1 /*
   2  * Copyright (c) 1997, 2014, 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 #include "precompiled.hpp"
  26 #include "code/vtableStubs.hpp"
  27 #include "compiler/disassembler.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 #include "memory/resourceArea.hpp"
  30 #include "oops/instanceKlass.hpp"
  31 #include "oops/klassVtable.hpp"
  32 #include "oops/oop.inline.hpp"
  33 #include "prims/forte.hpp"
  34 #include "prims/jvmtiExport.hpp"
  35 #include "runtime/handles.inline.hpp"
  36 #include "runtime/mutexLocker.hpp"
  37 #include "runtime/sharedRuntime.hpp"
  38 #ifdef COMPILER2
  39 #include "opto/matcher.hpp"
  40 #endif
  41 
  42 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  43 
  44 // -----------------------------------------------------------------------------------------
  45 // Implementation of VtableStub
  46 
  47 address VtableStub::_chunk             = NULL;
  48 address VtableStub::_chunk_end         = NULL;
  49 VMReg   VtableStub::_receiver_location = VMRegImpl::Bad();
  50 
  51 
  52 void* VtableStub::operator new(size_t size, int code_size) throw() {
  53   assert(size == sizeof(VtableStub), "mismatched size");
  54   // compute real VtableStub size (rounded to nearest word)
  55   const int real_size = round_to(code_size + sizeof(VtableStub), wordSize);
  56   // malloc them in chunks to minimize header overhead
  57   const int chunk_factor = 32;
  58   if (_chunk == NULL || _chunk + real_size > _chunk_end) {
  59     const int bytes = chunk_factor * real_size + pd_code_alignment();
  60 
  61    // There is a dependency on the name of the blob in src/share/vm/prims/jvmtiCodeBlobEvents.cpp
  62    // If changing the name, update the other file accordingly.
  63     BufferBlob* blob = BufferBlob::create("vtable chunks", bytes);
  64     if (blob == NULL) {
  65       return NULL;
  66     }
  67     _chunk = blob->content_begin();
  68     _chunk_end = _chunk + bytes;
  69     Forte::register_stub("vtable stub", _chunk, _chunk_end);
  70     align_chunk();
  71   }
  72   assert(_chunk + real_size <= _chunk_end, "bad allocation");
  73   void* res = _chunk;
  74   _chunk += real_size;
  75   align_chunk();
  76  return res;
  77 }
  78 
  79 
  80 void VtableStub::print_on(outputStream* st) const {
  81   st->print("vtable stub (index = %d, receiver_location = %d, code = [" INTPTR_FORMAT ", " INTPTR_FORMAT "[)",
  82              index(), receiver_location(), code_begin(), code_end());
  83 }
  84 
  85 
  86 // -----------------------------------------------------------------------------------------
  87 // Implementation of VtableStubs
  88 //
  89 // For each hash value there's a linked list of vtable stubs (with that
  90 // hash value). Each list is anchored in a little hash _table, indexed
  91 // by that hash value.
  92 
  93 VtableStub* VtableStubs::_table[VtableStubs::N];
  94 int VtableStubs::_number_of_vtable_stubs = 0;
  95 
  96 
  97 void VtableStubs::initialize() {
  98   VtableStub::_receiver_location = SharedRuntime::name_for_receiver();
  99   {
 100     MutexLocker ml(VtableStubs_lock);
 101     assert(_number_of_vtable_stubs == 0, "potential performance bug: VtableStubs initialized more than once");
 102     assert(is_power_of_2(N), "N must be a power of 2");
 103     for (int i = 0; i < N; i++) {
 104       _table[i] = NULL;
 105     }
 106   }
 107 }
 108 
 109 
 110 address VtableStubs::find_stub(bool is_vtable_stub, int vtable_index) {
 111   assert(vtable_index >= 0, "must be positive");
 112 
 113   VtableStub* s = ShareVtableStubs ? lookup(is_vtable_stub, vtable_index) : NULL;
 114   if (s == NULL) {
 115     if (is_vtable_stub) {
 116       s = create_vtable_stub(vtable_index);
 117     } else {
 118       s = create_itable_stub(vtable_index);
 119     }
 120 
 121     // Creation of vtable or itable can fail if there is not enough free space in the code cache.
 122     if (s == NULL) {
 123       return NULL;
 124     }
 125 
 126     enter(is_vtable_stub, vtable_index, s);
 127     if (PrintAdapterHandlers) {
 128       tty->print_cr("Decoding VtableStub %s[%d]@%d",
 129                     is_vtable_stub? "vtbl": "itbl", vtable_index, VtableStub::receiver_location());
 130       Disassembler::decode(s->code_begin(), s->code_end());
 131     }
 132     // Notify JVMTI about this stub. The event will be recorded by the enclosing
 133     // JvmtiDynamicCodeEventCollector and posted when this thread has released
 134     // all locks.
 135     if (JvmtiExport::should_post_dynamic_code_generated()) {
 136       JvmtiExport::post_dynamic_code_generated_while_holding_locks(is_vtable_stub? "vtable stub": "itable stub",
 137                                                                    s->code_begin(), s->code_end());
 138     }
 139   }
 140   return s->entry_point();
 141 }
 142 
 143 
 144 inline uint VtableStubs::hash(bool is_vtable_stub, int vtable_index){
 145   // Assumption: receiver_location < 4 in most cases.
 146   int hash = ((vtable_index << 2) ^ VtableStub::receiver_location()->value()) + vtable_index;
 147   return (is_vtable_stub ? ~hash : hash)  & mask;
 148 }
 149 
 150 
 151 VtableStub* VtableStubs::lookup(bool is_vtable_stub, int vtable_index) {
 152   MutexLocker ml(VtableStubs_lock);
 153   unsigned hash = VtableStubs::hash(is_vtable_stub, vtable_index);
 154   VtableStub* s = _table[hash];
 155   while( s && !s->matches(is_vtable_stub, vtable_index)) s = s->next();
 156   return s;
 157 }
 158 
 159 
 160 void VtableStubs::enter(bool is_vtable_stub, int vtable_index, VtableStub* s) {
 161   MutexLocker ml(VtableStubs_lock);
 162   assert(s->matches(is_vtable_stub, vtable_index), "bad vtable stub");
 163   unsigned int h = VtableStubs::hash(is_vtable_stub, vtable_index);
 164   // enter s at the beginning of the corresponding list
 165   s->set_next(_table[h]);
 166   _table[h] = s;
 167   _number_of_vtable_stubs++;
 168 }
 169 
 170 
 171 bool VtableStubs::is_entry_point(address pc) {
 172   MutexLocker ml(VtableStubs_lock);
 173   VtableStub* stub = (VtableStub*)(pc - VtableStub::entry_offset());
 174   uint hash = VtableStubs::hash(stub->is_vtable_stub(), stub->index());
 175   VtableStub* s;
 176   for (s = _table[hash]; s != NULL && s != stub; s = s->next()) {}
 177   return s == stub;
 178 }
 179 
 180 
 181 bool VtableStubs::contains(address pc) {
 182   // simple solution for now - we may want to use
 183   // a faster way if this function is called often
 184   return stub_containing(pc) != NULL;
 185 }
 186 
 187 
 188 VtableStub* VtableStubs::stub_containing(address pc) {
 189   // Note: No locking needed since any change to the data structure
 190   //       happens with an atomic store into it (we don't care about
 191   //       consistency with the _number_of_vtable_stubs counter).
 192   for (int i = 0; i < N; i++) {
 193     for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
 194       if (s->contains(pc)) return s;
 195     }
 196   }
 197   return NULL;
 198 }
 199 
 200 void vtableStubs_init() {
 201   VtableStubs::initialize();
 202 }
 203 
 204 void VtableStubs::vtable_stub_do(void f(VtableStub*)) {
 205     for (int i = 0; i < N; i++) {
 206         for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
 207             f(s);
 208         }
 209     }
 210 }
 211 
 212 
 213 //-----------------------------------------------------------------------------------------------------
 214 // Non-product code
 215 #ifndef PRODUCT
 216 
 217 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index) {
 218   ResourceMark rm;
 219   HandleMark hm;
 220   Klass* klass = receiver->klass();
 221   InstanceKlass* ik = InstanceKlass::cast(klass);
 222   klassVtable* vt = ik->vtable();
 223   ik->print();
 224   fatal(err_msg("bad compiled vtable dispatch: receiver " INTPTR_FORMAT ", "
 225                 "index %d (vtable length %d)",
 226                 (address)receiver, index, vt->length()));
 227 }
 228 
 229 #endif // Product