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                           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