clang-tools-extra/clang-tidy/bugprone/DynamicStaticInitializersCheck.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "DynamicStaticInitializersCheck.h"
#include "../utils/FileExtensionsUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"

using namespace clang::ast_matchers;

namespace clang::tidy::bugprone {

namespace {

AST_MATCHER(VarDecl, hasConstantDeclaration) {
  if (Node.isConstexpr() || Node.hasAttr<ConstInitAttr>())
    return true;
  if (const VarDecl *Def = Node.getDefinition();
      Def && (Def->isConstexpr() || Def->hasAttr<ConstInitAttr>()))
    return true;
  const Expr *Init = Node.getInit();
  if (Init && !Init->isValueDependent())
    return Node.evaluateValue();
  return false;
}

} // namespace

DynamicStaticInitializersCheck::DynamicStaticInitializersCheck(
    StringRef Name, ClangTidyContext *Context)
    : ClangTidyCheck(Name, Context) {}

void DynamicStaticInitializersCheck::registerMatchers(MatchFinder *Finder) {
  Finder->addMatcher(
      varDecl(hasGlobalStorage(), unless(hasConstantDeclaration())).bind("var"),
      this);
}

void DynamicStaticInitializersCheck::check(
    const MatchFinder::MatchResult &Result) {
  const auto *Var = Result.Nodes.getNodeAs<VarDecl>("var");
  const SourceLocation Loc = Var->getLocation();
  if (!Loc.isValid() ||
      !utils::isPresumedLocInHeaderFile(Loc, *Result.SourceManager,
                                        getHeaderFileExtensions()))
    return;
  // If the initializer is a constant expression, then the compiler
  // doesn't have to dynamically initialize it.
  diag(Loc,
       "static variable %0 may be dynamically initialized in this header file")
      << Var;
}

} // namespace clang::tidy::bugprone