xref: /llvm-project/clang/lib/Frontend/DependencyGraph.cpp (revision da95d926f6fce4ed9707c77908ad96624268f134)
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                           OptionalFileEntryRef File, StringRef SearchPath,
52                           StringRef RelativePath, const Module *SuggestedModule,
53                           bool ModuleImported,
54                           SrcMgr::CharacteristicKind FileType) override;
55 
56   void EndOfMainFile() override {
57     OutputGraphFile();
58   }
59 
60 };
61 }
62 
63 void clang::AttachDependencyGraphGen(Preprocessor &PP, StringRef OutputFile,
64                                      StringRef SysRoot) {
65   PP.addPPCallbacks(std::make_unique<DependencyGraphCallback>(&PP, OutputFile,
66                                                                SysRoot));
67 }
68 
69 void DependencyGraphCallback::InclusionDirective(
70     SourceLocation HashLoc, const Token &IncludeTok, StringRef FileName,
71     bool IsAngled, CharSourceRange FilenameRange, OptionalFileEntryRef File,
72     StringRef SearchPath, StringRef RelativePath, const Module *SuggestedModule,
73     bool ModuleImported, SrcMgr::CharacteristicKind FileType) {
74   if (!File)
75     return;
76 
77   SourceManager &SM = PP->getSourceManager();
78   OptionalFileEntryRef FromFile =
79       SM.getFileEntryRefForID(SM.getFileID(SM.getExpansionLoc(HashLoc)));
80   if (!FromFile)
81     return;
82 
83   Dependencies[*FromFile].push_back(*File);
84 
85   AllFiles.insert(*File);
86   AllFiles.insert(*FromFile);
87 }
88 
89 raw_ostream &
90 DependencyGraphCallback::writeNodeReference(raw_ostream &OS,
91                                             const FileEntry *Node) {
92   OS << "header_" << Node->getUID();
93   return OS;
94 }
95 
96 void DependencyGraphCallback::OutputGraphFile() {
97   std::error_code EC;
98   llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_TextWithCRLF);
99   if (EC) {
100     PP->getDiagnostics().Report(diag::err_fe_error_opening) << OutputFile
101                                                             << EC.message();
102     return;
103   }
104 
105   OS << "digraph \"dependencies\" {\n";
106 
107   // Write the nodes
108   for (unsigned I = 0, N = AllFiles.size(); I != N; ++I) {
109     // Write the node itself.
110     OS.indent(2);
111     writeNodeReference(OS, AllFiles[I]);
112     OS << " [ shape=\"box\", label=\"";
113     StringRef FileName = AllFiles[I].getName();
114     FileName.consume_front(SysRoot);
115 
116     OS << DOT::EscapeString(std::string(FileName)) << "\"];\n";
117   }
118 
119   // Write the edges
120   for (DependencyMap::iterator F = Dependencies.begin(),
121                             FEnd = Dependencies.end();
122        F != FEnd; ++F) {
123     for (unsigned I = 0, N = F->second.size(); I != N; ++I) {
124       OS.indent(2);
125       writeNodeReference(OS, F->first);
126       OS << " -> ";
127       writeNodeReference(OS, F->second[I]);
128       OS << ";\n";
129     }
130   }
131   OS << "}\n";
132 }
133 
134