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

   1 //===--- StaticAccessedThroughInstanceCheck.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 "StaticAccessedThroughInstanceCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12 #include "llvm/ADT/StringRef.h"
  13
  14 using namespace clang::ast_matchers;
  15
  16 namespace clang::tidy::readability {
  17
  18 namespace {
  19 AST_MATCHER(CXXMethodDecl, isStatic) { return Node.isStatic(); }
  20 } // namespace
  21
  22 static unsigned getNameSpecifierNestingLevel(const QualType &QType) {
  23   if (const auto *ElType = QType->getAs<ElaboratedType>()) {
  24     if (const NestedNameSpecifier *NestedSpecifiers = ElType->getQualifier()) {
  25       unsigned NameSpecifierNestingLevel = 1;
  26       do {
  27         NameSpecifierNestingLevel++;
  28         NestedSpecifiers = NestedSpecifiers->getPrefix();
  29       } while (NestedSpecifiers);
  30
  31       return NameSpecifierNestingLevel;
  32     }
  33   }
  34   return 0;
  35 }
  36
  37 void StaticAccessedThroughInstanceCheck::storeOptions(
  38     ClangTidyOptions::OptionMap &Opts) {
  39   Options.store(Opts, "NameSpecifierNestingThreshold",
  40                 NameSpecifierNestingThreshold);
  41 }
  42
  43 void StaticAccessedThroughInstanceCheck::registerMatchers(MatchFinder *Finder) {
  44   Finder->addMatcher(
  45       memberExpr(hasDeclaration(anyOf(cxxMethodDecl(isStatic()),
  46                                       varDecl(hasStaticStorageDuration()),
  47                                       enumConstantDecl())))
  48           .bind("memberExpression"),
  49       this);
  50 }
  51
  52 void StaticAccessedThroughInstanceCheck::check(
  53     const MatchFinder::MatchResult &Result) {
  54   const auto *MemberExpression =
  55       Result.Nodes.getNodeAs<MemberExpr>("memberExpression");
  56
  57   if (MemberExpression->getBeginLoc().isMacroID())
  58     return;
  59
  60   const Expr *BaseExpr = MemberExpression->getBase();
  61
  62   // Do not warn for overloaded -> operators.
  63   if (isa<CXXOperatorCallExpr>(BaseExpr))
  64     return;
  65
  66   const QualType BaseType =
  67       BaseExpr->getType()->isPointerType()
  68           ? BaseExpr->getType()->getPointeeType().getUnqualifiedType()
  69           : BaseExpr->getType().getUnqualifiedType();
  70
  71   const ASTContext *AstContext = Result.Context;
  72   PrintingPolicy PrintingPolicyWithSuppressedTag(AstContext->getLangOpts());
  73   PrintingPolicyWithSuppressedTag.SuppressTagKeyword = true;
  74   PrintingPolicyWithSuppressedTag.SuppressUnwrittenScope = true;
  75
  76   PrintingPolicyWithSuppressedTag.PrintCanonicalTypes =
  77       !BaseExpr->getType()->isTypedefNameType();
  78
  79   std::string BaseTypeName =
  80       BaseType.getAsString(PrintingPolicyWithSuppressedTag);
  81
  82   // Ignore anonymous structs/classes which will not have an identifier
  83   const RecordDecl *RecDecl = BaseType->getAsCXXRecordDecl();
  84   if (!RecDecl || RecDecl->getIdentifier() == nullptr)
  85     return;
  86
  87   // Do not warn for CUDA built-in variables.
  88   if (StringRef(BaseTypeName).startswith("__cuda_builtin_"))
  89     return;
  90
  91   SourceLocation MemberExprStartLoc = MemberExpression->getBeginLoc();
  92   auto Diag =
  93       diag(MemberExprStartLoc, "static member accessed through instance");
  94
  95   if (BaseExpr->HasSideEffects(*AstContext) ||
  96       getNameSpecifierNestingLevel(BaseType) > NameSpecifierNestingThreshold)
  97     return;
  98
  99   Diag << FixItHint::CreateReplacement(
 100       CharSourceRange::getCharRange(MemberExprStartLoc,
 101                                     MemberExpression->getMemberLoc()),
 102       BaseTypeName + "::");
 103 }
 104
 105 } // namespace clang::tidy::readability