1 //===--- FasterStringFindCheck.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 "FasterStringFindCheck.h"
10 #include "../utils/OptionsUtils.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "llvm/ADT/Optional.h"
14 #include "llvm/Support/raw_ostream.h"
15
16 using namespace clang::ast_matchers;
17
18 namespace clang {
19 namespace tidy {
20 namespace performance {
21
22 namespace {
23
MakeCharacterLiteral(const StringLiteral * Literal)24 llvm::Optional<std::string> MakeCharacterLiteral(const StringLiteral *Literal) {
25 std::string Result;
26 {
27 llvm::raw_string_ostream OS(Result);
28 Literal->outputString(OS);
29 }
30 // Now replace the " with '.
31 auto pos = Result.find_first_of('"');
32 if (pos == Result.npos)
33 return llvm::None;
34 Result[pos] = '\'';
35 pos = Result.find_last_of('"');
36 if (pos == Result.npos)
37 return llvm::None;
38 Result[pos] = '\'';
39 return Result;
40 }
41
AST_MATCHER_FUNCTION(ast_matchers::internal::Matcher<Expr>,hasSubstitutedType)42 AST_MATCHER_FUNCTION(ast_matchers::internal::Matcher<Expr>,
43 hasSubstitutedType) {
44 return hasType(qualType(anyOf(substTemplateTypeParmType(),
45 hasDescendant(substTemplateTypeParmType()))));
46 }
47
48 } // namespace
49
FasterStringFindCheck(StringRef Name,ClangTidyContext * Context)50 FasterStringFindCheck::FasterStringFindCheck(StringRef Name,
51 ClangTidyContext *Context)
52 : ClangTidyCheck(Name, Context),
53 StringLikeClasses(utils::options::parseStringList(
54 Options.get("StringLikeClasses",
55 "::std::basic_string;::std::basic_string_view"))) {}
56
storeOptions(ClangTidyOptions::OptionMap & Opts)57 void FasterStringFindCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
58 Options.store(Opts, "StringLikeClasses",
59 utils::options::serializeStringList(StringLikeClasses));
60 }
61
registerMatchers(MatchFinder * Finder)62 void FasterStringFindCheck::registerMatchers(MatchFinder *Finder) {
63 const auto SingleChar =
64 expr(ignoringParenCasts(stringLiteral(hasSize(1)).bind("literal")));
65 const auto StringFindFunctions =
66 hasAnyName("find", "rfind", "find_first_of", "find_first_not_of",
67 "find_last_of", "find_last_not_of");
68
69 Finder->addMatcher(
70 cxxMemberCallExpr(
71 callee(functionDecl(StringFindFunctions).bind("func")),
72 anyOf(argumentCountIs(1), argumentCountIs(2)),
73 hasArgument(0, SingleChar),
74 on(expr(
75 hasType(hasUnqualifiedDesugaredType(recordType(hasDeclaration(
76 recordDecl(hasAnyName(SmallVector<StringRef, 4>(
77 StringLikeClasses.begin(), StringLikeClasses.end()))))))),
78 unless(hasSubstitutedType())))),
79 this);
80 }
81
check(const MatchFinder::MatchResult & Result)82 void FasterStringFindCheck::check(const MatchFinder::MatchResult &Result) {
83 const auto *Literal = Result.Nodes.getNodeAs<StringLiteral>("literal");
84 const auto *FindFunc = Result.Nodes.getNodeAs<FunctionDecl>("func");
85
86 auto Replacement = MakeCharacterLiteral(Literal);
87 if (!Replacement)
88 return;
89
90 diag(Literal->getBeginLoc(), "%0 called with a string literal consisting of "
91 "a single character; consider using the more "
92 "effective overload accepting a character")
93 << FindFunc
94 << FixItHint::CreateReplacement(
95 CharSourceRange::getTokenRange(Literal->getBeginLoc(),
96 Literal->getEndLoc()),
97 *Replacement);
98 }
99
100 } // namespace performance
101 } // namespace tidy
102 } // namespace clang
103