MemoryDependenceAnalysis.cpp revision a85a66423d966bf6210daf9587dba7ec1ff8d64e
1//===- MemoryDependenceAnalysis.cpp - Mem Deps Implementation --*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements an analysis that determines, for a given memory 11// operation, what preceding memory operations it depends on. It builds on 12// alias analysis information, and tries to provide a lazy, caching interface to 13// a common kind of alias information query. 14// 15//===----------------------------------------------------------------------===// 16 17#define DEBUG_TYPE "memdep" 18#include "llvm/Analysis/MemoryDependenceAnalysis.h" 19#include "llvm/Instructions.h" 20#include "llvm/IntrinsicInst.h" 21#include "llvm/Function.h" 22#include "llvm/Analysis/AliasAnalysis.h" 23#include "llvm/Analysis/MemoryBuiltins.h" 24#include "llvm/ADT/Statistic.h" 25#include "llvm/ADT/STLExtras.h" 26#include "llvm/Support/PredIteratorCache.h" 27#include "llvm/Support/Debug.h" 28using namespace llvm; 29 30STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses"); 31STATISTIC(NumCacheDirtyNonLocal, "Number of dirty cached non-local responses"); 32STATISTIC(NumUncacheNonLocal, "Number of uncached non-local responses"); 33 34STATISTIC(NumCacheNonLocalPtr, 35 "Number of fully cached non-local ptr responses"); 36STATISTIC(NumCacheDirtyNonLocalPtr, 37 "Number of cached, but dirty, non-local ptr responses"); 38STATISTIC(NumUncacheNonLocalPtr, 39 "Number of uncached non-local ptr responses"); 40STATISTIC(NumCacheCompleteNonLocalPtr, 41 "Number of block queries that were completely cached"); 42 43char MemoryDependenceAnalysis::ID = 0; 44 45// Register this pass... 46static RegisterPass<MemoryDependenceAnalysis> X("memdep", 47 "Memory Dependence Analysis", false, true); 48 49MemoryDependenceAnalysis::MemoryDependenceAnalysis() 50: FunctionPass(&ID), PredCache(0) { 51} 52MemoryDependenceAnalysis::~MemoryDependenceAnalysis() { 53} 54 55/// Clean up memory in between runs 56void MemoryDependenceAnalysis::releaseMemory() { 57 LocalDeps.clear(); 58 NonLocalDeps.clear(); 59 NonLocalPointerDeps.clear(); 60 ReverseLocalDeps.clear(); 61 ReverseNonLocalDeps.clear(); 62 ReverseNonLocalPtrDeps.clear(); 63 PredCache->clear(); 64} 65 66 67 68/// getAnalysisUsage - Does not modify anything. It uses Alias Analysis. 69/// 70void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { 71 AU.setPreservesAll(); 72 AU.addRequiredTransitive<AliasAnalysis>(); 73} 74 75bool MemoryDependenceAnalysis::runOnFunction(Function &) { 76 AA = &getAnalysis<AliasAnalysis>(); 77 if (PredCache == 0) 78 PredCache.reset(new PredIteratorCache()); 79 return false; 80} 81 82/// RemoveFromReverseMap - This is a helper function that removes Val from 83/// 'Inst's set in ReverseMap. If the set becomes empty, remove Inst's entry. 84template <typename KeyTy> 85static void RemoveFromReverseMap(DenseMap<Instruction*, 86 SmallPtrSet<KeyTy, 4> > &ReverseMap, 87 Instruction *Inst, KeyTy Val) { 88 typename DenseMap<Instruction*, SmallPtrSet<KeyTy, 4> >::iterator 89 InstIt = ReverseMap.find(Inst); 90 assert(InstIt != ReverseMap.end() && "Reverse map out of sync?"); 91 bool Found = InstIt->second.erase(Val); 92 assert(Found && "Invalid reverse map!"); Found=Found; 93 if (InstIt->second.empty()) 94 ReverseMap.erase(InstIt); 95} 96 97 98/// getCallSiteDependencyFrom - Private helper for finding the local 99/// dependencies of a call site. 100MemDepResult MemoryDependenceAnalysis:: 101getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall, 102 BasicBlock::iterator ScanIt, BasicBlock *BB) { 103 // Walk backwards through the block, looking for dependencies 104 while (ScanIt != BB->begin()) { 105 Instruction *Inst = --ScanIt; 106 107 // If this inst is a memory op, get the pointer it accessed 108 Value *Pointer = 0; 109 uint64_t PointerSize = 0; 110 if (StoreInst *S = dyn_cast<StoreInst>(Inst)) { 111 Pointer = S->getPointerOperand(); 112 PointerSize = AA->getTypeStoreSize(S->getOperand(0)->getType()); 113 } else if (VAArgInst *V = dyn_cast<VAArgInst>(Inst)) { 114 Pointer = V->getOperand(0); 115 PointerSize = AA->getTypeStoreSize(V->getType()); 116 } else if (isFreeCall(Inst)) { 117 Pointer = Inst->getOperand(1); 118 // calls to free() erase the entire structure 119 PointerSize = ~0ULL; 120 } else if (isFreeCall(Inst)) { 121 Pointer = Inst->getOperand(0); 122 // calls to free() erase the entire structure 123 PointerSize = ~0ULL; 124 } else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) { 125 // Debug intrinsics don't cause dependences. 126 if (isa<DbgInfoIntrinsic>(Inst)) continue; 127 CallSite InstCS = CallSite::get(Inst); 128 // If these two calls do not interfere, look past it. 129 switch (AA->getModRefInfo(CS, InstCS)) { 130 case AliasAnalysis::NoModRef: 131 // If the two calls don't interact (e.g. InstCS is readnone) keep 132 // scanning. 133 continue; 134 case AliasAnalysis::Ref: 135 // If the two calls read the same memory locations and CS is a readonly 136 // function, then we have two cases: 1) the calls may not interfere with 137 // each other at all. 2) the calls may produce the same value. In case 138 // #1 we want to ignore the values, in case #2, we want to return Inst 139 // as a Def dependence. This allows us to CSE in cases like: 140 // X = strlen(P); 141 // memchr(...); 142 // Y = strlen(P); // Y = X 143 if (isReadOnlyCall) { 144 if (CS.getCalledFunction() != 0 && 145 CS.getCalledFunction() == InstCS.getCalledFunction()) 146 return MemDepResult::getDef(Inst); 147 // Ignore unrelated read/read call dependences. 148 continue; 149 } 150 // FALL THROUGH 151 default: 152 return MemDepResult::getClobber(Inst); 153 } 154 } else { 155 // Non-memory instruction. 156 continue; 157 } 158 159 if (AA->getModRefInfo(CS, Pointer, PointerSize) != AliasAnalysis::NoModRef) 160 return MemDepResult::getClobber(Inst); 161 } 162 163 // No dependence found. If this is the entry block of the function, it is a 164 // clobber, otherwise it is non-local. 165 if (BB != &BB->getParent()->getEntryBlock()) 166 return MemDepResult::getNonLocal(); 167 return MemDepResult::getClobber(ScanIt); 168} 169 170/// getPointerDependencyFrom - Return the instruction on which a memory 171/// location depends. If isLoad is true, this routine ignore may-aliases with 172/// read-only operations. 173MemDepResult MemoryDependenceAnalysis:: 174getPointerDependencyFrom(Value *MemPtr, uint64_t MemSize, bool isLoad, 175 BasicBlock::iterator ScanIt, BasicBlock *BB) { 176 177 Value* invariantTag = 0; 178 179 // Walk backwards through the basic block, looking for dependencies. 180 while (ScanIt != BB->begin()) { 181 Instruction *Inst = --ScanIt; 182 183 // If we're in an invariant region, no dependencies can be found before 184 // we pass an invariant-begin marker. 185 if (invariantTag == Inst) { 186 invariantTag = 0; 187 continue; 188 189 // If we pass an invariant-end marker, then we've just entered an invariant 190 // region and can start ignoring dependencies. 191 } else if (IntrinsicInst* II = dyn_cast<IntrinsicInst>(Inst)) { 192 if (II->getIntrinsicID() == Intrinsic::invariant_end) { 193 uint64_t invariantSize = ~0ULL; 194 if (ConstantInt* CI = dyn_cast<ConstantInt>(II->getOperand(2))) 195 invariantSize = CI->getZExtValue(); 196 197 AliasAnalysis::AliasResult R = 198 AA->alias(II->getOperand(3), invariantSize, MemPtr, MemSize); 199 if (R == AliasAnalysis::MustAlias) { 200 invariantTag = II->getOperand(1); 201 continue; 202 } 203 } 204 } 205 206 // If we're querying on a load and we're in an invariant region, we're done 207 // at this point. Nothing a load depends on can live in an invariant region. 208 if (isLoad && invariantTag) continue; 209 210 // Debug intrinsics don't cause dependences. 211 if (isa<DbgInfoIntrinsic>(Inst)) continue; 212 213 // Values depend on loads if the pointers are must aliased. This means that 214 // a load depends on another must aliased load from the same value. 215 if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) { 216 Value *Pointer = LI->getPointerOperand(); 217 uint64_t PointerSize = AA->getTypeStoreSize(LI->getType()); 218 219 // If we found a pointer, check if it could be the same as our pointer. 220 AliasAnalysis::AliasResult R = 221 AA->alias(Pointer, PointerSize, MemPtr, MemSize); 222 if (R == AliasAnalysis::NoAlias) 223 continue; 224 225 // May-alias loads don't depend on each other without a dependence. 226 if (isLoad && R == AliasAnalysis::MayAlias) 227 continue; 228 // Stores depend on may and must aliased loads, loads depend on must-alias 229 // loads. 230 return MemDepResult::getDef(Inst); 231 } 232 233 if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { 234 // There can't be stores to the value we care about inside an 235 // invariant region. 236 if (invariantTag) continue; 237 238 // If alias analysis can tell that this store is guaranteed to not modify 239 // the query pointer, ignore it. Use getModRefInfo to handle cases where 240 // the query pointer points to constant memory etc. 241 if (AA->getModRefInfo(SI, MemPtr, MemSize) == AliasAnalysis::NoModRef) 242 continue; 243 244 // Ok, this store might clobber the query pointer. Check to see if it is 245 // a must alias: in this case, we want to return this as a def. 246 Value *Pointer = SI->getPointerOperand(); 247 uint64_t PointerSize = AA->getTypeStoreSize(SI->getOperand(0)->getType()); 248 249 // If we found a pointer, check if it could be the same as our pointer. 250 AliasAnalysis::AliasResult R = 251 AA->alias(Pointer, PointerSize, MemPtr, MemSize); 252 253 if (R == AliasAnalysis::NoAlias) 254 continue; 255 if (R == AliasAnalysis::MayAlias) 256 return MemDepResult::getClobber(Inst); 257 return MemDepResult::getDef(Inst); 258 } 259 260 // If this is an allocation, and if we know that the accessed pointer is to 261 // the allocation, return Def. This means that there is no dependence and 262 // the access can be optimized based on that. For example, a load could 263 // turn into undef. 264 // Note: Only determine this to be a malloc if Inst is the malloc call, not 265 // a subsequent bitcast of the malloc call result. There can be stores to 266 // the malloced memory between the malloc call and its bitcast uses, and we 267 // need to continue scanning until the malloc call. 268 if (isa<AllocaInst>(Inst) || extractMallocCall(Inst)) { 269 Value *AccessPtr = MemPtr->getUnderlyingObject(); 270 271 if (AccessPtr == Inst || 272 AA->alias(Inst, 1, AccessPtr, 1) == AliasAnalysis::MustAlias) 273 return MemDepResult::getDef(Inst); 274 continue; 275 } 276 277 // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer. 278 switch (AA->getModRefInfo(Inst, MemPtr, MemSize)) { 279 case AliasAnalysis::NoModRef: 280 // If the call has no effect on the queried pointer, just ignore it. 281 continue; 282 case AliasAnalysis::Mod: 283 // If we're in an invariant region, we can ignore calls that ONLY 284 // modify the pointer. 285 if (invariantTag) continue; 286 return MemDepResult::getClobber(Inst); 287 case AliasAnalysis::Ref: 288 // If the call is known to never store to the pointer, and if this is a 289 // load query, we can safely ignore it (scan past it). 290 if (isLoad) 291 continue; 292 default: 293 // Otherwise, there is a potential dependence. Return a clobber. 294 return MemDepResult::getClobber(Inst); 295 } 296 } 297 298 // No dependence found. If this is the entry block of the function, it is a 299 // clobber, otherwise it is non-local. 300 if (BB != &BB->getParent()->getEntryBlock()) 301 return MemDepResult::getNonLocal(); 302 return MemDepResult::getClobber(ScanIt); 303} 304 305/// getDependency - Return the instruction on which a memory operation 306/// depends. 307MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) { 308 Instruction *ScanPos = QueryInst; 309 310 // Check for a cached result 311 MemDepResult &LocalCache = LocalDeps[QueryInst]; 312 313 // If the cached entry is non-dirty, just return it. Note that this depends 314 // on MemDepResult's default constructing to 'dirty'. 315 if (!LocalCache.isDirty()) 316 return LocalCache; 317 318 // Otherwise, if we have a dirty entry, we know we can start the scan at that 319 // instruction, which may save us some work. 320 if (Instruction *Inst = LocalCache.getInst()) { 321 ScanPos = Inst; 322 323 RemoveFromReverseMap(ReverseLocalDeps, Inst, QueryInst); 324 } 325 326 BasicBlock *QueryParent = QueryInst->getParent(); 327 328 Value *MemPtr = 0; 329 uint64_t MemSize = 0; 330 331 // Do the scan. 332 if (BasicBlock::iterator(QueryInst) == QueryParent->begin()) { 333 // No dependence found. If this is the entry block of the function, it is a 334 // clobber, otherwise it is non-local. 335 if (QueryParent != &QueryParent->getParent()->getEntryBlock()) 336 LocalCache = MemDepResult::getNonLocal(); 337 else 338 LocalCache = MemDepResult::getClobber(QueryInst); 339 } else if (StoreInst *SI = dyn_cast<StoreInst>(QueryInst)) { 340 // If this is a volatile store, don't mess around with it. Just return the 341 // previous instruction as a clobber. 342 if (SI->isVolatile()) 343 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos)); 344 else { 345 MemPtr = SI->getPointerOperand(); 346 MemSize = AA->getTypeStoreSize(SI->getOperand(0)->getType()); 347 } 348 } else if (LoadInst *LI = dyn_cast<LoadInst>(QueryInst)) { 349 // If this is a volatile load, don't mess around with it. Just return the 350 // previous instruction as a clobber. 351 if (LI->isVolatile()) 352 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos)); 353 else { 354 MemPtr = LI->getPointerOperand(); 355 MemSize = AA->getTypeStoreSize(LI->getType()); 356 } 357 } else if (isFreeCall(QueryInst)) { 358 MemPtr = QueryInst->getOperand(1); 359 // calls to free() erase the entire structure, not just a field. 360 MemSize = ~0UL; 361 } else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) { 362 CallSite QueryCS = CallSite::get(QueryInst); 363 bool isReadOnly = AA->onlyReadsMemory(QueryCS); 364 LocalCache = getCallSiteDependencyFrom(QueryCS, isReadOnly, ScanPos, 365 QueryParent); 366 } else { 367 // Non-memory instruction. 368 LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos)); 369 } 370 371 // If we need to do a pointer scan, make it happen. 372 if (MemPtr) 373 LocalCache = getPointerDependencyFrom(MemPtr, MemSize, 374 isa<LoadInst>(QueryInst), 375 ScanPos, QueryParent); 376 377 // Remember the result! 378 if (Instruction *I = LocalCache.getInst()) 379 ReverseLocalDeps[I].insert(QueryInst); 380 381 return LocalCache; 382} 383 384#ifndef NDEBUG 385/// AssertSorted - This method is used when -debug is specified to verify that 386/// cache arrays are properly kept sorted. 387static void AssertSorted(MemoryDependenceAnalysis::NonLocalDepInfo &Cache, 388 int Count = -1) { 389 if (Count == -1) Count = Cache.size(); 390 if (Count == 0) return; 391 392 for (unsigned i = 1; i != unsigned(Count); ++i) 393 assert(Cache[i-1] <= Cache[i] && "Cache isn't sorted!"); 394} 395#endif 396 397/// getNonLocalCallDependency - Perform a full dependency query for the 398/// specified call, returning the set of blocks that the value is 399/// potentially live across. The returned set of results will include a 400/// "NonLocal" result for all blocks where the value is live across. 401/// 402/// This method assumes the instruction returns a "NonLocal" dependency 403/// within its own block. 404/// 405/// This returns a reference to an internal data structure that may be 406/// invalidated on the next non-local query or when an instruction is 407/// removed. Clients must copy this data if they want it around longer than 408/// that. 409const MemoryDependenceAnalysis::NonLocalDepInfo & 410MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { 411 assert(getDependency(QueryCS.getInstruction()).isNonLocal() && 412 "getNonLocalCallDependency should only be used on calls with non-local deps!"); 413 PerInstNLInfo &CacheP = NonLocalDeps[QueryCS.getInstruction()]; 414 NonLocalDepInfo &Cache = CacheP.first; 415 416 /// DirtyBlocks - This is the set of blocks that need to be recomputed. In 417 /// the cached case, this can happen due to instructions being deleted etc. In 418 /// the uncached case, this starts out as the set of predecessors we care 419 /// about. 420 SmallVector<BasicBlock*, 32> DirtyBlocks; 421 422 if (!Cache.empty()) { 423 // Okay, we have a cache entry. If we know it is not dirty, just return it 424 // with no computation. 425 if (!CacheP.second) { 426 NumCacheNonLocal++; 427 return Cache; 428 } 429 430 // If we already have a partially computed set of results, scan them to 431 // determine what is dirty, seeding our initial DirtyBlocks worklist. 432 for (NonLocalDepInfo::iterator I = Cache.begin(), E = Cache.end(); 433 I != E; ++I) 434 if (I->second.isDirty()) 435 DirtyBlocks.push_back(I->first); 436 437 // Sort the cache so that we can do fast binary search lookups below. 438 std::sort(Cache.begin(), Cache.end()); 439 440 ++NumCacheDirtyNonLocal; 441 //cerr << "CACHED CASE: " << DirtyBlocks.size() << " dirty: " 442 // << Cache.size() << " cached: " << *QueryInst; 443 } else { 444 // Seed DirtyBlocks with each of the preds of QueryInst's block. 445 BasicBlock *QueryBB = QueryCS.getInstruction()->getParent(); 446 for (BasicBlock **PI = PredCache->GetPreds(QueryBB); *PI; ++PI) 447 DirtyBlocks.push_back(*PI); 448 NumUncacheNonLocal++; 449 } 450 451 // isReadonlyCall - If this is a read-only call, we can be more aggressive. 452 bool isReadonlyCall = AA->onlyReadsMemory(QueryCS); 453 454 SmallPtrSet<BasicBlock*, 64> Visited; 455 456 unsigned NumSortedEntries = Cache.size(); 457 DEBUG(AssertSorted(Cache)); 458 459 // Iterate while we still have blocks to update. 460 while (!DirtyBlocks.empty()) { 461 BasicBlock *DirtyBB = DirtyBlocks.back(); 462 DirtyBlocks.pop_back(); 463 464 // Already processed this block? 465 if (!Visited.insert(DirtyBB)) 466 continue; 467 468 // Do a binary search to see if we already have an entry for this block in 469 // the cache set. If so, find it. 470 DEBUG(AssertSorted(Cache, NumSortedEntries)); 471 NonLocalDepInfo::iterator Entry = 472 std::upper_bound(Cache.begin(), Cache.begin()+NumSortedEntries, 473 std::make_pair(DirtyBB, MemDepResult())); 474 if (Entry != Cache.begin() && prior(Entry)->first == DirtyBB) 475 --Entry; 476 477 MemDepResult *ExistingResult = 0; 478 if (Entry != Cache.begin()+NumSortedEntries && 479 Entry->first == DirtyBB) { 480 // If we already have an entry, and if it isn't already dirty, the block 481 // is done. 482 if (!Entry->second.isDirty()) 483 continue; 484 485 // Otherwise, remember this slot so we can update the value. 486 ExistingResult = &Entry->second; 487 } 488 489 // If the dirty entry has a pointer, start scanning from it so we don't have 490 // to rescan the entire block. 491 BasicBlock::iterator ScanPos = DirtyBB->end(); 492 if (ExistingResult) { 493 if (Instruction *Inst = ExistingResult->getInst()) { 494 ScanPos = Inst; 495 // We're removing QueryInst's use of Inst. 496 RemoveFromReverseMap(ReverseNonLocalDeps, Inst, 497 QueryCS.getInstruction()); 498 } 499 } 500 501 // Find out if this block has a local dependency for QueryInst. 502 MemDepResult Dep; 503 504 if (ScanPos != DirtyBB->begin()) { 505 Dep = getCallSiteDependencyFrom(QueryCS, isReadonlyCall,ScanPos, DirtyBB); 506 } else if (DirtyBB != &DirtyBB->getParent()->getEntryBlock()) { 507 // No dependence found. If this is the entry block of the function, it is 508 // a clobber, otherwise it is non-local. 509 Dep = MemDepResult::getNonLocal(); 510 } else { 511 Dep = MemDepResult::getClobber(ScanPos); 512 } 513 514 // If we had a dirty entry for the block, update it. Otherwise, just add 515 // a new entry. 516 if (ExistingResult) 517 *ExistingResult = Dep; 518 else 519 Cache.push_back(std::make_pair(DirtyBB, Dep)); 520 521 // If the block has a dependency (i.e. it isn't completely transparent to 522 // the value), remember the association! 523 if (!Dep.isNonLocal()) { 524 // Keep the ReverseNonLocalDeps map up to date so we can efficiently 525 // update this when we remove instructions. 526 if (Instruction *Inst = Dep.getInst()) 527 ReverseNonLocalDeps[Inst].insert(QueryCS.getInstruction()); 528 } else { 529 530 // If the block *is* completely transparent to the load, we need to check 531 // the predecessors of this block. Add them to our worklist. 532 for (BasicBlock **PI = PredCache->GetPreds(DirtyBB); *PI; ++PI) 533 DirtyBlocks.push_back(*PI); 534 } 535 } 536 537 return Cache; 538} 539 540/// getNonLocalPointerDependency - Perform a full dependency query for an 541/// access to the specified (non-volatile) memory location, returning the 542/// set of instructions that either define or clobber the value. 543/// 544/// This method assumes the pointer has a "NonLocal" dependency within its 545/// own block. 546/// 547void MemoryDependenceAnalysis:: 548getNonLocalPointerDependency(Value *Pointer, bool isLoad, BasicBlock *FromBB, 549 SmallVectorImpl<NonLocalDepEntry> &Result) { 550 assert(isa<PointerType>(Pointer->getType()) && 551 "Can't get pointer deps of a non-pointer!"); 552 Result.clear(); 553 554 // We know that the pointer value is live into FromBB find the def/clobbers 555 // from presecessors. 556 const Type *EltTy = cast<PointerType>(Pointer->getType())->getElementType(); 557 uint64_t PointeeSize = AA->getTypeStoreSize(EltTy); 558 559 // This is the set of blocks we've inspected, and the pointer we consider in 560 // each block. Because of critical edges, we currently bail out if querying 561 // a block with multiple different pointers. This can happen during PHI 562 // translation. 563 DenseMap<BasicBlock*, Value*> Visited; 564 if (!getNonLocalPointerDepFromBB(Pointer, PointeeSize, isLoad, FromBB, 565 Result, Visited, true)) 566 return; 567 Result.clear(); 568 Result.push_back(std::make_pair(FromBB, 569 MemDepResult::getClobber(FromBB->begin()))); 570} 571 572/// GetNonLocalInfoForBlock - Compute the memdep value for BB with 573/// Pointer/PointeeSize using either cached information in Cache or by doing a 574/// lookup (which may use dirty cache info if available). If we do a lookup, 575/// add the result to the cache. 576MemDepResult MemoryDependenceAnalysis:: 577GetNonLocalInfoForBlock(Value *Pointer, uint64_t PointeeSize, 578 bool isLoad, BasicBlock *BB, 579 NonLocalDepInfo *Cache, unsigned NumSortedEntries) { 580 581 // Do a binary search to see if we already have an entry for this block in 582 // the cache set. If so, find it. 583 NonLocalDepInfo::iterator Entry = 584 std::upper_bound(Cache->begin(), Cache->begin()+NumSortedEntries, 585 std::make_pair(BB, MemDepResult())); 586 if (Entry != Cache->begin() && prior(Entry)->first == BB) 587 --Entry; 588 589 MemDepResult *ExistingResult = 0; 590 if (Entry != Cache->begin()+NumSortedEntries && Entry->first == BB) 591 ExistingResult = &Entry->second; 592 593 // If we have a cached entry, and it is non-dirty, use it as the value for 594 // this dependency. 595 if (ExistingResult && !ExistingResult->isDirty()) { 596 ++NumCacheNonLocalPtr; 597 return *ExistingResult; 598 } 599 600 // Otherwise, we have to scan for the value. If we have a dirty cache 601 // entry, start scanning from its position, otherwise we scan from the end 602 // of the block. 603 BasicBlock::iterator ScanPos = BB->end(); 604 if (ExistingResult && ExistingResult->getInst()) { 605 assert(ExistingResult->getInst()->getParent() == BB && 606 "Instruction invalidated?"); 607 ++NumCacheDirtyNonLocalPtr; 608 ScanPos = ExistingResult->getInst(); 609 610 // Eliminating the dirty entry from 'Cache', so update the reverse info. 611 ValueIsLoadPair CacheKey(Pointer, isLoad); 612 RemoveFromReverseMap(ReverseNonLocalPtrDeps, ScanPos, CacheKey); 613 } else { 614 ++NumUncacheNonLocalPtr; 615 } 616 617 // Scan the block for the dependency. 618 MemDepResult Dep = getPointerDependencyFrom(Pointer, PointeeSize, isLoad, 619 ScanPos, BB); 620 621 // If we had a dirty entry for the block, update it. Otherwise, just add 622 // a new entry. 623 if (ExistingResult) 624 *ExistingResult = Dep; 625 else 626 Cache->push_back(std::make_pair(BB, Dep)); 627 628 // If the block has a dependency (i.e. it isn't completely transparent to 629 // the value), remember the reverse association because we just added it 630 // to Cache! 631 if (Dep.isNonLocal()) 632 return Dep; 633 634 // Keep the ReverseNonLocalPtrDeps map up to date so we can efficiently 635 // update MemDep when we remove instructions. 636 Instruction *Inst = Dep.getInst(); 637 assert(Inst && "Didn't depend on anything?"); 638 ValueIsLoadPair CacheKey(Pointer, isLoad); 639 ReverseNonLocalPtrDeps[Inst].insert(CacheKey); 640 return Dep; 641} 642 643/// SortNonLocalDepInfoCache - Sort the a NonLocalDepInfo cache, given a certain 644/// number of elements in the array that are already properly ordered. This is 645/// optimized for the case when only a few entries are added. 646static void 647SortNonLocalDepInfoCache(MemoryDependenceAnalysis::NonLocalDepInfo &Cache, 648 unsigned NumSortedEntries) { 649 switch (Cache.size() - NumSortedEntries) { 650 case 0: 651 // done, no new entries. 652 break; 653 case 2: { 654 // Two new entries, insert the last one into place. 655 MemoryDependenceAnalysis::NonLocalDepEntry Val = Cache.back(); 656 Cache.pop_back(); 657 MemoryDependenceAnalysis::NonLocalDepInfo::iterator Entry = 658 std::upper_bound(Cache.begin(), Cache.end()-1, Val); 659 Cache.insert(Entry, Val); 660 // FALL THROUGH. 661 } 662 case 1: 663 // One new entry, Just insert the new value at the appropriate position. 664 if (Cache.size() != 1) { 665 MemoryDependenceAnalysis::NonLocalDepEntry Val = Cache.back(); 666 Cache.pop_back(); 667 MemoryDependenceAnalysis::NonLocalDepInfo::iterator Entry = 668 std::upper_bound(Cache.begin(), Cache.end(), Val); 669 Cache.insert(Entry, Val); 670 } 671 break; 672 default: 673 // Added many values, do a full scale sort. 674 std::sort(Cache.begin(), Cache.end()); 675 break; 676 } 677} 678 679 680/// getNonLocalPointerDepFromBB - Perform a dependency query based on 681/// pointer/pointeesize starting at the end of StartBB. Add any clobber/def 682/// results to the results vector and keep track of which blocks are visited in 683/// 'Visited'. 684/// 685/// This has special behavior for the first block queries (when SkipFirstBlock 686/// is true). In this special case, it ignores the contents of the specified 687/// block and starts returning dependence info for its predecessors. 688/// 689/// This function returns false on success, or true to indicate that it could 690/// not compute dependence information for some reason. This should be treated 691/// as a clobber dependence on the first instruction in the predecessor block. 692bool MemoryDependenceAnalysis:: 693getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize, 694 bool isLoad, BasicBlock *StartBB, 695 SmallVectorImpl<NonLocalDepEntry> &Result, 696 DenseMap<BasicBlock*, Value*> &Visited, 697 bool SkipFirstBlock) { 698 699 // Look up the cached info for Pointer. 700 ValueIsLoadPair CacheKey(Pointer, isLoad); 701 702 std::pair<BBSkipFirstBlockPair, NonLocalDepInfo> *CacheInfo = 703 &NonLocalPointerDeps[CacheKey]; 704 NonLocalDepInfo *Cache = &CacheInfo->second; 705 706 // If we have valid cached information for exactly the block we are 707 // investigating, just return it with no recomputation. 708 if (CacheInfo->first == BBSkipFirstBlockPair(StartBB, SkipFirstBlock)) { 709 // We have a fully cached result for this query then we can just return the 710 // cached results and populate the visited set. However, we have to verify 711 // that we don't already have conflicting results for these blocks. Check 712 // to ensure that if a block in the results set is in the visited set that 713 // it was for the same pointer query. 714 if (!Visited.empty()) { 715 for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end(); 716 I != E; ++I) { 717 DenseMap<BasicBlock*, Value*>::iterator VI = Visited.find(I->first); 718 if (VI == Visited.end() || VI->second == Pointer) continue; 719 720 // We have a pointer mismatch in a block. Just return clobber, saying 721 // that something was clobbered in this result. We could also do a 722 // non-fully cached query, but there is little point in doing this. 723 return true; 724 } 725 } 726 727 for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end(); 728 I != E; ++I) { 729 Visited.insert(std::make_pair(I->first, Pointer)); 730 if (!I->second.isNonLocal()) 731 Result.push_back(*I); 732 } 733 ++NumCacheCompleteNonLocalPtr; 734 return false; 735 } 736 737 // Otherwise, either this is a new block, a block with an invalid cache 738 // pointer or one that we're about to invalidate by putting more info into it 739 // than its valid cache info. If empty, the result will be valid cache info, 740 // otherwise it isn't. 741 if (Cache->empty()) 742 CacheInfo->first = BBSkipFirstBlockPair(StartBB, SkipFirstBlock); 743 else 744 CacheInfo->first = BBSkipFirstBlockPair(); 745 746 SmallVector<BasicBlock*, 32> Worklist; 747 Worklist.push_back(StartBB); 748 749 // Keep track of the entries that we know are sorted. Previously cached 750 // entries will all be sorted. The entries we add we only sort on demand (we 751 // don't insert every element into its sorted position). We know that we 752 // won't get any reuse from currently inserted values, because we don't 753 // revisit blocks after we insert info for them. 754 unsigned NumSortedEntries = Cache->size(); 755 DEBUG(AssertSorted(*Cache)); 756 757 while (!Worklist.empty()) { 758 BasicBlock *BB = Worklist.pop_back_val(); 759 760 // Skip the first block if we have it. 761 if (!SkipFirstBlock) { 762 // Analyze the dependency of *Pointer in FromBB. See if we already have 763 // been here. 764 assert(Visited.count(BB) && "Should check 'visited' before adding to WL"); 765 766 // Get the dependency info for Pointer in BB. If we have cached 767 // information, we will use it, otherwise we compute it. 768 DEBUG(AssertSorted(*Cache, NumSortedEntries)); 769 MemDepResult Dep = GetNonLocalInfoForBlock(Pointer, PointeeSize, isLoad, 770 BB, Cache, NumSortedEntries); 771 772 // If we got a Def or Clobber, add this to the list of results. 773 if (!Dep.isNonLocal()) { 774 Result.push_back(NonLocalDepEntry(BB, Dep)); 775 continue; 776 } 777 } 778 779 // If 'Pointer' is an instruction defined in this block, then we need to do 780 // phi translation to change it into a value live in the predecessor block. 781 // If phi translation fails, then we can't continue dependence analysis. 782 Instruction *PtrInst = dyn_cast<Instruction>(Pointer); 783 bool NeedsPHITranslation = PtrInst && PtrInst->getParent() == BB; 784 785 // If no PHI translation is needed, just add all the predecessors of this 786 // block to scan them as well. 787 if (!NeedsPHITranslation) { 788 SkipFirstBlock = false; 789 for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) { 790 // Verify that we haven't looked at this block yet. 791 std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool> 792 InsertRes = Visited.insert(std::make_pair(*PI, Pointer)); 793 if (InsertRes.second) { 794 // First time we've looked at *PI. 795 Worklist.push_back(*PI); 796 continue; 797 } 798 799 // If we have seen this block before, but it was with a different 800 // pointer then we have a phi translation failure and we have to treat 801 // this as a clobber. 802 if (InsertRes.first->second != Pointer) 803 goto PredTranslationFailure; 804 } 805 continue; 806 } 807 808 // If we do need to do phi translation, then there are a bunch of different 809 // cases, because we have to find a Value* live in the predecessor block. We 810 // know that PtrInst is defined in this block at least. 811 812 // We may have added values to the cache list before this PHI translation. 813 // If so, we haven't done anything to ensure that the cache remains sorted. 814 // Sort it now (if needed) so that recursive invocations of 815 // getNonLocalPointerDepFromBB and other routines that could reuse the cache 816 // value will only see properly sorted cache arrays. 817 if (Cache && NumSortedEntries != Cache->size()) { 818 SortNonLocalDepInfoCache(*Cache, NumSortedEntries); 819 NumSortedEntries = Cache->size(); 820 } 821 822 // If this is directly a PHI node, just use the incoming values for each 823 // pred as the phi translated version. 824 if (PHINode *PtrPHI = dyn_cast<PHINode>(PtrInst)) { 825 Cache = 0; 826 827 for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) { 828 BasicBlock *Pred = *PI; 829 Value *PredPtr = PtrPHI->getIncomingValueForBlock(Pred); 830 831 // Check to see if we have already visited this pred block with another 832 // pointer. If so, we can't do this lookup. This failure can occur 833 // with PHI translation when a critical edge exists and the PHI node in 834 // the successor translates to a pointer value different than the 835 // pointer the block was first analyzed with. 836 std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool> 837 InsertRes = Visited.insert(std::make_pair(Pred, PredPtr)); 838 839 if (!InsertRes.second) { 840 // If the predecessor was visited with PredPtr, then we already did 841 // the analysis and can ignore it. 842 if (InsertRes.first->second == PredPtr) 843 continue; 844 845 // Otherwise, the block was previously analyzed with a different 846 // pointer. We can't represent the result of this case, so we just 847 // treat this as a phi translation failure. 848 goto PredTranslationFailure; 849 } 850 851 // FIXME: it is entirely possible that PHI translating will end up with 852 // the same value. Consider PHI translating something like: 853 // X = phi [x, bb1], [y, bb2]. PHI translating for bb1 doesn't *need* 854 // to recurse here, pedantically speaking. 855 856 // If we have a problem phi translating, fall through to the code below 857 // to handle the failure condition. 858 if (getNonLocalPointerDepFromBB(PredPtr, PointeeSize, isLoad, Pred, 859 Result, Visited)) 860 goto PredTranslationFailure; 861 } 862 863 // Refresh the CacheInfo/Cache pointer so that it isn't invalidated. 864 CacheInfo = &NonLocalPointerDeps[CacheKey]; 865 Cache = &CacheInfo->second; 866 NumSortedEntries = Cache->size(); 867 868 // Since we did phi translation, the "Cache" set won't contain all of the 869 // results for the query. This is ok (we can still use it to accelerate 870 // specific block queries) but we can't do the fastpath "return all 871 // results from the set" Clear out the indicator for this. 872 CacheInfo->first = BBSkipFirstBlockPair(); 873 SkipFirstBlock = false; 874 continue; 875 } 876 877 // TODO: BITCAST, GEP. 878 879 // cerr << "MEMDEP: Could not PHI translate: " << *Pointer; 880 // if (isa<BitCastInst>(PtrInst) || isa<GetElementPtrInst>(PtrInst)) 881 // cerr << "OP:\t\t\t\t" << *PtrInst->getOperand(0); 882 PredTranslationFailure: 883 884 if (Cache == 0) { 885 // Refresh the CacheInfo/Cache pointer if it got invalidated. 886 CacheInfo = &NonLocalPointerDeps[CacheKey]; 887 Cache = &CacheInfo->second; 888 NumSortedEntries = Cache->size(); 889 } 890 891 // Since we did phi translation, the "Cache" set won't contain all of the 892 // results for the query. This is ok (we can still use it to accelerate 893 // specific block queries) but we can't do the fastpath "return all 894 // results from the set" Clear out the indicator for this. 895 CacheInfo->first = BBSkipFirstBlockPair(); 896 897 // If *nothing* works, mark the pointer as being clobbered by the first 898 // instruction in this block. 899 // 900 // If this is the magic first block, return this as a clobber of the whole 901 // incoming value. Since we can't phi translate to one of the predecessors, 902 // we have to bail out. 903 if (SkipFirstBlock) 904 return true; 905 906 for (NonLocalDepInfo::reverse_iterator I = Cache->rbegin(); ; ++I) { 907 assert(I != Cache->rend() && "Didn't find current block??"); 908 if (I->first != BB) 909 continue; 910 911 assert(I->second.isNonLocal() && 912 "Should only be here with transparent block"); 913 I->second = MemDepResult::getClobber(BB->begin()); 914 ReverseNonLocalPtrDeps[BB->begin()].insert(CacheKey); 915 Result.push_back(*I); 916 break; 917 } 918 } 919 920 // Okay, we're done now. If we added new values to the cache, re-sort it. 921 SortNonLocalDepInfoCache(*Cache, NumSortedEntries); 922 DEBUG(AssertSorted(*Cache)); 923 return false; 924} 925 926/// RemoveCachedNonLocalPointerDependencies - If P exists in 927/// CachedNonLocalPointerInfo, remove it. 928void MemoryDependenceAnalysis:: 929RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P) { 930 CachedNonLocalPointerInfo::iterator It = 931 NonLocalPointerDeps.find(P); 932 if (It == NonLocalPointerDeps.end()) return; 933 934 // Remove all of the entries in the BB->val map. This involves removing 935 // instructions from the reverse map. 936 NonLocalDepInfo &PInfo = It->second.second; 937 938 for (unsigned i = 0, e = PInfo.size(); i != e; ++i) { 939 Instruction *Target = PInfo[i].second.getInst(); 940 if (Target == 0) continue; // Ignore non-local dep results. 941 assert(Target->getParent() == PInfo[i].first); 942 943 // Eliminating the dirty entry from 'Cache', so update the reverse info. 944 RemoveFromReverseMap(ReverseNonLocalPtrDeps, Target, P); 945 } 946 947 // Remove P from NonLocalPointerDeps (which deletes NonLocalDepInfo). 948 NonLocalPointerDeps.erase(It); 949} 950 951 952/// invalidateCachedPointerInfo - This method is used to invalidate cached 953/// information about the specified pointer, because it may be too 954/// conservative in memdep. This is an optional call that can be used when 955/// the client detects an equivalence between the pointer and some other 956/// value and replaces the other value with ptr. This can make Ptr available 957/// in more places that cached info does not necessarily keep. 958void MemoryDependenceAnalysis::invalidateCachedPointerInfo(Value *Ptr) { 959 // If Ptr isn't really a pointer, just ignore it. 960 if (!isa<PointerType>(Ptr->getType())) return; 961 // Flush store info for the pointer. 962 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, false)); 963 // Flush load info for the pointer. 964 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, true)); 965} 966 967/// removeInstruction - Remove an instruction from the dependence analysis, 968/// updating the dependence of instructions that previously depended on it. 969/// This method attempts to keep the cache coherent using the reverse map. 970void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) { 971 // Walk through the Non-local dependencies, removing this one as the value 972 // for any cached queries. 973 NonLocalDepMapType::iterator NLDI = NonLocalDeps.find(RemInst); 974 if (NLDI != NonLocalDeps.end()) { 975 NonLocalDepInfo &BlockMap = NLDI->second.first; 976 for (NonLocalDepInfo::iterator DI = BlockMap.begin(), DE = BlockMap.end(); 977 DI != DE; ++DI) 978 if (Instruction *Inst = DI->second.getInst()) 979 RemoveFromReverseMap(ReverseNonLocalDeps, Inst, RemInst); 980 NonLocalDeps.erase(NLDI); 981 } 982 983 // If we have a cached local dependence query for this instruction, remove it. 984 // 985 LocalDepMapType::iterator LocalDepEntry = LocalDeps.find(RemInst); 986 if (LocalDepEntry != LocalDeps.end()) { 987 // Remove us from DepInst's reverse set now that the local dep info is gone. 988 if (Instruction *Inst = LocalDepEntry->second.getInst()) 989 RemoveFromReverseMap(ReverseLocalDeps, Inst, RemInst); 990 991 // Remove this local dependency info. 992 LocalDeps.erase(LocalDepEntry); 993 } 994 995 // If we have any cached pointer dependencies on this instruction, remove 996 // them. If the instruction has non-pointer type, then it can't be a pointer 997 // base. 998 999 // Remove it from both the load info and the store info. The instruction 1000 // can't be in either of these maps if it is non-pointer. 1001 if (isa<PointerType>(RemInst->getType())) { 1002 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, false)); 1003 RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, true)); 1004 } 1005 1006 // Loop over all of the things that depend on the instruction we're removing. 1007 // 1008 SmallVector<std::pair<Instruction*, Instruction*>, 8> ReverseDepsToAdd; 1009 1010 // If we find RemInst as a clobber or Def in any of the maps for other values, 1011 // we need to replace its entry with a dirty version of the instruction after 1012 // it. If RemInst is a terminator, we use a null dirty value. 1013 // 1014 // Using a dirty version of the instruction after RemInst saves having to scan 1015 // the entire block to get to this point. 1016 MemDepResult NewDirtyVal; 1017 if (!RemInst->isTerminator()) 1018 NewDirtyVal = MemDepResult::getDirty(++BasicBlock::iterator(RemInst)); 1019 1020 ReverseDepMapType::iterator ReverseDepIt = ReverseLocalDeps.find(RemInst); 1021 if (ReverseDepIt != ReverseLocalDeps.end()) { 1022 SmallPtrSet<Instruction*, 4> &ReverseDeps = ReverseDepIt->second; 1023 // RemInst can't be the terminator if it has local stuff depending on it. 1024 assert(!ReverseDeps.empty() && !isa<TerminatorInst>(RemInst) && 1025 "Nothing can locally depend on a terminator"); 1026 1027 for (SmallPtrSet<Instruction*, 4>::iterator I = ReverseDeps.begin(), 1028 E = ReverseDeps.end(); I != E; ++I) { 1029 Instruction *InstDependingOnRemInst = *I; 1030 assert(InstDependingOnRemInst != RemInst && 1031 "Already removed our local dep info"); 1032 1033 LocalDeps[InstDependingOnRemInst] = NewDirtyVal; 1034 1035 // Make sure to remember that new things depend on NewDepInst. 1036 assert(NewDirtyVal.getInst() && "There is no way something else can have " 1037 "a local dep on this if it is a terminator!"); 1038 ReverseDepsToAdd.push_back(std::make_pair(NewDirtyVal.getInst(), 1039 InstDependingOnRemInst)); 1040 } 1041 1042 ReverseLocalDeps.erase(ReverseDepIt); 1043 1044 // Add new reverse deps after scanning the set, to avoid invalidating the 1045 // 'ReverseDeps' reference. 1046 while (!ReverseDepsToAdd.empty()) { 1047 ReverseLocalDeps[ReverseDepsToAdd.back().first] 1048 .insert(ReverseDepsToAdd.back().second); 1049 ReverseDepsToAdd.pop_back(); 1050 } 1051 } 1052 1053 ReverseDepIt = ReverseNonLocalDeps.find(RemInst); 1054 if (ReverseDepIt != ReverseNonLocalDeps.end()) { 1055 SmallPtrSet<Instruction*, 4> &Set = ReverseDepIt->second; 1056 for (SmallPtrSet<Instruction*, 4>::iterator I = Set.begin(), E = Set.end(); 1057 I != E; ++I) { 1058 assert(*I != RemInst && "Already removed NonLocalDep info for RemInst"); 1059 1060 PerInstNLInfo &INLD = NonLocalDeps[*I]; 1061 // The information is now dirty! 1062 INLD.second = true; 1063 1064 for (NonLocalDepInfo::iterator DI = INLD.first.begin(), 1065 DE = INLD.first.end(); DI != DE; ++DI) { 1066 if (DI->second.getInst() != RemInst) continue; 1067 1068 // Convert to a dirty entry for the subsequent instruction. 1069 DI->second = NewDirtyVal; 1070 1071 if (Instruction *NextI = NewDirtyVal.getInst()) 1072 ReverseDepsToAdd.push_back(std::make_pair(NextI, *I)); 1073 } 1074 } 1075 1076 ReverseNonLocalDeps.erase(ReverseDepIt); 1077 1078 // Add new reverse deps after scanning the set, to avoid invalidating 'Set' 1079 while (!ReverseDepsToAdd.empty()) { 1080 ReverseNonLocalDeps[ReverseDepsToAdd.back().first] 1081 .insert(ReverseDepsToAdd.back().second); 1082 ReverseDepsToAdd.pop_back(); 1083 } 1084 } 1085 1086 // If the instruction is in ReverseNonLocalPtrDeps then it appears as a 1087 // value in the NonLocalPointerDeps info. 1088 ReverseNonLocalPtrDepTy::iterator ReversePtrDepIt = 1089 ReverseNonLocalPtrDeps.find(RemInst); 1090 if (ReversePtrDepIt != ReverseNonLocalPtrDeps.end()) { 1091 SmallPtrSet<ValueIsLoadPair, 4> &Set = ReversePtrDepIt->second; 1092 SmallVector<std::pair<Instruction*, ValueIsLoadPair>,8> ReversePtrDepsToAdd; 1093 1094 for (SmallPtrSet<ValueIsLoadPair, 4>::iterator I = Set.begin(), 1095 E = Set.end(); I != E; ++I) { 1096 ValueIsLoadPair P = *I; 1097 assert(P.getPointer() != RemInst && 1098 "Already removed NonLocalPointerDeps info for RemInst"); 1099 1100 NonLocalDepInfo &NLPDI = NonLocalPointerDeps[P].second; 1101 1102 // The cache is not valid for any specific block anymore. 1103 NonLocalPointerDeps[P].first = BBSkipFirstBlockPair(); 1104 1105 // Update any entries for RemInst to use the instruction after it. 1106 for (NonLocalDepInfo::iterator DI = NLPDI.begin(), DE = NLPDI.end(); 1107 DI != DE; ++DI) { 1108 if (DI->second.getInst() != RemInst) continue; 1109 1110 // Convert to a dirty entry for the subsequent instruction. 1111 DI->second = NewDirtyVal; 1112 1113 if (Instruction *NewDirtyInst = NewDirtyVal.getInst()) 1114 ReversePtrDepsToAdd.push_back(std::make_pair(NewDirtyInst, P)); 1115 } 1116 1117 // Re-sort the NonLocalDepInfo. Changing the dirty entry to its 1118 // subsequent value may invalidate the sortedness. 1119 std::sort(NLPDI.begin(), NLPDI.end()); 1120 } 1121 1122 ReverseNonLocalPtrDeps.erase(ReversePtrDepIt); 1123 1124 while (!ReversePtrDepsToAdd.empty()) { 1125 ReverseNonLocalPtrDeps[ReversePtrDepsToAdd.back().first] 1126 .insert(ReversePtrDepsToAdd.back().second); 1127 ReversePtrDepsToAdd.pop_back(); 1128 } 1129 } 1130 1131 1132 assert(!NonLocalDeps.count(RemInst) && "RemInst got reinserted?"); 1133 AA->deleteValue(RemInst); 1134 DEBUG(verifyRemoved(RemInst)); 1135} 1136/// verifyRemoved - Verify that the specified instruction does not occur 1137/// in our internal data structures. 1138void MemoryDependenceAnalysis::verifyRemoved(Instruction *D) const { 1139 for (LocalDepMapType::const_iterator I = LocalDeps.begin(), 1140 E = LocalDeps.end(); I != E; ++I) { 1141 assert(I->first != D && "Inst occurs in data structures"); 1142 assert(I->second.getInst() != D && 1143 "Inst occurs in data structures"); 1144 } 1145 1146 for (CachedNonLocalPointerInfo::const_iterator I =NonLocalPointerDeps.begin(), 1147 E = NonLocalPointerDeps.end(); I != E; ++I) { 1148 assert(I->first.getPointer() != D && "Inst occurs in NLPD map key"); 1149 const NonLocalDepInfo &Val = I->second.second; 1150 for (NonLocalDepInfo::const_iterator II = Val.begin(), E = Val.end(); 1151 II != E; ++II) 1152 assert(II->second.getInst() != D && "Inst occurs as NLPD value"); 1153 } 1154 1155 for (NonLocalDepMapType::const_iterator I = NonLocalDeps.begin(), 1156 E = NonLocalDeps.end(); I != E; ++I) { 1157 assert(I->first != D && "Inst occurs in data structures"); 1158 const PerInstNLInfo &INLD = I->second; 1159 for (NonLocalDepInfo::const_iterator II = INLD.first.begin(), 1160 EE = INLD.first.end(); II != EE; ++II) 1161 assert(II->second.getInst() != D && "Inst occurs in data structures"); 1162 } 1163 1164 for (ReverseDepMapType::const_iterator I = ReverseLocalDeps.begin(), 1165 E = ReverseLocalDeps.end(); I != E; ++I) { 1166 assert(I->first != D && "Inst occurs in data structures"); 1167 for (SmallPtrSet<Instruction*, 4>::const_iterator II = I->second.begin(), 1168 EE = I->second.end(); II != EE; ++II) 1169 assert(*II != D && "Inst occurs in data structures"); 1170 } 1171 1172 for (ReverseDepMapType::const_iterator I = ReverseNonLocalDeps.begin(), 1173 E = ReverseNonLocalDeps.end(); 1174 I != E; ++I) { 1175 assert(I->first != D && "Inst occurs in data structures"); 1176 for (SmallPtrSet<Instruction*, 4>::const_iterator II = I->second.begin(), 1177 EE = I->second.end(); II != EE; ++II) 1178 assert(*II != D && "Inst occurs in data structures"); 1179 } 1180 1181 for (ReverseNonLocalPtrDepTy::const_iterator 1182 I = ReverseNonLocalPtrDeps.begin(), 1183 E = ReverseNonLocalPtrDeps.end(); I != E; ++I) { 1184 assert(I->first != D && "Inst occurs in rev NLPD map"); 1185 1186 for (SmallPtrSet<ValueIsLoadPair, 4>::const_iterator II = I->second.begin(), 1187 E = I->second.end(); II != E; ++II) 1188 assert(*II != ValueIsLoadPair(D, false) && 1189 *II != ValueIsLoadPair(D, true) && 1190 "Inst occurs in ReverseNonLocalPtrDeps map"); 1191 } 1192 1193} 1194