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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/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/Support/GraphWriter.h"
namespace llvm {
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);
};
template<>
struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
static std::string getGraphName(const Function *F) {
return "CFG for '" + F->getName().str() + "' function";
}
static std::string getSimpleNodeLabel(const BasicBlock *Node,
const Function *) {
if (!Node->getName().empty())
return Node->getName().str();
std::string Str;
raw_string_ostream OS(Str);
Node->printAsOperand(OS, false);
return OS.str();
}
static std::string getCompleteNodeLabel(const BasicBlock *Node,
const Function *) {
enum { MaxColumns = 80 };
std::string Str;
raw_string_ostream OS(Str);
if (Node->getName().empty()) {
Node->printAsOperand(OS, false);
OS << ":";
}
OS << *Node;
std::string OutStr = OS.str();
if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
// Process string output to make it nicer...
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
OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
--i;
} 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;
}
std::string getNodeLabel(const BasicBlock *Node,
const Function *Graph) {
if (isSimple())
return getSimpleNodeLabel(Node, Graph);
else
return getCompleteNodeLabel(Node, Graph);
}
static std::string getEdgeSourceLabel(const BasicBlock *Node,
succ_const_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, succ_const_iterator I,
const Function *F) {
const Instruction *TI = Node->getTerminator();
if (TI->getNumSuccessors() == 1)
return "";
MDNode *WeightsNode = TI->getMetadata(LLVMContext::MD_prof);
if (!WeightsNode)
return "";
MDString *MDName = cast<MDString>(WeightsNode->getOperand(0));
if (MDName->getString() != "branch_weights")
return "";
unsigned OpNo = I.getSuccessorIndex() + 1;
if (OpNo >= WeightsNode->getNumOperands())
return "";
ConstantInt *Weight =
mdconst::dyn_extract<ConstantInt>(WeightsNode->getOperand(OpNo));
if (!Weight)
return "";
// Prepend a 'W' to indicate that this is a weight rather than the actual
// profile count (due to scaling).
return ("label=\"W:" + Twine(Weight->getZExtValue()) + "\"").str();
}
};
} // End llvm namespace
namespace llvm {
class FunctionPass;
FunctionPass *createCFGPrinterLegacyPassPass ();
FunctionPass *createCFGOnlyPrinterLegacyPassPass ();
} // End llvm namespace
#endif