1 //===- CallGraphSCCPass.cpp - Pass that operates BU on call graph ---------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements the CallGraphSCCPass class, which is used for passes 10 // which are implemented as bottom-up traversals on the call graph. Because 11 // there may be cycles in the call graph, passes of this type operate on the 12 // call-graph in SCC order: that is, they process function bottom-up, except for 13 // recursive functions, which they process all at once. 14 // 15 //===----------------------------------------------------------------------===// 16 17 #include "llvm/Analysis/CallGraphSCCPass.h" 18 #include "llvm/ADT/DenseMap.h" 19 #include "llvm/ADT/SCCIterator.h" 20 #include "llvm/ADT/Statistic.h" 21 #include "llvm/ADT/StringExtras.h" 22 #include "llvm/Analysis/CallGraph.h" 23 #include "llvm/IR/AbstractCallSite.h" 24 #include "llvm/IR/Function.h" 25 #include "llvm/IR/Intrinsics.h" 26 #include "llvm/IR/LLVMContext.h" 27 #include "llvm/IR/LegacyPassManagers.h" 28 #include "llvm/IR/Module.h" 29 #include "llvm/IR/OptBisect.h" 30 #include "llvm/IR/PassTimingInfo.h" 31 #include "llvm/IR/PrintPasses.h" 32 #include "llvm/Pass.h" 33 #include "llvm/Support/CommandLine.h" 34 #include "llvm/Support/Debug.h" 35 #include "llvm/Support/Timer.h" 36 #include "llvm/Support/raw_ostream.h" 37 #include <cassert> 38 #include <string> 39 #include <utility> 40 #include <vector> 41 42 using namespace llvm; 43 44 #define DEBUG_TYPE "cgscc-passmgr" 45 46 namespace llvm { 47 cl::opt<unsigned> MaxDevirtIterations("max-devirt-iterations", cl::ReallyHidden, 48 cl::init(4)); 49 } 50 51 STATISTIC(MaxSCCIterations, "Maximum CGSCCPassMgr iterations on one SCC"); 52 53 //===----------------------------------------------------------------------===// 54 // CGPassManager 55 // 56 /// CGPassManager manages FPPassManagers and CallGraphSCCPasses. 57 58 namespace { 59 60 class CGPassManager : public ModulePass, public PMDataManager { 61 public: 62 static char ID; 63 64 explicit CGPassManager() : ModulePass(ID) {} 65 66 /// Execute all of the passes scheduled for execution. Keep track of 67 /// whether any of the passes modifies the module, and if so, return true. 68 bool runOnModule(Module &M) override; 69 70 using ModulePass::doInitialization; 71 using ModulePass::doFinalization; 72 73 bool doInitialization(CallGraph &CG); 74 bool doFinalization(CallGraph &CG); 75 76 /// Pass Manager itself does not invalidate any analysis info. 77 void getAnalysisUsage(AnalysisUsage &Info) const override { 78 // CGPassManager walks SCC and it needs CallGraph. 79 Info.addRequired<CallGraphWrapperPass>(); 80 Info.setPreservesAll(); 81 } 82 83 StringRef getPassName() const override { return "CallGraph Pass Manager"; } 84 85 PMDataManager *getAsPMDataManager() override { return this; } 86 Pass *getAsPass() override { return this; } 87 88 // Print passes managed by this manager 89 void dumpPassStructure(unsigned Offset) override { 90 errs().indent(Offset*2) << "Call Graph SCC Pass Manager\n"; 91 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) { 92 Pass *P = getContainedPass(Index); 93 P->dumpPassStructure(Offset + 1); 94 dumpLastUses(P, Offset+1); 95 } 96 } 97 98 Pass *getContainedPass(unsigned N) { 99 assert(N < PassVector.size() && "Pass number out of range!"); 100 return static_cast<Pass *>(PassVector[N]); 101 } 102 103 PassManagerType getPassManagerType() const override { 104 return PMT_CallGraphPassManager; 105 } 106 107 private: 108 bool RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG, 109 bool &DevirtualizedCall); 110 111 bool RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC, 112 CallGraph &CG, bool &CallGraphUpToDate, 113 bool &DevirtualizedCall); 114 bool RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG, 115 bool IsCheckingMode); 116 }; 117 118 } // end anonymous namespace. 119 120 char CGPassManager::ID = 0; 121 122 bool CGPassManager::RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC, 123 CallGraph &CG, bool &CallGraphUpToDate, 124 bool &DevirtualizedCall) { 125 bool Changed = false; 126 PMDataManager *PM = P->getAsPMDataManager(); 127 Module &M = CG.getModule(); 128 129 if (!PM) { 130 CallGraphSCCPass *CGSP = (CallGraphSCCPass *)P; 131 if (!CallGraphUpToDate) { 132 DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, false); 133 CallGraphUpToDate = true; 134 } 135 136 { 137 unsigned InstrCount, SCCCount = 0; 138 StringMap<std::pair<unsigned, unsigned>> FunctionToInstrCount; 139 bool EmitICRemark = M.shouldEmitInstrCountChangedRemark(); 140 TimeRegion PassTimer(getPassTimer(CGSP)); 141 if (EmitICRemark) 142 InstrCount = initSizeRemarkInfo(M, FunctionToInstrCount); 143 Changed = CGSP->runOnSCC(CurSCC); 144 145 if (EmitICRemark) { 146 // FIXME: Add getInstructionCount to CallGraphSCC. 147 SCCCount = M.getInstructionCount(); 148 // Is there a difference in the number of instructions in the module? 149 if (SCCCount != InstrCount) { 150 // Yep. Emit a remark and update InstrCount. 151 int64_t Delta = 152 static_cast<int64_t>(SCCCount) - static_cast<int64_t>(InstrCount); 153 emitInstrCountChangedRemark(P, M, Delta, InstrCount, 154 FunctionToInstrCount); 155 InstrCount = SCCCount; 156 } 157 } 158 } 159 160 // After the CGSCCPass is done, when assertions are enabled, use 161 // RefreshCallGraph to verify that the callgraph was correctly updated. 162 #ifndef NDEBUG 163 if (Changed) 164 RefreshCallGraph(CurSCC, CG, true); 165 #endif 166 167 return Changed; 168 } 169 170 assert(PM->getPassManagerType() == PMT_FunctionPassManager && 171 "Invalid CGPassManager member"); 172 FPPassManager *FPP = (FPPassManager*)P; 173 174 // Run pass P on all functions in the current SCC. 175 for (CallGraphNode *CGN : CurSCC) { 176 if (Function *F = CGN->getFunction()) { 177 dumpPassInfo(P, EXECUTION_MSG, ON_FUNCTION_MSG, F->getName()); 178 { 179 TimeRegion PassTimer(getPassTimer(FPP)); 180 Changed |= FPP->runOnFunction(*F); 181 } 182 F->getContext().yield(); 183 } 184 } 185 186 // The function pass(es) modified the IR, they may have clobbered the 187 // callgraph. 188 if (Changed && CallGraphUpToDate) { 189 LLVM_DEBUG(dbgs() << "CGSCCPASSMGR: Pass Dirtied SCC: " << P->getPassName() 190 << '\n'); 191 CallGraphUpToDate = false; 192 } 193 return Changed; 194 } 195 196 /// Scan the functions in the specified CFG and resync the 197 /// callgraph with the call sites found in it. This is used after 198 /// FunctionPasses have potentially munged the callgraph, and can be used after 199 /// CallGraphSCC passes to verify that they correctly updated the callgraph. 200 /// 201 /// This function returns true if it devirtualized an existing function call, 202 /// meaning it turned an indirect call into a direct call. This happens when 203 /// a function pass like GVN optimizes away stuff feeding the indirect call. 204 /// This never happens in checking mode. 205 bool CGPassManager::RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG, 206 bool CheckingMode) { 207 DenseMap<Value *, CallGraphNode *> Calls; 208 209 LLVM_DEBUG(dbgs() << "CGSCCPASSMGR: Refreshing SCC with " << CurSCC.size() 210 << " nodes:\n"; 211 for (CallGraphNode *CGN 212 : CurSCC) CGN->dump();); 213 214 bool MadeChange = false; 215 bool DevirtualizedCall = false; 216 217 // Scan all functions in the SCC. 218 unsigned FunctionNo = 0; 219 for (CallGraphSCC::iterator SCCIdx = CurSCC.begin(), E = CurSCC.end(); 220 SCCIdx != E; ++SCCIdx, ++FunctionNo) { 221 CallGraphNode *CGN = *SCCIdx; 222 Function *F = CGN->getFunction(); 223 if (!F || F->isDeclaration()) continue; 224 225 // Walk the function body looking for call sites. Sync up the call sites in 226 // CGN with those actually in the function. 227 228 // Keep track of the number of direct and indirect calls that were 229 // invalidated and removed. 230 unsigned NumDirectRemoved = 0, NumIndirectRemoved = 0; 231 232 CallGraphNode::iterator CGNEnd = CGN->end(); 233 234 auto RemoveAndCheckForDone = [&](CallGraphNode::iterator I) { 235 // Just remove the edge from the set of callees, keep track of whether 236 // I points to the last element of the vector. 237 bool WasLast = I + 1 == CGNEnd; 238 CGN->removeCallEdge(I); 239 240 // If I pointed to the last element of the vector, we have to bail out: 241 // iterator checking rejects comparisons of the resultant pointer with 242 // end. 243 if (WasLast) 244 return true; 245 246 CGNEnd = CGN->end(); 247 return false; 248 }; 249 250 // Get the set of call sites currently in the function. 251 for (CallGraphNode::iterator I = CGN->begin(); I != CGNEnd;) { 252 // Delete "reference" call records that do not have call instruction. We 253 // reinsert them as needed later. However, keep them in checking mode. 254 if (!I->first) { 255 if (CheckingMode) { 256 ++I; 257 continue; 258 } 259 if (RemoveAndCheckForDone(I)) 260 break; 261 continue; 262 } 263 264 // If this call site is null, then the function pass deleted the call 265 // entirely and the WeakTrackingVH nulled it out. 266 auto *Call = dyn_cast_or_null<CallBase>(*I->first); 267 if (!Call || 268 // If we've already seen this call site, then the FunctionPass RAUW'd 269 // one call with another, which resulted in two "uses" in the edge 270 // list of the same call. 271 Calls.count(Call)) { 272 assert(!CheckingMode && 273 "CallGraphSCCPass did not update the CallGraph correctly!"); 274 275 // If this was an indirect call site, count it. 276 if (!I->second->getFunction()) 277 ++NumIndirectRemoved; 278 else 279 ++NumDirectRemoved; 280 281 if (RemoveAndCheckForDone(I)) 282 break; 283 continue; 284 } 285 286 assert(!Calls.count(Call) && "Call site occurs in node multiple times"); 287 288 if (Call) { 289 Function *Callee = Call->getCalledFunction(); 290 // Ignore intrinsics because they're not really function calls. 291 if (!Callee || !(Callee->isIntrinsic())) 292 Calls.insert(std::make_pair(Call, I->second)); 293 } 294 ++I; 295 } 296 297 // Loop over all of the instructions in the function, getting the callsites. 298 // Keep track of the number of direct/indirect calls added. 299 unsigned NumDirectAdded = 0, NumIndirectAdded = 0; 300 301 for (BasicBlock &BB : *F) 302 for (Instruction &I : BB) { 303 auto *Call = dyn_cast<CallBase>(&I); 304 if (!Call) 305 continue; 306 Function *Callee = Call->getCalledFunction(); 307 if (Callee && Callee->isIntrinsic()) 308 continue; 309 310 // If we are not in checking mode, insert potential callback calls as 311 // references. This is not a requirement but helps to iterate over the 312 // functions in the right order. 313 if (!CheckingMode) { 314 forEachCallbackFunction(*Call, [&](Function *CB) { 315 CGN->addCalledFunction(nullptr, CG.getOrInsertFunction(CB)); 316 }); 317 } 318 319 // If this call site already existed in the callgraph, just verify it 320 // matches up to expectations and remove it from Calls. 321 DenseMap<Value *, CallGraphNode *>::iterator ExistingIt = 322 Calls.find(Call); 323 if (ExistingIt != Calls.end()) { 324 CallGraphNode *ExistingNode = ExistingIt->second; 325 326 // Remove from Calls since we have now seen it. 327 Calls.erase(ExistingIt); 328 329 // Verify that the callee is right. 330 if (ExistingNode->getFunction() == Call->getCalledFunction()) 331 continue; 332 333 // If we are in checking mode, we are not allowed to actually mutate 334 // the callgraph. If this is a case where we can infer that the 335 // callgraph is less precise than it could be (e.g. an indirect call 336 // site could be turned direct), don't reject it in checking mode, and 337 // don't tweak it to be more precise. 338 if (CheckingMode && Call->getCalledFunction() && 339 ExistingNode->getFunction() == nullptr) 340 continue; 341 342 assert(!CheckingMode && 343 "CallGraphSCCPass did not update the CallGraph correctly!"); 344 345 // If not, we either went from a direct call to indirect, indirect to 346 // direct, or direct to different direct. 347 CallGraphNode *CalleeNode; 348 if (Function *Callee = Call->getCalledFunction()) { 349 CalleeNode = CG.getOrInsertFunction(Callee); 350 // Keep track of whether we turned an indirect call into a direct 351 // one. 352 if (!ExistingNode->getFunction()) { 353 DevirtualizedCall = true; 354 LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Devirtualized call to '" 355 << Callee->getName() << "'\n"); 356 } 357 } else { 358 CalleeNode = CG.getCallsExternalNode(); 359 } 360 361 // Update the edge target in CGN. 362 CGN->replaceCallEdge(*Call, *Call, CalleeNode); 363 MadeChange = true; 364 continue; 365 } 366 367 assert(!CheckingMode && 368 "CallGraphSCCPass did not update the CallGraph correctly!"); 369 370 // If the call site didn't exist in the CGN yet, add it. 371 CallGraphNode *CalleeNode; 372 if (Function *Callee = Call->getCalledFunction()) { 373 CalleeNode = CG.getOrInsertFunction(Callee); 374 ++NumDirectAdded; 375 } else { 376 CalleeNode = CG.getCallsExternalNode(); 377 ++NumIndirectAdded; 378 } 379 380 CGN->addCalledFunction(Call, CalleeNode); 381 MadeChange = true; 382 } 383 384 // We scanned the old callgraph node, removing invalidated call sites and 385 // then added back newly found call sites. One thing that can happen is 386 // that an old indirect call site was deleted and replaced with a new direct 387 // call. In this case, we have devirtualized a call, and CGSCCPM would like 388 // to iteratively optimize the new code. Unfortunately, we don't really 389 // have a great way to detect when this happens. As an approximation, we 390 // just look at whether the number of indirect calls is reduced and the 391 // number of direct calls is increased. There are tons of ways to fool this 392 // (e.g. DCE'ing an indirect call and duplicating an unrelated block with a 393 // direct call) but this is close enough. 394 if (NumIndirectRemoved > NumIndirectAdded && 395 NumDirectRemoved < NumDirectAdded) 396 DevirtualizedCall = true; 397 398 // After scanning this function, if we still have entries in callsites, then 399 // they are dangling pointers. WeakTrackingVH should save us for this, so 400 // abort if 401 // this happens. 402 assert(Calls.empty() && "Dangling pointers found in call sites map"); 403 404 // Periodically do an explicit clear to remove tombstones when processing 405 // large scc's. 406 if ((FunctionNo & 15) == 15) 407 Calls.clear(); 408 } 409 410 LLVM_DEBUG(if (MadeChange) { 411 dbgs() << "CGSCCPASSMGR: Refreshed SCC is now:\n"; 412 for (CallGraphNode *CGN : CurSCC) 413 CGN->dump(); 414 if (DevirtualizedCall) 415 dbgs() << "CGSCCPASSMGR: Refresh devirtualized a call!\n"; 416 } else { 417 dbgs() << "CGSCCPASSMGR: SCC Refresh didn't change call graph.\n"; 418 }); 419 (void)MadeChange; 420 421 return DevirtualizedCall; 422 } 423 424 /// Execute the body of the entire pass manager on the specified SCC. 425 /// This keeps track of whether a function pass devirtualizes 426 /// any calls and returns it in DevirtualizedCall. 427 bool CGPassManager::RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG, 428 bool &DevirtualizedCall) { 429 bool Changed = false; 430 431 // Keep track of whether the callgraph is known to be up-to-date or not. 432 // The CGSSC pass manager runs two types of passes: 433 // CallGraphSCC Passes and other random function passes. Because other 434 // random function passes are not CallGraph aware, they may clobber the 435 // call graph by introducing new calls or deleting other ones. This flag 436 // is set to false when we run a function pass so that we know to clean up 437 // the callgraph when we need to run a CGSCCPass again. 438 bool CallGraphUpToDate = true; 439 440 // Run all passes on current SCC. 441 for (unsigned PassNo = 0, e = getNumContainedPasses(); 442 PassNo != e; ++PassNo) { 443 Pass *P = getContainedPass(PassNo); 444 445 // If we're in -debug-pass=Executions mode, construct the SCC node list, 446 // otherwise avoid constructing this string as it is expensive. 447 if (isPassDebuggingExecutionsOrMore()) { 448 std::string Functions; 449 #ifndef NDEBUG 450 raw_string_ostream OS(Functions); 451 ListSeparator LS; 452 for (const CallGraphNode *CGN : CurSCC) { 453 OS << LS; 454 CGN->print(OS); 455 } 456 OS.flush(); 457 #endif 458 dumpPassInfo(P, EXECUTION_MSG, ON_CG_MSG, Functions); 459 } 460 dumpRequiredSet(P); 461 462 initializeAnalysisImpl(P); 463 464 #ifdef EXPENSIVE_CHECKS 465 uint64_t RefHash = P->structuralHash(CG.getModule()); 466 #endif 467 468 // Actually run this pass on the current SCC. 469 bool LocalChanged = 470 RunPassOnSCC(P, CurSCC, CG, CallGraphUpToDate, DevirtualizedCall); 471 472 Changed |= LocalChanged; 473 474 #ifdef EXPENSIVE_CHECKS 475 if (!LocalChanged && (RefHash != P->structuralHash(CG.getModule()))) { 476 llvm::errs() << "Pass modifies its input and doesn't report it: " 477 << P->getPassName() << "\n"; 478 llvm_unreachable("Pass modifies its input and doesn't report it"); 479 } 480 #endif 481 if (LocalChanged) 482 dumpPassInfo(P, MODIFICATION_MSG, ON_CG_MSG, ""); 483 dumpPreservedSet(P); 484 485 verifyPreservedAnalysis(P); 486 if (LocalChanged) 487 removeNotPreservedAnalysis(P); 488 recordAvailableAnalysis(P); 489 removeDeadPasses(P, "", ON_CG_MSG); 490 } 491 492 // If the callgraph was left out of date (because the last pass run was a 493 // functionpass), refresh it before we move on to the next SCC. 494 if (!CallGraphUpToDate) 495 DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, false); 496 return Changed; 497 } 498 499 /// Execute all of the passes scheduled for execution. Keep track of 500 /// whether any of the passes modifies the module, and if so, return true. 501 bool CGPassManager::runOnModule(Module &M) { 502 CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph(); 503 bool Changed = doInitialization(CG); 504 505 // Walk the callgraph in bottom-up SCC order. 506 scc_iterator<CallGraph*> CGI = scc_begin(&CG); 507 508 CallGraphSCC CurSCC(CG, &CGI); 509 while (!CGI.isAtEnd()) { 510 // Copy the current SCC and increment past it so that the pass can hack 511 // on the SCC if it wants to without invalidating our iterator. 512 const std::vector<CallGraphNode *> &NodeVec = *CGI; 513 CurSCC.initialize(NodeVec); 514 ++CGI; 515 516 // At the top level, we run all the passes in this pass manager on the 517 // functions in this SCC. However, we support iterative compilation in the 518 // case where a function pass devirtualizes a call to a function. For 519 // example, it is very common for a function pass (often GVN or instcombine) 520 // to eliminate the addressing that feeds into a call. With that improved 521 // information, we would like the call to be an inline candidate, infer 522 // mod-ref information etc. 523 // 524 // Because of this, we allow iteration up to a specified iteration count. 525 // This only happens in the case of a devirtualized call, so we only burn 526 // compile time in the case that we're making progress. We also have a hard 527 // iteration count limit in case there is crazy code. 528 unsigned Iteration = 0; 529 bool DevirtualizedCall = false; 530 do { 531 LLVM_DEBUG(if (Iteration) dbgs() 532 << " SCCPASSMGR: Re-visiting SCC, iteration #" << Iteration 533 << '\n'); 534 DevirtualizedCall = false; 535 Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall); 536 } while (Iteration++ < MaxDevirtIterations && DevirtualizedCall); 537 538 if (DevirtualizedCall) 539 LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after " 540 << Iteration 541 << " times, due to -max-devirt-iterations\n"); 542 543 MaxSCCIterations.updateMax(Iteration); 544 } 545 Changed |= doFinalization(CG); 546 return Changed; 547 } 548 549 /// Initialize CG 550 bool CGPassManager::doInitialization(CallGraph &CG) { 551 bool Changed = false; 552 for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) { 553 if (PMDataManager *PM = getContainedPass(i)->getAsPMDataManager()) { 554 assert(PM->getPassManagerType() == PMT_FunctionPassManager && 555 "Invalid CGPassManager member"); 556 Changed |= ((FPPassManager*)PM)->doInitialization(CG.getModule()); 557 } else { 558 Changed |= ((CallGraphSCCPass*)getContainedPass(i))->doInitialization(CG); 559 } 560 } 561 return Changed; 562 } 563 564 /// Finalize CG 565 bool CGPassManager::doFinalization(CallGraph &CG) { 566 bool Changed = false; 567 for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) { 568 if (PMDataManager *PM = getContainedPass(i)->getAsPMDataManager()) { 569 assert(PM->getPassManagerType() == PMT_FunctionPassManager && 570 "Invalid CGPassManager member"); 571 Changed |= ((FPPassManager*)PM)->doFinalization(CG.getModule()); 572 } else { 573 Changed |= ((CallGraphSCCPass*)getContainedPass(i))->doFinalization(CG); 574 } 575 } 576 return Changed; 577 } 578 579 //===----------------------------------------------------------------------===// 580 // CallGraphSCC Implementation 581 //===----------------------------------------------------------------------===// 582 583 /// This informs the SCC and the pass manager that the specified 584 /// Old node has been deleted, and New is to be used in its place. 585 void CallGraphSCC::ReplaceNode(CallGraphNode *Old, CallGraphNode *New) { 586 assert(Old != New && "Should not replace node with self"); 587 for (unsigned i = 0; ; ++i) { 588 assert(i != Nodes.size() && "Node not in SCC"); 589 if (Nodes[i] != Old) continue; 590 if (New) 591 Nodes[i] = New; 592 else 593 Nodes.erase(Nodes.begin() + i); 594 break; 595 } 596 597 // Update the active scc_iterator so that it doesn't contain dangling 598 // pointers to the old CallGraphNode. 599 scc_iterator<CallGraph*> *CGI = (scc_iterator<CallGraph*>*)Context; 600 CGI->ReplaceNode(Old, New); 601 } 602 603 void CallGraphSCC::DeleteNode(CallGraphNode *Old) { 604 ReplaceNode(Old, /*New=*/nullptr); 605 } 606 607 //===----------------------------------------------------------------------===// 608 // CallGraphSCCPass Implementation 609 //===----------------------------------------------------------------------===// 610 611 /// Assign pass manager to manage this pass. 612 void CallGraphSCCPass::assignPassManager(PMStack &PMS, 613 PassManagerType PreferredType) { 614 // Find CGPassManager 615 while (!PMS.empty() && 616 PMS.top()->getPassManagerType() > PMT_CallGraphPassManager) 617 PMS.pop(); 618 619 assert(!PMS.empty() && "Unable to handle Call Graph Pass"); 620 CGPassManager *CGP; 621 622 if (PMS.top()->getPassManagerType() == PMT_CallGraphPassManager) 623 CGP = (CGPassManager*)PMS.top(); 624 else { 625 // Create new Call Graph SCC Pass Manager if it does not exist. 626 assert(!PMS.empty() && "Unable to create Call Graph Pass Manager"); 627 PMDataManager *PMD = PMS.top(); 628 629 // [1] Create new Call Graph Pass Manager 630 CGP = new CGPassManager(); 631 632 // [2] Set up new manager's top level manager 633 PMTopLevelManager *TPM = PMD->getTopLevelManager(); 634 TPM->addIndirectPassManager(CGP); 635 636 // [3] Assign manager to manage this new manager. This may create 637 // and push new managers into PMS 638 Pass *P = CGP; 639 TPM->schedulePass(P); 640 641 // [4] Push new manager into PMS 642 PMS.push(CGP); 643 } 644 645 CGP->add(this); 646 } 647 648 /// For this class, we declare that we require and preserve the call graph. 649 /// If the derived class implements this method, it should 650 /// always explicitly call the implementation here. 651 void CallGraphSCCPass::getAnalysisUsage(AnalysisUsage &AU) const { 652 AU.addRequired<CallGraphWrapperPass>(); 653 AU.addPreserved<CallGraphWrapperPass>(); 654 } 655 656 //===----------------------------------------------------------------------===// 657 // PrintCallGraphPass Implementation 658 //===----------------------------------------------------------------------===// 659 660 namespace { 661 662 /// PrintCallGraphPass - Print a Module corresponding to a call graph. 663 /// 664 class PrintCallGraphPass : public CallGraphSCCPass { 665 std::string Banner; 666 raw_ostream &OS; // raw_ostream to print on. 667 668 public: 669 static char ID; 670 671 PrintCallGraphPass(const std::string &B, raw_ostream &OS) 672 : CallGraphSCCPass(ID), Banner(B), OS(OS) {} 673 674 void getAnalysisUsage(AnalysisUsage &AU) const override { 675 AU.setPreservesAll(); 676 } 677 678 bool runOnSCC(CallGraphSCC &SCC) override { 679 bool BannerPrinted = false; 680 auto PrintBannerOnce = [&]() { 681 if (BannerPrinted) 682 return; 683 OS << Banner; 684 BannerPrinted = true; 685 }; 686 687 bool NeedModule = llvm::forcePrintModuleIR(); 688 if (isFunctionInPrintList("*") && NeedModule) { 689 PrintBannerOnce(); 690 OS << "\n"; 691 SCC.getCallGraph().getModule().print(OS, nullptr); 692 return false; 693 } 694 bool FoundFunction = false; 695 for (CallGraphNode *CGN : SCC) { 696 if (Function *F = CGN->getFunction()) { 697 if (!F->isDeclaration() && isFunctionInPrintList(F->getName())) { 698 FoundFunction = true; 699 if (!NeedModule) { 700 PrintBannerOnce(); 701 F->print(OS); 702 } 703 } 704 } else if (isFunctionInPrintList("*")) { 705 PrintBannerOnce(); 706 OS << "\nPrinting <null> Function\n"; 707 } 708 } 709 if (NeedModule && FoundFunction) { 710 PrintBannerOnce(); 711 OS << "\n"; 712 SCC.getCallGraph().getModule().print(OS, nullptr); 713 } 714 return false; 715 } 716 717 StringRef getPassName() const override { return "Print CallGraph IR"; } 718 }; 719 720 } // end anonymous namespace. 721 722 char PrintCallGraphPass::ID = 0; 723 724 Pass *CallGraphSCCPass::createPrinterPass(raw_ostream &OS, 725 const std::string &Banner) const { 726 return new PrintCallGraphPass(Banner, OS); 727 } 728 729 static std::string getDescription(const CallGraphSCC &SCC) { 730 std::string Desc = "SCC ("; 731 ListSeparator LS; 732 for (CallGraphNode *CGN : SCC) { 733 Desc += LS; 734 Function *F = CGN->getFunction(); 735 if (F) 736 Desc += F->getName(); 737 else 738 Desc += "<<null function>>"; 739 } 740 Desc += ")"; 741 return Desc; 742 } 743 744 bool CallGraphSCCPass::skipSCC(CallGraphSCC &SCC) const { 745 OptPassGate &Gate = 746 SCC.getCallGraph().getModule().getContext().getOptPassGate(); 747 return Gate.isEnabled() && 748 !Gate.shouldRunPass(this->getPassName(), getDescription(SCC)); 749 } 750 751 char DummyCGSCCPass::ID = 0; 752 753 INITIALIZE_PASS(DummyCGSCCPass, "DummyCGSCCPass", "DummyCGSCCPass", false, 754 false) 755