clang-tools  9.0.0
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
Context Ctx
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
Definition: Rename.cpp:36
static const StringRef CompareMessage