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