contrib/llvm/lib/Analysis/LazyBlockFrequencyInfo.cpp

   1 //===- LazyBlockFrequencyInfo.cpp - Lazy 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 // This is an alternative analysis pass to BlockFrequencyInfoWrapperPass.  The
  11 // difference is that with this pass the block frequencies are not computed when
  12 // the analysis pass is executed but rather when the BFI results is explicitly
  13 // requested by the analysis client.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #include "llvm/Analysis/LazyBlockFrequencyInfo.h"
  18 #include "llvm/Analysis/BranchProbabilityInfo.h"
  19 #include "llvm/Analysis/LoopInfo.h"
  20
  21 using namespace llvm;
  22
  23 #define DEBUG_TYPE "lazy-block-freq"
  24
  25 INITIALIZE_PASS_BEGIN(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
  26                       "Lazy Block Frequency Analysis", true, true)
  27 INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
  28 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
  29 INITIALIZE_PASS_END(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
  30                     "Lazy Block Frequency Analysis", true, true)
  31
  32 char LazyBlockFrequencyInfoPass::ID = 0;
  33
  34 LazyBlockFrequencyInfoPass::LazyBlockFrequencyInfoPass() : FunctionPass(ID) {
  35   initializeLazyBlockFrequencyInfoPassPass(*PassRegistry::getPassRegistry());
  36 }
  37
  38 void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const {
  39   LBFI.getCalculated().print(OS);
  40 }
  41
  42 void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
  43   AU.addRequired<BranchProbabilityInfoWrapperPass>();
  44   AU.addRequired<LoopInfoWrapperPass>();
  45   AU.setPreservesAll();
  46 }
  47
  48 void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); }
  49
  50 bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) {
  51   BranchProbabilityInfo &BPI =
  52       getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
  53   LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
  54   LBFI.setAnalysis(&F, &BPI, &LI);
  55   return false;
  56 }
  57
  58 void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) {
  59   AU.addRequired<BranchProbabilityInfoWrapperPass>();
  60   AU.addRequired<LazyBlockFrequencyInfoPass>();
  61   AU.addRequired<LoopInfoWrapperPass>();
  62 }
  63
  64 void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) {
  65   INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass);
  66   INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass);
  67   INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
  68 }