llvm-project/llvm/lib/CodeGen/MachineBlockFrequencyInfo.cpp

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//====------ MachineBlockFrequencyInfo.cpp - MBB 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/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/Analysis/BlockFrequencyImpl.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GraphWriter.h"
using namespace llvm;
#ifndef NDEBUG
enum GVDAGType {
GVDT_None,
GVDT_Fraction,
GVDT_Integer
};
static cl::opt<GVDAGType>
ViewMachineBlockFreqPropagationDAG("view-machine-block-freq-propagation-dags",
cl::Hidden,
cl::desc("Pop up a window to show a dag displaying how machine block "
"frequencies propagate 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<MachineBlockFrequencyInfo *> {
typedef const MachineBasicBlock NodeType;
typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
typedef MachineFunction::const_iterator nodes_iterator;
static inline
const NodeType *getEntryNode(const MachineBlockFrequencyInfo *G) {
return G->getFunction()->begin();
}
static ChildIteratorType child_begin(const NodeType *N) {
return N->succ_begin();
}
static ChildIteratorType child_end(const NodeType *N) {
return N->succ_end();
}
static nodes_iterator nodes_begin(const MachineBlockFrequencyInfo *G) {
return G->getFunction()->begin();
}
static nodes_iterator nodes_end(const MachineBlockFrequencyInfo *G) {
return G->getFunction()->end();
}
};
template<>
struct DOTGraphTraits<MachineBlockFrequencyInfo*> :
public DefaultDOTGraphTraits {
explicit DOTGraphTraits(bool isSimple=false) :
DefaultDOTGraphTraits(isSimple) {}
static std::string getGraphName(const MachineBlockFrequencyInfo *G) {
return G->getFunction()->getName();
}
std::string getNodeLabel(const MachineBasicBlock *Node,
const MachineBlockFrequencyInfo *Graph) {
std::string Result;
raw_string_ostream OS(Result);
OS << Node->getName().str() << ":";
switch (ViewMachineBlockFreqPropagationDAG) {
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(MachineBlockFrequencyInfo, "machine-block-freq",
"Machine Block Frequency Analysis", true, true)
INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
INITIALIZE_PASS_END(MachineBlockFrequencyInfo, "machine-block-freq",
"Machine Block Frequency Analysis", true, true)
char MachineBlockFrequencyInfo::ID = 0;
MachineBlockFrequencyInfo::
MachineBlockFrequencyInfo() :MachineFunctionPass(ID) {
initializeMachineBlockFrequencyInfoPass(*PassRegistry::getPassRegistry());
MBFI = new BlockFrequencyImpl<MachineBasicBlock, MachineFunction,
MachineBranchProbabilityInfo>();
}
MachineBlockFrequencyInfo::~MachineBlockFrequencyInfo() {
delete MBFI;
}
void MachineBlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<MachineBranchProbabilityInfo>();
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool MachineBlockFrequencyInfo::runOnMachineFunction(MachineFunction &F) {
MachineBranchProbabilityInfo &MBPI =
getAnalysis<MachineBranchProbabilityInfo>();
MBFI->doFunction(&F, &MBPI);
#ifndef NDEBUG
if (ViewMachineBlockFreqPropagationDAG != GVDT_None) {
view();
}
#endif
return false;
}
/// Pop up a ghostview window with the current block frequency propagation
/// rendered using dot.
void MachineBlockFrequencyInfo::view() const {
// This code is only for debugging.
#ifndef NDEBUG
ViewGraph(const_cast<MachineBlockFrequencyInfo *>(this),
"MachineBlockFrequencyDAGs");
#else
errs() << "MachineBlockFrequencyInfo::view is only available in debug builds "
"on systems with Graphviz or gv!\n";
#endif // NDEBUG
}
BlockFrequency MachineBlockFrequencyInfo::
getBlockFreq(const MachineBasicBlock *MBB) const {
return MBFI->getBlockFreq(MBB);
}
MachineFunction *MachineBlockFrequencyInfo::getFunction() const {
return MBFI->Fn;
}
raw_ostream &
MachineBlockFrequencyInfo::printBlockFreq(raw_ostream &OS,
const BlockFrequency Freq) const {
return MBFI->printBlockFreq(OS, Freq);
}
raw_ostream &
MachineBlockFrequencyInfo::printBlockFreq(raw_ostream &OS,
const MachineBasicBlock *MBB) const {
return MBFI->printBlockFreq(OS, MBB);
}
uint64_t MachineBlockFrequencyInfo::getEntryFreq() const {
return MBFI->getEntryFreq();
}