clang-tools-extra/clang-tidy/readability/DuplicateIncludeCheck.cpp

   1 //===--- DuplicateIncludeCheck.cpp - clang-tidy ---------------------------===//
   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 #include "DuplicateIncludeCheck.h"
  10 #include "clang/Frontend/CompilerInstance.h"
  11 #include "clang/Lex/Preprocessor.h"
  12 #include "llvm/ADT/STLExtras.h"
  13 #include "llvm/ADT/SmallVector.h"
  14 #include <memory>
  15
  16 namespace clang::tidy::readability {
  17
  18 static SourceLocation advanceBeyondCurrentLine(const SourceManager &SM,
  19                                                SourceLocation Start,
  20                                                int Offset) {
  21   const FileID Id = SM.getFileID(Start);
  22   const unsigned LineNumber = SM.getSpellingLineNumber(Start);
  23   while (SM.getFileID(Start) == Id &&
  24          SM.getSpellingLineNumber(Start.getLocWithOffset(Offset)) == LineNumber)
  25     Start = Start.getLocWithOffset(Offset);
  26   return Start;
  27 }
  28
  29 namespace {
  30
  31 using FileList = SmallVector<StringRef>;
  32
  33 class DuplicateIncludeCallbacks : public PPCallbacks {
  34 public:
  35   DuplicateIncludeCallbacks(DuplicateIncludeCheck &Check,
  36                             const SourceManager &SM)
  37       : Check(Check), SM(SM) {
  38     // The main file doesn't participate in the FileChanged notification.
  39     Files.emplace_back();
  40   }
  41
  42   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
  43                    SrcMgr::CharacteristicKind FileType,
  44                    FileID PrevFID) override;
  45
  46   void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
  47                           StringRef FileName, bool IsAngled,
  48                           CharSourceRange FilenameRange,
  49                           OptionalFileEntryRef File, StringRef SearchPath,
  50                           StringRef RelativePath, const Module *SuggestedModule,
  51                           bool ModuleImported,
  52                           SrcMgr::CharacteristicKind FileType) override;
  53
  54   void MacroDefined(const Token &MacroNameTok,
  55                     const MacroDirective *MD) override;
  56
  57   void MacroUndefined(const Token &MacroNameTok, const MacroDefinition &MD,
  58                       const MacroDirective *Undef) override;
  59
  60 private:
  61   // A list of included files is kept for each file we enter.
  62   SmallVector<FileList> Files;
  63   DuplicateIncludeCheck &Check;
  64   const SourceManager &SM;
  65 };
  66
  67 void DuplicateIncludeCallbacks::FileChanged(SourceLocation Loc,
  68                                             FileChangeReason Reason,
  69                                             SrcMgr::CharacteristicKind FileType,
  70                                             FileID PrevFID) {
  71   if (Reason == EnterFile)
  72     Files.emplace_back();
  73   else if (Reason == ExitFile)
  74     Files.pop_back();
  75 }
  76
  77 void DuplicateIncludeCallbacks::InclusionDirective(
  78     SourceLocation HashLoc, const Token &IncludeTok, StringRef FileName,
  79     bool IsAngled, CharSourceRange FilenameRange, OptionalFileEntryRef File,
  80     StringRef SearchPath, StringRef RelativePath, const Module *SuggestedModule,
  81     bool ModuleImported, SrcMgr::CharacteristicKind FileType) {
  82   // Skip includes behind macros
  83   if (FilenameRange.getBegin().isMacroID() ||
  84       FilenameRange.getEnd().isMacroID())
  85     return;
  86   if (llvm::is_contained(Files.back(), FileName)) {
  87     // We want to delete the entire line, so make sure that [Start,End] covers
  88     // everything.
  89     SourceLocation Start =
  90         advanceBeyondCurrentLine(SM, HashLoc, -1).getLocWithOffset(-1);
  91     SourceLocation End =
  92         advanceBeyondCurrentLine(SM, FilenameRange.getEnd(), 1);
  93     Check.diag(HashLoc, "duplicate include")
  94         << FixItHint::CreateRemoval(SourceRange{Start, End});
  95   } else
  96     Files.back().push_back(FileName);
  97 }
  98
  99 void DuplicateIncludeCallbacks::MacroDefined(const Token &MacroNameTok,
 100                                              const MacroDirective *MD) {
 101   Files.back().clear();
 102 }
 103
 104 void DuplicateIncludeCallbacks::MacroUndefined(const Token &MacroNameTok,
 105                                                const MacroDefinition &MD,
 106                                                const MacroDirective *Undef) {
 107   Files.back().clear();
 108 }
 109
 110 } // namespace
 111
 112 void DuplicateIncludeCheck::registerPPCallbacks(
 113     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
 114   PP->addPPCallbacks(std::make_unique<DuplicateIncludeCallbacks>(*this, SM));
 115 }
 116
 117 } // namespace clang::tidy::readability