| File: | jdk/src/hotspot/share/ci/ciMethodBlocks.cpp |
| Warning: | line 189, column 13 Value stored to 'dest' is never read |
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| 1 | /* |
| 2 | * Copyright (c) 2006, 2017, 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 | #include "precompiled.hpp" |
| 26 | #include "ci/ciMethodBlocks.hpp" |
| 27 | #include "ci/ciStreams.hpp" |
| 28 | #include "interpreter/bytecode.hpp" |
| 29 | #include "utilities/copy.hpp" |
| 30 | |
| 31 | // ciMethodBlocks |
| 32 | |
| 33 | |
| 34 | |
| 35 | ciBlock *ciMethodBlocks::block_containing(int bci) { |
| 36 | ciBlock *blk = _bci_to_block[bci]; |
| 37 | return blk; |
| 38 | } |
| 39 | |
| 40 | bool ciMethodBlocks::is_block_start(int bci) { |
| 41 | assert(bci >=0 && bci < _code_size, "valid bytecode range")do { if (!(bci >=0 && bci < _code_size)) { (*g_assert_poison ) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/ci/ciMethodBlocks.cpp" , 41, "assert(" "bci >=0 && bci < _code_size" ") failed" , "valid bytecode range"); ::breakpoint(); } } while (0); |
| 42 | ciBlock *b = _bci_to_block[bci]; |
| 43 | assert(b != NULL, "must have block for bytecode")do { if (!(b != __null)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/ci/ciMethodBlocks.cpp" , 43, "assert(" "b != __null" ") failed", "must have block for bytecode" ); ::breakpoint(); } } while (0); |
| 44 | return b->start_bci() == bci; |
| 45 | } |
| 46 | |
| 47 | // ------------------------------------------------------------------ |
| 48 | // ciMethodBlocks::split_block_at |
| 49 | // |
| 50 | // Split the block spanning bci into two separate ranges. The former |
| 51 | // block becomes the second half and a new range is created for the |
| 52 | // first half. Returns the range beginning at bci. |
| 53 | ciBlock *ciMethodBlocks::split_block_at(int bci) { |
| 54 | ciBlock *former_block = block_containing(bci); |
| 55 | ciBlock *new_block = new(_arena) ciBlock(_method, _num_blocks++, former_block->start_bci()); |
| 56 | _blocks->append(new_block); |
| 57 | assert(former_block != NULL, "must not be NULL")do { if (!(former_block != __null)) { (*g_assert_poison) = 'X' ;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/ci/ciMethodBlocks.cpp" , 57, "assert(" "former_block != __null" ") failed", "must not be NULL" ); ::breakpoint(); } } while (0); |
| 58 | new_block->set_limit_bci(bci); |
| 59 | former_block->set_start_bci(bci); |
| 60 | for (int pos=bci-1; pos >= 0; pos--) { |
| 61 | ciBlock *current_block = block_containing(pos); |
| 62 | if (current_block == former_block) { |
| 63 | // Replace it. |
| 64 | _bci_to_block[pos] = new_block; |
| 65 | } else if (current_block == NULL__null) { |
| 66 | // Non-bytecode start. Skip. |
| 67 | continue; |
| 68 | } else { |
| 69 | // We are done with our backwards walk |
| 70 | break; |
| 71 | } |
| 72 | } |
| 73 | // Move an exception handler information if needed. |
| 74 | if (former_block->is_handler()) { |
| 75 | int ex_start = former_block->ex_start_bci(); |
| 76 | int ex_end = former_block->ex_limit_bci(); |
| 77 | new_block->set_exception_range(ex_start, ex_end); |
| 78 | // Clear information in former_block. |
| 79 | former_block->clear_exception_handler(); |
| 80 | } |
| 81 | return former_block; |
| 82 | } |
| 83 | |
| 84 | ciBlock *ciMethodBlocks::make_block_at(int bci) { |
| 85 | ciBlock *cb = block_containing(bci); |
| 86 | if (cb == NULL__null ) { |
| 87 | // This is our first time visiting this bytecode. Create |
| 88 | // a fresh block and assign it this starting point. |
| 89 | ciBlock *nb = new(_arena) ciBlock(_method, _num_blocks++, bci); |
| 90 | _blocks->append(nb); |
| 91 | _bci_to_block[bci] = nb; |
| 92 | return nb; |
| 93 | } else if (cb->start_bci() == bci) { |
| 94 | // The block begins at bci. Simply return it. |
| 95 | return cb; |
| 96 | } else { |
| 97 | // We have already created a block containing bci but |
| 98 | // not starting at bci. This existing block needs to |
| 99 | // be split into two. |
| 100 | return split_block_at(bci); |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | ciBlock *ciMethodBlocks::make_dummy_block() { |
| 105 | ciBlock *dum = new(_arena) ciBlock(_method, -1, 0); |
| 106 | return dum; |
| 107 | } |
| 108 | |
| 109 | void ciMethodBlocks::do_analysis() { |
| 110 | ciBytecodeStream s(_method); |
| 111 | ciBlock *cur_block = block_containing(0); |
| 112 | int limit_bci = _method->code_size(); |
| 113 | |
| 114 | while (s.next() != ciBytecodeStream::EOBC()) { |
| 115 | int bci = s.cur_bci(); |
| 116 | // Determine if a new block has been made at the current bci. If |
| 117 | // this block differs from our current range, switch to the new |
| 118 | // one and end the old one. |
| 119 | assert(cur_block != NULL, "must always have a current block")do { if (!(cur_block != __null)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/ci/ciMethodBlocks.cpp" , 119, "assert(" "cur_block != __null" ") failed", "must always have a current block" ); ::breakpoint(); } } while (0); |
| 120 | ciBlock *new_block = block_containing(bci); |
| 121 | if (new_block == NULL__null || new_block == cur_block) { |
| 122 | // We have not marked this bci as the start of a new block. |
| 123 | // Keep interpreting the current_range. |
| 124 | _bci_to_block[bci] = cur_block; |
| 125 | } else { |
| 126 | cur_block->set_limit_bci(bci); |
| 127 | cur_block = new_block; |
| 128 | } |
| 129 | |
| 130 | switch (s.cur_bc()) { |
| 131 | case Bytecodes::_ifeq : |
| 132 | case Bytecodes::_ifne : |
| 133 | case Bytecodes::_iflt : |
| 134 | case Bytecodes::_ifge : |
| 135 | case Bytecodes::_ifgt : |
| 136 | case Bytecodes::_ifle : |
| 137 | case Bytecodes::_if_icmpeq : |
| 138 | case Bytecodes::_if_icmpne : |
| 139 | case Bytecodes::_if_icmplt : |
| 140 | case Bytecodes::_if_icmpge : |
| 141 | case Bytecodes::_if_icmpgt : |
| 142 | case Bytecodes::_if_icmple : |
| 143 | case Bytecodes::_if_acmpeq : |
| 144 | case Bytecodes::_if_acmpne : |
| 145 | case Bytecodes::_ifnull : |
| 146 | case Bytecodes::_ifnonnull : |
| 147 | { |
| 148 | cur_block->set_control_bci(bci); |
| 149 | ciBlock *fall_through = make_block_at(s.next_bci()); |
| 150 | int dest_bci = s.get_dest(); |
| 151 | ciBlock *dest = make_block_at(dest_bci); |
| 152 | break; |
| 153 | } |
| 154 | |
| 155 | case Bytecodes::_goto : |
| 156 | { |
| 157 | cur_block->set_control_bci(bci); |
| 158 | if (s.next_bci() < limit_bci) { |
| 159 | (void) make_block_at(s.next_bci()); |
| 160 | } |
| 161 | int dest_bci = s.get_dest(); |
| 162 | ciBlock *dest = make_block_at(dest_bci); |
| 163 | break; |
| 164 | } |
| 165 | |
| 166 | case Bytecodes::_jsr : |
| 167 | { |
| 168 | cur_block->set_control_bci(bci); |
| 169 | ciBlock *ret = make_block_at(s.next_bci()); |
| 170 | int dest_bci = s.get_dest(); |
| 171 | ciBlock *dest = make_block_at(dest_bci); |
| 172 | break; |
| 173 | } |
| 174 | |
| 175 | case Bytecodes::_tableswitch : |
| 176 | { |
| 177 | cur_block->set_control_bci(bci); |
| 178 | Bytecode_tableswitch sw(&s); |
| 179 | int len = sw.length(); |
| 180 | ciBlock *dest; |
| 181 | int dest_bci; |
| 182 | for (int i = 0; i < len; i++) { |
| 183 | dest_bci = s.cur_bci() + sw.dest_offset_at(i); |
| 184 | dest = make_block_at(dest_bci); |
| 185 | } |
| 186 | dest_bci = s.cur_bci() + sw.default_offset(); |
| 187 | make_block_at(dest_bci); |
| 188 | if (s.next_bci() < limit_bci) { |
| 189 | dest = make_block_at(s.next_bci()); |
Value stored to 'dest' is never read | |
| 190 | } |
| 191 | } |
| 192 | break; |
| 193 | |
| 194 | case Bytecodes::_lookupswitch: |
| 195 | { |
| 196 | cur_block->set_control_bci(bci); |
| 197 | Bytecode_lookupswitch sw(&s); |
| 198 | int len = sw.number_of_pairs(); |
| 199 | ciBlock *dest; |
| 200 | int dest_bci; |
| 201 | for (int i = 0; i < len; i++) { |
| 202 | dest_bci = s.cur_bci() + sw.pair_at(i).offset(); |
| 203 | dest = make_block_at(dest_bci); |
| 204 | } |
| 205 | dest_bci = s.cur_bci() + sw.default_offset(); |
| 206 | dest = make_block_at(dest_bci); |
| 207 | if (s.next_bci() < limit_bci) { |
| 208 | dest = make_block_at(s.next_bci()); |
| 209 | } |
| 210 | } |
| 211 | break; |
| 212 | |
| 213 | case Bytecodes::_goto_w : |
| 214 | { |
| 215 | cur_block->set_control_bci(bci); |
| 216 | if (s.next_bci() < limit_bci) { |
| 217 | (void) make_block_at(s.next_bci()); |
| 218 | } |
| 219 | int dest_bci = s.get_far_dest(); |
| 220 | ciBlock *dest = make_block_at(dest_bci); |
| 221 | break; |
| 222 | } |
| 223 | |
| 224 | case Bytecodes::_jsr_w : |
| 225 | { |
| 226 | cur_block->set_control_bci(bci); |
| 227 | ciBlock *ret = make_block_at(s.next_bci()); |
| 228 | int dest_bci = s.get_far_dest(); |
| 229 | ciBlock *dest = make_block_at(dest_bci); |
| 230 | break; |
| 231 | } |
| 232 | |
| 233 | case Bytecodes::_athrow : |
| 234 | cur_block->set_may_throw(); |
| 235 | // fall-through |
| 236 | case Bytecodes::_ret : |
| 237 | case Bytecodes::_ireturn : |
| 238 | case Bytecodes::_lreturn : |
| 239 | case Bytecodes::_freturn : |
| 240 | case Bytecodes::_dreturn : |
| 241 | case Bytecodes::_areturn : |
| 242 | case Bytecodes::_return : |
| 243 | cur_block->set_control_bci(bci); |
| 244 | if (s.next_bci() < limit_bci) { |
| 245 | (void) make_block_at(s.next_bci()); |
| 246 | } |
| 247 | break; |
| 248 | |
| 249 | default: |
| 250 | break; |
| 251 | } |
| 252 | } |
| 253 | // End the last block |
| 254 | cur_block->set_limit_bci(limit_bci); |
| 255 | } |
| 256 | |
| 257 | ciMethodBlocks::ciMethodBlocks(Arena *arena, ciMethod *meth): _method(meth), |
| 258 | _arena(arena), _num_blocks(0), _code_size(meth->code_size()) { |
| 259 | int block_estimate = _code_size / 8; |
| 260 | |
| 261 | _blocks = new(_arena) GrowableArray<ciBlock *>(_arena, block_estimate, 0, NULL__null); |
| 262 | int b2bsize = _code_size * sizeof(ciBlock **); |
| 263 | _bci_to_block = (ciBlock **) arena->Amalloc(b2bsize); |
| 264 | Copy::zero_to_words((HeapWord*) _bci_to_block, b2bsize / sizeof(HeapWord)); |
| 265 | |
| 266 | // create initial block covering the entire method |
| 267 | ciBlock *b = new(arena) ciBlock(_method, _num_blocks++, 0); |
| 268 | _blocks->append(b); |
| 269 | _bci_to_block[0] = b; |
| 270 | |
| 271 | // create blocks for exception handlers |
| 272 | if (meth->has_exception_handlers()) { |
| 273 | for(ciExceptionHandlerStream str(meth); !str.is_done(); str.next()) { |
| 274 | ciExceptionHandler* handler = str.handler(); |
| 275 | ciBlock *eb = make_block_at(handler->handler_bci()); |
| 276 | // |
| 277 | // Several exception handlers can have the same handler_bci: |
| 278 | // |
| 279 | // try { |
| 280 | // if (a.foo(b) < 0) { |
| 281 | // return a.error(); |
| 282 | // } |
| 283 | // return CoderResult.UNDERFLOW; |
| 284 | // } finally { |
| 285 | // a.position(b); |
| 286 | // } |
| 287 | // |
| 288 | // The try block above is divided into 2 exception blocks |
| 289 | // separated by 'areturn' bci. |
| 290 | // |
| 291 | int ex_start = handler->start(); |
| 292 | int ex_end = handler->limit(); |
| 293 | // ensure a block at the start of exception range and start of following code |
| 294 | (void) make_block_at(ex_start); |
| 295 | if (ex_end < _code_size) |
| 296 | (void) make_block_at(ex_end); |
| 297 | |
| 298 | if (eb->is_handler()) { |
| 299 | // Extend old handler exception range to cover additional range. |
| 300 | int old_ex_start = eb->ex_start_bci(); |
| 301 | int old_ex_end = eb->ex_limit_bci(); |
| 302 | if (ex_start > old_ex_start) |
| 303 | ex_start = old_ex_start; |
| 304 | if (ex_end < old_ex_end) |
| 305 | ex_end = old_ex_end; |
| 306 | eb->clear_exception_handler(); // Reset exception information |
| 307 | } |
| 308 | eb->set_exception_range(ex_start, ex_end); |
| 309 | } |
| 310 | } |
| 311 | |
| 312 | // scan the bytecodes and identify blocks |
| 313 | do_analysis(); |
| 314 | |
| 315 | // mark blocks that have exception handlers |
| 316 | if (meth->has_exception_handlers()) { |
| 317 | for(ciExceptionHandlerStream str(meth); !str.is_done(); str.next()) { |
| 318 | ciExceptionHandler* handler = str.handler(); |
| 319 | int ex_start = handler->start(); |
| 320 | int ex_end = handler->limit(); |
| 321 | |
| 322 | int bci = ex_start; |
| 323 | while (bci < ex_end) { |
| 324 | ciBlock *b = block_containing(bci); |
| 325 | b->set_has_handler(); |
| 326 | bci = b->limit_bci(); |
| 327 | } |
| 328 | } |
| 329 | } |
| 330 | } |
| 331 | |
| 332 | void ciMethodBlocks::clear_processed() { |
| 333 | for (int i = 0; i < _blocks->length(); i++) |
| 334 | _blocks->at(i)->clear_processed(); |
| 335 | } |
| 336 | |
| 337 | #ifndef PRODUCT |
| 338 | void ciMethodBlocks::dump() { |
| 339 | tty->print("---- blocks for method: "); |
| 340 | _method->print(); |
| 341 | tty->cr(); |
| 342 | for (int i = 0; i < _blocks->length(); i++) { |
| 343 | tty->print(" B%d: ", i); _blocks->at(i)->dump(); |
| 344 | } |
| 345 | } |
| 346 | #endif |
| 347 | |
| 348 | ciBlock::ciBlock(ciMethod *method, int index, int start_bci) : |
| 349 | _idx(index), _start_bci(start_bci), _limit_bci(-1), _control_bci(fall_through_bci), |
| 350 | _flags(0), _ex_start_bci(-1), _ex_limit_bci(-1) |
| 351 | #ifndef PRODUCT |
| 352 | , _method(method) |
| 353 | #endif |
| 354 | { |
| 355 | } |
| 356 | |
| 357 | void ciBlock::set_exception_range(int start_bci, int limit_bci) { |
| 358 | assert(limit_bci >= start_bci, "valid range")do { if (!(limit_bci >= start_bci)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/ci/ciMethodBlocks.cpp" , 358, "assert(" "limit_bci >= start_bci" ") failed", "valid range" ); ::breakpoint(); } } while (0); |
| 359 | assert(!is_handler() && _ex_start_bci == -1 && _ex_limit_bci == -1, "must not be handler")do { if (!(!is_handler() && _ex_start_bci == -1 && _ex_limit_bci == -1)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/ci/ciMethodBlocks.cpp" , 359, "assert(" "!is_handler() && _ex_start_bci == -1 && _ex_limit_bci == -1" ") failed", "must not be handler"); ::breakpoint(); } } while (0); |
| 360 | _ex_start_bci = start_bci; |
| 361 | _ex_limit_bci = limit_bci; |
| 362 | set_handler(); |
| 363 | } |
| 364 | |
| 365 | #ifndef PRODUCT |
| 366 | static const char *flagnames[] = { |
| 367 | "Processed", |
| 368 | "Handler", |
| 369 | "MayThrow", |
| 370 | "Jsr", |
| 371 | "Ret", |
| 372 | "RetTarget", |
| 373 | "HasHandler", |
| 374 | }; |
| 375 | |
| 376 | void ciBlock::dump() { |
| 377 | tty->print(" [%d .. %d), {", _start_bci, _limit_bci); |
| 378 | for (int i = 0; i < 7; i++) { |
| 379 | if ((_flags & (1 << i)) != 0) { |
| 380 | tty->print(" %s", flagnames[i]); |
| 381 | } |
| 382 | } |
| 383 | tty->print(" ]"); |
| 384 | if (is_handler()) |
| 385 | tty->print(" handles(%d..%d)", _ex_start_bci, _ex_limit_bci); |
| 386 | tty->cr(); |
| 387 | } |
| 388 | |
| 389 | // ------------------------------------------------------------------ |
| 390 | // ciBlock::print_on |
| 391 | void ciBlock::print_on(outputStream* st) const { |
| 392 | st->print_cr("--------------------------------------------------------"); |
| 393 | st->print ("ciBlock [%d - %d) control : ", start_bci(), limit_bci()); |
| 394 | if (control_bci() == fall_through_bci) { |
| 395 | st->print_cr("%d:fall through", limit_bci()); |
| 396 | } else { |
| 397 | st->print_cr("%d:%s", control_bci(), |
| 398 | Bytecodes::name(method()->java_code_at_bci(control_bci()))); |
| 399 | } |
| 400 | |
| 401 | if (Verbose || WizardMode) { |
| 402 | method()->print_codes_on(start_bci(), limit_bci(), st); |
| 403 | } |
| 404 | } |
| 405 | #endif |