clang-tools  4.0.0
FasterStringFindCheck.cpp
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1 //===--- FasterStringFindCheck.cpp - clang-tidy----------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "FasterStringFindCheck.h"
11 #include "../utils/OptionsUtils.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/ASTMatchers/ASTMatchFinder.h"
14 #include "llvm/ADT/Optional.h"
15 #include "llvm/Support/raw_ostream.h"
16 
17 using namespace clang::ast_matchers;
18 
19 namespace clang {
20 namespace tidy {
21 namespace performance {
22 
23 namespace {
24 
25 llvm::Optional<std::string> MakeCharacterLiteral(const StringLiteral *Literal) {
26  std::string Result;
27  {
28  llvm::raw_string_ostream OS(Result);
29  Literal->outputString(OS);
30  }
31  // Now replace the " with '.
32  auto pos = Result.find_first_of('"');
33  if (pos == Result.npos)
34  return llvm::None;
35  Result[pos] = '\'';
36  pos = Result.find_last_of('"');
37  if (pos == Result.npos)
38  return llvm::None;
39  Result[pos] = '\'';
40  return Result;
41 }
42 
43 AST_MATCHER_FUNCTION(ast_matchers::internal::Matcher<Expr>,
44  hasSubstitutedType) {
45  return hasType(qualType(anyOf(substTemplateTypeParmType(),
46  hasDescendant(substTemplateTypeParmType()))));
47 }
48 
49 } // namespace
50 
51 FasterStringFindCheck::FasterStringFindCheck(StringRef Name,
53  : ClangTidyCheck(Name, Context),
54  StringLikeClasses(utils::options::parseStringList(
55  Options.get("StringLikeClasses", "std::basic_string"))) {}
56 
58  Options.store(Opts, "StringLikeClasses",
59  utils::options::serializeStringList(StringLikeClasses));
60 }
61 
63  if (!getLangOpts().CPlusPlus)
64  return;
65 
66  const auto SingleChar =
67  expr(ignoringParenCasts(stringLiteral(hasSize(1)).bind("literal")));
68 
69  const auto StringFindFunctions =
70  anyOf(hasName("find"), hasName("rfind"), hasName("find_first_of"),
71  hasName("find_first_not_of"), hasName("find_last_of"),
72  hasName("find_last_not_of"));
73 
74  llvm::Optional<ast_matchers::internal::Matcher<NamedDecl>> IsStringClass;
75 
76  for (const auto &ClassName : StringLikeClasses) {
77  const auto HasName = hasName(ClassName);
78  IsStringClass = IsStringClass ? anyOf(*IsStringClass, HasName) : HasName;
79  }
80 
81  if (IsStringClass) {
82  Finder->addMatcher(
83  cxxMemberCallExpr(
84  callee(functionDecl(StringFindFunctions).bind("func")),
85  anyOf(argumentCountIs(1), argumentCountIs(2)),
86  hasArgument(0, SingleChar),
87  on(expr(hasType(recordDecl(*IsStringClass)),
88  unless(hasSubstitutedType())))),
89  this);
90  }
91 }
92 
93 void FasterStringFindCheck::check(const MatchFinder::MatchResult &Result) {
94  const auto *Literal = Result.Nodes.getNodeAs<StringLiteral>("literal");
95  const auto *FindFunc = Result.Nodes.getNodeAs<FunctionDecl>("func");
96 
97  auto Replacement = MakeCharacterLiteral(Literal);
98  if (!Replacement)
99  return;
100 
101  diag(Literal->getLocStart(), "%0 called with a string literal consisting of "
102  "a single character; consider using the more "
103  "effective overload accepting a character")
104  << FindFunc << FixItHint::CreateReplacement(
105  CharSourceRange::getTokenRange(Literal->getLocStart(),
106  Literal->getLocEnd()),
107  *Replacement);
108 }
109 
110 } // namespace performance
111 } // namespace tidy
112 } // namespace clang
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
const std::string Name
Definition: USRFinder.cpp:164
LangOptions getLangOpts() const
Returns the language options from the context.
Definition: ClangTidy.h:187
std::string serializeStringList(ArrayRef< std::string > Strings)
Serialize a sequence of names that can be parsed by parseStringList.
std::unique_ptr< ast_matchers::MatchFinder > Finder
Definition: ClangTidy.cpp:262
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Base class for all clang-tidy checks.
Definition: ClangTidy.h:127
std::vector< std::string > parseStringList(StringRef Option)
Parse a semicolon separated list of strings.
AST_MATCHER_FUNCTION(ast_matchers::TypeMatcher, isReferenceToConst)
Definition: Matchers.h:42
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: ClangTidy.cpp:436
std::map< std::string, std::string > OptionMap
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
ClangTidyContext & Context
Definition: ClangTidy.cpp:87
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
Definition: ClangTidy.cpp:403
const NamedDecl * Result
Definition: USRFinder.cpp:162