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 
24 using namespace clang;
25 namespace DOT = llvm::DOT;
26 
27 namespace {
28 class DependencyGraphCallback : public PPCallbacks {
29   const Preprocessor *PP;
30   std::string OutputFile;
31   std::string SysRoot;
32   llvm::SetVector<FileEntryRef> AllFiles;
33   using DependencyMap =
34       llvm::DenseMap<FileEntryRef, SmallVector<FileEntryRef, 2>>;
35 
36   DependencyMap Dependencies;
37 
38 private:
39   raw_ostream &writeNodeReference(raw_ostream &OS,
40                                   const FileEntry *Node);
41   void OutputGraphFile();
42 
43 public:
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,
51                           Optional<FileEntryRef> File, StringRef SearchPath,
52                           StringRef RelativePath, const Module *Imported,
53                           SrcMgr::CharacteristicKind FileType) override;
54 
55   void EndOfMainFile() override {
56     OutputGraphFile();
57   }
58 
59 };
60 }
61 
62 void clang::AttachDependencyGraphGen(Preprocessor &PP, StringRef OutputFile,
63                                      StringRef SysRoot) {
64   PP.addPPCallbacks(std::make_unique<DependencyGraphCallback>(&PP, OutputFile,
65                                                                SysRoot));
66 }
67 
68 void DependencyGraphCallback::InclusionDirective(
69     SourceLocation HashLoc,
70     const Token &IncludeTok,
71     StringRef FileName,
72     bool IsAngled,
73     CharSourceRange FilenameRange,
74     Optional<FileEntryRef> 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   Optional<FileEntryRef> FromFile =
84       SM.getFileEntryRefForID(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 
94 raw_ostream &
95 DependencyGraphCallback::writeNodeReference(raw_ostream &OS,
96                                             const FileEntry *Node) {
97   OS << "header_" << Node->getUID();
98   return OS;
99 }
100 
101 void DependencyGraphCallback::OutputGraphFile() {
102   std::error_code EC;
103   llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_TextWithCRLF);
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(std::string(FileName)) << "\"];\n";
123   }
124 
125   // Write the edges
126   for (DependencyMap::iterator F = Dependencies.begin(),
127                             FEnd = Dependencies.end();
128        F != FEnd; ++F) {
129     for (unsigned I = 0, N = F->second.size(); I != N; ++I) {
130       OS.indent(2);
131       writeNodeReference(OS, F->first);
132       OS << " -> ";
133       writeNodeReference(OS, F->second[I]);
134       OS << ";\n";
135     }
136   }
137   OS << "}\n";
138 }
139 
140