GlobalsModRef.cpp revision 1abe60b9be1b7b33e1fa422add5296d392831850
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/Support/Compiler.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 VISIBILITY_HIDDEN 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 unsigned getInfoForGlobal(GlobalValue *GV) const { 53 std::map<GlobalValue*, unsigned>::const_iterator I = GlobalInfo.find(GV); 54 if (I != GlobalInfo.end()) 55 return I->second; 56 return 0; 57 } 58 59 /// FunctionEffect - Capture whether or not this function reads or writes to 60 /// ANY memory. If not, we can do a lot of aggressive analysis on it. 61 unsigned FunctionEffect; 62 63 FunctionRecord() : FunctionEffect(0) {} 64 }; 65 66 /// GlobalsModRef - The actual analysis pass. 67 class VISIBILITY_HIDDEN GlobalsModRef 68 : public ModulePass, public AliasAnalysis { 69 /// NonAddressTakenGlobals - The globals that do not have their addresses 70 /// taken. 71 std::set<GlobalValue*> NonAddressTakenGlobals; 72 73 /// ReadGlobals - The globals without addresses taken that are read by 74 /// some function. 75 std::set<GlobalValue*> ReadGlobals; 76 77 /// IndirectGlobals - The memory pointed to by this global is known to be 78 /// 'owned' by the global. 79 std::set<GlobalValue*> IndirectGlobals; 80 81 /// AllocsForIndirectGlobals - If an instruction allocates memory for an 82 /// indirect global, this map indicates which one. 83 std::map<Value*, GlobalValue*> AllocsForIndirectGlobals; 84 85 /// FunctionInfo - For each function, keep track of what globals are 86 /// modified or read. 87 std::map<Function*, FunctionRecord> FunctionInfo; 88 89 public: 90 static char ID; 91 GlobalsModRef() : ModulePass(&ID) {} 92 93 bool runOnModule(Module &M) { 94 InitializeAliasAnalysis(this); // set up super class 95 AnalyzeGlobals(M); // find non-addr taken globals 96 AnalyzeCallGraph(getAnalysis<CallGraph>(), M); // Propagate on CG 97 return false; 98 } 99 100 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 101 AliasAnalysis::getAnalysisUsage(AU); 102 AU.addRequired<CallGraph>(); 103 AU.setPreservesAll(); // Does not transform code 104 } 105 106 //------------------------------------------------ 107 // Implement the AliasAnalysis API 108 // 109 AliasResult alias(const Value *V1, unsigned V1Size, 110 const Value *V2, unsigned V2Size); 111 ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size); 112 ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) { 113 return AliasAnalysis::getModRefInfo(CS1,CS2); 114 } 115 bool hasNoModRefInfoForCalls() const { return false; } 116 117 /// getModRefBehavior - Return the behavior of the specified function if 118 /// called from the specified call site. The call site may be null in which 119 /// case the most generic behavior of this function should be returned. 120 virtual ModRefBehavior getModRefBehavior(Function *F, CallSite CS, 121 std::vector<PointerAccessInfo> *Info) { 122 if (FunctionRecord *FR = getFunctionInfo(F)) { 123 if (FR->FunctionEffect == 0) 124 return DoesNotAccessMemory; 125 else if ((FR->FunctionEffect & Mod) == 0) 126 return OnlyReadsMemory; 127 } 128 return AliasAnalysis::getModRefBehavior(F, CS, Info); 129 } 130 131 virtual void deleteValue(Value *V); 132 virtual void copyValue(Value *From, Value *To); 133 134 private: 135 /// getFunctionInfo - Return the function info for the function, or null if 136 /// we don't have anything useful to say about it. 137 FunctionRecord *getFunctionInfo(Function *F) { 138 std::map<Function*, FunctionRecord>::iterator I = FunctionInfo.find(F); 139 if (I != FunctionInfo.end()) 140 return &I->second; 141 return 0; 142 } 143 144 void AnalyzeGlobals(Module &M); 145 void AnalyzeCallGraph(CallGraph &CG, Module &M); 146 bool AnalyzeUsesOfPointer(Value *V, std::vector<Function*> &Readers, 147 std::vector<Function*> &Writers, 148 GlobalValue *OkayStoreDest = 0); 149 bool AnalyzeIndirectGlobalMemory(GlobalValue *GV); 150 }; 151} 152 153char GlobalsModRef::ID = 0; 154static RegisterPass<GlobalsModRef> 155X("globalsmodref-aa", "Simple mod/ref analysis for globals", false, true); 156static RegisterAnalysisGroup<AliasAnalysis> Y(X); 157 158Pass *llvm::createGlobalsModRefPass() { return new GlobalsModRef(); } 159 160/// getUnderlyingObject - This traverses the use chain to figure out what object 161/// the specified value points to. If the value points to, or is derived from, 162/// a global object, return it. 163static Value *getUnderlyingObject(Value *V) { 164 if (!isa<PointerType>(V->getType())) return V; 165 166 // If we are at some type of object... return it. 167 if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) return GV; 168 169 // Traverse through different addressing mechanisms. 170 if (Instruction *I = dyn_cast<Instruction>(V)) { 171 if (isa<BitCastInst>(I) || isa<GetElementPtrInst>(I)) 172 return getUnderlyingObject(I->getOperand(0)); 173 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) { 174 if (CE->getOpcode() == Instruction::BitCast || 175 CE->getOpcode() == Instruction::GetElementPtr) 176 return getUnderlyingObject(CE->getOperand(0)); 177 } 178 179 // Otherwise, we don't know what this is, return it as the base pointer. 180 return V; 181} 182 183/// AnalyzeGlobals - Scan through the users of all of the internal 184/// GlobalValue's in the program. If none of them have their "address taken" 185/// (really, their address passed to something nontrivial), record this fact, 186/// and record the functions that they are used directly in. 187void GlobalsModRef::AnalyzeGlobals(Module &M) { 188 std::vector<Function*> Readers, Writers; 189 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) 190 if (I->hasInternalLinkage()) { 191 if (!AnalyzeUsesOfPointer(I, Readers, Writers)) { 192 // Remember that we are tracking this global. 193 NonAddressTakenGlobals.insert(I); 194 ++NumNonAddrTakenFunctions; 195 } 196 Readers.clear(); Writers.clear(); 197 } 198 199 for (Module::global_iterator I = M.global_begin(), E = M.global_end(); 200 I != E; ++I) 201 if (I->hasInternalLinkage()) { 202 if (!AnalyzeUsesOfPointer(I, Readers, Writers)) { 203 // Remember that we are tracking this global, and the mod/ref fns 204 NonAddressTakenGlobals.insert(I); 205 206 if (!Readers.empty()) 207 // Some function read this global - remember that. 208 ReadGlobals.insert(I); 209 210 for (unsigned i = 0, e = Readers.size(); i != e; ++i) 211 FunctionInfo[Readers[i]].GlobalInfo[I] |= Ref; 212 213 if (!I->isConstant()) // No need to keep track of writers to constants 214 for (unsigned i = 0, e = Writers.size(); i != e; ++i) 215 FunctionInfo[Writers[i]].GlobalInfo[I] |= Mod; 216 ++NumNonAddrTakenGlobalVars; 217 218 // If this global holds a pointer type, see if it is an indirect global. 219 if (isa<PointerType>(I->getType()->getElementType()) && 220 AnalyzeIndirectGlobalMemory(I)) 221 ++NumIndirectGlobalVars; 222 } 223 Readers.clear(); Writers.clear(); 224 } 225} 226 227/// AnalyzeUsesOfPointer - Look at all of the users of the specified pointer. 228/// If this is used by anything complex (i.e., the address escapes), return 229/// true. Also, while we are at it, keep track of those functions that read and 230/// write to the value. 231/// 232/// If OkayStoreDest is non-null, stores into this global are allowed. 233bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V, 234 std::vector<Function*> &Readers, 235 std::vector<Function*> &Writers, 236 GlobalValue *OkayStoreDest) { 237 if (!isa<PointerType>(V->getType())) return true; 238 239 for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI) 240 if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 241 Readers.push_back(LI->getParent()->getParent()); 242 } else if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) { 243 if (V == SI->getOperand(1)) { 244 Writers.push_back(SI->getParent()->getParent()); 245 } else if (SI->getOperand(1) != OkayStoreDest) { 246 return true; // Storing the pointer 247 } 248 } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) { 249 if (AnalyzeUsesOfPointer(GEP, Readers, Writers)) return true; 250 } else if (CallInst *CI = dyn_cast<CallInst>(*UI)) { 251 // Make sure that this is just the function being called, not that it is 252 // passing into the function. 253 for (unsigned i = 1, e = CI->getNumOperands(); i != e; ++i) 254 if (CI->getOperand(i) == V) return true; 255 } else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) { 256 // Make sure that this is just the function being called, not that it is 257 // passing into the function. 258 for (unsigned i = 3, e = II->getNumOperands(); i != e; ++i) 259 if (II->getOperand(i) == V) return true; 260 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(*UI)) { 261 if (CE->getOpcode() == Instruction::GetElementPtr || 262 CE->getOpcode() == Instruction::BitCast) { 263 if (AnalyzeUsesOfPointer(CE, Readers, Writers)) 264 return true; 265 } else { 266 return true; 267 } 268 } else if (ICmpInst *ICI = dyn_cast<ICmpInst>(*UI)) { 269 if (!isa<ConstantPointerNull>(ICI->getOperand(1))) 270 return true; // Allow comparison against null. 271 } else if (FreeInst *F = dyn_cast<FreeInst>(*UI)) { 272 Writers.push_back(F->getParent()->getParent()); 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 = getUnderlyingObject(SI->getOperand(0)); 312 313 if (isa<MallocInst>(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 // mark all globals read somewhere as being read by this function. 390 for (std::set<GlobalValue*>::iterator GI = ReadGlobals.begin(), 391 E = ReadGlobals.end(); GI != E; ++GI) 392 FR.GlobalInfo[*GI] |= Ref; 393 } 394 } else { 395 // Can't say anything useful. 396 KnowNothing = true; 397 } 398 continue; 399 } 400 401 for (CallGraphNode::iterator CI = SCC[i]->begin(), E = SCC[i]->end(); 402 CI != E && !KnowNothing; ++CI) 403 if (Function *Callee = CI->second->getFunction()) { 404 if (FunctionRecord *CalleeFR = getFunctionInfo(Callee)) { 405 // Propagate function effect up. 406 FunctionEffect |= CalleeFR->FunctionEffect; 407 408 // Incorporate callee's effects on globals into our info. 409 for (std::map<GlobalValue*, unsigned>::iterator GI = 410 CalleeFR->GlobalInfo.begin(), E = CalleeFR->GlobalInfo.end(); 411 GI != E; ++GI) 412 FR.GlobalInfo[GI->first] |= GI->second; 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 else if (isa<StoreInst>(*II)) 441 FunctionEffect |= Mod; 442 else if (isa<MallocInst>(*II) || isa<FreeInst>(*II)) 443 FunctionEffect |= ModRef; 444 445 if ((FunctionEffect & Mod) == 0) 446 ++NumReadMemFunctions; 447 if (FunctionEffect == 0) 448 ++NumNoMemFunctions; 449 FR.FunctionEffect = FunctionEffect; 450 451 // Finally, now that we know the full effect on this SCC, clone the 452 // information to each function in the SCC. 453 for (unsigned i = 1, e = SCC.size(); i != e; ++i) 454 FunctionInfo[SCC[i]->getFunction()] = FR; 455 } 456} 457 458 459 460/// alias - If one of the pointers is to a global that we are tracking, and the 461/// other is some random pointer, we know there cannot be an alias, because the 462/// address of the global isn't taken. 463AliasAnalysis::AliasResult 464GlobalsModRef::alias(const Value *V1, unsigned V1Size, 465 const Value *V2, unsigned V2Size) { 466 // Get the base object these pointers point to. 467 Value *UV1 = getUnderlyingObject(const_cast<Value*>(V1)); 468 Value *UV2 = getUnderlyingObject(const_cast<Value*>(V2)); 469 470 // If either of the underlying values is a global, they may be non-addr-taken 471 // globals, which we can answer queries about. 472 GlobalValue *GV1 = dyn_cast<GlobalValue>(UV1); 473 GlobalValue *GV2 = dyn_cast<GlobalValue>(UV2); 474 if (GV1 || GV2) { 475 // If the global's address is taken, pretend we don't know it's a pointer to 476 // the global. 477 if (GV1 && !NonAddressTakenGlobals.count(GV1)) GV1 = 0; 478 if (GV2 && !NonAddressTakenGlobals.count(GV2)) GV2 = 0; 479 480 // If the the two pointers are derived from two different non-addr-taken 481 // globals, or if one is and the other isn't, we know these can't alias. 482 if ((GV1 || GV2) && GV1 != GV2) 483 return NoAlias; 484 485 // Otherwise if they are both derived from the same addr-taken global, we 486 // can't know the two accesses don't overlap. 487 } 488 489 // These pointers may be based on the memory owned by an indirect global. If 490 // so, we may be able to handle this. First check to see if the base pointer 491 // is a direct load from an indirect global. 492 GV1 = GV2 = 0; 493 if (LoadInst *LI = dyn_cast<LoadInst>(UV1)) 494 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(LI->getOperand(0))) 495 if (IndirectGlobals.count(GV)) 496 GV1 = GV; 497 if (LoadInst *LI = dyn_cast<LoadInst>(UV2)) 498 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(LI->getOperand(0))) 499 if (IndirectGlobals.count(GV)) 500 GV2 = GV; 501 502 // These pointers may also be from an allocation for the indirect global. If 503 // so, also handle them. 504 if (AllocsForIndirectGlobals.count(UV1)) 505 GV1 = AllocsForIndirectGlobals[UV1]; 506 if (AllocsForIndirectGlobals.count(UV2)) 507 GV2 = AllocsForIndirectGlobals[UV2]; 508 509 // Now that we know whether the two pointers are related to indirect globals, 510 // use this to disambiguate the pointers. If either pointer is based on an 511 // indirect global and if they are not both based on the same indirect global, 512 // they cannot alias. 513 if ((GV1 || GV2) && GV1 != GV2) 514 return NoAlias; 515 516 return AliasAnalysis::alias(V1, V1Size, V2, V2Size); 517} 518 519AliasAnalysis::ModRefResult 520GlobalsModRef::getModRefInfo(CallSite CS, Value *P, unsigned Size) { 521 unsigned Known = ModRef; 522 523 // If we are asking for mod/ref info of a direct call with a pointer to a 524 // global we are tracking, return information if we have it. 525 if (GlobalValue *GV = dyn_cast<GlobalValue>(getUnderlyingObject(P))) 526 if (GV->hasInternalLinkage()) 527 if (Function *F = CS.getCalledFunction()) 528 if (NonAddressTakenGlobals.count(GV)) 529 if (FunctionRecord *FR = getFunctionInfo(F)) 530 Known = FR->getInfoForGlobal(GV); 531 532 if (Known == NoModRef) 533 return NoModRef; // No need to query other mod/ref analyses 534 return ModRefResult(Known & AliasAnalysis::getModRefInfo(CS, P, Size)); 535} 536 537 538//===----------------------------------------------------------------------===// 539// Methods to update the analysis as a result of the client transformation. 540// 541void GlobalsModRef::deleteValue(Value *V) { 542 if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) { 543 if (NonAddressTakenGlobals.erase(GV)) { 544 // This global might be an indirect global. If so, remove it and remove 545 // any AllocRelatedValues for it. 546 if (IndirectGlobals.erase(GV)) { 547 // Remove any entries in AllocsForIndirectGlobals for this global. 548 for (std::map<Value*, GlobalValue*>::iterator 549 I = AllocsForIndirectGlobals.begin(), 550 E = AllocsForIndirectGlobals.end(); I != E; ) { 551 if (I->second == GV) { 552 AllocsForIndirectGlobals.erase(I++); 553 } else { 554 ++I; 555 } 556 } 557 } 558 } 559 } 560 561 // Otherwise, if this is an allocation related to an indirect global, remove 562 // it. 563 AllocsForIndirectGlobals.erase(V); 564 565 AliasAnalysis::deleteValue(V); 566} 567 568void GlobalsModRef::copyValue(Value *From, Value *To) { 569 AliasAnalysis::copyValue(From, To); 570} 571