LiveVariables.cpp revision 261991
1//=- LiveVariables.cpp - Live Variable Analysis for Source CFGs ----------*-==// 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 Live Variables analysis for source-level CFGs. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Analysis/Analyses/LiveVariables.h" 15#include "clang/AST/Stmt.h" 16#include "clang/AST/StmtVisitor.h" 17#include "clang/Analysis/Analyses/PostOrderCFGView.h" 18#include "clang/Analysis/AnalysisContext.h" 19#include "clang/Analysis/CFG.h" 20#include "llvm/ADT/DenseMap.h" 21#include "llvm/ADT/PostOrderIterator.h" 22#include "llvm/Support/raw_ostream.h" 23#include <algorithm> 24#include <vector> 25 26using namespace clang; 27 28namespace { 29 30class DataflowWorklist { 31 SmallVector<const CFGBlock *, 20> worklist; 32 llvm::BitVector enqueuedBlocks; 33 PostOrderCFGView *POV; 34public: 35 DataflowWorklist(const CFG &cfg, AnalysisDeclContext &Ctx) 36 : enqueuedBlocks(cfg.getNumBlockIDs()), 37 POV(Ctx.getAnalysis<PostOrderCFGView>()) {} 38 39 void enqueueBlock(const CFGBlock *block); 40 void enqueueSuccessors(const CFGBlock *block); 41 void enqueuePredecessors(const CFGBlock *block); 42 43 const CFGBlock *dequeue(); 44 45 void sortWorklist(); 46}; 47 48} 49 50void DataflowWorklist::enqueueBlock(const clang::CFGBlock *block) { 51 if (block && !enqueuedBlocks[block->getBlockID()]) { 52 enqueuedBlocks[block->getBlockID()] = true; 53 worklist.push_back(block); 54 } 55} 56 57void DataflowWorklist::enqueueSuccessors(const clang::CFGBlock *block) { 58 const unsigned OldWorklistSize = worklist.size(); 59 for (CFGBlock::const_succ_iterator I = block->succ_begin(), 60 E = block->succ_end(); I != E; ++I) { 61 enqueueBlock(*I); 62 } 63 64 if (OldWorklistSize == 0 || OldWorklistSize == worklist.size()) 65 return; 66 67 sortWorklist(); 68} 69 70void DataflowWorklist::enqueuePredecessors(const clang::CFGBlock *block) { 71 const unsigned OldWorklistSize = worklist.size(); 72 for (CFGBlock::const_pred_iterator I = block->pred_begin(), 73 E = block->pred_end(); I != E; ++I) { 74 enqueueBlock(*I); 75 } 76 77 if (OldWorklistSize == 0 || OldWorklistSize == worklist.size()) 78 return; 79 80 sortWorklist(); 81} 82 83void DataflowWorklist::sortWorklist() { 84 std::sort(worklist.begin(), worklist.end(), POV->getComparator()); 85} 86 87const CFGBlock *DataflowWorklist::dequeue() { 88 if (worklist.empty()) 89 return 0; 90 const CFGBlock *b = worklist.pop_back_val(); 91 enqueuedBlocks[b->getBlockID()] = false; 92 return b; 93} 94 95namespace { 96class LiveVariablesImpl { 97public: 98 AnalysisDeclContext &analysisContext; 99 std::vector<LiveVariables::LivenessValues> cfgBlockValues; 100 llvm::ImmutableSet<const Stmt *>::Factory SSetFact; 101 llvm::ImmutableSet<const VarDecl *>::Factory DSetFact; 102 llvm::DenseMap<const CFGBlock *, LiveVariables::LivenessValues> blocksEndToLiveness; 103 llvm::DenseMap<const CFGBlock *, LiveVariables::LivenessValues> blocksBeginToLiveness; 104 llvm::DenseMap<const Stmt *, LiveVariables::LivenessValues> stmtsToLiveness; 105 llvm::DenseMap<const DeclRefExpr *, unsigned> inAssignment; 106 const bool killAtAssign; 107 108 LiveVariables::LivenessValues 109 merge(LiveVariables::LivenessValues valsA, 110 LiveVariables::LivenessValues valsB); 111 112 LiveVariables::LivenessValues runOnBlock(const CFGBlock *block, 113 LiveVariables::LivenessValues val, 114 LiveVariables::Observer *obs = 0); 115 116 void dumpBlockLiveness(const SourceManager& M); 117 118 LiveVariablesImpl(AnalysisDeclContext &ac, bool KillAtAssign) 119 : analysisContext(ac), 120 SSetFact(false), // Do not canonicalize ImmutableSets by default. 121 DSetFact(false), // This is a *major* performance win. 122 killAtAssign(KillAtAssign) {} 123}; 124} 125 126static LiveVariablesImpl &getImpl(void *x) { 127 return *((LiveVariablesImpl *) x); 128} 129 130//===----------------------------------------------------------------------===// 131// Operations and queries on LivenessValues. 132//===----------------------------------------------------------------------===// 133 134bool LiveVariables::LivenessValues::isLive(const Stmt *S) const { 135 return liveStmts.contains(S); 136} 137 138bool LiveVariables::LivenessValues::isLive(const VarDecl *D) const { 139 return liveDecls.contains(D); 140} 141 142namespace { 143 template <typename SET> 144 SET mergeSets(SET A, SET B) { 145 if (A.isEmpty()) 146 return B; 147 148 for (typename SET::iterator it = B.begin(), ei = B.end(); it != ei; ++it) { 149 A = A.add(*it); 150 } 151 return A; 152 } 153} 154 155void LiveVariables::Observer::anchor() { } 156 157LiveVariables::LivenessValues 158LiveVariablesImpl::merge(LiveVariables::LivenessValues valsA, 159 LiveVariables::LivenessValues valsB) { 160 161 llvm::ImmutableSetRef<const Stmt *> 162 SSetRefA(valsA.liveStmts.getRootWithoutRetain(), SSetFact.getTreeFactory()), 163 SSetRefB(valsB.liveStmts.getRootWithoutRetain(), SSetFact.getTreeFactory()); 164 165 166 llvm::ImmutableSetRef<const VarDecl *> 167 DSetRefA(valsA.liveDecls.getRootWithoutRetain(), DSetFact.getTreeFactory()), 168 DSetRefB(valsB.liveDecls.getRootWithoutRetain(), DSetFact.getTreeFactory()); 169 170 171 SSetRefA = mergeSets(SSetRefA, SSetRefB); 172 DSetRefA = mergeSets(DSetRefA, DSetRefB); 173 174 // asImmutableSet() canonicalizes the tree, allowing us to do an easy 175 // comparison afterwards. 176 return LiveVariables::LivenessValues(SSetRefA.asImmutableSet(), 177 DSetRefA.asImmutableSet()); 178} 179 180bool LiveVariables::LivenessValues::equals(const LivenessValues &V) const { 181 return liveStmts == V.liveStmts && liveDecls == V.liveDecls; 182} 183 184//===----------------------------------------------------------------------===// 185// Query methods. 186//===----------------------------------------------------------------------===// 187 188static bool isAlwaysAlive(const VarDecl *D) { 189 return D->hasGlobalStorage(); 190} 191 192bool LiveVariables::isLive(const CFGBlock *B, const VarDecl *D) { 193 return isAlwaysAlive(D) || getImpl(impl).blocksEndToLiveness[B].isLive(D); 194} 195 196bool LiveVariables::isLive(const Stmt *S, const VarDecl *D) { 197 return isAlwaysAlive(D) || getImpl(impl).stmtsToLiveness[S].isLive(D); 198} 199 200bool LiveVariables::isLive(const Stmt *Loc, const Stmt *S) { 201 return getImpl(impl).stmtsToLiveness[Loc].isLive(S); 202} 203 204//===----------------------------------------------------------------------===// 205// Dataflow computation. 206//===----------------------------------------------------------------------===// 207 208namespace { 209class TransferFunctions : public StmtVisitor<TransferFunctions> { 210 LiveVariablesImpl &LV; 211 LiveVariables::LivenessValues &val; 212 LiveVariables::Observer *observer; 213 const CFGBlock *currentBlock; 214public: 215 TransferFunctions(LiveVariablesImpl &im, 216 LiveVariables::LivenessValues &Val, 217 LiveVariables::Observer *Observer, 218 const CFGBlock *CurrentBlock) 219 : LV(im), val(Val), observer(Observer), currentBlock(CurrentBlock) {} 220 221 void VisitBinaryOperator(BinaryOperator *BO); 222 void VisitBlockExpr(BlockExpr *BE); 223 void VisitDeclRefExpr(DeclRefExpr *DR); 224 void VisitDeclStmt(DeclStmt *DS); 225 void VisitObjCForCollectionStmt(ObjCForCollectionStmt *OS); 226 void VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *UE); 227 void VisitUnaryOperator(UnaryOperator *UO); 228 void Visit(Stmt *S); 229}; 230} 231 232static const VariableArrayType *FindVA(QualType Ty) { 233 const Type *ty = Ty.getTypePtr(); 234 while (const ArrayType *VT = dyn_cast<ArrayType>(ty)) { 235 if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(VT)) 236 if (VAT->getSizeExpr()) 237 return VAT; 238 239 ty = VT->getElementType().getTypePtr(); 240 } 241 242 return 0; 243} 244 245static const Stmt *LookThroughStmt(const Stmt *S) { 246 while (S) { 247 if (const Expr *Ex = dyn_cast<Expr>(S)) 248 S = Ex->IgnoreParens(); 249 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(S)) { 250 S = EWC->getSubExpr(); 251 continue; 252 } 253 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(S)) { 254 S = OVE->getSourceExpr(); 255 continue; 256 } 257 break; 258 } 259 return S; 260} 261 262static void AddLiveStmt(llvm::ImmutableSet<const Stmt *> &Set, 263 llvm::ImmutableSet<const Stmt *>::Factory &F, 264 const Stmt *S) { 265 Set = F.add(Set, LookThroughStmt(S)); 266} 267 268void TransferFunctions::Visit(Stmt *S) { 269 if (observer) 270 observer->observeStmt(S, currentBlock, val); 271 272 StmtVisitor<TransferFunctions>::Visit(S); 273 274 if (isa<Expr>(S)) { 275 val.liveStmts = LV.SSetFact.remove(val.liveStmts, S); 276 } 277 278 // Mark all children expressions live. 279 280 switch (S->getStmtClass()) { 281 default: 282 break; 283 case Stmt::StmtExprClass: { 284 // For statement expressions, look through the compound statement. 285 S = cast<StmtExpr>(S)->getSubStmt(); 286 break; 287 } 288 case Stmt::CXXMemberCallExprClass: { 289 // Include the implicit "this" pointer as being live. 290 CXXMemberCallExpr *CE = cast<CXXMemberCallExpr>(S); 291 if (Expr *ImplicitObj = CE->getImplicitObjectArgument()) { 292 AddLiveStmt(val.liveStmts, LV.SSetFact, ImplicitObj); 293 } 294 break; 295 } 296 case Stmt::ObjCMessageExprClass: { 297 // In calls to super, include the implicit "self" pointer as being live. 298 ObjCMessageExpr *CE = cast<ObjCMessageExpr>(S); 299 if (CE->getReceiverKind() == ObjCMessageExpr::SuperInstance) 300 val.liveDecls = LV.DSetFact.add(val.liveDecls, 301 LV.analysisContext.getSelfDecl()); 302 break; 303 } 304 case Stmt::DeclStmtClass: { 305 const DeclStmt *DS = cast<DeclStmt>(S); 306 if (const VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl())) { 307 for (const VariableArrayType* VA = FindVA(VD->getType()); 308 VA != 0; VA = FindVA(VA->getElementType())) { 309 AddLiveStmt(val.liveStmts, LV.SSetFact, VA->getSizeExpr()); 310 } 311 } 312 break; 313 } 314 case Stmt::PseudoObjectExprClass: { 315 // A pseudo-object operation only directly consumes its result 316 // expression. 317 Expr *child = cast<PseudoObjectExpr>(S)->getResultExpr(); 318 if (!child) return; 319 if (OpaqueValueExpr *OV = dyn_cast<OpaqueValueExpr>(child)) 320 child = OV->getSourceExpr(); 321 child = child->IgnoreParens(); 322 val.liveStmts = LV.SSetFact.add(val.liveStmts, child); 323 return; 324 } 325 326 // FIXME: These cases eventually shouldn't be needed. 327 case Stmt::ExprWithCleanupsClass: { 328 S = cast<ExprWithCleanups>(S)->getSubExpr(); 329 break; 330 } 331 case Stmt::CXXBindTemporaryExprClass: { 332 S = cast<CXXBindTemporaryExpr>(S)->getSubExpr(); 333 break; 334 } 335 case Stmt::UnaryExprOrTypeTraitExprClass: { 336 // No need to unconditionally visit subexpressions. 337 return; 338 } 339 } 340 341 for (Stmt::child_iterator it = S->child_begin(), ei = S->child_end(); 342 it != ei; ++it) { 343 if (Stmt *child = *it) 344 AddLiveStmt(val.liveStmts, LV.SSetFact, child); 345 } 346} 347 348void TransferFunctions::VisitBinaryOperator(BinaryOperator *B) { 349 if (B->isAssignmentOp()) { 350 if (!LV.killAtAssign) 351 return; 352 353 // Assigning to a variable? 354 Expr *LHS = B->getLHS()->IgnoreParens(); 355 356 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) 357 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 358 // Assignments to references don't kill the ref's address 359 if (VD->getType()->isReferenceType()) 360 return; 361 362 if (!isAlwaysAlive(VD)) { 363 // The variable is now dead. 364 val.liveDecls = LV.DSetFact.remove(val.liveDecls, VD); 365 } 366 367 if (observer) 368 observer->observerKill(DR); 369 } 370 } 371} 372 373void TransferFunctions::VisitBlockExpr(BlockExpr *BE) { 374 AnalysisDeclContext::referenced_decls_iterator I, E; 375 llvm::tie(I, E) = 376 LV.analysisContext.getReferencedBlockVars(BE->getBlockDecl()); 377 for ( ; I != E ; ++I) { 378 const VarDecl *VD = *I; 379 if (isAlwaysAlive(VD)) 380 continue; 381 val.liveDecls = LV.DSetFact.add(val.liveDecls, VD); 382 } 383} 384 385void TransferFunctions::VisitDeclRefExpr(DeclRefExpr *DR) { 386 if (const VarDecl *D = dyn_cast<VarDecl>(DR->getDecl())) 387 if (!isAlwaysAlive(D) && LV.inAssignment.find(DR) == LV.inAssignment.end()) 388 val.liveDecls = LV.DSetFact.add(val.liveDecls, D); 389} 390 391void TransferFunctions::VisitDeclStmt(DeclStmt *DS) { 392 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE = DS->decl_end(); 393 DI != DE; ++DI) 394 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) { 395 if (!isAlwaysAlive(VD)) 396 val.liveDecls = LV.DSetFact.remove(val.liveDecls, VD); 397 } 398} 399 400void TransferFunctions::VisitObjCForCollectionStmt(ObjCForCollectionStmt *OS) { 401 // Kill the iteration variable. 402 DeclRefExpr *DR = 0; 403 const VarDecl *VD = 0; 404 405 Stmt *element = OS->getElement(); 406 if (DeclStmt *DS = dyn_cast<DeclStmt>(element)) { 407 VD = cast<VarDecl>(DS->getSingleDecl()); 408 } 409 else if ((DR = dyn_cast<DeclRefExpr>(cast<Expr>(element)->IgnoreParens()))) { 410 VD = cast<VarDecl>(DR->getDecl()); 411 } 412 413 if (VD) { 414 val.liveDecls = LV.DSetFact.remove(val.liveDecls, VD); 415 if (observer && DR) 416 observer->observerKill(DR); 417 } 418} 419 420void TransferFunctions:: 421VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *UE) 422{ 423 // While sizeof(var) doesn't technically extend the liveness of 'var', it 424 // does extent the liveness of metadata if 'var' is a VariableArrayType. 425 // We handle that special case here. 426 if (UE->getKind() != UETT_SizeOf || UE->isArgumentType()) 427 return; 428 429 const Expr *subEx = UE->getArgumentExpr(); 430 if (subEx->getType()->isVariableArrayType()) { 431 assert(subEx->isLValue()); 432 val.liveStmts = LV.SSetFact.add(val.liveStmts, subEx->IgnoreParens()); 433 } 434} 435 436void TransferFunctions::VisitUnaryOperator(UnaryOperator *UO) { 437 // Treat ++/-- as a kill. 438 // Note we don't actually have to do anything if we don't have an observer, 439 // since a ++/-- acts as both a kill and a "use". 440 if (!observer) 441 return; 442 443 switch (UO->getOpcode()) { 444 default: 445 return; 446 case UO_PostInc: 447 case UO_PostDec: 448 case UO_PreInc: 449 case UO_PreDec: 450 break; 451 } 452 453 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(UO->getSubExpr()->IgnoreParens())) 454 if (isa<VarDecl>(DR->getDecl())) { 455 // Treat ++/-- as a kill. 456 observer->observerKill(DR); 457 } 458} 459 460LiveVariables::LivenessValues 461LiveVariablesImpl::runOnBlock(const CFGBlock *block, 462 LiveVariables::LivenessValues val, 463 LiveVariables::Observer *obs) { 464 465 TransferFunctions TF(*this, val, obs, block); 466 467 // Visit the terminator (if any). 468 if (const Stmt *term = block->getTerminator()) 469 TF.Visit(const_cast<Stmt*>(term)); 470 471 // Apply the transfer function for all Stmts in the block. 472 for (CFGBlock::const_reverse_iterator it = block->rbegin(), 473 ei = block->rend(); it != ei; ++it) { 474 const CFGElement &elem = *it; 475 476 if (Optional<CFGAutomaticObjDtor> Dtor = 477 elem.getAs<CFGAutomaticObjDtor>()) { 478 val.liveDecls = DSetFact.add(val.liveDecls, Dtor->getVarDecl()); 479 continue; 480 } 481 482 if (!elem.getAs<CFGStmt>()) 483 continue; 484 485 const Stmt *S = elem.castAs<CFGStmt>().getStmt(); 486 TF.Visit(const_cast<Stmt*>(S)); 487 stmtsToLiveness[S] = val; 488 } 489 return val; 490} 491 492void LiveVariables::runOnAllBlocks(LiveVariables::Observer &obs) { 493 const CFG *cfg = getImpl(impl).analysisContext.getCFG(); 494 for (CFG::const_iterator it = cfg->begin(), ei = cfg->end(); it != ei; ++it) 495 getImpl(impl).runOnBlock(*it, getImpl(impl).blocksEndToLiveness[*it], &obs); 496} 497 498LiveVariables::LiveVariables(void *im) : impl(im) {} 499 500LiveVariables::~LiveVariables() { 501 delete (LiveVariablesImpl*) impl; 502} 503 504LiveVariables * 505LiveVariables::computeLiveness(AnalysisDeclContext &AC, 506 bool killAtAssign) { 507 508 // No CFG? Bail out. 509 CFG *cfg = AC.getCFG(); 510 if (!cfg) 511 return 0; 512 513 // The analysis currently has scalability issues for very large CFGs. 514 // Bail out if it looks too large. 515 if (cfg->getNumBlockIDs() > 300000) 516 return 0; 517 518 LiveVariablesImpl *LV = new LiveVariablesImpl(AC, killAtAssign); 519 520 // Construct the dataflow worklist. Enqueue the exit block as the 521 // start of the analysis. 522 DataflowWorklist worklist(*cfg, AC); 523 llvm::BitVector everAnalyzedBlock(cfg->getNumBlockIDs()); 524 525 // FIXME: we should enqueue using post order. 526 for (CFG::const_iterator it = cfg->begin(), ei = cfg->end(); it != ei; ++it) { 527 const CFGBlock *block = *it; 528 worklist.enqueueBlock(block); 529 530 // FIXME: Scan for DeclRefExprs using in the LHS of an assignment. 531 // We need to do this because we lack context in the reverse analysis 532 // to determine if a DeclRefExpr appears in such a context, and thus 533 // doesn't constitute a "use". 534 if (killAtAssign) 535 for (CFGBlock::const_iterator bi = block->begin(), be = block->end(); 536 bi != be; ++bi) { 537 if (Optional<CFGStmt> cs = bi->getAs<CFGStmt>()) { 538 if (const BinaryOperator *BO = 539 dyn_cast<BinaryOperator>(cs->getStmt())) { 540 if (BO->getOpcode() == BO_Assign) { 541 if (const DeclRefExpr *DR = 542 dyn_cast<DeclRefExpr>(BO->getLHS()->IgnoreParens())) { 543 LV->inAssignment[DR] = 1; 544 } 545 } 546 } 547 } 548 } 549 } 550 551 worklist.sortWorklist(); 552 553 while (const CFGBlock *block = worklist.dequeue()) { 554 // Determine if the block's end value has changed. If not, we 555 // have nothing left to do for this block. 556 LivenessValues &prevVal = LV->blocksEndToLiveness[block]; 557 558 // Merge the values of all successor blocks. 559 LivenessValues val; 560 for (CFGBlock::const_succ_iterator it = block->succ_begin(), 561 ei = block->succ_end(); it != ei; ++it) { 562 if (const CFGBlock *succ = *it) { 563 val = LV->merge(val, LV->blocksBeginToLiveness[succ]); 564 } 565 } 566 567 if (!everAnalyzedBlock[block->getBlockID()]) 568 everAnalyzedBlock[block->getBlockID()] = true; 569 else if (prevVal.equals(val)) 570 continue; 571 572 prevVal = val; 573 574 // Update the dataflow value for the start of this block. 575 LV->blocksBeginToLiveness[block] = LV->runOnBlock(block, val); 576 577 // Enqueue the value to the predecessors. 578 worklist.enqueuePredecessors(block); 579 } 580 581 return new LiveVariables(LV); 582} 583 584static bool compare_entries(const CFGBlock *A, const CFGBlock *B) { 585 return A->getBlockID() < B->getBlockID(); 586} 587 588static bool compare_vd_entries(const Decl *A, const Decl *B) { 589 SourceLocation ALoc = A->getLocStart(); 590 SourceLocation BLoc = B->getLocStart(); 591 return ALoc.getRawEncoding() < BLoc.getRawEncoding(); 592} 593 594void LiveVariables::dumpBlockLiveness(const SourceManager &M) { 595 getImpl(impl).dumpBlockLiveness(M); 596} 597 598void LiveVariablesImpl::dumpBlockLiveness(const SourceManager &M) { 599 std::vector<const CFGBlock *> vec; 600 for (llvm::DenseMap<const CFGBlock *, LiveVariables::LivenessValues>::iterator 601 it = blocksEndToLiveness.begin(), ei = blocksEndToLiveness.end(); 602 it != ei; ++it) { 603 vec.push_back(it->first); 604 } 605 std::sort(vec.begin(), vec.end(), compare_entries); 606 607 std::vector<const VarDecl*> declVec; 608 609 for (std::vector<const CFGBlock *>::iterator 610 it = vec.begin(), ei = vec.end(); it != ei; ++it) { 611 llvm::errs() << "\n[ B" << (*it)->getBlockID() 612 << " (live variables at block exit) ]\n"; 613 614 LiveVariables::LivenessValues vals = blocksEndToLiveness[*it]; 615 declVec.clear(); 616 617 for (llvm::ImmutableSet<const VarDecl *>::iterator si = 618 vals.liveDecls.begin(), 619 se = vals.liveDecls.end(); si != se; ++si) { 620 declVec.push_back(*si); 621 } 622 623 std::sort(declVec.begin(), declVec.end(), compare_vd_entries); 624 625 for (std::vector<const VarDecl*>::iterator di = declVec.begin(), 626 de = declVec.end(); di != de; ++di) { 627 llvm::errs() << " " << (*di)->getDeclName().getAsString() 628 << " <"; 629 (*di)->getLocation().dump(M); 630 llvm::errs() << ">\n"; 631 } 632 } 633 llvm::errs() << "\n"; 634} 635 636const void *LiveVariables::getTag() { static int x; return &x; } 637const void *RelaxedLiveVariables::getTag() { static int x; return &x; } 638