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) {
87 OS << Node->getName() << ":";
88 switch (ViewBlockFreqPropagationDAG) {
90 Graph->printBlockFreq(OS, Node);
93 OS << Graph->getBlockFreq(Node).getFrequency();
96 llvm_unreachable("If we are not supposed to render a graph we should "
97 "never reach this point.");
104 } // end namespace llvm
107 INITIALIZE_PASS_BEGIN(BlockFrequencyInfo, "block-freq",
108 "Block Frequency Analysis", true, true)
109 INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfo)
110 INITIALIZE_PASS_DEPENDENCY(LoopInfo)
111 INITIALIZE_PASS_END(BlockFrequencyInfo, "block-freq",
112 "Block Frequency Analysis", true, true)
114 char BlockFrequencyInfo::ID = 0;
117 BlockFrequencyInfo::BlockFrequencyInfo() : FunctionPass(ID) {
118 initializeBlockFrequencyInfoPass(*PassRegistry::getPassRegistry());
121 BlockFrequencyInfo::~BlockFrequencyInfo() {}
123 void BlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const {
124 AU.addRequired<BranchProbabilityInfo>();
125 AU.addRequired<LoopInfo>();
126 AU.setPreservesAll();
129 bool BlockFrequencyInfo::runOnFunction(Function &F) {
130 BranchProbabilityInfo &BPI = getAnalysis<BranchProbabilityInfo>();
131 LoopInfo &LI = getAnalysis<LoopInfo>();
133 BFI.reset(new ImplType);
134 BFI->doFunction(&F, &BPI, &LI);
136 if (ViewBlockFreqPropagationDAG != GVDT_None)
142 void BlockFrequencyInfo::releaseMemory() { BFI.reset(); }
144 void BlockFrequencyInfo::print(raw_ostream &O, const Module *) const {
145 if (BFI) BFI->print(O);
148 BlockFrequency BlockFrequencyInfo::getBlockFreq(const BasicBlock *BB) const {
149 return BFI ? BFI->getBlockFreq(BB) : 0;
152 /// Pop up a ghostview window with the current block frequency propagation
153 /// rendered using dot.
154 void BlockFrequencyInfo::view() const {
155 // This code is only for debugging.
157 ViewGraph(const_cast<BlockFrequencyInfo *>(this), "BlockFrequencyDAGs");
159 errs() << "BlockFrequencyInfo::view is only available in debug builds on "
160 "systems with Graphviz or gv!\n";
164 const Function *BlockFrequencyInfo::getFunction() const {
165 return BFI ? BFI->getFunction() : nullptr;
168 raw_ostream &BlockFrequencyInfo::
169 printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const {
170 return BFI ? BFI->printBlockFreq(OS, Freq) : OS;
174 BlockFrequencyInfo::printBlockFreq(raw_ostream &OS,
175 const BasicBlock *BB) const {
176 return BFI ? BFI->printBlockFreq(OS, BB) : OS;
179 uint64_t BlockFrequencyInfo::getEntryFreq() const {
180 return BFI ? BFI->getEntryFreq() : 0;