1 //===- LoopPassManager.cpp - Loop pass management -------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 #include "llvm/Transforms/Scalar/LoopPassManager.h"
10 #include "llvm/Analysis/LoopInfo.h"
14 // Explicit template instantiations and specialization defininitions for core
17 template class PassManager
<Loop
, LoopAnalysisManager
,
18 LoopStandardAnalysisResults
&, LPMUpdater
&>;
20 /// Explicitly specialize the pass manager's run method to handle loop nest
21 /// structure updates.
24 PassManager
<Loop
, LoopAnalysisManager
, LoopStandardAnalysisResults
&,
25 LPMUpdater
&>::run(Loop
&L
, LoopAnalysisManager
&AM
,
26 LoopStandardAnalysisResults
&AR
, LPMUpdater
&U
) {
27 PreservedAnalyses PA
= PreservedAnalyses::all();
30 dbgs() << "Starting Loop pass manager run.\n";
32 // Request PassInstrumentation from analysis manager, will use it to run
33 // instrumenting callbacks for the passes later.
34 PassInstrumentation PI
= AM
.getResult
<PassInstrumentationAnalysis
>(L
, AR
);
35 for (auto &Pass
: Passes
) {
37 dbgs() << "Running pass: " << Pass
->name() << " on " << L
;
39 // Check the PassInstrumentation's BeforePass callbacks before running the
40 // pass, skip its execution completely if asked to (callback returns false).
41 if (!PI
.runBeforePass
<Loop
>(*Pass
, L
))
44 PreservedAnalyses PassPA
= Pass
->run(L
, AM
, AR
, U
);
46 // do not pass deleted Loop into the instrumentation
47 if (U
.skipCurrentLoop())
48 PI
.runAfterPassInvalidated
<Loop
>(*Pass
);
50 PI
.runAfterPass
<Loop
>(*Pass
, L
);
52 // If the loop was deleted, abort the run and return to the outer walk.
53 if (U
.skipCurrentLoop()) {
54 PA
.intersect(std::move(PassPA
));
59 // Verify the loop structure and LCSSA form before visiting the loop.
61 assert(L
.isRecursivelyLCSSAForm(AR
.DT
, AR
.LI
) &&
62 "Loops must remain in LCSSA form!");
65 // Update the analysis manager as each pass runs and potentially
66 // invalidates analyses.
67 AM
.invalidate(L
, PassPA
);
69 // Finally, we intersect the final preserved analyses to compute the
70 // aggregate preserved set for this pass manager.
71 PA
.intersect(std::move(PassPA
));
73 // FIXME: Historically, the pass managers all called the LLVM context's
74 // yield function here. We don't have a generic way to acquire the
75 // context and it isn't yet clear what the right pattern is for yielding
76 // in the new pass manager so it is currently omitted.
77 // ...getContext().yield();
80 // Invalidation for the current loop should be handled above, and other loop
81 // analysis results shouldn't be impacted by runs over this loop. Therefore,
82 // the remaining analysis results in the AnalysisManager are preserved. We
83 // mark this with a set so that we don't need to inspect each one
85 // FIXME: This isn't correct! This loop and all nested loops' analyses should
86 // be preserved, but unrolling should invalidate the parent loop's analyses.
87 PA
.preserveSet
<AllAnalysesOn
<Loop
>>();
90 dbgs() << "Finished Loop pass manager run.\n";
96 PrintLoopPass::PrintLoopPass() : OS(dbgs()) {}
97 PrintLoopPass::PrintLoopPass(raw_ostream
&OS
, const std::string
&Banner
)
98 : OS(OS
), Banner(Banner
) {}
100 PreservedAnalyses
PrintLoopPass::run(Loop
&L
, LoopAnalysisManager
&,
101 LoopStandardAnalysisResults
&,
103 printLoop(L
, OS
, Banner
);
104 return PreservedAnalyses::all();