1 //====----- MachineBlockFrequencyInfo.cpp - Machine 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/CodeGen/MachineBlockFrequencyInfo.h" 15 #include "llvm/Analysis/BlockFrequencyImpl.h" 16 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h" 17 #include "llvm/CodeGen/Passes.h" 18 #include "llvm/InitializePasses.h" 19 20 using namespace llvm; 21 22 INITIALIZE_PASS_BEGIN(MachineBlockFrequencyInfo, "machine-block-freq", 23 "Machine Block Frequency Analysis", true, true) 24 INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo) 25 INITIALIZE_PASS_END(MachineBlockFrequencyInfo, "machine-block-freq", 26 "Machine Block Frequency Analysis", true, true) 27 28 char MachineBlockFrequencyInfo::ID = 0; 29 30 31 MachineBlockFrequencyInfo::MachineBlockFrequencyInfo() : MachineFunctionPass(ID) { 32 initializeMachineBlockFrequencyInfoPass(*PassRegistry::getPassRegistry()); 33 MBFI = new BlockFrequencyImpl<MachineBasicBlock, MachineFunction, 34 MachineBranchProbabilityInfo>(); 35 } 36 37 MachineBlockFrequencyInfo::~MachineBlockFrequencyInfo() { 38 delete MBFI; 39 } 40 41 void MachineBlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const { 42 AU.addRequired<MachineBranchProbabilityInfo>(); 43 AU.setPreservesAll(); 44 MachineFunctionPass::getAnalysisUsage(AU); 45 } 46 47 bool MachineBlockFrequencyInfo::runOnMachineFunction(MachineFunction &F) { 48 MachineBranchProbabilityInfo &MBPI = getAnalysis<MachineBranchProbabilityInfo>(); 49 MBFI->doFunction(&F, &MBPI); 50 return false; 51 } 52 53 /// getblockFreq - Return block frequency. Return 0 if we don't have the 54 /// information. Please note that initial frequency is equal to 1024. It means 55 /// that we should not rely on the value itself, but only on the comparison to 56 /// the other block frequencies. We do this to avoid using of floating points. 57 /// 58 BlockFrequency MachineBlockFrequencyInfo:: 59 getBlockFreq(const MachineBasicBlock *MBB) const { 60 return MBFI->getBlockFreq(MBB); 61 } 62
