1 /*
   2  * Copyright (c) 1997, 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
  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/bytes.hpp"
  35 #include "utilities/constantTag.hpp"
  36 
  37 // A ConstantPool is an array containing class constants as described in the
  38 // class file.
  39 //
  40 // Most of the constant pool entries are written during class parsing, which
  41 // is safe.  For klass types, the constant pool entry is
  42 // modified when the entry is resolved.  If a klass constant pool
  43 // entry is read without a lock, only the resolved state guarantees that
  44 // the entry in the constant pool is a klass object and not a Symbol*.
  45 
  46 class SymbolHashMap;
  47 
  48 class CPSlot VALUE_OBJ_CLASS_SPEC {
  49   intptr_t _ptr;
  50  public:
  51   enum TagBits  { _resolved_value = 0, _symbol_bit = 1, _pseudo_bit = 2, _symbol_mask = 3 };
  52 
  53   CPSlot(intptr_t ptr): _ptr(ptr) {}
  54   CPSlot(Klass* ptr): _ptr((intptr_t)ptr) {}
  55   CPSlot(Symbol* ptr): _ptr((intptr_t)ptr | _symbol_bit) {}
  56   CPSlot(Symbol* ptr, int tag_bits): _ptr((intptr_t)ptr | tag_bits) {}
  57 
  58   intptr_t value()   { return _ptr; }
  59   bool is_resolved()      { return (_ptr & _symbol_bit ) == _resolved_value; }
  60   bool is_unresolved()    { return (_ptr & _symbol_bit ) != _resolved_value; }
  61   bool is_pseudo_string() { return (_ptr & _symbol_mask) == _symbol_bit + _pseudo_bit; }
  62 
  63   Symbol* get_symbol() {
  64     assert(is_unresolved(), "bad call");
  65     return (Symbol*)(_ptr & ~_symbol_mask);
  66   }
  67   Klass* get_klass() {
  68     assert(is_resolved(), "bad call");
  69     return (Klass*)_ptr;
  70   }
  71 };
  72 
  73 class KlassSizeStats;
  74 
  75 class ConstantPool : public Metadata {
  76   friend class VMStructs;
  77   friend class BytecodeInterpreter;  // Directly extracts a klass in the pool for fast instanceof/checkcast
  78   friend class Universe;             // For null constructor
  79  private:
  80   Array<u1>*           _tags;        // the tag array describing the constant pool's contents
  81   ConstantPoolCache*   _cache;       // the cache holding interpreter runtime information
  82   InstanceKlass*       _pool_holder; // the corresponding class
  83   Array<u2>*           _operands;    // for variable-sized (InvokeDynamic) nodes, usually empty
  84 
  85   // Array of resolved objects from the constant pool and map from resolved
  86   // object index to original constant pool index
  87   jobject              _resolved_references;
  88   Array<u2>*           _reference_map;
  89 
  90   enum {
  91     _has_preresolution = 1,           // Flags
  92     _on_stack          = 2
  93   };
  94 
  95   int                  _flags;  // old fashioned bit twiddling
  96   int                  _length; // number of elements in the array
  97 
  98   union {
  99     // set for CDS to restore resolved references
 100     int                _resolved_reference_length;
 101     // keeps version number for redefined classes (used in backtrace)
 102     int                _version;
 103   } _saved;
 104 
 105   void set_tags(Array<u1>* tags)               { _tags = tags; }
 106   void tag_at_put(int which, jbyte t)          { tags()->at_put(which, t); }
 107   void release_tag_at_put(int which, jbyte t)  { tags()->release_at_put(which, t); }
 108 
 109   u1* tag_addr_at(int which) const             { return tags()->adr_at(which); }
 110 
 111   void set_operands(Array<u2>* operands)       { _operands = operands; }
 112 
 113   int flags() const                            { return _flags; }
 114   void set_flags(int f)                        { _flags = f; }
 115 
 116  private:
 117   intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); }
 118 
 119   CPSlot slot_at(int which) {
 120     assert(is_within_bounds(which), "index out of bounds");
 121     // Uses volatile because the klass slot changes without a lock.
 122     volatile intptr_t adr = (intptr_t)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which));
 123     assert(adr != 0 || which == 0, "cp entry for klass should not be zero");
 124     return CPSlot(adr);
 125   }
 126 
 127   void slot_at_put(int which, CPSlot s) const {
 128     assert(is_within_bounds(which), "index out of bounds");
 129     assert(s.value() != 0, "Caught something");
 130     *(intptr_t*)&base()[which] = s.value();
 131   }
 132   intptr_t* obj_at_addr_raw(int which) const {
 133     assert(is_within_bounds(which), "index out of bounds");
 134     return (intptr_t*) &base()[which];
 135   }
 136 
 137   jint* int_at_addr(int which) const {
 138     assert(is_within_bounds(which), "index out of bounds");
 139     return (jint*) &base()[which];
 140   }
 141 
 142   jlong* long_at_addr(int which) const {
 143     assert(is_within_bounds(which), "index out of bounds");
 144     return (jlong*) &base()[which];
 145   }
 146 
 147   jfloat* float_at_addr(int which) const {
 148     assert(is_within_bounds(which), "index out of bounds");
 149     return (jfloat*) &base()[which];
 150   }
 151 
 152   jdouble* double_at_addr(int which) const {
 153     assert(is_within_bounds(which), "index out of bounds");
 154     return (jdouble*) &base()[which];
 155   }
 156 
 157   ConstantPool(Array<u1>* tags);
 158   ConstantPool() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
 159  public:
 160   static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS);
 161 
 162   bool is_constantPool() const volatile     { return true; }
 163 
 164   Array<u1>* tags() const                   { return _tags; }
 165   Array<u2>* operands() const               { return _operands; }
 166 
 167   bool has_preresolution() const            { return (_flags & _has_preresolution) != 0; }
 168   void set_has_preresolution()              { _flags |= _has_preresolution; }
 169 
 170   // Redefine classes support.  If a method refering to this constant pool
 171   // is on the executing stack, or as a handle in vm code, this constant pool
 172   // can't be removed from the set of previous versions saved in the instance
 173   // class.
 174   bool on_stack() const                      { return (_flags &_on_stack) != 0; }
 175   void set_on_stack(const bool value);
 176 
 177   // Klass holding pool
 178   InstanceKlass* pool_holder() const      { return _pool_holder; }
 179   void set_pool_holder(InstanceKlass* k)  { _pool_holder = k; }
 180   InstanceKlass** pool_holder_addr()      { return &_pool_holder; }
 181 
 182   // Interpreter runtime support
 183   ConstantPoolCache* cache() const        { return _cache; }
 184   void set_cache(ConstantPoolCache* cache){ _cache = cache; }
 185 
 186   // Create object cache in the constant pool
 187   void initialize_resolved_references(ClassLoaderData* loader_data,
 188                                       intStack reference_map,
 189                                       int constant_pool_map_length,
 190                                       TRAPS);
 191 
 192   // resolved strings, methodHandles and callsite objects from the constant pool
 193   objArrayOop resolved_references()  const;
 194   // mapping resolved object array indexes to cp indexes and back.
 195   int object_to_cp_index(int index)         { return _reference_map->at(index); }
 196   int cp_to_object_index(int index);
 197 
 198   // Invokedynamic indexes.
 199   // They must look completely different from normal indexes.
 200   // The main reason is that byte swapping is sometimes done on normal indexes.
 201   // Finally, it is helpful for debugging to tell the two apart.
 202   static bool is_invokedynamic_index(int i) { return (i < 0); }
 203   static int  decode_invokedynamic_index(int i) { assert(is_invokedynamic_index(i),  ""); return ~i; }
 204   static int  encode_invokedynamic_index(int i) { assert(!is_invokedynamic_index(i), ""); return ~i; }
 205 
 206 
 207   // The invokedynamic points at a CP cache entry.  This entry points back
 208   // at the original CP entry (CONSTANT_InvokeDynamic) and also (via f2) at an entry
 209   // in the resolved_references array (which provides the appendix argument).
 210   int invokedynamic_cp_cache_index(int index) const {
 211     assert (is_invokedynamic_index(index), "should be a invokedynamic index");
 212     int cache_index = decode_invokedynamic_index(index);
 213     return cache_index;
 214   }
 215   ConstantPoolCacheEntry* invokedynamic_cp_cache_entry_at(int index) const {
 216     // decode index that invokedynamic points to.
 217     int cp_cache_index = invokedynamic_cp_cache_index(index);
 218     return cache()->entry_at(cp_cache_index);
 219   }
 220 
 221   // Assembly code support
 222   static int tags_offset_in_bytes()         { return offset_of(ConstantPool, _tags); }
 223   static int cache_offset_in_bytes()        { return offset_of(ConstantPool, _cache); }
 224   static int pool_holder_offset_in_bytes()  { return offset_of(ConstantPool, _pool_holder); }
 225   static int resolved_references_offset_in_bytes() { return offset_of(ConstantPool, _resolved_references); }
 226 
 227   // Storing constants
 228 
 229   void klass_at_put(int which, Klass* k) {
 230     assert(k != NULL, "resolved class shouldn't be null");
 231     assert(is_within_bounds(which), "index out of bounds");
 232     OrderAccess::release_store_ptr((Klass* volatile *)obj_at_addr_raw(which), k);
 233     // The interpreter assumes when the tag is stored, the klass is resolved
 234     // and the Klass* is a klass rather than a Symbol*, so we need
 235     // hardware store ordering here.
 236     release_tag_at_put(which, JVM_CONSTANT_Class);
 237   }
 238 
 239   // For temporary use while constructing constant pool
 240   void klass_index_at_put(int which, int name_index) {
 241     tag_at_put(which, JVM_CONSTANT_ClassIndex);
 242     *int_at_addr(which) = name_index;
 243   }
 244 
 245   // Temporary until actual use
 246   void unresolved_klass_at_put(int which, Symbol* s) {
 247     release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
 248     slot_at_put(which, s);
 249   }
 250 
 251   void method_handle_index_at_put(int which, int ref_kind, int ref_index) {
 252     tag_at_put(which, JVM_CONSTANT_MethodHandle);
 253     *int_at_addr(which) = ((jint) ref_index<<16) | ref_kind;
 254   }
 255 
 256   void method_type_index_at_put(int which, int ref_index) {
 257     tag_at_put(which, JVM_CONSTANT_MethodType);
 258     *int_at_addr(which) = ref_index;
 259   }
 260 
 261   void invoke_dynamic_at_put(int which, int bootstrap_specifier_index, int name_and_type_index) {
 262     tag_at_put(which, JVM_CONSTANT_InvokeDynamic);
 263     *int_at_addr(which) = ((jint) name_and_type_index<<16) | bootstrap_specifier_index;
 264   }
 265 
 266   void unresolved_string_at_put(int which, Symbol* s) {
 267     release_tag_at_put(which, JVM_CONSTANT_String);
 268     slot_at_put(which, CPSlot(s, CPSlot::_symbol_bit));
 269   }
 270 
 271   void int_at_put(int which, jint i) {
 272     tag_at_put(which, JVM_CONSTANT_Integer);
 273     *int_at_addr(which) = i;
 274   }
 275 
 276   void long_at_put(int which, jlong l) {
 277     tag_at_put(which, JVM_CONSTANT_Long);
 278     // *long_at_addr(which) = l;
 279     Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
 280   }
 281 
 282   void float_at_put(int which, jfloat f) {
 283     tag_at_put(which, JVM_CONSTANT_Float);
 284     *float_at_addr(which) = f;
 285   }
 286 
 287   void double_at_put(int which, jdouble d) {
 288     tag_at_put(which, JVM_CONSTANT_Double);
 289     // *double_at_addr(which) = d;
 290     // u8 temp = *(u8*) &d;
 291     Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
 292   }
 293 
 294   Symbol** symbol_at_addr(int which) const {
 295     assert(is_within_bounds(which), "index out of bounds");
 296     return (Symbol**) &base()[which];
 297   }
 298 
 299   void symbol_at_put(int which, Symbol* s) {
 300     assert(s->refcount() != 0, "should have nonzero refcount");
 301     tag_at_put(which, JVM_CONSTANT_Utf8);
 302     *symbol_at_addr(which) = s;
 303   }
 304 
 305   void string_at_put(int which, int obj_index, oop str) {
 306     resolved_references()->obj_at_put(obj_index, str);
 307   }
 308 
 309   // For temporary use while constructing constant pool
 310   void string_index_at_put(int which, int string_index) {
 311     tag_at_put(which, JVM_CONSTANT_StringIndex);
 312     *int_at_addr(which) = string_index;
 313   }
 314 
 315   void field_at_put(int which, int class_index, int name_and_type_index) {
 316     tag_at_put(which, JVM_CONSTANT_Fieldref);
 317     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
 318   }
 319 
 320   void method_at_put(int which, int class_index, int name_and_type_index) {
 321     tag_at_put(which, JVM_CONSTANT_Methodref);
 322     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
 323   }
 324 
 325   void interface_method_at_put(int which, int class_index, int name_and_type_index) {
 326     tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
 327     *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;  // Not so nice
 328   }
 329 
 330   void name_and_type_at_put(int which, int name_index, int signature_index) {
 331     tag_at_put(which, JVM_CONSTANT_NameAndType);
 332     *int_at_addr(which) = ((jint) signature_index<<16) | name_index;  // Not so nice
 333   }
 334 
 335   // Tag query
 336 
 337   constantTag tag_at(int which) const { return (constantTag)tags()->at_acquire(which); }
 338 
 339   // Fetching constants
 340 
 341   Klass* klass_at(int which, TRAPS) {
 342     constantPoolHandle h_this(THREAD, this);
 343     return klass_at_impl(h_this, which, true, THREAD);
 344   }
 345 
 346   // Version of klass_at that doesn't save the resolution error, called during deopt
 347   Klass* klass_at_ignore_error(int which, TRAPS) {
 348     constantPoolHandle h_this(THREAD, this);
 349     return klass_at_impl(h_this, which, false, THREAD);
 350   }
 351 
 352   Symbol* klass_name_at(int which);  // Returns the name, w/o resolving.
 353 
 354   Klass* resolved_klass_at(int which) const {  // Used by Compiler
 355     guarantee(tag_at(which).is_klass(), "Corrupted constant pool");
 356     // Must do an acquire here in case another thread resolved the klass
 357     // behind our back, lest we later load stale values thru the oop.
 358     return CPSlot((Klass*)OrderAccess::load_ptr_acquire(obj_at_addr_raw(which))).get_klass();
 359   }
 360 
 361   // RedefineClasses() API support:
 362   Symbol* klass_at_noresolve(int which) { return klass_name_at(which); }
 363 
 364   jint int_at(int which) {
 365     assert(tag_at(which).is_int(), "Corrupted constant pool");
 366     return *int_at_addr(which);
 367   }
 368 
 369   jlong long_at(int which) {
 370     assert(tag_at(which).is_long(), "Corrupted constant pool");
 371     // return *long_at_addr(which);
 372     u8 tmp = Bytes::get_native_u8((address)&base()[which]);
 373     return *((jlong*)&tmp);
 374   }
 375 
 376   jfloat float_at(int which) {
 377     assert(tag_at(which).is_float(), "Corrupted constant pool");
 378     return *float_at_addr(which);
 379   }
 380 
 381   jdouble double_at(int which) {
 382     assert(tag_at(which).is_double(), "Corrupted constant pool");
 383     u8 tmp = Bytes::get_native_u8((address)&base()[which]);
 384     return *((jdouble*)&tmp);
 385   }
 386 
 387   Symbol* symbol_at(int which) {
 388     assert(tag_at(which).is_utf8(), "Corrupted constant pool");
 389     return *symbol_at_addr(which);
 390   }
 391 
 392   oop string_at(int which, int obj_index, TRAPS) {
 393     constantPoolHandle h_this(THREAD, this);
 394     return string_at_impl(h_this, which, obj_index, THREAD);
 395   }
 396   oop string_at(int which, TRAPS) {
 397     int obj_index = cp_to_object_index(which);
 398     return string_at(which, obj_index, THREAD);
 399   }
 400 
 401   // Version that can be used before string oop array is created.
 402   oop uncached_string_at(int which, TRAPS);
 403 
 404   // A "pseudo-string" is an non-string oop that has found its way into
 405   // a String entry.
 406   // This can happen if the user patches a live
 407   // object into a CONSTANT_String entry of an anonymous class.
 408   // Method oops internally created for method handles may also
 409   // use pseudo-strings to link themselves to related metaobjects.
 410 
 411   bool is_pseudo_string_at(int which) {
 412     assert(tag_at(which).is_string(), "Corrupted constant pool");
 413     return slot_at(which).is_pseudo_string();
 414   }
 415 
 416   oop pseudo_string_at(int which, int obj_index) {
 417     assert(is_pseudo_string_at(which), "must be a pseudo-string");
 418     oop s = resolved_references()->obj_at(obj_index);
 419     return s;
 420   }
 421 
 422   oop pseudo_string_at(int which) {
 423     assert(is_pseudo_string_at(which), "must be a pseudo-string");
 424     int obj_index = cp_to_object_index(which);
 425     oop s = resolved_references()->obj_at(obj_index);
 426     return s;
 427   }
 428 
 429   void pseudo_string_at_put(int which, int obj_index, oop x) {
 430     assert(tag_at(which).is_string(), "Corrupted constant pool");
 431     Symbol* sym = unresolved_string_at(which);
 432     slot_at_put(which, CPSlot(sym, (CPSlot::_symbol_bit | CPSlot::_pseudo_bit)));
 433     string_at_put(which, obj_index, x);    // this works just fine
 434   }
 435 
 436   // only called when we are sure a string entry is already resolved (via an
 437   // earlier string_at call.
 438   oop resolved_string_at(int which) {
 439     assert(tag_at(which).is_string(), "Corrupted constant pool");
 440     // Must do an acquire here in case another thread resolved the klass
 441     // behind our back, lest we later load stale values thru the oop.
 442     // we might want a volatile_obj_at in ObjArrayKlass.
 443     int obj_index = cp_to_object_index(which);
 444     return resolved_references()->obj_at(obj_index);
 445   }
 446 
 447   Symbol* unresolved_string_at(int which) {
 448     assert(tag_at(which).is_string(), "Corrupted constant pool");
 449     Symbol* sym = slot_at(which).get_symbol();
 450     return sym;
 451   }
 452 
 453   // Returns an UTF8 for a CONSTANT_String entry at a given index.
 454   // UTF8 char* representation was chosen to avoid conversion of
 455   // java_lang_Strings at resolved entries into Symbol*s
 456   // or vice versa.
 457   char* string_at_noresolve(int which);
 458 
 459   jint name_and_type_at(int which) {
 460     assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
 461     return *int_at_addr(which);
 462   }
 463 
 464  private:
 465   int method_handle_ref_kind_at(int which, bool error_ok) {
 466     assert(tag_at(which).is_method_handle() ||
 467            (error_ok && tag_at(which).is_method_handle_in_error()), "Corrupted constant pool");
 468     return extract_low_short_from_int(*int_at_addr(which));  // mask out unwanted ref_index bits
 469   }
 470   int method_handle_index_at(int which, bool error_ok) {
 471     assert(tag_at(which).is_method_handle() ||
 472            (error_ok && tag_at(which).is_method_handle_in_error()), "Corrupted constant pool");
 473     return extract_high_short_from_int(*int_at_addr(which));  // shift out unwanted ref_kind bits
 474   }
 475   int method_type_index_at(int which, bool error_ok) {
 476     assert(tag_at(which).is_method_type() ||
 477            (error_ok && tag_at(which).is_method_type_in_error()), "Corrupted constant pool");
 478     return *int_at_addr(which);
 479   }
 480  public:
 481   int method_handle_ref_kind_at(int which) {
 482     return method_handle_ref_kind_at(which, false);
 483   }
 484   int method_handle_ref_kind_at_error_ok(int which) {
 485     return method_handle_ref_kind_at(which, true);
 486   }
 487   int method_handle_index_at(int which) {
 488     return method_handle_index_at(which, false);
 489   }
 490   int method_handle_index_at_error_ok(int which) {
 491     return method_handle_index_at(which, true);
 492   }
 493   int method_type_index_at(int which) {
 494     return method_type_index_at(which, false);
 495   }
 496   int method_type_index_at_error_ok(int which) {
 497     return method_type_index_at(which, true);
 498   }
 499 
 500   // Derived queries:
 501   Symbol* method_handle_name_ref_at(int which) {
 502     int member = method_handle_index_at(which);
 503     return impl_name_ref_at(member, true);
 504   }
 505   Symbol* method_handle_signature_ref_at(int which) {
 506     int member = method_handle_index_at(which);
 507     return impl_signature_ref_at(member, true);
 508   }
 509   int method_handle_klass_index_at(int which) {
 510     int member = method_handle_index_at(which);
 511     return impl_klass_ref_index_at(member, true);
 512   }
 513   Symbol* method_type_signature_at(int which) {
 514     int sym = method_type_index_at(which);
 515     return symbol_at(sym);
 516   }
 517 
 518   int invoke_dynamic_name_and_type_ref_index_at(int which) {
 519     assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
 520     return extract_high_short_from_int(*int_at_addr(which));
 521   }
 522   int invoke_dynamic_bootstrap_specifier_index(int which) {
 523     assert(tag_at(which).value() == JVM_CONSTANT_InvokeDynamic, "Corrupted constant pool");
 524     return extract_low_short_from_int(*int_at_addr(which));
 525   }
 526   int invoke_dynamic_operand_base(int which) {
 527     int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
 528     return operand_offset_at(operands(), bootstrap_specifier_index);
 529   }
 530   // The first part of the operands array consists of an index into the second part.
 531   // Extract a 32-bit index value from the first part.
 532   static int operand_offset_at(Array<u2>* operands, int bootstrap_specifier_index) {
 533     int n = (bootstrap_specifier_index * 2);
 534     assert(n >= 0 && n+2 <= operands->length(), "oob");
 535     // The first 32-bit index points to the beginning of the second part
 536     // of the operands array.  Make sure this index is in the first part.
 537     DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0),
 538                                                        operands->at(1)));
 539     assert(second_part == 0 || n+2 <= second_part, "oob (2)");
 540     int offset = build_int_from_shorts(operands->at(n+0),
 541                                        operands->at(n+1));
 542     // The offset itself must point into the second part of the array.
 543     assert(offset == 0 || offset >= second_part && offset <= operands->length(), "oob (3)");
 544     return offset;
 545   }
 546   static void operand_offset_at_put(Array<u2>* operands, int bootstrap_specifier_index, int offset) {
 547     int n = bootstrap_specifier_index * 2;
 548     assert(n >= 0 && n+2 <= operands->length(), "oob");
 549     operands->at_put(n+0, extract_low_short_from_int(offset));
 550     operands->at_put(n+1, extract_high_short_from_int(offset));
 551   }
 552   static int operand_array_length(Array<u2>* operands) {
 553     if (operands == NULL || operands->length() == 0)  return 0;
 554     int second_part = operand_offset_at(operands, 0);
 555     return (second_part / 2);
 556   }
 557 
 558 #ifdef ASSERT
 559   // operand tuples fit together exactly, end to end
 560   static int operand_limit_at(Array<u2>* operands, int bootstrap_specifier_index) {
 561     int nextidx = bootstrap_specifier_index + 1;
 562     if (nextidx == operand_array_length(operands))
 563       return operands->length();
 564     else
 565       return operand_offset_at(operands, nextidx);
 566   }
 567   int invoke_dynamic_operand_limit(int which) {
 568     int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which);
 569     return operand_limit_at(operands(), bootstrap_specifier_index);
 570   }
 571 #endif //ASSERT
 572 
 573   // layout of InvokeDynamic bootstrap method specifier (in second part of operands array):
 574   enum {
 575          _indy_bsm_offset  = 0,  // CONSTANT_MethodHandle bsm
 576          _indy_argc_offset = 1,  // u2 argc
 577          _indy_argv_offset = 2   // u2 argv[argc]
 578   };
 579 
 580   // These functions are used in RedefineClasses for CP merge
 581 
 582   int operand_offset_at(int bootstrap_specifier_index) {
 583     assert(0 <= bootstrap_specifier_index &&
 584            bootstrap_specifier_index < operand_array_length(operands()),
 585            "Corrupted CP operands");
 586     return operand_offset_at(operands(), bootstrap_specifier_index);
 587   }
 588   int operand_bootstrap_method_ref_index_at(int bootstrap_specifier_index) {
 589     int offset = operand_offset_at(bootstrap_specifier_index);
 590     return operands()->at(offset + _indy_bsm_offset);
 591   }
 592   int operand_argument_count_at(int bootstrap_specifier_index) {
 593     int offset = operand_offset_at(bootstrap_specifier_index);
 594     int argc = operands()->at(offset + _indy_argc_offset);
 595     return argc;
 596   }
 597   int operand_argument_index_at(int bootstrap_specifier_index, int j) {
 598     int offset = operand_offset_at(bootstrap_specifier_index);
 599     return operands()->at(offset + _indy_argv_offset + j);
 600   }
 601   int operand_next_offset_at(int bootstrap_specifier_index) {
 602     int offset = operand_offset_at(bootstrap_specifier_index) + _indy_argv_offset
 603                    + operand_argument_count_at(bootstrap_specifier_index);
 604     return offset;
 605   }
 606   // Compare a bootsrap specifier in the operands arrays
 607   bool compare_operand_to(int bootstrap_specifier_index1, constantPoolHandle cp2,
 608                           int bootstrap_specifier_index2, TRAPS);
 609   // Find a bootsrap specifier in the operands array
 610   int find_matching_operand(int bootstrap_specifier_index, constantPoolHandle search_cp,
 611                             int operands_cur_len, TRAPS);
 612   // Resize the operands array with delta_len and delta_size
 613   void resize_operands(int delta_len, int delta_size, TRAPS);
 614   // Extend the operands array with the length and size of the ext_cp operands
 615   void extend_operands(constantPoolHandle ext_cp, TRAPS);
 616   // Shrink the operands array to a smaller array with new_len length
 617   void shrink_operands(int new_len, TRAPS);
 618 
 619 
 620   int invoke_dynamic_bootstrap_method_ref_index_at(int which) {
 621     assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
 622     int op_base = invoke_dynamic_operand_base(which);
 623     return operands()->at(op_base + _indy_bsm_offset);
 624   }
 625   int invoke_dynamic_argument_count_at(int which) {
 626     assert(tag_at(which).is_invoke_dynamic(), "Corrupted constant pool");
 627     int op_base = invoke_dynamic_operand_base(which);
 628     int argc = operands()->at(op_base + _indy_argc_offset);
 629     DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc;
 630                int next_offset = invoke_dynamic_operand_limit(which));
 631     assert(end_offset == next_offset, "matched ending");
 632     return argc;
 633   }
 634   int invoke_dynamic_argument_index_at(int which, int j) {
 635     int op_base = invoke_dynamic_operand_base(which);
 636     DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset));
 637     assert((uint)j < (uint)argc, "oob");
 638     return operands()->at(op_base + _indy_argv_offset + j);
 639   }
 640 
 641   // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve,
 642   // name_and_type_ref_index_at) all expect to be passed indices obtained
 643   // directly from the bytecode.
 644   // If the indices are meant to refer to fields or methods, they are
 645   // actually rewritten constant pool cache indices.
 646   // The routine remap_instruction_operand_from_cache manages the adjustment
 647   // of these values back to constant pool indices.
 648 
 649   // There are also "uncached" versions which do not adjust the operand index; see below.
 650 
 651   // FIXME: Consider renaming these with a prefix "cached_" to make the distinction clear.
 652   // In a few cases (the verifier) there are uses before a cpcache has been built,
 653   // which are handled by a dynamic check in remap_instruction_operand_from_cache.
 654   // FIXME: Remove the dynamic check, and adjust all callers to specify the correct mode.
 655 
 656   // Lookup for entries consisting of (klass_index, name_and_type index)
 657   Klass* klass_ref_at(int which, TRAPS);
 658   Symbol* klass_ref_at_noresolve(int which);
 659   Symbol* name_ref_at(int which)                { return impl_name_ref_at(which, false); }
 660   Symbol* signature_ref_at(int which)           { return impl_signature_ref_at(which, false); }
 661 
 662   int klass_ref_index_at(int which)               { return impl_klass_ref_index_at(which, false); }
 663   int name_and_type_ref_index_at(int which)       { return impl_name_and_type_ref_index_at(which, false); }
 664 
 665   int remap_instruction_operand_from_cache(int operand);  // operand must be biased by CPCACHE_INDEX_TAG
 666 
 667   // Lookup for entries consisting of (name_index, signature_index)
 668   int name_ref_index_at(int which_nt);            // ==  low-order jshort of name_and_type_at(which_nt)
 669   int signature_ref_index_at(int which_nt);       // == high-order jshort of name_and_type_at(which_nt)
 670 
 671   BasicType basic_type_for_signature_at(int which);
 672 
 673   // Resolve string constants (to prevent allocation during compilation)
 674   void resolve_string_constants(TRAPS) {
 675     constantPoolHandle h_this(THREAD, this);
 676     resolve_string_constants_impl(h_this, CHECK);
 677   }
 678 
 679   // CDS support
 680   void remove_unshareable_info();
 681   void restore_unshareable_info(TRAPS);
 682   bool resolve_class_constants(TRAPS);
 683   // The ConstantPool vtable is restored by this call when the ConstantPool is
 684   // in the shared archive.  See patch_klass_vtables() in metaspaceShared.cpp for
 685   // all the gory details.  SA, dtrace and pstack helpers distinguish metadata
 686   // by their vtable.
 687   void restore_vtable() { guarantee(is_constantPool(), "vtable restored by this call"); }
 688 
 689  private:
 690   enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 };
 691  public:
 692 
 693   // Resolve late bound constants.
 694   oop resolve_constant_at(int index, TRAPS) {
 695     constantPoolHandle h_this(THREAD, this);
 696     return resolve_constant_at_impl(h_this, index, _no_index_sentinel, THREAD);
 697   }
 698 
 699   oop resolve_cached_constant_at(int cache_index, TRAPS) {
 700     constantPoolHandle h_this(THREAD, this);
 701     return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, THREAD);
 702   }
 703 
 704   oop resolve_possibly_cached_constant_at(int pool_index, TRAPS) {
 705     constantPoolHandle h_this(THREAD, this);
 706     return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, THREAD);
 707   }
 708 
 709   oop resolve_bootstrap_specifier_at(int index, TRAPS) {
 710     constantPoolHandle h_this(THREAD, this);
 711     return resolve_bootstrap_specifier_at_impl(h_this, index, THREAD);
 712   }
 713 
 714   // Klass name matches name at offset
 715   bool klass_name_at_matches(instanceKlassHandle k, int which);
 716 
 717   // Sizing
 718   int length() const                   { return _length; }
 719   void set_length(int length)          { _length = length; }
 720 
 721   // Tells whether index is within bounds.
 722   bool is_within_bounds(int index) const {
 723     return 0 <= index && index < length();
 724   }
 725 
 726   // Sizing (in words)
 727   static int header_size()             { return sizeof(ConstantPool)/HeapWordSize; }
 728   static int size(int length)          { return align_object_size(header_size() + length); }
 729   int size() const                     { return size(length()); }
 730 #if INCLUDE_SERVICES
 731   void collect_statistics(KlassSizeStats *sz) const;
 732 #endif
 733 
 734   friend class ClassFileParser;
 735   friend class SystemDictionary;
 736 
 737   // Used by compiler to prevent classloading.
 738   static Method*          method_at_if_loaded      (constantPoolHandle this_cp, int which);
 739   static bool       has_appendix_at_if_loaded      (constantPoolHandle this_cp, int which);
 740   static oop            appendix_at_if_loaded      (constantPoolHandle this_cp, int which);
 741   static bool    has_method_type_at_if_loaded      (constantPoolHandle this_cp, int which);
 742   static oop         method_type_at_if_loaded      (constantPoolHandle this_cp, int which);
 743   static Klass*            klass_at_if_loaded      (constantPoolHandle this_cp, int which);
 744   static Klass*        klass_ref_at_if_loaded      (constantPoolHandle this_cp, int which);
 745 
 746   // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
 747   // future by other Java code. These take constant pool indices rather than
 748   // constant pool cache indices as do the peer methods above.
 749   Symbol* uncached_klass_ref_at_noresolve(int which);
 750   Symbol* uncached_name_ref_at(int which)                 { return impl_name_ref_at(which, true); }
 751   Symbol* uncached_signature_ref_at(int which)            { return impl_signature_ref_at(which, true); }
 752   int       uncached_klass_ref_index_at(int which)          { return impl_klass_ref_index_at(which, true); }
 753   int       uncached_name_and_type_ref_index_at(int which)  { return impl_name_and_type_ref_index_at(which, true); }
 754 
 755   // Sharing
 756   int pre_resolve_shared_klasses(TRAPS);
 757 
 758   // Debugging
 759   const char* printable_name_at(int which) PRODUCT_RETURN0;
 760 
 761 #ifdef ASSERT
 762   enum { CPCACHE_INDEX_TAG = 0x10000 };  // helps keep CP cache indices distinct from CP indices
 763 #else
 764   enum { CPCACHE_INDEX_TAG = 0 };        // in product mode, this zero value is a no-op
 765 #endif //ASSERT
 766 
 767   static int decode_cpcache_index(int raw_index, bool invokedynamic_ok = false) {
 768     if (invokedynamic_ok && is_invokedynamic_index(raw_index))
 769       return decode_invokedynamic_index(raw_index);
 770     else
 771       return raw_index - CPCACHE_INDEX_TAG;
 772   }
 773 
 774  private:
 775 
 776   void set_resolved_references(jobject s) { _resolved_references = s; }
 777   Array<u2>* reference_map() const        { return _reference_map; }
 778   void set_reference_map(Array<u2>* o)    { _reference_map = o; }
 779 
 780   // patch JSR 292 resolved references after the class is linked.
 781   void patch_resolved_references(GrowableArray<Handle>* cp_patches);
 782 
 783   Symbol* impl_name_ref_at(int which, bool uncached);
 784   Symbol* impl_signature_ref_at(int which, bool uncached);
 785   int       impl_klass_ref_index_at(int which, bool uncached);
 786   int       impl_name_and_type_ref_index_at(int which, bool uncached);
 787 


 788   // Used while constructing constant pool (only by ClassFileParser)
 789   jint klass_index_at(int which) {
 790     assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
 791     return *int_at_addr(which);
 792   }
 793 
 794   jint string_index_at(int which) {
 795     assert(tag_at(which).is_string_index(), "Corrupted constant pool");
 796     return *int_at_addr(which);
 797   }
 798 
 799   // Performs the LinkResolver checks
 800   static void verify_constant_pool_resolve(constantPoolHandle this_cp, KlassHandle klass, TRAPS);
 801 
 802   // Implementation of methods that needs an exposed 'this' pointer, in order to
 803   // handle GC while executing the method
 804   static Klass* klass_at_impl(constantPoolHandle this_cp, int which,
 805                               bool save_resolution_error, TRAPS);
 806   static oop string_at_impl(constantPoolHandle this_cp, int which, int obj_index, TRAPS);
 807 
 808   static void trace_class_resolution(constantPoolHandle this_cp, KlassHandle k);
 809 
 810   // Resolve string constants (to prevent allocation during compilation)
 811   static void resolve_string_constants_impl(constantPoolHandle this_cp, TRAPS);
 812 
 813   static oop resolve_constant_at_impl(constantPoolHandle this_cp, int index, int cache_index, TRAPS);
 814   static oop resolve_bootstrap_specifier_at_impl(constantPoolHandle this_cp, int index, TRAPS);
 815 
 816   // Exception handling
 817   static void throw_resolution_error(constantPoolHandle this_cp, int which, TRAPS);
 818   static Symbol* exception_message(constantPoolHandle this_cp, int which, constantTag tag, oop pending_exception);
 819   static void save_and_throw_exception(constantPoolHandle this_cp, int which, constantTag tag, TRAPS);
 820 
 821  public:
 822   // Merging ConstantPool* support:
 823   bool compare_entry_to(int index1, constantPoolHandle cp2, int index2, TRAPS);
 824   void copy_cp_to(int start_i, int end_i, constantPoolHandle to_cp, int to_i, TRAPS) {
 825     constantPoolHandle h_this(THREAD, this);
 826     copy_cp_to_impl(h_this, start_i, end_i, to_cp, to_i, THREAD);
 827   }
 828   static void copy_cp_to_impl(constantPoolHandle from_cp, int start_i, int end_i, constantPoolHandle to_cp, int to_i, TRAPS);
 829   static void copy_entry_to(constantPoolHandle from_cp, int from_i, constantPoolHandle to_cp, int to_i, TRAPS);
 830   static void copy_operands(constantPoolHandle from_cp, constantPoolHandle to_cp, TRAPS);
 831   int  find_matching_entry(int pattern_i, constantPoolHandle search_cp, TRAPS);
 832   int  version() const                    { return _saved._version; }
 833   void set_version(int version)           { _saved._version = version; }
 834   void increment_and_save_version(int version) {
 835     _saved._version = version >= 0 ? (version + 1) : version;  // keep overflow
 836   }
 837 
 838   void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; }
 839   int  resolved_reference_length() const  { return _saved._resolved_reference_length; }
 840 
 841   // Decrease ref counts of symbols that are in the constant pool
 842   // when the holder class is unloaded
 843   void unreference_symbols();
 844 
 845   // Deallocate constant pool for RedefineClasses
 846   void deallocate_contents(ClassLoaderData* loader_data);
 847   void release_C_heap_structures();
 848 
 849   // JVMTI accesss - GetConstantPool, RetransformClasses, ...
 850   friend class JvmtiConstantPoolReconstituter;
 851 
 852  private:
 853   jint cpool_entry_size(jint idx);
 854   jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
 855 
 856   // Copy cpool bytes into byte array.
 857   // Returns:
 858   //  int > 0, count of the raw cpool bytes that have been copied
 859   //        0, OutOfMemory error
 860   //       -1, Internal error
 861   int  copy_cpool_bytes(int cpool_size,
 862                         SymbolHashMap* tbl,
 863                         unsigned char *bytes);
 864 
 865  public:
 866   // Verify
 867   void verify_on(outputStream* st);
 868 
 869   // Printing
 870   void print_on(outputStream* st) const;
 871   void print_value_on(outputStream* st) const;
 872   void print_entry_on(int index, outputStream* st);
 873 
 874   const char* internal_name() const { return "{constant pool}"; }
 875 
 876 #ifndef PRODUCT
 877   // Compile the world support
 878   static void preload_and_initialize_all_classes(ConstantPool* constant_pool, TRAPS);
 879 #endif
 880 };
 881 
 882 class SymbolHashMapEntry : public CHeapObj<mtSymbol> {
 883  private:
 884   unsigned int        _hash;   // 32-bit hash for item
 885   SymbolHashMapEntry* _next;   // Next element in the linked list for this bucket
 886   Symbol*             _symbol; // 1-st part of the mapping: symbol => value
 887   u2                  _value;  // 2-nd part of the mapping: symbol => value
 888 
 889  public:
 890   unsigned   int hash() const             { return _hash;   }
 891   void       set_hash(unsigned int hash)  { _hash = hash;   }
 892 
 893   SymbolHashMapEntry* next() const        { return _next;   }
 894   void set_next(SymbolHashMapEntry* next) { _next = next;   }
 895 
 896   Symbol*    symbol() const               { return _symbol; }
 897   void       set_symbol(Symbol* sym)      { _symbol = sym;  }
 898 
 899   u2         value() const                {  return _value; }
 900   void       set_value(u2 value)          { _value = value; }
 901 
 902   SymbolHashMapEntry(unsigned int hash, Symbol* symbol, u2 value)
 903     : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {}
 904 
 905 }; // End SymbolHashMapEntry class
 906 
 907 
 908 class SymbolHashMapBucket : public CHeapObj<mtSymbol> {
 909 
 910 private:
 911   SymbolHashMapEntry*    _entry;
 912 
 913 public:
 914   SymbolHashMapEntry* entry() const         {  return _entry; }
 915   void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
 916   void clear()                              { _entry = NULL;  }
 917 
 918 }; // End SymbolHashMapBucket class
 919 
 920 
 921 class SymbolHashMap: public CHeapObj<mtSymbol> {
 922 
 923  private:
 924   // Default number of entries in the table
 925   enum SymbolHashMap_Constants {
 926     _Def_HashMap_Size = 256
 927   };
 928 
 929   int                   _table_size;
 930   SymbolHashMapBucket*  _buckets;
 931 
 932   void initialize_table(int table_size) {
 933     _table_size = table_size;
 934     _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size, mtSymbol);
 935     for (int index = 0; index < table_size; index++) {
 936       _buckets[index].clear();
 937     }
 938   }
 939 
 940  public:
 941 
 942   int table_size() const        { return _table_size; }
 943 
 944   SymbolHashMap()               { initialize_table(_Def_HashMap_Size); }
 945   SymbolHashMap(int table_size) { initialize_table(table_size); }
 946 
 947   // hash P(31) from Kernighan & Ritchie
 948   static unsigned int compute_hash(const char* str, int len) {
 949     unsigned int hash = 0;
 950     while (len-- > 0) {
 951       hash = 31*hash + (unsigned) *str;
 952       str++;
 953     }
 954     return hash;
 955   }
 956 
 957   SymbolHashMapEntry* bucket(int i) {
 958     return _buckets[i].entry();
 959   }
 960 
 961   void add_entry(Symbol* sym, u2 value);
 962   SymbolHashMapEntry* find_entry(Symbol* sym);
 963 
 964   u2 symbol_to_value(Symbol* sym) {
 965     SymbolHashMapEntry *entry = find_entry(sym);
 966     return (entry == NULL) ? 0 : entry->value();
 967   }
 968 
 969   ~SymbolHashMap() {
 970     SymbolHashMapEntry* next;
 971     for (int i = 0; i < _table_size; i++) {
 972       for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) {
 973         next = cur->next();
 974         delete(cur);
 975       }
 976     }
 977     delete _buckets;
 978   }
 979 }; // End SymbolHashMap class
 980 
 981 #endif // SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP
--- EOF ---