llvm-project/llvm/lib/Transforms/Scalar/LoopPassManager.cpp
Andrew Monshizadeh c5a06019d2 Extend TimeTrace to LLVM's new pass manager
With the addition of the LLD time tracing it made sense to include coverage
for LLVM's various passes. Doing so ensures that ThinLTO is also covered
with a time trace.

Before:
{F11333974}

After:
{F11333928}

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D74516
2020-03-06 14:45:19 -08:00

111 lines
4.0 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/Support/TimeProfiler.h"
#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;
{
TimeTraceScope TimeScope(Pass->name(), L.getName());
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();
}