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mptremptre
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Fix #12989: Honor attribute cleanup in unusedFunction (cppcheck-opensource#6656)
Gets rid of FPs when a static function is only used with attribute cleanup.
1 parent b62cb22 commit 7ece4f6

4 files changed

Lines changed: 57 additions & 16 deletions

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‎lib/checkunusedfunctions.cpp‎

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -221,6 +221,13 @@ void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer, const Setting
221221
}
222222
}
223223

224+
if (tok->hasAttributeCleanup()) {
225+
const std::string& funcname = tok->getAttributeCleanup();
226+
mFunctions[funcname].usedOtherFile = true;
227+
mFunctionCalls.insert(funcname);
228+
continue;
229+
}
230+
224231
const Token *funcname = nullptr;
225232

226233
if (doMarkup)

‎lib/token.h‎

Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -133,6 +133,8 @@ struct TokenImpl {
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mAttributeAlignas->push_back(a);
134134
}
135135

136+
std::string mAttributeCleanup;
137+
136138
// For memoization, to speed up parsing of huge arrays #8897
137139
enum class Cpp11init : std::uint8_t { UNKNOWN, CPP11INIT, NOINIT } mCpp11init = Cpp11init::UNKNOWN;
138140

@@ -565,6 +567,15 @@ class CPPCHECKLIB Token {
565567
void addAttributeAlignas(const std::string& a) {
566568
mImpl->addAttributeAlignas(a);
567569
}
570+
void addAttributeCleanup(const std::string& funcname) {
571+
mImpl->mAttributeCleanup = funcname;
572+
}
573+
const std::string& getAttributeCleanup() const {
574+
return mImpl->mAttributeCleanup;
575+
}
576+
bool hasAttributeCleanup() const {
577+
return !mImpl->mAttributeCleanup.empty();
578+
}
568579
void setCppcheckAttribute(TokenImpl::CppcheckAttributes::Type type, MathLib::bigint value) {
569580
mImpl->setCppcheckAttribute(type, value);
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}

‎lib/tokenize.cpp‎

Lines changed: 29 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -9146,6 +9146,26 @@ static Token* getTokenAfterAttributes(Token* tok, bool gccattr) {
91469146
return after;
91479147
}
91489148

9149+
static Token* getVariableTokenAfterAttributes(Token* tok) {
9150+
Token *vartok = nullptr;
9151+
Token *after = getTokenAfterAttributes(tok, true);
9152+
9153+
// check if after variable name
9154+
if (Token::Match(after, ";|=")) {
9155+
Token *prev = tok->previous();
9156+
while (Token::simpleMatch(prev, "]"))
9157+
prev = prev->link()->previous();
9158+
if (Token::Match(prev, "%type%"))
9159+
vartok = prev;
9160+
}
9161+
9162+
// check if before variable name
9163+
else if (Token::Match(after, "%type%"))
9164+
vartok = after;
9165+
9166+
return vartok;
9167+
}
9168+
91499169
Token* Tokenizer::getAttributeFuncTok(Token* tok, bool gccattr) const {
91509170
if (!Token::Match(tok, "%name% ("))
91519171
return nullptr;
@@ -9237,22 +9257,7 @@ void Tokenizer::simplifyAttribute()
92379257
}
92389258

92399259
else if (Token::Match(attr, "[(,] unused|__unused__|used|__used__ [,)]")) {
9240-
Token *vartok = nullptr;
9241-
Token *after = getTokenAfterAttributes(tok, true);
9242-
9243-
// check if after variable name
9244-
if (Token::Match(after, ";|=")) {
9245-
Token *prev = tok->previous();
9246-
while (Token::simpleMatch(prev, "]"))
9247-
prev = prev->link()->previous();
9248-
if (Token::Match(prev, "%type%"))
9249-
vartok = prev;
9250-
}
9251-
9252-
// check if before variable name
9253-
else if (Token::Match(after, "%type%"))
9254-
vartok = after;
9255-
9260+
Token *vartok = getVariableTokenAfterAttributes(tok);
92569261
if (vartok) {
92579262
const std::string &attribute(attr->strAt(1));
92589263
if (attribute.find("unused") != std::string::npos)
@@ -9284,6 +9289,14 @@ void Tokenizer::simplifyAttribute()
92849289

92859290
else if (functok && Token::simpleMatch(attr, "( __visibility__ ( \"default\" ) )"))
92869291
functok->isAttributeExport(true);
9292+
9293+
else if (Token::Match(attr, "[(,] cleanup ( %name% )")) {
9294+
Token *vartok = getVariableTokenAfterAttributes(tok);
9295+
if (vartok) {
9296+
const std::string& funcname = attr->strAt(3);
9297+
vartok->addAttributeCleanup(funcname);
9298+
}
9299+
}
92879300
}
92889301

92899302
Token::eraseTokens(tok, tok->linkAt(1)->next());

‎test/testunusedfunctions.cpp‎

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -85,6 +85,7 @@ class TestUnusedFunctions : public TestFixture {
8585
TEST_CASE(virtualFunc);
8686
TEST_CASE(parensInit);
8787
TEST_CASE(typeInCast);
88+
TEST_CASE(attributeCleanup);
8889
}
8990

9091
#define check(...) check_(__FILE__, __LINE__, __VA_ARGS__)
@@ -769,6 +770,15 @@ class TestUnusedFunctions : public TestFixture {
769770
"}\n");
770771
ASSERT_EQUALS("[test.cpp:2]: (style) The function 'Type' is never used.\n", errout_str());
771772
}
773+
774+
void attributeCleanup()
775+
{
776+
check("void clean(void *ptr) {}\n"
777+
"int main() {\n"
778+
" void * __attribute__((cleanup(clean))) p;\n"
779+
"}\n");
780+
ASSERT_EQUALS("", errout_str());
781+
}
772782
};
773783

774784
REGISTER_TEST(TestUnusedFunctions)

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