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
23 using namespace llvm;
24
25 #define DEBUG_TYPE "dot-machine-cfg"
26
27 static 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
32 static 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
36 static cl::opt<bool>
37 CFGOnly("dot-mcfg-only", cl::init(false), cl::Hidden,
38 cl::desc("Print only the CFG without blocks body"));
39
writeMCFGToDotFile(MachineFunction & MF)40 static 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
57 namespace {
58
59 class MachineCFGPrinter : public MachineFunctionPass {
60 public:
61 static char ID;
62
63 MachineCFGPrinter();
64
65 bool runOnMachineFunction(MachineFunction &MF) override;
66
getAnalysisUsage(AnalysisUsage & AU) const67 void getAnalysisUsage(AnalysisUsage &AU) const override {
68 AU.setPreservesCFG();
69 MachineFunctionPass::getAnalysisUsage(AU);
70 }
71 };
72
73 } // namespace
74
75 char MachineCFGPrinter::ID = 0;
76
77 char &llvm::MachineCFGPrinterID = MachineCFGPrinter::ID;
78
79 INITIALIZE_PASS(MachineCFGPrinter, DEBUG_TYPE, "Machine CFG Printer Pass",
80 false, true)
81
82 /// Default construct and initialize the pass.
MachineCFGPrinter()83 MachineCFGPrinter::MachineCFGPrinter() : MachineFunctionPass(ID) {
84 initializeMachineCFGPrinterPass(*PassRegistry::getPassRegistry());
85 }
86
runOnMachineFunction(MachineFunction & MF)87 bool 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