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 /*

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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 #ifndef SHARE_VM_INTERPRETER_REWRITER_HPP

 #define SHARE_VM_INTERPRETER_REWRITER_HPP

 #include "memory/allocation.hpp"

 #include "runtime/handles.inline.hpp"

 #include "utilities/growableArray.hpp"

 // The Rewriter adds caches to the constant pool and rewrites bytecode indices

 // pointing into the constant pool for better interpreter performance.

 class Rewriter: public StackObj {

  private:

   instanceKlassHandle _klass;

   constantPoolHandle  _pool;

   Array<Method*>*     _methods;

   intArray            _cp_map;

   intStack            _cp_cache_map;        // for Methodref, Fieldref,

                                             // InterfaceMethodref and InvokeDynamic

   intArray            _reference_map;       // maps from cp index to resolved_refs index (or -1)

   intStack            _resolved_references_map;    // for strings, methodHandle, methodType

   intStack            _invokedynamic_references_map; // for invokedynamic resolved refs

   intArray            _method_handle_invokers;

   int                 _resolved_reference_limit;

   void init_maps(int length) {

     _cp_map.initialize(length, -1);

     // Choose an initial value large enough that we don't get frequent

     // calls to grow().

     _cp_cache_map.initialize(length / 2);

     // Also cache resolved objects, in another different cache.

     _reference_map.initialize(length, -1);

     _resolved_references_map.initialize(length / 2);

     _invokedynamic_references_map.initialize(length / 2);

     _resolved_reference_limit = -1;

     DEBUG_ONLY(_cp_cache_index_limit = -1);

   }

   int _cp_cache_index_limit;

   void record_map_limits() {

 #ifdef ASSERT

     // Record initial size of the two arrays generated for the CP cache:

     _cp_cache_index_limit = _cp_cache_map.length();

 #endif //ASSERT

     _resolved_reference_limit = _resolved_references_map.length();

   }

   int  cp_entry_to_cp_cache(int i) { assert(has_cp_cache(i), "oob"); return _cp_map[i]; }

   bool has_cp_cache(int i) { return (uint)i < (uint)_cp_map.length() && _cp_map[i] >= 0; }

   int add_cp_cache_entry(int cp_index) {

     assert(_pool->tag_at(cp_index).value() != JVM_CONSTANT_InvokeDynamic, "use indy version");

     assert(_cp_map[cp_index] == -1, "not twice on same cp_index");

     assert(_cp_cache_index_limit == -1, "do not add cache entries after first iteration");

     int cache_index = _cp_cache_map.append(cp_index);

     _cp_map.at_put(cp_index, cache_index);

     assert(cp_entry_to_cp_cache(cp_index) == cache_index, "");

     assert(cp_cache_entry_pool_index(cache_index) == cp_index, "");

     return cache_index;

   }

   // add a new CP cache entry beyond the normal cache (for invokedynamic only)

   int add_invokedynamic_cp_cache_entry(int cp_index) {

     assert(_pool->tag_at(cp_index).value() == JVM_CONSTANT_InvokeDynamic, "use non-indy version");

     assert(_cp_map[cp_index] == -1, "do not map from cp_index");

     assert(_cp_cache_index_limit >= 0, "add indy cache entries after first iteration");

     int cache_index = _cp_cache_map.append(cp_index);

     assert(cache_index >= _cp_cache_index_limit, "");

     // do not update _cp_map, since the mapping is one-to-many

     assert(cp_cache_entry_pool_index(cache_index) == cp_index, "");

     return cache_index;

   }

   // fix duplicated code later

   int  cp_entry_to_resolved_references(int cp_index) const {

     assert(has_entry_in_resolved_references(cp_index), "oob");

     return _reference_map[cp_index];

   }

   bool has_entry_in_resolved_references(int cp_index) const {

     return (uint)cp_index < (uint)_reference_map.length() && _reference_map[cp_index] >= 0;

   }

   // add a new entry to the resolved_references map

   int add_resolved_references_entry(int cp_index) {

     assert(_reference_map[cp_index] == -1, "not twice on same cp_index");

     assert(_resolved_reference_limit == -1, "do not add CP refs after first iteration");

     int ref_index = _resolved_references_map.append(cp_index);

     _reference_map.at_put(cp_index, ref_index);

     assert(cp_entry_to_resolved_references(cp_index) == ref_index, "");

     return ref_index;

   }

   // add a new entries to the resolved_references map (for invokedynamic and invokehandle only)

   int add_invokedynamic_resolved_references_entries(int cp_index, int cache_index) {

     assert(_resolved_reference_limit >= 0, "must add indy refs after first iteration");

     int ref_index = -1;

     for (int entry = 0; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {

       const int index = _resolved_references_map.append(cp_index);  // many-to-one

       assert(index >= _resolved_reference_limit, "");

       if (entry == 0) {

         ref_index = index;

       }

       assert((index - entry) == ref_index, "entries must be consecutive");

       _invokedynamic_references_map.at_put_grow(index, cache_index, -1);

     }

     return ref_index;

   }

   int resolved_references_entry_to_pool_index(int ref_index) {

     int cp_index = _resolved_references_map[ref_index];

     return cp_index;

   }

   // Access the contents of _cp_cache_map to determine CP cache layout.

   int cp_cache_entry_pool_index(int cache_index) {

     int cp_index = _cp_cache_map[cache_index];

       return cp_index;

   }

   // All the work goes in here:

   Rewriter(instanceKlassHandle klass, constantPoolHandle cpool, Array<Method*>* methods, TRAPS);

   void compute_index_maps();

   void make_constant_pool_cache(TRAPS);

   void scan_method(Method* m, bool reverse = false);

   void rewrite_Object_init(methodHandle m, TRAPS);

   void rewrite_member_reference(address bcp, int offset, bool reverse = false);

   void maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse = false);

   void rewrite_invokedynamic(address bcp, int offset, bool reverse = false);

   void maybe_rewrite_ldc(address bcp, int offset, bool is_wide, bool reverse = false);

   // Revert bytecodes in case of an exception.

   void restore_bytecodes();

   static methodHandle rewrite_jsrs(methodHandle m, TRAPS);

  public:

   // Driver routine:

   static void rewrite(instanceKlassHandle klass, TRAPS);

 };

 #endif // SHARE_VM_INTERPRETER_REWRITER_HPP