clang-tools  14.0.0git
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  const auto StrCompare = cxxMemberCallExpr(
27  callee(cxxMethodDecl(hasName("compare"),
28  ofClass(classTemplateSpecializationDecl(
29  hasName("::std::basic_string"))))),
30  hasArgument(0, expr().bind("str2")), argumentCountIs(1),
31  callee(memberExpr().bind("str1")));
32 
33  // First and second case: cast str.compare(str) to boolean.
34  Finder->addMatcher(
35  traverse(TK_AsIs,
36  implicitCastExpr(hasImplicitDestinationType(booleanType()),
37  has(StrCompare))
38  .bind("match1")),
39  this);
40 
41  // Third and fourth case: str.compare(str) == 0 and str.compare(str) != 0.
42  Finder->addMatcher(
43  binaryOperator(hasAnyOperatorName("==", "!="),
44  hasOperands(StrCompare.bind("compare"),
45  integerLiteral(equals(0)).bind("zero")))
46  .bind("match2"),
47  this);
48 }
49 
50 void StringCompareCheck::check(const MatchFinder::MatchResult &Result) {
51  if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>("match1")) {
52  diag(Matched->getBeginLoc(), CompareMessage);
53  return;
54  }
55 
56  if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>("match2")) {
57  const ASTContext &Ctx = *Result.Context;
58 
59  if (const auto *Zero = Result.Nodes.getNodeAs<Stmt>("zero")) {
60  const auto *Str1 = Result.Nodes.getNodeAs<MemberExpr>("str1");
61  const auto *Str2 = Result.Nodes.getNodeAs<Stmt>("str2");
62  const auto *Compare = Result.Nodes.getNodeAs<Stmt>("compare");
63 
64  auto Diag = diag(Matched->getBeginLoc(), CompareMessage);
65 
66  if (Str1->isArrow())
67  Diag << FixItHint::CreateInsertion(Str1->getBeginLoc(), "*");
68 
69  Diag << tooling::fixit::createReplacement(*Zero, *Str2, Ctx)
70  << tooling::fixit::createReplacement(*Compare, *Str1->getBase(),
71  Ctx);
72  }
73  }
74 
75  // FIXME: Add fixit to fix the code for case one and two (match1).
76 }
77 
78 } // namespace readability
79 } // namespace tidy
80 } // namespace clang
clang::tidy::readability::CompareMessage
static const StringRef CompareMessage
Definition: StringCompareCheck.cpp:21
Ctx
Context Ctx
Definition: TUScheduler.cpp:460
clang::ast_matchers
Definition: AbseilMatcher.h:14
StringCompareCheck.h
clang::clangd::check
bool check(llvm::StringRef File, llvm::function_ref< bool(const Position &)> ShouldCheckLine, const ThreadsafeFS &TFS, const ClangdLSPServer::Options &Opts, bool EnableCodeCompletion)
Definition: Check.cpp:259
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27