contrib/llvm/lib/Analysis/LazyBranchProbabilityInfo.cpp

   1 //===- LazyBranchProbabilityInfo.cpp - Lazy Branch Probability 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 BranchProbabilityInfoWrapperPass.
  11 // The difference is that with this pass the branch probabilities are not
  12 // computed when the analysis pass is executed but rather when the BPI results
  13 // is explicitly requested by the analysis client.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #include "llvm/Analysis/LazyBranchProbabilityInfo.h"
  18 #include "llvm/Analysis/LoopInfo.h"
  19 #include "llvm/Analysis/TargetLibraryInfo.h"
  20
  21 using namespace llvm;
  22
  23 #define DEBUG_TYPE "lazy-branch-prob"
  24
  25 INITIALIZE_PASS_BEGIN(LazyBranchProbabilityInfoPass, DEBUG_TYPE,
  26                       "Lazy Branch Probability Analysis", true, true)
  27 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
  28 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
  29 INITIALIZE_PASS_END(LazyBranchProbabilityInfoPass, DEBUG_TYPE,
  30                     "Lazy Branch Probability Analysis", true, true)
  31
  32 char LazyBranchProbabilityInfoPass::ID = 0;
  33
  34 LazyBranchProbabilityInfoPass::LazyBranchProbabilityInfoPass()
  35     : FunctionPass(ID) {
  36   initializeLazyBranchProbabilityInfoPassPass(*PassRegistry::getPassRegistry());
  37 }
  38
  39 void LazyBranchProbabilityInfoPass::print(raw_ostream &OS,
  40                                           const Module *) const {
  41   LBPI->getCalculated().print(OS);
  42 }
  43
  44 void LazyBranchProbabilityInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
  45   AU.addRequired<LoopInfoWrapperPass>();
  46   AU.addRequired<TargetLibraryInfoWrapperPass>();
  47   AU.setPreservesAll();
  48 }
  49
  50 void LazyBranchProbabilityInfoPass::releaseMemory() { LBPI.reset(); }
  51
  52 bool LazyBranchProbabilityInfoPass::runOnFunction(Function &F) {
  53   LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
  54   TargetLibraryInfo &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
  55   LBPI = llvm::make_unique<LazyBranchProbabilityInfo>(&F, &LI, &TLI);
  56   return false;
  57 }
  58
  59 void LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AnalysisUsage &AU) {
  60   AU.addRequired<LazyBranchProbabilityInfoPass>();
  61   AU.addRequired<LoopInfoWrapperPass>();
  62   AU.addRequired<TargetLibraryInfoWrapperPass>();
  63 }
  64
  65 void llvm::initializeLazyBPIPassPass(PassRegistry &Registry) {
  66   INITIALIZE_PASS_DEPENDENCY(LazyBranchProbabilityInfoPass);
  67   INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
  68   INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass);
  69 }