DependencyGraph.cpp revision 360784 
1//===--- DependencyGraph.cpp - Generate dependency file -------------------===//
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// This code generates a header dependency graph in DOT format, for use
10// with, e.g., GraphViz.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Frontend/Utils.h"
15#include "clang/Basic/FileManager.h"
16#include "clang/Basic/SourceManager.h"
17#include "clang/Frontend/FrontendDiagnostic.h"
18#include "clang/Lex/PPCallbacks.h"
19#include "clang/Lex/Preprocessor.h"
20#include "llvm/ADT/SetVector.h"
21#include "llvm/Support/GraphWriter.h"
22#include "llvm/Support/raw_ostream.h"
23
24using namespace clang;
25namespace DOT = llvm::DOT;
26
27namespace {
28class DependencyGraphCallback : public PPCallbacks {
29  const Preprocessor *PP;
30  std::string OutputFile;
31  std::string SysRoot;
32  llvm::SetVector<const FileEntry *> AllFiles;
33  typedef llvm::DenseMap<const FileEntry *,
34                         SmallVector<const FileEntry *, 2> > DependencyMap;
35
36  DependencyMap Dependencies;
37
38private:
39  raw_ostream &writeNodeReference(raw_ostream &OS,
40                                  const FileEntry *Node);
41  void OutputGraphFile();
42
43public:
44  DependencyGraphCallback(const Preprocessor *_PP, StringRef OutputFile,
45                          StringRef SysRoot)
46    : PP(_PP), OutputFile(OutputFile.str()), SysRoot(SysRoot.str()) { }
47
48  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
49                          StringRef FileName, bool IsAngled,
50                          CharSourceRange FilenameRange, const FileEntry *File,
51                          StringRef SearchPath, StringRef RelativePath,
52                          const Module *Imported,
53                          SrcMgr::CharacteristicKind FileType) override;
54
55  void EndOfMainFile() override {
56    OutputGraphFile();
57  }
58
59};
60}
61
62void clang::AttachDependencyGraphGen(Preprocessor &PP, StringRef OutputFile,
63                                     StringRef SysRoot) {
64  PP.addPPCallbacks(std::make_unique<DependencyGraphCallback>(&PP, OutputFile,
65                                                               SysRoot));
66}
67
68void DependencyGraphCallback::InclusionDirective(
69    SourceLocation HashLoc,
70    const Token &IncludeTok,
71    StringRef FileName,
72    bool IsAngled,
73    CharSourceRange FilenameRange,
74    const FileEntry *File,
75    StringRef SearchPath,
76    StringRef RelativePath,
77    const Module *Imported,
78    SrcMgr::CharacteristicKind FileType) {
79  if (!File)
80    return;
81
82  SourceManager &SM = PP->getSourceManager();
83  const FileEntry *FromFile
84    = SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(HashLoc)));
85  if (!FromFile)
86    return;
87
88  Dependencies[FromFile].push_back(File);
89
90  AllFiles.insert(File);
91  AllFiles.insert(FromFile);
92}
93
94raw_ostream &
95DependencyGraphCallback::writeNodeReference(raw_ostream &OS,
96                                            const FileEntry *Node) {
97  OS << "header_" << Node->getUID();
98  return OS;
99}
100
101void DependencyGraphCallback::OutputGraphFile() {
102  std::error_code EC;
103  llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_Text);
104  if (EC) {
105    PP->getDiagnostics().Report(diag::err_fe_error_opening) << OutputFile
106                                                            << EC.message();
107    return;
108  }
109
110  OS << "digraph \"dependencies\" {\n";
111
112  // Write the nodes
113  for (unsigned I = 0, N = AllFiles.size(); I != N; ++I) {
114    // Write the node itself.
115    OS.indent(2);
116    writeNodeReference(OS, AllFiles[I]);
117    OS << " [ shape=\"box\", label=\"";
118    StringRef FileName = AllFiles[I]->getName();
119    if (FileName.startswith(SysRoot))
120      FileName = FileName.substr(SysRoot.size());
121
122    OS << DOT::EscapeString(FileName)
123    << "\"];\n";
124  }
125
126  // Write the edges
127  for (DependencyMap::iterator F = Dependencies.begin(),
128                            FEnd = Dependencies.end();
129       F != FEnd; ++F) {
130    for (unsigned I = 0, N = F->second.size(); I != N; ++I) {
131      OS.indent(2);
132      writeNodeReference(OS, F->first);
133      OS << " -> ";
134      writeNodeReference(OS, F->second[I]);
135      OS << ";\n";
136    }
137  }
138  OS << "}\n";
139}
140
141