clang-tools-extra/clang-tidy/google/GlobalNamesInHeadersCheck.cpp

   1 //===--- GlobalNamesInHeadersCheck.cpp - clang-tidy -----------------*- C++ -*-===//
   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 "GlobalNamesInHeadersCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12 #include "clang/ASTMatchers/ASTMatchers.h"
  13 #include "clang/Lex/Lexer.h"
  14
  15 using namespace clang::ast_matchers;
  16
  17 namespace clang::tidy::google::readability {
  18
  19 GlobalNamesInHeadersCheck::GlobalNamesInHeadersCheck(StringRef Name,
  20                                                      ClangTidyContext *Context)
  21     : ClangTidyCheck(Name, Context),
  22       HeaderFileExtensions(Context->getHeaderFileExtensions()) {}
  23
  24 void GlobalNamesInHeadersCheck::registerMatchers(
  25     ast_matchers::MatchFinder *Finder) {
  26   Finder->addMatcher(decl(anyOf(usingDecl(), usingDirectiveDecl()),
  27                           hasDeclContext(translationUnitDecl()))
  28                          .bind("using_decl"),
  29                      this);
  30 }
  31
  32 void GlobalNamesInHeadersCheck::check(const MatchFinder::MatchResult &Result) {
  33   const auto *D = Result.Nodes.getNodeAs<Decl>("using_decl");
  34   // If it comes from a macro, we'll assume it is fine.
  35   if (D->getBeginLoc().isMacroID())
  36     return;
  37
  38   // Ignore if it comes from the "main" file ...
  39   if (Result.SourceManager->isInMainFile(
  40           Result.SourceManager->getExpansionLoc(D->getBeginLoc()))) {
  41     // unless that file is a header.
  42     if (!utils::isSpellingLocInHeaderFile(
  43             D->getBeginLoc(), *Result.SourceManager, HeaderFileExtensions))
  44       return;
  45   }
  46
  47   if (const auto *UsingDirective = dyn_cast<UsingDirectiveDecl>(D)) {
  48     if (UsingDirective->getNominatedNamespace()->isAnonymousNamespace()) {
  49       // Anonymous namespaces inject a using directive into the AST to import
  50       // the names into the containing namespace.
  51       // We should not have them in headers, but there is another warning for
  52       // that.
  53       return;
  54     }
  55   }
  56
  57   diag(D->getBeginLoc(),
  58        "using declarations in the global namespace in headers are prohibited");
  59 }
  60
  61 } // namespace clang::tidy::google::readability