1 /* 2 * Copyright (c) 1999, 2019, 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 refes into the CP cache? 144 bool has_cache_index() const { return Bytecodes::uses_cp_cache(cur_bc_raw()); } 145 146 bool has_optional_appendix() { return Bytecodes::has_optional_appendix(cur_bc_raw()); } 147 148 int get_index_u1() const { 149 return bytecode().get_index_u1(cur_bc_raw()); 150 } 151 152 // Get a byte index following this bytecode. 153 // If prefixed with a wide bytecode, get a wide index. 154 int get_index() const { 155 assert(!has_cache_index(), "else use cpcache variant"); 156 return (_pc == _was_wide) // was widened? 157 ? get_index_u2(true) // yes, return wide index 158 : get_index_u1(); // no, return narrow index 159 } 160 161 // Get 2-byte index (byte swapping depending on which bytecode) 162 int get_index_u2(bool is_wide = false) const { 163 return bytecode().get_index_u2(cur_bc_raw(), is_wide); 164 } 165 166 // Get 2-byte index in native byte order. (Rewriter::rewrite makes these.) 167 int get_index_u2_cpcache() const { 168 return bytecode().get_index_u2_cpcache(cur_bc_raw()); 169 } 170 171 // Get 4-byte index, for invokedynamic. 172 int get_index_u4() const { 173 return bytecode().get_index_u4(cur_bc_raw()); 174 } 175 176 bool has_index_u4() const { 177 return bytecode().has_index_u4(cur_bc_raw()); 178 } 179 180 // Get dimensions byte (multinewarray) 181 int get_dimensions() const { return *(unsigned char*)(_pc-1); } 182 183 // Sign-extended index byte/short, no widening 184 int get_constant_u1() const { return bytecode().get_constant_u1(instruction_size()-1, cur_bc_raw()); } 185 int get_constant_u2(bool is_wide = false) const { return bytecode().get_constant_u2(instruction_size()-2, cur_bc_raw(), is_wide); } 186 187 // Get a byte signed constant for "iinc". Invalid for other bytecodes. 188 // If prefixed with a wide bytecode, get a wide constant 189 int get_iinc_con() const {return (_pc==_was_wide) ? (jshort) get_constant_u2(true) : (jbyte) get_constant_u1();} 190 191 // 2-byte branch offset from current pc 192 int get_dest() const { 193 return cur_bci() + bytecode().get_offset_s2(cur_bc_raw()); 194 } 195 196 // 2-byte branch offset from next pc 197 int next_get_dest() const { 198 assert(_pc < _end, ""); 199 return next_bci() + next_bytecode().get_offset_s2(Bytecodes::_ifeq); 200 } 201 202 // 4-byte branch offset from current pc 203 int get_far_dest() const { 204 return cur_bci() + bytecode().get_offset_s4(cur_bc_raw()); 205 } 206 207 // For a lookup or switch table, return target destination 208 int get_int_table( int index ) const { 209 return Bytes::get_Java_u4((address)&_table_base[index]); } 210 211 int get_dest_table( int index ) const { 212 return cur_bci() + get_int_table(index); } 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 bool is_klass_never_null() const; 225 226 // If this bytecode is one of the ldc variants, get the referenced 227 // constant. Do not attempt to resolve it, since that would require 228 // execution of Java code. If it is not resolved, return an unloaded 229 // object (ciConstant.as_object()->is_loaded() == false). 230 ciConstant get_constant(); 231 constantTag get_constant_pool_tag(int index) const; 232 233 // True if the klass-using bytecode points to an unresolved klass 234 bool is_unresolved_klass() const { 235 constantTag tag = get_constant_pool_tag(get_klass_index()); 236 return tag.is_unresolved_klass(); 237 } 238 239 // If this bytecode is one of get_field, get_static, put_field, 240 // or put_static, get the referenced field. 241 ciField* get_field(bool& will_link); 242 243 ciInstanceKlass* get_declared_field_holder(); 244 int get_field_holder_index(); 245 246 ciMethod* get_method(bool& will_link, ciSignature* *declared_signature_result); 247 bool has_appendix(); 248 ciObject* get_appendix(); 249 bool has_local_signature(); 250 ciKlass* get_declared_method_holder(); 251 int get_method_holder_index(); 252 int get_method_signature_index(const constantPoolHandle& cpool); 253 254 }; 255 256 257 // ciSignatureStream 258 // 259 // The class is used to iterate over the elements of a method signature. 260 class ciSignatureStream : public StackObj { 261 private: 262 ciSignature* _sig; 263 int _pos; 264 // holder is a method's holder 265 ciKlass* _holder; 266 public: 267 ciSignatureStream(ciSignature* signature, ciKlass* holder = NULL) { 268 _sig = signature; 269 _pos = 0; 270 _holder = holder; 271 } 272 273 bool at_return_type() { return _pos == _sig->count(); } 274 275 bool is_done() { return _pos > _sig->count(); } 276 277 void next() { 278 if (_pos <= _sig->count()) { 279 _pos++; 280 } 281 } 282 283 ciType* type() { 284 if (at_return_type()) { 285 return _sig->return_type(); 286 } else { 287 return _sig->type_at(_pos); 288 } 289 } 290 291 bool is_never_null() { 292 if (at_return_type()) { 293 return _sig->returns_never_null(); 294 } else { 295 return _sig->is_never_null_at(_pos); 296 } 297 } 298 299 // next klass in the signature 300 ciKlass* next_klass() { 301 ciKlass* sig_k; 302 if (_holder != NULL) { 303 sig_k = _holder; 304 _holder = NULL; 305 } else { 306 while (!type()->is_klass()) { 307 next(); 308 } 309 assert(!at_return_type(), "passed end of signature"); 310 sig_k = type()->as_klass(); 311 next(); 312 } 313 return sig_k; 314 } 315 }; 316 317 318 // ciExceptionHandlerStream 319 // 320 // The class is used to iterate over the exception handlers of 321 // a method. 322 class ciExceptionHandlerStream : public StackObj { 323 private: 324 // The method whose handlers we are traversing 325 ciMethod* _method; 326 327 // Our current position in the list of handlers 328 int _pos; 329 int _end; 330 331 ciInstanceKlass* _exception_klass; 332 int _bci; 333 bool _is_exact; 334 335 public: 336 ciExceptionHandlerStream(ciMethod* method) { 337 _method = method; 338 339 // Force loading of method code and handlers. 340 _method->code(); 341 342 _pos = 0; 343 _end = _method->_handler_count; 344 _exception_klass = NULL; 345 _bci = -1; 346 _is_exact = false; 347 } 348 349 ciExceptionHandlerStream(ciMethod* method, int bci, 350 ciInstanceKlass* exception_klass = NULL, 351 bool is_exact = false) { 352 _method = method; 353 354 // Force loading of method code and handlers. 355 _method->code(); 356 357 _pos = -1; 358 _end = _method->_handler_count + 1; // include the rethrow handler 359 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded() 360 ? exception_klass 361 : NULL); 362 _bci = bci; 363 assert(_bci >= 0, "bci out of range"); 364 _is_exact = is_exact; 365 next(); 366 } 367 368 // These methods are currently implemented in an odd way. 369 // Count the number of handlers the iterator has ever produced 370 // or will ever produce. Do not include the final rethrow handler. 371 // That is, a trivial exception handler stream will have a count 372 // of zero and produce just the rethrow handler. 373 int count(); 374 375 // Count the number of handlers this stream will produce from now on. 376 // Include the current handler, and the final rethrow handler. 377 // The remaining count will be zero iff is_done() is true, 378 int count_remaining(); 379 380 bool is_done() { 381 return (_pos >= _end); 382 } 383 384 void next() { 385 _pos++; 386 if (_bci != -1) { 387 // We are not iterating over all handlers... 388 while (!is_done()) { 389 ciExceptionHandler* handler = _method->_exception_handlers[_pos]; 390 if (handler->is_in_range(_bci)) { 391 if (handler->is_catch_all()) { 392 // Found final active catch block. 393 _end = _pos+1; 394 return; 395 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) { 396 // We cannot do any type analysis here. Must conservatively assume 397 // catch block is reachable. 398 return; 399 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) { 400 // This catch clause will definitely catch the exception. 401 // Final candidate. 402 _end = _pos+1; 403 return; 404 } else if (!_is_exact && 405 handler->catch_klass()->is_subtype_of(_exception_klass)) { 406 // This catch block may be reachable. 407 return; 408 } 409 } 410 411 // The catch block was not pertinent. Go on. 412 _pos++; 413 } 414 } else { 415 // This is an iteration over all handlers. 416 return; 417 } 418 } 419 420 ciExceptionHandler* handler() { 421 return _method->_exception_handlers[_pos]; 422 } 423 }; 424 425 426 427 // Implementation for declarations in bytecode.hpp 428 Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {} 429 Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 430 Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 431 432 #endif // SHARE_CI_CISTREAMS_HPP