[llvm-branch-commits] [polly] [Polly] Introduce PhaseManager and remove LPM support (PR #125442)

[Karthika Devi C via llvm-branch-commits]

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+//===------ PhaseManager.cpp ------------------------------------*- C++ -*-===//
+//
+// 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 "polly/Pass/PhaseManager.h"
+#include "polly/CodeGen/CodeGeneration.h"
+#include "polly/CodeGen/IslAst.h"
+#include "polly/CodePreparation.h"
+#include "polly/DeLICM.h"
+#include "polly/DeadCodeElimination.h"
+#include "polly/DependenceInfo.h"
+#include "polly/FlattenSchedule.h"
+#include "polly/ForwardOpTree.h"
+#include "polly/JSONExporter.h"
+#include "polly/MaximalStaticExpansion.h"
+#include "polly/PruneUnprofitable.h"
+#include "polly/ScheduleOptimizer.h"
+#include "polly/ScopDetection.h"
+#include "polly/ScopDetectionDiagnostic.h"
+#include "polly/ScopGraphPrinter.h"
+#include "polly/ScopInfo.h"
+#include "polly/Simplify.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/OptimizationRemarkEmitter.h"
+#include "llvm/IR/Module.h"
+
+#define DEBUG_TYPE "polly-pass"
+
+using namespace polly;
+using namespace llvm;
+
+namespace {
+
+/// Recurse through all subregions and all regions and add them to RQ.
+static void addRegionIntoQueue(Region &R, SmallVector<Region *> &RQ) {
+  RQ.push_back(&R);
+  for (const auto &E : R)
+    addRegionIntoQueue(*E, RQ);
+}
+
+/// The phase pipeline of Polly to be embedded into another pass manager than
+/// runs passes on functions.
+///
+/// Polly holds state besides LLVM-IR (RegionInfo and ScopInfo) between phases
+/// that LLVM pass managers do not consider when scheduling analyses and passes.
+/// That is, the ScopInfo must persist between phases that a pass manager must
+/// not invalidate to recompute later.
+class PhaseManager {
+private:
+  Function &F;
+  FunctionAnalysisManager &FAM;
+  PollyPassOptions Opts;
+
+public:
+  PhaseManager(Function &F, FunctionAnalysisManager &FAM, PollyPassOptions Opts)
+      : F(F), FAM(FAM), Opts(std::move(Opts)) {}
+
+  /// Execute Polly's phases as indicated by the options.
+  bool run() {
+    // Get analyses from the function pass manager.
+    // These must be preserved during all phases so that if processing one SCoP
+    // has finished, the next SCoP can still use them. Recomputing is not an
+    // option because ScopDetection stores references to the old results.
+    // TODO: CodePreparation doesn't actually need these analysis, it just keeps
+    // them up-to-date. If they are not computed yet, can also compute after the
+    // prepare phase.
+    auto &LI = FAM.getResult<LoopAnalysis>(F);
+    auto &DT = FAM.getResult<DominatorTreeAnalysis>(F);
+    bool ModifiedIR = false;
+
+    // Phase: prepare
+    // TODO: Setting ModifiedIR will invalidate any anlysis, even if DT, LI are
+    // preserved.
+    if (Opts.isPhaseEnabled(PassPhase::Prepare))
+      ModifiedIR |= runCodePreparation(F, &DT, &LI, nullptr);
+
+    // Can't do anything without detection
+    if (!Opts.isPhaseEnabled(PassPhase::Detection))
+      return false;
+
+    auto &AA = FAM.getResult<AAManager>(F);
+    auto &SE = FAM.getResult<ScalarEvolutionAnalysis>(F);
+    auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(F);
+
+    // ScopDetection is modifying RegionInfo, do not cache it, nor use a cached
+    // version.
+    RegionInfo RI = RegionInfoAnalysis().run(F, FAM);
+
+    // Phase: detection
+    ScopDetection SD(DT, SE, LI, RI, AA, ORE);
+    SD.detect(F);
+    if (Opts.isPhaseEnabled(PassPhase::PrintDetect)) {
+      outs() << "Detected Scops in Function " << F.getName() << "\n";
+      for (const Region *R : SD.ValidRegions)
+        outs() << "Valid Region for Scop: " << R->getNameStr() << '\n';
+      outs() << "\n";
+    }
+
+    if (Opts.isPhaseEnabled(PassPhase::DotScops))
+      printGraphForFunction(F, &SD, "scops", false);
+    if (Opts.isPhaseEnabled(PassPhase::DotScopsOnly))
+      printGraphForFunction(F, &SD, "scopsonly", true);
+
+    auto ViewScops = [&](const char *Name, bool IsSimply) {
+      if (Opts.ViewFilter.empty() && !F.getName().count(Opts.ViewFilter))
+        return;
+
+      if (Opts.ViewAll || std::distance(SD.begin(), SD.end()) > 0)
+        viewGraphForFunction(F, &SD, Name, IsSimply);
+    };
+    if (Opts.isPhaseEnabled(PassPhase::ViewScops))
+      ViewScops("scops", false);
+    if (Opts.isPhaseEnabled(PassPhase::ViewScopsOnly))
+      ViewScops("scopsonly", true);
+
+    // Phase: scops
+    auto &AC = FAM.getResult<AssumptionAnalysis>(F);
+    const DataLayout &DL = F.getParent()->getDataLayout();
+    ScopInfo Info(DL, SD, SE, LI, AA, DT, AC, ORE);
----------------
kartcq wrote:

This way of computing ScopInfo processes the regions in same order, as opposed to reverse order, followed by FunctionToScopPassAdaptor earlier.
To pertain to this, can we either invoke ScopBuilder in reverse order here or change the order in ScopInfo::recompute.

https://github.com/llvm/llvm-project/pull/125442