1 //===- CGSCCPassManager.cpp - Managing & running CGSCC passes -------------===// 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 #include "llvm/Analysis/CGSCCPassManager.h" 10 #include "llvm/ADT/ArrayRef.h" 11 #include "llvm/ADT/PriorityWorklist.h" 12 #include "llvm/ADT/STLExtras.h" 13 #include "llvm/ADT/SetVector.h" 14 #include "llvm/ADT/SmallPtrSet.h" 15 #include "llvm/ADT/SmallVector.h" 16 #include "llvm/ADT/iterator_range.h" 17 #include "llvm/Analysis/LazyCallGraph.h" 18 #include "llvm/IR/Constant.h" 19 #include "llvm/IR/InstIterator.h" 20 #include "llvm/IR/Instruction.h" 21 #include "llvm/IR/PassManager.h" 22 #include "llvm/IR/PassManagerImpl.h" 23 #include "llvm/IR/ValueHandle.h" 24 #include "llvm/Support/Casting.h" 25 #include "llvm/Support/CommandLine.h" 26 #include "llvm/Support/Debug.h" 27 #include "llvm/Support/ErrorHandling.h" 28 #include "llvm/Support/TimeProfiler.h" 29 #include "llvm/Support/raw_ostream.h" 30 #include <cassert> 31 #include <iterator> 32 #include <optional> 33 34 #define DEBUG_TYPE "cgscc" 35 36 using namespace llvm; 37 38 // Explicit template instantiations and specialization definitions for core 39 // template typedefs. 40 namespace llvm { 41 static cl::opt<bool> AbortOnMaxDevirtIterationsReached( 42 "abort-on-max-devirt-iterations-reached", 43 cl::desc("Abort when the max iterations for devirtualization CGSCC repeat " 44 "pass is reached")); 45 46 AnalysisKey ShouldNotRunFunctionPassesAnalysis::Key; 47 48 // Explicit instantiations for the core proxy templates. 49 template class AllAnalysesOn<LazyCallGraph::SCC>; 50 template class AnalysisManager<LazyCallGraph::SCC, LazyCallGraph &>; 51 template class PassManager<LazyCallGraph::SCC, CGSCCAnalysisManager, 52 LazyCallGraph &, CGSCCUpdateResult &>; 53 template class InnerAnalysisManagerProxy<CGSCCAnalysisManager, Module>; 54 template class OuterAnalysisManagerProxy<ModuleAnalysisManager, 55 LazyCallGraph::SCC, LazyCallGraph &>; 56 template class OuterAnalysisManagerProxy<CGSCCAnalysisManager, Function>; 57 58 /// Explicitly specialize the pass manager run method to handle call graph 59 /// updates. 60 template <> 61 PreservedAnalyses 62 PassManager<LazyCallGraph::SCC, CGSCCAnalysisManager, LazyCallGraph &, 63 CGSCCUpdateResult &>::run(LazyCallGraph::SCC &InitialC, 64 CGSCCAnalysisManager &AM, 65 LazyCallGraph &G, CGSCCUpdateResult &UR) { 66 // Request PassInstrumentation from analysis manager, will use it to run 67 // instrumenting callbacks for the passes later. 68 PassInstrumentation PI = 69 AM.getResult<PassInstrumentationAnalysis>(InitialC, G); 70 71 PreservedAnalyses PA = PreservedAnalyses::all(); 72 73 // The SCC may be refined while we are running passes over it, so set up 74 // a pointer that we can update. 75 LazyCallGraph::SCC *C = &InitialC; 76 77 // Get Function analysis manager from its proxy. 78 FunctionAnalysisManager &FAM = 79 AM.getCachedResult<FunctionAnalysisManagerCGSCCProxy>(*C)->getManager(); 80 81 for (auto &Pass : Passes) { 82 // Check the PassInstrumentation's BeforePass callbacks before running the 83 // pass, skip its execution completely if asked to (callback returns false). 84 if (!PI.runBeforePass(*Pass, *C)) 85 continue; 86 87 PreservedAnalyses PassPA = Pass->run(*C, AM, G, UR); 88 89 // Update the SCC if necessary. 90 C = UR.UpdatedC ? UR.UpdatedC : C; 91 if (UR.UpdatedC) { 92 // If C is updated, also create a proxy and update FAM inside the result. 93 auto *ResultFAMCP = 94 &AM.getResult<FunctionAnalysisManagerCGSCCProxy>(*C, G); 95 ResultFAMCP->updateFAM(FAM); 96 } 97 98 // Intersect the final preserved analyses to compute the aggregate 99 // preserved set for this pass manager. 100 PA.intersect(PassPA); 101 102 // If the CGSCC pass wasn't able to provide a valid updated SCC, the 103 // current SCC may simply need to be skipped if invalid. 104 if (UR.InvalidatedSCCs.count(C)) { 105 PI.runAfterPassInvalidated<LazyCallGraph::SCC>(*Pass, PassPA); 106 LLVM_DEBUG(dbgs() << "Skipping invalidated root or island SCC!\n"); 107 break; 108 } 109 110 // Check that we didn't miss any update scenario. 111 assert(C->begin() != C->end() && "Cannot have an empty SCC!"); 112 113 // Update the analysis manager as each pass runs and potentially 114 // invalidates analyses. 115 AM.invalidate(*C, PassPA); 116 117 PI.runAfterPass<LazyCallGraph::SCC>(*Pass, *C, PassPA); 118 } 119 120 // Before we mark all of *this* SCC's analyses as preserved below, intersect 121 // this with the cross-SCC preserved analysis set. This is used to allow 122 // CGSCC passes to mutate ancestor SCCs and still trigger proper invalidation 123 // for them. 124 UR.CrossSCCPA.intersect(PA); 125 126 // Invalidation was handled after each pass in the above loop for the current 127 // SCC. Therefore, the remaining analysis results in the AnalysisManager are 128 // preserved. We mark this with a set so that we don't need to inspect each 129 // one individually. 130 PA.preserveSet<AllAnalysesOn<LazyCallGraph::SCC>>(); 131 132 return PA; 133 } 134 135 PreservedAnalyses 136 ModuleToPostOrderCGSCCPassAdaptor::run(Module &M, ModuleAnalysisManager &AM) { 137 // Setup the CGSCC analysis manager from its proxy. 138 CGSCCAnalysisManager &CGAM = 139 AM.getResult<CGSCCAnalysisManagerModuleProxy>(M).getManager(); 140 141 // Get the call graph for this module. 142 LazyCallGraph &CG = AM.getResult<LazyCallGraphAnalysis>(M); 143 144 // Get Function analysis manager from its proxy. 145 FunctionAnalysisManager &FAM = 146 AM.getCachedResult<FunctionAnalysisManagerModuleProxy>(M)->getManager(); 147 148 // We keep worklists to allow us to push more work onto the pass manager as 149 // the passes are run. 150 SmallPriorityWorklist<LazyCallGraph::RefSCC *, 1> RCWorklist; 151 SmallPriorityWorklist<LazyCallGraph::SCC *, 1> CWorklist; 152 153 // Keep sets for invalidated SCCs that should be skipped when 154 // iterating off the worklists. 155 SmallPtrSet<LazyCallGraph::SCC *, 4> InvalidSCCSet; 156 157 SmallDenseSet<std::pair<LazyCallGraph::Node *, LazyCallGraph::SCC *>, 4> 158 InlinedInternalEdges; 159 160 SmallVector<Function *, 4> DeadFunctions; 161 162 CGSCCUpdateResult UR = {CWorklist, 163 InvalidSCCSet, 164 nullptr, 165 PreservedAnalyses::all(), 166 InlinedInternalEdges, 167 DeadFunctions, 168 {}}; 169 170 // Request PassInstrumentation from analysis manager, will use it to run 171 // instrumenting callbacks for the passes later. 172 PassInstrumentation PI = AM.getResult<PassInstrumentationAnalysis>(M); 173 174 PreservedAnalyses PA = PreservedAnalyses::all(); 175 CG.buildRefSCCs(); 176 for (LazyCallGraph::RefSCC &RC : 177 llvm::make_early_inc_range(CG.postorder_ref_sccs())) { 178 assert(RCWorklist.empty() && 179 "Should always start with an empty RefSCC worklist"); 180 // The postorder_ref_sccs range we are walking is lazily constructed, so 181 // we only push the first one onto the worklist. The worklist allows us 182 // to capture *new* RefSCCs created during transformations. 183 // 184 // We really want to form RefSCCs lazily because that makes them cheaper 185 // to update as the program is simplified and allows us to have greater 186 // cache locality as forming a RefSCC touches all the parts of all the 187 // functions within that RefSCC. 188 // 189 // We also eagerly increment the iterator to the next position because 190 // the CGSCC passes below may delete the current RefSCC. 191 RCWorklist.insert(&RC); 192 193 do { 194 LazyCallGraph::RefSCC *RC = RCWorklist.pop_back_val(); 195 assert(CWorklist.empty() && 196 "Should always start with an empty SCC worklist"); 197 198 LLVM_DEBUG(dbgs() << "Running an SCC pass across the RefSCC: " << *RC 199 << "\n"); 200 201 // The top of the worklist may *also* be the same SCC we just ran over 202 // (and invalidated for). Keep track of that last SCC we processed due 203 // to SCC update to avoid redundant processing when an SCC is both just 204 // updated itself and at the top of the worklist. 205 LazyCallGraph::SCC *LastUpdatedC = nullptr; 206 207 // Push the initial SCCs in reverse post-order as we'll pop off the 208 // back and so see this in post-order. 209 for (LazyCallGraph::SCC &C : llvm::reverse(*RC)) 210 CWorklist.insert(&C); 211 212 do { 213 LazyCallGraph::SCC *C = CWorklist.pop_back_val(); 214 // Due to call graph mutations, we may have invalid SCCs or SCCs from 215 // other RefSCCs in the worklist. The invalid ones are dead and the 216 // other RefSCCs should be queued above, so we just need to skip both 217 // scenarios here. 218 if (InvalidSCCSet.count(C)) { 219 LLVM_DEBUG(dbgs() << "Skipping an invalid SCC...\n"); 220 continue; 221 } 222 if (LastUpdatedC == C) { 223 LLVM_DEBUG(dbgs() << "Skipping redundant run on SCC: " << *C << "\n"); 224 continue; 225 } 226 // We used to also check if the current SCC is part of the current 227 // RefSCC and bail if it wasn't, since it should be in RCWorklist. 228 // However, this can cause compile time explosions in some cases on 229 // modules with a huge RefSCC. If a non-trivial amount of SCCs in the 230 // huge RefSCC can become their own child RefSCC, we create one child 231 // RefSCC, bail on the current RefSCC, visit the child RefSCC, revisit 232 // the huge RefSCC, and repeat. By visiting all SCCs in the original 233 // RefSCC we create all the child RefSCCs in one pass of the RefSCC, 234 // rather one pass of the RefSCC creating one child RefSCC at a time. 235 236 // Ensure we can proxy analysis updates from the CGSCC analysis manager 237 // into the Function analysis manager by getting a proxy here. 238 // This also needs to update the FunctionAnalysisManager, as this may be 239 // the first time we see this SCC. 240 CGAM.getResult<FunctionAnalysisManagerCGSCCProxy>(*C, CG).updateFAM( 241 FAM); 242 243 // Each time we visit a new SCC pulled off the worklist, 244 // a transformation of a child SCC may have also modified this parent 245 // and invalidated analyses. So we invalidate using the update record's 246 // cross-SCC preserved set. This preserved set is intersected by any 247 // CGSCC pass that handles invalidation (primarily pass managers) prior 248 // to marking its SCC as preserved. That lets us track everything that 249 // might need invalidation across SCCs without excessive invalidations 250 // on a single SCC. 251 // 252 // This essentially allows SCC passes to freely invalidate analyses 253 // of any ancestor SCC. If this becomes detrimental to successfully 254 // caching analyses, we could force each SCC pass to manually 255 // invalidate the analyses for any SCCs other than themselves which 256 // are mutated. However, that seems to lose the robustness of the 257 // pass-manager driven invalidation scheme. 258 CGAM.invalidate(*C, UR.CrossSCCPA); 259 260 do { 261 // Check that we didn't miss any update scenario. 262 assert(!InvalidSCCSet.count(C) && "Processing an invalid SCC!"); 263 assert(C->begin() != C->end() && "Cannot have an empty SCC!"); 264 265 LastUpdatedC = UR.UpdatedC; 266 UR.UpdatedC = nullptr; 267 268 // Check the PassInstrumentation's BeforePass callbacks before 269 // running the pass, skip its execution completely if asked to 270 // (callback returns false). 271 if (!PI.runBeforePass<LazyCallGraph::SCC>(*Pass, *C)) 272 continue; 273 274 PreservedAnalyses PassPA = Pass->run(*C, CGAM, CG, UR); 275 276 // Update the SCC and RefSCC if necessary. 277 C = UR.UpdatedC ? UR.UpdatedC : C; 278 279 if (UR.UpdatedC) { 280 // If we're updating the SCC, also update the FAM inside the proxy's 281 // result. 282 CGAM.getResult<FunctionAnalysisManagerCGSCCProxy>(*C, CG).updateFAM( 283 FAM); 284 } 285 286 // Intersect with the cross-SCC preserved set to capture any 287 // cross-SCC invalidation. 288 UR.CrossSCCPA.intersect(PassPA); 289 // Intersect the preserved set so that invalidation of module 290 // analyses will eventually occur when the module pass completes. 291 PA.intersect(PassPA); 292 293 // If the CGSCC pass wasn't able to provide a valid updated SCC, 294 // the current SCC may simply need to be skipped if invalid. 295 if (UR.InvalidatedSCCs.count(C)) { 296 PI.runAfterPassInvalidated<LazyCallGraph::SCC>(*Pass, PassPA); 297 LLVM_DEBUG(dbgs() << "Skipping invalidated root or island SCC!\n"); 298 break; 299 } 300 301 // Check that we didn't miss any update scenario. 302 assert(C->begin() != C->end() && "Cannot have an empty SCC!"); 303 304 // We handle invalidating the CGSCC analysis manager's information 305 // for the (potentially updated) SCC here. Note that any other SCCs 306 // whose structure has changed should have been invalidated by 307 // whatever was updating the call graph. This SCC gets invalidated 308 // late as it contains the nodes that were actively being 309 // processed. 310 CGAM.invalidate(*C, PassPA); 311 312 PI.runAfterPass<LazyCallGraph::SCC>(*Pass, *C, PassPA); 313 314 // The pass may have restructured the call graph and refined the 315 // current SCC and/or RefSCC. We need to update our current SCC and 316 // RefSCC pointers to follow these. Also, when the current SCC is 317 // refined, re-run the SCC pass over the newly refined SCC in order 318 // to observe the most precise SCC model available. This inherently 319 // cannot cycle excessively as it only happens when we split SCCs 320 // apart, at most converging on a DAG of single nodes. 321 // FIXME: If we ever start having RefSCC passes, we'll want to 322 // iterate there too. 323 if (UR.UpdatedC) 324 LLVM_DEBUG(dbgs() 325 << "Re-running SCC passes after a refinement of the " 326 "current SCC: " 327 << *UR.UpdatedC << "\n"); 328 329 // Note that both `C` and `RC` may at this point refer to deleted, 330 // invalid SCC and RefSCCs respectively. But we will short circuit 331 // the processing when we check them in the loop above. 332 } while (UR.UpdatedC); 333 } while (!CWorklist.empty()); 334 335 // We only need to keep internal inlined edge information within 336 // a RefSCC, clear it to save on space and let the next time we visit 337 // any of these functions have a fresh start. 338 InlinedInternalEdges.clear(); 339 } while (!RCWorklist.empty()); 340 } 341 342 CG.removeDeadFunctions(DeadFunctions); 343 for (Function *DeadF : DeadFunctions) 344 DeadF->eraseFromParent(); 345 346 #if defined(EXPENSIVE_CHECKS) 347 // Verify that the call graph is still valid. 348 CG.verify(); 349 #endif 350 351 // By definition we preserve the call garph, all SCC analyses, and the 352 // analysis proxies by handling them above and in any nested pass managers. 353 PA.preserveSet<AllAnalysesOn<LazyCallGraph::SCC>>(); 354 PA.preserve<LazyCallGraphAnalysis>(); 355 PA.preserve<CGSCCAnalysisManagerModuleProxy>(); 356 PA.preserve<FunctionAnalysisManagerModuleProxy>(); 357 return PA; 358 } 359 360 PreservedAnalyses DevirtSCCRepeatedPass::run(LazyCallGraph::SCC &InitialC, 361 CGSCCAnalysisManager &AM, 362 LazyCallGraph &CG, 363 CGSCCUpdateResult &UR) { 364 PreservedAnalyses PA = PreservedAnalyses::all(); 365 PassInstrumentation PI = 366 AM.getResult<PassInstrumentationAnalysis>(InitialC, CG); 367 368 // The SCC may be refined while we are running passes over it, so set up 369 // a pointer that we can update. 370 LazyCallGraph::SCC *C = &InitialC; 371 372 // Struct to track the counts of direct and indirect calls in each function 373 // of the SCC. 374 struct CallCount { 375 int Direct; 376 int Indirect; 377 }; 378 379 // Put value handles on all of the indirect calls and return the number of 380 // direct calls for each function in the SCC. 381 auto ScanSCC = [](LazyCallGraph::SCC &C, 382 SmallMapVector<Value *, WeakTrackingVH, 16> &CallHandles) { 383 assert(CallHandles.empty() && "Must start with a clear set of handles."); 384 385 SmallDenseMap<Function *, CallCount> CallCounts; 386 CallCount CountLocal = {0, 0}; 387 for (LazyCallGraph::Node &N : C) { 388 CallCount &Count = 389 CallCounts.insert(std::make_pair(&N.getFunction(), CountLocal)) 390 .first->second; 391 for (Instruction &I : instructions(N.getFunction())) 392 if (auto *CB = dyn_cast<CallBase>(&I)) { 393 if (CB->getCalledFunction()) { 394 ++Count.Direct; 395 } else { 396 ++Count.Indirect; 397 CallHandles.insert({CB, WeakTrackingVH(CB)}); 398 } 399 } 400 } 401 402 return CallCounts; 403 }; 404 405 UR.IndirectVHs.clear(); 406 // Populate the initial call handles and get the initial call counts. 407 auto CallCounts = ScanSCC(*C, UR.IndirectVHs); 408 409 for (int Iteration = 0;; ++Iteration) { 410 if (!PI.runBeforePass<LazyCallGraph::SCC>(*Pass, *C)) 411 continue; 412 413 PreservedAnalyses PassPA = Pass->run(*C, AM, CG, UR); 414 415 PA.intersect(PassPA); 416 417 // If the CGSCC pass wasn't able to provide a valid updated SCC, the 418 // current SCC may simply need to be skipped if invalid. 419 if (UR.InvalidatedSCCs.count(C)) { 420 PI.runAfterPassInvalidated<LazyCallGraph::SCC>(*Pass, PassPA); 421 LLVM_DEBUG(dbgs() << "Skipping invalidated root or island SCC!\n"); 422 break; 423 } 424 425 // Update the analysis manager with each run and intersect the total set 426 // of preserved analyses so we're ready to iterate. 427 AM.invalidate(*C, PassPA); 428 429 PI.runAfterPass<LazyCallGraph::SCC>(*Pass, *C, PassPA); 430 431 // If the SCC structure has changed, bail immediately and let the outer 432 // CGSCC layer handle any iteration to reflect the refined structure. 433 if (UR.UpdatedC && UR.UpdatedC != C) 434 break; 435 436 assert(C->begin() != C->end() && "Cannot have an empty SCC!"); 437 438 // Check whether any of the handles were devirtualized. 439 bool Devirt = llvm::any_of(UR.IndirectVHs, [](auto &P) -> bool { 440 if (P.second) { 441 if (CallBase *CB = dyn_cast<CallBase>(P.second)) { 442 if (CB->getCalledFunction()) { 443 LLVM_DEBUG(dbgs() << "Found devirtualized call: " << *CB << "\n"); 444 return true; 445 } 446 } 447 } 448 return false; 449 }); 450 451 // Rescan to build up a new set of handles and count how many direct 452 // calls remain. If we decide to iterate, this also sets up the input to 453 // the next iteration. 454 UR.IndirectVHs.clear(); 455 auto NewCallCounts = ScanSCC(*C, UR.IndirectVHs); 456 457 // If we haven't found an explicit devirtualization already see if we 458 // have decreased the number of indirect calls and increased the number 459 // of direct calls for any function in the SCC. This can be fooled by all 460 // manner of transformations such as DCE and other things, but seems to 461 // work well in practice. 462 if (!Devirt) 463 // Iterate over the keys in NewCallCounts, if Function also exists in 464 // CallCounts, make the check below. 465 for (auto &Pair : NewCallCounts) { 466 auto &CallCountNew = Pair.second; 467 auto CountIt = CallCounts.find(Pair.first); 468 if (CountIt != CallCounts.end()) { 469 const auto &CallCountOld = CountIt->second; 470 if (CallCountOld.Indirect > CallCountNew.Indirect && 471 CallCountOld.Direct < CallCountNew.Direct) { 472 Devirt = true; 473 break; 474 } 475 } 476 } 477 478 if (!Devirt) { 479 break; 480 } 481 482 // Otherwise, if we've already hit our max, we're done. 483 if (Iteration >= MaxIterations) { 484 if (AbortOnMaxDevirtIterationsReached) 485 report_fatal_error("Max devirtualization iterations reached"); 486 LLVM_DEBUG( 487 dbgs() << "Found another devirtualization after hitting the max " 488 "number of repetitions (" 489 << MaxIterations << ") on SCC: " << *C << "\n"); 490 break; 491 } 492 493 LLVM_DEBUG( 494 dbgs() << "Repeating an SCC pass after finding a devirtualization in: " 495 << *C << "\n"); 496 497 // Move over the new call counts in preparation for iterating. 498 CallCounts = std::move(NewCallCounts); 499 } 500 501 // Note that we don't add any preserved entries here unlike a more normal 502 // "pass manager" because we only handle invalidation *between* iterations, 503 // not after the last iteration. 504 return PA; 505 } 506 507 PreservedAnalyses CGSCCToFunctionPassAdaptor::run(LazyCallGraph::SCC &C, 508 CGSCCAnalysisManager &AM, 509 LazyCallGraph &CG, 510 CGSCCUpdateResult &UR) { 511 // Setup the function analysis manager from its proxy. 512 FunctionAnalysisManager &FAM = 513 AM.getResult<FunctionAnalysisManagerCGSCCProxy>(C, CG).getManager(); 514 515 SmallVector<LazyCallGraph::Node *, 4> Nodes; 516 for (LazyCallGraph::Node &N : C) 517 Nodes.push_back(&N); 518 519 // The SCC may get split while we are optimizing functions due to deleting 520 // edges. If this happens, the current SCC can shift, so keep track of 521 // a pointer we can overwrite. 522 LazyCallGraph::SCC *CurrentC = &C; 523 524 LLVM_DEBUG(dbgs() << "Running function passes across an SCC: " << C << "\n"); 525 526 PreservedAnalyses PA = PreservedAnalyses::all(); 527 for (LazyCallGraph::Node *N : Nodes) { 528 // Skip nodes from other SCCs. These may have been split out during 529 // processing. We'll eventually visit those SCCs and pick up the nodes 530 // there. 531 if (CG.lookupSCC(*N) != CurrentC) 532 continue; 533 534 Function &F = N->getFunction(); 535 536 if (NoRerun && FAM.getCachedResult<ShouldNotRunFunctionPassesAnalysis>(F)) 537 continue; 538 539 PassInstrumentation PI = FAM.getResult<PassInstrumentationAnalysis>(F); 540 if (!PI.runBeforePass<Function>(*Pass, F)) 541 continue; 542 543 PreservedAnalyses PassPA = Pass->run(F, FAM); 544 545 // We know that the function pass couldn't have invalidated any other 546 // function's analyses (that's the contract of a function pass), so 547 // directly handle the function analysis manager's invalidation here. 548 FAM.invalidate(F, EagerlyInvalidate ? PreservedAnalyses::none() : PassPA); 549 550 PI.runAfterPass<Function>(*Pass, F, PassPA); 551 552 // Then intersect the preserved set so that invalidation of module 553 // analyses will eventually occur when the module pass completes. 554 PA.intersect(std::move(PassPA)); 555 556 // If the call graph hasn't been preserved, update it based on this 557 // function pass. This may also update the current SCC to point to 558 // a smaller, more refined SCC. 559 auto PAC = PA.getChecker<LazyCallGraphAnalysis>(); 560 if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<Module>>()) { 561 CurrentC = &updateCGAndAnalysisManagerForFunctionPass(CG, *CurrentC, *N, 562 AM, UR, FAM); 563 assert(CG.lookupSCC(*N) == CurrentC && 564 "Current SCC not updated to the SCC containing the current node!"); 565 } 566 } 567 568 // By definition we preserve the proxy. And we preserve all analyses on 569 // Functions. This precludes *any* invalidation of function analyses by the 570 // proxy, but that's OK because we've taken care to invalidate analyses in 571 // the function analysis manager incrementally above. 572 PA.preserveSet<AllAnalysesOn<Function>>(); 573 PA.preserve<FunctionAnalysisManagerCGSCCProxy>(); 574 575 // We've also ensured that we updated the call graph along the way. 576 PA.preserve<LazyCallGraphAnalysis>(); 577 578 return PA; 579 } 580 581 bool CGSCCAnalysisManagerModuleProxy::Result::invalidate( 582 Module &M, const PreservedAnalyses &PA, 583 ModuleAnalysisManager::Invalidator &Inv) { 584 // If literally everything is preserved, we're done. 585 if (PA.areAllPreserved()) 586 return false; // This is still a valid proxy. 587 588 // If this proxy or the call graph is going to be invalidated, we also need 589 // to clear all the keys coming from that analysis. 590 // 591 // We also directly invalidate the FAM's module proxy if necessary, and if 592 // that proxy isn't preserved we can't preserve this proxy either. We rely on 593 // it to handle module -> function analysis invalidation in the face of 594 // structural changes and so if it's unavailable we conservatively clear the 595 // entire SCC layer as well rather than trying to do invalidation ourselves. 596 auto PAC = PA.getChecker<CGSCCAnalysisManagerModuleProxy>(); 597 if (!(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Module>>()) || 598 Inv.invalidate<LazyCallGraphAnalysis>(M, PA) || 599 Inv.invalidate<FunctionAnalysisManagerModuleProxy>(M, PA)) { 600 InnerAM->clear(); 601 602 // And the proxy itself should be marked as invalid so that we can observe 603 // the new call graph. This isn't strictly necessary because we cheat 604 // above, but is still useful. 605 return true; 606 } 607 608 // Directly check if the relevant set is preserved so we can short circuit 609 // invalidating SCCs below. 610 bool AreSCCAnalysesPreserved = 611 PA.allAnalysesInSetPreserved<AllAnalysesOn<LazyCallGraph::SCC>>(); 612 613 // Ok, we have a graph, so we can propagate the invalidation down into it. 614 G->buildRefSCCs(); 615 for (auto &RC : G->postorder_ref_sccs()) 616 for (auto &C : RC) { 617 std::optional<PreservedAnalyses> InnerPA; 618 619 // Check to see whether the preserved set needs to be adjusted based on 620 // module-level analysis invalidation triggering deferred invalidation 621 // for this SCC. 622 if (auto *OuterProxy = 623 InnerAM->getCachedResult<ModuleAnalysisManagerCGSCCProxy>(C)) 624 for (const auto &OuterInvalidationPair : 625 OuterProxy->getOuterInvalidations()) { 626 AnalysisKey *OuterAnalysisID = OuterInvalidationPair.first; 627 const auto &InnerAnalysisIDs = OuterInvalidationPair.second; 628 if (Inv.invalidate(OuterAnalysisID, M, PA)) { 629 if (!InnerPA) 630 InnerPA = PA; 631 for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs) 632 InnerPA->abandon(InnerAnalysisID); 633 } 634 } 635 636 // Check if we needed a custom PA set. If so we'll need to run the inner 637 // invalidation. 638 if (InnerPA) { 639 InnerAM->invalidate(C, *InnerPA); 640 continue; 641 } 642 643 // Otherwise we only need to do invalidation if the original PA set didn't 644 // preserve all SCC analyses. 645 if (!AreSCCAnalysesPreserved) 646 InnerAM->invalidate(C, PA); 647 } 648 649 // Return false to indicate that this result is still a valid proxy. 650 return false; 651 } 652 653 template <> 654 CGSCCAnalysisManagerModuleProxy::Result 655 CGSCCAnalysisManagerModuleProxy::run(Module &M, ModuleAnalysisManager &AM) { 656 // Force the Function analysis manager to also be available so that it can 657 // be accessed in an SCC analysis and proxied onward to function passes. 658 // FIXME: It is pretty awkward to just drop the result here and assert that 659 // we can find it again later. 660 (void)AM.getResult<FunctionAnalysisManagerModuleProxy>(M); 661 662 return Result(*InnerAM, AM.getResult<LazyCallGraphAnalysis>(M)); 663 } 664 665 AnalysisKey FunctionAnalysisManagerCGSCCProxy::Key; 666 667 FunctionAnalysisManagerCGSCCProxy::Result 668 FunctionAnalysisManagerCGSCCProxy::run(LazyCallGraph::SCC &C, 669 CGSCCAnalysisManager &AM, 670 LazyCallGraph &CG) { 671 // Note: unconditionally getting checking that the proxy exists may get it at 672 // this point. There are cases when this is being run unnecessarily, but 673 // it is cheap and having the assertion in place is more valuable. 674 auto &MAMProxy = AM.getResult<ModuleAnalysisManagerCGSCCProxy>(C, CG); 675 Module &M = *C.begin()->getFunction().getParent(); 676 bool ProxyExists = 677 MAMProxy.cachedResultExists<FunctionAnalysisManagerModuleProxy>(M); 678 assert(ProxyExists && 679 "The CGSCC pass manager requires that the FAM module proxy is run " 680 "on the module prior to entering the CGSCC walk"); 681 (void)ProxyExists; 682 683 // We just return an empty result. The caller will use the updateFAM interface 684 // to correctly register the relevant FunctionAnalysisManager based on the 685 // context in which this proxy is run. 686 return Result(); 687 } 688 689 bool FunctionAnalysisManagerCGSCCProxy::Result::invalidate( 690 LazyCallGraph::SCC &C, const PreservedAnalyses &PA, 691 CGSCCAnalysisManager::Invalidator &Inv) { 692 // If literally everything is preserved, we're done. 693 if (PA.areAllPreserved()) 694 return false; // This is still a valid proxy. 695 696 // All updates to preserve valid results are done below, so we don't need to 697 // invalidate this proxy. 698 // 699 // Note that in order to preserve this proxy, a module pass must ensure that 700 // the FAM has been completely updated to handle the deletion of functions. 701 // Specifically, any FAM-cached results for those functions need to have been 702 // forcibly cleared. When preserved, this proxy will only invalidate results 703 // cached on functions *still in the module* at the end of the module pass. 704 auto PAC = PA.getChecker<FunctionAnalysisManagerCGSCCProxy>(); 705 if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<LazyCallGraph::SCC>>()) { 706 for (LazyCallGraph::Node &N : C) 707 FAM->invalidate(N.getFunction(), PA); 708 709 return false; 710 } 711 712 // Directly check if the relevant set is preserved. 713 bool AreFunctionAnalysesPreserved = 714 PA.allAnalysesInSetPreserved<AllAnalysesOn<Function>>(); 715 716 // Now walk all the functions to see if any inner analysis invalidation is 717 // necessary. 718 for (LazyCallGraph::Node &N : C) { 719 Function &F = N.getFunction(); 720 std::optional<PreservedAnalyses> FunctionPA; 721 722 // Check to see whether the preserved set needs to be pruned based on 723 // SCC-level analysis invalidation that triggers deferred invalidation 724 // registered with the outer analysis manager proxy for this function. 725 if (auto *OuterProxy = 726 FAM->getCachedResult<CGSCCAnalysisManagerFunctionProxy>(F)) 727 for (const auto &OuterInvalidationPair : 728 OuterProxy->getOuterInvalidations()) { 729 AnalysisKey *OuterAnalysisID = OuterInvalidationPair.first; 730 const auto &InnerAnalysisIDs = OuterInvalidationPair.second; 731 if (Inv.invalidate(OuterAnalysisID, C, PA)) { 732 if (!FunctionPA) 733 FunctionPA = PA; 734 for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs) 735 FunctionPA->abandon(InnerAnalysisID); 736 } 737 } 738 739 // Check if we needed a custom PA set, and if so we'll need to run the 740 // inner invalidation. 741 if (FunctionPA) { 742 FAM->invalidate(F, *FunctionPA); 743 continue; 744 } 745 746 // Otherwise we only need to do invalidation if the original PA set didn't 747 // preserve all function analyses. 748 if (!AreFunctionAnalysesPreserved) 749 FAM->invalidate(F, PA); 750 } 751 752 // Return false to indicate that this result is still a valid proxy. 753 return false; 754 } 755 756 } // end namespace llvm 757 758 /// When a new SCC is created for the graph we first update the 759 /// FunctionAnalysisManager in the Proxy's result. 760 /// As there might be function analysis results cached for the functions now in 761 /// that SCC, two forms of updates are required. 762 /// 763 /// First, a proxy from the SCC to the FunctionAnalysisManager needs to be 764 /// created so that any subsequent invalidation events to the SCC are 765 /// propagated to the function analysis results cached for functions within it. 766 /// 767 /// Second, if any of the functions within the SCC have analysis results with 768 /// outer analysis dependencies, then those dependencies would point to the 769 /// *wrong* SCC's analysis result. We forcibly invalidate the necessary 770 /// function analyses so that they don't retain stale handles. 771 static void updateNewSCCFunctionAnalyses(LazyCallGraph::SCC &C, 772 LazyCallGraph &G, 773 CGSCCAnalysisManager &AM, 774 FunctionAnalysisManager &FAM) { 775 AM.getResult<FunctionAnalysisManagerCGSCCProxy>(C, G).updateFAM(FAM); 776 777 // Now walk the functions in this SCC and invalidate any function analysis 778 // results that might have outer dependencies on an SCC analysis. 779 for (LazyCallGraph::Node &N : C) { 780 Function &F = N.getFunction(); 781 782 auto *OuterProxy = 783 FAM.getCachedResult<CGSCCAnalysisManagerFunctionProxy>(F); 784 if (!OuterProxy) 785 // No outer analyses were queried, nothing to do. 786 continue; 787 788 // Forcibly abandon all the inner analyses with dependencies, but 789 // invalidate nothing else. 790 auto PA = PreservedAnalyses::all(); 791 for (const auto &OuterInvalidationPair : 792 OuterProxy->getOuterInvalidations()) { 793 const auto &InnerAnalysisIDs = OuterInvalidationPair.second; 794 for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs) 795 PA.abandon(InnerAnalysisID); 796 } 797 798 // Now invalidate anything we found. 799 FAM.invalidate(F, PA); 800 } 801 } 802 803 /// Helper function to update both the \c CGSCCAnalysisManager \p AM and the \c 804 /// CGSCCPassManager's \c CGSCCUpdateResult \p UR based on a range of newly 805 /// added SCCs. 806 /// 807 /// The range of new SCCs must be in postorder already. The SCC they were split 808 /// out of must be provided as \p C. The current node being mutated and 809 /// triggering updates must be passed as \p N. 810 /// 811 /// This function returns the SCC containing \p N. This will be either \p C if 812 /// no new SCCs have been split out, or it will be the new SCC containing \p N. 813 template <typename SCCRangeT> 814 static LazyCallGraph::SCC * 815 incorporateNewSCCRange(const SCCRangeT &NewSCCRange, LazyCallGraph &G, 816 LazyCallGraph::Node &N, LazyCallGraph::SCC *C, 817 CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR) { 818 using SCC = LazyCallGraph::SCC; 819 820 if (NewSCCRange.empty()) 821 return C; 822 823 // Add the current SCC to the worklist as its shape has changed. 824 UR.CWorklist.insert(C); 825 LLVM_DEBUG(dbgs() << "Enqueuing the existing SCC in the worklist:" << *C 826 << "\n"); 827 828 SCC *OldC = C; 829 830 // Update the current SCC. Note that if we have new SCCs, this must actually 831 // change the SCC. 832 assert(C != &*NewSCCRange.begin() && 833 "Cannot insert new SCCs without changing current SCC!"); 834 C = &*NewSCCRange.begin(); 835 assert(G.lookupSCC(N) == C && "Failed to update current SCC!"); 836 837 // If we had a cached FAM proxy originally, we will want to create more of 838 // them for each SCC that was split off. 839 FunctionAnalysisManager *FAM = nullptr; 840 if (auto *FAMProxy = 841 AM.getCachedResult<FunctionAnalysisManagerCGSCCProxy>(*OldC)) 842 FAM = &FAMProxy->getManager(); 843 844 // We need to propagate an invalidation call to all but the newly current SCC 845 // because the outer pass manager won't do that for us after splitting them. 846 // FIXME: We should accept a PreservedAnalysis from the CG updater so that if 847 // there are preserved analysis we can avoid invalidating them here for 848 // split-off SCCs. 849 // We know however that this will preserve any FAM proxy so go ahead and mark 850 // that. 851 auto PA = PreservedAnalyses::allInSet<AllAnalysesOn<Function>>(); 852 PA.preserve<FunctionAnalysisManagerCGSCCProxy>(); 853 AM.invalidate(*OldC, PA); 854 855 // Ensure the now-current SCC's function analyses are updated. 856 if (FAM) 857 updateNewSCCFunctionAnalyses(*C, G, AM, *FAM); 858 859 for (SCC &NewC : llvm::reverse(llvm::drop_begin(NewSCCRange))) { 860 assert(C != &NewC && "No need to re-visit the current SCC!"); 861 assert(OldC != &NewC && "Already handled the original SCC!"); 862 UR.CWorklist.insert(&NewC); 863 LLVM_DEBUG(dbgs() << "Enqueuing a newly formed SCC:" << NewC << "\n"); 864 865 // Ensure new SCCs' function analyses are updated. 866 if (FAM) 867 updateNewSCCFunctionAnalyses(NewC, G, AM, *FAM); 868 869 // Also propagate a normal invalidation to the new SCC as only the current 870 // will get one from the pass manager infrastructure. 871 AM.invalidate(NewC, PA); 872 } 873 return C; 874 } 875 876 static LazyCallGraph::SCC &updateCGAndAnalysisManagerForPass( 877 LazyCallGraph &G, LazyCallGraph::SCC &InitialC, LazyCallGraph::Node &N, 878 CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR, 879 FunctionAnalysisManager &FAM, bool FunctionPass) { 880 using Node = LazyCallGraph::Node; 881 using Edge = LazyCallGraph::Edge; 882 using SCC = LazyCallGraph::SCC; 883 using RefSCC = LazyCallGraph::RefSCC; 884 885 RefSCC &InitialRC = InitialC.getOuterRefSCC(); 886 SCC *C = &InitialC; 887 RefSCC *RC = &InitialRC; 888 Function &F = N.getFunction(); 889 890 // Walk the function body and build up the set of retained, promoted, and 891 // demoted edges. 892 SmallVector<Constant *, 16> Worklist; 893 SmallPtrSet<Constant *, 16> Visited; 894 SmallPtrSet<Node *, 16> RetainedEdges; 895 SmallSetVector<Node *, 4> PromotedRefTargets; 896 SmallSetVector<Node *, 4> DemotedCallTargets; 897 SmallSetVector<Node *, 4> NewCallEdges; 898 SmallSetVector<Node *, 4> NewRefEdges; 899 900 // First walk the function and handle all called functions. We do this first 901 // because if there is a single call edge, whether there are ref edges is 902 // irrelevant. 903 for (Instruction &I : instructions(F)) { 904 if (auto *CB = dyn_cast<CallBase>(&I)) { 905 if (Function *Callee = CB->getCalledFunction()) { 906 if (Visited.insert(Callee).second && !Callee->isDeclaration()) { 907 Node *CalleeN = G.lookup(*Callee); 908 assert(CalleeN && 909 "Visited function should already have an associated node"); 910 Edge *E = N->lookup(*CalleeN); 911 assert((E || !FunctionPass) && 912 "No function transformations should introduce *new* " 913 "call edges! Any new calls should be modeled as " 914 "promoted existing ref edges!"); 915 bool Inserted = RetainedEdges.insert(CalleeN).second; 916 (void)Inserted; 917 assert(Inserted && "We should never visit a function twice."); 918 if (!E) 919 NewCallEdges.insert(CalleeN); 920 else if (!E->isCall()) 921 PromotedRefTargets.insert(CalleeN); 922 } 923 } else { 924 // We can miss devirtualization if an indirect call is created then 925 // promoted before updateCGAndAnalysisManagerForPass runs. 926 auto *Entry = UR.IndirectVHs.find(CB); 927 if (Entry == UR.IndirectVHs.end()) 928 UR.IndirectVHs.insert({CB, WeakTrackingVH(CB)}); 929 else if (!Entry->second) 930 Entry->second = WeakTrackingVH(CB); 931 } 932 } 933 } 934 935 // Now walk all references. 936 for (Instruction &I : instructions(F)) 937 for (Value *Op : I.operand_values()) 938 if (auto *OpC = dyn_cast<Constant>(Op)) 939 if (Visited.insert(OpC).second) 940 Worklist.push_back(OpC); 941 942 auto VisitRef = [&](Function &Referee) { 943 Node *RefereeN = G.lookup(Referee); 944 assert(RefereeN && 945 "Visited function should already have an associated node"); 946 Edge *E = N->lookup(*RefereeN); 947 assert((E || !FunctionPass) && 948 "No function transformations should introduce *new* ref " 949 "edges! Any new ref edges would require IPO which " 950 "function passes aren't allowed to do!"); 951 bool Inserted = RetainedEdges.insert(RefereeN).second; 952 (void)Inserted; 953 assert(Inserted && "We should never visit a function twice."); 954 if (!E) 955 NewRefEdges.insert(RefereeN); 956 else if (E->isCall()) 957 DemotedCallTargets.insert(RefereeN); 958 }; 959 LazyCallGraph::visitReferences(Worklist, Visited, VisitRef); 960 961 // Handle new ref edges. 962 for (Node *RefTarget : NewRefEdges) { 963 SCC &TargetC = *G.lookupSCC(*RefTarget); 964 RefSCC &TargetRC = TargetC.getOuterRefSCC(); 965 (void)TargetRC; 966 // TODO: This only allows trivial edges to be added for now. 967 #ifdef EXPENSIVE_CHECKS 968 assert((RC == &TargetRC || 969 RC->isAncestorOf(TargetRC)) && "New ref edge is not trivial!"); 970 #endif 971 RC->insertTrivialRefEdge(N, *RefTarget); 972 } 973 974 // Handle new call edges. 975 for (Node *CallTarget : NewCallEdges) { 976 SCC &TargetC = *G.lookupSCC(*CallTarget); 977 RefSCC &TargetRC = TargetC.getOuterRefSCC(); 978 (void)TargetRC; 979 // TODO: This only allows trivial edges to be added for now. 980 #ifdef EXPENSIVE_CHECKS 981 assert((RC == &TargetRC || 982 RC->isAncestorOf(TargetRC)) && "New call edge is not trivial!"); 983 #endif 984 // Add a trivial ref edge to be promoted later on alongside 985 // PromotedRefTargets. 986 RC->insertTrivialRefEdge(N, *CallTarget); 987 } 988 989 // Include synthetic reference edges to known, defined lib functions. 990 for (auto *LibFn : G.getLibFunctions()) 991 // While the list of lib functions doesn't have repeats, don't re-visit 992 // anything handled above. 993 if (!Visited.count(LibFn)) 994 VisitRef(*LibFn); 995 996 // First remove all of the edges that are no longer present in this function. 997 // The first step makes these edges uniformly ref edges and accumulates them 998 // into a separate data structure so removal doesn't invalidate anything. 999 SmallVector<Node *, 4> DeadTargets; 1000 for (Edge &E : *N) { 1001 if (RetainedEdges.count(&E.getNode())) 1002 continue; 1003 1004 SCC &TargetC = *G.lookupSCC(E.getNode()); 1005 RefSCC &TargetRC = TargetC.getOuterRefSCC(); 1006 if (&TargetRC == RC && E.isCall()) { 1007 if (C != &TargetC) { 1008 // For separate SCCs this is trivial. 1009 RC->switchTrivialInternalEdgeToRef(N, E.getNode()); 1010 } else { 1011 // Now update the call graph. 1012 C = incorporateNewSCCRange(RC->switchInternalEdgeToRef(N, E.getNode()), 1013 G, N, C, AM, UR); 1014 } 1015 } 1016 1017 // Now that this is ready for actual removal, put it into our list. 1018 DeadTargets.push_back(&E.getNode()); 1019 } 1020 // Remove the easy cases quickly and actually pull them out of our list. 1021 llvm::erase_if(DeadTargets, [&](Node *TargetN) { 1022 SCC &TargetC = *G.lookupSCC(*TargetN); 1023 RefSCC &TargetRC = TargetC.getOuterRefSCC(); 1024 1025 // We can't trivially remove internal targets, so skip 1026 // those. 1027 if (&TargetRC == RC) 1028 return false; 1029 1030 LLVM_DEBUG(dbgs() << "Deleting outgoing edge from '" << N << "' to '" 1031 << *TargetN << "'\n"); 1032 RC->removeOutgoingEdge(N, *TargetN); 1033 return true; 1034 }); 1035 1036 // Next demote all the call edges that are now ref edges. This helps make 1037 // the SCCs small which should minimize the work below as we don't want to 1038 // form cycles that this would break. 1039 for (Node *RefTarget : DemotedCallTargets) { 1040 SCC &TargetC = *G.lookupSCC(*RefTarget); 1041 RefSCC &TargetRC = TargetC.getOuterRefSCC(); 1042 1043 // The easy case is when the target RefSCC is not this RefSCC. This is 1044 // only supported when the target RefSCC is a child of this RefSCC. 1045 if (&TargetRC != RC) { 1046 #ifdef EXPENSIVE_CHECKS 1047 assert(RC->isAncestorOf(TargetRC) && 1048 "Cannot potentially form RefSCC cycles here!"); 1049 #endif 1050 RC->switchOutgoingEdgeToRef(N, *RefTarget); 1051 LLVM_DEBUG(dbgs() << "Switch outgoing call edge to a ref edge from '" << N 1052 << "' to '" << *RefTarget << "'\n"); 1053 continue; 1054 } 1055 1056 // We are switching an internal call edge to a ref edge. This may split up 1057 // some SCCs. 1058 if (C != &TargetC) { 1059 // For separate SCCs this is trivial. 1060 RC->switchTrivialInternalEdgeToRef(N, *RefTarget); 1061 continue; 1062 } 1063 1064 // Now update the call graph. 1065 C = incorporateNewSCCRange(RC->switchInternalEdgeToRef(N, *RefTarget), G, N, 1066 C, AM, UR); 1067 } 1068 1069 // We added a ref edge earlier for new call edges, promote those to call edges 1070 // alongside PromotedRefTargets. 1071 for (Node *E : NewCallEdges) 1072 PromotedRefTargets.insert(E); 1073 1074 // Now promote ref edges into call edges. 1075 for (Node *CallTarget : PromotedRefTargets) { 1076 SCC &TargetC = *G.lookupSCC(*CallTarget); 1077 RefSCC &TargetRC = TargetC.getOuterRefSCC(); 1078 1079 // The easy case is when the target RefSCC is not this RefSCC. This is 1080 // only supported when the target RefSCC is a child of this RefSCC. 1081 if (&TargetRC != RC) { 1082 #ifdef EXPENSIVE_CHECKS 1083 assert(RC->isAncestorOf(TargetRC) && 1084 "Cannot potentially form RefSCC cycles here!"); 1085 #endif 1086 RC->switchOutgoingEdgeToCall(N, *CallTarget); 1087 LLVM_DEBUG(dbgs() << "Switch outgoing ref edge to a call edge from '" << N 1088 << "' to '" << *CallTarget << "'\n"); 1089 continue; 1090 } 1091 LLVM_DEBUG(dbgs() << "Switch an internal ref edge to a call edge from '" 1092 << N << "' to '" << *CallTarget << "'\n"); 1093 1094 // Otherwise we are switching an internal ref edge to a call edge. This 1095 // may merge away some SCCs, and we add those to the UpdateResult. We also 1096 // need to make sure to update the worklist in the event SCCs have moved 1097 // before the current one in the post-order sequence 1098 bool HasFunctionAnalysisProxy = false; 1099 auto InitialSCCIndex = RC->find(*C) - RC->begin(); 1100 bool FormedCycle = RC->switchInternalEdgeToCall( 1101 N, *CallTarget, [&](ArrayRef<SCC *> MergedSCCs) { 1102 for (SCC *MergedC : MergedSCCs) { 1103 assert(MergedC != &TargetC && "Cannot merge away the target SCC!"); 1104 1105 HasFunctionAnalysisProxy |= 1106 AM.getCachedResult<FunctionAnalysisManagerCGSCCProxy>( 1107 *MergedC) != nullptr; 1108 1109 // Mark that this SCC will no longer be valid. 1110 UR.InvalidatedSCCs.insert(MergedC); 1111 1112 // FIXME: We should really do a 'clear' here to forcibly release 1113 // memory, but we don't have a good way of doing that and 1114 // preserving the function analyses. 1115 auto PA = PreservedAnalyses::allInSet<AllAnalysesOn<Function>>(); 1116 PA.preserve<FunctionAnalysisManagerCGSCCProxy>(); 1117 AM.invalidate(*MergedC, PA); 1118 } 1119 }); 1120 1121 // If we formed a cycle by creating this call, we need to update more data 1122 // structures. 1123 if (FormedCycle) { 1124 C = &TargetC; 1125 assert(G.lookupSCC(N) == C && "Failed to update current SCC!"); 1126 1127 // If one of the invalidated SCCs had a cached proxy to a function 1128 // analysis manager, we need to create a proxy in the new current SCC as 1129 // the invalidated SCCs had their functions moved. 1130 if (HasFunctionAnalysisProxy) 1131 AM.getResult<FunctionAnalysisManagerCGSCCProxy>(*C, G).updateFAM(FAM); 1132 1133 // Any analyses cached for this SCC are no longer precise as the shape 1134 // has changed by introducing this cycle. However, we have taken care to 1135 // update the proxies so it remains valide. 1136 auto PA = PreservedAnalyses::allInSet<AllAnalysesOn<Function>>(); 1137 PA.preserve<FunctionAnalysisManagerCGSCCProxy>(); 1138 AM.invalidate(*C, PA); 1139 } 1140 auto NewSCCIndex = RC->find(*C) - RC->begin(); 1141 // If we have actually moved an SCC to be topologically "below" the current 1142 // one due to merging, we will need to revisit the current SCC after 1143 // visiting those moved SCCs. 1144 // 1145 // It is critical that we *do not* revisit the current SCC unless we 1146 // actually move SCCs in the process of merging because otherwise we may 1147 // form a cycle where an SCC is split apart, merged, split, merged and so 1148 // on infinitely. 1149 if (InitialSCCIndex < NewSCCIndex) { 1150 // Put our current SCC back onto the worklist as we'll visit other SCCs 1151 // that are now definitively ordered prior to the current one in the 1152 // post-order sequence, and may end up observing more precise context to 1153 // optimize the current SCC. 1154 UR.CWorklist.insert(C); 1155 LLVM_DEBUG(dbgs() << "Enqueuing the existing SCC in the worklist: " << *C 1156 << "\n"); 1157 // Enqueue in reverse order as we pop off the back of the worklist. 1158 for (SCC &MovedC : llvm::reverse(make_range(RC->begin() + InitialSCCIndex, 1159 RC->begin() + NewSCCIndex))) { 1160 UR.CWorklist.insert(&MovedC); 1161 LLVM_DEBUG(dbgs() << "Enqueuing a newly earlier in post-order SCC: " 1162 << MovedC << "\n"); 1163 } 1164 } 1165 } 1166 1167 assert(!UR.InvalidatedSCCs.count(C) && "Invalidated the current SCC!"); 1168 assert(&C->getOuterRefSCC() == RC && "Current SCC not in current RefSCC!"); 1169 1170 // Record the current SCC for higher layers of the CGSCC pass manager now that 1171 // all the updates have been applied. 1172 if (C != &InitialC) 1173 UR.UpdatedC = C; 1174 1175 return *C; 1176 } 1177 1178 LazyCallGraph::SCC &llvm::updateCGAndAnalysisManagerForFunctionPass( 1179 LazyCallGraph &G, LazyCallGraph::SCC &InitialC, LazyCallGraph::Node &N, 1180 CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR, 1181 FunctionAnalysisManager &FAM) { 1182 return updateCGAndAnalysisManagerForPass(G, InitialC, N, AM, UR, FAM, 1183 /* FunctionPass */ true); 1184 } 1185 LazyCallGraph::SCC &llvm::updateCGAndAnalysisManagerForCGSCCPass( 1186 LazyCallGraph &G, LazyCallGraph::SCC &InitialC, LazyCallGraph::Node &N, 1187 CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR, 1188 FunctionAnalysisManager &FAM) { 1189 return updateCGAndAnalysisManagerForPass(G, InitialC, N, AM, UR, FAM, 1190 /* FunctionPass */ false); 1191 } 1192