clang-tools  14.0.0git
StringFindStartswithCheck.cpp
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1 //===--- StringFindStartswithCheck.cc - clang-tidy---------------*- C++ -*-===//
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 
10 
11 #include "../utils/OptionsUtils.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/ASTMatchers/ASTMatchers.h"
14 #include "clang/Frontend/CompilerInstance.h"
15 #include "clang/Lex/Lexer.h"
16 #include "clang/Lex/Preprocessor.h"
17 
18 using namespace clang::ast_matchers;
19 
20 namespace clang {
21 namespace tidy {
22 namespace abseil {
23 
24 StringFindStartswithCheck::StringFindStartswithCheck(StringRef Name,
25  ClangTidyContext *Context)
26  : ClangTidyCheck(Name, Context),
27  StringLikeClasses(utils::options::parseStringList(
28  Options.get("StringLikeClasses", "::std::basic_string"))),
29  IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
30  utils::IncludeSorter::IS_LLVM)),
31  AbseilStringsMatchHeader(
32  Options.get("AbseilStringsMatchHeader", "absl/strings/match.h")) {}
33 
35  auto ZeroLiteral = integerLiteral(equals(0));
36  auto StringClassMatcher = cxxRecordDecl(hasAnyName(SmallVector<StringRef, 4>(
37  StringLikeClasses.begin(), StringLikeClasses.end())));
38  auto StringType = hasUnqualifiedDesugaredType(
39  recordType(hasDeclaration(StringClassMatcher)));
40 
41  auto StringFind = cxxMemberCallExpr(
42  // .find()-call on a string...
43  callee(cxxMethodDecl(hasName("find"))),
44  on(hasType(StringType)),
45  // ... with some search expression ...
46  hasArgument(0, expr().bind("needle")),
47  // ... and either "0" as second argument or the default argument (also 0).
48  anyOf(hasArgument(1, ZeroLiteral), hasArgument(1, cxxDefaultArgExpr())));
49 
50  Finder->addMatcher(
51  // Match [=!]= with a zero on one side and a string.find on the other.
52  binaryOperator(
53  hasAnyOperatorName("==", "!="),
54  hasOperands(ignoringParenImpCasts(ZeroLiteral),
55  ignoringParenImpCasts(StringFind.bind("findexpr"))))
56  .bind("expr"),
57  this);
58 }
59 
60 void StringFindStartswithCheck::check(const MatchFinder::MatchResult &Result) {
61  const ASTContext &Context = *Result.Context;
62  const SourceManager &Source = Context.getSourceManager();
63 
64  // Extract matching (sub)expressions
65  const auto *ComparisonExpr = Result.Nodes.getNodeAs<BinaryOperator>("expr");
66  assert(ComparisonExpr != nullptr);
67  const auto *Needle = Result.Nodes.getNodeAs<Expr>("needle");
68  assert(Needle != nullptr);
69  const Expr *Haystack = Result.Nodes.getNodeAs<CXXMemberCallExpr>("findexpr")
70  ->getImplicitObjectArgument();
71  assert(Haystack != nullptr);
72 
73  if (ComparisonExpr->getBeginLoc().isMacroID())
74  return;
75 
76  // Get the source code blocks (as characters) for both the string object
77  // and the search expression
78  const StringRef NeedleExprCode = Lexer::getSourceText(
79  CharSourceRange::getTokenRange(Needle->getSourceRange()), Source,
80  Context.getLangOpts());
81  const StringRef HaystackExprCode = Lexer::getSourceText(
82  CharSourceRange::getTokenRange(Haystack->getSourceRange()), Source,
83  Context.getLangOpts());
84 
85  // Create the StartsWith string, negating if comparison was "!=".
86  bool Neg = ComparisonExpr->getOpcode() == BO_NE;
87 
88  // Create the warning message and a FixIt hint replacing the original expr.
89  auto Diagnostic = diag(ComparisonExpr->getBeginLoc(),
90  "use %select{absl::StartsWith|!absl::StartsWith}0 "
91  "instead of find() %select{==|!=}0 0")
92  << Neg;
93 
94  Diagnostic << FixItHint::CreateReplacement(
95  ComparisonExpr->getSourceRange(),
96  ((Neg ? "!absl::StartsWith(" : "absl::StartsWith(") + HaystackExprCode +
97  ", " + NeedleExprCode + ")")
98  .str());
99 
100  // Create a preprocessor #include FixIt hint (createIncludeInsertion checks
101  // whether this already exists).
102  Diagnostic << IncludeInserter.createIncludeInsertion(
103  Source.getFileID(ComparisonExpr->getBeginLoc()),
104  AbseilStringsMatchHeader);
105 }
106 
108  const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
109  IncludeInserter.registerPreprocessor(PP);
110 }
111 
114  Options.store(Opts, "StringLikeClasses",
115  utils::options::serializeStringList(StringLikeClasses));
116  Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
117  Options.store(Opts, "AbseilStringsMatchHeader", AbseilStringsMatchHeader);
118 }
119 
120 } // namespace abseil
121 } // namespace tidy
122 } // namespace clang
clang::tidy::abseil::StringFindStartswithCheck::check
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Definition: StringFindStartswithCheck.cpp:60
clang::tidy::ClangTidyOptions::OptionMap
llvm::StringMap< ClangTidyValue > OptionMap
Definition: ClangTidyOptions.h:115
clang::tidy::abseil::StringFindStartswithCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: StringFindStartswithCheck.cpp:34
StringFindStartswithCheck.h
clang::tidy::cppcoreguidelines::getSourceText
static std::string getSourceText(const CXXDestructorDecl &Destructor)
Definition: VirtualClassDestructorCheck.cpp:109
clang::tidy::utils::IncludeInserter::registerPreprocessor
void registerPreprocessor(Preprocessor *PP)
Registers this with the Preprocessor PP, must be called before this class is used.
Definition: IncludeInserter.cpp:42
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidyCheck.h:54
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::utils::options::serializeStringList
std::string serializeStringList(ArrayRef< std::string > Strings)
Serialize a sequence of names that can be parsed by parseStringList.
Definition: OptionsUtils.cpp:30
Diagnostic
DiagnosticCallback Diagnostic
Definition: ConfigCompile.cpp:101
clang::tidy::abseil::StringFindStartswithCheck::registerPPCallbacks
void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) override
Override this to register PPCallbacks in the preprocessor.
Definition: StringFindStartswithCheck.cpp:107
clang::tidy::utils::options::parseStringList
std::vector< std::string > parseStringList(StringRef Option)
Parse a semicolon separated list of strings.
Definition: OptionsUtils.cpp:18
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidyCheck.h:416
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:71
Name
static constexpr llvm::StringLiteral Name
Definition: UppercaseLiteralSuffixCheck.cpp:28
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
Definition: ClangTidyCheck.cpp:25
clang::tidy::bugprone::PP
static Preprocessor * PP
Definition: BadSignalToKillThreadCheck.cpp:29
clang::tidy::utils::IncludeInserter::getStyle
IncludeSorter::IncludeStyle getStyle() const
Definition: IncludeInserter.h:84
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::tidy::utils::IncludeInserter::createIncludeInsertion
llvm::Optional< FixItHint > createIncludeInsertion(FileID FileID, llvm::StringRef Header)
Creates a Header inclusion directive fixit in the File FileID.
Definition: IncludeInserter.cpp:70
clang::tidy::abseil::StringFindStartswithCheck::storeOptions
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
Definition: StringFindStartswithCheck.cpp:112
SM
const SourceManager & SM
Definition: IncludeCleaner.cpp:140
clang::tidy::ClangTidyCheck::OptionsView::store
void store(ClangTidyOptions::OptionMap &Options, StringRef LocalName, StringRef Value) const
Stores an option with the check-local name LocalName with string value Value to Options.
Definition: ClangTidyCheck.cpp:120