1//===- MachineCFGPrinter.cpp - DOT Printer for Machine Functions ----------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//===----------------------------------------------------------------------===//
9//
10// This file defines the `-dot-machine-cfg` analysis pass, which emits
11// Machine Function in DOT format in file titled `<prefix>.<function-name>.dot.
12//===----------------------------------------------------------------------===//
13
14#include "llvm/CodeGen/MachineCFGPrinter.h"
15#include "llvm/CodeGen/MachineBasicBlock.h"
16#include "llvm/CodeGen/MachineFunctionPass.h"
17#include "llvm/CodeGen/TargetSubtargetInfo.h"
18#include "llvm/InitializePasses.h"
19#include "llvm/Pass.h"
20#include "llvm/PassRegistry.h"
21#include "llvm/Support/GraphWriter.h"
22
23using namespace llvm;
24
25#define DEBUG_TYPE "dot-machine-cfg"
26
27static cl::opt<std::string>
28    MCFGFuncName("mcfg-func-name", cl::Hidden,
29                 cl::desc("The name of a function (or its substring)"
30                          " whose CFG is viewed/printed."));
31
32static cl::opt<std::string> MCFGDotFilenamePrefix(
33    "mcfg-dot-filename-prefix", cl::Hidden,
34    cl::desc("The prefix used for the Machine CFG dot file names."));
35
36static cl::opt<bool>
37    CFGOnly("dot-mcfg-only", cl::init(false), cl::Hidden,
38            cl::desc("Print only the CFG without blocks body"));
39
40static void writeMCFGToDotFile(MachineFunction &MF) {
41  std::string Filename =
42      (MCFGDotFilenamePrefix + "." + MF.getName() + ".dot").str();
43  errs() << "Writing '" << Filename << "'...";
44
45  std::error_code EC;
46  raw_fd_ostream File(Filename, EC, sys::fs::OF_Text);
47
48  DOTMachineFuncInfo MCFGInfo(&MF);
49
50  if (!EC)
51    WriteGraph(File, &MCFGInfo, CFGOnly);
52  else
53    errs() << "  error opening file for writing!";
54  errs() << '\n';
55}
56
57namespace {
58
59class MachineCFGPrinter : public MachineFunctionPass {
60public:
61  static char ID;
62
63  MachineCFGPrinter();
64
65  bool runOnMachineFunction(MachineFunction &MF) override;
66
67  void getAnalysisUsage(AnalysisUsage &AU) const override {
68    AU.setPreservesCFG();
69    MachineFunctionPass::getAnalysisUsage(AU);
70  }
71};
72
73} // namespace
74
75char MachineCFGPrinter::ID = 0;
76
77char &llvm::MachineCFGPrinterID = MachineCFGPrinter::ID;
78
79INITIALIZE_PASS(MachineCFGPrinter, DEBUG_TYPE, "Machine CFG Printer Pass",
80                false, true)
81
82/// Default construct and initialize the pass.
83MachineCFGPrinter::MachineCFGPrinter() : MachineFunctionPass(ID) {
84  initializeMachineCFGPrinterPass(*PassRegistry::getPassRegistry());
85}
86
87bool MachineCFGPrinter::runOnMachineFunction(MachineFunction &MF) {
88  if (!MCFGFuncName.empty() && !MF.getName().contains(MCFGFuncName))
89    return false;
90  errs() << "Writing Machine CFG for function ";
91  errs().write_escaped(MF.getName()) << '\n';
92
93  writeMCFGToDotFile(MF);
94  return false;
95}
96