1 //===- LoopPassManager.cpp - Loop pass management -------------------------===// 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 #include "llvm/Transforms/Scalar/LoopPassManager.h" 11 #include "llvm/Analysis/LoopInfo.h" 12 13 using namespace llvm; 14 15 // Explicit template instantiations and specialization defininitions for core 16 // template typedefs. 17 namespace llvm { 18 template class PassManager<Loop, LoopAnalysisManager, 19 LoopStandardAnalysisResults &, LPMUpdater &>; 20 21 /// Explicitly specialize the pass manager's run method to handle loop nest 22 /// structure updates. 23 template <> 24 PreservedAnalyses 25 PassManager<Loop, LoopAnalysisManager, LoopStandardAnalysisResults &, 26 LPMUpdater &>::run(Loop &L, LoopAnalysisManager &AM, 27 LoopStandardAnalysisResults &AR, LPMUpdater &U) { 28 PreservedAnalyses PA = PreservedAnalyses::all(); 29 30 if (DebugLogging) 31 dbgs() << "Starting Loop pass manager run.\n"; 32 33 // Request PassInstrumentation from analysis manager, will use it to run 34 // instrumenting callbacks for the passes later. 35 PassInstrumentation PI = AM.getResult<PassInstrumentationAnalysis>(L, AR); 36 for (auto &Pass : Passes) { 37 if (DebugLogging) 38 dbgs() << "Running pass: " << Pass->name() << " on " << L; 39 40 // Check the PassInstrumentation's BeforePass callbacks before running the 41 // pass, skip its execution completely if asked to (callback returns false). 42 if (!PI.runBeforePass<Loop>(*Pass, L)) 43 continue; 44 45 PreservedAnalyses PassPA = Pass->run(L, AM, AR, U); 46 47 PI.runAfterPass<Loop>(*Pass, L); 48 49 // If the loop was deleted, abort the run and return to the outer walk. 50 if (U.skipCurrentLoop()) { 51 PA.intersect(std::move(PassPA)); 52 break; 53 } 54 55 #ifndef NDEBUG 56 // Verify the loop structure and LCSSA form before visiting the loop. 57 L.verifyLoop(); 58 assert(L.isRecursivelyLCSSAForm(AR.DT, AR.LI) && 59 "Loops must remain in LCSSA form!"); 60 #endif 61 62 // Update the analysis manager as each pass runs and potentially 63 // invalidates analyses. 64 AM.invalidate(L, PassPA); 65 66 // Finally, we intersect the final preserved analyses to compute the 67 // aggregate preserved set for this pass manager. 68 PA.intersect(std::move(PassPA)); 69 70 // FIXME: Historically, the pass managers all called the LLVM context's 71 // yield function here. We don't have a generic way to acquire the 72 // context and it isn't yet clear what the right pattern is for yielding 73 // in the new pass manager so it is currently omitted. 74 // ...getContext().yield(); 75 } 76 77 // Invalidation for the current loop should be handled above, and other loop 78 // analysis results shouldn't be impacted by runs over this loop. Therefore, 79 // the remaining analysis results in the AnalysisManager are preserved. We 80 // mark this with a set so that we don't need to inspect each one 81 // individually. 82 // FIXME: This isn't correct! This loop and all nested loops' analyses should 83 // be preserved, but unrolling should invalidate the parent loop's analyses. 84 PA.preserveSet<AllAnalysesOn<Loop>>(); 85 86 if (DebugLogging) 87 dbgs() << "Finished Loop pass manager run.\n"; 88 89 return PA; 90 } 91 } 92 93 PrintLoopPass::PrintLoopPass() : OS(dbgs()) {} 94 PrintLoopPass::PrintLoopPass(raw_ostream &OS, const std::string &Banner) 95 : OS(OS), Banner(Banner) {} 96 97 PreservedAnalyses PrintLoopPass::run(Loop &L, LoopAnalysisManager &, 98 LoopStandardAnalysisResults &, 99 LPMUpdater &) { 100 printLoop(L, OS, Banner); 101 return PreservedAnalyses::all(); 102 } 103