| //===- BlockFrequencyInfo.cpp - Block Frequency Analysis ------------------===// | 
 | // | 
 | //                     The LLVM Compiler Infrastructure | 
 | // | 
 | // This file is distributed under the University of Illinois Open Source | 
 | // License. See LICENSE.TXT for details. | 
 | // | 
 | //===----------------------------------------------------------------------===// | 
 | // | 
 | // Loops should be simplified before this analysis. | 
 | // | 
 | //===----------------------------------------------------------------------===// | 
 |  | 
 | #include "llvm/Analysis/BlockFrequencyInfo.h" | 
 | #include "llvm/ADT/APInt.h" | 
 | #include "llvm/ADT/None.h" | 
 | #include "llvm/ADT/iterator.h" | 
 | #include "llvm/Analysis/BlockFrequencyInfoImpl.h" | 
 | #include "llvm/Analysis/BranchProbabilityInfo.h" | 
 | #include "llvm/Analysis/LoopInfo.h" | 
 | #include "llvm/IR/CFG.h" | 
 | #include "llvm/IR/Function.h" | 
 | #include "llvm/IR/PassManager.h" | 
 | #include "llvm/Pass.h" | 
 | #include "llvm/Support/CommandLine.h" | 
 | #include "llvm/Support/GraphWriter.h" | 
 | #include "llvm/Support/raw_ostream.h" | 
 | #include <algorithm> | 
 | #include <cassert> | 
 | #include <string> | 
 |  | 
 | using namespace llvm; | 
 |  | 
 | #define DEBUG_TYPE "block-freq" | 
 |  | 
 | static cl::opt<GVDAGType> ViewBlockFreqPropagationDAG( | 
 |     "view-block-freq-propagation-dags", cl::Hidden, | 
 |     cl::desc("Pop up a window to show a dag displaying how block " | 
 |              "frequencies propagation through the CFG."), | 
 |     cl::values(clEnumValN(GVDT_None, "none", "do not display graphs."), | 
 |                clEnumValN(GVDT_Fraction, "fraction", | 
 |                           "display a graph using the " | 
 |                           "fractional block frequency representation."), | 
 |                clEnumValN(GVDT_Integer, "integer", | 
 |                           "display a graph using the raw " | 
 |                           "integer fractional block frequency representation."), | 
 |                clEnumValN(GVDT_Count, "count", "display a graph using the real " | 
 |                                                "profile count if available."))); | 
 |  | 
 | cl::opt<std::string> | 
 |     ViewBlockFreqFuncName("view-bfi-func-name", cl::Hidden, | 
 |                           cl::desc("The option to specify " | 
 |                                    "the name of the function " | 
 |                                    "whose CFG will be displayed.")); | 
 |  | 
 | cl::opt<unsigned> | 
 |     ViewHotFreqPercent("view-hot-freq-percent", cl::init(10), cl::Hidden, | 
 |                        cl::desc("An integer in percent used to specify " | 
 |                                 "the hot blocks/edges to be displayed " | 
 |                                 "in red: a block or edge whose frequency " | 
 |                                 "is no less than the max frequency of the " | 
 |                                 "function multiplied by this percent.")); | 
 |  | 
 | // Command line option to turn on CFG dot or text dump after profile annotation. | 
 | cl::opt<PGOViewCountsType> PGOViewCounts( | 
 |     "pgo-view-counts", cl::Hidden, | 
 |     cl::desc("A boolean option to show CFG dag or text with " | 
 |              "block profile counts and branch probabilities " | 
 |              "right after PGO profile annotation step. The " | 
 |              "profile counts are computed using branch " | 
 |              "probabilities from the runtime profile data and " | 
 |              "block frequency propagation algorithm. To view " | 
 |              "the raw counts from the profile, use option " | 
 |              "-pgo-view-raw-counts instead. To limit graph " | 
 |              "display to only one function, use filtering option " | 
 |              "-view-bfi-func-name."), | 
 |     cl::values(clEnumValN(PGOVCT_None, "none", "do not show."), | 
 |                clEnumValN(PGOVCT_Graph, "graph", "show a graph."), | 
 |                clEnumValN(PGOVCT_Text, "text", "show in text."))); | 
 |  | 
 | static cl::opt<bool> PrintBlockFreq( | 
 |     "print-bfi", cl::init(false), cl::Hidden, | 
 |     cl::desc("Print the block frequency info.")); | 
 |  | 
 | cl::opt<std::string> PrintBlockFreqFuncName( | 
 |     "print-bfi-func-name", cl::Hidden, | 
 |     cl::desc("The option to specify the name of the function " | 
 |              "whose block frequency info is printed.")); | 
 |  | 
 | namespace llvm { | 
 |  | 
 | static GVDAGType getGVDT() { | 
 |   if (PGOViewCounts == PGOVCT_Graph) | 
 |     return GVDT_Count; | 
 |   return ViewBlockFreqPropagationDAG; | 
 | } | 
 |  | 
 | template <> | 
 | struct GraphTraits<BlockFrequencyInfo *> { | 
 |   using NodeRef = const BasicBlock *; | 
 |   using ChildIteratorType = succ_const_iterator; | 
 |   using nodes_iterator = pointer_iterator<Function::const_iterator>; | 
 |  | 
 |   static NodeRef getEntryNode(const BlockFrequencyInfo *G) { | 
 |     return &G->getFunction()->front(); | 
 |   } | 
 |  | 
 |   static ChildIteratorType child_begin(const NodeRef N) { | 
 |     return succ_begin(N); | 
 |   } | 
 |  | 
 |   static ChildIteratorType child_end(const NodeRef N) { return succ_end(N); } | 
 |  | 
 |   static nodes_iterator nodes_begin(const BlockFrequencyInfo *G) { | 
 |     return nodes_iterator(G->getFunction()->begin()); | 
 |   } | 
 |  | 
 |   static nodes_iterator nodes_end(const BlockFrequencyInfo *G) { | 
 |     return nodes_iterator(G->getFunction()->end()); | 
 |   } | 
 | }; | 
 |  | 
 | using BFIDOTGTraitsBase = | 
 |     BFIDOTGraphTraitsBase<BlockFrequencyInfo, BranchProbabilityInfo>; | 
 |  | 
 | template <> | 
 | struct DOTGraphTraits<BlockFrequencyInfo *> : public BFIDOTGTraitsBase { | 
 |   explicit DOTGraphTraits(bool isSimple = false) | 
 |       : BFIDOTGTraitsBase(isSimple) {} | 
 |  | 
 |   std::string getNodeLabel(const BasicBlock *Node, | 
 |                            const BlockFrequencyInfo *Graph) { | 
 |  | 
 |     return BFIDOTGTraitsBase::getNodeLabel(Node, Graph, getGVDT()); | 
 |   } | 
 |  | 
 |   std::string getNodeAttributes(const BasicBlock *Node, | 
 |                                 const BlockFrequencyInfo *Graph) { | 
 |     return BFIDOTGTraitsBase::getNodeAttributes(Node, Graph, | 
 |                                                 ViewHotFreqPercent); | 
 |   } | 
 |  | 
 |   std::string getEdgeAttributes(const BasicBlock *Node, EdgeIter EI, | 
 |                                 const BlockFrequencyInfo *BFI) { | 
 |     return BFIDOTGTraitsBase::getEdgeAttributes(Node, EI, BFI, BFI->getBPI(), | 
 |                                                 ViewHotFreqPercent); | 
 |   } | 
 | }; | 
 |  | 
 | } // end namespace llvm | 
 |  | 
 | BlockFrequencyInfo::BlockFrequencyInfo() = default; | 
 |  | 
 | BlockFrequencyInfo::BlockFrequencyInfo(const Function &F, | 
 |                                        const BranchProbabilityInfo &BPI, | 
 |                                        const LoopInfo &LI) { | 
 |   calculate(F, BPI, LI); | 
 | } | 
 |  | 
 | BlockFrequencyInfo::BlockFrequencyInfo(BlockFrequencyInfo &&Arg) | 
 |     : BFI(std::move(Arg.BFI)) {} | 
 |  | 
 | BlockFrequencyInfo &BlockFrequencyInfo::operator=(BlockFrequencyInfo &&RHS) { | 
 |   releaseMemory(); | 
 |   BFI = std::move(RHS.BFI); | 
 |   return *this; | 
 | } | 
 |  | 
 | // Explicitly define the default constructor otherwise it would be implicitly | 
 | // defined at the first ODR-use which is the BFI member in the | 
 | // LazyBlockFrequencyInfo header.  The dtor needs the BlockFrequencyInfoImpl | 
 | // template instantiated which is not available in the header. | 
 | BlockFrequencyInfo::~BlockFrequencyInfo() = default; | 
 |  | 
 | bool BlockFrequencyInfo::invalidate(Function &F, const PreservedAnalyses &PA, | 
 |                                     FunctionAnalysisManager::Invalidator &) { | 
 |   // Check whether the analysis, all analyses on functions, or the function's | 
 |   // CFG have been preserved. | 
 |   auto PAC = PA.getChecker<BlockFrequencyAnalysis>(); | 
 |   return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>() || | 
 |            PAC.preservedSet<CFGAnalyses>()); | 
 | } | 
 |  | 
 | void BlockFrequencyInfo::calculate(const Function &F, | 
 |                                    const BranchProbabilityInfo &BPI, | 
 |                                    const LoopInfo &LI) { | 
 |   if (!BFI) | 
 |     BFI.reset(new ImplType); | 
 |   BFI->calculate(F, BPI, LI); | 
 |   if (ViewBlockFreqPropagationDAG != GVDT_None && | 
 |       (ViewBlockFreqFuncName.empty() || | 
 |        F.getName().equals(ViewBlockFreqFuncName))) { | 
 |     view(); | 
 |   } | 
 |   if (PrintBlockFreq && | 
 |       (PrintBlockFreqFuncName.empty() || | 
 |        F.getName().equals(PrintBlockFreqFuncName))) { | 
 |     print(dbgs()); | 
 |   } | 
 | } | 
 |  | 
 | BlockFrequency BlockFrequencyInfo::getBlockFreq(const BasicBlock *BB) const { | 
 |   return BFI ? BFI->getBlockFreq(BB) : 0; | 
 | } | 
 |  | 
 | Optional<uint64_t> | 
 | BlockFrequencyInfo::getBlockProfileCount(const BasicBlock *BB) const { | 
 |   if (!BFI) | 
 |     return None; | 
 |  | 
 |   return BFI->getBlockProfileCount(*getFunction(), BB); | 
 | } | 
 |  | 
 | Optional<uint64_t> | 
 | BlockFrequencyInfo::getProfileCountFromFreq(uint64_t Freq) const { | 
 |   if (!BFI) | 
 |     return None; | 
 |   return BFI->getProfileCountFromFreq(*getFunction(), Freq); | 
 | } | 
 |  | 
 | bool BlockFrequencyInfo::isIrrLoopHeader(const BasicBlock *BB) { | 
 |   assert(BFI && "Expected analysis to be available"); | 
 |   return BFI->isIrrLoopHeader(BB); | 
 | } | 
 |  | 
 | void BlockFrequencyInfo::setBlockFreq(const BasicBlock *BB, uint64_t Freq) { | 
 |   assert(BFI && "Expected analysis to be available"); | 
 |   BFI->setBlockFreq(BB, Freq); | 
 | } | 
 |  | 
 | void BlockFrequencyInfo::setBlockFreqAndScale( | 
 |     const BasicBlock *ReferenceBB, uint64_t Freq, | 
 |     SmallPtrSetImpl<BasicBlock *> &BlocksToScale) { | 
 |   assert(BFI && "Expected analysis to be available"); | 
 |   // Use 128 bits APInt to avoid overflow. | 
 |   APInt NewFreq(128, Freq); | 
 |   APInt OldFreq(128, BFI->getBlockFreq(ReferenceBB).getFrequency()); | 
 |   APInt BBFreq(128, 0); | 
 |   for (auto *BB : BlocksToScale) { | 
 |     BBFreq = BFI->getBlockFreq(BB).getFrequency(); | 
 |     // Multiply first by NewFreq and then divide by OldFreq | 
 |     // to minimize loss of precision. | 
 |     BBFreq *= NewFreq; | 
 |     // udiv is an expensive operation in the general case. If this ends up being | 
 |     // a hot spot, one of the options proposed in | 
 |     // https://reviews.llvm.org/D28535#650071 could be used to avoid this. | 
 |     BBFreq = BBFreq.udiv(OldFreq); | 
 |     BFI->setBlockFreq(BB, BBFreq.getLimitedValue()); | 
 |   } | 
 |   BFI->setBlockFreq(ReferenceBB, Freq); | 
 | } | 
 |  | 
 | /// Pop up a ghostview window with the current block frequency propagation | 
 | /// rendered using dot. | 
 | void BlockFrequencyInfo::view() const { | 
 |   ViewGraph(const_cast<BlockFrequencyInfo *>(this), "BlockFrequencyDAGs"); | 
 | } | 
 |  | 
 | const Function *BlockFrequencyInfo::getFunction() const { | 
 |   return BFI ? BFI->getFunction() : nullptr; | 
 | } | 
 |  | 
 | const BranchProbabilityInfo *BlockFrequencyInfo::getBPI() const { | 
 |   return BFI ? &BFI->getBPI() : nullptr; | 
 | } | 
 |  | 
 | raw_ostream &BlockFrequencyInfo:: | 
 | printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const { | 
 |   return BFI ? BFI->printBlockFreq(OS, Freq) : OS; | 
 | } | 
 |  | 
 | raw_ostream & | 
 | BlockFrequencyInfo::printBlockFreq(raw_ostream &OS, | 
 |                                    const BasicBlock *BB) const { | 
 |   return BFI ? BFI->printBlockFreq(OS, BB) : OS; | 
 | } | 
 |  | 
 | uint64_t BlockFrequencyInfo::getEntryFreq() const { | 
 |   return BFI ? BFI->getEntryFreq() : 0; | 
 | } | 
 |  | 
 | void BlockFrequencyInfo::releaseMemory() { BFI.reset(); } | 
 |  | 
 | void BlockFrequencyInfo::print(raw_ostream &OS) const { | 
 |   if (BFI) | 
 |     BFI->print(OS); | 
 | } | 
 |  | 
 | INITIALIZE_PASS_BEGIN(BlockFrequencyInfoWrapperPass, "block-freq", | 
 |                       "Block Frequency Analysis", true, true) | 
 | INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass) | 
 | INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass) | 
 | INITIALIZE_PASS_END(BlockFrequencyInfoWrapperPass, "block-freq", | 
 |                     "Block Frequency Analysis", true, true) | 
 |  | 
 | char BlockFrequencyInfoWrapperPass::ID = 0; | 
 |  | 
 | BlockFrequencyInfoWrapperPass::BlockFrequencyInfoWrapperPass() | 
 |     : FunctionPass(ID) { | 
 |   initializeBlockFrequencyInfoWrapperPassPass(*PassRegistry::getPassRegistry()); | 
 | } | 
 |  | 
 | BlockFrequencyInfoWrapperPass::~BlockFrequencyInfoWrapperPass() = default; | 
 |  | 
 | void BlockFrequencyInfoWrapperPass::print(raw_ostream &OS, | 
 |                                           const Module *) const { | 
 |   BFI.print(OS); | 
 | } | 
 |  | 
 | void BlockFrequencyInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { | 
 |   AU.addRequired<BranchProbabilityInfoWrapperPass>(); | 
 |   AU.addRequired<LoopInfoWrapperPass>(); | 
 |   AU.setPreservesAll(); | 
 | } | 
 |  | 
 | void BlockFrequencyInfoWrapperPass::releaseMemory() { BFI.releaseMemory(); } | 
 |  | 
 | bool BlockFrequencyInfoWrapperPass::runOnFunction(Function &F) { | 
 |   BranchProbabilityInfo &BPI = | 
 |       getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI(); | 
 |   LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo(); | 
 |   BFI.calculate(F, BPI, LI); | 
 |   return false; | 
 | } | 
 |  | 
 | AnalysisKey BlockFrequencyAnalysis::Key; | 
 | BlockFrequencyInfo BlockFrequencyAnalysis::run(Function &F, | 
 |                                                FunctionAnalysisManager &AM) { | 
 |   BlockFrequencyInfo BFI; | 
 |   BFI.calculate(F, AM.getResult<BranchProbabilityAnalysis>(F), | 
 |                 AM.getResult<LoopAnalysis>(F)); | 
 |   return BFI; | 
 | } | 
 |  | 
 | PreservedAnalyses | 
 | BlockFrequencyPrinterPass::run(Function &F, FunctionAnalysisManager &AM) { | 
 |   OS << "Printing analysis results of BFI for function " | 
 |      << "'" << F.getName() << "':" | 
 |      << "\n"; | 
 |   AM.getResult<BlockFrequencyAnalysis>(F).print(OS); | 
 |   return PreservedAnalyses::all(); | 
 | } |