1 //===- LoopPassManager.cpp - Loop pass management -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/Transforms/Scalar/LoopPassManager.h"
11 #include "llvm/Analysis/LoopInfo.h"
15 // Explicit template instantiations and specialization defininitions for core
18 template class PassManager<Loop, LoopAnalysisManager,
19 LoopStandardAnalysisResults &, LPMUpdater &>;
21 /// Explicitly specialize the pass manager's run method to handle loop nest
22 /// structure updates.
25 PassManager<Loop, LoopAnalysisManager, LoopStandardAnalysisResults &,
26 LPMUpdater &>::run(Loop &L, LoopAnalysisManager &AM,
27 LoopStandardAnalysisResults &AR, LPMUpdater &U) {
28 PreservedAnalyses PA = PreservedAnalyses::all();
31 dbgs() << "Starting Loop pass manager run.\n";
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) {
38 dbgs() << "Running pass: " << Pass->name() << " on " << L;
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))
45 PreservedAnalyses PassPA = Pass->run(L, AM, AR, U);
47 // do not pass deleted Loop into the instrumentation
48 if (U.skipCurrentLoop())
49 PI.runAfterPassInvalidated<Loop>(*Pass);
51 PI.runAfterPass<Loop>(*Pass, L);
53 // If the loop was deleted, abort the run and return to the outer walk.
54 if (U.skipCurrentLoop()) {
55 PA.intersect(std::move(PassPA));
60 // Verify the loop structure and LCSSA form before visiting the loop.
62 assert(L.isRecursivelyLCSSAForm(AR.DT, AR.LI) &&
63 "Loops must remain in LCSSA form!");
66 // Update the analysis manager as each pass runs and potentially
67 // invalidates analyses.
68 AM.invalidate(L, PassPA);
70 // Finally, we intersect the final preserved analyses to compute the
71 // aggregate preserved set for this pass manager.
72 PA.intersect(std::move(PassPA));
74 // FIXME: Historically, the pass managers all called the LLVM context's
75 // yield function here. We don't have a generic way to acquire the
76 // context and it isn't yet clear what the right pattern is for yielding
77 // in the new pass manager so it is currently omitted.
78 // ...getContext().yield();
81 // Invalidation for the current loop should be handled above, and other loop
82 // analysis results shouldn't be impacted by runs over this loop. Therefore,
83 // the remaining analysis results in the AnalysisManager are preserved. We
84 // mark this with a set so that we don't need to inspect each one
86 // FIXME: This isn't correct! This loop and all nested loops' analyses should
87 // be preserved, but unrolling should invalidate the parent loop's analyses.
88 PA.preserveSet<AllAnalysesOn<Loop>>();
91 dbgs() << "Finished Loop pass manager run.\n";
97 PrintLoopPass::PrintLoopPass() : OS(dbgs()) {}
98 PrintLoopPass::PrintLoopPass(raw_ostream &OS, const std::string &Banner)
99 : OS(OS), Banner(Banner) {}
101 PreservedAnalyses PrintLoopPass::run(Loop &L, LoopAnalysisManager &,
102 LoopStandardAnalysisResults &,
104 printLoop(L, OS, Banner);
105 return PreservedAnalyses::all();