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//===-- CFGPrinter.h - CFG printer external interface -----------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This file defines a 'dot-cfg' analysis pass, which emits the

// cfg.<fnname>.dot file for each function in the program, with a graph of the

// CFG for that function.

//

// This file defines external functions that can be called to explicitly

// instantiate the CFG printer.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_CFGPRINTER_H

#define LLVM_ANALYSIS_CFGPRINTER_H

#include "llvm/Analysis/BlockFrequencyInfo.h"

#include "llvm/Analysis/BranchProbabilityInfo.h"

#include "llvm/Analysis/HeatUtils.h"

#include "llvm/IR/CFG.h"

#include "llvm/IR/Constants.h"

#include "llvm/IR/Function.h"

#include "llvm/IR/Instructions.h"

#include "llvm/IR/PassManager.h"

#include "llvm/IR/ProfDataUtils.h"

#include "llvm/Support/DOTGraphTraits.h"

#include "llvm/Support/FormatVariadic.h"

namespace llvm {

template <class GraphType> struct GraphTraits;

class CFGViewerPass : public PassInfoMixin<CFGViewerPass> {

public:

  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);

};

class CFGOnlyViewerPass : public PassInfoMixin<CFGOnlyViewerPass> {

public:

  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);

};

class CFGPrinterPass : public PassInfoMixin<CFGPrinterPass> {

public:

  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);

};

class CFGOnlyPrinterPass : public PassInfoMixin<CFGOnlyPrinterPass> {

public:

  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);

};

class DOTFuncInfo {

private:

  const Function *F;

  const BlockFrequencyInfo *BFI;

  const BranchProbabilityInfo *BPI;

  uint64_t MaxFreq;

  bool ShowHeat;

  bool EdgeWeights;

  bool RawWeights;

public:

  DOTFuncInfo(const Function *F) : DOTFuncInfo(F, nullptr, nullptr, 0) {}

  DOTFuncInfo(const Function *F, const BlockFrequencyInfo *BFI,

              const BranchProbabilityInfo *BPI, uint64_t MaxFreq)

      : F(F), BFI(BFI), BPI(BPI), MaxFreq(MaxFreq) {

    ShowHeat = false;

    EdgeWeights = !!BPI; // Print EdgeWeights when BPI is available.

    RawWeights = !!BFI;  // Print RawWeights when BFI is available.

  }

  const BlockFrequencyInfo *getBFI() const { return BFI; }

  const BranchProbabilityInfo *getBPI() const { return BPI; }

  const Function *getFunction() const { return this->F; }

  uint64_t getMaxFreq() const { return MaxFreq; }

  uint64_t getFreq(const BasicBlock *BB) const {

    return BFI->getBlockFreq(BB).getFrequency();

  }

  void setHeatColors(bool ShowHeat) { this->ShowHeat = ShowHeat; }

  bool showHeatColors() { return ShowHeat; }

  void setRawEdgeWeights(bool RawWeights) { this->RawWeights = RawWeights; }

  bool useRawEdgeWeights() { return RawWeights; }

  void setEdgeWeights(bool EdgeWeights) { this->EdgeWeights = EdgeWeights; }

  bool showEdgeWeights() { return EdgeWeights; }

};

template <>

struct GraphTraits<DOTFuncInfo *> : public GraphTraits<const BasicBlock *> {

  static NodeRef getEntryNode(DOTFuncInfo *CFGInfo) {

    return &(CFGInfo->getFunction()->getEntryBlock());

  }

  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph

  using nodes_iterator = pointer_iterator<Function::const_iterator>;

  static nodes_iterator nodes_begin(DOTFuncInfo *CFGInfo) {

    return nodes_iterator(CFGInfo->getFunction()->begin());

  }

  static nodes_iterator nodes_end(DOTFuncInfo *CFGInfo) {

    return nodes_iterator(CFGInfo->getFunction()->end());

  }

  static size_t size(DOTFuncInfo *CFGInfo) {

    return CFGInfo->getFunction()->size();

  }

};

template <typename BasicBlockT>

std::string SimpleNodeLabelString(const BasicBlockT *Node) {

  if (!Node->getName().empty())

    return Node->getName().str();

  std::string Str;

  raw_string_ostream OS(Str);

  Node->printAsOperand(OS, false);

  return OS.str();

}

template <typename BasicBlockT>

std::string CompleteNodeLabelString(

    const BasicBlockT *Node,

    function_ref<void(raw_string_ostream &, const BasicBlockT &)>

        HandleBasicBlock,

    function_ref<void(std::string &, unsigned &, unsigned)>

        HandleComment) {

  enum { MaxColumns = 80 };

  std::string Str;

  raw_string_ostream OS(Str);

  if (Node->getName().empty()) {

    Node->printAsOperand(OS, false);

    OS << ':';

  }

  HandleBasicBlock(OS, *Node);

  std::string OutStr = OS.str();

  if (OutStr[0] == '\n')

    OutStr.erase(OutStr.begin());

  unsigned ColNum = 0;

  unsigned LastSpace = 0;

  for (unsigned i = 0; i != OutStr.length(); ++i) {

    if (OutStr[i] == '\n') { // Left justify

      OutStr[i] = '\\';

      OutStr.insert(OutStr.begin() + i + 1, 'l');

      ColNum = 0;

      LastSpace = 0;

    } else if (OutStr[i] == ';') {             // Delete comments!

      unsigned Idx = OutStr.find('\n', i + 1); // Find end of line

      HandleComment(OutStr, i, Idx);

    } else if (ColNum == MaxColumns) { // Wrap lines.

      // Wrap very long names even though we can't find a space.

      if (!LastSpace)

        LastSpace = i;

      OutStr.insert(LastSpace, "\\l...");

      ColNum = i - LastSpace;

      LastSpace = 0;

      i += 3; // The loop will advance 'i' again.

    } else

      ++ColNum;

    if (OutStr[i] == ' ')

      LastSpace = i;

  }

  return OutStr;

}

template <>

struct DOTGraphTraits<DOTFuncInfo *> : public DefaultDOTGraphTraits {

  // Cache for is hidden property

  DenseMap<const BasicBlock *, bool> isOnDeoptOrUnreachablePath;

  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}

  static void eraseComment(std::string &OutStr, unsigned &I, unsigned Idx) {

    OutStr.erase(OutStr.begin() + I, OutStr.begin() + Idx);

    --I;

  }

  static std::string getGraphName(DOTFuncInfo *CFGInfo) {

    return "CFG for '" + CFGInfo->getFunction()->getName().str() + "' function";

  }

  static std::string getSimpleNodeLabel(const BasicBlock *Node, DOTFuncInfo *) {

    return SimpleNodeLabelString(Node);

  }

  static std::string getCompleteNodeLabel(

      const BasicBlock *Node, DOTFuncInfo *,

      function_ref<void(raw_string_ostream &, const BasicBlock &)>

          HandleBasicBlock = [](raw_string_ostream &OS,

                                const BasicBlock &Node) -> void { OS << Node; },

      function_ref<void(std::string &, unsigned &, unsigned)>

          HandleComment = eraseComment) {

    return CompleteNodeLabelString(Node, HandleBasicBlock, HandleComment);

  }

  std::string getNodeLabel(const BasicBlock *Node, DOTFuncInfo *CFGInfo) {

    if (isSimple())

      return getSimpleNodeLabel(Node, CFGInfo);

    else

      return getCompleteNodeLabel(Node, CFGInfo);

  }

  static std::string getEdgeSourceLabel(const BasicBlock *Node,

                                        const_succ_iterator I) {

    // Label source of conditional branches with "T" or "F"

    if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))

      if (BI->isConditional())

        return (I == succ_begin(Node)) ? "T" : "F";

    // Label source of switch edges with the associated value.

    if (const SwitchInst *SI = dyn_cast<SwitchInst>(Node->getTerminator())) {

      unsigned SuccNo = I.getSuccessorIndex();

      if (SuccNo == 0)

        return "def";

      std::string Str;

      raw_string_ostream OS(Str);

      auto Case = *SwitchInst::ConstCaseIt::fromSuccessorIndex(SI, SuccNo);

      OS << Case.getCaseValue()->getValue();

      return OS.str();

    }

    return "";

  }

  /// Display the raw branch weights from PGO.

  std::string getEdgeAttributes(const BasicBlock *Node, const_succ_iterator I,

                                DOTFuncInfo *CFGInfo) {

    if (!CFGInfo->showEdgeWeights())

      return "";

    const Instruction *TI = Node->getTerminator();

    if (TI->getNumSuccessors() == 1)

      return "penwidth=2";

    unsigned OpNo = I.getSuccessorIndex();

    if (OpNo >= TI->getNumSuccessors())

      return "";

    BasicBlock *SuccBB = TI->getSuccessor(OpNo);

    auto BranchProb = CFGInfo->getBPI()->getEdgeProbability(Node, SuccBB);

    double WeightPercent = ((double)BranchProb.getNumerator()) /

                           ((double)BranchProb.getDenominator());

    double Width = 1 + WeightPercent;

    if (!CFGInfo->useRawEdgeWeights())

      return formatv("label=\"{0:P}\" penwidth={1}", WeightPercent, Width)

          .str();

    // Prepend a 'W' to indicate that this is a weight rather than the actual

    // profile count (due to scaling).

    uint64_t Freq = CFGInfo->getFreq(Node);

    std::string Attrs = formatv("label=\"W:{0}\" penwidth={1}",

                                (uint64_t)(Freq * WeightPercent), Width);

    if (Attrs.size())

      return Attrs;

    MDNode *WeightsNode = getBranchWeightMDNode(*TI);

    if (!WeightsNode)

      return "";

    OpNo = I.getSuccessorIndex() + 1;

    if (OpNo >= WeightsNode->getNumOperands())

      return "";

    ConstantInt *Weight =

        mdconst::dyn_extract<ConstantInt>(WeightsNode->getOperand(OpNo));

    if (!Weight)

      return "";

    return ("label=\"W:" + std::to_string(Weight->getZExtValue()) +

            "\" penwidth=" + std::to_string(Width));

  }

  std::string getNodeAttributes(const BasicBlock *Node, DOTFuncInfo *CFGInfo) {

    if (!CFGInfo->showHeatColors())

      return "";

    uint64_t Freq = CFGInfo->getFreq(Node);

    std::string Color = getHeatColor(Freq, CFGInfo->getMaxFreq());

    std::string EdgeColor = (Freq <= (CFGInfo->getMaxFreq() / 2))

                                ? (getHeatColor(0))

                                : (getHeatColor(1));

    std::string Attrs = "color=\"" + EdgeColor + "ff\", style=filled," +

                        " fillcolor=\"" + Color + "70\"";

    return Attrs;

  }

  bool isNodeHidden(const BasicBlock *Node, const DOTFuncInfo *CFGInfo);

  void computeDeoptOrUnreachablePaths(const Function *F);

};

} // End llvm namespace

namespace llvm {

class FunctionPass;

FunctionPass *createCFGPrinterLegacyPassPass();

FunctionPass *createCFGOnlyPrinterLegacyPassPass();

} // End llvm namespace

#endif