lib/Analysis/RegionInfo.cpp

   1 //===- RegionInfo.cpp - SESE region detection analysis --------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 // Detects single entry single exit regions in the control flow graph.
  10 //===----------------------------------------------------------------------===//
  11
  12 #include "llvm/Analysis/RegionInfo.h"
  13 #include "llvm/ADT/PostOrderIterator.h"
  14 #include "llvm/ADT/Statistic.h"
  15 #include "llvm/Analysis/LoopInfo.h"
  16 #include "llvm/Analysis/RegionInfoImpl.h"
  17 #include "llvm/Analysis/RegionIterator.h"
  18 #include "llvm/Support/CommandLine.h"
  19 #include "llvm/Support/Debug.h"
  20 #include "llvm/Support/ErrorHandling.h"
  21 #include <algorithm>
  22 #include <iterator>
  23 #include <set>
  24 #ifndef NDEBUG
  25 #include "llvm/Analysis/RegionPrinter.h"
  26 #endif
  27
  28 using namespace llvm;
  29
  30 #define DEBUG_TYPE "region"
  31
  32 namespace llvm {
  33 template class RegionBase<RegionTraits<Function>>;
  34 template class RegionNodeBase<RegionTraits<Function>>;
  35 template class RegionInfoBase<RegionTraits<Function>>;
  36 }
  37
  38 STATISTIC(numRegions,       "The # of regions");
  39 STATISTIC(numSimpleRegions, "The # of simple regions");
  40
  41 // Always verify if expensive checking is enabled.
  42
  43 static cl::opt<bool,true>
  44 VerifyRegionInfoX(
  45   "verify-region-info",
  46   cl::location(RegionInfoBase<RegionTraits<Function>>::VerifyRegionInfo),
  47   cl::desc("Verify region info (time consuming)"));
  48
  49
  50 static cl::opt<Region::PrintStyle, true> printStyleX("print-region-style",
  51   cl::location(RegionInfo::printStyle),
  52   cl::Hidden,
  53   cl::desc("style of printing regions"),
  54   cl::values(
  55     clEnumValN(Region::PrintNone, "none",  "print no details"),
  56     clEnumValN(Region::PrintBB, "bb",
  57                "print regions in detail with block_iterator"),
  58     clEnumValN(Region::PrintRN, "rn",
  59                "print regions in detail with element_iterator"),
  60     clEnumValEnd));
  61
  62
  63 //===----------------------------------------------------------------------===//
  64 // Region implementation
  65 //
  66
  67 Region::Region(BasicBlock *Entry, BasicBlock *Exit,
  68                RegionInfo* RI,
  69                DominatorTree *DT, Region *Parent) :
  70   RegionBase<RegionTraits<Function>>(Entry, Exit, RI, DT, Parent) {
  71
  72 }
  73
  74 Region::~Region() { }
  75
  76 //===----------------------------------------------------------------------===//
  77 // RegionInfo implementation
  78 //
  79
  80 RegionInfo::RegionInfo() :
  81   RegionInfoBase<RegionTraits<Function>>() {
  82
  83 }
  84
  85 RegionInfo::~RegionInfo() {
  86
  87 }
  88
  89 void RegionInfo::updateStatistics(Region *R) {
  90   ++numRegions;
  91
  92   // TODO: Slow. Should only be enabled if -stats is used.
  93   if (R->isSimple())
  94     ++numSimpleRegions;
  95 }
  96
  97 void RegionInfo::recalculate(Function &F, DominatorTree *DT_,
  98                              PostDominatorTree *PDT_, DominanceFrontier *DF_) {
  99   DT = DT_;
 100   PDT = PDT_;
 101   DF = DF_;
 102
 103   TopLevelRegion = new Region(&F.getEntryBlock(), nullptr,
 104                               this, DT, nullptr);
 105   updateStatistics(TopLevelRegion);
 106   calculate(F);
 107 }
 108
 109 #ifndef NDEBUG
 110 void RegionInfo::view() { viewRegion(this); }
 111
 112 void RegionInfo::viewOnly() { viewRegionOnly(this); }
 113 #endif
 114
 115 //===----------------------------------------------------------------------===//
 116 // RegionInfoPass implementation
 117 //
 118
 119 RegionInfoPass::RegionInfoPass() : FunctionPass(ID) {
 120   initializeRegionInfoPassPass(*PassRegistry::getPassRegistry());
 121 }
 122
 123 RegionInfoPass::~RegionInfoPass() {
 124
 125 }
 126
 127 bool RegionInfoPass::runOnFunction(Function &F) {
 128   releaseMemory();
 129
 130   auto DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
 131   auto PDT = &getAnalysis<PostDominatorTree>();
 132   auto DF = &getAnalysis<DominanceFrontier>();
 133
 134   RI.recalculate(F, DT, PDT, DF);
 135   return false;
 136 }
 137
 138 void RegionInfoPass::releaseMemory() {
 139   RI.releaseMemory();
 140 }
 141
 142 void RegionInfoPass::verifyAnalysis() const {
 143     RI.verifyAnalysis();
 144 }
 145
 146 void RegionInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
 147   AU.setPreservesAll();
 148   AU.addRequiredTransitive<DominatorTreeWrapperPass>();
 149   AU.addRequired<PostDominatorTree>();
 150   AU.addRequired<DominanceFrontier>();
 151 }
 152
 153 void RegionInfoPass::print(raw_ostream &OS, const Module *) const {
 154   RI.print(OS);
 155 }
 156
 157 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 158 void RegionInfoPass::dump() const {
 159   RI.dump();
 160 }
 161 #endif
 162
 163 char RegionInfoPass::ID = 0;
 164
 165 INITIALIZE_PASS_BEGIN(RegionInfoPass, "regions",
 166                 "Detect single entry single exit regions", true, true)
 167 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 168 INITIALIZE_PASS_DEPENDENCY(PostDominatorTree)
 169 INITIALIZE_PASS_DEPENDENCY(DominanceFrontier)
 170 INITIALIZE_PASS_END(RegionInfoPass, "regions",
 171                 "Detect single entry single exit regions", true, true)
 172
 173 // Create methods available outside of this file, to use them
 174 // "include/llvm/LinkAllPasses.h". Otherwise the pass would be deleted by
 175 // the link time optimization.
 176
 177 namespace llvm {
 178   FunctionPass *createRegionInfoPass() {
 179     return new RegionInfoPass();
 180   }
 181 }
 182