GlobalsModRef.cpp revision 202878
1//===- GlobalsModRef.cpp - Simple Mod/Ref Analysis for Globals ------------===// 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 simple pass provides alias and mod/ref information for global values 11// that do not have their address taken, and keeps track of whether functions 12// read or write memory (are "pure"). For this simple (but very common) case, 13// we can provide pretty accurate and useful information. 14// 15//===----------------------------------------------------------------------===// 16 17#define DEBUG_TYPE "globalsmodref-aa" 18#include "llvm/Analysis/Passes.h" 19#include "llvm/Module.h" 20#include "llvm/Pass.h" 21#include "llvm/Instructions.h" 22#include "llvm/Constants.h" 23#include "llvm/DerivedTypes.h" 24#include "llvm/Analysis/AliasAnalysis.h" 25#include "llvm/Analysis/CallGraph.h" 26#include "llvm/Analysis/MemoryBuiltins.h" 27#include "llvm/Support/CommandLine.h" 28#include "llvm/Support/InstIterator.h" 29#include "llvm/ADT/Statistic.h" 30#include "llvm/ADT/SCCIterator.h" 31#include <set> 32using namespace llvm; 33 34STATISTIC(NumNonAddrTakenGlobalVars, 35 "Number of global vars without address taken"); 36STATISTIC(NumNonAddrTakenFunctions,"Number of functions without address taken"); 37STATISTIC(NumNoMemFunctions, "Number of functions that do not access memory"); 38STATISTIC(NumReadMemFunctions, "Number of functions that only read memory"); 39STATISTIC(NumIndirectGlobalVars, "Number of indirect global objects"); 40 41namespace { 42 /// FunctionRecord - One instance of this structure is stored for every 43 /// function in the program. Later, the entries for these functions are 44 /// removed if the function is found to call an external function (in which 45 /// case we know nothing about it. 46 struct FunctionRecord { 47 /// GlobalInfo - Maintain mod/ref info for all of the globals without 48 /// addresses taken that are read or written (transitively) by this 49 /// function. 50 std::map<GlobalValue*, unsigned> GlobalInfo; 51 52 /// MayReadAnyGlobal - May read global variables, but it is not known which. 53 bool MayReadAnyGlobal; 54 55 unsigned getInfoForGlobal(GlobalValue *GV) const { 56 unsigned Effect = MayReadAnyGlobal ? AliasAnalysis::Ref : 0; 57 std::map<GlobalValue*, unsigned>::const_iterator I = GlobalInfo.find(GV); 58 if (I != GlobalInfo.end()) 59 Effect |= I->second; 60 return Effect; 61 } 62 63 /// FunctionEffect - Capture whether or not this function reads or writes to 64 /// ANY memory. If not, we can do a lot of aggressive analysis on it. 65 unsigned FunctionEffect; 66 67 FunctionRecord() : MayReadAnyGlobal (false), FunctionEffect(0) {} 68 }; 69 70 /// GlobalsModRef - The actual analysis pass. 71 class GlobalsModRef : public ModulePass, public AliasAnalysis { 72 /// NonAddressTakenGlobals - The globals that do not have their addresses 73 /// taken. 74 std::set<GlobalValue*> NonAddressTakenGlobals; 75 76 /// IndirectGlobals - The memory pointed to by this global is known to be 77 /// 'owned' by the global. 78 std::set<GlobalValue*> IndirectGlobals; 79 80 /// AllocsForIndirectGlobals - If an instruction allocates memory for an 81 /// indirect global, this map indicates which one. 82 std::map<Value*, GlobalValue*> AllocsForIndirectGlobals; 83 84 /// FunctionInfo - For each function, keep track of what globals are 85 /// modified or read. 86 std::map<Function*, FunctionRecord> FunctionInfo; 87 88 public: 89 static char ID; 90 GlobalsModRef() : ModulePass(&ID) {} 91 92 bool runOnModule(Module &M) { 93 InitializeAliasAnalysis(this); // set up super class 94 AnalyzeGlobals(M); // find non-addr taken globals 95 AnalyzeCallGraph(getAnalysis<CallGraph>(), M); // Propagate on CG 96 return false; 97 } 98 99 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 100 AliasAnalysis::getAnalysisUsage(AU); 101 AU.addRequired<CallGraph>(); 102 AU.setPreservesAll(); // Does not transform code 103 } 104 105 //------------------------------------------------ 106 // Implement the AliasAnalysis API 107 // 108 AliasResult alias(const Value *V1, unsigned V1Size, 109 const Value *V2, unsigned V2Size); 110 ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size); 111 ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) { 112 return AliasAnalysis::getModRefInfo(CS1,CS2); 113 } 114 115 /// getModRefBehavior - Return the behavior of the specified function if 116 /// called from the specified call site. The call site may be null in which 117 /// case the most generic behavior of this function should be returned. 118 ModRefBehavior getModRefBehavior(Function *F, 119 std::vector<PointerAccessInfo> *Info) { 120 if (FunctionRecord *FR = getFunctionInfo(F)) { 121 if (FR->FunctionEffect == 0) 122 return DoesNotAccessMemory; 123 else if ((FR->FunctionEffect & Mod) == 0) 124 return OnlyReadsMemory; 125 } 126 return AliasAnalysis::getModRefBehavior(F, Info); 127 } 128 129 /// getModRefBehavior - Return the behavior of the specified function if 130 /// called from the specified call site. The call site may be null in which 131 /// case the most generic behavior of this function should be returned. 132 ModRefBehavior getModRefBehavior(CallSite CS, 133 std::vector<PointerAccessInfo> *Info) { 134 Function* F = CS.getCalledFunction(); 135 if (!F) return AliasAnalysis::getModRefBehavior(CS, Info); 136 if (FunctionRecord *FR = getFunctionInfo(F)) { 137 if (FR->FunctionEffect == 0) 138 return DoesNotAccessMemory; 139 else if ((FR->FunctionEffect & Mod) == 0) 140 return OnlyReadsMemory; 141 } 142 return AliasAnalysis::getModRefBehavior(CS, Info); 143 } 144 145 virtual void deleteValue(Value *V); 146 virtual void copyValue(Value *From, Value *To); 147 148 /// getAdjustedAnalysisPointer - This method is used when a pass implements 149 /// an analysis interface through multiple inheritance. If needed, it 150 /// should override this to adjust the this pointer as needed for the 151 /// specified pass info. 152 virtual void *getAdjustedAnalysisPointer(const PassInfo *PI) { 153 if (PI->isPassID(&AliasAnalysis::ID)) 154 return (AliasAnalysis*)this; 155 return this; 156 } 157 158 private: 159 /// getFunctionInfo - Return the function info for the function, or null if 160 /// we don't have anything useful to say about it. 161 FunctionRecord *getFunctionInfo(Function *F) { 162 std::map<Function*, FunctionRecord>::iterator I = FunctionInfo.find(F); 163 if (I != FunctionInfo.end()) 164 return &I->second; 165 return 0; 166 } 167 168 void AnalyzeGlobals(Module &M); 169 void AnalyzeCallGraph(CallGraph &CG, Module &M); 170 bool AnalyzeUsesOfPointer(Value *V, std::vector<Function*> &Readers, 171 std::vector<Function*> &Writers, 172 GlobalValue *OkayStoreDest = 0); 173 bool AnalyzeIndirectGlobalMemory(GlobalValue *GV); 174 }; 175} 176 177char GlobalsModRef::ID = 0; 178static RegisterPass<GlobalsModRef> 179X("globalsmodref-aa", "Simple mod/ref analysis for globals", false, true); 180static RegisterAnalysisGroup<AliasAnalysis> Y(X); 181 182Pass *llvm::createGlobalsModRefPass() { return new GlobalsModRef(); } 183 184/// AnalyzeGlobals - Scan through the users of all of the internal 185/// GlobalValue's in the program. If none of them have their "address taken" 186/// (really, their address passed to something nontrivial), record this fact, 187/// and record the functions that they are used directly in. 188void GlobalsModRef::AnalyzeGlobals(Module &M) { 189 std::vector<Function*> Readers, Writers; 190 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) 191 if (I->hasLocalLinkage()) { 192 if (!AnalyzeUsesOfPointer(I, Readers, Writers)) { 193 // Remember that we are tracking this global. 194 NonAddressTakenGlobals.insert(I); 195 ++NumNonAddrTakenFunctions; 196 } 197 Readers.clear(); Writers.clear(); 198 } 199 200 for (Module::global_iterator I = M.global_begin(), E = M.global_end(); 201 I != E; ++I) 202 if (I->hasLocalLinkage()) { 203 if (!AnalyzeUsesOfPointer(I, Readers, Writers)) { 204 // Remember that we are tracking this global, and the mod/ref fns 205 NonAddressTakenGlobals.insert(I); 206 207 for (unsigned i = 0, e = Readers.size(); i != e; ++i) 208 FunctionInfo[Readers[i]].GlobalInfo[I] |= Ref; 209 210 if (!I->isConstant()) // No need to keep track of writers to constants 211 for (unsigned i = 0, e = Writers.size(); i != e; ++i) 212 FunctionInfo[Writers[i]].GlobalInfo[I] |= Mod; 213 ++NumNonAddrTakenGlobalVars; 214 215 // If this global holds a pointer type, see if it is an indirect global. 216 if (isa<PointerType>(I->getType()->getElementType()) && 217 AnalyzeIndirectGlobalMemory(I)) 218 ++NumIndirectGlobalVars; 219 } 220 Readers.clear(); Writers.clear(); 221 } 222} 223 224/// AnalyzeUsesOfPointer - Look at all of the users of the specified pointer. 225/// If this is used by anything complex (i.e., the address escapes), return 226/// true. Also, while we are at it, keep track of those functions that read and 227/// write to the value. 228/// 229/// If OkayStoreDest is non-null, stores into this global are allowed. 230bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V, 231 std::vector<Function*> &Readers, 232 std::vector<Function*> &Writers, 233 GlobalValue *OkayStoreDest) { 234 if (!isa<PointerType>(V->getType())) return true; 235 236 for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI) 237 if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 238 Readers.push_back(LI->getParent()->getParent()); 239 } else if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) { 240 if (V == SI->getOperand(1)) { 241 Writers.push_back(SI->getParent()->getParent()); 242 } else if (SI->getOperand(1) != OkayStoreDest) { 243 return true; // Storing the pointer 244 } 245 } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) { 246 if (AnalyzeUsesOfPointer(GEP, Readers, Writers)) return true; 247 } else if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI)) { 248 if (AnalyzeUsesOfPointer(BCI, Readers, Writers, OkayStoreDest)) 249 return true; 250 } else if (isFreeCall(*UI)) { 251 Writers.push_back(cast<Instruction>(*UI)->getParent()->getParent()); 252 } else if (CallInst *CI = dyn_cast<CallInst>(*UI)) { 253 // Make sure that this is just the function being called, not that it is 254 // passing into the function. 255 for (unsigned i = 1, e = CI->getNumOperands(); i != e; ++i) 256 if (CI->getOperand(i) == V) return true; 257 } else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) { 258 // Make sure that this is just the function being called, not that it is 259 // passing into the function. 260 for (unsigned i = 3, e = II->getNumOperands(); i != e; ++i) 261 if (II->getOperand(i) == V) return true; 262 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(*UI)) { 263 if (CE->getOpcode() == Instruction::GetElementPtr || 264 CE->getOpcode() == Instruction::BitCast) { 265 if (AnalyzeUsesOfPointer(CE, Readers, Writers)) 266 return true; 267 } else { 268 return true; 269 } 270 } else if (ICmpInst *ICI = dyn_cast<ICmpInst>(*UI)) { 271 if (!isa<ConstantPointerNull>(ICI->getOperand(1))) 272 return true; // Allow comparison against null. 273 } else { 274 return true; 275 } 276 return false; 277} 278 279/// AnalyzeIndirectGlobalMemory - We found an non-address-taken global variable 280/// which holds a pointer type. See if the global always points to non-aliased 281/// heap memory: that is, all initializers of the globals are allocations, and 282/// those allocations have no use other than initialization of the global. 283/// Further, all loads out of GV must directly use the memory, not store the 284/// pointer somewhere. If this is true, we consider the memory pointed to by 285/// GV to be owned by GV and can disambiguate other pointers from it. 286bool GlobalsModRef::AnalyzeIndirectGlobalMemory(GlobalValue *GV) { 287 // Keep track of values related to the allocation of the memory, f.e. the 288 // value produced by the malloc call and any casts. 289 std::vector<Value*> AllocRelatedValues; 290 291 // Walk the user list of the global. If we find anything other than a direct 292 // load or store, bail out. 293 for (Value::use_iterator I = GV->use_begin(), E = GV->use_end(); I != E; ++I){ 294 if (LoadInst *LI = dyn_cast<LoadInst>(*I)) { 295 // The pointer loaded from the global can only be used in simple ways: 296 // we allow addressing of it and loading storing to it. We do *not* allow 297 // storing the loaded pointer somewhere else or passing to a function. 298 std::vector<Function*> ReadersWriters; 299 if (AnalyzeUsesOfPointer(LI, ReadersWriters, ReadersWriters)) 300 return false; // Loaded pointer escapes. 301 // TODO: Could try some IP mod/ref of the loaded pointer. 302 } else if (StoreInst *SI = dyn_cast<StoreInst>(*I)) { 303 // Storing the global itself. 304 if (SI->getOperand(0) == GV) return false; 305 306 // If storing the null pointer, ignore it. 307 if (isa<ConstantPointerNull>(SI->getOperand(0))) 308 continue; 309 310 // Check the value being stored. 311 Value *Ptr = SI->getOperand(0)->getUnderlyingObject(); 312 313 if (isMalloc(Ptr)) { 314 // Okay, easy case. 315 } else if (CallInst *CI = dyn_cast<CallInst>(Ptr)) { 316 Function *F = CI->getCalledFunction(); 317 if (!F || !F->isDeclaration()) return false; // Too hard to analyze. 318 if (F->getName() != "calloc") return false; // Not calloc. 319 } else { 320 return false; // Too hard to analyze. 321 } 322 323 // Analyze all uses of the allocation. If any of them are used in a 324 // non-simple way (e.g. stored to another global) bail out. 325 std::vector<Function*> ReadersWriters; 326 if (AnalyzeUsesOfPointer(Ptr, ReadersWriters, ReadersWriters, GV)) 327 return false; // Loaded pointer escapes. 328 329 // Remember that this allocation is related to the indirect global. 330 AllocRelatedValues.push_back(Ptr); 331 } else { 332 // Something complex, bail out. 333 return false; 334 } 335 } 336 337 // Okay, this is an indirect global. Remember all of the allocations for 338 // this global in AllocsForIndirectGlobals. 339 while (!AllocRelatedValues.empty()) { 340 AllocsForIndirectGlobals[AllocRelatedValues.back()] = GV; 341 AllocRelatedValues.pop_back(); 342 } 343 IndirectGlobals.insert(GV); 344 return true; 345} 346 347/// AnalyzeCallGraph - At this point, we know the functions where globals are 348/// immediately stored to and read from. Propagate this information up the call 349/// graph to all callers and compute the mod/ref info for all memory for each 350/// function. 351void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) { 352 // We do a bottom-up SCC traversal of the call graph. In other words, we 353 // visit all callees before callers (leaf-first). 354 for (scc_iterator<CallGraph*> I = scc_begin(&CG), E = scc_end(&CG); I != E; 355 ++I) { 356 std::vector<CallGraphNode *> &SCC = *I; 357 assert(!SCC.empty() && "SCC with no functions?"); 358 359 if (!SCC[0]->getFunction()) { 360 // Calls externally - can't say anything useful. Remove any existing 361 // function records (may have been created when scanning globals). 362 for (unsigned i = 0, e = SCC.size(); i != e; ++i) 363 FunctionInfo.erase(SCC[i]->getFunction()); 364 continue; 365 } 366 367 FunctionRecord &FR = FunctionInfo[SCC[0]->getFunction()]; 368 369 bool KnowNothing = false; 370 unsigned FunctionEffect = 0; 371 372 // Collect the mod/ref properties due to called functions. We only compute 373 // one mod-ref set. 374 for (unsigned i = 0, e = SCC.size(); i != e && !KnowNothing; ++i) { 375 Function *F = SCC[i]->getFunction(); 376 if (!F) { 377 KnowNothing = true; 378 break; 379 } 380 381 if (F->isDeclaration()) { 382 // Try to get mod/ref behaviour from function attributes. 383 if (F->doesNotAccessMemory()) { 384 // Can't do better than that! 385 } else if (F->onlyReadsMemory()) { 386 FunctionEffect |= Ref; 387 if (!F->isIntrinsic()) 388 // This function might call back into the module and read a global - 389 // consider every global as possibly being read by this function. 390 FR.MayReadAnyGlobal = true; 391 } else { 392 FunctionEffect |= ModRef; 393 // Can't say anything useful unless it's an intrinsic - they don't 394 // read or write global variables of the kind considered here. 395 KnowNothing = !F->isIntrinsic(); 396 } 397 continue; 398 } 399 400 for (CallGraphNode::iterator CI = SCC[i]->begin(), E = SCC[i]->end(); 401 CI != E && !KnowNothing; ++CI) 402 if (Function *Callee = CI->second->getFunction()) { 403 if (FunctionRecord *CalleeFR = getFunctionInfo(Callee)) { 404 // Propagate function effect up. 405 FunctionEffect |= CalleeFR->FunctionEffect; 406 407 // Incorporate callee's effects on globals into our info. 408 for (std::map<GlobalValue*, unsigned>::iterator GI = 409 CalleeFR->GlobalInfo.begin(), E = CalleeFR->GlobalInfo.end(); 410 GI != E; ++GI) 411 FR.GlobalInfo[GI->first] |= GI->second; 412 FR.MayReadAnyGlobal |= CalleeFR->MayReadAnyGlobal; 413 } else { 414 // Can't say anything about it. However, if it is inside our SCC, 415 // then nothing needs to be done. 416 CallGraphNode *CalleeNode = CG[Callee]; 417 if (std::find(SCC.begin(), SCC.end(), CalleeNode) == SCC.end()) 418 KnowNothing = true; 419 } 420 } else { 421 KnowNothing = true; 422 } 423 } 424 425 // If we can't say anything useful about this SCC, remove all SCC functions 426 // from the FunctionInfo map. 427 if (KnowNothing) { 428 for (unsigned i = 0, e = SCC.size(); i != e; ++i) 429 FunctionInfo.erase(SCC[i]->getFunction()); 430 continue; 431 } 432 433 // Scan the function bodies for explicit loads or stores. 434 for (unsigned i = 0, e = SCC.size(); i != e && FunctionEffect != ModRef;++i) 435 for (inst_iterator II = inst_begin(SCC[i]->getFunction()), 436 E = inst_end(SCC[i]->getFunction()); 437 II != E && FunctionEffect != ModRef; ++II) 438 if (isa<LoadInst>(*II)) { 439 FunctionEffect |= Ref; 440 if (cast<LoadInst>(*II).isVolatile()) 441 // Volatile loads may have side-effects, so mark them as writing 442 // memory (for example, a flag inside the processor). 443 FunctionEffect |= Mod; 444 } else if (isa<StoreInst>(*II)) { 445 FunctionEffect |= Mod; 446 if (cast<StoreInst>(*II).isVolatile()) 447 // Treat volatile stores as reading memory somewhere. 448 FunctionEffect |= Ref; 449 } else if (isMalloc(&cast<Instruction>(*II)) || 450 isFreeCall(&cast<Instruction>(*II))) { 451 FunctionEffect |= ModRef; 452 } 453 454 if ((FunctionEffect & Mod) == 0) 455 ++NumReadMemFunctions; 456 if (FunctionEffect == 0) 457 ++NumNoMemFunctions; 458 FR.FunctionEffect = FunctionEffect; 459 460 // Finally, now that we know the full effect on this SCC, clone the 461 // information to each function in the SCC. 462 for (unsigned i = 1, e = SCC.size(); i != e; ++i) 463 FunctionInfo[SCC[i]->getFunction()] = FR; 464 } 465} 466 467 468 469/// alias - If one of the pointers is to a global that we are tracking, and the 470/// other is some random pointer, we know there cannot be an alias, because the 471/// address of the global isn't taken. 472AliasAnalysis::AliasResult 473GlobalsModRef::alias(const Value *V1, unsigned V1Size, 474 const Value *V2, unsigned V2Size) { 475 // Get the base object these pointers point to. 476 Value *UV1 = const_cast<Value*>(V1->getUnderlyingObject()); 477 Value *UV2 = const_cast<Value*>(V2->getUnderlyingObject()); 478 479 // If either of the underlying values is a global, they may be non-addr-taken 480 // globals, which we can answer queries about. 481 GlobalValue *GV1 = dyn_cast<GlobalValue>(UV1); 482 GlobalValue *GV2 = dyn_cast<GlobalValue>(UV2); 483 if (GV1 || GV2) { 484 // If the global's address is taken, pretend we don't know it's a pointer to 485 // the global. 486 if (GV1 && !NonAddressTakenGlobals.count(GV1)) GV1 = 0; 487 if (GV2 && !NonAddressTakenGlobals.count(GV2)) GV2 = 0; 488 489 // If the the two pointers are derived from two different non-addr-taken 490 // globals, or if one is and the other isn't, we know these can't alias. 491 if ((GV1 || GV2) && GV1 != GV2) 492 return NoAlias; 493 494 // Otherwise if they are both derived from the same addr-taken global, we 495 // can't know the two accesses don't overlap. 496 } 497 498 // These pointers may be based on the memory owned by an indirect global. If 499 // so, we may be able to handle this. First check to see if the base pointer 500 // is a direct load from an indirect global. 501 GV1 = GV2 = 0; 502 if (LoadInst *LI = dyn_cast<LoadInst>(UV1)) 503 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(LI->getOperand(0))) 504 if (IndirectGlobals.count(GV)) 505 GV1 = GV; 506 if (LoadInst *LI = dyn_cast<LoadInst>(UV2)) 507 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(LI->getOperand(0))) 508 if (IndirectGlobals.count(GV)) 509 GV2 = GV; 510 511 // These pointers may also be from an allocation for the indirect global. If 512 // so, also handle them. 513 if (AllocsForIndirectGlobals.count(UV1)) 514 GV1 = AllocsForIndirectGlobals[UV1]; 515 if (AllocsForIndirectGlobals.count(UV2)) 516 GV2 = AllocsForIndirectGlobals[UV2]; 517 518 // Now that we know whether the two pointers are related to indirect globals, 519 // use this to disambiguate the pointers. If either pointer is based on an 520 // indirect global and if they are not both based on the same indirect global, 521 // they cannot alias. 522 if ((GV1 || GV2) && GV1 != GV2) 523 return NoAlias; 524 525 return AliasAnalysis::alias(V1, V1Size, V2, V2Size); 526} 527 528AliasAnalysis::ModRefResult 529GlobalsModRef::getModRefInfo(CallSite CS, Value *P, unsigned Size) { 530 unsigned Known = ModRef; 531 532 // If we are asking for mod/ref info of a direct call with a pointer to a 533 // global we are tracking, return information if we have it. 534 if (GlobalValue *GV = dyn_cast<GlobalValue>(P->getUnderlyingObject())) 535 if (GV->hasLocalLinkage()) 536 if (Function *F = CS.getCalledFunction()) 537 if (NonAddressTakenGlobals.count(GV)) 538 if (FunctionRecord *FR = getFunctionInfo(F)) 539 Known = FR->getInfoForGlobal(GV); 540 541 if (Known == NoModRef) 542 return NoModRef; // No need to query other mod/ref analyses 543 return ModRefResult(Known & AliasAnalysis::getModRefInfo(CS, P, Size)); 544} 545 546 547//===----------------------------------------------------------------------===// 548// Methods to update the analysis as a result of the client transformation. 549// 550void GlobalsModRef::deleteValue(Value *V) { 551 if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) { 552 if (NonAddressTakenGlobals.erase(GV)) { 553 // This global might be an indirect global. If so, remove it and remove 554 // any AllocRelatedValues for it. 555 if (IndirectGlobals.erase(GV)) { 556 // Remove any entries in AllocsForIndirectGlobals for this global. 557 for (std::map<Value*, GlobalValue*>::iterator 558 I = AllocsForIndirectGlobals.begin(), 559 E = AllocsForIndirectGlobals.end(); I != E; ) { 560 if (I->second == GV) { 561 AllocsForIndirectGlobals.erase(I++); 562 } else { 563 ++I; 564 } 565 } 566 } 567 } 568 } 569 570 // Otherwise, if this is an allocation related to an indirect global, remove 571 // it. 572 AllocsForIndirectGlobals.erase(V); 573 574 AliasAnalysis::deleteValue(V); 575} 576 577void GlobalsModRef::copyValue(Value *From, Value *To) { 578 AliasAnalysis::copyValue(From, To); 579} 580