clang/lib/Frontend/DependencyGraph.cpp

   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 *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, const Token &IncludeTok, StringRef FileName,
  70     bool IsAngled, CharSourceRange FilenameRange, OptionalFileEntryRef File,
  71     StringRef SearchPath, StringRef RelativePath, const Module *Imported,
  72     SrcMgr::CharacteristicKind FileType) {
  73   if (!File)
  74     return;
  75
  76   SourceManager &SM = PP->getSourceManager();
  77   OptionalFileEntryRef FromFile =
  78       SM.getFileEntryRefForID(SM.getFileID(SM.getExpansionLoc(HashLoc)));
  79   if (!FromFile)
  80     return;
  81
  82   Dependencies[*FromFile].push_back(*File);
  83
  84   AllFiles.insert(*File);
  85   AllFiles.insert(*FromFile);
  86 }
  87
  88 raw_ostream &
  89 DependencyGraphCallback::writeNodeReference(raw_ostream &OS,
  90                                             const FileEntry *Node) {
  91   OS << "header_" << Node->getUID();
  92   return OS;
  93 }
  94
  95 void DependencyGraphCallback::OutputGraphFile() {
  96   std::error_code EC;
  97   llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_TextWithCRLF);
  98   if (EC) {
  99     PP->getDiagnostics().Report(diag::err_fe_error_opening) << OutputFile
 100                                                             << EC.message();
 101     return;
 102   }
 103
 104   OS << "digraph \"dependencies\" {\n";
 105
 106   // Write the nodes
 107   for (unsigned I = 0, N = AllFiles.size(); I != N; ++I) {
 108     // Write the node itself.
 109     OS.indent(2);
 110     writeNodeReference(OS, AllFiles[I]);
 111     OS << " [ shape=\"box\", label=\"";
 112     StringRef FileName = AllFiles[I].getName();
 113     if (FileName.startswith(SysRoot))
 114       FileName = FileName.substr(SysRoot.size());
 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