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/Support/raw_ostream.h"
14 #include <optional>
15
16 using namespace clang::ast_matchers;
17
18 namespace clang::tidy::performance {
19
20 namespace {
21
makeCharacterLiteral(const StringLiteral * Literal)22 std::optional<std::string> makeCharacterLiteral(const StringLiteral *Literal) {
23 std::string Result;
24 {
25 llvm::raw_string_ostream OS(Result);
26 Literal->outputString(OS);
27 }
28 // Now replace the " with '.
29 auto OpenPos = Result.find_first_of('"');
30 if (OpenPos == std::string::npos)
31 return std::nullopt;
32 Result[OpenPos] = '\'';
33
34 auto ClosePos = Result.find_last_of('"');
35 if (ClosePos == std::string::npos)
36 return std::nullopt;
37 Result[ClosePos] = '\'';
38
39 // "'" is OK, but ''' is not, so add a backslash
40 if ((ClosePos - OpenPos) == 2 && Result[OpenPos + 1] == '\'')
41 Result.replace(OpenPos + 1, 1, "\\'");
42
43 return Result;
44 }
45
AST_MATCHER_FUNCTION(ast_matchers::internal::Matcher<Expr>,hasSubstitutedType)46 AST_MATCHER_FUNCTION(ast_matchers::internal::Matcher<Expr>,
47 hasSubstitutedType) {
48 return hasType(qualType(anyOf(substTemplateTypeParmType(),
49 hasDescendant(substTemplateTypeParmType()))));
50 }
51
52 } // namespace
53
FasterStringFindCheck(StringRef Name,ClangTidyContext * Context)54 FasterStringFindCheck::FasterStringFindCheck(StringRef Name,
55 ClangTidyContext *Context)
56 : ClangTidyCheck(Name, Context),
57 StringLikeClasses(utils::options::parseStringList(
58 Options.get("StringLikeClasses",
59 "::std::basic_string;::std::basic_string_view"))) {}
60
storeOptions(ClangTidyOptions::OptionMap & Opts)61 void FasterStringFindCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
62 Options.store(Opts, "StringLikeClasses",
63 utils::options::serializeStringList(StringLikeClasses));
64 }
65
registerMatchers(MatchFinder * Finder)66 void FasterStringFindCheck::registerMatchers(MatchFinder *Finder) {
67 const auto SingleChar =
68 expr(ignoringParenCasts(stringLiteral(hasSize(1)).bind("literal")));
69 const auto StringFindFunctions =
70 hasAnyName("find", "rfind", "find_first_of", "find_first_not_of",
71 "find_last_of", "find_last_not_of");
72
73 Finder->addMatcher(
74 cxxMemberCallExpr(
75 callee(functionDecl(StringFindFunctions).bind("func")),
76 anyOf(argumentCountIs(1), argumentCountIs(2)),
77 hasArgument(0, SingleChar),
78 on(expr(hasType(hasUnqualifiedDesugaredType(recordType(hasDeclaration(
79 recordDecl(hasAnyName(StringLikeClasses)))))),
80 unless(hasSubstitutedType())))),
81 this);
82 }
83
check(const MatchFinder::MatchResult & Result)84 void FasterStringFindCheck::check(const MatchFinder::MatchResult &Result) {
85 const auto *Literal = Result.Nodes.getNodeAs<StringLiteral>("literal");
86 const auto *FindFunc = Result.Nodes.getNodeAs<FunctionDecl>("func");
87
88 auto Replacement = makeCharacterLiteral(Literal);
89 if (!Replacement)
90 return;
91
92 diag(Literal->getBeginLoc(), "%0 called with a string literal consisting of "
93 "a single character; consider using the more "
94 "effective overload accepting a character")
95 << FindFunc
96 << FixItHint::CreateReplacement(
97 CharSourceRange::getTokenRange(Literal->getBeginLoc(),
98 Literal->getEndLoc()),
99 *Replacement);
100 }
101
102 } // namespace clang::tidy::performance
103