1 /* 2 * Copyright (c) 1999, 2012, 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_CI_CISTREAMS_HPP 26 #define SHARE_VM_CI_CISTREAMS_HPP 27 28 #include "ci/ciClassList.hpp" 29 #include "ci/ciExceptionHandler.hpp" 30 #include "ci/ciInstanceKlass.hpp" 31 #include "ci/ciMethod.hpp" 32 #include "interpreter/bytecode.hpp" 33 34 // ciBytecodeStream 35 // 36 // The class is used to iterate over the bytecodes of a method. 37 // It hides the details of constant pool structure/access by 38 // providing accessors for constant pool items. It returns only pure 39 // Java bytecodes; VM-internal _fast bytecodes are translated back to 40 // their original form during iteration. 41 class ciBytecodeStream : StackObj { 42 private: 43 // Handling for the weird bytecodes 44 Bytecodes::Code next_wide_or_table(Bytecodes::Code); // Handle _wide & complicated inline table 45 46 static Bytecodes::Code check_java(Bytecodes::Code c) { 47 assert(Bytecodes::is_java_code(c), "should not return _fast bytecodes"); 48 return c; 49 } 50 51 static Bytecodes::Code check_defined(Bytecodes::Code c) { 52 assert(Bytecodes::is_defined(c), ""); 53 return c; 54 } 55 56 ciMethod* _method; // the method 57 ciInstanceKlass* _holder; 58 address _bc_start; // Start of current bytecode for table 59 address _was_wide; // Address past last wide bytecode 60 jint* _table_base; // Aligned start of last table or switch 61 62 address _start; // Start of bytecodes 63 address _end; // Past end of bytecodes 64 address _pc; // Current PC 65 Bytecodes::Code _bc; // Current bytecode 66 Bytecodes::Code _raw_bc; // Current bytecode, raw form 67 68 void reset( address base, unsigned int size ) { 69 _bc_start =_was_wide = 0; 70 _start = _pc = base; _end = base + size; 71 } 72 73 void assert_wide(bool require_wide) const { 74 if (require_wide) 75 { assert(is_wide(), "must be a wide instruction"); } 76 else { assert(!is_wide(), "must not be a wide instruction"); } 77 } 78 79 Bytecode bytecode() const { return Bytecode(this, _bc_start); } 80 Bytecode next_bytecode() const { return Bytecode(this, _pc); } 81 82 public: 83 // End-Of-Bytecodes 84 static Bytecodes::Code EOBC() { 85 return Bytecodes::_illegal; 86 } 87 88 ciBytecodeStream(ciMethod* m) { 89 reset_to_method(m); 90 } 91 92 ciBytecodeStream() { 93 reset_to_method(NULL); 94 } 95 96 ciMethod* method() const { return _method; } 97 98 void reset_to_method(ciMethod* m) { 99 _method = m; 100 if (m == NULL) { 101 _holder = NULL; 102 reset(NULL, 0); 103 } else { 104 _holder = m->holder(); 105 reset(m->code(), m->code_size()); 106 } 107 } 108 109 void reset_to_bci( int bci ); 110 111 // Force the iterator to report a certain bci. 112 void force_bci(int bci); 113 114 void set_max_bci( int max ) { 115 _end = _start + max; 116 } 117 118 address cur_bcp() const { return _bc_start; } // Returns bcp to current instruction 119 int next_bci() const { return _pc - _start; } 120 int cur_bci() const { return _bc_start - _start; } 121 int instruction_size() const { return _pc - _bc_start; } 122 123 Bytecodes::Code cur_bc() const{ return check_java(_bc); } 124 Bytecodes::Code cur_bc_raw() const { return check_defined(_raw_bc); } 125 Bytecodes::Code next_bc() { return Bytecodes::java_code((Bytecodes::Code)* _pc); } 126 127 // Return current ByteCode and increment PC to next bytecode, skipping all 128 // intermediate constants. Returns EOBC at end. 129 // Expected usage: 130 // ciBytecodeStream iter(m); 131 // while (iter.next() != ciBytecodeStream::EOBC()) { ... } 132 Bytecodes::Code next() { 133 _bc_start = _pc; // Capture start of bc 134 if( _pc >= _end ) return EOBC(); // End-Of-Bytecodes 135 136 // Fetch Java bytecode 137 // All rewritten bytecodes maintain the size of original bytecode. 138 _bc = Bytecodes::java_code(_raw_bc = (Bytecodes::Code)*_pc); 139 int csize = Bytecodes::length_for(_bc); // Expected size 140 _pc += csize; // Bump PC past bytecode 141 if (csize == 0) { 142 _bc = next_wide_or_table(_bc); 143 } 144 return check_java(_bc); 145 } 146 147 bool is_wide() const { return ( _pc == _was_wide ); } 148 149 // Does this instruction contain an index which refes into the CP cache? 150 bool has_cache_index() const { return Bytecodes::uses_cp_cache(cur_bc_raw()); } 151 152 bool has_optional_appendix() { return Bytecodes::has_optional_appendix(cur_bc_raw()); } 153 154 int get_index_u1() const { 155 return bytecode().get_index_u1(cur_bc_raw()); 156 } 157 158 int get_index_u1_cpcache() const { 159 return bytecode().get_index_u1_cpcache(cur_bc_raw()); 160 } 161 162 // Get a byte index following this bytecode. 163 // If prefixed with a wide bytecode, get a wide index. 164 int get_index() const { 165 assert(!has_cache_index(), "else use cpcache variant"); 166 return (_pc == _was_wide) // was widened? 167 ? get_index_u2(true) // yes, return wide index 168 : get_index_u1(); // no, return narrow index 169 } 170 171 // Get 2-byte index (byte swapping depending on which bytecode) 172 int get_index_u2(bool is_wide = false) const { 173 return bytecode().get_index_u2(cur_bc_raw(), is_wide); 174 } 175 176 // Get 2-byte index in native byte order. (Rewriter::rewrite makes these.) 177 int get_index_u2_cpcache() const { 178 return bytecode().get_index_u2_cpcache(cur_bc_raw()); 179 } 180 181 // Get 4-byte index, for invokedynamic. 182 int get_index_u4() const { 183 return bytecode().get_index_u4(cur_bc_raw()); 184 } 185 186 bool has_index_u4() const { 187 return bytecode().has_index_u4(cur_bc_raw()); 188 } 189 190 // Get dimensions byte (multinewarray) 191 int get_dimensions() const { return *(unsigned char*)(_pc-1); } 192 193 // Sign-extended index byte/short, no widening 194 int get_constant_u1() const { return bytecode().get_constant_u1(instruction_size()-1, cur_bc_raw()); } 195 int get_constant_u2(bool is_wide = false) const { return bytecode().get_constant_u2(instruction_size()-2, cur_bc_raw(), is_wide); } 196 197 // Get a byte signed constant for "iinc". Invalid for other bytecodes. 198 // If prefixed with a wide bytecode, get a wide constant 199 int get_iinc_con() const {return (_pc==_was_wide) ? (jshort) get_constant_u2(true) : (jbyte) get_constant_u1();} 200 201 // 2-byte branch offset from current pc 202 int get_dest() const { 203 return cur_bci() + bytecode().get_offset_s2(cur_bc_raw()); 204 } 205 206 // 2-byte branch offset from next pc 207 int next_get_dest() const { 208 assert(_pc < _end, ""); 209 return next_bci() + next_bytecode().get_offset_s2(Bytecodes::_ifeq); 210 } 211 212 // 4-byte branch offset from current pc 213 int get_far_dest() const { 214 return cur_bci() + bytecode().get_offset_s4(cur_bc_raw()); 215 } 216 217 // For a lookup or switch table, return target destination 218 int get_int_table( int index ) const { 219 return Bytes::get_Java_u4((address)&_table_base[index]); } 220 221 // For tableswitch - get length of offset part 222 int get_tableswitch_length() { return get_int_table(2)-get_int_table(1)+1; } 223 224 int get_dest_table( int index ) const { 225 return cur_bci() + get_int_table(index); } 226 227 // --- Constant pool access --- 228 int get_constant_raw_index() const; 229 int get_constant_pool_index() const; 230 int get_constant_cache_index() const; 231 int get_field_index(); 232 int get_method_index(); 233 234 // If this bytecode is a new, newarray, multianewarray, instanceof, 235 // or checkcast, get the referenced klass. 236 ciKlass* get_klass(bool& will_link); 237 int get_klass_index() const; 238 239 // If this bytecode is one of the ldc variants, get the referenced 240 // constant. Do not attempt to resolve it, since that would require 241 // execution of Java code. If it is not resolved, return an unloaded 242 // object (ciConstant.as_object()->is_loaded() == false). 243 ciConstant get_constant(); 244 constantTag get_constant_pool_tag(int index) const; 245 246 // True if the klass-using bytecode points to an unresolved klass 247 bool is_unresolved_klass() const { 248 constantTag tag = get_constant_pool_tag(get_klass_index()); 249 return tag.is_unresolved_klass(); 250 } 251 252 // If this bytecode is one of get_field, get_static, put_field, 253 // or put_static, get the referenced field. 254 ciField* get_field(bool& will_link); 255 256 ciInstanceKlass* get_declared_field_holder(); 257 int get_field_holder_index(); 258 int get_field_signature_index(); 259 260 ciMethod* get_method(bool& will_link, ciSignature* *declared_signature_result); 261 bool has_appendix(); 262 ciObject* get_appendix(); 263 bool has_method_type(); 264 ciMethodType* get_method_type(); 265 ciKlass* get_declared_method_holder(); 266 int get_method_holder_index(); 267 int get_method_signature_index(); 268 269 // Get the resolved references arrays from the constant pool 270 ciObjArray* get_resolved_references(); 271 }; 272 273 274 // ciSignatureStream 275 // 276 // The class is used to iterate over the elements of a method signature. 277 class ciSignatureStream : public StackObj { 278 private: 279 ciSignature* _sig; 280 int _pos; 281 // holder is a method's holder 282 ciKlass* _holder; 283 public: 284 ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) { 285 _sig = signature; 286 _pos = 0; 287 _holder = holder; 288 } 289 290 bool at_return_type() { return _pos == _sig->count(); } 291 292 bool is_done() { return _pos > _sig->count(); } 293 294 void next() { 295 if (_pos <= _sig->count()) { 296 _pos++; 297 } 298 } 299 300 ciType* type() { 301 if (at_return_type()) { 302 return _sig->return_type(); 303 } else { 304 return _sig->type_at(_pos); 305 } 306 } 307 308 // next klass in the signature 309 ciKlass* next_klass() { 310 ciKlass* sig_k; 311 if (_holder != NULL) { 312 sig_k = _holder; 313 _holder = NULL; 314 } else { 315 while (!type()->is_klass()) { 316 next(); 317 } 318 assert(!at_return_type(), "passed end of signature"); 319 sig_k = type()->as_klass(); 320 next(); 321 } 322 return sig_k; 323 } 324 }; 325 326 327 // ciExceptionHandlerStream 328 // 329 // The class is used to iterate over the exception handlers of 330 // a method. 331 class ciExceptionHandlerStream : public StackObj { 332 private: 333 // The method whose handlers we are traversing 334 ciMethod* _method; 335 336 // Our current position in the list of handlers 337 int _pos; 338 int _end; 339 340 ciInstanceKlass* _exception_klass; 341 int _bci; 342 bool _is_exact; 343 344 public: 345 ciExceptionHandlerStream(ciMethod* method) { 346 _method = method; 347 348 // Force loading of method code and handlers. 349 _method->code(); 350 351 _pos = 0; 352 _end = _method->_handler_count; 353 _exception_klass = NULL; 354 _bci = -1; 355 _is_exact = false; 356 } 357 358 ciExceptionHandlerStream(ciMethod* method, int bci, 359 ciInstanceKlass* exception_klass = NULL, 360 bool is_exact = false) { 361 _method = method; 362 363 // Force loading of method code and handlers. 364 _method->code(); 365 366 _pos = -1; 367 _end = _method->_handler_count + 1; // include the rethrow handler 368 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded() 369 ? exception_klass 370 : NULL); 371 _bci = bci; 372 assert(_bci >= 0, "bci out of range"); 373 _is_exact = is_exact; 374 next(); 375 } 376 377 // These methods are currently implemented in an odd way. 378 // Count the number of handlers the iterator has ever produced 379 // or will ever produce. Do not include the final rethrow handler. 380 // That is, a trivial exception handler stream will have a count 381 // of zero and produce just the rethrow handler. 382 int count(); 383 384 // Count the number of handlers this stream will produce from now on. 385 // Include the current handler, and the final rethrow handler. 386 // The remaining count will be zero iff is_done() is true, 387 int count_remaining(); 388 389 bool is_done() { 390 return (_pos >= _end); 391 } 392 393 void next() { 394 _pos++; 395 if (_bci != -1) { 396 // We are not iterating over all handlers... 397 while (!is_done()) { 398 ciExceptionHandler* handler = _method->_exception_handlers[_pos]; 399 if (handler->is_in_range(_bci)) { 400 if (handler->is_catch_all()) { 401 // Found final active catch block. 402 _end = _pos+1; 403 return; 404 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) { 405 // We cannot do any type analysis here. Must conservatively assume 406 // catch block is reachable. 407 return; 408 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) { 409 // This catch clause will definitely catch the exception. 410 // Final candidate. 411 _end = _pos+1; 412 return; 413 } else if (!_is_exact && 414 handler->catch_klass()->is_subtype_of(_exception_klass)) { 415 // This catch block may be reachable. 416 return; 417 } 418 } 419 420 // The catch block was not pertinent. Go on. 421 _pos++; 422 } 423 } else { 424 // This is an iteration over all handlers. 425 return; 426 } 427 } 428 429 ciExceptionHandler* handler() { 430 return _method->_exception_handlers[_pos]; 431 } 432 }; 433 434 435 436 // Implementation for declarations in bytecode.hpp 437 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {} 438 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 439 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 440 441 #endif // SHARE_VM_CI_CISTREAMS_HPP