llvm-project/clang-tools-extra/clang-tidy/performance/FasterStringFindCheck.cpp

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4.1 KiB
C++

//===--- FasterStringFindCheck.cpp - clang-tidy----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "FasterStringFindCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "llvm/ADT/Optional.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace performance {
namespace {
static const char StringLikeClassesDelimiter[] = ";";
std::vector<std::string> ParseClasses(StringRef Option) {
SmallVector<StringRef, 4> Classes;
Option.split(Classes, StringLikeClassesDelimiter);
std::vector<std::string> Result;
for (StringRef &Class : Classes) {
Class = Class.trim();
if (!Class.empty())
Result.push_back(Class);
}
return Result;
}
llvm::Optional<std::string> MakeCharacterLiteral(const StringLiteral *Literal) {
std::string Result;
{
llvm::raw_string_ostream OS(Result);
Literal->outputString(OS);
}
// Now replace the " with '.
auto pos = Result.find_first_of('"');
if (pos == Result.npos) return llvm::None;
Result[pos] = '\'';
pos = Result.find_last_of('"');
if (pos == Result.npos) return llvm::None;
Result[pos] = '\'';
return Result;
}
AST_MATCHER(StringLiteral, lengthIsOne) { return Node.getLength() == 1; }
AST_MATCHER_FUNCTION(ast_matchers::internal::Matcher<Expr>,
hasSubstitutedType) {
return hasType(qualType(anyOf(substTemplateTypeParmType(),
hasDescendant(substTemplateTypeParmType()))));
}
} // namespace
FasterStringFindCheck::FasterStringFindCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
StringLikeClasses(
ParseClasses(Options.get("StringLikeClasses", "std::basic_string"))) {
}
void FasterStringFindCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "StringLikeClasses",
llvm::join(StringLikeClasses.begin(), StringLikeClasses.end(),
StringLikeClassesDelimiter));
}
void FasterStringFindCheck::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus)
return;
const auto SingleChar =
expr(ignoringParenCasts(stringLiteral(lengthIsOne()).bind("literal")));
const auto StringFindFunctions =
anyOf(hasName("find"), hasName("rfind"), hasName("find_first_of"),
hasName("find_first_not_of"), hasName("find_last_of"),
hasName("find_last_not_of"));
llvm::Optional<ast_matchers::internal::Matcher<NamedDecl>> IsStringClass;
for (const auto &ClassName : StringLikeClasses) {
const auto HasName = hasName(ClassName);
IsStringClass = IsStringClass ? anyOf(*IsStringClass, HasName) : HasName;
}
if (IsStringClass) {
Finder->addMatcher(
cxxMemberCallExpr(
callee(functionDecl(StringFindFunctions).bind("func")),
anyOf(argumentCountIs(1), argumentCountIs(2)),
hasArgument(0, SingleChar),
on(expr(hasType(recordDecl(*IsStringClass)),
unless(hasSubstitutedType())))),
this);
}
}
void FasterStringFindCheck::check(const MatchFinder::MatchResult &Result) {
const auto *Literal = Result.Nodes.getNodeAs<StringLiteral>("literal");
const auto *FindFunc = Result.Nodes.getNodeAs<FunctionDecl>("func");
auto Replacement = MakeCharacterLiteral(Literal);
if (!Replacement)
return;
diag(Literal->getLocStart(), "%0 called with a string literal consisting of "
"a single character; consider using the more "
"effective overload accepting a character")
<< FindFunc->getName()
<< FixItHint::CreateReplacement(
CharSourceRange::getTokenRange(Literal->getLocStart(),
Literal->getLocEnd()),
*Replacement);
}
} // namespace performance
} // namespace tidy
} // namespace clang