1 /*

     2  * Copyright (c) 1998, 2017, 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_INTERPRETER_REWRITER_HPP

    26 #define SHARE_VM_INTERPRETER_REWRITER_HPP

    27 

    28 #include "memory/allocation.hpp"

    29 #include "runtime/handles.inline.hpp"

    30 #include "utilities/growableArray.hpp"

    31 

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

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

    34 

    35 class Rewriter: public StackObj {

    36  private:

    37   InstanceKlass*      _klass;

    38   constantPoolHandle  _pool;

    39   Array<Method*>*     _methods;

    40   GrowableArray<int>  _cp_map;

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

    42                                       // InterfaceMethodref and InvokeDynamic

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

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

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

    46   GrowableArray<int>  _method_handle_invokers;

    47   int                 _resolved_reference_limit;

    48 

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

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

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

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

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

    54   GrowableArray<int>      _invokedynamic_cp_cache_map;

    55 

    56   // For patching.

    57   GrowableArray<address>* _patch_invokedynamic_bcps;

    58   GrowableArray<int>*     _patch_invokedynamic_refs;

    59 

    60   void init_maps(int length) {

    61     _cp_map.trunc_to(0);

    62     _cp_map.at_grow(length, -1);

    63 

    64     _cp_cache_map.trunc_to(0);

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

    66     _reference_map.trunc_to(0);

    67     _reference_map.at_grow(length, -1);

    68 

    69     _method_handle_invokers.trunc_to(0);

    70     _resolved_references_map.trunc_to(0);

    71     _invokedynamic_references_map.trunc_to(0);

    72     _resolved_reference_limit = -1;

    73     _first_iteration_cp_cache_limit = -1;

    74 

    75     // invokedynamic specific fields

    76     _invokedynamic_cp_cache_map.trunc_to(0);

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

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

    79   }

    80 

    81   int _first_iteration_cp_cache_limit;

    82   void record_map_limits() {

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

    84     // relative to walking the constant pool.

    85     _first_iteration_cp_cache_limit = _cp_cache_map.length();

    86     _resolved_reference_limit = _resolved_references_map.length();

    87   }

    88 

    89   int cp_cache_delta() {

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

    91     // cp cache initialization?

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

    93     return _cp_cache_map.length() - _first_iteration_cp_cache_limit;

    94   }

    95 

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

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

    98 

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

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

   101     int cache_index = cp_cache_map->append(cp_index);

   102     cp_map->at_put(cp_index, cache_index);

   103     return cache_index;

   104   }

   105 

   106   int add_cp_cache_entry(int cp_index) {

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

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

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

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

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

   112     return cache_index;

   113   }

   114 

   115   int add_invokedynamic_cp_cache_entry(int cp_index) {

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

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

   118     // add to the invokedynamic index map.

   119     int cache_index = _invokedynamic_cp_cache_map.append(cp_index);

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

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

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

   123     return cache_index + _first_iteration_cp_cache_limit;

   124   }

   125 

   126   int invokedynamic_cp_cache_entry_pool_index(int cache_index) {

   127     int cp_index = _invokedynamic_cp_cache_map.at(cache_index);

   128     return cp_index;

   129   }

   130 

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

   132   // invokespecial with InterfaceMethodref as cpool operand.

   133   int add_invokespecial_cp_cache_entry(int cp_index) {

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

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

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

   137       if (cp_cache_entry_pool_index(i) == cp_index) {

   138         return i;

   139       }

   140     }

   141     int cache_index = _cp_cache_map.append(cp_index);

   142     assert(cache_index >= _first_iteration_cp_cache_limit, "");

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

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

   145     return cache_index;

   146   }

   147 

   148   int  cp_entry_to_resolved_references(int cp_index) const {

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

   150     return _reference_map.at(cp_index);

   151   }

   152   bool has_entry_in_resolved_references(int cp_index) const {

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

   154   }

   155 

   156   // add a new entry to the resolved_references map

   157   int add_resolved_references_entry(int cp_index) {

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

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

   160     return ref_index;

   161   }

   162 

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

   164   int add_invokedynamic_resolved_references_entries(int cp_index, int cache_index) {

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

   166     int ref_index = -1;

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

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

   169       assert(index >= _resolved_reference_limit, "");

   170       if (entry == 0) {

   171         ref_index = index;

   172       }

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

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

   175     }

   176     return ref_index;

   177   }

   178 

   179   int resolved_references_entry_to_pool_index(int ref_index) {

   180     int cp_index = _resolved_references_map.at(ref_index);

   181     return cp_index;

   182   }

   183 

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

   185   int cp_cache_entry_pool_index(int cache_index) {

   186     int cp_index = _cp_cache_map.at(cache_index);

   187     return cp_index;

   188   }

   189 

   190   // All the work goes in here:

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

   192 

   193   void compute_index_maps();

   194   void make_constant_pool_cache(TRAPS);

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

   196   void rewrite_Object_init(const methodHandle& m, TRAPS);

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

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

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

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

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

   202 

   203   void patch_invokedynamic_bytecodes();

   204 

   205   // Do all the work.

   206   void rewrite_bytecodes(TRAPS);

   207 

   208   // Revert bytecodes in case of an exception.

   209   void restore_bytecodes();

   210 

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

   212  public:

   213   // Driver routine:

   214   static void rewrite(InstanceKlass* klass, TRAPS);

   215 };

   216 

   217 #endif // SHARE_VM_INTERPRETER_REWRITER_HPP