1 //===- BlockFrequencyInfo.cpp - Block Frequency Analysis ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Loops should be simplified before this analysis.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Analysis/BlockFrequencyInfo.h"
15 #include "llvm/Analysis/BlockFrequencyInfoImpl.h"
16 #include "llvm/Analysis/BranchProbabilityInfo.h"
17 #include "llvm/Analysis/LoopInfo.h"
18 #include "llvm/Analysis/Passes.h"
19 #include "llvm/IR/CFG.h"
20 #include "llvm/InitializePasses.h"
21 #include "llvm/Support/CommandLine.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/GraphWriter.h"
27 #define DEBUG_TYPE "block-freq"
36 static cl::opt<GVDAGType>
37 ViewBlockFreqPropagationDAG("view-block-freq-propagation-dags", cl::Hidden,
38 cl::desc("Pop up a window to show a dag displaying how block "
39 "frequencies propagation through the CFG."),
41 clEnumValN(GVDT_None, "none",
42 "do not display graphs."),
43 clEnumValN(GVDT_Fraction, "fraction", "display a graph using the "
44 "fractional block frequency representation."),
45 clEnumValN(GVDT_Integer, "integer", "display a graph using the raw "
46 "integer fractional block frequency representation."),
52 struct GraphTraits<BlockFrequencyInfo *> {
53 typedef const BasicBlock NodeType;
54 typedef succ_const_iterator ChildIteratorType;
55 typedef Function::const_iterator nodes_iterator;
57 static inline const NodeType *getEntryNode(const BlockFrequencyInfo *G) {
58 return G->getFunction()->begin();
60 static ChildIteratorType child_begin(const NodeType *N) {
63 static ChildIteratorType child_end(const NodeType *N) {
66 static nodes_iterator nodes_begin(const BlockFrequencyInfo *G) {
67 return G->getFunction()->begin();
69 static nodes_iterator nodes_end(const BlockFrequencyInfo *G) {
70 return G->getFunction()->end();
75 struct DOTGraphTraits<BlockFrequencyInfo*> : public DefaultDOTGraphTraits {
76 explicit DOTGraphTraits(bool isSimple=false) :
77 DefaultDOTGraphTraits(isSimple) {}
79 static std::string getGraphName(const BlockFrequencyInfo *G) {
80 return G->getFunction()->getName();
83 std::string getNodeLabel(const BasicBlock *Node,
84 const BlockFrequencyInfo *Graph) {
86 raw_string_ostream OS(Result);
88 OS << Node->getName() << ":";
89 switch (ViewBlockFreqPropagationDAG) {
91 Graph->printBlockFreq(OS, Node);
94 OS << Graph->getBlockFreq(Node).getFrequency();
97 llvm_unreachable("If we are not supposed to render a graph we should "
98 "never reach this point.");
105 } // end namespace llvm
108 void BlockFrequencyInfo::calculate(const Function &F,
109 const BranchProbabilityInfo &BPI,
110 const LoopInfo &LI) {
112 BFI.reset(new ImplType);
113 BFI->calculate(F, BPI, LI);
115 if (ViewBlockFreqPropagationDAG != GVDT_None)
120 BlockFrequency BlockFrequencyInfo::getBlockFreq(const BasicBlock *BB) const {
121 return BFI ? BFI->getBlockFreq(BB) : 0;
124 /// Pop up a ghostview window with the current block frequency propagation
125 /// rendered using dot.
126 void BlockFrequencyInfo::view() const {
127 // This code is only for debugging.
129 ViewGraph(const_cast<BlockFrequencyInfo *>(this), "BlockFrequencyDAGs");
131 errs() << "BlockFrequencyInfo::view is only available in debug builds on "
132 "systems with Graphviz or gv!\n";
136 const Function *BlockFrequencyInfo::getFunction() const {
137 return BFI ? BFI->getFunction() : nullptr;
140 raw_ostream &BlockFrequencyInfo::
141 printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const {
142 return BFI ? BFI->printBlockFreq(OS, Freq) : OS;
146 BlockFrequencyInfo::printBlockFreq(raw_ostream &OS,
147 const BasicBlock *BB) const {
148 return BFI ? BFI->printBlockFreq(OS, BB) : OS;
151 uint64_t BlockFrequencyInfo::getEntryFreq() const {
152 return BFI ? BFI->getEntryFreq() : 0;
155 void BlockFrequencyInfo::releaseMemory() { BFI.reset(); }
157 void BlockFrequencyInfo::print(raw_ostream &OS) const {
163 INITIALIZE_PASS_BEGIN(BlockFrequencyInfoWrapperPass, "block-freq",
164 "Block Frequency Analysis", true, true)
165 INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfo)
166 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
167 INITIALIZE_PASS_END(BlockFrequencyInfoWrapperPass, "block-freq",
168 "Block Frequency Analysis", true, true)
170 char BlockFrequencyInfoWrapperPass::ID = 0;
173 BlockFrequencyInfoWrapperPass::BlockFrequencyInfoWrapperPass()
175 initializeBlockFrequencyInfoWrapperPassPass(*PassRegistry::getPassRegistry());
178 BlockFrequencyInfoWrapperPass::~BlockFrequencyInfoWrapperPass() {}
180 void BlockFrequencyInfoWrapperPass::print(raw_ostream &OS,
181 const Module *) const {
185 void BlockFrequencyInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
186 AU.addRequired<BranchProbabilityInfo>();
187 AU.addRequired<LoopInfoWrapperPass>();
188 AU.setPreservesAll();
191 void BlockFrequencyInfoWrapperPass::releaseMemory() { BFI.releaseMemory(); }
193 bool BlockFrequencyInfoWrapperPass::runOnFunction(Function &F) {
194 BranchProbabilityInfo &BPI = getAnalysis<BranchProbabilityInfo>();
195 LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
196 BFI.calculate(F, BPI, LI);