1 //===--- GlobalVariableDeclarationCheck.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 "GlobalVariableDeclarationCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "llvm/ADT/StringExtras.h"
13 #include "llvm/ADT/StringRef.h"
14
15 #include <string>
16
17 using namespace clang::ast_matchers;
18
19 namespace clang::tidy::google::objc {
20
21 namespace {
22
AST_MATCHER(VarDecl,isLocalVariable)23 AST_MATCHER(VarDecl, isLocalVariable) { return Node.isLocalVarDecl(); }
24
generateFixItHint(const VarDecl * Decl,bool IsConst)25 FixItHint generateFixItHint(const VarDecl *Decl, bool IsConst) {
26 if (IsConst && (Decl->getStorageClass() != SC_Static)) {
27 // No fix available if it is not a static constant, since it is difficult
28 // to determine the proper fix in this case.
29 return {};
30 }
31
32 char FC = Decl->getName()[0];
33 if (!llvm::isAlpha(FC) || Decl->getName().size() == 1) {
34 // No fix available if first character is not alphabetical character, or it
35 // is a single-character variable, since it is difficult to determine the
36 // proper fix in this case. Users should create a proper variable name by
37 // their own.
38 return {};
39 }
40 char SC = Decl->getName()[1];
41 if ((FC == 'k' || FC == 'g') && !llvm::isAlpha(SC)) {
42 // No fix available if the prefix is correct but the second character is
43 // not alphabetical, since it is difficult to determine the proper fix in
44 // this case.
45 return {};
46 }
47
48 auto NewName = (IsConst ? "k" : "g") +
49 llvm::StringRef(std::string(1, FC)).upper() +
50 Decl->getName().substr(1).str();
51
52 return FixItHint::CreateReplacement(
53 CharSourceRange::getTokenRange(SourceRange(Decl->getLocation())),
54 llvm::StringRef(NewName));
55 }
56 } // namespace
57
registerMatchers(MatchFinder * Finder)58 void GlobalVariableDeclarationCheck::registerMatchers(MatchFinder *Finder) {
59 // need to add two matchers since we need to bind different ids to distinguish
60 // constants and variables. Since bind() can only be called on node matchers,
61 // we cannot make it in one matcher.
62 //
63 // Note that hasGlobalStorage() matches static variables declared locally
64 // inside a function or method, so we need to exclude those with
65 // isLocalVariable().
66 Finder->addMatcher(
67 varDecl(hasGlobalStorage(), unless(hasType(isConstQualified())),
68 unless(isLocalVariable()), unless(matchesName("::g[A-Z]")))
69 .bind("global_var"),
70 this);
71 Finder->addMatcher(varDecl(hasGlobalStorage(), hasType(isConstQualified()),
72 unless(isLocalVariable()),
73 unless(matchesName("::(k[A-Z])|([A-Z][A-Z0-9])")))
74 .bind("global_const"),
75 this);
76 }
77
check(const MatchFinder::MatchResult & Result)78 void GlobalVariableDeclarationCheck::check(
79 const MatchFinder::MatchResult &Result) {
80 if (const auto *Decl = Result.Nodes.getNodeAs<VarDecl>("global_var")) {
81 if (Decl->isStaticDataMember())
82 return;
83 diag(Decl->getLocation(),
84 "non-const global variable '%0' must have a name which starts with "
85 "'g[A-Z]'")
86 << Decl->getName() << generateFixItHint(Decl, false);
87 }
88 if (const auto *Decl = Result.Nodes.getNodeAs<VarDecl>("global_const")) {
89 if (Decl->isStaticDataMember())
90 return;
91 diag(Decl->getLocation(),
92 "const global variable '%0' must have a name which starts with "
93 "an appropriate prefix")
94 << Decl->getName() << generateFixItHint(Decl, true);
95 }
96 }
97
98 } // namespace clang::tidy::google::objc
99