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