| File: | var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp |
| Warning: | line 484, column 9 Value stored to 'first' is never read |
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| 1 | /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
| 2 | * vim: set ts=8 sts=2 et sw=2 tw=80: |
| 3 | * This Source Code Form is subject to the terms of the Mozilla Public |
| 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| 5 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| 6 | |
| 7 | #include "jit/RangeAnalysis.h" |
| 8 | |
| 9 | #include "mozilla/MathAlgorithms.h" |
| 10 | |
| 11 | #include <algorithm> |
| 12 | |
| 13 | #include "jsmath.h" |
| 14 | |
| 15 | #include "jit/CompileInfo.h" |
| 16 | #include "jit/IonAnalysis.h" |
| 17 | #include "jit/JitSpewer.h" |
| 18 | #include "jit/MIR-wasm.h" |
| 19 | #include "jit/MIR.h" |
| 20 | #include "jit/MIRGenerator.h" |
| 21 | #include "jit/MIRGraph.h" |
| 22 | #include "js/Conversions.h" |
| 23 | #include "js/ScalarType.h" // js::Scalar::Type |
| 24 | #include "util/CheckedArithmetic.h" |
| 25 | #include "util/Unicode.h" |
| 26 | #include "vm/ArgumentsObject.h" |
| 27 | #include "vm/Float16.h" |
| 28 | #include "vm/TypedArrayObject.h" |
| 29 | #include "vm/Uint8Clamped.h" |
| 30 | |
| 31 | #include "vm/BytecodeUtil-inl.h" |
| 32 | |
| 33 | using namespace js; |
| 34 | using namespace js::jit; |
| 35 | |
| 36 | using JS::GenericNaN; |
| 37 | using JS::ToInt32; |
| 38 | using mozilla::Abs; |
| 39 | using mozilla::CountLeadingZeroes32; |
| 40 | using mozilla::ExponentComponent; |
| 41 | using mozilla::FloorLog2; |
| 42 | using mozilla::IsNegativeZero; |
| 43 | using mozilla::NegativeInfinity; |
| 44 | using mozilla::NumberEqualsInt32; |
| 45 | using mozilla::PositiveInfinity; |
| 46 | |
| 47 | // [SMDOC] IonMonkey Range Analysis |
| 48 | // |
| 49 | // This algorithm is based on the paper "Eliminating Range Checks Using |
| 50 | // Static Single Assignment Form" by Gough and Klaren. |
| 51 | // |
| 52 | // We associate a range object with each SSA name, and the ranges are consulted |
| 53 | // in order to determine whether overflow is possible for arithmetic |
| 54 | // computations. |
| 55 | // |
| 56 | // An important source of range information that requires care to take |
| 57 | // advantage of is conditional control flow. Consider the code below: |
| 58 | // |
| 59 | // if (x < 0) { |
| 60 | // y = x + 2000000000; |
| 61 | // } else { |
| 62 | // if (x < 1000000000) { |
| 63 | // y = x * 2; |
| 64 | // } else { |
| 65 | // y = x - 3000000000; |
| 66 | // } |
| 67 | // } |
| 68 | // |
| 69 | // The arithmetic operations in this code cannot overflow, but it is not |
| 70 | // sufficient to simply associate each name with a range, since the information |
| 71 | // differs between basic blocks. The traditional dataflow approach would be |
| 72 | // associate ranges with (name, basic block) pairs. This solution is not |
| 73 | // satisfying, since we lose the benefit of SSA form: in SSA form, each |
| 74 | // definition has a unique name, so there is no need to track information about |
| 75 | // the control flow of the program. |
| 76 | // |
| 77 | // The approach used here is to add a new form of pseudo operation called a |
| 78 | // beta node, which associates range information with a value. These beta |
| 79 | // instructions take one argument and additionally have an auxiliary constant |
| 80 | // range associated with them. Operationally, beta nodes are just copies, but |
| 81 | // the invariant expressed by beta node copies is that the output will fall |
| 82 | // inside the range given by the beta node. Gough and Klaeren refer to SSA |
| 83 | // extended with these beta nodes as XSA form. The following shows the example |
| 84 | // code transformed into XSA form: |
| 85 | // |
| 86 | // if (x < 0) { |
| 87 | // x1 = Beta(x, [INT_MIN, -1]); |
| 88 | // y1 = x1 + 2000000000; |
| 89 | // } else { |
| 90 | // x2 = Beta(x, [0, INT_MAX]); |
| 91 | // if (x2 < 1000000000) { |
| 92 | // x3 = Beta(x2, [INT_MIN, 999999999]); |
| 93 | // y2 = x3*2; |
| 94 | // } else { |
| 95 | // x4 = Beta(x2, [1000000000, INT_MAX]); |
| 96 | // y3 = x4 - 3000000000; |
| 97 | // } |
| 98 | // y4 = Phi(y2, y3); |
| 99 | // } |
| 100 | // y = Phi(y1, y4); |
| 101 | // |
| 102 | // We insert beta nodes for the purposes of range analysis (they might also be |
| 103 | // usefully used for other forms of bounds check elimination) and remove them |
| 104 | // after range analysis is performed. The remaining compiler phases do not ever |
| 105 | // encounter beta nodes. |
| 106 | |
| 107 | static bool IsDominatedUse(MBasicBlock* block, MUse* use) { |
| 108 | MNode* n = use->consumer(); |
| 109 | bool isPhi = n->isDefinition() && n->toDefinition()->isPhi(); |
| 110 | |
| 111 | if (isPhi) { |
| 112 | MPhi* phi = n->toDefinition()->toPhi(); |
| 113 | return block->dominates(phi->block()->getPredecessor(phi->indexOf(use))); |
| 114 | } |
| 115 | |
| 116 | return block->dominates(n->block()); |
| 117 | } |
| 118 | |
| 119 | static inline void SpewRange(MDefinition* def) { |
| 120 | #ifdef JS_JITSPEW1 |
| 121 | if (JitSpewEnabled(JitSpew_Range) && def->type() != MIRType::None && |
| 122 | def->range()) { |
| 123 | JitSpewHeader(JitSpew_Range); |
| 124 | Fprinter& out = JitSpewPrinter(); |
| 125 | out.printf(" "); |
| 126 | def->printName(out); |
| 127 | out.printf(" has range "); |
| 128 | def->range()->dump(out); |
| 129 | out.printf("\n"); |
| 130 | } |
| 131 | #endif |
| 132 | } |
| 133 | |
| 134 | #ifdef JS_JITSPEW1 |
| 135 | static const char* TruncateKindString(TruncateKind kind) { |
| 136 | switch (kind) { |
| 137 | case TruncateKind::NoTruncate: |
| 138 | return "NoTruncate"; |
| 139 | case TruncateKind::TruncateAfterBailouts: |
| 140 | return "TruncateAfterBailouts"; |
| 141 | case TruncateKind::IndirectTruncate: |
| 142 | return "IndirectTruncate"; |
| 143 | case TruncateKind::Truncate: |
| 144 | return "Truncate"; |
| 145 | default: |
| 146 | MOZ_CRASH("Unknown truncate kind.")do { do { } while (false); MOZ_ReportCrash("" "Unknown truncate kind." , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 146); AnnotateMozCrashReason("MOZ_CRASH(" "Unknown truncate kind." ")"); do { *((volatile int*)__null) = 146; __attribute__((nomerge )) ::abort(); } while (false); } while (false); |
| 147 | } |
| 148 | } |
| 149 | |
| 150 | static inline void SpewTruncate(MDefinition* def, TruncateKind kind, |
| 151 | bool shouldClone) { |
| 152 | if (JitSpewEnabled(JitSpew_Range)) { |
| 153 | JitSpewHeader(JitSpew_Range); |
| 154 | Fprinter& out = JitSpewPrinter(); |
| 155 | out.printf(" "); |
| 156 | out.printf("truncating "); |
| 157 | def->printName(out); |
| 158 | out.printf(" (kind: %s, clone: %d)\n", TruncateKindString(kind), |
| 159 | shouldClone); |
| 160 | } |
| 161 | } |
| 162 | #else |
| 163 | static inline void SpewTruncate(MDefinition* def, TruncateKind kind, |
| 164 | bool shouldClone) {} |
| 165 | #endif |
| 166 | |
| 167 | TempAllocator& RangeAnalysis::alloc() const { return graph_.alloc(); } |
| 168 | |
| 169 | void RangeAnalysis::replaceDominatedUsesWith(MDefinition* orig, |
| 170 | MDefinition* dom, |
| 171 | MBasicBlock* block) { |
| 172 | for (MUseIterator i(orig->usesBegin()); i != orig->usesEnd();) { |
| 173 | MUse* use = *i++; |
| 174 | if (use->consumer() != dom && IsDominatedUse(block, use)) { |
| 175 | use->replaceProducer(dom); |
| 176 | } |
| 177 | } |
| 178 | } |
| 179 | |
| 180 | bool RangeAnalysis::addBetaNodes() { |
| 181 | JitSpew(JitSpew_Range, "Adding beta nodes"); |
| 182 | |
| 183 | for (PostorderIterator i(graph_.poBegin()); i != graph_.poEnd(); i++) { |
| 184 | MBasicBlock* block = *i; |
| 185 | JitSpew(JitSpew_Range, "Looking at block %u", block->id()); |
| 186 | |
| 187 | BranchDirection branch_dir; |
| 188 | MTest* test = block->immediateDominatorBranch(&branch_dir); |
| 189 | |
| 190 | if (!test || !test->getOperand(0)->isCompare()) { |
| 191 | continue; |
| 192 | } |
| 193 | |
| 194 | MCompare* compare = test->getOperand(0)->toCompare(); |
| 195 | |
| 196 | if (!compare->isNumericComparison()) { |
| 197 | continue; |
| 198 | } |
| 199 | |
| 200 | // TODO: support unsigned comparisons |
| 201 | if (compare->compareType() == MCompare::Compare_UInt32) { |
| 202 | continue; |
| 203 | } |
| 204 | |
| 205 | // isNumericComparison should return false for UIntPtr. |
| 206 | MOZ_ASSERT(compare->compareType() != MCompare::Compare_UIntPtr)do { static_assert( mozilla::detail::AssertionConditionType< decltype(compare->compareType() != MCompare::Compare_UIntPtr )>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(compare->compareType() != MCompare::Compare_UIntPtr ))), 0))) { do { } while (false); MOZ_ReportAssertionFailure( "compare->compareType() != MCompare::Compare_UIntPtr", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 206); AnnotateMozCrashReason("MOZ_ASSERT" "(" "compare->compareType() != MCompare::Compare_UIntPtr" ")"); do { *((volatile int*)__null) = 206; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 207 | |
| 208 | MDefinition* left = compare->getOperand(0); |
| 209 | MDefinition* right = compare->getOperand(1); |
| 210 | double bound; |
| 211 | double conservativeLower = NegativeInfinity<double>(); |
| 212 | double conservativeUpper = PositiveInfinity<double>(); |
| 213 | MDefinition* val = nullptr; |
| 214 | |
| 215 | JSOp jsop = compare->jsop(); |
| 216 | |
| 217 | if (branch_dir == FALSE_BRANCH) { |
| 218 | jsop = NegateCompareOp(jsop); |
| 219 | conservativeLower = GenericNaN(); |
| 220 | conservativeUpper = GenericNaN(); |
| 221 | } |
| 222 | |
| 223 | MConstant* leftConst = left->maybeConstantValue(); |
| 224 | MConstant* rightConst = right->maybeConstantValue(); |
| 225 | if (leftConst && leftConst->isTypeRepresentableAsDouble()) { |
| 226 | bound = leftConst->numberToDouble(); |
| 227 | val = right; |
| 228 | jsop = ReverseCompareOp(jsop); |
| 229 | } else if (rightConst && rightConst->isTypeRepresentableAsDouble()) { |
| 230 | bound = rightConst->numberToDouble(); |
| 231 | val = left; |
| 232 | } else if (left->type() == MIRType::Int32 && |
| 233 | right->type() == MIRType::Int32) { |
| 234 | MDefinition* smaller = nullptr; |
| 235 | MDefinition* greater = nullptr; |
| 236 | if (jsop == JSOp::Lt) { |
| 237 | smaller = left; |
| 238 | greater = right; |
| 239 | } else if (jsop == JSOp::Gt) { |
| 240 | smaller = right; |
| 241 | greater = left; |
| 242 | } |
| 243 | if (smaller && greater) { |
| 244 | if (!alloc().ensureBallast()) { |
| 245 | return false; |
| 246 | } |
| 247 | |
| 248 | MBeta* beta; |
| 249 | beta = MBeta::New( |
| 250 | alloc(), smaller, |
| 251 | Range::NewInt32Range(alloc(), JSVAL_INT_MIN((int32_t)0x80000000), JSVAL_INT_MAX((int32_t)0x7fffffff) - 1)); |
| 252 | block->insertBefore(*block->begin(), beta); |
| 253 | replaceDominatedUsesWith(smaller, beta, block); |
| 254 | JitSpew(JitSpew_Range, " Adding beta node for smaller %u", |
| 255 | smaller->id()); |
| 256 | beta = MBeta::New( |
| 257 | alloc(), greater, |
| 258 | Range::NewInt32Range(alloc(), JSVAL_INT_MIN((int32_t)0x80000000) + 1, JSVAL_INT_MAX((int32_t)0x7fffffff))); |
| 259 | block->insertBefore(*block->begin(), beta); |
| 260 | replaceDominatedUsesWith(greater, beta, block); |
| 261 | JitSpew(JitSpew_Range, " Adding beta node for greater %u", |
| 262 | greater->id()); |
| 263 | } |
| 264 | continue; |
| 265 | } else { |
| 266 | continue; |
| 267 | } |
| 268 | |
| 269 | // At this point, one of the operands if the compare is a constant, and |
| 270 | // val is the other operand. |
| 271 | MOZ_ASSERT(val)do { static_assert( mozilla::detail::AssertionConditionType< decltype(val)>::isValid, "invalid assertion condition"); if ((__builtin_expect(!!(!(!!(val))), 0))) { do { } while (false ); MOZ_ReportAssertionFailure("val", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 271); AnnotateMozCrashReason("MOZ_ASSERT" "(" "val" ")"); do { *((volatile int*)__null) = 271; __attribute__((nomerge)) :: abort(); } while (false); } } while (false); |
| 272 | |
| 273 | Range comp; |
| 274 | switch (jsop) { |
| 275 | case JSOp::Le: |
| 276 | comp.setDouble(conservativeLower, bound); |
| 277 | break; |
| 278 | case JSOp::Lt: |
| 279 | // For integers, if x < c, the upper bound of x is c-1. |
| 280 | if (val->type() == MIRType::Int32) { |
| 281 | int32_t intbound; |
| 282 | if (NumberEqualsInt32(bound, &intbound) && |
| 283 | SafeSub(intbound, 1, &intbound)) { |
| 284 | bound = intbound; |
| 285 | } |
| 286 | } |
| 287 | comp.setDouble(conservativeLower, bound); |
| 288 | |
| 289 | // Negative zero is not less than zero. |
| 290 | if (bound == 0) { |
| 291 | comp.refineToExcludeNegativeZero(); |
| 292 | } |
| 293 | break; |
| 294 | case JSOp::Ge: |
| 295 | comp.setDouble(bound, conservativeUpper); |
| 296 | break; |
| 297 | case JSOp::Gt: |
| 298 | // For integers, if x > c, the lower bound of x is c+1. |
| 299 | if (val->type() == MIRType::Int32) { |
| 300 | int32_t intbound; |
| 301 | if (NumberEqualsInt32(bound, &intbound) && |
| 302 | SafeAdd(intbound, 1, &intbound)) { |
| 303 | bound = intbound; |
| 304 | } |
| 305 | } |
| 306 | comp.setDouble(bound, conservativeUpper); |
| 307 | |
| 308 | // Negative zero is not greater than zero. |
| 309 | if (bound == 0) { |
| 310 | comp.refineToExcludeNegativeZero(); |
| 311 | } |
| 312 | break; |
| 313 | case JSOp::StrictEq: |
| 314 | case JSOp::Eq: |
| 315 | comp.setDouble(bound, bound); |
| 316 | break; |
| 317 | case JSOp::StrictNe: |
| 318 | case JSOp::Ne: |
| 319 | // Negative zero is not not-equal to zero. |
| 320 | if (bound == 0) { |
| 321 | comp.refineToExcludeNegativeZero(); |
| 322 | break; |
| 323 | } |
| 324 | continue; // well, we could have |
| 325 | // [-\inf, bound-1] U [bound+1, \inf] but we only use |
| 326 | // contiguous ranges. |
| 327 | default: |
| 328 | continue; |
| 329 | } |
| 330 | |
| 331 | if (JitSpewEnabled(JitSpew_Range)) { |
| 332 | JitSpewHeader(JitSpew_Range); |
| 333 | Fprinter& out = JitSpewPrinter(); |
| 334 | out.printf(" Adding beta node for %u with range ", val->id()); |
| 335 | comp.dump(out); |
| 336 | out.printf("\n"); |
| 337 | } |
| 338 | |
| 339 | if (!alloc().ensureBallast()) { |
| 340 | return false; |
| 341 | } |
| 342 | |
| 343 | MBeta* beta = MBeta::New(alloc(), val, new (alloc()) Range(comp)); |
| 344 | block->insertBefore(*block->begin(), beta); |
| 345 | replaceDominatedUsesWith(val, beta, block); |
| 346 | } |
| 347 | |
| 348 | return true; |
| 349 | } |
| 350 | |
| 351 | bool RangeAnalysis::removeBetaNodes() { |
| 352 | JitSpew(JitSpew_Range, "Removing beta nodes"); |
| 353 | |
| 354 | for (PostorderIterator i(graph_.poBegin()); i != graph_.poEnd(); i++) { |
| 355 | MBasicBlock* block = *i; |
| 356 | for (MDefinitionIterator iter(*i); iter;) { |
| 357 | MDefinition* def = *iter++; |
| 358 | if (def->isBeta()) { |
| 359 | auto* beta = def->toBeta(); |
| 360 | MDefinition* op = beta->input(); |
| 361 | JitSpew(JitSpew_Range, " Removing beta node %u for %u", beta->id(), |
| 362 | op->id()); |
| 363 | beta->justReplaceAllUsesWith(op); |
| 364 | block->discard(beta); |
| 365 | } else { |
| 366 | // We only place Beta nodes at the beginning of basic |
| 367 | // blocks, so if we see something else, we can move on |
| 368 | // to the next block. |
| 369 | break; |
| 370 | } |
| 371 | } |
| 372 | } |
| 373 | return true; |
| 374 | } |
| 375 | |
| 376 | void SymbolicBound::dump(GenericPrinter& out) const { |
| 377 | if (loop) { |
| 378 | out.printf("[loop] "); |
| 379 | } |
| 380 | sum.dump(out); |
| 381 | } |
| 382 | |
| 383 | void SymbolicBound::dump() const { |
| 384 | Fprinter out(stderrstderr); |
| 385 | dump(out); |
| 386 | out.printf("\n"); |
| 387 | out.finish(); |
| 388 | } |
| 389 | |
| 390 | // Test whether the given range's exponent tells us anything that its lower |
| 391 | // and upper bound values don't. |
| 392 | static bool IsExponentInteresting(const Range* r) { |
| 393 | // If it lacks either a lower or upper bound, the exponent is interesting. |
| 394 | if (!r->hasInt32Bounds()) { |
| 395 | return true; |
| 396 | } |
| 397 | |
| 398 | // Otherwise if there's no fractional part, the lower and upper bounds, |
| 399 | // which are integers, are perfectly precise. |
| 400 | if (!r->canHaveFractionalPart()) { |
| 401 | return false; |
| 402 | } |
| 403 | |
| 404 | // Otherwise, if the bounds are conservatively rounded across a power-of-two |
| 405 | // boundary, the exponent may imply a tighter range. |
| 406 | return FloorLog2(std::max(Abs(r->lower()), Abs(r->upper()))) > r->exponent(); |
| 407 | } |
| 408 | |
| 409 | void Range::dump(GenericPrinter& out) const { |
| 410 | assertInvariants(); |
| 411 | |
| 412 | // Floating-point or Integer subset. |
| 413 | if (canHaveFractionalPart_) { |
| 414 | out.printf("F"); |
| 415 | } else { |
| 416 | out.printf("I"); |
| 417 | } |
| 418 | |
| 419 | out.printf("["); |
| 420 | |
| 421 | if (!hasInt32LowerBound_) { |
| 422 | out.printf("?"); |
| 423 | } else { |
| 424 | out.printf("%d", lower_); |
| 425 | } |
| 426 | if (symbolicLower_) { |
| 427 | out.printf(" {"); |
| 428 | symbolicLower_->dump(out); |
| 429 | out.printf("}"); |
| 430 | } |
| 431 | |
| 432 | out.printf(", "); |
| 433 | |
| 434 | if (!hasInt32UpperBound_) { |
| 435 | out.printf("?"); |
| 436 | } else { |
| 437 | out.printf("%d", upper_); |
| 438 | } |
| 439 | if (symbolicUpper_) { |
| 440 | out.printf(" {"); |
| 441 | symbolicUpper_->dump(out); |
| 442 | out.printf("}"); |
| 443 | } |
| 444 | |
| 445 | out.printf("]"); |
| 446 | |
| 447 | bool includesNaN = max_exponent_ == IncludesInfinityAndNaN; |
| 448 | bool includesNegativeInfinity = |
| 449 | max_exponent_ >= IncludesInfinity && !hasInt32LowerBound_; |
| 450 | bool includesPositiveInfinity = |
| 451 | max_exponent_ >= IncludesInfinity && !hasInt32UpperBound_; |
| 452 | bool includesNegativeZero = canBeNegativeZero_; |
| 453 | |
| 454 | if (includesNaN || includesNegativeInfinity || includesPositiveInfinity || |
| 455 | includesNegativeZero) { |
| 456 | out.printf(" ("); |
| 457 | bool first = true; |
| 458 | if (includesNaN) { |
| 459 | if (first) { |
| 460 | first = false; |
| 461 | } else { |
| 462 | out.printf(" "); |
| 463 | } |
| 464 | out.printf("U NaN"); |
| 465 | } |
| 466 | if (includesNegativeInfinity) { |
| 467 | if (first) { |
| 468 | first = false; |
| 469 | } else { |
| 470 | out.printf(" "); |
| 471 | } |
| 472 | out.printf("U -Infinity"); |
| 473 | } |
| 474 | if (includesPositiveInfinity) { |
| 475 | if (first) { |
| 476 | first = false; |
| 477 | } else { |
| 478 | out.printf(" "); |
| 479 | } |
| 480 | out.printf("U Infinity"); |
| 481 | } |
| 482 | if (includesNegativeZero) { |
| 483 | if (first) { |
| 484 | first = false; |
Value stored to 'first' is never read | |
| 485 | } else { |
| 486 | out.printf(" "); |
| 487 | } |
| 488 | out.printf("U -0"); |
| 489 | } |
| 490 | out.printf(")"); |
| 491 | } |
| 492 | if (max_exponent_ < IncludesInfinity && IsExponentInteresting(this)) { |
| 493 | out.printf(" (< pow(2, %d+1))", max_exponent_); |
| 494 | } |
| 495 | } |
| 496 | |
| 497 | void Range::dump() const { |
| 498 | Fprinter out(stderrstderr); |
| 499 | dump(out); |
| 500 | out.printf("\n"); |
| 501 | out.finish(); |
| 502 | } |
| 503 | |
| 504 | Range* Range::intersect(TempAllocator& alloc, const Range* lhs, |
| 505 | const Range* rhs, bool* emptyRange) { |
| 506 | *emptyRange = false; |
| 507 | |
| 508 | if (!lhs && !rhs) { |
| 509 | return nullptr; |
| 510 | } |
| 511 | |
| 512 | if (!lhs) { |
| 513 | return new (alloc) Range(*rhs); |
| 514 | } |
| 515 | if (!rhs) { |
| 516 | return new (alloc) Range(*lhs); |
| 517 | } |
| 518 | |
| 519 | int32_t newLower = std::max(lhs->lower_, rhs->lower_); |
| 520 | int32_t newUpper = std::min(lhs->upper_, rhs->upper_); |
| 521 | |
| 522 | // If upper < lower, then we have conflicting constraints. Consider: |
| 523 | // |
| 524 | // if (x < 0) { |
| 525 | // if (x > 0) { |
| 526 | // [Some code.] |
| 527 | // } |
| 528 | // } |
| 529 | // |
| 530 | // In this case, the block is unreachable. |
| 531 | if (newUpper < newLower) { |
| 532 | // If both ranges can be NaN, the result can still be NaN. |
| 533 | if (!lhs->canBeNaN() || !rhs->canBeNaN()) { |
| 534 | *emptyRange = true; |
| 535 | } |
| 536 | return nullptr; |
| 537 | } |
| 538 | |
| 539 | bool newHasInt32LowerBound = |
| 540 | lhs->hasInt32LowerBound_ || rhs->hasInt32LowerBound_; |
| 541 | bool newHasInt32UpperBound = |
| 542 | lhs->hasInt32UpperBound_ || rhs->hasInt32UpperBound_; |
| 543 | |
| 544 | FractionalPartFlag newCanHaveFractionalPart = FractionalPartFlag( |
| 545 | lhs->canHaveFractionalPart_ && rhs->canHaveFractionalPart_); |
| 546 | NegativeZeroFlag newMayIncludeNegativeZero = |
| 547 | NegativeZeroFlag(lhs->canBeNegativeZero_ && rhs->canBeNegativeZero_); |
| 548 | |
| 549 | uint16_t newExponent = std::min(lhs->max_exponent_, rhs->max_exponent_); |
| 550 | |
| 551 | // NaN is a special value which is neither greater than infinity or less than |
| 552 | // negative infinity. When we intersect two ranges like [?, 0] and [0, ?], we |
| 553 | // can end up thinking we have both a lower and upper bound, even though NaN |
| 554 | // is still possible. In this case, just be conservative, since any case where |
| 555 | // we can have NaN is not especially interesting. |
| 556 | if (newHasInt32LowerBound && newHasInt32UpperBound && |
| 557 | newExponent == IncludesInfinityAndNaN) { |
| 558 | return nullptr; |
| 559 | } |
| 560 | |
| 561 | // If one of the ranges has a fractional part and the other doesn't, it's |
| 562 | // possible that we will have computed a newExponent that's more precise |
| 563 | // than our newLower and newUpper. This is unusual, so we handle it here |
| 564 | // instead of in optimize(). |
| 565 | // |
| 566 | // For example, consider the range F[0,1.5]. Range analysis represents the |
| 567 | // lower and upper bound as integers, so we'd actually have |
| 568 | // F[0,2] (< pow(2, 0+1)). In this case, the exponent gives us a slightly |
| 569 | // more precise upper bound than the integer upper bound. |
| 570 | // |
| 571 | // When intersecting such a range with an integer range, the fractional part |
| 572 | // of the range is dropped. The max exponent of 0 remains valid, so the |
| 573 | // upper bound needs to be adjusted to 1. |
| 574 | // |
| 575 | // When intersecting F[0,2] (< pow(2, 0+1)) with a range like F[2,4], |
| 576 | // the naive intersection is I[2,2], but since the max exponent tells us |
| 577 | // that the value is always less than 2, the intersection is actually empty. |
| 578 | if (lhs->canHaveFractionalPart() != rhs->canHaveFractionalPart() || |
| 579 | (lhs->canHaveFractionalPart() && newHasInt32LowerBound && |
| 580 | newHasInt32UpperBound && newLower == newUpper)) { |
| 581 | refineInt32BoundsByExponent(newExponent, &newLower, &newHasInt32LowerBound, |
| 582 | &newUpper, &newHasInt32UpperBound); |
| 583 | |
| 584 | // If we're intersecting two ranges that don't overlap, this could also |
| 585 | // push the bounds past each other, since the actual intersection is |
| 586 | // the empty set. |
| 587 | if (newLower > newUpper) { |
| 588 | *emptyRange = true; |
| 589 | return nullptr; |
| 590 | } |
| 591 | } |
| 592 | |
| 593 | return new (alloc) |
| 594 | Range(newLower, newHasInt32LowerBound, newUpper, newHasInt32UpperBound, |
| 595 | newCanHaveFractionalPart, newMayIncludeNegativeZero, newExponent); |
| 596 | } |
| 597 | |
| 598 | void Range::unionWith(const Range* other) { |
| 599 | int32_t newLower = std::min(lower_, other->lower_); |
| 600 | int32_t newUpper = std::max(upper_, other->upper_); |
| 601 | |
| 602 | bool newHasInt32LowerBound = |
| 603 | hasInt32LowerBound_ && other->hasInt32LowerBound_; |
| 604 | bool newHasInt32UpperBound = |
| 605 | hasInt32UpperBound_ && other->hasInt32UpperBound_; |
| 606 | |
| 607 | FractionalPartFlag newCanHaveFractionalPart = FractionalPartFlag( |
| 608 | canHaveFractionalPart_ || other->canHaveFractionalPart_); |
| 609 | NegativeZeroFlag newMayIncludeNegativeZero = |
| 610 | NegativeZeroFlag(canBeNegativeZero_ || other->canBeNegativeZero_); |
| 611 | |
| 612 | uint16_t newExponent = std::max(max_exponent_, other->max_exponent_); |
| 613 | |
| 614 | rawInitialize(newLower, newHasInt32LowerBound, newUpper, |
| 615 | newHasInt32UpperBound, newCanHaveFractionalPart, |
| 616 | newMayIncludeNegativeZero, newExponent); |
| 617 | } |
| 618 | |
| 619 | Range::Range(const MDefinition* def) |
| 620 | : symbolicLower_(nullptr), symbolicUpper_(nullptr) { |
| 621 | if (const Range* other = def->range()) { |
| 622 | // The instruction has range information; use it. |
| 623 | *this = *other; |
| 624 | |
| 625 | // Simulate the effect of converting the value to its type. |
| 626 | // Note: we cannot clamp here, since ranges aren't allowed to shrink |
| 627 | // and truncation can increase range again. So doing wrapAround to |
| 628 | // mimick a possible truncation. |
| 629 | switch (def->type()) { |
| 630 | case MIRType::Int32: |
| 631 | // MToNumberInt32 cannot truncate. So we can safely clamp. |
| 632 | if (def->isToNumberInt32()) { |
| 633 | clampToInt32(); |
| 634 | } else { |
| 635 | wrapAroundToInt32(); |
| 636 | } |
| 637 | break; |
| 638 | case MIRType::Boolean: |
| 639 | wrapAroundToBoolean(); |
| 640 | break; |
| 641 | case MIRType::None: |
| 642 | MOZ_CRASH("Asking for the range of an instruction with no value")do { do { } while (false); MOZ_ReportCrash("" "Asking for the range of an instruction with no value" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 642); AnnotateMozCrashReason("MOZ_CRASH(" "Asking for the range of an instruction with no value" ")"); do { *((volatile int*)__null) = 642; __attribute__((nomerge )) ::abort(); } while (false); } while (false); |
| 643 | default: |
| 644 | break; |
| 645 | } |
| 646 | } else { |
| 647 | // Otherwise just use type information. We can trust the type here |
| 648 | // because we don't care what value the instruction actually produces, |
| 649 | // but what value we might get after we get past the bailouts. |
| 650 | switch (def->type()) { |
| 651 | case MIRType::Int32: |
| 652 | setInt32(JSVAL_INT_MIN((int32_t)0x80000000), JSVAL_INT_MAX((int32_t)0x7fffffff)); |
| 653 | break; |
| 654 | case MIRType::Boolean: |
| 655 | setInt32(0, 1); |
| 656 | break; |
| 657 | case MIRType::None: |
| 658 | MOZ_CRASH("Asking for the range of an instruction with no value")do { do { } while (false); MOZ_ReportCrash("" "Asking for the range of an instruction with no value" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 658); AnnotateMozCrashReason("MOZ_CRASH(" "Asking for the range of an instruction with no value" ")"); do { *((volatile int*)__null) = 658; __attribute__((nomerge )) ::abort(); } while (false); } while (false); |
| 659 | default: |
| 660 | setUnknown(); |
| 661 | break; |
| 662 | } |
| 663 | } |
| 664 | |
| 665 | // As a special case, MUrsh is permitted to claim a result type of |
| 666 | // MIRType::Int32 while actually returning values in [0,UINT32_MAX] without |
| 667 | // bailouts. If range analysis hasn't ruled out values in |
| 668 | // (INT32_MAX,UINT32_MAX], set the range to be conservatively correct for |
| 669 | // use as either a uint32 or an int32. |
| 670 | if (!hasInt32UpperBound() && def->isUrsh() && |
| 671 | def->toUrsh()->bailoutsDisabled() && def->type() != MIRType::Int64) { |
| 672 | lower_ = INT32_MIN(-2147483647-1); |
| 673 | } |
| 674 | |
| 675 | assertInvariants(); |
| 676 | } |
| 677 | |
| 678 | static uint16_t ExponentImpliedByDouble(double d) { |
| 679 | // Handle the special values. |
| 680 | if (std::isnan(d)) { |
| 681 | return Range::IncludesInfinityAndNaN; |
| 682 | } |
| 683 | if (std::isinf(d)) { |
| 684 | return Range::IncludesInfinity; |
| 685 | } |
| 686 | |
| 687 | // Otherwise take the exponent part and clamp it at zero, since the Range |
| 688 | // class doesn't track fractional ranges. |
| 689 | return uint16_t(std::max(int_fast16_t(0), ExponentComponent(d))); |
| 690 | } |
| 691 | |
| 692 | void Range::setDouble(double l, double h) { |
| 693 | MOZ_ASSERT(!(l > h))do { static_assert( mozilla::detail::AssertionConditionType< decltype(!(l > h))>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(!(l > h)))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("!(l > h)", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 693); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!(l > h)" ")"); do { *((volatile int*)__null) = 693; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 694 | |
| 695 | // Infer lower_, upper_, hasInt32LowerBound_, and hasInt32UpperBound_. |
| 696 | if (l >= INT32_MIN(-2147483647-1) && l <= INT32_MAX(2147483647)) { |
| 697 | lower_ = int32_t(::floor(l)); |
| 698 | hasInt32LowerBound_ = true; |
| 699 | } else if (l >= INT32_MAX(2147483647)) { |
| 700 | lower_ = INT32_MAX(2147483647); |
| 701 | hasInt32LowerBound_ = true; |
| 702 | } else { |
| 703 | lower_ = INT32_MIN(-2147483647-1); |
| 704 | hasInt32LowerBound_ = false; |
| 705 | } |
| 706 | if (h >= INT32_MIN(-2147483647-1) && h <= INT32_MAX(2147483647)) { |
| 707 | upper_ = int32_t(::ceil(h)); |
| 708 | hasInt32UpperBound_ = true; |
| 709 | } else if (h <= INT32_MIN(-2147483647-1)) { |
| 710 | upper_ = INT32_MIN(-2147483647-1); |
| 711 | hasInt32UpperBound_ = true; |
| 712 | } else { |
| 713 | upper_ = INT32_MAX(2147483647); |
| 714 | hasInt32UpperBound_ = false; |
| 715 | } |
| 716 | |
| 717 | // Infer max_exponent_. |
| 718 | uint16_t lExp = ExponentImpliedByDouble(l); |
| 719 | uint16_t hExp = ExponentImpliedByDouble(h); |
| 720 | max_exponent_ = std::max(lExp, hExp); |
| 721 | |
| 722 | canHaveFractionalPart_ = ExcludesFractionalParts; |
| 723 | canBeNegativeZero_ = ExcludesNegativeZero; |
| 724 | |
| 725 | // Infer the canHaveFractionalPart_ setting. We can have a |
| 726 | // fractional part if the range crosses through the neighborhood of zero. We |
| 727 | // won't have a fractional value if the value is always beyond the point at |
| 728 | // which double precision can't represent fractional values. |
| 729 | uint16_t minExp = std::min(lExp, hExp); |
| 730 | bool includesNegative = std::isnan(l) || l < 0; |
| 731 | bool includesPositive = std::isnan(h) || h > 0; |
| 732 | bool crossesZero = includesNegative && includesPositive; |
| 733 | if (crossesZero || minExp < MaxTruncatableExponent) { |
| 734 | canHaveFractionalPart_ = IncludesFractionalParts; |
| 735 | } |
| 736 | |
| 737 | // Infer the canBeNegativeZero_ setting. We can have a negative zero if |
| 738 | // either bound is zero. |
| 739 | if (!(l > 0) && !(h < 0)) { |
| 740 | canBeNegativeZero_ = IncludesNegativeZero; |
| 741 | } |
| 742 | |
| 743 | optimize(); |
| 744 | } |
| 745 | |
| 746 | void Range::setDoubleSingleton(double d) { |
| 747 | setDouble(d, d); |
| 748 | |
| 749 | // The above setDouble call is for comparisons, and treats negative zero |
| 750 | // as equal to zero. We're aiming for a minimum range, so we can clear the |
| 751 | // negative zero flag if the value isn't actually negative zero. |
| 752 | if (!IsNegativeZero(d)) { |
| 753 | canBeNegativeZero_ = ExcludesNegativeZero; |
| 754 | } |
| 755 | |
| 756 | assertInvariants(); |
| 757 | } |
| 758 | |
| 759 | static inline bool MissingAnyInt32Bounds(const Range* lhs, const Range* rhs) { |
| 760 | return !lhs->hasInt32Bounds() || !rhs->hasInt32Bounds(); |
| 761 | } |
| 762 | |
| 763 | Range* Range::add(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 764 | int64_t l = (int64_t)lhs->lower_ + (int64_t)rhs->lower_; |
| 765 | if (!lhs->hasInt32LowerBound() || !rhs->hasInt32LowerBound()) { |
| 766 | l = NoInt32LowerBound; |
| 767 | } |
| 768 | |
| 769 | int64_t h = (int64_t)lhs->upper_ + (int64_t)rhs->upper_; |
| 770 | if (!lhs->hasInt32UpperBound() || !rhs->hasInt32UpperBound()) { |
| 771 | h = NoInt32UpperBound; |
| 772 | } |
| 773 | |
| 774 | // The exponent is at most one greater than the greater of the operands' |
| 775 | // exponents, except for NaN and infinity cases. |
| 776 | uint16_t e = std::max(lhs->max_exponent_, rhs->max_exponent_); |
| 777 | if (e <= Range::MaxFiniteExponent) { |
| 778 | ++e; |
| 779 | } |
| 780 | |
| 781 | // Infinity + -Infinity is NaN. |
| 782 | if (lhs->canBeInfiniteOrNaN() && rhs->canBeInfiniteOrNaN()) { |
| 783 | e = Range::IncludesInfinityAndNaN; |
| 784 | } |
| 785 | |
| 786 | return new (alloc) Range( |
| 787 | l, h, |
| 788 | FractionalPartFlag(lhs->canHaveFractionalPart() || |
| 789 | rhs->canHaveFractionalPart()), |
| 790 | NegativeZeroFlag(lhs->canBeNegativeZero() && rhs->canBeNegativeZero()), |
| 791 | e); |
| 792 | } |
| 793 | |
| 794 | Range* Range::sub(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 795 | int64_t l = (int64_t)lhs->lower_ - (int64_t)rhs->upper_; |
| 796 | if (!lhs->hasInt32LowerBound() || !rhs->hasInt32UpperBound()) { |
| 797 | l = NoInt32LowerBound; |
| 798 | } |
| 799 | |
| 800 | int64_t h = (int64_t)lhs->upper_ - (int64_t)rhs->lower_; |
| 801 | if (!lhs->hasInt32UpperBound() || !rhs->hasInt32LowerBound()) { |
| 802 | h = NoInt32UpperBound; |
| 803 | } |
| 804 | |
| 805 | // The exponent is at most one greater than the greater of the operands' |
| 806 | // exponents, except for NaN and infinity cases. |
| 807 | uint16_t e = std::max(lhs->max_exponent_, rhs->max_exponent_); |
| 808 | if (e <= Range::MaxFiniteExponent) { |
| 809 | ++e; |
| 810 | } |
| 811 | |
| 812 | // Infinity - Infinity is NaN. |
| 813 | if (lhs->canBeInfiniteOrNaN() && rhs->canBeInfiniteOrNaN()) { |
| 814 | e = Range::IncludesInfinityAndNaN; |
| 815 | } |
| 816 | |
| 817 | return new (alloc) |
| 818 | Range(l, h, |
| 819 | FractionalPartFlag(lhs->canHaveFractionalPart() || |
| 820 | rhs->canHaveFractionalPart()), |
| 821 | NegativeZeroFlag(lhs->canBeNegativeZero() && rhs->canBeZero()), e); |
| 822 | } |
| 823 | |
| 824 | Range* Range::and_(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 825 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 825); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 825; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 826 | MOZ_ASSERT(rhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(rhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(rhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("rhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 826); AnnotateMozCrashReason("MOZ_ASSERT" "(" "rhs->isInt32()" ")"); do { *((volatile int*)__null) = 826; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 827 | |
| 828 | // If both numbers can be negative, result can be negative in the whole range |
| 829 | if (lhs->lower() < 0 && rhs->lower() < 0) { |
| 830 | return Range::NewInt32Range(alloc, INT32_MIN(-2147483647-1), |
| 831 | std::max(lhs->upper(), rhs->upper())); |
| 832 | } |
| 833 | |
| 834 | // Only one of both numbers can be negative. |
| 835 | // - result can't be negative |
| 836 | // - Upper bound is minimum of both upper range, |
| 837 | int32_t lower = 0; |
| 838 | int32_t upper = std::min(lhs->upper(), rhs->upper()); |
| 839 | |
| 840 | // EXCEPT when upper bound of non negative number is max value, |
| 841 | // because negative value can return the whole max value. |
| 842 | // -1 & 5 = 5 |
| 843 | if (lhs->lower() < 0) { |
| 844 | upper = rhs->upper(); |
| 845 | } |
| 846 | if (rhs->lower() < 0) { |
| 847 | upper = lhs->upper(); |
| 848 | } |
| 849 | |
| 850 | return Range::NewInt32Range(alloc, lower, upper); |
| 851 | } |
| 852 | |
| 853 | Range* Range::or_(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 854 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 854); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 854; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 855 | MOZ_ASSERT(rhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(rhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(rhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("rhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 855); AnnotateMozCrashReason("MOZ_ASSERT" "(" "rhs->isInt32()" ")"); do { *((volatile int*)__null) = 855; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 856 | // When one operand is always 0 or always -1, it's a special case where we |
| 857 | // can compute a fully precise result. Handling these up front also |
| 858 | // protects the code below from calling CountLeadingZeroes32 with a zero |
| 859 | // operand or from shifting an int32_t by 32. |
| 860 | if (lhs->lower() == lhs->upper()) { |
| 861 | if (lhs->lower() == 0) { |
| 862 | return new (alloc) Range(*rhs); |
| 863 | } |
| 864 | if (lhs->lower() == -1) { |
| 865 | return new (alloc) Range(*lhs); |
| 866 | } |
| 867 | } |
| 868 | if (rhs->lower() == rhs->upper()) { |
| 869 | if (rhs->lower() == 0) { |
| 870 | return new (alloc) Range(*lhs); |
| 871 | } |
| 872 | if (rhs->lower() == -1) { |
| 873 | return new (alloc) Range(*rhs); |
| 874 | } |
| 875 | } |
| 876 | |
| 877 | // The code below uses CountLeadingZeroes32, which has undefined behavior |
| 878 | // if its operand is 0. We rely on the code above to protect it. |
| 879 | MOZ_ASSERT_IF(lhs->lower() >= 0, lhs->upper() != 0)do { if (lhs->lower() >= 0) { do { static_assert( mozilla ::detail::AssertionConditionType<decltype(lhs->upper() != 0)>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(lhs->upper() != 0))), 0))) { do { } while (false) ; MOZ_ReportAssertionFailure("lhs->upper() != 0", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 879); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->upper() != 0" ")"); do { *((volatile int*)__null) = 879; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); } } while ( false); |
| 880 | MOZ_ASSERT_IF(rhs->lower() >= 0, rhs->upper() != 0)do { if (rhs->lower() >= 0) { do { static_assert( mozilla ::detail::AssertionConditionType<decltype(rhs->upper() != 0)>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(rhs->upper() != 0))), 0))) { do { } while (false) ; MOZ_ReportAssertionFailure("rhs->upper() != 0", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 880); AnnotateMozCrashReason("MOZ_ASSERT" "(" "rhs->upper() != 0" ")"); do { *((volatile int*)__null) = 880; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); } } while ( false); |
| 881 | MOZ_ASSERT_IF(lhs->upper() < 0, lhs->lower() != -1)do { if (lhs->upper() < 0) { do { static_assert( mozilla ::detail::AssertionConditionType<decltype(lhs->lower() != -1)>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(lhs->lower() != -1))), 0))) { do { } while (false ); MOZ_ReportAssertionFailure("lhs->lower() != -1", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 881); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->lower() != -1" ")"); do { *((volatile int*)__null) = 881; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); } } while ( false); |
| 882 | MOZ_ASSERT_IF(rhs->upper() < 0, rhs->lower() != -1)do { if (rhs->upper() < 0) { do { static_assert( mozilla ::detail::AssertionConditionType<decltype(rhs->lower() != -1)>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(rhs->lower() != -1))), 0))) { do { } while (false ); MOZ_ReportAssertionFailure("rhs->lower() != -1", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 882); AnnotateMozCrashReason("MOZ_ASSERT" "(" "rhs->lower() != -1" ")"); do { *((volatile int*)__null) = 882; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); } } while ( false); |
| 883 | |
| 884 | int32_t lower = INT32_MIN(-2147483647-1); |
| 885 | int32_t upper = INT32_MAX(2147483647); |
| 886 | |
| 887 | if (lhs->lower() >= 0 && rhs->lower() >= 0) { |
| 888 | // Both operands are non-negative, so the result won't be less than either. |
| 889 | lower = std::max(lhs->lower(), rhs->lower()); |
| 890 | // The result will have leading zeros where both operands have leading |
| 891 | // zeros. CountLeadingZeroes32 of a non-negative int32 will at least be 1 to |
| 892 | // account for the bit of sign. |
| 893 | upper = int32_t(UINT32_MAX(4294967295U) >> std::min(CountLeadingZeroes32(lhs->upper()), |
| 894 | CountLeadingZeroes32(rhs->upper()))); |
| 895 | } else { |
| 896 | // The result will have leading ones where either operand has leading ones. |
| 897 | if (lhs->upper() < 0) { |
| 898 | unsigned leadingOnes = CountLeadingZeroes32(~lhs->lower()); |
| 899 | lower = std::max(lower, ~int32_t(UINT32_MAX(4294967295U) >> leadingOnes)); |
| 900 | upper = -1; |
| 901 | } |
| 902 | if (rhs->upper() < 0) { |
| 903 | unsigned leadingOnes = CountLeadingZeroes32(~rhs->lower()); |
| 904 | lower = std::max(lower, ~int32_t(UINT32_MAX(4294967295U) >> leadingOnes)); |
| 905 | upper = -1; |
| 906 | } |
| 907 | } |
| 908 | |
| 909 | return Range::NewInt32Range(alloc, lower, upper); |
| 910 | } |
| 911 | |
| 912 | Range* Range::xor_(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 913 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 913); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 913; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 914 | MOZ_ASSERT(rhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(rhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(rhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("rhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 914); AnnotateMozCrashReason("MOZ_ASSERT" "(" "rhs->isInt32()" ")"); do { *((volatile int*)__null) = 914; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 915 | int32_t lhsLower = lhs->lower(); |
| 916 | int32_t lhsUpper = lhs->upper(); |
| 917 | int32_t rhsLower = rhs->lower(); |
| 918 | int32_t rhsUpper = rhs->upper(); |
| 919 | bool invertAfter = false; |
| 920 | |
| 921 | // If either operand is negative, bitwise-negate it, and arrange to negate |
| 922 | // the result; ~((~x)^y) == x^y. If both are negative the negations on the |
| 923 | // result cancel each other out; effectively this is (~x)^(~y) == x^y. |
| 924 | // These transformations reduce the number of cases we have to handle below. |
| 925 | if (lhsUpper < 0) { |
| 926 | lhsLower = ~lhsLower; |
| 927 | lhsUpper = ~lhsUpper; |
| 928 | std::swap(lhsLower, lhsUpper); |
| 929 | invertAfter = !invertAfter; |
| 930 | } |
| 931 | if (rhsUpper < 0) { |
| 932 | rhsLower = ~rhsLower; |
| 933 | rhsUpper = ~rhsUpper; |
| 934 | std::swap(rhsLower, rhsUpper); |
| 935 | invertAfter = !invertAfter; |
| 936 | } |
| 937 | |
| 938 | // Handle cases where lhs or rhs is always zero specially, because they're |
| 939 | // easy cases where we can be perfectly precise, and because it protects the |
| 940 | // CountLeadingZeroes32 calls below from seeing 0 operands, which would be |
| 941 | // undefined behavior. |
| 942 | int32_t lower = INT32_MIN(-2147483647-1); |
| 943 | int32_t upper = INT32_MAX(2147483647); |
| 944 | if (lhsLower == 0 && lhsUpper == 0) { |
| 945 | upper = rhsUpper; |
| 946 | lower = rhsLower; |
| 947 | } else if (rhsLower == 0 && rhsUpper == 0) { |
| 948 | upper = lhsUpper; |
| 949 | lower = lhsLower; |
| 950 | } else if (lhsLower >= 0 && rhsLower >= 0) { |
| 951 | // Both operands are non-negative. The result will be non-negative. |
| 952 | lower = 0; |
| 953 | // To compute the upper value, take each operand's upper value and |
| 954 | // set all bits that don't correspond to leading zero bits in the |
| 955 | // other to one. For each one, this gives an upper bound for the |
| 956 | // result, so we can take the minimum between the two. |
| 957 | unsigned lhsLeadingZeros = CountLeadingZeroes32(lhsUpper); |
| 958 | unsigned rhsLeadingZeros = CountLeadingZeroes32(rhsUpper); |
| 959 | upper = std::min(rhsUpper | int32_t(UINT32_MAX(4294967295U) >> lhsLeadingZeros), |
| 960 | lhsUpper | int32_t(UINT32_MAX(4294967295U) >> rhsLeadingZeros)); |
| 961 | } |
| 962 | |
| 963 | // If we bitwise-negated one (but not both) of the operands above, apply the |
| 964 | // bitwise-negate to the result, completing ~((~x)^y) == x^y. |
| 965 | if (invertAfter) { |
| 966 | lower = ~lower; |
| 967 | upper = ~upper; |
| 968 | std::swap(lower, upper); |
| 969 | } |
| 970 | |
| 971 | return Range::NewInt32Range(alloc, lower, upper); |
| 972 | } |
| 973 | |
| 974 | Range* Range::not_(TempAllocator& alloc, const Range* op) { |
| 975 | MOZ_ASSERT(op->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(op->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(op->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("op->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 975); AnnotateMozCrashReason("MOZ_ASSERT" "(" "op->isInt32()" ")"); do { *((volatile int*)__null) = 975; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 976 | return Range::NewInt32Range(alloc, ~op->upper(), ~op->lower()); |
| 977 | } |
| 978 | |
| 979 | Range* Range::mul(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 980 | FractionalPartFlag newCanHaveFractionalPart = FractionalPartFlag( |
| 981 | lhs->canHaveFractionalPart_ || rhs->canHaveFractionalPart_); |
| 982 | |
| 983 | NegativeZeroFlag newMayIncludeNegativeZero = NegativeZeroFlag( |
| 984 | (lhs->canHaveSignBitSet() && rhs->canBeFiniteNonNegative()) || |
| 985 | (rhs->canHaveSignBitSet() && lhs->canBeFiniteNonNegative())); |
| 986 | |
| 987 | uint16_t exponent; |
| 988 | if (!lhs->canBeInfiniteOrNaN() && !rhs->canBeInfiniteOrNaN()) { |
| 989 | // Two finite values. |
| 990 | exponent = lhs->numBits() + rhs->numBits() - 1; |
| 991 | if (exponent > Range::MaxFiniteExponent) { |
| 992 | exponent = Range::IncludesInfinity; |
| 993 | } |
| 994 | } else if (!lhs->canBeNaN() && !rhs->canBeNaN() && |
| 995 | !(lhs->canBeZero() && rhs->canBeInfiniteOrNaN()) && |
| 996 | !(rhs->canBeZero() && lhs->canBeInfiniteOrNaN())) { |
| 997 | // Two values that multiplied together won't produce a NaN. |
| 998 | exponent = Range::IncludesInfinity; |
| 999 | } else { |
| 1000 | // Could be anything. |
| 1001 | exponent = Range::IncludesInfinityAndNaN; |
| 1002 | } |
| 1003 | |
| 1004 | if (MissingAnyInt32Bounds(lhs, rhs)) { |
| 1005 | return new (alloc) |
| 1006 | Range(NoInt32LowerBound, NoInt32UpperBound, newCanHaveFractionalPart, |
| 1007 | newMayIncludeNegativeZero, exponent); |
| 1008 | } |
| 1009 | int64_t a = (int64_t)lhs->lower() * (int64_t)rhs->lower(); |
| 1010 | int64_t b = (int64_t)lhs->lower() * (int64_t)rhs->upper(); |
| 1011 | int64_t c = (int64_t)lhs->upper() * (int64_t)rhs->lower(); |
| 1012 | int64_t d = (int64_t)lhs->upper() * (int64_t)rhs->upper(); |
| 1013 | return new (alloc) |
| 1014 | Range(std::min(std::min(a, b), std::min(c, d)), |
| 1015 | std::max(std::max(a, b), std::max(c, d)), newCanHaveFractionalPart, |
| 1016 | newMayIncludeNegativeZero, exponent); |
| 1017 | } |
| 1018 | |
| 1019 | Range* Range::lsh(TempAllocator& alloc, const Range* lhs, int32_t c) { |
| 1020 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1020); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 1020; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1021 | int32_t shift = c & 0x1f; |
| 1022 | |
| 1023 | // If the shift doesn't loose bits or shift bits into the sign bit, we |
| 1024 | // can simply compute the correct range by shifting. |
| 1025 | if ((int32_t)((uint32_t)lhs->lower() << shift << 1 >> shift >> 1) == |
| 1026 | lhs->lower() && |
| 1027 | (int32_t)((uint32_t)lhs->upper() << shift << 1 >> shift >> 1) == |
| 1028 | lhs->upper()) { |
| 1029 | return Range::NewInt32Range(alloc, uint32_t(lhs->lower()) << shift, |
| 1030 | uint32_t(lhs->upper()) << shift); |
| 1031 | } |
| 1032 | |
| 1033 | return Range::NewInt32Range(alloc, INT32_MIN(-2147483647-1), INT32_MAX(2147483647)); |
| 1034 | } |
| 1035 | |
| 1036 | Range* Range::rsh(TempAllocator& alloc, const Range* lhs, int32_t c) { |
| 1037 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1037); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 1037; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1038 | int32_t shift = c & 0x1f; |
| 1039 | return Range::NewInt32Range(alloc, lhs->lower() >> shift, |
| 1040 | lhs->upper() >> shift); |
| 1041 | } |
| 1042 | |
| 1043 | Range* Range::ursh(TempAllocator& alloc, const Range* lhs, int32_t c) { |
| 1044 | // ursh's left operand is uint32, not int32, but for range analysis we |
| 1045 | // currently approximate it as int32. We assume here that the range has |
| 1046 | // already been adjusted accordingly by our callers. |
| 1047 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1047); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 1047; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1048 | |
| 1049 | int32_t shift = c & 0x1f; |
| 1050 | |
| 1051 | // If the value is always non-negative or always negative, we can simply |
| 1052 | // compute the correct range by shifting. |
| 1053 | if (lhs->isFiniteNonNegative() || lhs->isFiniteNegative()) { |
| 1054 | return Range::NewUInt32Range(alloc, uint32_t(lhs->lower()) >> shift, |
| 1055 | uint32_t(lhs->upper()) >> shift); |
| 1056 | } |
| 1057 | |
| 1058 | // Otherwise return the most general range after the shift. |
| 1059 | return Range::NewUInt32Range(alloc, 0, UINT32_MAX(4294967295U) >> shift); |
| 1060 | } |
| 1061 | |
| 1062 | Range* Range::lsh(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 1063 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1063); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 1063; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1064 | MOZ_ASSERT(rhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(rhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(rhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("rhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1064); AnnotateMozCrashReason("MOZ_ASSERT" "(" "rhs->isInt32()" ")"); do { *((volatile int*)__null) = 1064; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1065 | return Range::NewInt32Range(alloc, INT32_MIN(-2147483647-1), INT32_MAX(2147483647)); |
| 1066 | } |
| 1067 | |
| 1068 | Range* Range::rsh(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 1069 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1069); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 1069; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1070 | MOZ_ASSERT(rhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(rhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(rhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("rhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1070); AnnotateMozCrashReason("MOZ_ASSERT" "(" "rhs->isInt32()" ")"); do { *((volatile int*)__null) = 1070; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1071 | |
| 1072 | // Canonicalize the shift range to 0 to 31. |
| 1073 | int32_t shiftLower = rhs->lower(); |
| 1074 | int32_t shiftUpper = rhs->upper(); |
| 1075 | if ((int64_t(shiftUpper) - int64_t(shiftLower)) >= 31) { |
| 1076 | shiftLower = 0; |
| 1077 | shiftUpper = 31; |
| 1078 | } else { |
| 1079 | shiftLower &= 0x1f; |
| 1080 | shiftUpper &= 0x1f; |
| 1081 | if (shiftLower > shiftUpper) { |
| 1082 | shiftLower = 0; |
| 1083 | shiftUpper = 31; |
| 1084 | } |
| 1085 | } |
| 1086 | MOZ_ASSERT(shiftLower >= 0 && shiftUpper <= 31)do { static_assert( mozilla::detail::AssertionConditionType< decltype(shiftLower >= 0 && shiftUpper <= 31)> ::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(shiftLower >= 0 && shiftUpper <= 31))) , 0))) { do { } while (false); MOZ_ReportAssertionFailure("shiftLower >= 0 && shiftUpper <= 31" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1086); AnnotateMozCrashReason("MOZ_ASSERT" "(" "shiftLower >= 0 && shiftUpper <= 31" ")"); do { *((volatile int*)__null) = 1086; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1087 | |
| 1088 | // The lhs bounds are signed, thus the minimum is either the lower bound |
| 1089 | // shift by the smallest shift if negative or the lower bound shifted by the |
| 1090 | // biggest shift otherwise. And the opposite for the maximum. |
| 1091 | int32_t lhsLower = lhs->lower(); |
| 1092 | int32_t min = lhsLower < 0 ? lhsLower >> shiftLower : lhsLower >> shiftUpper; |
| 1093 | int32_t lhsUpper = lhs->upper(); |
| 1094 | int32_t max = lhsUpper >= 0 ? lhsUpper >> shiftLower : lhsUpper >> shiftUpper; |
| 1095 | |
| 1096 | return Range::NewInt32Range(alloc, min, max); |
| 1097 | } |
| 1098 | |
| 1099 | Range* Range::ursh(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 1100 | // ursh's left operand is uint32, not int32, but for range analysis we |
| 1101 | // currently approximate it as int32. We assume here that the range has |
| 1102 | // already been adjusted accordingly by our callers. |
| 1103 | MOZ_ASSERT(lhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(lhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(lhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("lhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1103); AnnotateMozCrashReason("MOZ_ASSERT" "(" "lhs->isInt32()" ")"); do { *((volatile int*)__null) = 1103; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1104 | MOZ_ASSERT(rhs->isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(rhs->isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(rhs->isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("rhs->isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1104); AnnotateMozCrashReason("MOZ_ASSERT" "(" "rhs->isInt32()" ")"); do { *((volatile int*)__null) = 1104; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1105 | return Range::NewUInt32Range( |
| 1106 | alloc, 0, lhs->isFiniteNonNegative() ? lhs->upper() : UINT32_MAX(4294967295U)); |
| 1107 | } |
| 1108 | |
| 1109 | Range* Range::abs(TempAllocator& alloc, const Range* op) { |
| 1110 | int32_t l = op->lower_; |
| 1111 | int32_t u = op->upper_; |
| 1112 | FractionalPartFlag canHaveFractionalPart = op->canHaveFractionalPart_; |
| 1113 | |
| 1114 | // Abs never produces a negative zero. |
| 1115 | NegativeZeroFlag canBeNegativeZero = ExcludesNegativeZero; |
| 1116 | |
| 1117 | return new (alloc) Range( |
| 1118 | std::max(std::max(int32_t(0), l), u == INT32_MIN(-2147483647-1) ? INT32_MAX(2147483647) : -u), true, |
| 1119 | std::max(std::max(int32_t(0), u), l == INT32_MIN(-2147483647-1) ? INT32_MAX(2147483647) : -l), |
| 1120 | op->hasInt32Bounds() && l != INT32_MIN(-2147483647-1), canHaveFractionalPart, |
| 1121 | canBeNegativeZero, op->max_exponent_); |
| 1122 | } |
| 1123 | |
| 1124 | Range* Range::min(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 1125 | // If either operand is NaN, the result is NaN. |
| 1126 | if (lhs->canBeNaN() || rhs->canBeNaN()) { |
| 1127 | return nullptr; |
| 1128 | } |
| 1129 | |
| 1130 | FractionalPartFlag newCanHaveFractionalPart = FractionalPartFlag( |
| 1131 | lhs->canHaveFractionalPart_ || rhs->canHaveFractionalPart_); |
| 1132 | NegativeZeroFlag newMayIncludeNegativeZero = |
| 1133 | NegativeZeroFlag(lhs->canBeNegativeZero_ || rhs->canBeNegativeZero_); |
| 1134 | |
| 1135 | return new (alloc) Range(std::min(lhs->lower_, rhs->lower_), |
| 1136 | lhs->hasInt32LowerBound_ && rhs->hasInt32LowerBound_, |
| 1137 | std::min(lhs->upper_, rhs->upper_), |
| 1138 | lhs->hasInt32UpperBound_ || rhs->hasInt32UpperBound_, |
| 1139 | newCanHaveFractionalPart, newMayIncludeNegativeZero, |
| 1140 | std::max(lhs->max_exponent_, rhs->max_exponent_)); |
| 1141 | } |
| 1142 | |
| 1143 | Range* Range::max(TempAllocator& alloc, const Range* lhs, const Range* rhs) { |
| 1144 | // If either operand is NaN, the result is NaN. |
| 1145 | if (lhs->canBeNaN() || rhs->canBeNaN()) { |
| 1146 | return nullptr; |
| 1147 | } |
| 1148 | |
| 1149 | FractionalPartFlag newCanHaveFractionalPart = FractionalPartFlag( |
| 1150 | lhs->canHaveFractionalPart_ || rhs->canHaveFractionalPart_); |
| 1151 | NegativeZeroFlag newMayIncludeNegativeZero = |
| 1152 | NegativeZeroFlag(lhs->canBeNegativeZero_ || rhs->canBeNegativeZero_); |
| 1153 | |
| 1154 | return new (alloc) Range(std::max(lhs->lower_, rhs->lower_), |
| 1155 | lhs->hasInt32LowerBound_ || rhs->hasInt32LowerBound_, |
| 1156 | std::max(lhs->upper_, rhs->upper_), |
| 1157 | lhs->hasInt32UpperBound_ && rhs->hasInt32UpperBound_, |
| 1158 | newCanHaveFractionalPart, newMayIncludeNegativeZero, |
| 1159 | std::max(lhs->max_exponent_, rhs->max_exponent_)); |
| 1160 | } |
| 1161 | |
| 1162 | Range* Range::floor(TempAllocator& alloc, const Range* op) { |
| 1163 | Range* copy = new (alloc) Range(*op); |
| 1164 | // Decrement lower bound of copy range if op have a factional part and lower |
| 1165 | // bound is Int32 defined. Also we avoid to decrement when op have a |
| 1166 | // fractional part but lower_ >= JSVAL_INT_MAX. |
| 1167 | if (op->canHaveFractionalPart() && op->hasInt32LowerBound()) { |
| 1168 | copy->setLowerInit(int64_t(copy->lower_) - 1); |
| 1169 | } |
| 1170 | |
| 1171 | // Also refine max_exponent_ because floor may have decremented int value |
| 1172 | // If we've got int32 defined bounds, just deduce it using defined bounds. |
| 1173 | // But, if we don't have those, value's max_exponent_ may have changed. |
| 1174 | // Because we're looking to maintain an over estimation, if we can, |
| 1175 | // we increment it. |
| 1176 | if (copy->hasInt32Bounds()) |
| 1177 | copy->max_exponent_ = copy->exponentImpliedByInt32Bounds(); |
| 1178 | else if (copy->max_exponent_ < MaxFiniteExponent) |
| 1179 | copy->max_exponent_++; |
| 1180 | |
| 1181 | copy->canHaveFractionalPart_ = ExcludesFractionalParts; |
| 1182 | copy->assertInvariants(); |
| 1183 | return copy; |
| 1184 | } |
| 1185 | |
| 1186 | Range* Range::ceil(TempAllocator& alloc, const Range* op) { |
| 1187 | Range* copy = new (alloc) Range(*op); |
| 1188 | |
| 1189 | // We need to refine max_exponent_ because ceil may have incremented the int |
| 1190 | // value. If we have got int32 bounds defined, just deduce it using the |
| 1191 | // defined bounds. Else we can just increment its value, as we are looking to |
| 1192 | // maintain an over estimation. |
| 1193 | if (copy->hasInt32Bounds()) { |
| 1194 | copy->max_exponent_ = copy->exponentImpliedByInt32Bounds(); |
| 1195 | } else if (copy->max_exponent_ < MaxFiniteExponent) { |
| 1196 | copy->max_exponent_++; |
| 1197 | } |
| 1198 | |
| 1199 | // If the range is definitely above 0 or below -1, we don't need to include |
| 1200 | // -0; otherwise we do. |
| 1201 | |
| 1202 | copy->canBeNegativeZero_ = ((copy->lower_ > 0) || (copy->upper_ <= -1)) |
| 1203 | ? copy->canBeNegativeZero_ |
| 1204 | : IncludesNegativeZero; |
| 1205 | |
| 1206 | copy->canHaveFractionalPart_ = ExcludesFractionalParts; |
| 1207 | copy->assertInvariants(); |
| 1208 | return copy; |
| 1209 | } |
| 1210 | |
| 1211 | Range* Range::sign(TempAllocator& alloc, const Range* op) { |
| 1212 | if (op->canBeNaN()) { |
| 1213 | return nullptr; |
| 1214 | } |
| 1215 | |
| 1216 | return new (alloc) Range(std::max(std::min(op->lower_, 1), -1), |
| 1217 | std::max(std::min(op->upper_, 1), -1), |
| 1218 | Range::ExcludesFractionalParts, |
| 1219 | NegativeZeroFlag(op->canBeNegativeZero()), 0); |
| 1220 | } |
| 1221 | |
| 1222 | Range* Range::NaNToZero(TempAllocator& alloc, const Range* op) { |
| 1223 | Range* copy = new (alloc) Range(*op); |
| 1224 | if (copy->canBeNaN()) { |
| 1225 | copy->max_exponent_ = Range::IncludesInfinity; |
| 1226 | if (!copy->canBeZero()) { |
| 1227 | Range zero; |
| 1228 | zero.setDoubleSingleton(0); |
| 1229 | copy->unionWith(&zero); |
| 1230 | } |
| 1231 | } |
| 1232 | copy->refineToExcludeNegativeZero(); |
| 1233 | return copy; |
| 1234 | } |
| 1235 | |
| 1236 | bool Range::negativeZeroMul(const Range* lhs, const Range* rhs) { |
| 1237 | // The result can only be negative zero if both sides are finite and they |
| 1238 | // have differing signs. |
| 1239 | return (lhs->canHaveSignBitSet() && rhs->canBeFiniteNonNegative()) || |
| 1240 | (rhs->canHaveSignBitSet() && lhs->canBeFiniteNonNegative()); |
| 1241 | } |
| 1242 | |
| 1243 | bool Range::update(const Range* other) { |
| 1244 | bool changed = lower_ != other->lower_ || |
| 1245 | hasInt32LowerBound_ != other->hasInt32LowerBound_ || |
| 1246 | upper_ != other->upper_ || |
| 1247 | hasInt32UpperBound_ != other->hasInt32UpperBound_ || |
| 1248 | canHaveFractionalPart_ != other->canHaveFractionalPart_ || |
| 1249 | canBeNegativeZero_ != other->canBeNegativeZero_ || |
| 1250 | max_exponent_ != other->max_exponent_; |
| 1251 | if (changed) { |
| 1252 | lower_ = other->lower_; |
| 1253 | hasInt32LowerBound_ = other->hasInt32LowerBound_; |
| 1254 | upper_ = other->upper_; |
| 1255 | hasInt32UpperBound_ = other->hasInt32UpperBound_; |
| 1256 | canHaveFractionalPart_ = other->canHaveFractionalPart_; |
| 1257 | canBeNegativeZero_ = other->canBeNegativeZero_; |
| 1258 | max_exponent_ = other->max_exponent_; |
| 1259 | assertInvariants(); |
| 1260 | } |
| 1261 | |
| 1262 | return changed; |
| 1263 | } |
| 1264 | |
| 1265 | /////////////////////////////////////////////////////////////////////////////// |
| 1266 | // Range Computation for MIR Nodes |
| 1267 | /////////////////////////////////////////////////////////////////////////////// |
| 1268 | |
| 1269 | void MPhi::computeRange(TempAllocator& alloc) { |
| 1270 | if (type() != MIRType::Int32 && type() != MIRType::Double) { |
| 1271 | return; |
| 1272 | } |
| 1273 | |
| 1274 | Range* range = nullptr; |
| 1275 | for (size_t i = 0, e = numOperands(); i < e; i++) { |
| 1276 | if (getOperand(i)->block()->unreachable()) { |
| 1277 | JitSpew(JitSpew_Range, "Ignoring unreachable input %u", |
| 1278 | getOperand(i)->id()); |
| 1279 | continue; |
| 1280 | } |
| 1281 | |
| 1282 | // Peek at the pre-bailout range so we can take a short-cut; if any of |
| 1283 | // the operands has an unknown range, this phi has an unknown range. |
| 1284 | if (!getOperand(i)->range()) { |
| 1285 | return; |
| 1286 | } |
| 1287 | |
| 1288 | Range input(getOperand(i)); |
| 1289 | |
| 1290 | if (range) { |
| 1291 | range->unionWith(&input); |
| 1292 | } else { |
| 1293 | range = new (alloc) Range(input); |
| 1294 | } |
| 1295 | } |
| 1296 | |
| 1297 | setRange(range); |
| 1298 | } |
| 1299 | |
| 1300 | void MBeta::computeRange(TempAllocator& alloc) { |
| 1301 | bool emptyRange = false; |
| 1302 | |
| 1303 | Range opRange(getOperand(0)); |
| 1304 | Range* range = Range::intersect(alloc, &opRange, comparison_, &emptyRange); |
| 1305 | if (emptyRange) { |
| 1306 | JitSpew(JitSpew_Range, "Marking block for inst %u unreachable", id()); |
| 1307 | block()->setUnreachableUnchecked(); |
| 1308 | } else { |
| 1309 | setRange(range); |
| 1310 | } |
| 1311 | } |
| 1312 | |
| 1313 | void MConstant::computeRange(TempAllocator& alloc) { |
| 1314 | if (isTypeRepresentableAsDouble()) { |
| 1315 | double d = numberToDouble(); |
| 1316 | setRange(Range::NewDoubleSingletonRange(alloc, d)); |
| 1317 | } else if (type() == MIRType::Boolean) { |
| 1318 | bool b = toBoolean(); |
| 1319 | setRange(Range::NewInt32Range(alloc, b, b)); |
| 1320 | } |
| 1321 | } |
| 1322 | |
| 1323 | void MCharCodeAt::computeRange(TempAllocator& alloc) { |
| 1324 | // ECMA 262 says that the integer will be non-negative and at most 65535. |
| 1325 | setRange(Range::NewInt32Range(alloc, 0, unicode::UTF16Max)); |
| 1326 | } |
| 1327 | |
| 1328 | void MCodePointAt::computeRange(TempAllocator& alloc) { |
| 1329 | setRange(Range::NewInt32Range(alloc, 0, unicode::NonBMPMax)); |
| 1330 | } |
| 1331 | |
| 1332 | void MClampToUint8::computeRange(TempAllocator& alloc) { |
| 1333 | setRange(Range::NewUInt32Range(alloc, 0, 255)); |
| 1334 | } |
| 1335 | |
| 1336 | void MBitAnd::computeRange(TempAllocator& alloc) { |
| 1337 | if (type() != MIRType::Int32) { |
| 1338 | return; |
| 1339 | } |
| 1340 | |
| 1341 | Range left(getOperand(0)); |
| 1342 | Range right(getOperand(1)); |
| 1343 | left.wrapAroundToInt32(); |
| 1344 | right.wrapAroundToInt32(); |
| 1345 | |
| 1346 | setRange(Range::and_(alloc, &left, &right)); |
| 1347 | } |
| 1348 | |
| 1349 | void MBitOr::computeRange(TempAllocator& alloc) { |
| 1350 | if (type() != MIRType::Int32) { |
| 1351 | return; |
| 1352 | } |
| 1353 | |
| 1354 | Range left(getOperand(0)); |
| 1355 | Range right(getOperand(1)); |
| 1356 | left.wrapAroundToInt32(); |
| 1357 | right.wrapAroundToInt32(); |
| 1358 | |
| 1359 | setRange(Range::or_(alloc, &left, &right)); |
| 1360 | } |
| 1361 | |
| 1362 | void MBitXor::computeRange(TempAllocator& alloc) { |
| 1363 | if (type() != MIRType::Int32) { |
| 1364 | return; |
| 1365 | } |
| 1366 | |
| 1367 | Range left(getOperand(0)); |
| 1368 | Range right(getOperand(1)); |
| 1369 | left.wrapAroundToInt32(); |
| 1370 | right.wrapAroundToInt32(); |
| 1371 | |
| 1372 | setRange(Range::xor_(alloc, &left, &right)); |
| 1373 | } |
| 1374 | |
| 1375 | void MBitNot::computeRange(TempAllocator& alloc) { |
| 1376 | if (type() == MIRType::Int64) { |
| 1377 | return; |
| 1378 | } |
| 1379 | MOZ_ASSERT(type() == MIRType::Int32)do { static_assert( mozilla::detail::AssertionConditionType< decltype(type() == MIRType::Int32)>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(type() == MIRType::Int32))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("type() == MIRType::Int32" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1379); AnnotateMozCrashReason("MOZ_ASSERT" "(" "type() == MIRType::Int32" ")"); do { *((volatile int*)__null) = 1379; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1380 | |
| 1381 | Range op(getOperand(0)); |
| 1382 | op.wrapAroundToInt32(); |
| 1383 | |
| 1384 | setRange(Range::not_(alloc, &op)); |
| 1385 | } |
| 1386 | |
| 1387 | void MLsh::computeRange(TempAllocator& alloc) { |
| 1388 | if (type() != MIRType::Int32) { |
| 1389 | return; |
| 1390 | } |
| 1391 | |
| 1392 | Range left(getOperand(0)); |
| 1393 | Range right(getOperand(1)); |
| 1394 | left.wrapAroundToInt32(); |
| 1395 | |
| 1396 | MConstant* rhsConst = getOperand(1)->maybeConstantValue(); |
| 1397 | if (rhsConst && rhsConst->type() == MIRType::Int32) { |
| 1398 | int32_t c = rhsConst->toInt32(); |
| 1399 | setRange(Range::lsh(alloc, &left, c)); |
| 1400 | return; |
| 1401 | } |
| 1402 | |
| 1403 | right.wrapAroundToShiftCount(); |
| 1404 | setRange(Range::lsh(alloc, &left, &right)); |
| 1405 | } |
| 1406 | |
| 1407 | void MRsh::computeRange(TempAllocator& alloc) { |
| 1408 | if (type() != MIRType::Int32) { |
| 1409 | return; |
| 1410 | } |
| 1411 | |
| 1412 | Range left(getOperand(0)); |
| 1413 | Range right(getOperand(1)); |
| 1414 | left.wrapAroundToInt32(); |
| 1415 | |
| 1416 | MConstant* rhsConst = getOperand(1)->maybeConstantValue(); |
| 1417 | if (rhsConst && rhsConst->type() == MIRType::Int32) { |
| 1418 | int32_t c = rhsConst->toInt32(); |
| 1419 | setRange(Range::rsh(alloc, &left, c)); |
| 1420 | return; |
| 1421 | } |
| 1422 | |
| 1423 | right.wrapAroundToShiftCount(); |
| 1424 | setRange(Range::rsh(alloc, &left, &right)); |
| 1425 | } |
| 1426 | |
| 1427 | void MUrsh::computeRange(TempAllocator& alloc) { |
| 1428 | if (type() != MIRType::Int32) { |
| 1429 | return; |
| 1430 | } |
| 1431 | |
| 1432 | Range left(getOperand(0)); |
| 1433 | Range right(getOperand(1)); |
| 1434 | |
| 1435 | // ursh can be thought of as converting its left operand to uint32, or it |
| 1436 | // can be thought of as converting its left operand to int32, and then |
| 1437 | // reinterpreting the int32 bits as a uint32 value. Both approaches yield |
| 1438 | // the same result. Since we lack support for full uint32 ranges, we use |
| 1439 | // the second interpretation, though it does cause us to be conservative. |
| 1440 | left.wrapAroundToInt32(); |
| 1441 | right.wrapAroundToShiftCount(); |
| 1442 | |
| 1443 | MConstant* rhsConst = getOperand(1)->maybeConstantValue(); |
| 1444 | if (rhsConst && rhsConst->type() == MIRType::Int32) { |
| 1445 | int32_t c = rhsConst->toInt32(); |
| 1446 | setRange(Range::ursh(alloc, &left, c)); |
| 1447 | } else { |
| 1448 | setRange(Range::ursh(alloc, &left, &right)); |
| 1449 | } |
| 1450 | |
| 1451 | MOZ_ASSERT(range()->lower() >= 0)do { static_assert( mozilla::detail::AssertionConditionType< decltype(range()->lower() >= 0)>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(range()->lower() >= 0) )), 0))) { do { } while (false); MOZ_ReportAssertionFailure("range()->lower() >= 0" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1451); AnnotateMozCrashReason("MOZ_ASSERT" "(" "range()->lower() >= 0" ")"); do { *((volatile int*)__null) = 1451; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1452 | } |
| 1453 | |
| 1454 | void MAbs::computeRange(TempAllocator& alloc) { |
| 1455 | if (type() != MIRType::Int32 && type() != MIRType::Double) { |
| 1456 | return; |
| 1457 | } |
| 1458 | |
| 1459 | Range other(getOperand(0)); |
| 1460 | Range* next = Range::abs(alloc, &other); |
| 1461 | if (implicitTruncate_) { |
| 1462 | next->wrapAroundToInt32(); |
| 1463 | } |
| 1464 | setRange(next); |
| 1465 | } |
| 1466 | |
| 1467 | void MFloor::computeRange(TempAllocator& alloc) { |
| 1468 | Range other(getOperand(0)); |
| 1469 | setRange(Range::floor(alloc, &other)); |
| 1470 | } |
| 1471 | |
| 1472 | void MCeil::computeRange(TempAllocator& alloc) { |
| 1473 | Range other(getOperand(0)); |
| 1474 | setRange(Range::ceil(alloc, &other)); |
| 1475 | } |
| 1476 | |
| 1477 | void MClz::computeRange(TempAllocator& alloc) { |
| 1478 | if (type() != MIRType::Int32) { |
| 1479 | return; |
| 1480 | } |
| 1481 | setRange(Range::NewUInt32Range(alloc, 0, 32)); |
| 1482 | } |
| 1483 | |
| 1484 | void MCtz::computeRange(TempAllocator& alloc) { |
| 1485 | if (type() != MIRType::Int32) { |
| 1486 | return; |
| 1487 | } |
| 1488 | setRange(Range::NewUInt32Range(alloc, 0, 32)); |
| 1489 | } |
| 1490 | |
| 1491 | void MPopcnt::computeRange(TempAllocator& alloc) { |
| 1492 | if (type() != MIRType::Int32) { |
| 1493 | return; |
| 1494 | } |
| 1495 | setRange(Range::NewUInt32Range(alloc, 0, 32)); |
| 1496 | } |
| 1497 | |
| 1498 | void MMinMax::computeRange(TempAllocator& alloc) { |
| 1499 | if (type() != MIRType::Int32 && type() != MIRType::Double) { |
| 1500 | return; |
| 1501 | } |
| 1502 | |
| 1503 | Range left(getOperand(0)); |
| 1504 | Range right(getOperand(1)); |
| 1505 | setRange(isMax() ? Range::max(alloc, &left, &right) |
| 1506 | : Range::min(alloc, &left, &right)); |
| 1507 | } |
| 1508 | |
| 1509 | void MAdd::computeRange(TempAllocator& alloc) { |
| 1510 | if (type() != MIRType::Int32 && type() != MIRType::Double) { |
| 1511 | return; |
| 1512 | } |
| 1513 | Range left(getOperand(0)); |
| 1514 | Range right(getOperand(1)); |
| 1515 | Range* next = Range::add(alloc, &left, &right); |
| 1516 | if (isTruncated()) { |
| 1517 | next->wrapAroundToInt32(); |
| 1518 | } |
| 1519 | setRange(next); |
| 1520 | } |
| 1521 | |
| 1522 | void MSub::computeRange(TempAllocator& alloc) { |
| 1523 | if (type() != MIRType::Int32 && type() != MIRType::Double) { |
| 1524 | return; |
| 1525 | } |
| 1526 | Range left(getOperand(0)); |
| 1527 | Range right(getOperand(1)); |
| 1528 | Range* next = Range::sub(alloc, &left, &right); |
| 1529 | if (isTruncated()) { |
| 1530 | next->wrapAroundToInt32(); |
| 1531 | } |
| 1532 | setRange(next); |
| 1533 | } |
| 1534 | |
| 1535 | void MMul::computeRange(TempAllocator& alloc) { |
| 1536 | if (type() != MIRType::Int32 && type() != MIRType::Double) { |
| 1537 | return; |
| 1538 | } |
| 1539 | Range left(getOperand(0)); |
| 1540 | Range right(getOperand(1)); |
| 1541 | if (canBeNegativeZero()) { |
| 1542 | canBeNegativeZero_ = Range::negativeZeroMul(&left, &right); |
| 1543 | } |
| 1544 | Range* next = Range::mul(alloc, &left, &right); |
| 1545 | if (!next->canBeNegativeZero()) { |
| 1546 | canBeNegativeZero_ = false; |
| 1547 | } |
| 1548 | // Truncated multiplications could overflow in both directions |
| 1549 | if (isTruncated()) { |
| 1550 | next->wrapAroundToInt32(); |
| 1551 | } |
| 1552 | setRange(next); |
| 1553 | } |
| 1554 | |
| 1555 | void MMod::computeRange(TempAllocator& alloc) { |
| 1556 | if (type() != MIRType::Int32 && type() != MIRType::Double) { |
| 1557 | return; |
| 1558 | } |
| 1559 | Range lhs(getOperand(0)); |
| 1560 | Range rhs(getOperand(1)); |
| 1561 | |
| 1562 | // If either operand is a NaN, the result is NaN. This also conservatively |
| 1563 | // handles Infinity cases. |
| 1564 | if (!lhs.hasInt32Bounds() || !rhs.hasInt32Bounds()) { |
| 1565 | return; |
| 1566 | } |
| 1567 | |
| 1568 | // If RHS can be zero, the result can be NaN. |
| 1569 | if (rhs.lower() <= 0 && rhs.upper() >= 0) { |
| 1570 | return; |
| 1571 | } |
| 1572 | |
| 1573 | // If both operands are non-negative integers, we can optimize this to an |
| 1574 | // unsigned mod. |
| 1575 | if (type() == MIRType::Int32 && rhs.lower() > 0) { |
| 1576 | bool hasDoubles = lhs.lower() < 0 || lhs.canHaveFractionalPart() || |
| 1577 | rhs.canHaveFractionalPart(); |
| 1578 | // It is not possible to check that lhs.lower() >= 0, since the range |
| 1579 | // of a ursh with rhs a 0 constant is wrapped around the int32 range in |
| 1580 | // Range::Range(). However, IsUint32Type() will only return true for |
| 1581 | // nodes that lie in the range [0, UINT32_MAX]. |
| 1582 | bool hasUint32s = |
| 1583 | IsUint32Type(getOperand(0)) && |
| 1584 | getOperand(1)->type() == MIRType::Int32 && |
| 1585 | (IsUint32Type(getOperand(1)) || getOperand(1)->isConstant()); |
| 1586 | if (!hasDoubles || hasUint32s) { |
| 1587 | unsigned_ = true; |
| 1588 | } |
| 1589 | } |
| 1590 | |
| 1591 | // For unsigned mod, we have to convert both operands to unsigned. |
| 1592 | // Note that we handled the case of a zero rhs above. |
| 1593 | if (unsigned_) { |
| 1594 | // The result of an unsigned mod will never be unsigned-greater than |
| 1595 | // either operand. |
| 1596 | uint32_t lhsBound = std::max<uint32_t>(lhs.lower(), lhs.upper()); |
| 1597 | uint32_t rhsBound = std::max<uint32_t>(rhs.lower(), rhs.upper()); |
| 1598 | |
| 1599 | // If either range crosses through -1 as a signed value, it could be |
| 1600 | // the maximum unsigned value when interpreted as unsigned. If the range |
| 1601 | // doesn't include -1, then the simple max value we computed above is |
| 1602 | // correct. |
| 1603 | if (lhs.lower() <= -1 && lhs.upper() >= -1) { |
| 1604 | lhsBound = UINT32_MAX(4294967295U); |
| 1605 | } |
| 1606 | if (rhs.lower() <= -1 && rhs.upper() >= -1) { |
| 1607 | rhsBound = UINT32_MAX(4294967295U); |
| 1608 | } |
| 1609 | |
| 1610 | // The result will never be equal to the rhs, and we shouldn't have |
| 1611 | // any rounding to worry about. |
| 1612 | MOZ_ASSERT(!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart())do { static_assert( mozilla::detail::AssertionConditionType< decltype(!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart ())>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart ()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1612); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart()" ")"); do { *((volatile int*)__null) = 1612; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1613 | --rhsBound; |
| 1614 | |
| 1615 | // This gives us two upper bounds, so we can take the best one. |
| 1616 | setRange(Range::NewUInt32Range(alloc, 0, std::min(lhsBound, rhsBound))); |
| 1617 | return; |
| 1618 | } |
| 1619 | |
| 1620 | // Math.abs(lhs % rhs) == Math.abs(lhs) % Math.abs(rhs). |
| 1621 | // First, the absolute value of the result will always be less than the |
| 1622 | // absolute value of rhs. (And if rhs is zero, the result is NaN). |
| 1623 | int64_t a = Abs<int64_t>(rhs.lower()); |
| 1624 | int64_t b = Abs<int64_t>(rhs.upper()); |
| 1625 | if (a == 0 && b == 0) { |
| 1626 | return; |
| 1627 | } |
| 1628 | int64_t rhsAbsBound = std::max(a, b); |
| 1629 | |
| 1630 | // If the value is known to be integer, less-than abs(rhs) is equivalent |
| 1631 | // to less-than-or-equal abs(rhs)-1. This is important for being able to |
| 1632 | // say that the result of x%256 is an 8-bit unsigned number. |
| 1633 | if (!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart()) { |
| 1634 | --rhsAbsBound; |
| 1635 | } |
| 1636 | |
| 1637 | // Next, the absolute value of the result will never be greater than the |
| 1638 | // absolute value of lhs. |
| 1639 | int64_t lhsAbsBound = |
| 1640 | std::max(Abs<int64_t>(lhs.lower()), Abs<int64_t>(lhs.upper())); |
| 1641 | |
| 1642 | // This gives us two upper bounds, so we can take the best one. |
| 1643 | int64_t absBound = std::min(lhsAbsBound, rhsAbsBound); |
| 1644 | |
| 1645 | // Now consider the sign of the result. |
| 1646 | // If lhs is non-negative, the result will be non-negative. |
| 1647 | // If lhs is non-positive, the result will be non-positive. |
| 1648 | int64_t lower = lhs.lower() >= 0 ? 0 : -absBound; |
| 1649 | int64_t upper = lhs.upper() <= 0 ? 0 : absBound; |
| 1650 | |
| 1651 | Range::FractionalPartFlag newCanHaveFractionalPart = |
| 1652 | Range::FractionalPartFlag(lhs.canHaveFractionalPart() || |
| 1653 | rhs.canHaveFractionalPart()); |
| 1654 | |
| 1655 | // If the lhs can have the sign bit set and we can return a zero, it'll be a |
| 1656 | // negative zero. |
| 1657 | Range::NegativeZeroFlag newMayIncludeNegativeZero = |
| 1658 | Range::NegativeZeroFlag(lhs.canHaveSignBitSet()); |
| 1659 | |
| 1660 | setRange(new (alloc) Range(lower, upper, newCanHaveFractionalPart, |
| 1661 | newMayIncludeNegativeZero, |
| 1662 | std::min(lhs.exponent(), rhs.exponent()))); |
| 1663 | } |
| 1664 | |
| 1665 | void MDiv::computeRange(TempAllocator& alloc) { |
| 1666 | if (type() != MIRType::Int32 && type() != MIRType::Double) { |
| 1667 | return; |
| 1668 | } |
| 1669 | Range lhs(getOperand(0)); |
| 1670 | Range rhs(getOperand(1)); |
| 1671 | |
| 1672 | // If either operand is a NaN, the result is NaN. This also conservatively |
| 1673 | // handles Infinity cases. |
| 1674 | if (!lhs.hasInt32Bounds() || !rhs.hasInt32Bounds()) { |
| 1675 | return; |
| 1676 | } |
| 1677 | |
| 1678 | // Something simple for now: When dividing by a positive rhs, the result |
| 1679 | // won't be further from zero than lhs. |
| 1680 | if (lhs.lower() >= 0 && rhs.lower() >= 1) { |
| 1681 | setRange(new (alloc) Range(0, lhs.upper(), Range::IncludesFractionalParts, |
| 1682 | Range::IncludesNegativeZero, lhs.exponent())); |
| 1683 | } else if (unsigned_ && rhs.lower() >= 1) { |
| 1684 | // We shouldn't set the unsigned flag if the inputs can have |
| 1685 | // fractional parts. |
| 1686 | MOZ_ASSERT(!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart())do { static_assert( mozilla::detail::AssertionConditionType< decltype(!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart ())>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart ()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1686); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!lhs.canHaveFractionalPart() && !rhs.canHaveFractionalPart()" ")"); do { *((volatile int*)__null) = 1686; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1687 | // We shouldn't set the unsigned flag if the inputs can be |
| 1688 | // negative zero. |
| 1689 | MOZ_ASSERT(!lhs.canBeNegativeZero() && !rhs.canBeNegativeZero())do { static_assert( mozilla::detail::AssertionConditionType< decltype(!lhs.canBeNegativeZero() && !rhs.canBeNegativeZero ())>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(!lhs.canBeNegativeZero() && !rhs.canBeNegativeZero ()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("!lhs.canBeNegativeZero() && !rhs.canBeNegativeZero()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1689); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!lhs.canBeNegativeZero() && !rhs.canBeNegativeZero()" ")"); do { *((volatile int*)__null) = 1689; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1690 | // Unsigned division by a non-zero rhs will return a uint32 value. |
| 1691 | setRange(Range::NewUInt32Range(alloc, 0, UINT32_MAX(4294967295U))); |
| 1692 | } |
| 1693 | } |
| 1694 | |
| 1695 | void MSqrt::computeRange(TempAllocator& alloc) { |
| 1696 | Range input(getOperand(0)); |
| 1697 | |
| 1698 | // If either operand is a NaN, the result is NaN. This also conservatively |
| 1699 | // handles Infinity cases. |
| 1700 | if (!input.hasInt32Bounds()) { |
| 1701 | return; |
| 1702 | } |
| 1703 | |
| 1704 | // Sqrt of a negative non-zero value is NaN. |
| 1705 | if (input.lower() < 0) { |
| 1706 | return; |
| 1707 | } |
| 1708 | |
| 1709 | // Something simple for now: When taking the sqrt of a positive value, the |
| 1710 | // result won't be further from zero than the input. |
| 1711 | // And, sqrt of an integer may have a fractional part. |
| 1712 | setRange(new (alloc) Range(0, input.upper(), Range::IncludesFractionalParts, |
| 1713 | input.canBeNegativeZero(), input.exponent())); |
| 1714 | } |
| 1715 | |
| 1716 | void MToDouble::computeRange(TempAllocator& alloc) { |
| 1717 | setRange(new (alloc) Range(getOperand(0))); |
| 1718 | } |
| 1719 | |
| 1720 | void MToFloat32::computeRange(TempAllocator& alloc) {} |
| 1721 | |
| 1722 | void MTruncateToInt32::computeRange(TempAllocator& alloc) { |
| 1723 | Range* output = new (alloc) Range(getOperand(0)); |
| 1724 | output->wrapAroundToInt32(); |
| 1725 | setRange(output); |
| 1726 | } |
| 1727 | |
| 1728 | void MToNumberInt32::computeRange(TempAllocator& alloc) { |
| 1729 | // No clamping since this computes the range *before* bailouts. |
| 1730 | setRange(new (alloc) Range(getOperand(0))); |
| 1731 | } |
| 1732 | |
| 1733 | void MBooleanToInt32::computeRange(TempAllocator& alloc) { |
| 1734 | setRange(Range::NewUInt32Range(alloc, 0, 1)); |
| 1735 | } |
| 1736 | |
| 1737 | void MLimitedTruncate::computeRange(TempAllocator& alloc) { |
| 1738 | Range* output = new (alloc) Range(input()); |
| 1739 | setRange(output); |
| 1740 | } |
| 1741 | |
| 1742 | static Range* GetArrayBufferViewRange(TempAllocator& alloc, Scalar::Type type) { |
| 1743 | switch (type) { |
| 1744 | case Scalar::Uint8Clamped: |
| 1745 | case Scalar::Uint8: |
| 1746 | return Range::NewUInt32Range(alloc, 0, UINT8_MAX(255)); |
| 1747 | case Scalar::Uint16: |
| 1748 | return Range::NewUInt32Range(alloc, 0, UINT16_MAX(65535)); |
| 1749 | case Scalar::Uint32: |
| 1750 | return Range::NewUInt32Range(alloc, 0, UINT32_MAX(4294967295U)); |
| 1751 | |
| 1752 | case Scalar::Int8: |
| 1753 | return Range::NewInt32Range(alloc, INT8_MIN(-128), INT8_MAX(127)); |
| 1754 | case Scalar::Int16: |
| 1755 | return Range::NewInt32Range(alloc, INT16_MIN(-32767-1), INT16_MAX(32767)); |
| 1756 | case Scalar::Int32: |
| 1757 | return Range::NewInt32Range(alloc, INT32_MIN(-2147483647-1), INT32_MAX(2147483647)); |
| 1758 | |
| 1759 | case Scalar::BigInt64: |
| 1760 | case Scalar::BigUint64: |
| 1761 | case Scalar::Int64: |
| 1762 | case Scalar::Simd128: |
| 1763 | case Scalar::Float16: |
| 1764 | case Scalar::Float32: |
| 1765 | case Scalar::Float64: |
| 1766 | case Scalar::MaxTypedArrayViewType: |
| 1767 | break; |
| 1768 | } |
| 1769 | return nullptr; |
| 1770 | } |
| 1771 | |
| 1772 | void MLoadUnboxedScalar::computeRange(TempAllocator& alloc) { |
| 1773 | // We have an Int32 type and if this is a UInt32 load it may produce a value |
| 1774 | // outside of our range, but we have a bailout to handle those cases. |
| 1775 | setRange(GetArrayBufferViewRange(alloc, storageType())); |
| 1776 | } |
| 1777 | |
| 1778 | void MLoadDataViewElement::computeRange(TempAllocator& alloc) { |
| 1779 | // We have an Int32 type and if this is a UInt32 load it may produce a value |
| 1780 | // outside of our range, but we have a bailout to handle those cases. |
| 1781 | setRange(GetArrayBufferViewRange(alloc, storageType())); |
| 1782 | } |
| 1783 | |
| 1784 | void MArrayLength::computeRange(TempAllocator& alloc) { |
| 1785 | // Array lengths can go up to UINT32_MAX. We will bail out if the array |
| 1786 | // length > INT32_MAX. |
| 1787 | MOZ_ASSERT(type() == MIRType::Int32)do { static_assert( mozilla::detail::AssertionConditionType< decltype(type() == MIRType::Int32)>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(type() == MIRType::Int32))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("type() == MIRType::Int32" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1787); AnnotateMozCrashReason("MOZ_ASSERT" "(" "type() == MIRType::Int32" ")"); do { *((volatile int*)__null) = 1787; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1788 | setRange(Range::NewUInt32Range(alloc, 0, INT32_MAX(2147483647))); |
| 1789 | } |
| 1790 | |
| 1791 | void MInitializedLength::computeRange(TempAllocator& alloc) { |
| 1792 | setRange( |
| 1793 | Range::NewUInt32Range(alloc, 0, NativeObject::MAX_DENSE_ELEMENTS_COUNT)); |
| 1794 | } |
| 1795 | |
| 1796 | void MArrayBufferViewLength::computeRange(TempAllocator& alloc) { |
| 1797 | if constexpr (ArrayBufferObject::ByteLengthLimit <= INT32_MAX(2147483647)) { |
| 1798 | setRange(Range::NewUInt32Range(alloc, 0, INT32_MAX(2147483647))); |
| 1799 | } |
| 1800 | } |
| 1801 | |
| 1802 | void MArrayBufferViewByteOffset::computeRange(TempAllocator& alloc) { |
| 1803 | if constexpr (ArrayBufferObject::ByteLengthLimit <= INT32_MAX(2147483647)) { |
| 1804 | setRange(Range::NewUInt32Range(alloc, 0, INT32_MAX(2147483647))); |
| 1805 | } |
| 1806 | } |
| 1807 | |
| 1808 | void MResizableTypedArrayByteOffsetMaybeOutOfBounds::computeRange( |
| 1809 | TempAllocator& alloc) { |
| 1810 | if constexpr (ArrayBufferObject::ByteLengthLimit <= INT32_MAX(2147483647)) { |
| 1811 | setRange(Range::NewUInt32Range(alloc, 0, INT32_MAX(2147483647))); |
| 1812 | } |
| 1813 | } |
| 1814 | |
| 1815 | void MResizableTypedArrayLength::computeRange(TempAllocator& alloc) { |
| 1816 | if constexpr (ArrayBufferObject::ByteLengthLimit <= INT32_MAX(2147483647)) { |
| 1817 | setRange(Range::NewUInt32Range(alloc, 0, INT32_MAX(2147483647))); |
| 1818 | } |
| 1819 | } |
| 1820 | |
| 1821 | void MResizableDataViewByteLength::computeRange(TempAllocator& alloc) { |
| 1822 | if constexpr (ArrayBufferObject::ByteLengthLimit <= INT32_MAX(2147483647)) { |
| 1823 | setRange(Range::NewUInt32Range(alloc, 0, INT32_MAX(2147483647))); |
| 1824 | } |
| 1825 | } |
| 1826 | |
| 1827 | void MTypedArrayElementSize::computeRange(TempAllocator& alloc) { |
| 1828 | constexpr auto MaxTypedArraySize = sizeof(double); |
| 1829 | |
| 1830 | #define ASSERT_MAX_SIZE(_, T, N) \ |
| 1831 | static_assert(sizeof(T) <= MaxTypedArraySize, \ |
| 1832 | "unexpected typed array type exceeding 64-bits storage"); |
| 1833 | JS_FOR_EACH_TYPED_ARRAY(ASSERT_MAX_SIZE)ASSERT_MAX_SIZE(int8_t, int8_t, Int8) ASSERT_MAX_SIZE(uint8_t , uint8_t, Uint8) ASSERT_MAX_SIZE(int16_t, int16_t, Int16) ASSERT_MAX_SIZE (uint16_t, uint16_t, Uint16) ASSERT_MAX_SIZE(int32_t, int32_t , Int32) ASSERT_MAX_SIZE(uint32_t, uint32_t, Uint32) ASSERT_MAX_SIZE (float, float, Float32) ASSERT_MAX_SIZE(double, double, Float64 ) ASSERT_MAX_SIZE(uint8_t, js::uint8_clamped, Uint8Clamped) ASSERT_MAX_SIZE (int64_t, int64_t, BigInt64) ASSERT_MAX_SIZE(uint64_t, uint64_t , BigUint64) ASSERT_MAX_SIZE(uint16_t, js::float16, Float16) |
| 1834 | #undef ASSERT_MAX_SIZE |
| 1835 | |
| 1836 | setRange(Range::NewUInt32Range(alloc, 0, MaxTypedArraySize)); |
| 1837 | } |
| 1838 | |
| 1839 | void MStringLength::computeRange(TempAllocator& alloc) { |
| 1840 | static_assert(JSString::MAX_LENGTH <= UINT32_MAX(4294967295U), |
| 1841 | "NewUInt32Range requires a uint32 value"); |
| 1842 | setRange(Range::NewUInt32Range(alloc, 0, JSString::MAX_LENGTH)); |
| 1843 | } |
| 1844 | |
| 1845 | void MArgumentsLength::computeRange(TempAllocator& alloc) { |
| 1846 | // This is is a conservative upper bound on what |TooManyActualArguments| |
| 1847 | // checks. If exceeded, Ion will not be entered in the first place. |
| 1848 | static_assert(ARGS_LENGTH_MAX <= UINT32_MAX(4294967295U), |
| 1849 | "NewUInt32Range requires a uint32 value"); |
| 1850 | setRange(Range::NewUInt32Range(alloc, 0, ARGS_LENGTH_MAX)); |
| 1851 | } |
| 1852 | |
| 1853 | void MBoundsCheck::computeRange(TempAllocator& alloc) { |
| 1854 | // Just transfer the incoming index range to the output. The length() is |
| 1855 | // also interesting, but it is handled as a bailout check, and we're |
| 1856 | // computing a pre-bailout range here. |
| 1857 | setRange(new (alloc) Range(index())); |
| 1858 | } |
| 1859 | |
| 1860 | void MSpectreMaskIndex::computeRange(TempAllocator& alloc) { |
| 1861 | // Just transfer the incoming index range to the output for now. |
| 1862 | setRange(new (alloc) Range(index())); |
| 1863 | } |
| 1864 | |
| 1865 | void MInt32ToIntPtr::computeRange(TempAllocator& alloc) { |
| 1866 | setRange(new (alloc) Range(input())); |
| 1867 | } |
| 1868 | |
| 1869 | void MNonNegativeIntPtrToInt32::computeRange(TempAllocator& alloc) { |
| 1870 | // We will bail out if the IntPtr value > INT32_MAX. |
| 1871 | setRange(Range::NewUInt32Range(alloc, 0, INT32_MAX(2147483647))); |
| 1872 | } |
| 1873 | |
| 1874 | void MArrayPush::computeRange(TempAllocator& alloc) { |
| 1875 | // MArrayPush returns the new array length. It bails out if the new length |
| 1876 | // doesn't fit in an Int32. |
| 1877 | MOZ_ASSERT(type() == MIRType::Int32)do { static_assert( mozilla::detail::AssertionConditionType< decltype(type() == MIRType::Int32)>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(type() == MIRType::Int32))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("type() == MIRType::Int32" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1877); AnnotateMozCrashReason("MOZ_ASSERT" "(" "type() == MIRType::Int32" ")"); do { *((volatile int*)__null) = 1877; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1878 | setRange(Range::NewUInt32Range(alloc, 0, INT32_MAX(2147483647))); |
| 1879 | } |
| 1880 | |
| 1881 | void MMathFunction::computeRange(TempAllocator& alloc) { |
| 1882 | Range opRange(getOperand(0)); |
| 1883 | switch (function()) { |
| 1884 | case UnaryMathFunction::SinNative: |
| 1885 | case UnaryMathFunction::SinFdlibm: |
| 1886 | case UnaryMathFunction::CosNative: |
| 1887 | case UnaryMathFunction::CosFdlibm: |
| 1888 | if (!opRange.canBeInfiniteOrNaN()) { |
| 1889 | setRange(Range::NewDoubleRange(alloc, -1.0, 1.0)); |
| 1890 | } |
| 1891 | break; |
| 1892 | default: |
| 1893 | break; |
| 1894 | } |
| 1895 | } |
| 1896 | |
| 1897 | void MSign::computeRange(TempAllocator& alloc) { |
| 1898 | Range opRange(getOperand(0)); |
| 1899 | setRange(Range::sign(alloc, &opRange)); |
| 1900 | } |
| 1901 | |
| 1902 | void MRandom::computeRange(TempAllocator& alloc) { |
| 1903 | Range* r = Range::NewDoubleRange(alloc, 0.0, 1.0); |
| 1904 | |
| 1905 | // Random never returns negative zero. |
| 1906 | r->refineToExcludeNegativeZero(); |
| 1907 | |
| 1908 | setRange(r); |
| 1909 | } |
| 1910 | |
| 1911 | void MNaNToZero::computeRange(TempAllocator& alloc) { |
| 1912 | Range other(input()); |
| 1913 | setRange(Range::NaNToZero(alloc, &other)); |
| 1914 | } |
| 1915 | |
| 1916 | /////////////////////////////////////////////////////////////////////////////// |
| 1917 | // Range Analysis |
| 1918 | /////////////////////////////////////////////////////////////////////////////// |
| 1919 | |
| 1920 | static BranchDirection NegateBranchDirection(BranchDirection dir) { |
| 1921 | return (dir == FALSE_BRANCH) ? TRUE_BRANCH : FALSE_BRANCH; |
| 1922 | } |
| 1923 | |
| 1924 | bool RangeAnalysis::analyzeLoop(MBasicBlock* header) { |
| 1925 | MOZ_ASSERT(header->hasUniqueBackedge())do { static_assert( mozilla::detail::AssertionConditionType< decltype(header->hasUniqueBackedge())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(header->hasUniqueBackedge ()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("header->hasUniqueBackedge()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 1925); AnnotateMozCrashReason("MOZ_ASSERT" "(" "header->hasUniqueBackedge()" ")"); do { *((volatile int*)__null) = 1925; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 1926 | |
| 1927 | // Try to compute an upper bound on the number of times the loop backedge |
| 1928 | // will be taken. Look for tests that dominate the backedge and which have |
| 1929 | // an edge leaving the loop body. |
| 1930 | MBasicBlock* backedge = header->backedge(); |
| 1931 | |
| 1932 | // Ignore trivial infinite loops. |
| 1933 | if (backedge == header) { |
| 1934 | return true; |
| 1935 | } |
| 1936 | |
| 1937 | bool canOsr; |
| 1938 | size_t numBlocks = MarkLoopBlocks(graph_, header, &canOsr); |
| 1939 | |
| 1940 | // Ignore broken loops. |
| 1941 | if (numBlocks == 0) { |
| 1942 | return true; |
| 1943 | } |
| 1944 | |
| 1945 | LoopIterationBound* iterationBound = nullptr; |
| 1946 | |
| 1947 | MBasicBlock* block = backedge; |
| 1948 | do { |
| 1949 | BranchDirection direction; |
| 1950 | MTest* branch = block->immediateDominatorBranch(&direction); |
| 1951 | |
| 1952 | if (block == block->immediateDominator()) { |
| 1953 | break; |
| 1954 | } |
| 1955 | |
| 1956 | block = block->immediateDominator(); |
| 1957 | |
| 1958 | if (branch) { |
| 1959 | direction = NegateBranchDirection(direction); |
| 1960 | MBasicBlock* otherBlock = branch->branchSuccessor(direction); |
| 1961 | if (!otherBlock->isMarked()) { |
| 1962 | if (!alloc().ensureBallast()) { |
| 1963 | return false; |
| 1964 | } |
| 1965 | iterationBound = analyzeLoopIterationCount(header, branch, direction); |
| 1966 | if (iterationBound) { |
| 1967 | break; |
| 1968 | } |
| 1969 | } |
| 1970 | } |
| 1971 | } while (block != header); |
| 1972 | |
| 1973 | if (!iterationBound) { |
| 1974 | UnmarkLoopBlocks(graph_, header); |
| 1975 | return true; |
| 1976 | } |
| 1977 | |
| 1978 | if (!loopIterationBounds.append(iterationBound)) { |
| 1979 | return false; |
| 1980 | } |
| 1981 | |
| 1982 | #ifdef DEBUG1 |
| 1983 | if (JitSpewEnabled(JitSpew_Range)) { |
| 1984 | Sprinter sp(GetJitContext()->cx); |
| 1985 | if (!sp.init()) { |
| 1986 | return false; |
| 1987 | } |
| 1988 | iterationBound->boundSum.dump(sp); |
| 1989 | JS::UniqueChars str = sp.release(); |
| 1990 | if (!str) { |
| 1991 | return false; |
| 1992 | } |
| 1993 | JitSpew(JitSpew_Range, "computed symbolic bound on backedges: %s", |
| 1994 | str.get()); |
| 1995 | } |
| 1996 | #endif |
| 1997 | |
| 1998 | // Try to compute symbolic bounds for the phi nodes at the head of this |
| 1999 | // loop, expressed in terms of the iteration bound just computed. |
| 2000 | |
| 2001 | for (MPhiIterator iter(header->phisBegin()); iter != header->phisEnd(); |
| 2002 | iter++) { |
| 2003 | analyzeLoopPhi(iterationBound, *iter); |
| 2004 | } |
| 2005 | |
| 2006 | if (!mir->compilingWasm() && !mir->outerInfo().hadBoundsCheckBailout()) { |
| 2007 | // Try to hoist any bounds checks from the loop using symbolic bounds. |
| 2008 | |
| 2009 | Vector<MBoundsCheck*, 0, JitAllocPolicy> hoistedChecks(alloc()); |
| 2010 | |
| 2011 | for (ReversePostorderIterator iter(graph_.rpoBegin(header)); |
| 2012 | iter != graph_.rpoEnd(); iter++) { |
| 2013 | MBasicBlock* block = *iter; |
| 2014 | if (!block->isMarked()) { |
| 2015 | continue; |
| 2016 | } |
| 2017 | |
| 2018 | for (MDefinitionIterator iter(block); iter; iter++) { |
| 2019 | MDefinition* def = *iter; |
| 2020 | if (def->isBoundsCheck() && def->isMovable()) { |
| 2021 | if (!alloc().ensureBallast()) { |
| 2022 | return false; |
| 2023 | } |
| 2024 | if (tryHoistBoundsCheck(header, def->toBoundsCheck())) { |
| 2025 | if (!hoistedChecks.append(def->toBoundsCheck())) { |
| 2026 | return false; |
| 2027 | } |
| 2028 | } |
| 2029 | } |
| 2030 | } |
| 2031 | } |
| 2032 | |
| 2033 | // Note: replace all uses of the original bounds check with the |
| 2034 | // actual index. This is usually done during bounds check elimination, |
| 2035 | // but in this case it's safe to do it here since the load/store is |
| 2036 | // definitely not loop-invariant, so we will never move it before |
| 2037 | // one of the bounds checks we just added. |
| 2038 | for (size_t i = 0; i < hoistedChecks.length(); i++) { |
| 2039 | MBoundsCheck* ins = hoistedChecks[i]; |
| 2040 | ins->replaceAllUsesWith(ins->index()); |
| 2041 | ins->block()->discard(ins); |
| 2042 | } |
| 2043 | } |
| 2044 | |
| 2045 | UnmarkLoopBlocks(graph_, header); |
| 2046 | return true; |
| 2047 | } |
| 2048 | |
| 2049 | // Unbox beta nodes in order to hoist instruction properly, and not be limited |
| 2050 | // by the beta nodes which are added after each branch. |
| 2051 | static inline MDefinition* DefinitionOrBetaInputDefinition(MDefinition* ins) { |
| 2052 | while (ins->isBeta()) { |
| 2053 | ins = ins->toBeta()->input(); |
| 2054 | } |
| 2055 | return ins; |
| 2056 | } |
| 2057 | |
| 2058 | LoopIterationBound* RangeAnalysis::analyzeLoopIterationCount( |
| 2059 | MBasicBlock* header, MTest* test, BranchDirection direction) { |
| 2060 | SimpleLinearSum lhs(nullptr, 0); |
| 2061 | MDefinition* rhs; |
| 2062 | bool lessEqual; |
| 2063 | if (!ExtractLinearInequality(test, direction, &lhs, &rhs, &lessEqual)) { |
| 2064 | return nullptr; |
| 2065 | } |
| 2066 | |
| 2067 | // Ensure the rhs is a loop invariant term. |
| 2068 | if (rhs && rhs->block()->isMarked()) { |
| 2069 | if (lhs.term && lhs.term->block()->isMarked()) { |
| 2070 | return nullptr; |
| 2071 | } |
| 2072 | MDefinition* temp = lhs.term; |
| 2073 | lhs.term = rhs; |
| 2074 | rhs = temp; |
| 2075 | if (!SafeSub(0, lhs.constant, &lhs.constant)) { |
| 2076 | return nullptr; |
| 2077 | } |
| 2078 | lessEqual = !lessEqual; |
| 2079 | } |
| 2080 | |
| 2081 | MOZ_ASSERT_IF(rhs, !rhs->block()->isMarked())do { if (rhs) { do { static_assert( mozilla::detail::AssertionConditionType <decltype(!rhs->block()->isMarked())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(!rhs->block()->isMarked ()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("!rhs->block()->isMarked()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2081); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!rhs->block()->isMarked()" ")"); do { *((volatile int*)__null) = 2081; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); } } while ( false); |
| 2082 | |
| 2083 | // Ensure the lhs is a phi node from the start of the loop body. |
| 2084 | if (!lhs.term || !lhs.term->isPhi() || lhs.term->block() != header) { |
| 2085 | return nullptr; |
| 2086 | } |
| 2087 | |
| 2088 | // Check that the value of the lhs changes by a constant amount with each |
| 2089 | // loop iteration. This requires that the lhs be written in every loop |
| 2090 | // iteration with a value that is a constant difference from its value at |
| 2091 | // the start of the iteration. |
| 2092 | |
| 2093 | if (lhs.term->toPhi()->numOperands() != 2) { |
| 2094 | return nullptr; |
| 2095 | } |
| 2096 | |
| 2097 | // The first operand of the phi should be the lhs' value at the start of |
| 2098 | // the first executed iteration, and not a value written which could |
| 2099 | // replace the second operand below during the middle of execution. |
| 2100 | MDefinition* lhsInitial = lhs.term->toPhi()->getLoopPredecessorOperand(); |
| 2101 | if (lhsInitial->block()->isMarked()) { |
| 2102 | return nullptr; |
| 2103 | } |
| 2104 | |
| 2105 | // The second operand of the phi should be a value written by an add/sub |
| 2106 | // in every loop iteration, i.e. in a block which dominates the backedge. |
| 2107 | MDefinition* lhsWrite = DefinitionOrBetaInputDefinition( |
| 2108 | lhs.term->toPhi()->getLoopBackedgeOperand()); |
| 2109 | if (!lhsWrite->isAdd() && !lhsWrite->isSub()) { |
| 2110 | return nullptr; |
| 2111 | } |
| 2112 | if (!lhsWrite->block()->isMarked()) { |
| 2113 | return nullptr; |
| 2114 | } |
| 2115 | MBasicBlock* bb = header->backedge(); |
| 2116 | for (; bb != lhsWrite->block() && bb != header; |
| 2117 | bb = bb->immediateDominator()) { |
| 2118 | } |
| 2119 | if (bb != lhsWrite->block()) { |
| 2120 | return nullptr; |
| 2121 | } |
| 2122 | |
| 2123 | SimpleLinearSum lhsModified = ExtractLinearSum(lhsWrite); |
| 2124 | |
| 2125 | // Check that the value of the lhs at the backedge is of the form |
| 2126 | // 'old(lhs) + N'. We can be sure that old(lhs) is the value at the start |
| 2127 | // of the iteration, and not that written to lhs in a previous iteration, |
| 2128 | // as such a previous value could not appear directly in the addition: |
| 2129 | // it could not be stored in lhs as the lhs add/sub executes in every |
| 2130 | // iteration, and if it were stored in another variable its use here would |
| 2131 | // be as an operand to a phi node for that variable. |
| 2132 | if (lhsModified.term != lhs.term) { |
| 2133 | return nullptr; |
| 2134 | } |
| 2135 | |
| 2136 | LinearSum iterationBound(alloc()); |
| 2137 | LinearSum currentIteration(alloc()); |
| 2138 | |
| 2139 | if (lhsModified.constant == 1 && !lessEqual) { |
| 2140 | // The value of lhs is 'initial(lhs) + iterCount' and this will end |
| 2141 | // execution of the loop if 'lhs + lhsN >= rhs'. Thus, an upper bound |
| 2142 | // on the number of backedges executed is: |
| 2143 | // |
| 2144 | // initial(lhs) + iterCount + lhsN == rhs |
| 2145 | // iterCount == rhsN - initial(lhs) - lhsN |
| 2146 | |
| 2147 | if (rhs) { |
| 2148 | if (!iterationBound.add(rhs, 1)) { |
| 2149 | return nullptr; |
| 2150 | } |
| 2151 | } |
| 2152 | if (!iterationBound.add(lhsInitial, -1)) { |
| 2153 | return nullptr; |
| 2154 | } |
| 2155 | |
| 2156 | int32_t lhsConstant; |
| 2157 | if (!SafeSub(0, lhs.constant, &lhsConstant)) { |
| 2158 | return nullptr; |
| 2159 | } |
| 2160 | if (!iterationBound.add(lhsConstant)) { |
| 2161 | return nullptr; |
| 2162 | } |
| 2163 | |
| 2164 | if (!currentIteration.add(lhs.term, 1)) { |
| 2165 | return nullptr; |
| 2166 | } |
| 2167 | if (!currentIteration.add(lhsInitial, -1)) { |
| 2168 | return nullptr; |
| 2169 | } |
| 2170 | } else if (lhsModified.constant == -1 && lessEqual) { |
| 2171 | // The value of lhs is 'initial(lhs) - iterCount'. Similar to the above |
| 2172 | // case, an upper bound on the number of backedges executed is: |
| 2173 | // |
| 2174 | // initial(lhs) - iterCount + lhsN == rhs |
| 2175 | // iterCount == initial(lhs) - rhs + lhsN |
| 2176 | |
| 2177 | if (!iterationBound.add(lhsInitial, 1)) { |
| 2178 | return nullptr; |
| 2179 | } |
| 2180 | if (rhs) { |
| 2181 | if (!iterationBound.add(rhs, -1)) { |
| 2182 | return nullptr; |
| 2183 | } |
| 2184 | } |
| 2185 | if (!iterationBound.add(lhs.constant)) { |
| 2186 | return nullptr; |
| 2187 | } |
| 2188 | |
| 2189 | if (!currentIteration.add(lhsInitial, 1)) { |
| 2190 | return nullptr; |
| 2191 | } |
| 2192 | if (!currentIteration.add(lhs.term, -1)) { |
| 2193 | return nullptr; |
| 2194 | } |
| 2195 | } else { |
| 2196 | return nullptr; |
| 2197 | } |
| 2198 | |
| 2199 | return new (alloc()) |
| 2200 | LoopIterationBound(header, test, iterationBound, currentIteration); |
| 2201 | } |
| 2202 | |
| 2203 | void RangeAnalysis::analyzeLoopPhi(LoopIterationBound* loopBound, MPhi* phi) { |
| 2204 | // Given a bound on the number of backedges taken, compute an upper and |
| 2205 | // lower bound for a phi node that may change by a constant amount each |
| 2206 | // iteration. Unlike for the case when computing the iteration bound |
| 2207 | // itself, the phi does not need to change the same amount every iteration, |
| 2208 | // but is required to change at most N and be either nondecreasing or |
| 2209 | // nonincreasing. |
| 2210 | |
| 2211 | MOZ_ASSERT(phi->numOperands() == 2)do { static_assert( mozilla::detail::AssertionConditionType< decltype(phi->numOperands() == 2)>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(phi->numOperands() == 2)) ), 0))) { do { } while (false); MOZ_ReportAssertionFailure("phi->numOperands() == 2" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2211); AnnotateMozCrashReason("MOZ_ASSERT" "(" "phi->numOperands() == 2" ")"); do { *((volatile int*)__null) = 2211; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2212 | |
| 2213 | MDefinition* initial = phi->getLoopPredecessorOperand(); |
| 2214 | if (initial->block()->isMarked()) { |
| 2215 | return; |
| 2216 | } |
| 2217 | |
| 2218 | SimpleLinearSum modified = |
| 2219 | ExtractLinearSum(phi->getLoopBackedgeOperand(), MathSpace::Infinite); |
| 2220 | |
| 2221 | if (modified.term != phi || modified.constant == 0) { |
| 2222 | return; |
| 2223 | } |
| 2224 | |
| 2225 | if (!phi->range()) { |
| 2226 | phi->setRange(new (alloc()) Range(phi)); |
| 2227 | } |
| 2228 | |
| 2229 | LinearSum initialSum(alloc()); |
| 2230 | if (!initialSum.add(initial, 1)) { |
| 2231 | return; |
| 2232 | } |
| 2233 | |
| 2234 | // The phi may change by N each iteration, and is either nondecreasing or |
| 2235 | // nonincreasing. initial(phi) is either a lower or upper bound for the |
| 2236 | // phi, and initial(phi) + loopBound * N is either an upper or lower bound, |
| 2237 | // at all points within the loop, provided that loopBound >= 0. |
| 2238 | // |
| 2239 | // We are more interested, however, in the bound for phi at points |
| 2240 | // dominated by the loop bound's test; if the test dominates e.g. a bounds |
| 2241 | // check we want to hoist from the loop, using the value of the phi at the |
| 2242 | // head of the loop for this will usually be too imprecise to hoist the |
| 2243 | // check. These points will execute only if the backedge executes at least |
| 2244 | // one more time (as the test passed and the test dominates the backedge), |
| 2245 | // so we know both that loopBound >= 1 and that the phi's value has changed |
| 2246 | // at most loopBound - 1 times. Thus, another upper or lower bound for the |
| 2247 | // phi is initial(phi) + (loopBound - 1) * N, without requiring us to |
| 2248 | // ensure that loopBound >= 0. |
| 2249 | |
| 2250 | LinearSum limitSum(loopBound->boundSum); |
| 2251 | if (!limitSum.multiply(modified.constant) || !limitSum.add(initialSum)) { |
| 2252 | return; |
| 2253 | } |
| 2254 | |
| 2255 | int32_t negativeConstant; |
| 2256 | if (!SafeSub(0, modified.constant, &negativeConstant) || |
| 2257 | !limitSum.add(negativeConstant)) { |
| 2258 | return; |
| 2259 | } |
| 2260 | |
| 2261 | Range* initRange = initial->range(); |
| 2262 | if (modified.constant > 0) { |
| 2263 | if (initRange && initRange->hasInt32LowerBound()) { |
| 2264 | phi->range()->refineLower(initRange->lower()); |
| 2265 | } |
| 2266 | phi->range()->setSymbolicLower( |
| 2267 | SymbolicBound::New(alloc(), nullptr, initialSum)); |
| 2268 | phi->range()->setSymbolicUpper( |
| 2269 | SymbolicBound::New(alloc(), loopBound, limitSum)); |
| 2270 | } else { |
| 2271 | if (initRange && initRange->hasInt32UpperBound()) { |
| 2272 | phi->range()->refineUpper(initRange->upper()); |
| 2273 | } |
| 2274 | phi->range()->setSymbolicUpper( |
| 2275 | SymbolicBound::New(alloc(), nullptr, initialSum)); |
| 2276 | phi->range()->setSymbolicLower( |
| 2277 | SymbolicBound::New(alloc(), loopBound, limitSum)); |
| 2278 | } |
| 2279 | |
| 2280 | JitSpew(JitSpew_Range, "added symbolic range on %u", phi->id()); |
| 2281 | SpewRange(phi); |
| 2282 | } |
| 2283 | |
| 2284 | // Whether bound is valid at the specified bounds check instruction in a loop, |
| 2285 | // and may be used to hoist ins. |
| 2286 | static inline bool SymbolicBoundIsValid(MBasicBlock* header, MBoundsCheck* ins, |
| 2287 | const SymbolicBound* bound) { |
| 2288 | if (!bound->loop) { |
| 2289 | return true; |
| 2290 | } |
| 2291 | if (ins->block() == header) { |
| 2292 | return false; |
| 2293 | } |
| 2294 | MBasicBlock* bb = ins->block()->immediateDominator(); |
| 2295 | while (bb != header && bb != bound->loop->test->block()) { |
| 2296 | bb = bb->immediateDominator(); |
| 2297 | } |
| 2298 | return bb == bound->loop->test->block(); |
| 2299 | } |
| 2300 | |
| 2301 | bool RangeAnalysis::tryHoistBoundsCheck(MBasicBlock* header, |
| 2302 | MBoundsCheck* ins) { |
| 2303 | // The bounds check's length must be loop invariant or a constant. |
| 2304 | MDefinition* length = DefinitionOrBetaInputDefinition(ins->length()); |
| 2305 | if (length->block()->isMarked() && !length->isConstant()) { |
| 2306 | return false; |
| 2307 | } |
| 2308 | |
| 2309 | // The bounds check's index should not be loop invariant (else we would |
| 2310 | // already have hoisted it during LICM). |
| 2311 | SimpleLinearSum index = ExtractLinearSum(ins->index()); |
| 2312 | if (!index.term || !index.term->block()->isMarked()) { |
| 2313 | return false; |
| 2314 | } |
| 2315 | |
| 2316 | // Check for a symbolic lower and upper bound on the index. If either |
| 2317 | // condition depends on an iteration bound for the loop, only hoist if |
| 2318 | // the bounds check is dominated by the iteration bound's test. |
| 2319 | if (!index.term->range()) { |
| 2320 | return false; |
| 2321 | } |
| 2322 | const SymbolicBound* lower = index.term->range()->symbolicLower(); |
| 2323 | if (!lower || !SymbolicBoundIsValid(header, ins, lower)) { |
| 2324 | return false; |
| 2325 | } |
| 2326 | const SymbolicBound* upper = index.term->range()->symbolicUpper(); |
| 2327 | if (!upper || !SymbolicBoundIsValid(header, ins, upper)) { |
| 2328 | return false; |
| 2329 | } |
| 2330 | |
| 2331 | MBasicBlock* preLoop = header->loopPredecessor(); |
| 2332 | MOZ_ASSERT(!preLoop->isMarked())do { static_assert( mozilla::detail::AssertionConditionType< decltype(!preLoop->isMarked())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(!preLoop->isMarked()))), 0 ))) { do { } while (false); MOZ_ReportAssertionFailure("!preLoop->isMarked()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2332); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!preLoop->isMarked()" ")"); do { *((volatile int*)__null) = 2332; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2333 | |
| 2334 | MDefinition* lowerTerm = ConvertLinearSum(alloc(), preLoop, lower->sum, |
| 2335 | BailoutKind::HoistBoundsCheck); |
| 2336 | if (!lowerTerm) { |
| 2337 | return false; |
| 2338 | } |
| 2339 | |
| 2340 | MDefinition* upperTerm = ConvertLinearSum(alloc(), preLoop, upper->sum, |
| 2341 | BailoutKind::HoistBoundsCheck); |
| 2342 | if (!upperTerm) { |
| 2343 | return false; |
| 2344 | } |
| 2345 | |
| 2346 | // We are checking that index + indexConstant >= 0, and know that |
| 2347 | // index >= lowerTerm + lowerConstant. Thus, check that: |
| 2348 | // |
| 2349 | // lowerTerm + lowerConstant + indexConstant >= 0 |
| 2350 | // lowerTerm >= -lowerConstant - indexConstant |
| 2351 | |
| 2352 | int32_t lowerConstant = 0; |
| 2353 | if (!SafeSub(lowerConstant, index.constant, &lowerConstant)) { |
| 2354 | return false; |
| 2355 | } |
| 2356 | if (!SafeSub(lowerConstant, lower->sum.constant(), &lowerConstant)) { |
| 2357 | return false; |
| 2358 | } |
| 2359 | |
| 2360 | // We are checking that index < boundsLength, and know that |
| 2361 | // index <= upperTerm + upperConstant. Thus, check that: |
| 2362 | // |
| 2363 | // upperTerm + upperConstant < boundsLength |
| 2364 | |
| 2365 | int32_t upperConstant = index.constant; |
| 2366 | if (!SafeAdd(upper->sum.constant(), upperConstant, &upperConstant)) { |
| 2367 | return false; |
| 2368 | } |
| 2369 | |
| 2370 | // Hoist the loop invariant lower bounds checks. |
| 2371 | MBoundsCheckLower* lowerCheck = MBoundsCheckLower::New(alloc(), lowerTerm); |
| 2372 | lowerCheck->setMinimum(lowerConstant); |
| 2373 | lowerCheck->computeRange(alloc()); |
| 2374 | lowerCheck->collectRangeInfoPreTrunc(); |
| 2375 | lowerCheck->setBailoutKind(BailoutKind::HoistBoundsCheck); |
| 2376 | preLoop->insertBefore(preLoop->lastIns(), lowerCheck); |
| 2377 | |
| 2378 | // A common pattern for iterating over typed arrays is this: |
| 2379 | // |
| 2380 | // for (var i = 0; i < ta.length; i++) { |
| 2381 | // use ta[i]; |
| 2382 | // } |
| 2383 | // |
| 2384 | // Here |upperTerm| (= ta.length) is a NonNegativeIntPtrToInt32 instruction. |
| 2385 | // Unwrap this if |length| is also an IntPtr so that we don't add an |
| 2386 | // unnecessary bounds check and Int32ToIntPtr below. |
| 2387 | if (upperTerm->isNonNegativeIntPtrToInt32() && |
| 2388 | length->type() == MIRType::IntPtr) { |
| 2389 | upperTerm = upperTerm->toNonNegativeIntPtrToInt32()->input(); |
| 2390 | } |
| 2391 | |
| 2392 | // Hoist the loop invariant upper bounds checks. |
| 2393 | if (upperTerm != length || upperConstant >= 0) { |
| 2394 | // Hoist the bound check's length if it isn't already loop invariant. |
| 2395 | if (length->block()->isMarked()) { |
| 2396 | MOZ_ASSERT(length->isConstant())do { static_assert( mozilla::detail::AssertionConditionType< decltype(length->isConstant())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(length->isConstant()))), 0 ))) { do { } while (false); MOZ_ReportAssertionFailure("length->isConstant()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2396); AnnotateMozCrashReason("MOZ_ASSERT" "(" "length->isConstant()" ")"); do { *((volatile int*)__null) = 2396; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2397 | MInstruction* lengthIns = length->toInstruction(); |
| 2398 | lengthIns->block()->moveBefore(preLoop->lastIns(), lengthIns); |
| 2399 | } |
| 2400 | |
| 2401 | // If the length is IntPtr, convert the upperTerm to that as well for the |
| 2402 | // bounds check. |
| 2403 | if (length->type() == MIRType::IntPtr && |
| 2404 | upperTerm->type() == MIRType::Int32) { |
| 2405 | upperTerm = MInt32ToIntPtr::New(alloc(), upperTerm); |
| 2406 | upperTerm->computeRange(alloc()); |
| 2407 | upperTerm->collectRangeInfoPreTrunc(); |
| 2408 | preLoop->insertBefore(preLoop->lastIns(), upperTerm->toInstruction()); |
| 2409 | } |
| 2410 | |
| 2411 | MBoundsCheck* upperCheck = MBoundsCheck::New(alloc(), upperTerm, length); |
| 2412 | upperCheck->setMinimum(upperConstant); |
| 2413 | upperCheck->setMaximum(upperConstant); |
| 2414 | upperCheck->computeRange(alloc()); |
| 2415 | upperCheck->collectRangeInfoPreTrunc(); |
| 2416 | upperCheck->setBailoutKind(BailoutKind::HoistBoundsCheck); |
| 2417 | preLoop->insertBefore(preLoop->lastIns(), upperCheck); |
| 2418 | } |
| 2419 | |
| 2420 | return true; |
| 2421 | } |
| 2422 | |
| 2423 | bool RangeAnalysis::analyze() { |
| 2424 | JitSpew(JitSpew_Range, "Doing range propagation"); |
| 2425 | |
| 2426 | for (ReversePostorderIterator iter(graph_.rpoBegin()); |
| 2427 | iter != graph_.rpoEnd(); iter++) { |
| 2428 | MBasicBlock* block = *iter; |
| 2429 | // No blocks are supposed to be unreachable, except when we have an OSR |
| 2430 | // block, in which case the Value Numbering phase add fixup blocks which |
| 2431 | // are unreachable. |
| 2432 | MOZ_ASSERT(!block->unreachable() || graph_.osrBlock())do { static_assert( mozilla::detail::AssertionConditionType< decltype(!block->unreachable() || graph_.osrBlock())>:: isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(!block->unreachable() || graph_.osrBlock()))), 0) )) { do { } while (false); MOZ_ReportAssertionFailure("!block->unreachable() || graph_.osrBlock()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2432); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!block->unreachable() || graph_.osrBlock()" ")"); do { *((volatile int*)__null) = 2432; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2433 | |
| 2434 | // If the block's immediate dominator is unreachable, the block is |
| 2435 | // unreachable. Iterating in RPO, we'll always see the immediate |
| 2436 | // dominator before the block. |
| 2437 | if (block->immediateDominator()->unreachable()) { |
| 2438 | block->setUnreachableUnchecked(); |
| 2439 | continue; |
| 2440 | } |
| 2441 | |
| 2442 | for (MDefinitionIterator iter(block); iter; iter++) { |
| 2443 | MDefinition* def = *iter; |
| 2444 | if (!alloc().ensureBallast()) { |
| 2445 | return false; |
| 2446 | } |
| 2447 | |
| 2448 | def->computeRange(alloc()); |
| 2449 | JitSpew(JitSpew_Range, "computing range on %u", def->id()); |
| 2450 | SpewRange(def); |
| 2451 | } |
| 2452 | |
| 2453 | // Beta node range analysis may have marked this block unreachable. If |
| 2454 | // so, it's no longer interesting to continue processing it. |
| 2455 | if (block->unreachable()) { |
| 2456 | continue; |
| 2457 | } |
| 2458 | |
| 2459 | if (block->isLoopHeader()) { |
| 2460 | if (!analyzeLoop(block)) { |
| 2461 | return false; |
| 2462 | } |
| 2463 | } |
| 2464 | |
| 2465 | // First pass at collecting range info - while the beta nodes are still |
| 2466 | // around and before truncation. |
| 2467 | for (MInstructionIterator iter(block->begin()); iter != block->end(); |
| 2468 | iter++) { |
| 2469 | iter->collectRangeInfoPreTrunc(); |
| 2470 | } |
| 2471 | } |
| 2472 | |
| 2473 | return true; |
| 2474 | } |
| 2475 | |
| 2476 | bool RangeAnalysis::addRangeAssertions() { |
| 2477 | if (!JitOptions.checkRangeAnalysis) { |
| 2478 | return true; |
| 2479 | } |
| 2480 | |
| 2481 | // Check the computed range for this instruction, if the option is set. Note |
| 2482 | // that this code is quite invasive; it adds numerous additional |
| 2483 | // instructions for each MInstruction with a computed range, and it uses |
| 2484 | // registers, so it also affects register allocation. |
| 2485 | for (ReversePostorderIterator iter(graph_.rpoBegin()); |
| 2486 | iter != graph_.rpoEnd(); iter++) { |
| 2487 | MBasicBlock* block = *iter; |
| 2488 | |
| 2489 | // Do not add assertions in unreachable blocks. |
| 2490 | if (block->unreachable()) { |
| 2491 | continue; |
| 2492 | } |
| 2493 | |
| 2494 | for (MDefinitionIterator iter(block); iter; iter++) { |
| 2495 | MDefinition* ins = *iter; |
| 2496 | |
| 2497 | // Perform range checking for all numeric and numeric-like types. |
| 2498 | if (!IsNumberType(ins->type()) && ins->type() != MIRType::Boolean && |
| 2499 | ins->type() != MIRType::Value && ins->type() != MIRType::IntPtr) { |
| 2500 | continue; |
| 2501 | } |
| 2502 | |
| 2503 | // MIsNoIter is fused with the MTest that follows it and emitted as |
| 2504 | // LIsNoIterAndBranch. Similarly, MIteratorHasIndices is fused to |
| 2505 | // become LIteratorHasIndicesAndBranch. Skip them to avoid complicating |
| 2506 | // lowering. |
| 2507 | if (ins->isIsNoIter() || ins->isIteratorHasIndices()) { |
| 2508 | MOZ_ASSERT(ins->hasOneUse())do { static_assert( mozilla::detail::AssertionConditionType< decltype(ins->hasOneUse())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(ins->hasOneUse()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("ins->hasOneUse()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2508); AnnotateMozCrashReason("MOZ_ASSERT" "(" "ins->hasOneUse()" ")"); do { *((volatile int*)__null) = 2508; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2509 | continue; |
| 2510 | } |
| 2511 | |
| 2512 | Range r(ins); |
| 2513 | |
| 2514 | MOZ_ASSERT_IF(ins->type() == MIRType::Int64, r.isUnknown())do { if (ins->type() == MIRType::Int64) { do { static_assert ( mozilla::detail::AssertionConditionType<decltype(r.isUnknown ())>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(r.isUnknown()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("r.isUnknown()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2514); AnnotateMozCrashReason("MOZ_ASSERT" "(" "r.isUnknown()" ")"); do { *((volatile int*)__null) = 2514; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); } } while ( false); |
| 2515 | |
| 2516 | // Don't insert assertions if there's nothing interesting to assert. |
| 2517 | if (r.isUnknown() || |
| 2518 | (ins->type() == MIRType::Int32 && r.isUnknownInt32())) { |
| 2519 | continue; |
| 2520 | } |
| 2521 | |
| 2522 | // Don't add a use to an instruction that is recovered on bailout. |
| 2523 | if (ins->isRecoveredOnBailout()) { |
| 2524 | continue; |
| 2525 | } |
| 2526 | |
| 2527 | if (!alloc().ensureBallast()) { |
| 2528 | return false; |
| 2529 | } |
| 2530 | MAssertRange* guard = |
| 2531 | MAssertRange::New(alloc(), ins, new (alloc()) Range(r)); |
| 2532 | |
| 2533 | // Beta nodes and interrupt checks are required to be located at the |
| 2534 | // beginnings of basic blocks, so we must insert range assertions |
| 2535 | // after any such instructions. |
| 2536 | MInstruction* insertAt = nullptr; |
| 2537 | if (block->graph().osrBlock() == block) { |
| 2538 | insertAt = ins->toInstruction(); |
| 2539 | } else { |
| 2540 | insertAt = block->safeInsertTop(ins); |
| 2541 | } |
| 2542 | |
| 2543 | if (insertAt == *iter) { |
| 2544 | block->insertAfter(insertAt, guard); |
| 2545 | } else { |
| 2546 | block->insertBefore(insertAt, guard); |
| 2547 | } |
| 2548 | } |
| 2549 | } |
| 2550 | |
| 2551 | return true; |
| 2552 | } |
| 2553 | |
| 2554 | /////////////////////////////////////////////////////////////////////////////// |
| 2555 | // Range based Truncation |
| 2556 | /////////////////////////////////////////////////////////////////////////////// |
| 2557 | |
| 2558 | void Range::clampToInt32() { |
| 2559 | if (isInt32()) { |
| 2560 | return; |
| 2561 | } |
| 2562 | int32_t l = hasInt32LowerBound() ? lower() : JSVAL_INT_MIN((int32_t)0x80000000); |
| 2563 | int32_t h = hasInt32UpperBound() ? upper() : JSVAL_INT_MAX((int32_t)0x7fffffff); |
| 2564 | setInt32(l, h); |
| 2565 | } |
| 2566 | |
| 2567 | void Range::wrapAroundToInt32() { |
| 2568 | if (!hasInt32Bounds()) { |
| 2569 | setInt32(JSVAL_INT_MIN((int32_t)0x80000000), JSVAL_INT_MAX((int32_t)0x7fffffff)); |
| 2570 | } else if (canHaveFractionalPart()) { |
| 2571 | // Clearing the fractional field may provide an opportunity to refine |
| 2572 | // lower_ or upper_. |
| 2573 | canHaveFractionalPart_ = ExcludesFractionalParts; |
| 2574 | canBeNegativeZero_ = ExcludesNegativeZero; |
| 2575 | refineInt32BoundsByExponent(max_exponent_, &lower_, &hasInt32LowerBound_, |
| 2576 | &upper_, &hasInt32UpperBound_); |
| 2577 | |
| 2578 | assertInvariants(); |
| 2579 | } else { |
| 2580 | // If nothing else, we can clear the negative zero flag. |
| 2581 | canBeNegativeZero_ = ExcludesNegativeZero; |
| 2582 | } |
| 2583 | MOZ_ASSERT(isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("isInt32()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2583); AnnotateMozCrashReason("MOZ_ASSERT" "(" "isInt32()" ")" ); do { *((volatile int*)__null) = 2583; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2584 | } |
| 2585 | |
| 2586 | void Range::wrapAroundToShiftCount() { |
| 2587 | wrapAroundToInt32(); |
| 2588 | if (lower() < 0 || upper() >= 32) { |
| 2589 | setInt32(0, 31); |
| 2590 | } |
| 2591 | } |
| 2592 | |
| 2593 | void Range::wrapAroundToBoolean() { |
| 2594 | wrapAroundToInt32(); |
| 2595 | if (!isBoolean()) { |
| 2596 | setInt32(0, 1); |
| 2597 | } |
| 2598 | MOZ_ASSERT(isBoolean())do { static_assert( mozilla::detail::AssertionConditionType< decltype(isBoolean())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(isBoolean()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("isBoolean()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2598); AnnotateMozCrashReason("MOZ_ASSERT" "(" "isBoolean()" ")"); do { *((volatile int*)__null) = 2598; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2599 | } |
| 2600 | |
| 2601 | bool MDefinition::canTruncate() const { |
| 2602 | // No procedure defined for truncating this instruction. |
| 2603 | return false; |
| 2604 | } |
| 2605 | |
| 2606 | void MDefinition::truncate(TruncateKind kind) { |
| 2607 | MOZ_CRASH("No procedure defined for truncating this instruction.")do { do { } while (false); MOZ_ReportCrash("" "No procedure defined for truncating this instruction." , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2607); AnnotateMozCrashReason("MOZ_CRASH(" "No procedure defined for truncating this instruction." ")"); do { *((volatile int*)__null) = 2607; __attribute__((nomerge )) ::abort(); } while (false); } while (false); |
| 2608 | } |
| 2609 | |
| 2610 | bool MConstant::canTruncate() const { return IsFloatingPointType(type()); } |
| 2611 | |
| 2612 | void MConstant::truncate(TruncateKind kind) { |
| 2613 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2613); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2613; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2614 | |
| 2615 | // Truncate the double to int, since all uses truncates it. |
| 2616 | int32_t res = ToInt32(numberToDouble()); |
| 2617 | payload_.asBits = 0; |
| 2618 | payload_.i32 = res; |
| 2619 | setResultType(MIRType::Int32); |
| 2620 | if (range()) { |
| 2621 | range()->setInt32(res, res); |
| 2622 | } |
| 2623 | } |
| 2624 | |
| 2625 | bool MPhi::canTruncate() const { |
| 2626 | return type() == MIRType::Double || type() == MIRType::Int32; |
| 2627 | } |
| 2628 | |
| 2629 | void MPhi::truncate(TruncateKind kind) { |
| 2630 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2630); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2630; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2631 | truncateKind_ = kind; |
| 2632 | setResultType(MIRType::Int32); |
| 2633 | if (kind >= TruncateKind::IndirectTruncate && range()) { |
| 2634 | range()->wrapAroundToInt32(); |
| 2635 | } |
| 2636 | } |
| 2637 | |
| 2638 | bool MAdd::canTruncate() const { |
| 2639 | return type() == MIRType::Double || type() == MIRType::Int32; |
| 2640 | } |
| 2641 | |
| 2642 | void MAdd::truncate(TruncateKind kind) { |
| 2643 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2643); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2643; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2644 | |
| 2645 | // Remember analysis, needed for fallible checks. |
| 2646 | setTruncateKind(kind); |
| 2647 | |
| 2648 | setSpecialization(MIRType::Int32); |
| 2649 | if (truncateKind() >= TruncateKind::IndirectTruncate && range()) { |
| 2650 | range()->wrapAroundToInt32(); |
| 2651 | } |
| 2652 | } |
| 2653 | |
| 2654 | bool MSub::canTruncate() const { |
| 2655 | return type() == MIRType::Double || type() == MIRType::Int32; |
| 2656 | } |
| 2657 | |
| 2658 | void MSub::truncate(TruncateKind kind) { |
| 2659 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2659); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2659; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2660 | |
| 2661 | // Remember analysis, needed for fallible checks. |
| 2662 | setTruncateKind(kind); |
| 2663 | setSpecialization(MIRType::Int32); |
| 2664 | if (truncateKind() >= TruncateKind::IndirectTruncate && range()) { |
| 2665 | range()->wrapAroundToInt32(); |
| 2666 | } |
| 2667 | } |
| 2668 | |
| 2669 | bool MMul::canTruncate() const { |
| 2670 | return type() == MIRType::Double || type() == MIRType::Int32; |
| 2671 | } |
| 2672 | |
| 2673 | void MMul::truncate(TruncateKind kind) { |
| 2674 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2674); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2674; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2675 | |
| 2676 | // Remember analysis, needed for fallible checks. |
| 2677 | setTruncateKind(kind); |
| 2678 | setSpecialization(MIRType::Int32); |
| 2679 | if (truncateKind() >= TruncateKind::IndirectTruncate) { |
| 2680 | setCanBeNegativeZero(false); |
| 2681 | if (range()) { |
| 2682 | range()->wrapAroundToInt32(); |
| 2683 | } |
| 2684 | } |
| 2685 | } |
| 2686 | |
| 2687 | bool MDiv::canTruncate() const { |
| 2688 | return type() == MIRType::Double || type() == MIRType::Int32; |
| 2689 | } |
| 2690 | |
| 2691 | void MDiv::truncate(TruncateKind kind) { |
| 2692 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2692); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2692; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2693 | |
| 2694 | // Remember analysis, needed for fallible checks. |
| 2695 | setTruncateKind(kind); |
| 2696 | setSpecialization(MIRType::Int32); |
| 2697 | |
| 2698 | // Divisions where the lhs and rhs are unsigned and the result is |
| 2699 | // truncated can be lowered more efficiently. |
| 2700 | if (unsignedOperands()) { |
| 2701 | replaceWithUnsignedOperands(); |
| 2702 | unsigned_ = true; |
| 2703 | } |
| 2704 | } |
| 2705 | |
| 2706 | bool MMod::canTruncate() const { |
| 2707 | return type() == MIRType::Double || type() == MIRType::Int32; |
| 2708 | } |
| 2709 | |
| 2710 | void MMod::truncate(TruncateKind kind) { |
| 2711 | // As for division, handle unsigned modulus with a truncated result. |
| 2712 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2712); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2712; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2713 | |
| 2714 | // Remember analysis, needed for fallible checks. |
| 2715 | setTruncateKind(kind); |
| 2716 | setSpecialization(MIRType::Int32); |
| 2717 | |
| 2718 | if (unsignedOperands()) { |
| 2719 | replaceWithUnsignedOperands(); |
| 2720 | unsigned_ = true; |
| 2721 | } |
| 2722 | } |
| 2723 | |
| 2724 | bool MToDouble::canTruncate() const { |
| 2725 | MOZ_ASSERT(type() == MIRType::Double)do { static_assert( mozilla::detail::AssertionConditionType< decltype(type() == MIRType::Double)>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(type() == MIRType::Double))) , 0))) { do { } while (false); MOZ_ReportAssertionFailure("type() == MIRType::Double" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2725); AnnotateMozCrashReason("MOZ_ASSERT" "(" "type() == MIRType::Double" ")"); do { *((volatile int*)__null) = 2725; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2726 | return true; |
| 2727 | } |
| 2728 | |
| 2729 | void MToDouble::truncate(TruncateKind kind) { |
| 2730 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2730); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2730; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2731 | setTruncateKind(kind); |
| 2732 | |
| 2733 | // We use the return type to flag that this MToDouble should be replaced by |
| 2734 | // a MTruncateToInt32 when modifying the graph. |
| 2735 | setResultType(MIRType::Int32); |
| 2736 | if (truncateKind() >= TruncateKind::IndirectTruncate) { |
| 2737 | if (range()) { |
| 2738 | range()->wrapAroundToInt32(); |
| 2739 | } |
| 2740 | } |
| 2741 | } |
| 2742 | |
| 2743 | bool MLimitedTruncate::canTruncate() const { return true; } |
| 2744 | |
| 2745 | void MLimitedTruncate::truncate(TruncateKind kind) { |
| 2746 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2746); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2746; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2747 | setTruncateKind(kind); |
| 2748 | setResultType(MIRType::Int32); |
| 2749 | if (kind >= TruncateKind::IndirectTruncate && range()) { |
| 2750 | range()->wrapAroundToInt32(); |
| 2751 | } |
| 2752 | } |
| 2753 | |
| 2754 | bool MCompare::canTruncate() const { |
| 2755 | if (!isDoubleComparison()) { |
| 2756 | return false; |
| 2757 | } |
| 2758 | |
| 2759 | // If both operands are naturally in the int32 range, we can convert from |
| 2760 | // a double comparison to being an int32 comparison. |
| 2761 | if (!Range(lhs()).isInt32() || !Range(rhs()).isInt32()) { |
| 2762 | return false; |
| 2763 | } |
| 2764 | |
| 2765 | return true; |
| 2766 | } |
| 2767 | |
| 2768 | void MCompare::truncate(TruncateKind kind) { |
| 2769 | MOZ_ASSERT(canTruncate())do { static_assert( mozilla::detail::AssertionConditionType< decltype(canTruncate())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(canTruncate()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("canTruncate()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2769); AnnotateMozCrashReason("MOZ_ASSERT" "(" "canTruncate()" ")"); do { *((volatile int*)__null) = 2769; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2770 | compareType_ = Compare_Int32; |
| 2771 | |
| 2772 | // Truncating the operands won't change their value because we don't force a |
| 2773 | // truncation, but it will change their type, which we need because we |
| 2774 | // now expect integer inputs. |
| 2775 | truncateOperands_ = true; |
| 2776 | } |
| 2777 | |
| 2778 | TruncateKind MDefinition::operandTruncateKind(size_t index) const { |
| 2779 | // Generic routine: We don't know anything. |
| 2780 | return TruncateKind::NoTruncate; |
| 2781 | } |
| 2782 | |
| 2783 | TruncateKind MPhi::operandTruncateKind(size_t index) const { |
| 2784 | // The truncation applied to a phi is effectively applied to the phi's |
| 2785 | // operands. |
| 2786 | return truncateKind_; |
| 2787 | } |
| 2788 | |
| 2789 | TruncateKind MTruncateToInt32::operandTruncateKind(size_t index) const { |
| 2790 | // This operator is an explicit truncate to int32. |
| 2791 | return TruncateKind::Truncate; |
| 2792 | } |
| 2793 | |
| 2794 | TruncateKind MBinaryBitwiseInstruction::operandTruncateKind( |
| 2795 | size_t index) const { |
| 2796 | // The bitwise operators truncate to int32. |
| 2797 | return TruncateKind::Truncate; |
| 2798 | } |
| 2799 | |
| 2800 | TruncateKind MLimitedTruncate::operandTruncateKind(size_t index) const { |
| 2801 | return std::min(truncateKind(), truncateLimit_); |
| 2802 | } |
| 2803 | |
| 2804 | TruncateKind MAdd::operandTruncateKind(size_t index) const { |
| 2805 | // This operator is doing some arithmetic. If its result is truncated, |
| 2806 | // it's an indirect truncate for its operands. |
| 2807 | return std::min(truncateKind(), TruncateKind::IndirectTruncate); |
| 2808 | } |
| 2809 | |
| 2810 | TruncateKind MSub::operandTruncateKind(size_t index) const { |
| 2811 | // See the comment in MAdd::operandTruncateKind. |
| 2812 | return std::min(truncateKind(), TruncateKind::IndirectTruncate); |
| 2813 | } |
| 2814 | |
| 2815 | TruncateKind MMul::operandTruncateKind(size_t index) const { |
| 2816 | // See the comment in MAdd::operandTruncateKind. |
| 2817 | return std::min(truncateKind(), TruncateKind::IndirectTruncate); |
| 2818 | } |
| 2819 | |
| 2820 | TruncateKind MToDouble::operandTruncateKind(size_t index) const { |
| 2821 | // MToDouble propagates its truncate kind to its operand. |
| 2822 | return truncateKind(); |
| 2823 | } |
| 2824 | |
| 2825 | TruncateKind MStoreUnboxedScalar::operandTruncateKind(size_t index) const { |
| 2826 | // An integer store truncates the stored value. |
| 2827 | return (index == 2 && isIntegerWrite()) ? TruncateKind::Truncate |
| 2828 | : TruncateKind::NoTruncate; |
| 2829 | } |
| 2830 | |
| 2831 | TruncateKind MStoreDataViewElement::operandTruncateKind(size_t index) const { |
| 2832 | // An integer store truncates the stored value. |
| 2833 | return (index == 2 && isIntegerWrite()) ? TruncateKind::Truncate |
| 2834 | : TruncateKind::NoTruncate; |
| 2835 | } |
| 2836 | |
| 2837 | TruncateKind MStoreTypedArrayElementHole::operandTruncateKind( |
| 2838 | size_t index) const { |
| 2839 | // An integer store truncates the stored value. |
| 2840 | return (index == 3 && isIntegerWrite()) ? TruncateKind::Truncate |
| 2841 | : TruncateKind::NoTruncate; |
| 2842 | } |
| 2843 | |
| 2844 | TruncateKind MDiv::operandTruncateKind(size_t index) const { |
| 2845 | return std::min(truncateKind(), TruncateKind::TruncateAfterBailouts); |
| 2846 | } |
| 2847 | |
| 2848 | TruncateKind MMod::operandTruncateKind(size_t index) const { |
| 2849 | return std::min(truncateKind(), TruncateKind::TruncateAfterBailouts); |
| 2850 | } |
| 2851 | |
| 2852 | TruncateKind MCompare::operandTruncateKind(size_t index) const { |
| 2853 | // If we're doing an int32 comparison on operands which were previously |
| 2854 | // floating-point, convert them! |
| 2855 | MOZ_ASSERT_IF(truncateOperands_, isInt32Comparison())do { if (truncateOperands_) { do { static_assert( mozilla::detail ::AssertionConditionType<decltype(isInt32Comparison())> ::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(isInt32Comparison()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("isInt32Comparison()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2855); AnnotateMozCrashReason("MOZ_ASSERT" "(" "isInt32Comparison()" ")"); do { *((volatile int*)__null) = 2855; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); } } while ( false); |
| 2856 | return truncateOperands_ ? TruncateKind::TruncateAfterBailouts |
| 2857 | : TruncateKind::NoTruncate; |
| 2858 | } |
| 2859 | |
| 2860 | static bool TruncateTest(TempAllocator& alloc, MTest* test) { |
| 2861 | // If all possible inputs to the test are either int32 or boolean, |
| 2862 | // convert those inputs to int32 so that an int32 test can be performed. |
| 2863 | |
| 2864 | if (test->input()->type() != MIRType::Value) { |
| 2865 | return true; |
| 2866 | } |
| 2867 | |
| 2868 | if (!test->input()->isPhi() || !test->input()->hasOneDefUse() || |
| 2869 | test->input()->isImplicitlyUsed()) { |
| 2870 | return true; |
| 2871 | } |
| 2872 | |
| 2873 | MPhi* phi = test->input()->toPhi(); |
| 2874 | for (size_t i = 0; i < phi->numOperands(); i++) { |
| 2875 | MDefinition* def = phi->getOperand(i); |
| 2876 | if (!def->isBox()) { |
| 2877 | return true; |
| 2878 | } |
| 2879 | MDefinition* inner = def->getOperand(0); |
| 2880 | if (inner->type() != MIRType::Boolean && inner->type() != MIRType::Int32) { |
| 2881 | return true; |
| 2882 | } |
| 2883 | } |
| 2884 | |
| 2885 | for (size_t i = 0; i < phi->numOperands(); i++) { |
| 2886 | MDefinition* inner = phi->getOperand(i)->getOperand(0); |
| 2887 | if (inner->type() != MIRType::Int32) { |
| 2888 | if (!alloc.ensureBallast()) { |
| 2889 | return false; |
| 2890 | } |
| 2891 | MBasicBlock* block = inner->block(); |
| 2892 | inner = MToNumberInt32::New(alloc, inner); |
| 2893 | block->insertBefore(block->lastIns(), inner->toInstruction()); |
| 2894 | } |
| 2895 | MOZ_ASSERT(inner->type() == MIRType::Int32)do { static_assert( mozilla::detail::AssertionConditionType< decltype(inner->type() == MIRType::Int32)>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(inner->type() == MIRType:: Int32))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("inner->type() == MIRType::Int32", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2895); AnnotateMozCrashReason("MOZ_ASSERT" "(" "inner->type() == MIRType::Int32" ")"); do { *((volatile int*)__null) = 2895; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2896 | phi->replaceOperand(i, inner); |
| 2897 | } |
| 2898 | |
| 2899 | phi->setResultType(MIRType::Int32); |
| 2900 | return true; |
| 2901 | } |
| 2902 | |
| 2903 | // Truncating instruction result is an optimization which implies |
| 2904 | // knowing all uses of an instruction. This implies that if one of |
| 2905 | // the uses got removed, then Range Analysis is not be allowed to do |
| 2906 | // any modification which can change the result, especially if the |
| 2907 | // result can be observed. |
| 2908 | // |
| 2909 | // This corner can easily be understood with UCE examples, but it |
| 2910 | // might also happen with type inference assumptions. Note: Type |
| 2911 | // inference is implicitly branches where other types might be |
| 2912 | // flowing into. |
| 2913 | static bool CloneForDeadBranches(TempAllocator& alloc, |
| 2914 | MInstruction* candidate) { |
| 2915 | // Compare returns a boolean so it doesn't have to be recovered on bailout |
| 2916 | // because the output would remain correct. |
| 2917 | if (candidate->isCompare()) { |
| 2918 | return true; |
| 2919 | } |
| 2920 | |
| 2921 | MOZ_ASSERT(candidate->canClone())do { static_assert( mozilla::detail::AssertionConditionType< decltype(candidate->canClone())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(candidate->canClone()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("candidate->canClone()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2921); AnnotateMozCrashReason("MOZ_ASSERT" "(" "candidate->canClone()" ")"); do { *((volatile int*)__null) = 2921; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2922 | if (!alloc.ensureBallast()) { |
| 2923 | return false; |
| 2924 | } |
| 2925 | |
| 2926 | MDefinitionVector operands(alloc); |
| 2927 | size_t end = candidate->numOperands(); |
| 2928 | if (!operands.reserve(end)) { |
| 2929 | return false; |
| 2930 | } |
| 2931 | for (size_t i = 0; i < end; ++i) { |
| 2932 | operands.infallibleAppend(candidate->getOperand(i)); |
| 2933 | } |
| 2934 | |
| 2935 | MInstruction* clone = candidate->clone(alloc, operands); |
| 2936 | if (!clone) { |
| 2937 | return false; |
| 2938 | } |
| 2939 | clone->setRange(nullptr); |
| 2940 | |
| 2941 | // Set ImplicitlyUsed flag on the cloned instruction in order to chain recover |
| 2942 | // instruction for the bailout path. |
| 2943 | clone->setImplicitlyUsedUnchecked(); |
| 2944 | |
| 2945 | candidate->block()->insertBefore(candidate, clone); |
| 2946 | |
| 2947 | if (!candidate->maybeConstantValue()) { |
| 2948 | MOZ_ASSERT(clone->canRecoverOnBailout())do { static_assert( mozilla::detail::AssertionConditionType< decltype(clone->canRecoverOnBailout())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(clone->canRecoverOnBailout ()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("clone->canRecoverOnBailout()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 2948); AnnotateMozCrashReason("MOZ_ASSERT" "(" "clone->canRecoverOnBailout()" ")"); do { *((volatile int*)__null) = 2948; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 2949 | clone->setRecoveredOnBailout(); |
| 2950 | } |
| 2951 | |
| 2952 | // Replace the candidate by its recovered on bailout clone within recovered |
| 2953 | // instructions and resume points operands. |
| 2954 | for (MUseIterator i(candidate->usesBegin()); i != candidate->usesEnd();) { |
| 2955 | MUse* use = *i++; |
| 2956 | MNode* ins = use->consumer(); |
| 2957 | if (ins->isDefinition() && !ins->toDefinition()->isRecoveredOnBailout()) { |
| 2958 | continue; |
| 2959 | } |
| 2960 | |
| 2961 | use->replaceProducer(clone); |
| 2962 | } |
| 2963 | |
| 2964 | return true; |
| 2965 | } |
| 2966 | |
| 2967 | // Examine all the users of |candidate| and determine the most aggressive |
| 2968 | // truncate kind that satisfies all of them. |
| 2969 | static TruncateKind ComputeRequestedTruncateKind(MDefinition* candidate, |
| 2970 | bool* shouldClone) { |
| 2971 | bool isCapturedResult = |
| 2972 | false; // Check if used by a recovered instruction or a resume point. |
| 2973 | bool isObservableResult = |
| 2974 | false; // Check if it can be read from another frame. |
| 2975 | bool isRecoverableResult = true; // Check if it can safely be reconstructed. |
| 2976 | bool isImplicitlyUsed = candidate->isImplicitlyUsed(); |
| 2977 | bool hasTryBlock = candidate->block()->graph().hasTryBlock(); |
| 2978 | |
| 2979 | TruncateKind kind = TruncateKind::Truncate; |
| 2980 | for (MUseIterator use(candidate->usesBegin()); use != candidate->usesEnd(); |
| 2981 | use++) { |
| 2982 | if (use->consumer()->isResumePoint()) { |
| 2983 | // Truncation is a destructive optimization, as such, we need to pay |
| 2984 | // attention to removed branches and prevent optimization |
| 2985 | // destructive optimizations if we have no alternative. (see |
| 2986 | // ImplicitlyUsed flag) |
| 2987 | isCapturedResult = true; |
| 2988 | isObservableResult = |
| 2989 | isObservableResult || |
| 2990 | use->consumer()->toResumePoint()->isObservableOperand(*use); |
| 2991 | isRecoverableResult = |
| 2992 | isRecoverableResult && |
| 2993 | use->consumer()->toResumePoint()->isRecoverableOperand(*use); |
| 2994 | continue; |
| 2995 | } |
| 2996 | |
| 2997 | MDefinition* consumer = use->consumer()->toDefinition(); |
| 2998 | if (consumer->isRecoveredOnBailout()) { |
| 2999 | isCapturedResult = true; |
| 3000 | isImplicitlyUsed = isImplicitlyUsed || consumer->isImplicitlyUsed(); |
| 3001 | continue; |
| 3002 | } |
| 3003 | |
| 3004 | TruncateKind consumerKind = |
| 3005 | consumer->operandTruncateKind(consumer->indexOf(*use)); |
| 3006 | kind = std::min(kind, consumerKind); |
| 3007 | if (kind == TruncateKind::NoTruncate) { |
| 3008 | break; |
| 3009 | } |
| 3010 | } |
| 3011 | |
| 3012 | // We cannot do full trunction on guarded instructions. |
| 3013 | if (candidate->isGuard() || candidate->isGuardRangeBailouts()) { |
| 3014 | kind = std::min(kind, TruncateKind::TruncateAfterBailouts); |
| 3015 | } |
| 3016 | |
| 3017 | // If the value naturally produces an int32 value (before bailout checks) |
| 3018 | // that needs no conversion, we don't have to worry about resume points |
| 3019 | // seeing truncated values. |
| 3020 | bool needsConversion = !candidate->range() || !candidate->range()->isInt32(); |
| 3021 | |
| 3022 | // If the instruction is explicitly truncated (not indirectly) by all its |
| 3023 | // uses and if it is not implicitly used, then we can safely encode its |
| 3024 | // truncated result as part of the resume point operands. This is safe, |
| 3025 | // because even if we resume with a truncated double, the next baseline |
| 3026 | // instruction operating on this instruction is going to be a no-op. |
| 3027 | // |
| 3028 | // Note, that if the result can be observed from another frame, then this |
| 3029 | // optimization is not safe. Similarly, if this function contains a try |
| 3030 | // block, the result could be observed from a catch block, which we do |
| 3031 | // not compile. |
| 3032 | bool safeToConvert = kind == TruncateKind::Truncate && !isImplicitlyUsed && |
| 3033 | !isObservableResult && !hasTryBlock; |
| 3034 | |
| 3035 | // If the candidate instruction appears as operand of a resume point or a |
| 3036 | // recover instruction, and we have to truncate its result, then we might |
| 3037 | // have to either recover the result during the bailout, or avoid the |
| 3038 | // truncation. |
| 3039 | if (isCapturedResult && needsConversion && !safeToConvert) { |
| 3040 | // If the result can be recovered from all the resume points (not needed |
| 3041 | // for iterating over the inlined frames), and this instruction can be |
| 3042 | // recovered on bailout, then we can clone it and use the cloned |
| 3043 | // instruction to encode the recover instruction. Otherwise, we should |
| 3044 | // keep the original result and bailout if the value is not in the int32 |
| 3045 | // range. |
| 3046 | if (!JitOptions.disableRecoverIns && isRecoverableResult && |
| 3047 | candidate->canRecoverOnBailout()) { |
| 3048 | *shouldClone = true; |
| 3049 | } else { |
| 3050 | kind = std::min(kind, TruncateKind::TruncateAfterBailouts); |
| 3051 | } |
| 3052 | } |
| 3053 | |
| 3054 | return kind; |
| 3055 | } |
| 3056 | |
| 3057 | static TruncateKind ComputeTruncateKind(MDefinition* candidate, |
| 3058 | bool* shouldClone) { |
| 3059 | // Compare operations might coerce its inputs to int32 if the ranges are |
| 3060 | // correct. So we do not need to check if all uses are coerced. |
| 3061 | if (candidate->isCompare()) { |
| 3062 | return TruncateKind::TruncateAfterBailouts; |
| 3063 | } |
| 3064 | |
| 3065 | // Set truncated flag if range analysis ensure that it has no |
| 3066 | // rounding errors and no fractional part. Note that we can't use |
| 3067 | // the MDefinition Range constructor, because we need to know if |
| 3068 | // the value will have rounding errors before any bailout checks. |
| 3069 | const Range* r = candidate->range(); |
| 3070 | bool canHaveRoundingErrors = !r || r->canHaveRoundingErrors(); |
| 3071 | |
| 3072 | // Special case integer division and modulo: a/b can be infinite, and a%b |
| 3073 | // can be NaN but cannot actually have rounding errors induced by truncation. |
| 3074 | if ((candidate->isDiv() || candidate->isMod()) && |
| 3075 | candidate->type() == MIRType::Int32) { |
| 3076 | canHaveRoundingErrors = false; |
| 3077 | } |
| 3078 | |
| 3079 | if (canHaveRoundingErrors) { |
| 3080 | return TruncateKind::NoTruncate; |
| 3081 | } |
| 3082 | |
| 3083 | // Ensure all observable uses are truncated. |
| 3084 | return ComputeRequestedTruncateKind(candidate, shouldClone); |
| 3085 | } |
| 3086 | |
| 3087 | static void RemoveTruncatesOnOutput(MDefinition* truncated) { |
| 3088 | // Compare returns a boolean so it doen't have any output truncates. |
| 3089 | if (truncated->isCompare()) { |
| 3090 | return; |
| 3091 | } |
| 3092 | |
| 3093 | MOZ_ASSERT(truncated->type() == MIRType::Int32)do { static_assert( mozilla::detail::AssertionConditionType< decltype(truncated->type() == MIRType::Int32)>::isValid , "invalid assertion condition"); if ((__builtin_expect(!!(!( !!(truncated->type() == MIRType::Int32))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("truncated->type() == MIRType::Int32" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 3093); AnnotateMozCrashReason("MOZ_ASSERT" "(" "truncated->type() == MIRType::Int32" ")"); do { *((volatile int*)__null) = 3093; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 3094 | MOZ_ASSERT(Range(truncated).isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(Range(truncated).isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(Range(truncated).isInt32())) ), 0))) { do { } while (false); MOZ_ReportAssertionFailure("Range(truncated).isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 3094); AnnotateMozCrashReason("MOZ_ASSERT" "(" "Range(truncated).isInt32()" ")"); do { *((volatile int*)__null) = 3094; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 3095 | |
| 3096 | for (MUseDefIterator use(truncated); use; use++) { |
| 3097 | MDefinition* def = use.def(); |
| 3098 | if (!def->isTruncateToInt32() || !def->isToNumberInt32()) { |
| 3099 | continue; |
| 3100 | } |
| 3101 | |
| 3102 | def->replaceAllUsesWith(truncated); |
| 3103 | } |
| 3104 | } |
| 3105 | |
| 3106 | void RangeAnalysis::adjustTruncatedInputs(MDefinition* truncated) { |
| 3107 | MBasicBlock* block = truncated->block(); |
| 3108 | for (size_t i = 0, e = truncated->numOperands(); i < e; i++) { |
| 3109 | TruncateKind kind = truncated->operandTruncateKind(i); |
| 3110 | if (kind == TruncateKind::NoTruncate) { |
| 3111 | continue; |
| 3112 | } |
| 3113 | |
| 3114 | MDefinition* input = truncated->getOperand(i); |
| 3115 | if (input->type() == MIRType::Int32) { |
| 3116 | continue; |
| 3117 | } |
| 3118 | |
| 3119 | if (input->isToDouble() && input->getOperand(0)->type() == MIRType::Int32) { |
| 3120 | truncated->replaceOperand(i, input->getOperand(0)); |
| 3121 | } else { |
| 3122 | MInstruction* op; |
| 3123 | if (kind == TruncateKind::TruncateAfterBailouts) { |
| 3124 | MOZ_ASSERT(!mir->outerInfo().hadEagerTruncationBailout())do { static_assert( mozilla::detail::AssertionConditionType< decltype(!mir->outerInfo().hadEagerTruncationBailout())> ::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(!mir->outerInfo().hadEagerTruncationBailout()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("!mir->outerInfo().hadEagerTruncationBailout()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 3124); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!mir->outerInfo().hadEagerTruncationBailout()" ")"); do { *((volatile int*)__null) = 3124; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 3125 | op = MToNumberInt32::New(alloc(), truncated->getOperand(i)); |
| 3126 | op->setBailoutKind(BailoutKind::EagerTruncation); |
| 3127 | } else { |
| 3128 | op = MTruncateToInt32::New(alloc(), truncated->getOperand(i)); |
| 3129 | } |
| 3130 | |
| 3131 | if (truncated->isPhi()) { |
| 3132 | MBasicBlock* pred = block->getPredecessor(i); |
| 3133 | pred->insertBefore(pred->lastIns(), op); |
| 3134 | } else { |
| 3135 | block->insertBefore(truncated->toInstruction(), op); |
| 3136 | } |
| 3137 | truncated->replaceOperand(i, op); |
| 3138 | } |
| 3139 | } |
| 3140 | |
| 3141 | if (truncated->isToDouble()) { |
| 3142 | truncated->replaceAllUsesWith(truncated->toToDouble()->getOperand(0)); |
| 3143 | block->discard(truncated->toToDouble()); |
| 3144 | } |
| 3145 | } |
| 3146 | |
| 3147 | bool RangeAnalysis::canTruncate(MDefinition* def, TruncateKind kind) const { |
| 3148 | if (kind == TruncateKind::NoTruncate) { |
| 3149 | return false; |
| 3150 | } |
| 3151 | |
| 3152 | // Range Analysis is sometimes eager to do optimizations, even if we |
| 3153 | // are not able to truncate an instruction. In such case, we |
| 3154 | // speculatively compile the instruction to an int32 instruction |
| 3155 | // while adding a guard. This is what is implied by |
| 3156 | // TruncateAfterBailout. |
| 3157 | // |
| 3158 | // If a previous compilation was invalidated because a speculative |
| 3159 | // truncation bailed out, we no longer attempt to make this kind of |
| 3160 | // eager optimization. |
| 3161 | if (mir->outerInfo().hadEagerTruncationBailout()) { |
| 3162 | if (kind == TruncateKind::TruncateAfterBailouts) { |
| 3163 | return false; |
| 3164 | } |
| 3165 | // MDiv and MMod always require TruncateAfterBailout for their operands. |
| 3166 | // See MDiv::operandTruncateKind and MMod::operandTruncateKind. |
| 3167 | if (def->isDiv() || def->isMod()) { |
| 3168 | return false; |
| 3169 | } |
| 3170 | } |
| 3171 | |
| 3172 | return true; |
| 3173 | } |
| 3174 | |
| 3175 | // Iterate backward on all instruction and attempt to truncate operations for |
| 3176 | // each instruction which respect the following list of predicates: Has been |
| 3177 | // analyzed by range analysis, the range has no rounding errors, all uses cases |
| 3178 | // are truncating the result. |
| 3179 | // |
| 3180 | // If the truncation of the operation is successful, then the instruction is |
| 3181 | // queue for later updating the graph to restore the type correctness by |
| 3182 | // converting the operands that need to be truncated. |
| 3183 | // |
| 3184 | // We iterate backward because it is likely that a truncated operation truncates |
| 3185 | // some of its operands. |
| 3186 | bool RangeAnalysis::truncate() { |
| 3187 | JitSpew(JitSpew_Range, "Do range-base truncation (backward loop)"); |
| 3188 | |
| 3189 | // Automatic truncation is disabled for wasm because the truncation logic |
| 3190 | // is based on IonMonkey which assumes that we can bailout if the truncation |
| 3191 | // logic fails. As wasm code has no bailout mechanism, it is safer to avoid |
| 3192 | // any automatic truncations. |
| 3193 | MOZ_ASSERT(!mir->compilingWasm())do { static_assert( mozilla::detail::AssertionConditionType< decltype(!mir->compilingWasm())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(!mir->compilingWasm()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("!mir->compilingWasm()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 3193); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!mir->compilingWasm()" ")"); do { *((volatile int*)__null) = 3193; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 3194 | |
| 3195 | Vector<MDefinition*, 16, SystemAllocPolicy> worklist; |
| 3196 | |
| 3197 | for (PostorderIterator block(graph_.poBegin()); block != graph_.poEnd(); |
| 3198 | block++) { |
| 3199 | for (MInstructionReverseIterator iter(block->rbegin()); |
| 3200 | iter != block->rend(); iter++) { |
| 3201 | if (iter->isRecoveredOnBailout()) { |
| 3202 | continue; |
| 3203 | } |
| 3204 | |
| 3205 | if (iter->type() == MIRType::None) { |
| 3206 | if (iter->isTest()) { |
| 3207 | if (!TruncateTest(alloc(), iter->toTest())) { |
| 3208 | return false; |
| 3209 | } |
| 3210 | } |
| 3211 | continue; |
| 3212 | } |
| 3213 | |
| 3214 | // Remember all bitop instructions for folding after range analysis. |
| 3215 | switch (iter->op()) { |
| 3216 | case MDefinition::Opcode::BitAnd: |
| 3217 | case MDefinition::Opcode::BitOr: |
| 3218 | case MDefinition::Opcode::BitXor: |
| 3219 | case MDefinition::Opcode::Lsh: |
| 3220 | case MDefinition::Opcode::Rsh: |
| 3221 | case MDefinition::Opcode::Ursh: |
| 3222 | if (!bitops.append(static_cast<MBinaryBitwiseInstruction*>(*iter))) { |
| 3223 | return false; |
| 3224 | } |
| 3225 | break; |
| 3226 | default:; |
| 3227 | } |
| 3228 | |
| 3229 | bool shouldClone = false; |
| 3230 | TruncateKind kind = ComputeTruncateKind(*iter, &shouldClone); |
| 3231 | |
| 3232 | // Truncate this instruction if possible. |
| 3233 | if (!canTruncate(*iter, kind) || !iter->canTruncate()) { |
| 3234 | continue; |
| 3235 | } |
| 3236 | |
| 3237 | SpewTruncate(*iter, kind, shouldClone); |
| 3238 | |
| 3239 | // If needed, clone the current instruction for keeping it for the |
| 3240 | // bailout path. This give us the ability to truncate instructions |
| 3241 | // even after the removal of branches. |
| 3242 | if (shouldClone && !CloneForDeadBranches(alloc(), *iter)) { |
| 3243 | return false; |
| 3244 | } |
| 3245 | |
| 3246 | // TruncateAfterBailouts keeps the bailout code as-is and |
| 3247 | // continues with truncated operations, with the expectation |
| 3248 | // that we are unlikely to bail out. If we do bail out, then we |
| 3249 | // will set a flag in FinishBailoutToBaseline to prevent eager |
| 3250 | // truncation when we recompile, to avoid bailout loops. |
| 3251 | if (kind == TruncateKind::TruncateAfterBailouts) { |
| 3252 | iter->setBailoutKind(BailoutKind::EagerTruncation); |
| 3253 | } |
| 3254 | |
| 3255 | iter->truncate(kind); |
| 3256 | |
| 3257 | // Delay updates of inputs/outputs to avoid creating node which |
| 3258 | // would be removed by the truncation of the next operations. |
| 3259 | iter->setInWorklist(); |
| 3260 | if (!worklist.append(*iter)) { |
| 3261 | return false; |
| 3262 | } |
| 3263 | } |
| 3264 | for (MPhiIterator iter(block->phisBegin()), end(block->phisEnd()); |
| 3265 | iter != end; ++iter) { |
| 3266 | bool shouldClone = false; |
| 3267 | TruncateKind kind = ComputeTruncateKind(*iter, &shouldClone); |
| 3268 | |
| 3269 | // Truncate this phi if possible. |
| 3270 | if (shouldClone || !canTruncate(*iter, kind) || !iter->canTruncate()) { |
| 3271 | continue; |
| 3272 | } |
| 3273 | |
| 3274 | SpewTruncate(*iter, kind, shouldClone); |
| 3275 | |
| 3276 | iter->truncate(kind); |
| 3277 | |
| 3278 | // Delay updates of inputs/outputs to avoid creating node which |
| 3279 | // would be removed by the truncation of the next operations. |
| 3280 | iter->setInWorklist(); |
| 3281 | if (!worklist.append(*iter)) { |
| 3282 | return false; |
| 3283 | } |
| 3284 | } |
| 3285 | } |
| 3286 | |
| 3287 | // Update inputs/outputs of truncated instructions. |
| 3288 | JitSpew(JitSpew_Range, "Do graph type fixup (dequeue)"); |
| 3289 | while (!worklist.empty()) { |
| 3290 | if (!alloc().ensureBallast()) { |
| 3291 | return false; |
| 3292 | } |
| 3293 | MDefinition* def = worklist.popCopy(); |
| 3294 | def->setNotInWorklist(); |
| 3295 | RemoveTruncatesOnOutput(def); |
| 3296 | adjustTruncatedInputs(def); |
| 3297 | } |
| 3298 | |
| 3299 | return true; |
| 3300 | } |
| 3301 | |
| 3302 | bool RangeAnalysis::removeUnnecessaryBitops() { |
| 3303 | JitSpew(JitSpew_Range, "Begin (removeUnnecessaryBitops)"); |
| 3304 | // Note: This operation change the semantic of the program in a way which |
| 3305 | // uniquely works with Int32, Recover Instructions added by the Sink phase |
| 3306 | // expects the MIR Graph to still have a valid flow as-if they were double |
| 3307 | // operations instead of Int32 operations. Thus, this phase should be |
| 3308 | // executed after the Sink phase, and before DCE. |
| 3309 | |
| 3310 | // Fold any unnecessary bitops in the graph, such as (x | 0) on an integer |
| 3311 | // input. This is done after range analysis rather than during GVN as the |
| 3312 | // presence of the bitop can change which instructions are truncated. |
| 3313 | for (size_t i = 0; i < bitops.length(); i++) { |
| 3314 | MBinaryBitwiseInstruction* ins = bitops[i]; |
| 3315 | if (ins->isRecoveredOnBailout()) { |
| 3316 | continue; |
| 3317 | } |
| 3318 | |
| 3319 | MDefinition* folded = ins->foldUnnecessaryBitop(); |
| 3320 | if (folded != ins) { |
| 3321 | ins->replaceAllLiveUsesWith(folded); |
| 3322 | ins->setRecoveredOnBailout(); |
| 3323 | } |
| 3324 | } |
| 3325 | |
| 3326 | bitops.clear(); |
| 3327 | return true; |
| 3328 | } |
| 3329 | |
| 3330 | /////////////////////////////////////////////////////////////////////////////// |
| 3331 | // Collect Range information of operands |
| 3332 | /////////////////////////////////////////////////////////////////////////////// |
| 3333 | |
| 3334 | void MInArray::collectRangeInfoPreTrunc() { |
| 3335 | Range indexRange(index()); |
| 3336 | if (indexRange.isFiniteNonNegative()) { |
| 3337 | needsNegativeIntCheck_ = false; |
| 3338 | setNotGuard(); |
| 3339 | } |
| 3340 | } |
| 3341 | |
| 3342 | void MLoadElementHole::collectRangeInfoPreTrunc() { |
| 3343 | Range indexRange(index()); |
| 3344 | if (indexRange.isFiniteNonNegative()) { |
| 3345 | needsNegativeIntCheck_ = false; |
| 3346 | setNotGuard(); |
| 3347 | } |
| 3348 | } |
| 3349 | |
| 3350 | void MInt32ToIntPtr::collectRangeInfoPreTrunc() { |
| 3351 | Range inputRange(input()); |
| 3352 | if (inputRange.isFiniteNonNegative()) { |
| 3353 | canBeNegative_ = false; |
| 3354 | } |
| 3355 | } |
| 3356 | |
| 3357 | void MClz::collectRangeInfoPreTrunc() { |
| 3358 | Range inputRange(input()); |
| 3359 | if (!inputRange.canBeZero()) { |
| 3360 | operandIsNeverZero_ = true; |
| 3361 | } |
| 3362 | } |
| 3363 | |
| 3364 | void MCtz::collectRangeInfoPreTrunc() { |
| 3365 | Range inputRange(input()); |
| 3366 | if (!inputRange.canBeZero()) { |
| 3367 | operandIsNeverZero_ = true; |
| 3368 | } |
| 3369 | } |
| 3370 | |
| 3371 | void MDiv::collectRangeInfoPreTrunc() { |
| 3372 | Range lhsRange(lhs()); |
| 3373 | Range rhsRange(rhs()); |
| 3374 | |
| 3375 | // Test if Dividend is non-negative. |
| 3376 | if (lhsRange.isFiniteNonNegative()) { |
| 3377 | canBeNegativeDividend_ = false; |
| 3378 | } |
| 3379 | |
| 3380 | // Try removing divide by zero check. |
| 3381 | if (!rhsRange.canBeZero()) { |
| 3382 | canBeDivideByZero_ = false; |
| 3383 | } |
| 3384 | |
| 3385 | // If lhsRange does not contain INT32_MIN in its range, |
| 3386 | // negative overflow check can be skipped. |
| 3387 | if (!lhsRange.contains(INT32_MIN(-2147483647-1))) { |
| 3388 | canBeNegativeOverflow_ = false; |
| 3389 | } |
| 3390 | |
| 3391 | // If rhsRange does not contain -1 likewise. |
| 3392 | if (!rhsRange.contains(-1)) { |
| 3393 | canBeNegativeOverflow_ = false; |
| 3394 | } |
| 3395 | |
| 3396 | // If lhsRange does not contain a zero, |
| 3397 | // negative zero check can be skipped. |
| 3398 | if (!lhsRange.canBeZero()) { |
| 3399 | canBeNegativeZero_ = false; |
| 3400 | } |
| 3401 | |
| 3402 | // If rhsRange >= 0 negative zero check can be skipped. |
| 3403 | if (rhsRange.isFiniteNonNegative()) { |
| 3404 | canBeNegativeZero_ = false; |
| 3405 | } |
| 3406 | |
| 3407 | if (type() == MIRType::Int32 && fallible()) { |
| 3408 | setGuardRangeBailoutsUnchecked(); |
| 3409 | } |
| 3410 | } |
| 3411 | |
| 3412 | void MMul::collectRangeInfoPreTrunc() { |
| 3413 | Range lhsRange(lhs()); |
| 3414 | Range rhsRange(rhs()); |
| 3415 | |
| 3416 | // If lhsRange contains only positive then we can skip negative zero check. |
| 3417 | if (lhsRange.isFiniteNonNegative() && !lhsRange.canBeZero()) { |
| 3418 | setCanBeNegativeZero(false); |
| 3419 | } |
| 3420 | |
| 3421 | // Likewise rhsRange. |
| 3422 | if (rhsRange.isFiniteNonNegative() && !rhsRange.canBeZero()) { |
| 3423 | setCanBeNegativeZero(false); |
| 3424 | } |
| 3425 | |
| 3426 | // If rhsRange and lhsRange contain Non-negative integers only, |
| 3427 | // We skip negative zero check. |
| 3428 | if (rhsRange.isFiniteNonNegative() && lhsRange.isFiniteNonNegative()) { |
| 3429 | setCanBeNegativeZero(false); |
| 3430 | } |
| 3431 | |
| 3432 | // If rhsRange and lhsRange < 0. Then we skip negative zero check. |
| 3433 | if (rhsRange.isFiniteNegative() && lhsRange.isFiniteNegative()) { |
| 3434 | setCanBeNegativeZero(false); |
| 3435 | } |
| 3436 | } |
| 3437 | |
| 3438 | void MMod::collectRangeInfoPreTrunc() { |
| 3439 | Range lhsRange(lhs()); |
| 3440 | Range rhsRange(rhs()); |
| 3441 | if (lhsRange.isFiniteNonNegative()) { |
| 3442 | canBeNegativeDividend_ = false; |
| 3443 | } |
| 3444 | if (!rhsRange.canBeZero()) { |
| 3445 | canBeDivideByZero_ = false; |
| 3446 | } |
| 3447 | if (type() == MIRType::Int32 && fallible()) { |
| 3448 | setGuardRangeBailoutsUnchecked(); |
| 3449 | } |
| 3450 | } |
| 3451 | |
| 3452 | void MToNumberInt32::collectRangeInfoPreTrunc() { |
| 3453 | Range inputRange(input()); |
| 3454 | if (!inputRange.canBeNegativeZero()) { |
| 3455 | needsNegativeZeroCheck_ = false; |
| 3456 | } |
| 3457 | } |
| 3458 | |
| 3459 | void MBoundsCheck::collectRangeInfoPreTrunc() { |
| 3460 | Range indexRange(index()); |
| 3461 | Range lengthRange(length()); |
| 3462 | if (!indexRange.hasInt32LowerBound() || !indexRange.hasInt32UpperBound()) { |
| 3463 | return; |
| 3464 | } |
| 3465 | if (!lengthRange.hasInt32LowerBound() || lengthRange.canBeNaN()) { |
| 3466 | return; |
| 3467 | } |
| 3468 | |
| 3469 | int64_t indexLower = indexRange.lower(); |
| 3470 | int64_t indexUpper = indexRange.upper(); |
| 3471 | int64_t lengthLower = lengthRange.lower(); |
| 3472 | int64_t min = minimum(); |
| 3473 | int64_t max = maximum(); |
| 3474 | |
| 3475 | if (indexLower + min >= 0 && indexUpper + max < lengthLower) { |
| 3476 | fallible_ = false; |
| 3477 | } |
| 3478 | } |
| 3479 | |
| 3480 | void MBoundsCheckLower::collectRangeInfoPreTrunc() { |
| 3481 | Range indexRange(index()); |
| 3482 | if (indexRange.hasInt32LowerBound() && indexRange.lower() >= minimum_) { |
| 3483 | fallible_ = false; |
| 3484 | } |
| 3485 | } |
| 3486 | |
| 3487 | void MCompare::collectRangeInfoPreTrunc() { |
| 3488 | if (!Range(lhs()).canBeNaN() && !Range(rhs()).canBeNaN()) { |
| 3489 | operandsAreNeverNaN_ = true; |
| 3490 | } |
| 3491 | } |
| 3492 | |
| 3493 | void MNot::collectRangeInfoPreTrunc() { |
| 3494 | if (!Range(input()).canBeNaN()) { |
| 3495 | operandIsNeverNaN_ = true; |
| 3496 | } |
| 3497 | } |
| 3498 | |
| 3499 | void MPowHalf::collectRangeInfoPreTrunc() { |
| 3500 | Range inputRange(input()); |
| 3501 | if (!inputRange.canBeInfiniteOrNaN() || inputRange.hasInt32LowerBound()) { |
| 3502 | operandIsNeverNegativeInfinity_ = true; |
| 3503 | } |
| 3504 | if (!inputRange.canBeNegativeZero()) { |
| 3505 | operandIsNeverNegativeZero_ = true; |
| 3506 | } |
| 3507 | if (!inputRange.canBeNaN()) { |
| 3508 | operandIsNeverNaN_ = true; |
| 3509 | } |
| 3510 | } |
| 3511 | |
| 3512 | void MUrsh::collectRangeInfoPreTrunc() { |
| 3513 | if (type() == MIRType::Int64) { |
| 3514 | return; |
| 3515 | } |
| 3516 | |
| 3517 | Range lhsRange(lhs()), rhsRange(rhs()); |
| 3518 | |
| 3519 | // As in MUrsh::computeRange(), convert the inputs. |
| 3520 | lhsRange.wrapAroundToInt32(); |
| 3521 | rhsRange.wrapAroundToShiftCount(); |
| 3522 | |
| 3523 | // If the most significant bit of our result is always going to be zero, |
| 3524 | // we can optimize by disabling bailout checks for enforcing an int32 range. |
| 3525 | if (lhsRange.lower() >= 0 || rhsRange.lower() >= 1) { |
| 3526 | bailoutsDisabled_ = true; |
| 3527 | } |
| 3528 | } |
| 3529 | |
| 3530 | static bool DoesMaskMatchRange(int32_t mask, Range& range) { |
| 3531 | // Check if range is positive, because the bitand operator in `(-3) & 0xff` |
| 3532 | // can't be eliminated. |
| 3533 | if (range.lower() >= 0) { |
| 3534 | MOZ_ASSERT(range.isInt32())do { static_assert( mozilla::detail::AssertionConditionType< decltype(range.isInt32())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(range.isInt32()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("range.isInt32()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 3534); AnnotateMozCrashReason("MOZ_ASSERT" "(" "range.isInt32()" ")"); do { *((volatile int*)__null) = 3534; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 3535 | // Check that the mask value has all bits set given the range upper bound. |
| 3536 | // Note that the upper bound does not have to be exactly the mask value. For |
| 3537 | // example, consider `x & 0xfff` where `x` is a uint8. That expression can |
| 3538 | // still be optimized to `x`. |
| 3539 | int bits = 1 + FloorLog2(range.upper()); |
| 3540 | uint32_t maskNeeded = (bits == 32) ? 0xffffffff : (uint32_t(1) << bits) - 1; |
| 3541 | if ((mask & maskNeeded) == maskNeeded) { |
| 3542 | return true; |
| 3543 | } |
| 3544 | } |
| 3545 | |
| 3546 | return false; |
| 3547 | } |
| 3548 | |
| 3549 | void MBinaryBitwiseInstruction::collectRangeInfoPreTrunc() { |
| 3550 | Range lhsRange(lhs()); |
| 3551 | Range rhsRange(rhs()); |
| 3552 | |
| 3553 | if (lhs()->isConstant() && lhs()->type() == MIRType::Int32 && |
| 3554 | DoesMaskMatchRange(lhs()->toConstant()->toInt32(), rhsRange)) { |
| 3555 | maskMatchesRightRange = true; |
| 3556 | } |
| 3557 | |
| 3558 | if (rhs()->isConstant() && rhs()->type() == MIRType::Int32 && |
| 3559 | DoesMaskMatchRange(rhs()->toConstant()->toInt32(), lhsRange)) { |
| 3560 | maskMatchesLeftRange = true; |
| 3561 | } |
| 3562 | } |
| 3563 | |
| 3564 | void MNaNToZero::collectRangeInfoPreTrunc() { |
| 3565 | Range inputRange(input()); |
| 3566 | |
| 3567 | if (!inputRange.canBeNaN()) { |
| 3568 | operandIsNeverNaN_ = true; |
| 3569 | } |
| 3570 | if (!inputRange.canBeNegativeZero()) { |
| 3571 | operandIsNeverNegativeZero_ = true; |
| 3572 | } |
| 3573 | } |
| 3574 | |
| 3575 | bool RangeAnalysis::prepareForUCE(bool* shouldRemoveDeadCode) { |
| 3576 | *shouldRemoveDeadCode = false; |
| 3577 | |
| 3578 | for (ReversePostorderIterator iter(graph_.rpoBegin()); |
| 3579 | iter != graph_.rpoEnd(); iter++) { |
| 3580 | MBasicBlock* block = *iter; |
| 3581 | |
| 3582 | if (!block->unreachable()) { |
| 3583 | continue; |
| 3584 | } |
| 3585 | |
| 3586 | // Filter out unreachable fake entries. |
| 3587 | if (block->numPredecessors() == 0) { |
| 3588 | // Ignore fixup blocks added by the Value Numbering phase, in order |
| 3589 | // to keep the dominator tree as-is when we have OSR Block which are |
| 3590 | // no longer reachable from the main entry point of the graph. |
| 3591 | MOZ_ASSERT(graph_.osrBlock())do { static_assert( mozilla::detail::AssertionConditionType< decltype(graph_.osrBlock())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(graph_.osrBlock()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure("graph_.osrBlock()" , "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 3591); AnnotateMozCrashReason("MOZ_ASSERT" "(" "graph_.osrBlock()" ")"); do { *((volatile int*)__null) = 3591; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 3592 | continue; |
| 3593 | } |
| 3594 | |
| 3595 | MControlInstruction* cond = block->getPredecessor(0)->lastIns(); |
| 3596 | if (!cond->isTest()) { |
| 3597 | continue; |
| 3598 | } |
| 3599 | |
| 3600 | // Replace the condition of the test control instruction by a constant |
| 3601 | // chosen based which of the successors has the unreachable flag which is |
| 3602 | // added by MBeta::computeRange on its own block. |
| 3603 | MTest* test = cond->toTest(); |
| 3604 | MDefinition* condition = test->input(); |
| 3605 | |
| 3606 | // If the false-branch is unreachable, then the test condition must be true. |
| 3607 | // If the true-branch is unreachable, then the test condition must be false. |
| 3608 | MOZ_ASSERT(block == test->ifTrue() || block == test->ifFalse())do { static_assert( mozilla::detail::AssertionConditionType< decltype(block == test->ifTrue() || block == test->ifFalse ())>::isValid, "invalid assertion condition"); if ((__builtin_expect (!!(!(!!(block == test->ifTrue() || block == test->ifFalse ()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("block == test->ifTrue() || block == test->ifFalse()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 3608); AnnotateMozCrashReason("MOZ_ASSERT" "(" "block == test->ifTrue() || block == test->ifFalse()" ")"); do { *((volatile int*)__null) = 3608; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 3609 | bool value = block == test->ifFalse(); |
| 3610 | MConstant* constant = |
| 3611 | MConstant::New(alloc().fallible(), BooleanValue(value)); |
| 3612 | if (!constant) { |
| 3613 | return false; |
| 3614 | } |
| 3615 | |
| 3616 | condition->setGuardRangeBailoutsUnchecked(); |
| 3617 | |
| 3618 | test->block()->insertBefore(test, constant); |
| 3619 | |
| 3620 | test->replaceOperand(0, constant); |
| 3621 | JitSpew(JitSpew_Range, |
| 3622 | "Update condition of %u to reflect unreachable branches.", |
| 3623 | test->id()); |
| 3624 | |
| 3625 | *shouldRemoveDeadCode = true; |
| 3626 | } |
| 3627 | |
| 3628 | return tryRemovingGuards(); |
| 3629 | } |
| 3630 | |
| 3631 | bool RangeAnalysis::tryRemovingGuards() { |
| 3632 | MDefinitionVector guards(alloc()); |
| 3633 | |
| 3634 | for (ReversePostorderIterator block = graph_.rpoBegin(); |
| 3635 | block != graph_.rpoEnd(); block++) { |
| 3636 | for (MDefinitionIterator iter(*block); iter; iter++) { |
| 3637 | if (!iter->isGuardRangeBailouts()) { |
| 3638 | continue; |
| 3639 | } |
| 3640 | |
| 3641 | iter->setInWorklist(); |
| 3642 | if (!guards.append(*iter)) { |
| 3643 | return false; |
| 3644 | } |
| 3645 | } |
| 3646 | } |
| 3647 | |
| 3648 | // Flag all fallible instructions which were indirectly used in the |
| 3649 | // computation of the condition, such that we do not ignore |
| 3650 | // bailout-paths which are used to shrink the input range of the |
| 3651 | // operands of the condition. |
| 3652 | for (size_t i = 0; i < guards.length(); i++) { |
| 3653 | MDefinition* guard = guards[i]; |
| 3654 | |
| 3655 | // If this ins is a guard even without guardRangeBailouts, |
| 3656 | // there is no reason in trying to hoist the guardRangeBailouts check. |
| 3657 | guard->setNotGuardRangeBailouts(); |
| 3658 | if (!DeadIfUnused(guard)) { |
| 3659 | guard->setGuardRangeBailouts(); |
| 3660 | continue; |
| 3661 | } |
| 3662 | guard->setGuardRangeBailouts(); |
| 3663 | |
| 3664 | if (!guard->isPhi()) { |
| 3665 | if (!guard->range()) { |
| 3666 | continue; |
| 3667 | } |
| 3668 | |
| 3669 | // Filter the range of the instruction based on its MIRType. |
| 3670 | Range typeFilteredRange(guard); |
| 3671 | |
| 3672 | // If the output range is updated by adding the inner range, |
| 3673 | // then the MIRType act as an effectful filter. As we do not know if |
| 3674 | // this filtered Range might change or not the result of the |
| 3675 | // previous comparison, we have to keep this instruction as a guard |
| 3676 | // because it has to bailout in order to restrict the Range to its |
| 3677 | // MIRType. |
| 3678 | if (typeFilteredRange.update(guard->range())) { |
| 3679 | continue; |
| 3680 | } |
| 3681 | } |
| 3682 | |
| 3683 | guard->setNotGuardRangeBailouts(); |
| 3684 | |
| 3685 | // Propagate the guard to its operands. |
| 3686 | for (size_t op = 0, e = guard->numOperands(); op < e; op++) { |
| 3687 | MDefinition* operand = guard->getOperand(op); |
| 3688 | |
| 3689 | // Already marked. |
| 3690 | if (operand->isInWorklist()) { |
| 3691 | continue; |
| 3692 | } |
| 3693 | |
| 3694 | MOZ_ASSERT(!operand->isGuardRangeBailouts())do { static_assert( mozilla::detail::AssertionConditionType< decltype(!operand->isGuardRangeBailouts())>::isValid, "invalid assertion condition" ); if ((__builtin_expect(!!(!(!!(!operand->isGuardRangeBailouts ()))), 0))) { do { } while (false); MOZ_ReportAssertionFailure ("!operand->isGuardRangeBailouts()", "/var/lib/jenkins/workspace/firefox-scan-build/js/src/jit/RangeAnalysis.cpp" , 3694); AnnotateMozCrashReason("MOZ_ASSERT" "(" "!operand->isGuardRangeBailouts()" ")"); do { *((volatile int*)__null) = 3694; __attribute__((nomerge )) ::abort(); } while (false); } } while (false); |
| 3695 | |
| 3696 | operand->setInWorklist(); |
| 3697 | operand->setGuardRangeBailouts(); |
| 3698 | if (!guards.append(operand)) { |
| 3699 | return false; |
| 3700 | } |
| 3701 | } |
| 3702 | } |
| 3703 | |
| 3704 | for (size_t i = 0; i < guards.length(); i++) { |
| 3705 | MDefinition* guard = guards[i]; |
| 3706 | guard->setNotInWorklist(); |
| 3707 | } |
| 3708 | |
| 3709 | return true; |
| 3710 | } |