clang-tools 18.0.0git
UnusedReturnValueCheck.cpp
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1//===--- UnusedReturnValueCheck.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
10#include "../utils/Matchers.h"
11#include "../utils/OptionsUtils.h"
12#include "clang/AST/ASTContext.h"
13#include "clang/ASTMatchers/ASTMatchFinder.h"
14
15using namespace clang::ast_matchers;
16using namespace clang::ast_matchers::internal;
17
18namespace clang::tidy::bugprone {
19
20namespace {
21
22// Matches functions that are instantiated from a class template member function
23// matching InnerMatcher. Functions not instantiated from a class template
24// member function are matched directly with InnerMatcher.
25AST_MATCHER_P(FunctionDecl, isInstantiatedFrom, Matcher<FunctionDecl>,
26 InnerMatcher) {
27 FunctionDecl *InstantiatedFrom = Node.getInstantiatedFromMemberFunction();
28 return InnerMatcher.matches(InstantiatedFrom ? *InstantiatedFrom : Node,
29 Finder, Builder);
30}
31} // namespace
32
34 ClangTidyContext *Context)
35 : ClangTidyCheck(Name, Context),
36 CheckedFunctions(Options.get("CheckedFunctions",
37 "::std::async;"
38 "::std::launder;"
39 "::std::remove;"
40 "::std::remove_if;"
41 "::std::unique;"
42 "::std::unique_ptr::release;"
43 "::std::basic_string::empty;"
44 "::std::vector::empty;"
45 "::std::back_inserter;"
46 "::std::distance;"
47 "::std::find;"
48 "::std::find_if;"
49 "::std::inserter;"
50 "::std::lower_bound;"
51 "::std::make_pair;"
52 "::std::map::count;"
53 "::std::map::find;"
54 "::std::map::lower_bound;"
55 "::std::multimap::equal_range;"
56 "::std::multimap::upper_bound;"
57 "::std::set::count;"
58 "::std::set::find;"
59 "::std::setfill;"
60 "::std::setprecision;"
61 "::std::setw;"
62 "::std::upper_bound;"
63 "::std::vector::at;"
64 // C standard library
65 "::bsearch;"
66 "::ferror;"
67 "::feof;"
68 "::isalnum;"
69 "::isalpha;"
70 "::isblank;"
71 "::iscntrl;"
72 "::isdigit;"
73 "::isgraph;"
74 "::islower;"
75 "::isprint;"
76 "::ispunct;"
77 "::isspace;"
78 "::isupper;"
79 "::iswalnum;"
80 "::iswprint;"
81 "::iswspace;"
82 "::isxdigit;"
83 "::memchr;"
84 "::memcmp;"
85 "::strcmp;"
86 "::strcoll;"
87 "::strncmp;"
88 "::strpbrk;"
89 "::strrchr;"
90 "::strspn;"
91 "::strstr;"
92 "::wcscmp;"
93 // POSIX
94 "::access;"
95 "::bind;"
96 "::connect;"
97 "::difftime;"
98 "::dlsym;"
99 "::fnmatch;"
100 "::getaddrinfo;"
101 "::getopt;"
102 "::htonl;"
103 "::htons;"
104 "::iconv_open;"
105 "::inet_addr;"
106 "::isascii;"
107 "::isatty;"
108 "::mmap;"
109 "::newlocale;"
110 "::openat;"
111 "::pathconf;"
112 "::pthread_equal;"
113 "::pthread_getspecific;"
114 "::pthread_mutex_trylock;"
115 "::readdir;"
116 "::readlink;"
117 "::recvmsg;"
118 "::regexec;"
119 "::scandir;"
120 "::semget;"
121 "::setjmp;"
122 "::shm_open;"
123 "::shmget;"
124 "::sigismember;"
125 "::strcasecmp;"
126 "::strsignal;"
127 "::ttyname")),
128 CheckedReturnTypes(utils::options::parseStringList(
129 Options.get("CheckedReturnTypes", "::std::error_code;"
130 "::std::error_condition;"
131 "::std::errc;"
132 "::std::expected;"
133 "::boost::system::error_code"))) {}
134
136 Options.store(Opts, "CheckedFunctions", CheckedFunctions);
137 Options.store(Opts, "CheckedReturnTypes",
138 utils::options::serializeStringList(CheckedReturnTypes));
139}
140
142 auto FunVec = utils::options::parseStringList(CheckedFunctions);
143
144 auto MatchedCallExpr = expr(ignoringImplicit(ignoringParenImpCasts(
145 callExpr(callee(functionDecl(
146 // Don't match void overloads of checked functions.
147 unless(returns(voidType())),
148 anyOf(isInstantiatedFrom(hasAnyName(FunVec)),
149 returns(hasCanonicalType(hasDeclaration(
151 CheckedReturnTypes)))))))))
152 .bind("match"))));
153
154 auto UnusedInCompoundStmt =
155 compoundStmt(forEach(MatchedCallExpr),
156 // The checker can't currently differentiate between the
157 // return statement and other statements inside GNU statement
158 // expressions, so disable the checker inside them to avoid
159 // false positives.
160 unless(hasParent(stmtExpr())));
161 auto UnusedInIfStmt =
162 ifStmt(eachOf(hasThen(MatchedCallExpr), hasElse(MatchedCallExpr)));
163 auto UnusedInWhileStmt = whileStmt(hasBody(MatchedCallExpr));
164 auto UnusedInDoStmt = doStmt(hasBody(MatchedCallExpr));
165 auto UnusedInForStmt =
166 forStmt(eachOf(hasLoopInit(MatchedCallExpr),
167 hasIncrement(MatchedCallExpr), hasBody(MatchedCallExpr)));
168 auto UnusedInRangeForStmt = cxxForRangeStmt(hasBody(MatchedCallExpr));
169 auto UnusedInCaseStmt = switchCase(forEach(MatchedCallExpr));
170
171 Finder->addMatcher(
172 stmt(anyOf(UnusedInCompoundStmt, UnusedInIfStmt, UnusedInWhileStmt,
173 UnusedInDoStmt, UnusedInForStmt, UnusedInRangeForStmt,
174 UnusedInCaseStmt)),
175 this);
176}
177
178void UnusedReturnValueCheck::check(const MatchFinder::MatchResult &Result) {
179 if (const auto *Matched = Result.Nodes.getNodeAs<CallExpr>("match")) {
180 diag(Matched->getBeginLoc(),
181 "the value returned by this function should be used")
182 << Matched->getSourceRange();
183 diag(Matched->getBeginLoc(),
184 "cast the expression to void to silence this warning",
185 DiagnosticIDs::Note);
186 }
187}
188
189} // namespace clang::tidy::bugprone
CodeCompletionBuilder Builder
llvm::StringRef Name
::clang::DynTypedNode Node
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.
Base class for all clang-tidy checks.
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
UnusedReturnValueCheck(StringRef Name, ClangTidyContext *Context)
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
AST_MATCHER_P(FunctionDecl, parameterCountGE, unsigned, N)
Matches functions that have at least the specified amount of parameters.
inline ::clang::ast_matchers::internal::Matcher< NamedDecl > matchesAnyListedName(llvm::ArrayRef< StringRef > NameList)
std::string serializeStringList(ArrayRef< StringRef > Strings)
Serialize a sequence of names that can be parsed by parseStringList.
std::vector< StringRef > parseStringList(StringRef Option)
Parse a semicolon separated list of strings.
llvm::StringMap< ClangTidyValue > OptionMap