MachineBlockFrequencyInfo.cpp revision f55c1c85881afd65647bde5346f64d9685235c7c 
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/InitializePasses.h"
15#include "llvm/Analysis/BlockFrequencyImpl.h"
16#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
17#include "llvm/CodeGen/Passes.h"
18#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
19
20using namespace llvm;
21
22INITIALIZE_PASS_BEGIN(MachineBlockFrequencyInfo, "machine-block-freq",
23                      "Machine Block Frequency Analysis", true, true)
24INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
25INITIALIZE_PASS_END(MachineBlockFrequencyInfo, "machine-block-freq",
26                    "Machine Block Frequency Analysis", true, true)
27
28char MachineBlockFrequencyInfo::ID = 0;
29
30
31MachineBlockFrequencyInfo::MachineBlockFrequencyInfo() : MachineFunctionPass(ID) {
32  initializeMachineBlockFrequencyInfoPass(*PassRegistry::getPassRegistry());
33  MBFI = new BlockFrequencyImpl<MachineBasicBlock, MachineFunction,
34                                MachineBranchProbabilityInfo>();
35}
36
37MachineBlockFrequencyInfo::~MachineBlockFrequencyInfo() {
38  delete MBFI;
39}
40
41void MachineBlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const {
42  AU.addRequired<MachineBranchProbabilityInfo>();
43  AU.setPreservesAll();
44  MachineFunctionPass::getAnalysisUsage(AU);
45}
46
47bool 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///
58uint32_t MachineBlockFrequencyInfo::getBlockFreq(MachineBasicBlock *MBB) {
59  return MBFI->getBlockFreq(MBB);
60}
61