1 /* 2 * Copyright (c) 1997, 2010, 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_BYTECODESTREAM_HPP 26 #define SHARE_VM_INTERPRETER_BYTECODESTREAM_HPP 27 28 #include "interpreter/bytecode.hpp" 29 #include "memory/allocation.hpp" 30 #include "oops/methodOop.hpp" 31 #ifdef TARGET_ARCH_x86 32 # include "bytes_x86.hpp" 33 #endif 34 #ifdef TARGET_ARCH_sparc 35 # include "bytes_sparc.hpp" 36 #endif 37 #ifdef TARGET_ARCH_zero 38 # include "bytes_zero.hpp" 39 #endif 40 41 // A BytecodeStream is used for fast iteration over the bytecodes 42 // of a methodOop. 43 // 44 // Usage: 45 // 46 // BytecodeStream s(method); 47 // Bytecodes::Code c; 48 // while ((c = s.next()) >= 0) { 49 // ... 50 // } 51 52 // A RawBytecodeStream is a simple version of BytecodeStream. 53 // It is used ONLY when we know the bytecodes haven't been rewritten 54 // yet, such as in the rewriter or the verifier. 55 56 // Here is the common base class for both RawBytecodeStream and BytecodeStream: 57 class BaseBytecodeStream: StackObj { 58 protected: 59 // stream buffer 60 methodHandle _method; // read from method directly 61 62 // reading position 63 int _bci; // bci if current bytecode 64 int _next_bci; // bci of next bytecode 65 int _end_bci; // bci after the current iteration interval 66 67 // last bytecode read 68 Bytecodes::Code _raw_code; 69 bool _is_wide; 70 bool _is_raw; // false in 'cooked' BytecodeStream 71 72 // Construction 73 BaseBytecodeStream(methodHandle method) : _method(method) { 74 set_interval(0, _method->code_size()); 75 _is_raw = false; 76 } 77 78 public: 79 // Iteration control 80 void set_interval(int beg_bci, int end_bci) { 81 // iterate over the interval [beg_bci, end_bci) 82 assert(0 <= beg_bci && beg_bci <= method()->code_size(), "illegal beg_bci"); 83 assert(0 <= end_bci && end_bci <= method()->code_size(), "illegal end_bci"); 84 // setup of iteration pointers 85 _bci = beg_bci; 86 _next_bci = beg_bci; 87 _end_bci = end_bci; 88 } 89 void set_start (int beg_bci) { 90 set_interval(beg_bci, _method->code_size()); 91 } 92 93 bool is_raw() const { return _is_raw; } 94 95 // Stream attributes 96 methodHandle method() const { return _method; } 97 98 int bci() const { return _bci; } 99 int next_bci() const { return _next_bci; } 100 int end_bci() const { return _end_bci; } 101 102 Bytecodes::Code raw_code() const { return _raw_code; } 103 bool is_wide() const { return _is_wide; } 104 int instruction_size() const { return (_next_bci - _bci); } 105 bool is_last_bytecode() const { return _next_bci >= _end_bci; } 106 107 address bcp() const { return method()->code_base() + _bci; } 108 Bytecode* bytecode() const { return Bytecode_at(bcp()); } 109 110 // State changes 111 void set_next_bci(int bci) { assert(0 <= bci && bci <= method()->code_size(), "illegal bci"); _next_bci = bci; } 112 113 // Bytecode-specific attributes 114 int dest() const { return bci() + bytecode()->get_offset_s2(raw_code()); } 115 int dest_w() const { return bci() + bytecode()->get_offset_s4(raw_code()); } 116 117 // One-byte indices. 118 int get_index_u1() const { assert_raw_index_size(1); return *(jubyte*)(bcp()+1); } 119 120 protected: 121 void assert_raw_index_size(int size) const NOT_DEBUG_RETURN; 122 void assert_raw_stream(bool want_raw) const NOT_DEBUG_RETURN; 123 }; 124 125 class RawBytecodeStream: public BaseBytecodeStream { 126 public: 127 // Construction 128 RawBytecodeStream(methodHandle method) : BaseBytecodeStream(method) { 129 _is_raw = true; 130 } 131 132 public: 133 // Iteration 134 // Use raw_next() rather than next() for faster method reference 135 Bytecodes::Code raw_next() { 136 Bytecodes::Code code; 137 // set reading position 138 _bci = _next_bci; 139 assert(!is_last_bytecode(), "caller should check is_last_bytecode()"); 140 141 address bcp = this->bcp(); 142 code = Bytecodes::code_or_bp_at(bcp); 143 144 // set next bytecode position 145 int l = Bytecodes::length_for(code); 146 if (l > 0 && (_bci + l) <= _end_bci) { 147 assert(code != Bytecodes::_wide && code != Bytecodes::_tableswitch 148 && code != Bytecodes::_lookupswitch, "can't be special bytecode"); 149 _is_wide = false; 150 _next_bci += l; 151 _raw_code = code; 152 return code; 153 } else { 154 return raw_next_special(code); 155 } 156 } 157 Bytecodes::Code raw_next_special(Bytecodes::Code code); 158 159 // Unsigned indices, widening, with no swapping of bytes 160 int get_index() const { return (is_wide()) ? get_index_u2_raw(bcp() + 2) : get_index_u1(); } 161 // Get an unsigned 2-byte index, with no swapping of bytes. 162 int get_index_u2() const { assert(!is_wide(), ""); return get_index_u2_raw(bcp() + 1); } 163 164 private: 165 int get_index_u2_raw(address p) const { 166 assert_raw_index_size(2); assert_raw_stream(true); 167 return Bytes::get_Java_u2(p); 168 } 169 }; 170 171 // In BytecodeStream, non-java bytecodes will be translated into the 172 // corresponding java bytecodes. 173 174 class BytecodeStream: public BaseBytecodeStream { 175 Bytecodes::Code _code; 176 177 public: 178 // Construction 179 BytecodeStream(methodHandle method) : BaseBytecodeStream(method) { } 180 181 // Iteration 182 Bytecodes::Code next() { 183 Bytecodes::Code raw_code, code; 184 // set reading position 185 _bci = _next_bci; 186 if (is_last_bytecode()) { 187 // indicate end of bytecode stream 188 raw_code = code = Bytecodes::_illegal; 189 } else { 190 // get bytecode 191 address bcp = this->bcp(); 192 raw_code = Bytecodes::code_at(bcp); 193 code = Bytecodes::java_code(raw_code); 194 // set next bytecode position 195 // 196 // note that we cannot advance before having the 197 // tty bytecode otherwise the stepping is wrong! 198 // (carefull: length_for(...) must be used first!) 199 int l = Bytecodes::length_for(code); 200 if (l == 0) l = Bytecodes::length_at(bcp); 201 _next_bci += l; 202 assert(_bci < _next_bci, "length must be > 0"); 203 // set attributes 204 _is_wide = false; 205 // check for special (uncommon) cases 206 if (code == Bytecodes::_wide) { 207 raw_code = (Bytecodes::Code)bcp[1]; 208 code = raw_code; // wide BCs are always Java-normal 209 _is_wide = true; 210 } 211 assert(Bytecodes::is_java_code(code), "sanity check"); 212 } 213 _raw_code = raw_code; 214 _code = code; 215 return _code; 216 } 217 218 bool is_active_breakpoint() const { return Bytecodes::is_active_breakpoint_at(bcp()); } 219 Bytecodes::Code code() const { return _code; } 220 221 // Unsigned indices, widening 222 int get_index() const { return is_wide() ? bytecode()->get_index_u2(raw_code(), true) : get_index_u1(); } 223 // Get an unsigned 2-byte index, swapping the bytes if necessary. 224 int get_index_u2() const { assert_raw_stream(false); 225 return bytecode()->get_index_u2(raw_code(), false); } 226 // Get an unsigned 2-byte index in native order. 227 int get_index_u2_cpcache() const { assert_raw_stream(false); 228 return bytecode()->get_index_u2_cpcache(raw_code()); } 229 int get_index_u4() const { assert_raw_stream(false); 230 return bytecode()->get_index_u4(raw_code()); } 231 bool has_index_u4() const { return bytecode()->has_index_u4(raw_code()); } 232 }; 233 234 #endif // SHARE_VM_INTERPRETER_BYTECODESTREAM_HPP