     assert (is_invokedynamic_index(index), "should be a invokedynamic index");
 222     int cache_index = decode_invokedynamic_index(index);
 223     return cache_index;
 224   }
 225   ConstantPoolCacheEntry* invokedynamic_cp_cache_entry_at(int index) const {
 226     // decode index that invokedynamic points to.
 227     int cp_cache_index = invokedynamic_cp_cache_index(index);
 228     return cache()->entry_at(cp_cache_index);
 229   }
 230 
 231   // Assembly code support
 232   static int tags_offset_in_bytes()         { return offset_of(ConstantPool, _tags); }
 233   static int cache_offset_in_bytes()        { return offset_of(ConstantPool, _cache); }
 234   static int pool_holder_offset_in_bytes()  { return offset_of(ConstantPool, _pool_holder); }
 235   static int resolved_references_offset_in_bytes() { return offset_of(ConstantPool, _resolved_references); }
 236 
 237   // Storing constants
 238 
 239   void klass_at_put(int which, Klass* k) {
 240     assert(k != NULL, "resolved class shouldn't be null");
 241     assert(is_within_bounds(which), "index out of bounds");
 242     OrderAccess::release_store_ptr((Klass* volatile *)obj_at_addr_raw(which), k);
 243     // The interpreter assumes when the tag is stored, the klass is resolved
 244     // and the Klass* is a klass rather than a Symbol*, so we need
 245     // hardware store ordering here.
 246     release_tag_at_put(which, JVM_CONSTANT_Class);
 247   }
 248 
 249   // For temporary use while constructing constant pool
 250   void klass_index_at_put(int which, int name_index) {
 251     tag_at_put(which, JVM_CONSTANT_ClassIndex);
 252     *int_at_addr(which) = name_index;
 253   }
 254 
 255   // Temporary until actual use
 256   void unresolved_klass_at_put(int which, Symbol* s) {
 257     release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
 258     slot_at_put(which, s);
 259   }
 260 
 261   void method_handle_index_at_put(int which, int ref_kind, int ref_index) {
 262     tag_at_put(which, JVM_CONSTANT_MethodHandle);
 263     *int_at_addr(which) = ((jint) ref_index<<16) | ref_kind;
 264   }
 265 
 266   void method_type_index_at_put(int which, int ref_index) {
 267     tag_at_put(which, JVM_CONSTANT_MethodType);
 268     *int_at_addr(which) = ref_index;
 269   }
 270 
 271   void invoke_dynamic_at_put(int which, int bootstrap_specifier_index, int name_and_type_index) {
 272     tag_at_put(which, JVM_CONSTANT_InvokeDynamic);
 273     *int_at_addr(which) = ((jint) name_and_type_index<<16) | bootstrap_specifier_index;
 274   }
 275 
 276   void unresolved_string_at_put(int which, Symbol* s) {
 277     release_tag_at_put(which, JVM_CONSTANT_String);
 278     *symbol_at_addr(which) = s;
 279   }
 280 
 281   void int_at_put(int which, jint i) {
 282     tag_at_put(which, JVM_CONSTANT_Integer);
 283     *int_at_addr(which) = i;
 284   }
 285 
 286   void long_at_put(int which, jlong l) {
 287     tag_at_put(which, JVM_CONSTANT_Long);
 288     // *long_at_addr(which) = l;
 289     Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
 290   }
 291 
 292   void float_at_put(int which, jfloat f) {
 293     tag_at_put(which, JVM_CONSTANT_Float);
 294     *float_at_addr(which) = f;
 295   }
 296 
 297   void double_at_put(int which, jdouble d) {
 298     tag_at_put(which, JVM_CONSTANT_Double);
 299     // *double_at_addr(which) = d;
 300     // u8 temp = *(u8*) &d;
 301     Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
 302   }
 303 
 304   Symbol** symbol_at_addr(int which) const {
 305     assert(is_within_bounds(which), "index out of bounds");
 306     return (Symbol**) &base()[which];
 307   }
 308 
 309   void symbol_at_put(int which, Symbol* s) {
 310     assert(s->refcount() != 0, "should have nonzero refcount");
 311     tag_at_put(which, JVM_CONSTANT_Utf8);
 312     *symbol_at_addr(which) = s;
 313   }
 314 
 315   void string_at_put(int which, int obj_index, oop str) {
 316     resolved_references()->obj_at_put(obj_index, str);
 317   }
 318 
 319   // For temporary use while constructing constant pool
 320   void string_index_at_put(int which, int string_index) {
 321     tag_at_put(which, JVM_CONSTANT_StringIndex);
 322     *int_at_addr(which) = string_index;
 323   }
 324 
 325   void field_at_put(int which, int class_index, int name_and_type_index) {
 326     tag_at_put(which, JVM_CONSTANT_Fieldref);
 327     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
 328   }
 329 
 330   void method_at_put(int which, int class_index, int name_and_type_index) {
 331     tag_at_put(which, JVM_CONSTANT_Methodref);
 332     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
 333   }
 334 
 335   void interface_method_at_put(int which, int class_index, int name_and_type_index) {
 336     tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
 337     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;  // Not so nice
 338   }
 339 
 340   void name_and_type_at_put(int which, int name_index, int signature_index) {
 341     tag_at_put(which, JVM_CONSTANT_NameAndType);
 342     *int_at_addr(which) = ((jint) signature_index<<16) | name_index;  // Not so nice
 343   }
 344 
 345   // Tag query
 346 
 347   constantTag tag_at(int which) const { return (constantTag)tags()->at_acquire(which); }
 348 
 349   // Fetching constants
 350 
 351   Klass* klass_at(int which, TRAPS) {
 352     constantPoolHandle h_this(THREAD, this);
 353     return klass_at_impl(h_this, which, CHECK_NULL);
 354   }
 355 
 356   Symbol* klass_name_at(int which);  // Returns the name, w/o resolving.
 357 
 358   Klass* resolved_klass_at(int which) const {  // Used by Compiler
 359     guarantee(tag_at(which).is_klass(), "Corrupted constant pool");
 360     // Must do an acquire here in case another thread resolved the klass
 361     // behind our back, lest we later load stale values thru the oop.
 362     return CPSlot((Klass*)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which))).get_klass();
 363   }
 364 
 365   // This method should only be used with a cpool lock or during parsing or gc
 366   Symbol* unresolved_klass_at(int which) {     // Temporary until actual use
 367     Symbol* s = CPSlot((Symbol*)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which))).get_symbol();
 368     // check that the klass is still unresolved.
 369     assert(tag_at(which).is_unresolved_klass(), "Corrupted constant pool");
 370     return s;
 371   }
 372 
 373   // RedefineClasses() API support:
 374   Symbol* klass_at_noresolve(int which) { return klass_name_at(which); }
 375 
 376   jint int_at(int which) {
 377     assert(tag_at(which).is_int(), "Corrupted constant pool");
 378     return *int_at_addr(which);
 379   }
 380 
 381   jlong long_at(int which) {
 382     assert(tag_at(which).is_long(), "Corrupted constant pool");
 383     // return *long_at_addr(which);
 384     u8 tmp = Bytes::get_native_u8((address)&base()[which]);
 385     return *((jlong*)&tmp);
 386   }
 387 
 388   jfloat float_at(int which) {
 389     assert(tag_at(which).is_float(), "Corrupted constant pool");
 390     return *float_at_addr(which);
 391   }
 392 
 393   jdouble double_at(int which) {
 394     assert(tag_at(which).is_double(), "Corrupted constant pool");
 395     u8 tmp = Bytes::get_native_u8((address)&base()[which]);
 396     return *((jdouble*)&tmp);
 397   }
 398 
 399   Symbol* symbol_at(int which) {
 400     assert(tag_at(which).is_utf8(), "Corrupted constant pool");
 401     return *symbol_at_addr(which);
 402   }
 403 
 404   oop string_at(int which, int obj_index, TRAPS) {
 405     constantPoolHandle h_this(THREAD, this);
 406     return string_at_impl(h_this, which, obj_index, THREAD);
 407   }
 408   oop string_at(int which, TRAPS) {
 409     int obj_index = cp_to_object_index(which);
 410     return string_at(which, obj_index, THREAD);
 411   }
 412 
 413   // Version that can be used before string oop array is created.
 414   oop uncached_string_at(int which, TRAPS);
 415 
 416   // A "pseudo-string" is an non-string oop that has found is way into
 417   // a String entry.
 418   // Under EnableInvokeDynamic this can happen if the user patches a live
 419   // object into a CONSTANT_String entry of an anonymous class.
 420   // Method oops internally created for method handles may also
 421   // use pseudo-strings to link themselves to related metaobjects.
 422 
 423   bool is_pseudo_string_at(int which) {
 424     // A pseudo string is a string that doesn't have a symbol in the cpSlot
 425     return unresolved_string_at(which) == NULL;
 426   }
 427 
 428   oop pseudo_string_at(int which, int obj_index) {
 429     assert(tag_at(which).is_string(), "Corrupted constant pool");
 430     assert(unresolved_string_at(which) == NULL, "shouldn't have symbol");
 431     oop s = resolved_references()->obj_at(obj_index);
 432     return s;
 433   }
 434 
 435   oop pseudo_string_at(int which) {
 436     assert(tag_at(which).is_string(), "Corrupted constant pool");
 437     assert(unresolved_string_at(which) == NULL, "shouldn't have symbol");
 438     int obj_index = cp_to_object_index(which);
 439     oop s = resolved_references()->obj_at(obj_index);
 440     return s;
 441   }
 442 
 443   void pseudo_string_at_put(int which, int obj_index, oop x) {
 444     assert(EnableInvokeDynamic, "");
 445     assert(tag_at(which).is_string(), "Corrupted constant pool");
 446     unresolved_string_at_put(which, NULL); // indicates patched string
 447     string_at_put(which, obj_index, x);    // this works just fine
 448   }
 449 
 450   // only called when we are sure a string entry is already resolved (via an
 451   // earlier string_at call.
 452   oop resolved_string_at(int which) {
 453     assert(tag_at(which).is_string(), "Corrupted constant pool");
 454     // Must do an acquire here in case another thread resolved the klass
 455     // behind our back, lest we later load stale values thru the oop.
 456     // we might want a volatile_obj_at in ObjArrayKlass.
 457     int obj_index = cp_to_object_index(which);
 458     return resolved_references()->obj_at(obj_index);
 459   }
 460 
 461   Symbol* unresolved_string_at(int which) {
 462     assert(tag_at(which).is_string(), "Corrupted constant pool");
 463     Symbol* s = *symbol_at_addr(which);
 464     return s;
 465   }
 466 
 467   // Returns an UTF8 for a CONSTANT_String entry at a given index.
 468   // UTF8 char* representation was chosen to avoid conversion of
 469   // java_lang_Strings at resolved entries into Symbol*s
 470   // or vice versa.
 471   // Caller is responsible for checking for pseudo-strings.
 472   char* string_at_noresolve(int which);
 473 
 474   jint name_and_type_at(int which) {
 475     assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
 476     return *int_at_addr(which);
 477   }
 478 
 479  private:
 480   int method_handle_ref_kind_at(int which, bool error_ok) {
 481     assert(tag_at(which).is_method_handle() ||
 482            (error_ok && tag_at(which).is_method_handle_in_error()), "Corrupted constant pool");
 483     return extract_low_short_from_int(*int_at_addr(which));  // mask out unwanted ref_index bits
 484   }
 485   int method_handle_index_at(int which, bool error_ok) {
 486     assert(tag_at(which).is_method_handle() ||
 487            (error_ok && tag_at(which).is_method_handle_in_error()), "Corrupted constant pool");
 488     return extract_high_short_from_int(*int_at_addr(which));  // shift out unwanted ref_kind bits
 489   }
 490   int method_type_index_at(int which, bool error_ok) {
 491     assert(tag_at(which).is_method_type() ||
 492            (error_ok && tag_at(which).is_method_type_in_error()), "Corrupted constant pool");
 493     return *int_at_addr(which);
 494   }
 495  public:
 496   int method_handle_ref_kind_at(int which) {
 497     return method_handle_ref_kind_at(which, false);
 498   }
 499   int method_handle_ref_kind_at_error_ok(int which) {
 500     return method_handle_ref_kind_at(which, true);
 501   }
 502   int method_handle_index_at(int which) {
 503     return method_handle_index_at(which, false);
 504   }
 505   int method_handle_index_at_error_ok(int which) {
 506     return method_handle_index_at(which, true);
 507   }
 508   int method_type_index_at(int which) {
 509     return method_type_index_at(which, false);
 510   }
 511   int method_type_index_at_error_ok(int which) {
 512     return method_type_index_at(which, true);
 513   }
 514 
 515   // Derived queries:
 516   Symbol* method_handle_name_ref_at(int which) {
 517     int member = method_handle_index_at(which);
 518     return impl_name_ref_at(member, true);
 519   }
 520   Symbol* method_handle_signature_ref_at(int which) {
 521     int member = method_handle_index_at(which);
 522     return impl_signature_ref_at(member, true);
 523   }
 524   int method_handle_klass_index_at(int which) {
 525     int member = method_handle_index_at(which);
 526     return impl_klass_ref_index_at(member, true);
 527   }
 528   Symbol* method_type_signature_at(int which) {
 529     int sym = method_type_index_at(which);
 530     return symbol_at(sym);
 531   }
 532 
 533   int invoke_dynamic_name_and_type_ref_index_at(int which) {
 534     assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
 535     return extract_high_short_from_int(*int_at_addr(which));
 536   }
 537   int invoke_dynamic_bootstrap_specifier_index(int which) {
 538     assert(tag_at(which).value() == JVM_CONSTANT_InvokeDynamic, "Corrupted constant pool");
 539     return extract_low_short_from_int(*int_at_addr(which));
 540   }
 541   int invoke_dynamic_operand_base(int which) {
 542     int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
 543     return operand_offset_at(operands(), bootstrap_specifier_index);
 544   }
 545   // The first part of the operands array consists of an index into the second part.
 546   // Extract a 32-bit index value from the first part.
 547   static int operand_offset_at(Array<u2>* operands, int bootstrap_specifier_index) {
 548     int n = (bootstrap_specifier_index * 2);
 549     assert(n >= 0 && n+2 <= operands->length(), "oob");
 550     // The first 32-bit index points to the beginning of the second part
 551     // of the operands array.  Make sure this index is in the first part.
 552     DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0),
 553                                                        operands->at(1)));
 554     assert(second_part == 0 || n+2 <= second_part, "oob (2)");
 555     int offset = build_int_from_shorts(operands->at(n+0),
 556                                        operands->at(n+1));
 557     // The offset itself must point into the second part of the array.
 558     assert(offset == 0 || offset >= second_part && offset <= operands->length(), "oob (3)");
 559     return offset;
 560   }
 561   static void operand_offset_at_put(Array<u2>* operands, int bootstrap_specifier_index, int offset) {
 562     int n = bootstrap_specifier_index * 2;
 563     assert(n >= 0 && n+2 <= operands->length(), "oob");
 564     operands->at_put(n+0, extract_low_short_from_int(offset));
 565     operands->at_put(n+1, extract_high_short_from_int(offset));
 566   }
 567   static int operand_array_length(Array<u2>* operands) {
 568     if (operands == NULL || operands->length() == 0)  return 0;
 569     int second_part = operand_offset_at(operands, 0);
 570     return (second_part / 2);
 571   }
 572 
 573 #ifdef ASSERT
 574   // operand tuples fit together exactly, end to end
 575   static int operand_limit_at(Array<u2>* operands, int bootstrap_specifier_index) {
 576     int nextidx = bootstrap_specifier_index + 1;
 577     if (nextidx == operand_array_length(operands))
 578       return operands->length();
 579     else
 580       return operand_offset_at(operands, nextidx);
 581   }
 582   int invoke_dynamic_operand_limit(int which) {
 583     int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
 584     return operand_limit_at(operands(), bootstrap_specifier_index);
 585   }
 586 #endif //ASSERT
 587 
 588   // layout of InvokeDynamic bootstrap method specifier (in second part of operands array):
 589   enum {
 590          _indy_bsm_offset  = 0,  // CONSTANT_MethodHandle bsm
 591          _indy_argc_offset = 1,  // u2 argc
 592          _indy_argv_offset = 2   // u2 argv[argc]
 593   };
 594 
 595   // These functions are used in RedefineClasses for CP merge
 596 
 597   int operand_offset_at(int bootstrap_specifier_index) {
 598     assert(0 <= bootstrap_specifier_index &&
 599            bootstrap_specifier_index < operand_array_length(operands()),
 600            "Corrupted CP operands");
 601     return operand_offset_at(operands(), bootstrap_specifier_index);
 602   }
 603   int operand_bootstrap_method_ref_index_at(int bootstrap_specifier_index) {
 604     int offset = operand_offset_at(bootstrap_specifier_index);
 605     return operands()->at(offset + _indy_bsm_offset);
 606   }
 607   int operand_argument_count_at(int bootstrap_specifier_index) {
 608     int offset = operand_offset_at(bootstrap_specifier_index);
 609     int argc = operands()->at(offset + _indy_argc_offset);
 610     return argc;
 611   }
 612   int operand_argument_index_at(int bootstrap_specifier_index, int j) {
 613     int offset = operand_offset_at(bootstrap_specifier_index);
 614     return operands()->at(offset + _indy_argv_offset + j);
 615   }
 616   int operand_next_offset_at(int bootstrap_specifier_index) {
 617     int offset = operand_offset_at(bootstrap_specifier_index) + _indy_argv_offset
 618                    + operand_argument_count_at(bootstrap_specifier_index);
 619     return offset;
 620   }
 621   // Compare a bootsrap specifier in the operands arrays
 622   bool compare_operand_to(int bootstrap_specifier_index1, constantPoolHandle cp2,
 623                           int bootstrap_specifier_index2, TRAPS);
 624   // Find a bootsrap specifier in the operands array
 625   int find_matching_operand(int bootstrap_specifier_index, constantPoolHandle search_cp,
 626                             int operands_cur_len, TRAPS);
 627   // Resize the operands array with delta_len and delta_size
 628   void resize_operands(int delta_len, int delta_size, TRAPS);
 629   // Extend the operands array with the length and size of the ext_cp operands
 630   void extend_operands(constantPoolHandle ext_cp, TRAPS);
 631   // Shrink the operands array to a smaller array with new_len length
 632   void shrink_operands(int new_len, TRAPS);
 633 
 634 
 635   int invoke_dynamic_bootstrap_method_ref_index_at(int which) {
 636     assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
 637     int op_base = invoke_dynamic_operand_base(which);
 638     return operands()->at(op_base + _indy_bsm_offset);
 639   }
 640   int invoke_dynamic_argument_count_at(int which) {
 641     assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
 642     int op_base = invoke_dynamic_operand_base(which);
 643     int argc = operands()->at(op_base + _indy_argc_offset);
 644     DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc;
 645                int next_offset = invoke_dynamic_operand_limit(which));
 646     assert(end_offset == next_offset, "matched ending");
 647     return argc;
 648   }
 649   int invoke_dynamic_argument_index_at(int which, int j) {
 650     int op_base = invoke_dynamic_operand_base(which);
 651     DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset));
 652     assert((uint)j < (uint)argc, "oob");
 653     return operands()->at(op_base + _indy_argv_offset + j);
 654   }
 655 
 656   // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve,
 657   // name_and_type_ref_index_at) all expect to be passed indices obtained
 658   // directly from the bytecode.
 659   // If the indices are meant to refer to fields or methods, they are
 660   // actually rewritten constant pool cache indices.
 661   // The routine remap_instruction_operand_from_cache manages the adjustment
 662   // of these values back to constant pool indices.
 663 
 664   // There are also "uncached" versions which do not adjust the operand index; see below.
 665 
 666   // FIXME: Consider renaming these with a prefix "cached_" to make the distinction clear.
 667   // In a few cases (the verifier) there are uses before a cpcache has been built,
 668   // which are handled by a dynamic check in remap_instruction_operand_from_cache.
 669   // FIXME: Remove the dynamic check, and adjust all callers to specify the correct mode.
 670 
 671   // Lookup for entries consisting of (klass_index, name_and_type index)
 672   Klass* klass_ref_at(int which, TRAPS);
 673   Symbol* klass_ref_at_noresolve(int which);
 674   Symbol* name_ref_at(int which)                { return impl_name_ref_at(which, false); }
 675   Symbol* signature_ref_at(int which)           { return impl_signature_ref_at(which, false); }
 676 
 677   int klass_ref_index_at(int which)               { return impl_klass_ref_index_at(which, false); }
 678   int name_and_type_ref_index_at(int which)       { return impl_name_and_type_ref_index_at(which, false); }
 679 
 680   // Lookup for entries consisting of (name_index, signature_index)
 681   int name_ref_index_at(int which_nt);            // ==  low-order jshort of name_and_type_at(which_nt)
 682   int signature_ref_index_at(int which_nt);       // == high-order jshort of name_and_type_at(which_nt)
 683 
 684   BasicType basic_type_for_signature_at(int which);
 685 
 686   // Resolve string constants (to prevent allocation during compilation)
 687   void resolve_string_constants(TRAPS) {
 688     constantPoolHandle h_this(THREAD, this);
 689     resolve_string_constants_impl(h_this, CHECK);
 690   }
 691 
 692   // CDS support
 693   void remove_unshareable_info();
 694   void restore_unshareable_info(TRAPS);
 695   bool resolve_class_constants(TRAPS);
 696   // The ConstantPool vtable is restored by this call when the ConstantPool is
 697   // in the shared archive.  See patch_klass_vtables() in metaspaceShared.cpp for
 698   // all the gory details.  SA, dtrace and pstack helpers distinguish metadata
 699   // by their vtable.
 700   void restore_vtable() { guarantee(is_constantPool(), "vtable restored by this call"); }
 701 
 702  private:
 703   enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
 704  public:
 705 
 706   // Resolve late bound constants.
 707   oop resolve_constant_at(int index, TRAPS) {
 708     constantPoolHandle h_this(THREAD, this);
 709     return resolve_constant_at_impl(h_this, index, _no_index_sentinel, THREAD);
 710   }
 711 
 712   oop resolve_cached_constant_at(int cache_index, TRAPS) {
 713     constantPoolHandle h_this(THREAD, this);
 714     return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, THREAD);
 715   }
 716 
 717   oop resolve_possibly_cached_constant_at(int pool_index, TRAPS) {
 718     constantPoolHandle h_this(THREAD, this);
 719     return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, THREAD);
 720   }
 721 
 722   oop resolve_bootstrap_specifier_at(int index, TRAPS) {
 723     constantPoolHandle h_this(THREAD, this);
 724     return resolve_bootstrap_specifier_at_impl(h_this, index, THREAD);
 725   }
 726 
 727   // Klass name matches name at offset
 728   bool klass_name_at_matches(instanceKlassHandle k, int which);
 729 
 730   // Sizing
 731   int length() const                   { return _length; }
 732   void set_length(int length)          { _length = length; }
 733 
 734   // Tells whether index is within bounds.
 735   bool is_within_bounds(int index) const {
 736     return 0 <= index && index < length();
 737   }
 738 
 739   // Sizing (in words)
 740   static int header_size()             { return sizeof(ConstantPool)/HeapWordSize; }
 741   static int size(int length)          { return align_object_size(header_size() + length); }
 742   int size() const                     { return size(length()); }
 743 #if INCLUDE_SERVICES
 744   void collect_statistics(KlassSizeStats *sz) const;
 745 #endif
 746 
 747   friend class ClassFileParser;
 748   friend class SystemDictionary;
 749 
 750   // Used by compiler to prevent classloading.
 751   static Method*          method_at_if_loaded      (constantPoolHandle this_oop, int which);
 752   static bool       has_appendix_at_if_loaded      (constantPoolHandle this_oop, int which);
 753   static oop            appendix_at_if_loaded      (constantPoolHandle this_oop, int which);
 754   static bool    has_method_type_at_if_loaded      (constantPoolHandle this_oop, int which);
 755   static oop         method_type_at_if_loaded      (constantPoolHandle this_oop, int which);
 756   static Klass*            klass_at_if_loaded      (constantPoolHandle this_oop, int which);
 757   static Klass*        klass_ref_at_if_loaded      (constantPoolHandle this_oop, int which);
 758 
 759   // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
 760   // future by other Java code. These take constant pool indices rather than
 761   // constant pool cache indices as do the peer methods above.
 762   Symbol* uncached_klass_ref_at_noresolve(int which);
 763   Symbol* uncached_name_ref_at(int which)                 { return impl_name_ref_at(which, true); }
 764   Symbol* uncached_signature_ref_at(int which)            { return impl_signature_ref_at(which, true); }
 765   int       uncached_klass_ref_index_at(int which)          { return impl_klass_ref_index_at(which, true); }
 766   int       uncached_name_and_type_ref_index_at(int which)  { return impl_name_and_type_ref_index_at(which, true); }
 767 
 768   // Sharing
 769   int pre_resolve_shared_klasses(TRAPS);
 770 
 771   // Debugging
 772   const char* printable_name_at(int which) PRODUCT_RETURN0;
 773 
 774 #ifdef ASSERT
 775   enum { CPCACHE_INDEX_TAG = 0x10000 };  // helps keep CP cache indices distinct from CP indices
 776 #else
 777   enum { CPCACHE_INDEX_TAG = 0 };        // in product mode, this zero value is a no-op
 778 #endif //ASSERT
 779 
 780   static int decode_cpcache_index(int raw_index, bool invokedynamic_ok = false) {
 781     if (invokedynamic_ok && is_invokedynamic_index(raw_index))
 782       return decode_invokedynamic_index(raw_index);
 783     else
 784       return raw_index - CPCACHE_INDEX_TAG;
 785   }
 786 
 787  private:
 788 
 789   void set_resolved_references(jobject s) { _resolved_references = s; }
 790   Array<u2>* reference_map() const        { return _reference_map; }
 791   void set_reference_map(Array<u2>* o)    { _reference_map = o; }
 792 
 793   // patch JSR 292 resolved references after the class is linked.
 794   void patch_resolved_references(GrowableArray<Handle>* cp_patches);
 795 
 796   Symbol* impl_name_ref_at(int which, bool uncached);
 797   Symbol* impl_signature_ref_at(int which, bool uncached);
 798   int       impl_klass_ref_index_at(int which, bool uncached);
 799   int       impl_name_and_type_ref_index_at(int which, bool uncached);
 800 
 801   int remap_instruction_operand_from_cache(int operand);  // operand must be biased by CPCACHE_INDEX_TAG
 802 
 803   // Used while constructing constant pool (only by ClassFileParser)
 804   jint klass_index_at(int which) {
 805     assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
 806     return *int_at_addr(which);
 807   }
 808 
 809   jint string_index_at(int which) {
 810     assert(tag_at(which).is_string_index(), "Corrupted constant pool");
 811     return *int_at_addr(which);
 812   }
 813 
 814   // Performs the LinkResolver checks
 815   static void verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle klass, TRAPS);
 816 
 817   // Implementation of methods that needs an exposed 'this' pointer, in order to
 818   // handle GC while executing the method
 819   static Klass* klass_at_impl(constantPoolHandle this_oop, int which, TRAPS);
 820   static oop string_at_impl(constantPoolHandle this_oop, int which, int obj_index, TRAPS);
 821 
 822   // Resolve string constants (to prevent allocation during compilation)
 823   static void resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS);
 824 
 825   static oop resolve_constant_at_impl(constantPoolHandle this_oop, int index, int cache_index, TRAPS);
 826   static oop resolve_bootstrap_specifier_at_impl(constantPoolHandle this_oop, int index, TRAPS);
 827 
 828   // Exception handling
 829   static void throw_resolution_error(constantPoolHandle this_oop, int which, TRAPS);
 830   static Symbol* exception_message(constantPoolHandle this_oop, int which, constantTag tag, oop pending_exception);
 831   static void save_and_throw_exception(constantPoolHandle this_oop, int which, constantTag tag, TRAPS);
 832 
 833  public:
 834   // Merging ConstantPool* support:
 835   bool compare_entry_to(int index1, constantPoolHandle cp2, int index2, TRAPS);
 836   void copy_cp_to(int start_i, int end_i, constantPoolHandle to_cp, int to_i, TRAPS) {
 837     constantPoolHandle h_this(THREAD, this);
 838     copy_cp_to_impl(h_this, start_i, end_i, to_cp, to_i, THREAD);
 839   }
 840   static void copy_cp_to_impl(constantPoolHandle from_cp, int start_i, int end_i, constantPoolHandle to_cp, int to_i, TRAPS);
 841   static void copy_entry_to(constantPoolHandle from_cp, int from_i, constantPoolHandle to_cp, int to_i, TRAPS);
 842   static void copy_operands(constantPoolHandle from_cp, constantPoolHandle to_cp, TRAPS);
 843   int  find_matching_entry(int pattern_i, constantPoolHandle search_cp, TRAPS);
 844   int  version() const                    { return _saved._version; }
 845   void set_version(int version)           { _saved._version = version; }
 846   void increment_and_save_version(int version) {
 847     _saved._version = version >= 0 ? (version + 1) : version;  // keep overflow
 848   }
 849 
 850   void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; }
 851   int  resolved_reference_length() const  { return _saved._resolved_reference_length; }
 852   void set_lock(Monitor* lock)            { _lock = lock; }
 853   Monitor* lock()                         { return _lock; }
 854 
 855   // Decrease ref counts of symbols that are in the constant pool
 856   // when the holder class is unloaded
 857   void unreference_symbols();
 858 
 859   // Deallocate constant pool for RedefineClasses
 860   void deallocate_contents(ClassLoaderData* loader_data);
 861   void release_C_heap_structures();
 862 
 863   // JVMTI accesss - GetConstantPool, RetransformClasses, ...
 864   friend class JvmtiConstantPoolReconstituter;
 865 
 866  private:
 867   jint cpool_entry_size(jint idx);
 868   jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
 869 
 870   // Copy cpool bytes into byte array.
 871   // Returns:
 872   //  int > 0, count of the raw cpool bytes that have been copied
 873   //        0, OutOfMemory error
 874   //       -1, Internal error
 875   int  copy_cpool_bytes(int cpool_size,
 876                         SymbolHashMap* tbl,
 877                         unsigned char *bytes);
 878 
 879  public:
 880   // Verify
 881   void verify_on(outputStream* st);
 882 
 883   // Printing
 884   void print_on(outputStream* st) const;
 885   void print_value_on(outputStream* st) const;
 886   void print_entry_on(int index, outputStream* st);
 887 
 888   const char* internal_name() const { return "{constant pool}"; }
 889 
 890 #ifndef PRODUCT
 891   // Compile the world support
 892   static void preload_and_initialize_all_classes(ConstantPool* constant_pool, TRAPS);
 893 #endif
 894 };
 895 
 896 class SymbolHashMapEntry : public CHeapObj<mtSymbol> {
 897  private:
 898   unsigned int        _hash;   // 32-bit hash for item
 899   SymbolHashMapEntry* _next;   // Next element in the linked list for this bucket
 900   Symbol*             _symbol; // 1-st part of the mapping: symbol => value
 901   u2                  _value;  // 2-nd part of the mapping: symbol => value
 902 
 903  public:
 904   unsigned   int hash() const             { return _hash;   }
 905   void       set_hash(unsigned int hash)  { _hash = hash;   }
 906 
 907   SymbolHashMapEntry* next() const        { return _next;   }
 908   void set_next(SymbolHashMapEntry* next) { _next = next;   }
 909 
 910   Symbol*    symbol() const               { return _symbol; }
 911   void       set_symbol(Symbol* sym)      { _symbol = sym;  }
 912 
 913   u2         value() const                {  return _value; }
 914   void       set_value(u2 value)          { _value = value; }
 915 
 916   SymbolHashMapEntry(unsigned int hash, Symbol* symbol, u2 value)
 917     : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {}
 918 
 919 }; // End SymbolHashMapEntry class
 920 
 921 
 922 class SymbolHashMapBucket : public CHeapObj<mtSymbol> {
 923 
 924 private:
 925   SymbolHashMapEntry*    _entry;
 926 
 927 public:
 928   SymbolHashMapEntry* entry() const         {  return _entry; }
 929   void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
 930   void clear()                              { _entry = NULL;  }
 931 
 932 }; // End SymbolHashMapBucket class
 933 
 934 
 935 class SymbolHashMap: public CHeapObj<mtSymbol> {
 936 
 937  private:
 938   // Default number of entries in the table
 939   enum SymbolHashMap_Constants {
 940     _Def_HashMap_Size = 256
 941   };
 942 
 943   int                   _table_size;
 944   SymbolHashMapBucket*  _buckets;
 945 
 946   void initialize_table(int table_size) {
 947     _table_size = table_size;
 948     _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size, mtSymbol);
 949     for (int index = 0; index < table_size; index++) {
 950       _buckets[index].clear();
 951     }
 952   }
 953 
 954  public:
 955 
 956   int table_size() const        { return _table_size; }
 957 
 958   SymbolHashMap()               { initialize_table(_Def_HashMap_Size); }
 959   SymbolHashMap(int table_size) { initialize_table(table_size); }
 960 
 961   // hash P(31) from Kernighan & Ritchie
 962   static unsigned int compute_hash(const char* str, int len) {
 963     unsigned int hash = 0;
 964     while (len-- > 0) {
 965       hash = 31*hash + (unsigned) *str;
 966       str++;
 967     }
 968     return hash;
 969   }
 970 
 971   SymbolHashMapEntry* bucket(int i) {
 972     return _buckets[i].entry();
 973   }
 974 
 975   void add_entry(Symbol* sym, u2 value);
 976   SymbolHashMapEntry* find_entry(Symbol* sym);
 977 
 978   u2 symbol_to_value(Symbol* sym) {
 979     SymbolHashMapEntry *entry = find_entry(sym);
 980     return (entry == NULL) ? 0 : entry->value();
 981   }
 982 
 983   ~SymbolHashMap() {
 984     SymbolHashMapEntry* next;
 985     for (int i = 0; i < _table_size; i++) {
 986       for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) {
 987         next = cur->next();
 988         delete(cur);
 989       }
 990     }
 991     FREE_C_HEAP_ARRAY(SymbolHashMapBucket, _buckets, mtSymbol);
 992   }
 993 }; // End SymbolHashMap class
 994 
 995 #endif // SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP