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(bool& will_link); 223 int get_klass_index() const; 224 225 // If this bytecode is one of the ldc variants, get the referenced 226 // constant. Do not attempt to resolve it, since that would require 227 // execution of Java code. If it is not resolved, return an unloaded 228 // object (ciConstant.as_object()->is_loaded() == false). 229 ciConstant get_constant(); 230 constantTag get_constant_pool_tag(int index) const; 231 BasicType get_basic_type_for_constant_at(int index) const; 232 233 constantTag get_raw_pool_tag(int index) const; 234 235 // True if the klass-using bytecode points to an unresolved klass 236 bool is_unresolved_klass() const { 237 constantTag tag = get_constant_pool_tag(get_klass_index()); 238 return tag.is_unresolved_klass(); 239 } 240 241 bool is_dynamic_constant() const { 242 assert(cur_bc() == Bytecodes::_ldc || 243 cur_bc() == Bytecodes::_ldc_w || 244 cur_bc() == Bytecodes::_ldc2_w, "not supported: %s", Bytecodes::name(cur_bc())); 245 246 int index = get_constant_pool_index(); 247 constantTag tag = get_raw_pool_tag(index); 248 return tag.is_dynamic_constant() || 249 tag.is_dynamic_constant_in_error(); 250 } 251 252 bool is_in_error() const { 253 assert(cur_bc() == Bytecodes::_ldc || 254 cur_bc() == Bytecodes::_ldc_w || 255 cur_bc() == Bytecodes::_ldc2_w, "not supported: %s", Bytecodes::name(cur_bc())); 256 257 int index = get_constant_pool_index(); 258 constantTag tag = get_constant_pool_tag(index); 259 return tag.is_unresolved_klass_in_error() || 260 tag.is_method_handle_in_error() || 261 tag.is_method_type_in_error() || 262 tag.is_dynamic_constant_in_error(); 263 } 264 265 // If this bytecode is one of get_field, get_static, put_field, 266 // or put_static, get the referenced field. 267 ciField* get_field(bool& will_link); 268 269 ciInstanceKlass* get_declared_field_holder(); 270 int get_field_holder_index(); 271 272 ciMethod* get_method(bool& will_link, ciSignature* *declared_signature_result); 273 bool has_appendix(); 274 ciObject* get_appendix(); 275 bool has_local_signature(); 276 ciKlass* get_declared_method_holder(); 277 int get_method_holder_index(); 278 int get_method_signature_index(const constantPoolHandle& cpool); 279 280 }; 281 282 283 // ciSignatureStream 284 // 285 // The class is used to iterate over the elements of a method signature. 286 class ciSignatureStream : public StackObj { 287 private: 288 ciSignature* _sig; 289 int _pos; 290 // holder is a method's holder 291 ciKlass* _holder; 292 public: 293 ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) { 294 _sig = signature; 295 _pos = 0; 296 _holder = holder; 297 } 298 299 bool at_return_type() { return _pos == _sig->count(); } 300 301 bool is_done() { return _pos > _sig->count(); } 302 303 void next() { 304 if (_pos <= _sig->count()) { 305 _pos++; 306 } 307 } 308 309 ciType* type() { 310 if (at_return_type()) { 311 return _sig->return_type(); 312 } else { 313 return _sig->type_at(_pos); 314 } 315 } 316 317 // next klass in the signature 318 ciKlass* next_klass() { 319 ciKlass* sig_k; 320 if (_holder != NULL) { 321 sig_k = _holder; 322 _holder = NULL; 323 } else { 324 while (!type()->is_klass()) { 325 next(); 326 } 327 assert(!at_return_type(), "passed end of signature"); 328 sig_k = type()->as_klass(); 329 next(); 330 } 331 return sig_k; 332 } 333 }; 334 335 336 // ciExceptionHandlerStream 337 // 338 // The class is used to iterate over the exception handlers of 339 // a method. 340 class ciExceptionHandlerStream : public StackObj { 341 private: 342 // The method whose handlers we are traversing 343 ciMethod* _method; 344 345 // Our current position in the list of handlers 346 int _pos; 347 int _end; 348 349 ciInstanceKlass* _exception_klass; 350 int _bci; 351 bool _is_exact; 352 353 public: 354 ciExceptionHandlerStream(ciMethod* method) { 355 _method = method; 356 357 // Force loading of method code and handlers. 358 _method->code(); 359 360 _pos = 0; 361 _end = _method->_handler_count; 362 _exception_klass = NULL; 363 _bci = -1; 364 _is_exact = false; 365 } 366 367 ciExceptionHandlerStream(ciMethod* method, int bci, 368 ciInstanceKlass* exception_klass = NULL, 369 bool is_exact = false) { 370 _method = method; 371 372 // Force loading of method code and handlers. 373 _method->code(); 374 375 _pos = -1; 376 _end = _method->_handler_count + 1; // include the rethrow handler 377 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded() 378 ? exception_klass 379 : NULL); 380 _bci = bci; 381 assert(_bci >= 0, "bci out of range"); 382 _is_exact = is_exact; 383 next(); 384 } 385 386 // These methods are currently implemented in an odd way. 387 // Count the number of handlers the iterator has ever produced 388 // or will ever produce. Do not include the final rethrow handler. 389 // That is, a trivial exception handler stream will have a count 390 // of zero and produce just the rethrow handler. 391 int count(); 392 393 // Count the number of handlers this stream will produce from now on. 394 // Include the current handler, and the final rethrow handler. 395 // The remaining count will be zero iff is_done() is true, 396 int count_remaining(); 397 398 bool is_done() { 399 return (_pos >= _end); 400 } 401 402 void next() { 403 _pos++; 404 if (_bci != -1) { 405 // We are not iterating over all handlers... 406 while (!is_done()) { 407 ciExceptionHandler* handler = _method->_exception_handlers[_pos]; 408 if (handler->is_in_range(_bci)) { 409 if (handler->is_catch_all()) { 410 // Found final active catch block. 411 _end = _pos+1; 412 return; 413 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) { 414 // We cannot do any type analysis here. Must conservatively assume 415 // catch block is reachable. 416 return; 417 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) { 418 // This catch clause will definitely catch the exception. 419 // Final candidate. 420 _end = _pos+1; 421 return; 422 } else if (!_is_exact && 423 handler->catch_klass()->is_subtype_of(_exception_klass)) { 424 // This catch block may be reachable. 425 return; 426 } 427 } 428 429 // The catch block was not pertinent. Go on. 430 _pos++; 431 } 432 } else { 433 // This is an iteration over all handlers. 434 return; 435 } 436 } 437 438 ciExceptionHandler* handler() { 439 return _method->_exception_handlers[_pos]; 440 } 441 }; 442 443 444 445 // Implementation for declarations in bytecode.hpp 446 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {} 447 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 448 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 449 450 #endif // SHARE_CI_CISTREAMS_HPP