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Fix #11547 FN stlcstrParam with std::string_view (#5093) 

* Fix #11547 FN stlcstrParam with std::string_view

* Add suppression

* Use emplace()
This commit is contained in:
chrchr-github 2023-05-28 01:11:11 +02:00 committed by GitHub
parent 6b9fac41f4
commit 17789778c9
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GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 33 additions and 15 deletions
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32
lib/checkstl.cpp
View File

@ -1899,15 +1899,19 @@ void CheckStl::string_c_str()
const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
// Find all functions that take std::string as argument
std::multimap<const Function*, int> c_strFuncParam;
struct StrArg {
nonneg int n; // cppcheck-suppress unusedStructMember // FP used through iterator/pair
std::string argtype; // cppcheck-suppress unusedStructMember
};
std::multimap<const Function*, StrArg> c_strFuncParam;
if (printPerformance) {
for (const Scope &scope : symbolDatabase->scopeList) {
for (const Function &func : scope.functionList) {
int numpar = 0;
nonneg int numpar = 0;
for (const Variable &var : func.argumentList) {
numpar++;
if (var.isStlStringType() && (!var.isReference() || var.isConst()))
c_strFuncParam.insert(std::make_pair(&func, numpar));
if ((var.isStlStringType() || var.isStlStringViewType()) && (!var.isReference() || var.isConst()))
c_strFuncParam.emplace(&func, StrArg{ numpar, var.getTypeName() });
}
}
}
@ -1959,20 +1963,20 @@ void CheckStl::string_c_str()
string_c_strAssignment(tok);
}
} else if (printPerformance && tok->function() && Token::Match(tok, "%name% ( !!)") && tok->str() != scope.className) {
const std::pair<std::multimap<const Function*, int>::const_iterator, std::multimap<const Function*, int>::const_iterator> range = c_strFuncParam.equal_range(tok->function());
for (std::multimap<const Function*, int>::const_iterator i = range.first; i != range.second; ++i) {
if (i->second == 0)
const auto range = c_strFuncParam.equal_range(tok->function());
for (std::multimap<const Function*, StrArg>::const_iterator i = range.first; i != range.second; ++i) {
if (i->second.n == 0)
continue;
const Token* tok2 = tok->tokAt(2);
int j;
for (j = 0; tok2 && j < i->second-1; j++)
for (j = 0; tok2 && j < i->second.n - 1; j++)
tok2 = tok2->nextArgument();
if (tok2)
tok2 = tok2->nextArgument();
else
break;
if (!tok2 && j == i->second-1)
if (!tok2 && j == i->second.n - 1)
tok2 = tok->next()->link();
else if (tok2)
tok2 = tok2->previous();
@ -1980,11 +1984,11 @@ void CheckStl::string_c_str()
break;
if (tok2 && Token::Match(tok2->tokAt(-4), ". c_str|data ( )")) {
if (isString(tok2->tokAt(-4)->astOperand1())) {
string_c_strParam(tok, i->second);
string_c_strParam(tok, i->second.n, i->second.argtype);
} else if (Token::Match(tok2->tokAt(-9), "%name% . str ( )")) { // Check ss.str().c_str() as parameter
const Variable* ssVar = tok2->tokAt(-9)->variable();
if (ssVar && ssVar->isStlType(stl_string_stream))
string_c_strParam(tok, i->second);
string_c_strParam(tok, i->second.n, i->second.argtype);
}
}
}
@ -2103,11 +2107,11 @@ void CheckStl::string_c_strReturn(const Token* tok)
"The conversion from const char* as returned by c_str() to std::string creates an unnecessary string copy. Solve that by directly returning the string.", CWE704, Certainty::normal);
}
void CheckStl::string_c_strParam(const Token* tok, nonneg int number)
void CheckStl::string_c_strParam(const Token* tok, nonneg int number, const std::string& argtype)
{
std::ostringstream oss;
oss << "Passing the result of c_str() to a function that takes std::string as argument no. " << number << " is slow and redundant.\n"
"The conversion from const char* as returned by c_str() to std::string creates an unnecessary string copy. Solve that by directly passing the string.";
oss << "Passing the result of c_str() to a function that takes " << argtype << " as argument no. " << number << " is slow and redundant.\n"
"The conversion from const char* as returned by c_str() to " << argtype << " creates an unnecessary string copy or length calculation. Solve that by directly passing the string.";
reportError(tok, Severity::performance, "stlcstrParam", oss.str(), CWE704, Certainty::normal);
}

2
lib/checkstl.h
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@ -192,7 +192,7 @@ private:
void string_c_strThrowError(const Token* tok);
void string_c_strError(const Token* tok);
void string_c_strReturn(const Token* tok);
void string_c_strParam(const Token* tok, nonneg int number);
void string_c_strParam(const Token* tok, nonneg int number, const std::string& argtype = "std::string");
void string_c_strConstructor(const Token* tok);
void string_c_strAssignment(const Token* tok);
void string_c_strConcat(const Token* tok);

5
lib/symboldatabase.cpp
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@ -2335,6 +2335,11 @@ const Type* Variable::iteratorType() const
return nullptr;
}
bool Variable::isStlStringViewType() const
{
return getFlag(fIsStlType) && valueType() && valueType()->container && valueType()->container->stdStringLike && valueType()->container->view;
}
std::string Variable::getTypeName() const
{
std::string ret;

2
lib/symboldatabase.h
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@ -594,6 +594,8 @@ public:
return getFlag(fIsStlString);
}
bool isStlStringViewType() const;
bool isSmartPointer() const {
return getFlag(fIsSmartPointer);
}

7
test/teststl.cpp
View File

@ -4195,6 +4195,13 @@ private:
ASSERT_EQUALS("[test.cpp:6]: (performance) Assigning the result of c_str() to a std::string is slow and redundant.\n"
"[test.cpp:8]: (performance) Assigning the result of c_str() to a std::string is slow and redundant.\n",
errout.str());
check("void f(std::string_view);\n" // #11547
"void g(const std::string & s) {\n"
" f(s.c_str());\n"
"}\n");
ASSERT_EQUALS("[test.cpp:3]: (performance) Passing the result of c_str() to a function that takes std::string_view as argument no. 1 is slow and redundant.\n",
errout.str());
}
void uselessCalls() {