UnusedReturnValueCheck.cpp
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//===--- UnusedReturnValueCheck.cpp - clang-tidy---------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "UnusedReturnValueCheck.h"
#include "../utils/OptionsUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
using namespace clang::ast_matchers;
using namespace clang::ast_matchers::internal;
namespace clang {
namespace tidy {
namespace bugprone {
namespace {
// Matches functions that are instantiated from a class template member function
// matching InnerMatcher. Functions not instantiated from a class template
// member function are matched directly with InnerMatcher.
AST_MATCHER_P(FunctionDecl, isInstantiatedFrom, Matcher<FunctionDecl>,
InnerMatcher) {
FunctionDecl *InstantiatedFrom = Node.getInstantiatedFromMemberFunction();
return InnerMatcher.matches(InstantiatedFrom ? *InstantiatedFrom : Node,
Finder, Builder);
}
} // namespace
UnusedReturnValueCheck::UnusedReturnValueCheck(llvm::StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
CheckedFunctions(Options.get("CheckedFunctions",
"::std::async;"
"::std::launder;"
"::std::remove;"
"::std::remove_if;"
"::std::unique;"
"::std::unique_ptr::release;"
"::std::basic_string::empty;"
"::std::vector::empty;"
"::std::back_inserter;"
"::std::distance;"
"::std::find;"
"::std::find_if;"
"::std::inserter;"
"::std::lower_bound;"
"::std::make_pair;"
"::std::map::count;"
"::std::map::find;"
"::std::map::lower_bound;"
"::std::multimap::equal_range;"
"::std::multimap::upper_bound;"
"::std::set::count;"
"::std::set::find;"
"::std::setfill;"
"::std::setprecision;"
"::std::setw;"
"::std::upper_bound;"
"::std::vector::at;"
// C standard library
"::bsearch;"
"::ferror;"
"::feof;"
"::isalnum;"
"::isalpha;"
"::isblank;"
"::iscntrl;"
"::isdigit;"
"::isgraph;"
"::islower;"
"::isprint;"
"::ispunct;"
"::isspace;"
"::isupper;"
"::iswalnum;"
"::iswprint;"
"::iswspace;"
"::isxdigit;"
"::memchr;"
"::memcmp;"
"::strcmp;"
"::strcoll;"
"::strncmp;"
"::strpbrk;"
"::strrchr;"
"::strspn;"
"::strstr;"
"::wcscmp;"
// POSIX
"::access;"
"::bind;"
"::connect;"
"::difftime;"
"::dlsym;"
"::fnmatch;"
"::getaddrinfo;"
"::getopt;"
"::htonl;"
"::htons;"
"::iconv_open;"
"::inet_addr;"
"::isascii;"
"::isatty;"
"::mmap;"
"::newlocale;"
"::openat;"
"::pathconf;"
"::pthread_equal;"
"::pthread_getspecific;"
"::pthread_mutex_trylock;"
"::readdir;"
"::readlink;"
"::recvmsg;"
"::regexec;"
"::scandir;"
"::semget;"
"::setjmp;"
"::shm_open;"
"::shmget;"
"::sigismember;"
"::strcasecmp;"
"::strsignal;"
"::ttyname")) {}
void UnusedReturnValueCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "CheckedFunctions", CheckedFunctions);
}
void UnusedReturnValueCheck::registerMatchers(MatchFinder *Finder) {
auto FunVec = utils::options::parseStringList(CheckedFunctions);
auto MatchedCallExpr = expr(ignoringImplicit(ignoringParenImpCasts(
callExpr(callee(functionDecl(
// Don't match void overloads of checked functions.
unless(returns(voidType())),
isInstantiatedFrom(hasAnyName(
std::vector<StringRef>(FunVec.begin(), FunVec.end()))))))
.bind("match"))));
auto UnusedInCompoundStmt =
compoundStmt(forEach(MatchedCallExpr),
// The checker can't currently differentiate between the
// return statement and other statements inside GNU statement
// expressions, so disable the checker inside them to avoid
// false positives.
unless(hasParent(stmtExpr())));
auto UnusedInIfStmt =
ifStmt(eachOf(hasThen(MatchedCallExpr), hasElse(MatchedCallExpr)));
auto UnusedInWhileStmt = whileStmt(hasBody(MatchedCallExpr));
auto UnusedInDoStmt = doStmt(hasBody(MatchedCallExpr));
auto UnusedInForStmt =
forStmt(eachOf(hasLoopInit(MatchedCallExpr),
hasIncrement(MatchedCallExpr), hasBody(MatchedCallExpr)));
auto UnusedInRangeForStmt = cxxForRangeStmt(hasBody(MatchedCallExpr));
auto UnusedInCaseStmt = switchCase(forEach(MatchedCallExpr));
Finder->addMatcher(
stmt(anyOf(UnusedInCompoundStmt, UnusedInIfStmt, UnusedInWhileStmt,
UnusedInDoStmt, UnusedInForStmt, UnusedInRangeForStmt,
UnusedInCaseStmt)),
this);
}
void UnusedReturnValueCheck::check(const MatchFinder::MatchResult &Result) {
if (const auto *Matched = Result.Nodes.getNodeAs<CallExpr>("match")) {
diag(Matched->getBeginLoc(),
"the value returned by this function should be used")
<< Matched->getSourceRange();
diag(Matched->getBeginLoc(),
"cast the expression to void to silence this warning",
DiagnosticIDs::Note);
}
}
} // namespace bugprone
} // namespace tidy
} // namespace clang