1 //=======-------- BlockFrequency.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/BlockFrequency.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(BlockFrequency, "block-freq", "Block Frequency Analysis",
24 true, true)
25 INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfo)
26 INITIALIZE_PASS_END(BlockFrequency, "block-freq", "Block Frequency Analysis",
27 true, true)
28
29 char BlockFrequency::ID = 0;
30
31
BlockFrequency()32 BlockFrequency::BlockFrequency() : FunctionPass(ID) {
33 initializeBlockFrequencyPass(*PassRegistry::getPassRegistry());
34 BFI = new BlockFrequencyImpl<BasicBlock, Function, BranchProbabilityInfo>();
35 }
36
~BlockFrequency()37 BlockFrequency::~BlockFrequency() {
38 delete BFI;
39 }
40
getAnalysisUsage(AnalysisUsage & AU) const41 void BlockFrequency::getAnalysisUsage(AnalysisUsage &AU) const {
42 AU.addRequired<BranchProbabilityInfo>();
43 AU.setPreservesAll();
44 }
45
runOnFunction(Function & F)46 bool BlockFrequency::runOnFunction(Function &F) {
47 BranchProbabilityInfo &BPI = getAnalysis<BranchProbabilityInfo>();
48 BFI->doFunction(&F, &BPI);
49 return false;
50 }
51
52 /// getblockFreq - Return block frequency. Never return 0, value must be
53 /// positive. Please note that initial frequency is equal to 1024. It means that
54 /// we should not rely on the value itself, but only on the comparison to the
55 /// other block frequencies. We do this to avoid using of floating points.
56 ///
getBlockFreq(BasicBlock * BB)57 uint32_t BlockFrequency::getBlockFreq(BasicBlock *BB) {
58 return BFI->getBlockFreq(BB);
59 }
60