clang-tools-extra/clang-tidy/fuchsia/StaticallyConstructedObjectsCheck.cpp

   1 //===--- StaticallyConstructedObjectsCheck.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 "StaticallyConstructedObjectsCheck.h"
  10
  11 using namespace clang::ast_matchers;
  12
  13 namespace clang::tidy::fuchsia {
  14
  15 namespace {
  16 AST_MATCHER(Expr, isConstantInitializer) {
  17   return Node.isConstantInitializer(Finder->getASTContext(), false);
  18 }
  19
  20 AST_MATCHER(VarDecl, isGlobalStatic) {
  21   return Node.getStorageDuration() == SD_Static && !Node.isLocalVarDecl();
  22 }
  23 } // namespace
  24
  25 void StaticallyConstructedObjectsCheck::registerMatchers(MatchFinder *Finder) {
  26   // Constructing global, non-trivial objects with static storage is
  27   // disallowed, unless the object is statically initialized with a constexpr
  28   // constructor or has no explicit constructor.
  29   Finder->addMatcher(
  30       traverse(TK_AsIs,
  31                varDecl(
  32                    // Match global, statically stored objects...
  33                    isGlobalStatic(),
  34                    // ... that have C++ constructors...
  35                    hasDescendant(cxxConstructExpr(unless(allOf(
  36                        // ... unless it is constexpr ...
  37                        hasDeclaration(cxxConstructorDecl(isConstexpr())),
  38                        // ... and is statically initialized.
  39                        isConstantInitializer())))))
  40                    .bind("decl")),
  41       this);
  42 }
  43
  44 void StaticallyConstructedObjectsCheck::check(
  45     const MatchFinder::MatchResult &Result) {
  46   if (const auto *D = Result.Nodes.getNodeAs<VarDecl>("decl"))
  47     diag(D->getBeginLoc(), "static objects are disallowed; if possible, use a "
  48                            "constexpr constructor instead");
  49 }
  50
  51 } // namespace clang::tidy::fuchsia