clang-tools 10.0.0

StringCompareCheck.cpp
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1 //===-- StringCompareCheck.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 "StringCompareCheck.h"
10 #include "../utils/FixItHintUtils.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Tooling/FixIt.h"
14
15 using namespace clang::ast_matchers;
16
17 namespace clang {
18 namespace tidy {
19 namespace readability {
20
21 static const StringRef CompareMessage = "do not use 'compare' to test equality "
22 "of strings; use the string equality "
23 "operator instead";
24
25 void StringCompareCheck::registerMatchers(MatchFinder *Finder) {
26 if (!getLangOpts().CPlusPlus)
27 return;
28
29 const auto StrCompare = cxxMemberCallExpr(
30 callee(cxxMethodDecl(hasName("compare"),
31 ofClass(classTemplateSpecializationDecl(
32 hasName("::std::basic_string"))))),
33 hasArgument(0, expr().bind("str2")), argumentCountIs(1),
34 callee(memberExpr().bind("str1")));
35
36 // First and second case: cast str.compare(str) to boolean.
37 Finder->addMatcher(implicitCastExpr(hasImplicitDestinationType(booleanType()),
38 has(StrCompare))
39 .bind("match1"),
40 this);
41
42 // Third and fourth case: str.compare(str) == 0 and str.compare(str) != 0.
43 Finder->addMatcher(
44 binaryOperator(anyOf(hasOperatorName("=="), hasOperatorName("!=")),
45 hasEitherOperand(StrCompare.bind("compare")),
46 hasEitherOperand(integerLiteral(equals(0)).bind("zero")))
47 .bind("match2"),
48 this);
49 }
50
51 void StringCompareCheck::check(const MatchFinder::MatchResult &Result) {
52 if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>("match1")) {
53 diag(Matched->getBeginLoc(), CompareMessage);
54 return;
55 }
56
57 if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>("match2")) {
58 const ASTContext &Ctx = *Result.Context;
59
60 if (const auto *Zero = Result.Nodes.getNodeAs<Stmt>("zero")) {
61 const auto *Str1 = Result.Nodes.getNodeAs<MemberExpr>("str1");
62 const auto *Str2 = Result.Nodes.getNodeAs<Stmt>("str2");
63 const auto *Compare = Result.Nodes.getNodeAs<Stmt>("compare");
64
65 auto Diag = diag(Matched->getBeginLoc(), CompareMessage);
66
67 if (Str1->isArrow())
68 Diag << FixItHint::CreateInsertion(Str1->getBeginLoc(), "*");
69
70 Diag << tooling::fixit::createReplacement(*Zero, *Str2, Ctx)
71 << tooling::fixit::createReplacement(*Compare, *Str1->getBase(),
72 Ctx);
73 }
74 }
75
76 // FIXME: Add fixit to fix the code for case one and two (match1).
77 }
78
79 } // namespace readability
80 } // namespace tidy
81 } // namespace clang
clang::ast_matchers
Definition: AbseilMatcher.h:14
Ctx
Context Ctx
Definition: TUScheduler.cpp:237
StringCompareCheck.h
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::tidy::readability::CompareMessage
static const StringRef CompareMessage
Definition: StringCompareCheck.cpp:21