ciStreams.hpp revision 3602:da91efe96a93
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. 41class ciBytecodeStream : StackObj { 42private: 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 82public: 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 ciKlass* get_declared_method_holder(); 264 int get_method_holder_index(); 265 int get_method_signature_index(); 266 267 // Get the resolved references arrays from the constant pool 268 ciObjArray* get_resolved_references(); 269}; 270 271 272// ciSignatureStream 273// 274// The class is used to iterate over the elements of a method signature. 275class ciSignatureStream : public StackObj { 276private: 277 ciSignature* _sig; 278 int _pos; 279public: 280 ciSignatureStream(ciSignature* signature) { 281 _sig = signature; 282 _pos = 0; 283 } 284 285 bool at_return_type() { return _pos == _sig->count(); } 286 287 bool is_done() { return _pos > _sig->count(); } 288 289 void next() { 290 if (_pos <= _sig->count()) { 291 _pos++; 292 } 293 } 294 295 ciType* type() { 296 if (at_return_type()) { 297 return _sig->return_type(); 298 } else { 299 return _sig->type_at(_pos); 300 } 301 } 302}; 303 304 305// ciExceptionHandlerStream 306// 307// The class is used to iterate over the exception handlers of 308// a method. 309class ciExceptionHandlerStream : public StackObj { 310private: 311 // The method whose handlers we are traversing 312 ciMethod* _method; 313 314 // Our current position in the list of handlers 315 int _pos; 316 int _end; 317 318 ciInstanceKlass* _exception_klass; 319 int _bci; 320 bool _is_exact; 321 322public: 323 ciExceptionHandlerStream(ciMethod* method) { 324 _method = method; 325 326 // Force loading of method code and handlers. 327 _method->code(); 328 329 _pos = 0; 330 _end = _method->_handler_count; 331 _exception_klass = NULL; 332 _bci = -1; 333 _is_exact = false; 334 } 335 336 ciExceptionHandlerStream(ciMethod* method, int bci, 337 ciInstanceKlass* exception_klass = NULL, 338 bool is_exact = false) { 339 _method = method; 340 341 // Force loading of method code and handlers. 342 _method->code(); 343 344 _pos = -1; 345 _end = _method->_handler_count + 1; // include the rethrow handler 346 _exception_klass = (exception_klass != NULL && exception_klass->is_loaded() 347 ? exception_klass 348 : NULL); 349 _bci = bci; 350 assert(_bci >= 0, "bci out of range"); 351 _is_exact = is_exact; 352 next(); 353 } 354 355 // These methods are currently implemented in an odd way. 356 // Count the number of handlers the iterator has ever produced 357 // or will ever produce. Do not include the final rethrow handler. 358 // That is, a trivial exception handler stream will have a count 359 // of zero and produce just the rethrow handler. 360 int count(); 361 362 // Count the number of handlers this stream will produce from now on. 363 // Include the current handler, and the final rethrow handler. 364 // The remaining count will be zero iff is_done() is true, 365 int count_remaining(); 366 367 bool is_done() { 368 return (_pos >= _end); 369 } 370 371 void next() { 372 _pos++; 373 if (_bci != -1) { 374 // We are not iterating over all handlers... 375 while (!is_done()) { 376 ciExceptionHandler* handler = _method->_exception_handlers[_pos]; 377 if (handler->is_in_range(_bci)) { 378 if (handler->is_catch_all()) { 379 // Found final active catch block. 380 _end = _pos+1; 381 return; 382 } else if (_exception_klass == NULL || !handler->catch_klass()->is_loaded()) { 383 // We cannot do any type analysis here. Must conservatively assume 384 // catch block is reachable. 385 return; 386 } else if (_exception_klass->is_subtype_of(handler->catch_klass())) { 387 // This catch clause will definitely catch the exception. 388 // Final candidate. 389 _end = _pos+1; 390 return; 391 } else if (!_is_exact && 392 handler->catch_klass()->is_subtype_of(_exception_klass)) { 393 // This catch block may be reachable. 394 return; 395 } 396 } 397 398 // The catch block was not pertinent. Go on. 399 _pos++; 400 } 401 } else { 402 // This is an iteration over all handlers. 403 return; 404 } 405 } 406 407 ciExceptionHandler* handler() { 408 return _method->_exception_handlers[_pos]; 409 } 410}; 411 412 413 414// Implementation for declarations in bytecode.hpp 415Bytecode::Bytecode(const ciBytecodeStream* stream, address bcp): _bcp(bcp != NULL ? bcp : stream->cur_bcp()), _code(Bytecodes::code_at(NULL, addr_at(0))) {} 416Bytecode_lookupswitch::Bytecode_lookupswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 417Bytecode_tableswitch::Bytecode_tableswitch(const ciBytecodeStream* stream): Bytecode(stream) { verify(); } 418 419#endif // SHARE_VM_CI_CISTREAMS_HPP 420