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

 *

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 *

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 * 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.

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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:

  InstanceKlass*      _klass;

  constantPoolHandle  _pool;

  Array<Method*>*     _methods;

  GrowableArray<int>  _cp_map;

  GrowableArray<int>  _cp_cache_map;  // for Methodref, Fieldref,

                                      // InterfaceMethodref and InvokeDynamic

  GrowableArray<int>  _reference_map; // maps from cp index to resolved_refs index (or -1)

  GrowableArray<int>  _resolved_references_map; // for strings, methodHandle, methodType

  GrowableArray<int>  _invokedynamic_references_map; // for invokedynamic resolved refs

  GrowableArray<int>  _method_handle_invokers;

  int                 _resolved_reference_limit;

  // For mapping invokedynamic bytecodes, which are discovered during method

  // scanning.  The invokedynamic entries are added at the end of the cpCache.

  // If there are any invokespecial/InterfaceMethodref special case bytecodes,

  // these entries are added before invokedynamic entries so that the

  // invokespecial bytecode 16 bit index doesn't overflow.

  GrowableArray<int>      _invokedynamic_cp_cache_map;

  // For patching.

  GrowableArray<address>* _patch_invokedynamic_bcps;

  GrowableArray<int>*     _patch_invokedynamic_refs;

  void init_maps(int length) {

    _cp_map.trunc_to(0);

    _cp_map.at_grow(length, -1);

    _cp_cache_map.trunc_to(0);

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

    _reference_map.trunc_to(0);

    _reference_map.at_grow(length, -1);

    _method_handle_invokers.trunc_to(0);

    _resolved_references_map.trunc_to(0);

    _invokedynamic_references_map.trunc_to(0);

    _resolved_reference_limit = -1;

    _first_iteration_cp_cache_limit = -1;

    // invokedynamic specific fields

    _invokedynamic_cp_cache_map.trunc_to(0);

    _patch_invokedynamic_bcps = new GrowableArray<address>(length / 4);

    _patch_invokedynamic_refs = new GrowableArray<int>(length / 4);

  }

  int _first_iteration_cp_cache_limit;

  void record_map_limits() {

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

    // relative to walking the constant pool.

    _first_iteration_cp_cache_limit = _cp_cache_map.length();

    _resolved_reference_limit = _resolved_references_map.length();

  }

  int cp_cache_delta() {

    // How many cp cache entries were added since recording map limits after

    // cp cache initialization?

    assert(_first_iteration_cp_cache_limit != -1, "only valid after first iteration");

    return _cp_cache_map.length() - _first_iteration_cp_cache_limit;

  }

  int  cp_entry_to_cp_cache(int i) { assert(has_cp_cache(i), "oob"); return _cp_map.at(i); }

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

  int add_map_entry(int cp_index, GrowableArray<int>* cp_map, GrowableArray<int>* cp_cache_map) {

    assert(cp_map->at(cp_index) == -1, "not twice on same cp_index");

    int cache_index = cp_cache_map->append(cp_index);

    cp_map->at_put(cp_index, cache_index);

    return cache_index;

  }

  int add_cp_cache_entry(int cp_index) {

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

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

    int cache_index = add_map_entry(cp_index, &_cp_map, &_cp_cache_map);

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

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

    return cache_index;

  }

  int add_invokedynamic_cp_cache_entry(int cp_index) {

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

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

    // add to the invokedynamic index map.

    int cache_index = _invokedynamic_cp_cache_map.append(cp_index);

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

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

    // this index starts at one but in the bytecode it's appended to the end.

    return cache_index + _first_iteration_cp_cache_limit;

  }

  int invokedynamic_cp_cache_entry_pool_index(int cache_index) {

    int cp_index = _invokedynamic_cp_cache_map.at(cache_index);

    return cp_index;

  }

  // add a new CP cache entry beyond the normal cache for the special case of

  // invokespecial with InterfaceMethodref as cpool operand.

  int add_invokespecial_cp_cache_entry(int cp_index) {

    assert(_first_iteration_cp_cache_limit >= 0, "add these special cache entries after first iteration");

    // Don't add InterfaceMethodref if it already exists at the end.

    for (int i = _first_iteration_cp_cache_limit; i < _cp_cache_map.length(); i++) {

      if (cp_cache_entry_pool_index(i) == cp_index) {

        return i;

      }

    }

    int cache_index = _cp_cache_map.append(cp_index);

    assert(cache_index >= _first_iteration_cp_cache_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;

  }

  int  cp_entry_to_resolved_references(int cp_index) const {

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

    return _reference_map.at(cp_index);

  }

  bool has_entry_in_resolved_references(int cp_index) const {

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

  }

  // add a new entry to the resolved_references map

  int add_resolved_references_entry(int cp_index) {

    int ref_index = add_map_entry(cp_index, &_reference_map, &_resolved_references_map);

    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.at(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.at(cache_index);

    return cp_index;

  }

  // All the work goes in here:

  Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS);

  void compute_index_maps();

  void make_constant_pool_cache(TRAPS);

  void scan_method(Method* m, bool reverse, bool* invokespecial_error);

  void rewrite_Object_init(const methodHandle& m, TRAPS);

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

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

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

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

  void rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error);

  void patch_invokedynamic_bytecodes();

  // Do all the work.

  void rewrite_bytecodes(TRAPS);

  // Revert bytecodes in case of an exception.

  void restore_bytecodes();

  static methodHandle rewrite_jsrs(const methodHandle& m, TRAPS);

 public:

  // Driver routine:

  static void rewrite(InstanceKlass* klass, TRAPS);

};

#endif // SHARE_VM_INTERPRETER_REWRITER_HPP