1//===--- AvoidNonConstGlobalVariablesCheck.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 "AvoidNonConstGlobalVariablesCheck.h"
10#include "clang/ASTMatchers/ASTMatchFinder.h"
11#include "clang/ASTMatchers/ASTMatchers.h"
12
13using namespace clang::ast_matchers;
14
15namespace clang::tidy::cppcoreguidelines {
16
17AvoidNonConstGlobalVariablesCheck::AvoidNonConstGlobalVariablesCheck(
18 StringRef Name, ClangTidyContext *Context)
19 : ClangTidyCheck(Name, Context),
20 AllowInternalLinkage(Options.get(LocalName: "AllowInternalLinkage", Default: false)) {}
21
22void AvoidNonConstGlobalVariablesCheck::registerMatchers(MatchFinder *Finder) {
23 auto NamespaceMatcher = AllowInternalLinkage
24 ? namespaceDecl(unless(isAnonymous()))
25 : namespaceDecl();
26 auto GlobalContext =
27 varDecl(hasGlobalStorage(),
28 hasDeclContext(InnerMatcher: anyOf(NamespaceMatcher, translationUnitDecl())));
29
30 auto GlobalVariable = varDecl(
31 GlobalContext,
32 AllowInternalLinkage ? varDecl(unless(isStaticStorageClass()))
33 : varDecl(),
34 unless(anyOf(
35 isConstexpr(), hasType(InnerMatcher: isConstQualified()),
36 hasType(InnerMatcher: referenceType())))); // References can't be changed, only the
37 // data they reference can be changed.
38
39 auto GlobalReferenceToNonConst =
40 varDecl(GlobalContext, hasType(InnerMatcher: referenceType()),
41 unless(hasType(InnerMatcher: references(InnerMatcher: qualType(isConstQualified())))));
42
43 auto GlobalPointerToNonConst = varDecl(
44 GlobalContext, hasType(InnerMatcher: pointerType(pointee(unless(isConstQualified())))));
45
46 Finder->addMatcher(NodeMatch: GlobalVariable.bind(ID: "non-const_variable"), Action: this);
47 Finder->addMatcher(NodeMatch: GlobalReferenceToNonConst.bind(ID: "indirection_to_non-const"),
48 Action: this);
49 Finder->addMatcher(NodeMatch: GlobalPointerToNonConst.bind(ID: "indirection_to_non-const"),
50 Action: this);
51}
52
53void AvoidNonConstGlobalVariablesCheck::check(
54 const MatchFinder::MatchResult &Result) {
55 if (const auto *Variable =
56 Result.Nodes.getNodeAs<VarDecl>(ID: "non-const_variable")) {
57 diag(Variable->getLocation(), "variable %0 is non-const and globally "
58 "accessible, consider making it const")
59 << Variable; // FIXME: Add fix-it hint to Variable
60 // Don't return early, a non-const variable may also be a pointer or
61 // reference to non-const data.
62 }
63
64 if (const auto *VD =
65 Result.Nodes.getNodeAs<VarDecl>(ID: "indirection_to_non-const")) {
66 diag(VD->getLocation(),
67 "variable %0 provides global access to a non-const object; consider "
68 "making the %select{referenced|pointed-to}1 data 'const'")
69 << VD
70 << VD->getType()->isPointerType(); // FIXME: Add fix-it hint to Variable
71 }
72}
73
74void AvoidNonConstGlobalVariablesCheck::storeOptions(
75 ClangTidyOptions::OptionMap &Opts) {
76 Options.store(Options&: Opts, LocalName: "AllowInternalLinkage", Value: AllowInternalLinkage);
77}
78
79} // namespace clang::tidy::cppcoreguidelines
80

source code of clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidNonConstGlobalVariablesCheck.cpp