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llvm-mirror/lib/Transforms/Scalar/LoopPassManager.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

106 lines
3.9 KiB
C++

//===- LoopPassManager.cpp - Loop pass management -------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Scalar/LoopPassManager.h"
#include "llvm/Analysis/LoopInfo.h"
using namespace llvm;
// Explicit template instantiations and specialization defininitions for core
// template typedefs.
namespace llvm {
template class PassManager<Loop, LoopAnalysisManager,
LoopStandardAnalysisResults &, LPMUpdater &>;
/// Explicitly specialize the pass manager's run method to handle loop nest
/// structure updates.
template <>
PreservedAnalyses
PassManager<Loop, LoopAnalysisManager, LoopStandardAnalysisResults &,
LPMUpdater &>::run(Loop &L, LoopAnalysisManager &AM,
LoopStandardAnalysisResults &AR, LPMUpdater &U) {
PreservedAnalyses PA = PreservedAnalyses::all();
if (DebugLogging)
dbgs() << "Starting Loop pass manager run.\n";
// Request PassInstrumentation from analysis manager, will use it to run
// instrumenting callbacks for the passes later.
PassInstrumentation PI = AM.getResult<PassInstrumentationAnalysis>(L, AR);
for (auto &Pass : Passes) {
if (DebugLogging)
dbgs() << "Running pass: " << Pass->name() << " on " << L;
// Check the PassInstrumentation's BeforePass callbacks before running the
// pass, skip its execution completely if asked to (callback returns false).
if (!PI.runBeforePass<Loop>(*Pass, L))
continue;
PreservedAnalyses PassPA = Pass->run(L, AM, AR, U);
// do not pass deleted Loop into the instrumentation
if (U.skipCurrentLoop())
PI.runAfterPassInvalidated<Loop>(*Pass);
else
PI.runAfterPass<Loop>(*Pass, L);
// If the loop was deleted, abort the run and return to the outer walk.
if (U.skipCurrentLoop()) {
PA.intersect(std::move(PassPA));
break;
}
#ifndef NDEBUG
// Verify the loop structure and LCSSA form before visiting the loop.
L.verifyLoop();
assert(L.isRecursivelyLCSSAForm(AR.DT, AR.LI) &&
"Loops must remain in LCSSA form!");
#endif
// Update the analysis manager as each pass runs and potentially
// invalidates analyses.
AM.invalidate(L, PassPA);
// Finally, we intersect the final preserved analyses to compute the
// aggregate preserved set for this pass manager.
PA.intersect(std::move(PassPA));
// FIXME: Historically, the pass managers all called the LLVM context's
// yield function here. We don't have a generic way to acquire the
// context and it isn't yet clear what the right pattern is for yielding
// in the new pass manager so it is currently omitted.
// ...getContext().yield();
}
// Invalidation for the current loop should be handled above, and other loop
// analysis results shouldn't be impacted by runs over this loop. Therefore,
// the remaining analysis results in the AnalysisManager are preserved. We
// mark this with a set so that we don't need to inspect each one
// individually.
// FIXME: This isn't correct! This loop and all nested loops' analyses should
// be preserved, but unrolling should invalidate the parent loop's analyses.
PA.preserveSet<AllAnalysesOn<Loop>>();
if (DebugLogging)
dbgs() << "Finished Loop pass manager run.\n";
return PA;
}
}
PrintLoopPass::PrintLoopPass() : OS(dbgs()) {}
PrintLoopPass::PrintLoopPass(raw_ostream &OS, const std::string &Banner)
: OS(OS), Banner(Banner) {}
PreservedAnalyses PrintLoopPass::run(Loop &L, LoopAnalysisManager &,
LoopStandardAnalysisResults &,
LPMUpdater &) {
printLoop(L, OS, Banner);
return PreservedAnalyses::all();
}