1 /* 2 * Copyright (c) 1999, 2021, 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_CI_CISTREAMS_HPP 26 #define SHARE_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 Bytecode bytecode() const { return Bytecode(this, _bc_start); } 74 Bytecode next_bytecode() const { return Bytecode(this, _pc); } 75 76 public: 77 // End-Of-Bytecodes 78 static Bytecodes::Code EOBC() { 79 return Bytecodes::_illegal; 80 } 81 82 ciBytecodeStream(ciMethod* m) { 83 reset_to_method(m); 84 } 85 86 ciBytecodeStream() { 87 reset_to_method(NULL); 88 } 89 90 ciMethod* method() const { return _method; } 91 92 void reset_to_method(ciMethod* m) { 93 _method = m; 94 if (m == NULL) { 95 _holder = NULL; 96 reset(NULL, 0); 97 } else { 98 _holder = m->holder(); 99 reset(m->code(), m->code_size()); 100 } 101 } 102 103 void reset_to_bci( int bci ); 104 105 // Force the iterator to report a certain bci. 106 void force_bci(int bci); 107 108 void set_max_bci( int max ) { 109 _end = _start + max; 110 } 111 112 address cur_bcp() const { return _bc_start; } // Returns bcp to current instruction 113 int next_bci() const { return _pc - _start; } 114 int cur_bci() const { return _bc_start - _start; } 115 int instruction_size() const { return _pc - _bc_start; } 116 117 Bytecodes::Code cur_bc() const{ return check_java(_bc); } 118 Bytecodes::Code cur_bc_raw() const { return check_defined(_raw_bc); } 119 Bytecodes::Code next_bc() { return Bytecodes::java_code((Bytecodes::Code)* _pc); } 120 121 // Return current ByteCode and increment PC to next bytecode, skipping all 122 // intermediate constants. Returns EOBC at end. 123 // Expected usage: 124 // ciBytecodeStream iter(m); 125 // while (iter.next() != ciBytecodeStream::EOBC()) { ... } 126 Bytecodes::Code next() { 127 _bc_start = _pc; // Capture start of bc 128 if( _pc >= _end ) return EOBC(); // End-Of-Bytecodes 129 130 // Fetch Java bytecode 131 // All rewritten bytecodes maintain the size of original bytecode. 132 _bc = Bytecodes::java_code(_raw_bc = (Bytecodes::Code)*_pc); 133 int csize = Bytecodes::length_for(_bc); // Expected size 134 _pc += csize; // Bump PC past bytecode 135 if (csize == 0) { 136 _bc = next_wide_or_table(_bc); 137 } 138 return check_java(_bc); 139 } 140 141 bool is_wide() const { return ( _pc == _was_wide ); } 142 143 // Does this instruction contain an index which refers into the CP cache? 144 bool has_cache_index() const { return Bytecodes::uses_cp_cache(cur_bc_raw()); } 145 146 int get_index_u1() const { 147 return bytecode().get_index_u1(cur_bc_raw()); 148 } 149 150 // Get a byte index following this bytecode. 151 // If prefixed with a wide bytecode, get a wide index. 152 int get_index() const { 153 assert(!has_cache_index(), "else use cpcache variant"); 154 return (_pc == _was_wide) // was widened? 155 ? get_index_u2(true) // yes, return wide index 156 : get_index_u1(); // no, return narrow index 157 } 158 159 // Get 2-byte index (byte swapping depending on which bytecode) 160 int get_index_u2(bool is_wide = false) const { 161 return bytecode().get_index_u2(cur_bc_raw(), is_wide); 162 } 163 164 // Get 2-byte index in native byte order. (Rewriter::rewrite makes these.) 165 int get_index_u2_cpcache() const { 166 return bytecode().get_index_u2_cpcache(cur_bc_raw()); 167 } 168 169 // Get 4-byte index, for invokedynamic. 170 int get_index_u4() const { 171 return bytecode().get_index_u4(cur_bc_raw()); 172 } 173 174 bool has_index_u4() const { 175 return bytecode().has_index_u4(cur_bc_raw()); 176 } 177 178 // Get dimensions byte (multinewarray) 179 int get_dimensions() const { return *(unsigned char*)(_pc-1); } 180 181 // Sign-extended index byte/short, no widening 182 int get_constant_u1() const { return bytecode().get_constant_u1(instruction_size()-1, cur_bc_raw()); } 183 int get_constant_u2(bool is_wide = false) const { return bytecode().get_constant_u2(instruction_size()-2, cur_bc_raw(), is_wide); } 184 185 // Get a byte signed constant for "iinc". Invalid for other bytecodes. 186 // If prefixed with a wide bytecode, get a wide constant 187 int get_iinc_con() const {return (_pc==_was_wide) ? (jshort) get_constant_u2(true) : (jbyte) get_constant_u1();} 188 189 // 2-byte branch offset from current pc 190 int get_dest() const { 191 return cur_bci() + bytecode().get_offset_s2(cur_bc_raw()); 192 } 193 194 // 2-byte branch offset from next pc 195 int next_get_dest() const { 196 assert(_pc < _end, ""); 197 return next_bci() + next_bytecode().get_offset_s2(Bytecodes::_ifeq); 198 } 199 200 // 4-byte branch offset from current pc 201 int get_far_dest() const { 202 return cur_bci() + bytecode().get_offset_s4(cur_bc_raw()); 203 } 204 205 // For a lookup or switch table, return target destination 206 jint get_int_table( int index ) const { 207 return (jint)Bytes::get_Java_u4((address)&_table_base[index]); 208 } 209 210 int get_dest_table( int index ) const { 211 return cur_bci() + get_int_table(index); 212 } 213 214 // --- Constant pool access --- 215 int get_constant_raw_index() const; 216 int get_constant_pool_index() const; 217 int get_field_index(); 218 int get_method_index(); 219 220 // If this bytecode is a new, newarray, multianewarray, instanceof, 221 // or checkcast, get the referenced klass. 222 ciKlass* get_klass(); 223 ciKlass* get_klass(bool& will_link); 224 int get_klass_index() const; 225 bool has_Q_signature() const; 226 227 // If this bytecode is one of the ldc variants, get the referenced 228 // constant. Do not attempt to resolve it, since that would require 229 // execution of Java code. If it is not resolved, return an unloaded 230 // object (ciConstant.as_object()->is_loaded() == false). 231 ciConstant get_constant(); 232 constantTag get_constant_pool_tag(int index) const; 233 BasicType get_basic_type_for_constant_at(int index) const; 234 235 constantTag get_raw_pool_tag_at(int index) const; 236 237 constantTag get_raw_pool_tag() const { 238 int index = get_constant_pool_index(); 239 return get_raw_pool_tag_at(index); 240 } 241 242 // True if the klass-using bytecode points to an unresolved klass 243 bool is_unresolved_klass() const { 244 constantTag tag = get_constant_pool_tag(get_klass_index()); 245 return tag.is_unresolved_klass(); 246 } 247 248 bool is_dynamic_constant() const { 249 assert(cur_bc() == Bytecodes::_ldc || 250 cur_bc() == Bytecodes::_ldc_w || 251 cur_bc() == Bytecodes::_ldc2_w, "not supported: %s", Bytecodes::name(cur_bc())); 252 253 constantTag tag = get_raw_pool_tag(); 254 return tag.is_dynamic_constant() || 255 tag.is_dynamic_constant_in_error(); 256 } 257 258 bool is_string_constant() const { 259 assert(cur_bc() == Bytecodes::_ldc || 260 cur_bc() == Bytecodes::_ldc_w || 261 cur_bc() == Bytecodes::_ldc2_w, "not supported: %s", Bytecodes::name(cur_bc())); 262 263 constantTag tag = get_raw_pool_tag(); 264 return tag.is_string(); 265 } 266 267 bool is_in_error() const { 268 assert(cur_bc() == Bytecodes::_ldc || 269 cur_bc() == Bytecodes::_ldc_w || 270 cur_bc() == Bytecodes::_ldc2_w, "not supported: %s", Bytecodes::name(cur_bc())); 271 272 int index = get_constant_pool_index(); 273 constantTag tag = get_constant_pool_tag(index); 274 return tag.is_unresolved_klass_in_error() || 275 tag.is_method_handle_in_error() || 276 tag.is_method_type_in_error() || 277 tag.is_dynamic_constant_in_error(); 278 } 279 280 // If this bytecode is one of get_field, get_static, put_field, 281 // or put_static, get the referenced field. 282 ciField* get_field(bool& will_link); 283 284 ciInstanceKlass* get_declared_field_holder(); 285 int get_field_holder_index(); 286 287 ciMethod* get_method(bool& will_link, ciSignature* *declared_signature_result); 288 bool has_appendix(); 289 ciObject* get_appendix(); 290 bool has_local_signature(); 291 ciKlass* get_declared_method_holder(); 292 int get_method_holder_index(); 293 int get_method_signature_index(const constantPoolHandle& cpool); 294 295 }; 296 297 298 // ciSignatureStream 299 // 300 // The class is used to iterate over the elements of a method signature. 301 class ciSignatureStream : public StackObj { 302 private: 303 ciSignature* _sig; 304 int _pos; 305 // holder is a method's holder 306 ciKlass* _holder; 307 public: 308 ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) { 309 _sig = signature; 310 _pos = 0; 311 _holder = holder; 312 } 313 314 bool at_return_type() { return _pos == _sig->count(); } 315 316 bool is_done() { return _pos > _sig->count(); } 317 318 void next() { 319 if (_pos <= _sig->count()) { 320 _pos++; 321 } 322 } 323 324 ciType* type() { 325 if (at_return_type()) { 326 return _sig->return_type(); 327 } else { 328 return _sig->type_at(_pos); 329 } 330 } 331 332 bool is_null_free() { 333 if (at_return_type()) { 334 return _sig->returns_null_free_inline_type(); 335 } else { 336 return _sig->is_null_free_at(_pos); 337 } 338 } 339 340 // next klass in the signature 341 ciKlass* next_klass() { 342 ciKlass* sig_k; 343 if (_holder != NULL) { 344 sig_k = _holder; 345 _holder = NULL; 346 } else { 347 while (!type()->is_klass()) { 348 next(); 349 } 350 assert(!at_return_type(), "passed end of signature"); 351 sig_k = type()->as_klass(); 352 next(); 353 } 354 return sig_k; 355 } 356 }; 357 358 359 // ciExceptionHandlerStream 360 // 361 // The class is used to iterate over the exception handlers of 362 // a method. 363 class ciExceptionHandlerStream : public StackObj { 364 private: 365 // The method whose handlers we are traversing 366 ciMethod* _method; 367 368 // Our current position in the list of handlers 369 int _pos; 370 int _end; 371 372 ciInstanceKlass* _exception_klass; 373 int _bci; 374 bool _is_exact; 375 376 public: 377 ciExceptionHandlerStream(ciMethod* method) { 378 _method = method; 379 380 // Force loading of method code and handlers. 381 _method->code(); 382 383 _pos = 0; 384 _end = _method->_handler_count; 385 _exception_klass = NULL; 386 _bci = -1; 387 _is_exact = false; 388 } 389 390 ciExceptionHandlerStream(ciMethod* method, int bci, 391 ciInstanceKlass* exception_klass = NULL, 392 bool is_exact = false) { 393 _method = method; 394 395 // Force loading of method code and handlers. 396 _method->code(); 397 398 _pos = -1; 399 _end = _method->_handler_count + 1; // include the rethrow handler 400 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded() 401 ? exception_klass 402 : NULL); 403 _bci = bci; 404 assert(_bci >= 0, "bci out of range"); 405 _is_exact = is_exact; 406 next(); 407 } 408 409 // These methods are currently implemented in an odd way. 410 // Count the number of handlers the iterator has ever produced 411 // or will ever produce. Do not include the final rethrow handler. 412 // That is, a trivial exception handler stream will have a count 413 // of zero and produce just the rethrow handler. 414 int count(); 415 416 // Count the number of handlers this stream will produce from now on. 417 // Include the current handler, and the final rethrow handler. 418 // The remaining count will be zero iff is_done() is true, 419 int count_remaining(); 420 421 bool is_done() { 422 return (_pos >= _end); 423 } 424 425 void next() { 426 _pos++; 427 if (_bci != -1) { 428 // We are not iterating over all handlers... 429 while (!is_done()) { 430 ciExceptionHandler* handler = _method->_exception_handlers[_pos]; 431 if (handler->is_in_range(_bci)) { 432 if (handler->is_catch_all()) { 433 // Found final active catch block. 434 _end = _pos+1; 435 return; 436 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) { 437 // We cannot do any type analysis here. Must conservatively assume 438 // catch block is reachable. 439 return; 440 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) { 441 // This catch clause will definitely catch the exception. 442 // Final candidate. 443 _end = _pos+1; 444 return; 445 } else if (!_is_exact && 446 handler->catch_klass()->is_subtype_of(_exception_klass)) { 447 // This catch block may be reachable. 448 return; 449 } 450 } 451 452 // The catch block was not pertinent. Go on. 453 _pos++; 454 } 455 } else { 456 // This is an iteration over all handlers. 457 return; 458 } 459 } 460 461 ciExceptionHandler* handler() { 462 return _method->_exception_handlers[_pos]; 463 } 464 }; 465 466 467 468 // Implementation for declarations in bytecode.hpp 469 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {} 470 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 471 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 472 473 #endif // SHARE_CI_CISTREAMS_HPP