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 {
14 namespace tidy {
15 namespace fuchsia {
16 
17 namespace {
18 AST_MATCHER(Expr, isConstantInitializer) {
19   return Node.isConstantInitializer(Finder->getASTContext(), false);
20 }
21 
22 AST_MATCHER(VarDecl, isGlobalStatic) {
23   return Node.getStorageDuration() == SD_Static && !Node.isLocalVarDecl();
24 }
25 } // namespace
26 
27 void StaticallyConstructedObjectsCheck::registerMatchers(MatchFinder *Finder) {
28   // Constructing global, non-trivial objects with static storage is
29   // disallowed, unless the object is statically initialized with a constexpr
30   // constructor or has no explicit constructor.
31 
32   // Constexpr requires C++11 or later.
33   if (!getLangOpts().CPlusPlus11)
34     return;
35 
36   Finder->addMatcher(varDecl(
37                          // Match global, statically stored objects...
38                          isGlobalStatic(),
39                          // ... that have C++ constructors...
40                          hasDescendant(cxxConstructExpr(unless(allOf(
41                              // ... unless it is constexpr ...
42                              hasDeclaration(cxxConstructorDecl(isConstexpr())),
43                              // ... and is statically initialized.
44                              isConstantInitializer())))))
45                          .bind("decl"),
46                      this);
47 }
48 
49 void StaticallyConstructedObjectsCheck::check(
50     const MatchFinder::MatchResult &Result) {
51   if (const auto *D = Result.Nodes.getNodeAs<VarDecl>("decl"))
52     diag(D->getBeginLoc(), "static objects are disallowed; if possible, use a "
53                            "constexpr constructor instead");
54 }
55 
56 } // namespace fuchsia
57 } // namespace tidy
58 } // namespace clang
59