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1 /* |
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2 * Copyright 1998-2005 Sun Microsystems, Inc. All Rights Reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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20 * CA 95054 USA or visit www.sun.com if you need additional information or |
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21 * have any questions. |
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22 * |
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23 */ |
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24 |
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25 # include "incls/_precompiled.incl" |
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26 # include "incls/_rewriter.cpp.incl" |
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27 |
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28 |
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29 // Computes an index_map (new_index -> original_index) for contant pool entries |
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30 // that are referred to by the interpreter at runtime via the constant pool cache. |
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31 void Rewriter::compute_index_maps(constantPoolHandle pool, intArray*& index_map, intStack*& inverse_index_map) { |
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32 const int length = pool->length(); |
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33 index_map = new intArray(length, -1); |
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34 // Choose an initial value large enough that we don't get frequent |
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35 // calls to grow(). |
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36 inverse_index_map = new intStack(length / 2); |
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37 for (int i = 0; i < length; i++) { |
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38 switch (pool->tag_at(i).value()) { |
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39 case JVM_CONSTANT_Fieldref : // fall through |
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40 case JVM_CONSTANT_Methodref : // fall through |
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41 case JVM_CONSTANT_InterfaceMethodref: { |
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42 index_map->at_put(i, inverse_index_map->length()); |
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43 inverse_index_map->append(i); |
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44 } |
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45 } |
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46 } |
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47 } |
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48 |
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49 |
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50 // Creates a constant pool cache given an inverse_index_map |
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51 constantPoolCacheHandle Rewriter::new_constant_pool_cache(intArray& inverse_index_map, TRAPS) { |
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52 const int length = inverse_index_map.length(); |
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53 constantPoolCacheOop cache = oopFactory::new_constantPoolCache(length, CHECK_(constantPoolCacheHandle())); |
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54 cache->initialize(inverse_index_map); |
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55 return constantPoolCacheHandle(THREAD, cache); |
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56 } |
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57 |
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58 |
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59 |
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60 // The new finalization semantics says that registration of |
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61 // finalizable objects must be performed on successful return from the |
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62 // Object.<init> constructor. We could implement this trivially if |
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63 // <init> were never rewritten but since JVMTI allows this to occur, a |
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64 // more complicated solution is required. A special return bytecode |
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65 // is used only by Object.<init> to signal the finalization |
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66 // registration point. Additionally local 0 must be preserved so it's |
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67 // available to pass to the registration function. For simplicty we |
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68 // require that local 0 is never overwritten so it's available as an |
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69 // argument for registration. |
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70 |
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71 void Rewriter::rewrite_Object_init(methodHandle method, TRAPS) { |
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72 RawBytecodeStream bcs(method); |
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73 while (!bcs.is_last_bytecode()) { |
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74 Bytecodes::Code opcode = bcs.raw_next(); |
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75 switch (opcode) { |
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76 case Bytecodes::_return: *bcs.bcp() = Bytecodes::_return_register_finalizer; break; |
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77 |
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78 case Bytecodes::_istore: |
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79 case Bytecodes::_lstore: |
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80 case Bytecodes::_fstore: |
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81 case Bytecodes::_dstore: |
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82 case Bytecodes::_astore: |
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83 if (bcs.get_index() != 0) continue; |
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84 |
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85 // fall through |
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86 case Bytecodes::_istore_0: |
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87 case Bytecodes::_lstore_0: |
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88 case Bytecodes::_fstore_0: |
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89 case Bytecodes::_dstore_0: |
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90 case Bytecodes::_astore_0: |
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91 THROW_MSG(vmSymbols::java_lang_IncompatibleClassChangeError(), |
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92 "can't overwrite local 0 in Object.<init>"); |
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93 break; |
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94 } |
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95 } |
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96 } |
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97 |
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98 |
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99 // Rewrites a method given the index_map information |
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100 methodHandle Rewriter::rewrite_method(methodHandle method, intArray& index_map, TRAPS) { |
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101 |
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102 int nof_jsrs = 0; |
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103 bool has_monitor_bytecodes = false; |
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104 |
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105 { |
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106 // We cannot tolerate a GC in this block, because we've |
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107 // cached the bytecodes in 'code_base'. If the methodOop |
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108 // moves, the bytecodes will also move. |
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109 No_Safepoint_Verifier nsv; |
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110 Bytecodes::Code c; |
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111 |
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112 // Bytecodes and their length |
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113 const address code_base = method->code_base(); |
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114 const int code_length = method->code_size(); |
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115 |
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116 int bc_length; |
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117 for (int bci = 0; bci < code_length; bci += bc_length) { |
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118 address bcp = code_base + bci; |
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119 c = (Bytecodes::Code)(*bcp); |
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120 |
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121 // Since we have the code, see if we can get the length |
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122 // directly. Some more complicated bytecodes will report |
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123 // a length of zero, meaning we need to make another method |
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124 // call to calculate the length. |
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125 bc_length = Bytecodes::length_for(c); |
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126 if (bc_length == 0) { |
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127 bc_length = Bytecodes::length_at(bcp); |
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128 |
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129 // length_at will put us at the bytecode after the one modified |
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130 // by 'wide'. We don't currently examine any of the bytecodes |
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131 // modified by wide, but in case we do in the future... |
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132 if (c == Bytecodes::_wide) { |
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133 c = (Bytecodes::Code)bcp[1]; |
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134 } |
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135 } |
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136 |
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137 assert(bc_length != 0, "impossible bytecode length"); |
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138 |
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139 switch (c) { |
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140 case Bytecodes::_lookupswitch : { |
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141 #ifndef CC_INTERP |
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142 Bytecode_lookupswitch* bc = Bytecode_lookupswitch_at(bcp); |
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143 bc->set_code( |
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144 bc->number_of_pairs() < BinarySwitchThreshold |
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145 ? Bytecodes::_fast_linearswitch |
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146 : Bytecodes::_fast_binaryswitch |
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147 ); |
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148 #endif |
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149 break; |
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150 } |
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151 case Bytecodes::_getstatic : // fall through |
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152 case Bytecodes::_putstatic : // fall through |
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153 case Bytecodes::_getfield : // fall through |
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154 case Bytecodes::_putfield : // fall through |
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155 case Bytecodes::_invokevirtual : // fall through |
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156 case Bytecodes::_invokespecial : // fall through |
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157 case Bytecodes::_invokestatic : // fall through |
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158 case Bytecodes::_invokeinterface: { |
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159 address p = bcp + 1; |
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160 Bytes::put_native_u2(p, index_map[Bytes::get_Java_u2(p)]); |
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161 break; |
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162 } |
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163 case Bytecodes::_jsr : // fall through |
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164 case Bytecodes::_jsr_w : nof_jsrs++; break; |
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165 case Bytecodes::_monitorenter : // fall through |
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166 case Bytecodes::_monitorexit : has_monitor_bytecodes = true; break; |
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167 } |
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168 } |
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169 } |
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170 |
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171 // Update access flags |
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172 if (has_monitor_bytecodes) { |
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173 method->set_has_monitor_bytecodes(); |
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174 } |
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175 |
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176 // The present of a jsr bytecode implies that the method might potentially |
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177 // have to be rewritten, so we run the oopMapGenerator on the method |
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178 if (nof_jsrs > 0) { |
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179 method->set_has_jsrs(); |
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180 ResolveOopMapConflicts romc(method); |
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181 methodHandle original_method = method; |
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182 method = romc.do_potential_rewrite(CHECK_(methodHandle())); |
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183 if (method() != original_method()) { |
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184 // Insert invalid bytecode into original methodOop and set |
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185 // interpreter entrypoint, so that a executing this method |
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186 // will manifest itself in an easy recognizable form. |
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187 address bcp = original_method->bcp_from(0); |
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188 *bcp = (u1)Bytecodes::_shouldnotreachhere; |
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189 int kind = Interpreter::method_kind(original_method); |
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190 original_method->set_interpreter_kind(kind); |
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191 } |
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192 |
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193 // Update monitor matching info. |
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194 if (romc.monitor_safe()) { |
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195 method->set_guaranteed_monitor_matching(); |
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196 } |
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197 } |
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198 |
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199 // Setup method entrypoints for compiler and interpreter |
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200 method->link_method(method, CHECK_(methodHandle())); |
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201 |
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202 return method; |
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203 } |
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204 |
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205 |
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206 void Rewriter::rewrite(instanceKlassHandle klass, TRAPS) { |
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207 // gather starting points |
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208 ResourceMark rm(THREAD); |
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209 constantPoolHandle pool (THREAD, klass->constants()); |
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210 objArrayHandle methods (THREAD, klass->methods()); |
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211 assert(pool->cache() == NULL, "constant pool cache must not be set yet"); |
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212 |
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213 // determine index maps for methodOop rewriting |
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214 intArray* index_map = NULL; |
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215 intStack* inverse_index_map = NULL; |
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216 compute_index_maps(pool, index_map, inverse_index_map); |
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217 |
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218 // allocate constant pool cache |
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219 constantPoolCacheHandle cache = new_constant_pool_cache(*inverse_index_map, CHECK); |
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220 pool->set_cache(cache()); |
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221 cache->set_constant_pool(pool()); |
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222 |
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223 if (RegisterFinalizersAtInit && klass->name() == vmSymbols::java_lang_Object()) { |
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224 int i = methods->length(); |
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225 while (i-- > 0) { |
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226 methodOop method = (methodOop)methods->obj_at(i); |
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227 if (method->intrinsic_id() == vmIntrinsics::_Object_init) { |
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228 // rewrite the return bytecodes of Object.<init> to register the |
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229 // object for finalization if needed. |
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230 methodHandle m(THREAD, method); |
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231 rewrite_Object_init(m, CHECK); |
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232 break; |
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233 } |
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234 } |
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235 } |
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236 |
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237 // rewrite methods |
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238 { int i = methods->length(); |
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239 while (i-- > 0) { |
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240 methodHandle m(THREAD, (methodOop)methods->obj_at(i)); |
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241 m = rewrite_method(m, *index_map, CHECK); |
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242 // Method might have gotten rewritten. |
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243 methods->obj_at_put(i, m()); |
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244 } |
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245 } |
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246 } |