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//===- BlockFrequencyInfo.cpp - Block Frequency Analysis ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Loops should be simplified before this analysis.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/IR/CFG.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GraphWriter.h"
using namespace llvm;
#define DEBUG_TYPE "block-freq"
#ifndef NDEBUG
enum GVDAGType {
GVDT_None,
GVDT_Fraction,
GVDT_Integer
};
static cl::opt<GVDAGType>
ViewBlockFreqPropagationDAG("view-block-freq-propagation-dags", cl::Hidden,
cl::desc("Pop up a window to show a dag displaying how block "
"frequencies propagation through the CFG."),
cl::values(
clEnumValN(GVDT_None, "none",
"do not display graphs."),
clEnumValN(GVDT_Fraction, "fraction", "display a graph using the "
"fractional block frequency representation."),
clEnumValN(GVDT_Integer, "integer", "display a graph using the raw "
"integer fractional block frequency representation."),
clEnumValEnd));
namespace llvm {
template <>
struct GraphTraits<BlockFrequencyInfo *> {
typedef const BasicBlock NodeType;
typedef succ_const_iterator ChildIteratorType;
typedef Function::const_iterator nodes_iterator;
static inline const NodeType *getEntryNode(const BlockFrequencyInfo *G) {
return G->getFunction()->begin();
}
static ChildIteratorType child_begin(const NodeType *N) {
return succ_begin(N);
}
static ChildIteratorType child_end(const NodeType *N) {
return succ_end(N);
}
static nodes_iterator nodes_begin(const BlockFrequencyInfo *G) {
return G->getFunction()->begin();
}
static nodes_iterator nodes_end(const BlockFrequencyInfo *G) {
return G->getFunction()->end();
}
};
template<>
struct DOTGraphTraits<BlockFrequencyInfo*> : public DefaultDOTGraphTraits {
explicit DOTGraphTraits(bool isSimple=false) :
DefaultDOTGraphTraits(isSimple) {}
static std::string getGraphName(const BlockFrequencyInfo *G) {
return G->getFunction()->getName();
}
std::string getNodeLabel(const BasicBlock *Node,
const BlockFrequencyInfo *Graph) {
std::string Result;
raw_string_ostream OS(Result);
OS << Node->getName().str() << ":";
switch (ViewBlockFreqPropagationDAG) {
case GVDT_Fraction:
Graph->printBlockFreq(OS, Node);
break;
case GVDT_Integer:
OS << Graph->getBlockFreq(Node).getFrequency();
break;
case GVDT_None:
llvm_unreachable("If we are not supposed to render a graph we should "
"never reach this point.");
}
return Result;
}
};
} // end namespace llvm
#endif
INITIALIZE_PASS_BEGIN(BlockFrequencyInfo, "block-freq",
"Block Frequency Analysis", true, true)
INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfo)
INITIALIZE_PASS_DEPENDENCY(LoopInfo)
INITIALIZE_PASS_END(BlockFrequencyInfo, "block-freq",
"Block Frequency Analysis", true, true)
char BlockFrequencyInfo::ID = 0;
BlockFrequencyInfo::BlockFrequencyInfo() : FunctionPass(ID) {
initializeBlockFrequencyInfoPass(*PassRegistry::getPassRegistry());
}
BlockFrequencyInfo::~BlockFrequencyInfo() {}
void BlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<BranchProbabilityInfo>();
AU.addRequired<LoopInfo>();
AU.setPreservesAll();
}
bool BlockFrequencyInfo::runOnFunction(Function &F) {
BranchProbabilityInfo &BPI = getAnalysis<BranchProbabilityInfo>();
LoopInfo &LI = getAnalysis<LoopInfo>();
if (!BFI)
BFI.reset(new ImplType);
BFI->doFunction(&F, &BPI, &LI);
#ifndef NDEBUG
if (ViewBlockFreqPropagationDAG != GVDT_None)
view();
#endif
return false;
}
void BlockFrequencyInfo::releaseMemory() { BFI.reset(); }
void BlockFrequencyInfo::print(raw_ostream &O, const Module *) const {
if (BFI) BFI->print(O);
}
BlockFrequency BlockFrequencyInfo::getBlockFreq(const BasicBlock *BB) const {
return BFI ? BFI->getBlockFreq(BB) : 0;
}
/// Pop up a ghostview window with the current block frequency propagation
/// rendered using dot.
void BlockFrequencyInfo::view() const {
// This code is only for debugging.
#ifndef NDEBUG
ViewGraph(const_cast<BlockFrequencyInfo *>(this), "BlockFrequencyDAGs");
#else
errs() << "BlockFrequencyInfo::view is only available in debug builds on "
"systems with Graphviz or gv!\n";
#endif // NDEBUG
}
const Function *BlockFrequencyInfo::getFunction() const {
return BFI ? BFI->getFunction() : nullptr;
}
raw_ostream &BlockFrequencyInfo::
printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const {
return BFI ? BFI->printBlockFreq(OS, Freq) : OS;
}
raw_ostream &
BlockFrequencyInfo::printBlockFreq(raw_ostream &OS,
const BasicBlock *BB) const {
return BFI ? BFI->printBlockFreq(OS, BB) : OS;
}
uint64_t BlockFrequencyInfo::getEntryFreq() const {
return BFI ? BFI->getEntryFreq() : 0;
}
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