1 //=======-------- BlockFrequencyInfo.cpp - Block Frequency 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 // 10 // Loops should be simplified before this analysis. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/InitializePasses.h" 15 #include "llvm/Analysis/BlockFrequencyImpl.h" 16 #include "llvm/Analysis/BlockFrequencyInfo.h" 17 #include "llvm/Analysis/LoopInfo.h" 18 #include "llvm/Analysis/Passes.h" 19 #include "llvm/Analysis/BranchProbabilityInfo.h" 20 21 using namespace llvm; 22 23 INITIALIZE_PASS_BEGIN(BlockFrequencyInfo, "block-freq", "Block Frequency Analysis", 24 true, true) 25 INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfo) 26 INITIALIZE_PASS_END(BlockFrequencyInfo, "block-freq", "Block Frequency Analysis", 27 true, true) 28 29 char BlockFrequencyInfo::ID = 0; 30 31 32 BlockFrequencyInfo::BlockFrequencyInfo() : FunctionPass(ID) { 33 initializeBlockFrequencyInfoPass(*PassRegistry::getPassRegistry()); 34 BFI = new BlockFrequencyImpl<BasicBlock, Function, BranchProbabilityInfo>(); 35 } 36 37 BlockFrequencyInfo::~BlockFrequencyInfo() { 38 delete BFI; 39 } 40 41 void BlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const { 42 AU.addRequired<BranchProbabilityInfo>(); 43 AU.setPreservesAll(); 44 } 45 46 bool BlockFrequencyInfo::runOnFunction(Function &F) { 47 BranchProbabilityInfo &BPI = getAnalysis<BranchProbabilityInfo>(); 48 BFI->doFunction(&F, &BPI); 49 return false; 50 } 51 52 void BlockFrequencyInfo::print(raw_ostream &O, const Module *) const { 53 if (BFI) BFI->print(O); 54 } 55 56 /// getblockFreq - Return block frequency. Return 0 if we don't have the 57 /// information. Please note that initial frequency is equal to 1024. It means 58 /// that we should not rely on the value itself, but only on the comparison to 59 /// the other block frequencies. We do this to avoid using of floating points. 60 /// 61 BlockFrequency BlockFrequencyInfo::getBlockFreq(BasicBlock *BB) const { 62 return BFI->getBlockFreq(BB); 63 } 64
