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Fix #10704 FN redundantCopyLocalConst (#4115)

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chrchr-github 2022-07-10 11:33:24 +02:00 committed by GitHub
parent c9c1f83a69
commit f5c4a21eae
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8 changed files with 75 additions and 16 deletions
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3
lib/astutils.cpp
View File

@ -2615,7 +2615,8 @@ bool isExpressionChanged(const Token* expr, const Token* start, const Token* end
if (tok->variable()) {
if (tok->variable()->isConst())
return false;
global = !tok->variable()->isLocal() && !tok->variable()->isArgument();
global = !tok->variable()->isLocal() && !tok->variable()->isArgument() &&
!(tok->variable()->isMember() && !tok->variable()->isStatic());
} else if (tok->isIncompleteVar() && !tok->isIncompleteConstant()) {
global = true;
}

29
lib/checkother.cpp
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@ -1181,10 +1181,12 @@ static int estimateSize(const Type* type, const Settings* settings, const Symbol
static bool canBeConst(const Variable *var, const Settings* settings)
{
if (!var->scope())
return false;
{
// check initializer list. If variable is moved from it can't be const.
const Function* func_scope = var->scope()->function;
if (func_scope->type == Function::Type::eConstructor) {
if (func_scope && func_scope->type == Function::Type::eConstructor) {
//could be initialized in initializer list
if (func_scope->arg->link()->next()->str() == ":") {
for (const Token* tok2 = func_scope->arg->link()->next()->next(); tok2 != var->scope()->bodyStart; tok2 = tok2->next()) {
@ -1204,6 +1206,11 @@ static bool canBeConst(const Variable *var, const Settings* settings)
const Token* parent = tok2->astParent();
if (!parent)
continue;
if (Token::simpleMatch(tok2->next(), ";") && tok2->next()->isSplittedVarDeclEq()) {
tok2 = tok2->tokAt(2);
tok2 = Token::findsimplematch(tok2, ";");
continue;
}
if (parent->str() == "<<" || isLikelyStreamRead(true, parent)) {
if (parent->str() == "<<" && parent->astOperand1() == tok2)
return false;
@ -2701,7 +2708,7 @@ void CheckOther::checkRedundantCopy()
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Variable* var : symbolDatabase->variableList()) {
if (!var || var->isReference() || !var->isConst() || var->isPointer() || (!var->type() && !var->isStlType())) // bailout if var is of standard type, if it is a pointer or non-const
if (!var || var->isReference() || (!var->isConst() && !canBeConst(var, mSettings)) || var->isPointer() || (!var->type() && !var->isStlType())) // bailout if var is of standard type, if it is a pointer or non-const
continue;
const Token* startTok = var->nameToken();
@ -2711,6 +2718,8 @@ void CheckOther::checkRedundantCopy()
// Object is instantiated. Warn if constructor takes arguments by value.
if (constructorTakesReference(var->typeScope()))
continue;
} else if (Token::simpleMatch(startTok->next(), ";") && startTok->next()->isSplittedVarDeclEq()) {
startTok = startTok->tokAt(2);
} else
continue;
@ -2723,17 +2732,27 @@ void CheckOther::checkRedundantCopy()
continue;
const Token* dot = tok->astOperand1();
if (Token::simpleMatch(dot, ".") && dot->astOperand1() && isVariableChanged(dot->astOperand1()->variable(), mSettings, mTokenizer->isCPP()))
continue;
if (Token::simpleMatch(dot, ".")) {
if (dot->astOperand1() && isVariableChanged(dot->astOperand1()->variable(), mSettings, mTokenizer->isCPP()))
continue;
if (isTemporary(/*cpp*/ true, dot, &mSettings->library, /*unknown*/ true))
continue;
}
if (exprDependsOnThis(tok->previous()))
continue;
const Function* func = tok->previous()->function();
if (func && func->tokenDef->strAt(-1) == "&") {
redundantCopyError(startTok, startTok->str());
const Scope* fScope = func->functionScope;
if (fScope && fScope->bodyEnd && Token::Match(fScope->bodyEnd->tokAt(-3), "return %var% ;")) {
const Token* varTok = fScope->bodyEnd->tokAt(-2);
if (varTok->variable() && !varTok->variable()->isGlobal())
redundantCopyError(startTok, startTok->str());
}
}
}
}
void CheckOther::redundantCopyError(const Token *tok,const std::string& varname)
{
reportError(tok, Severity::performance, "redundantCopyLocalConst",

4
lib/symboldatabase.cpp
View File

@ -2091,6 +2091,10 @@ Variable& Variable::operator=(const Variable &var)
return *this;
}
bool Variable::isMember() const {
return mScope && mScope->isClassOrStructOrUnion();
}
bool Variable::isPointerArray() const
{
return isArray() && nameToken() && nameToken()->previous() && (nameToken()->previous()->str() == "*");

6
lib/symboldatabase.h
View File

@ -379,6 +379,12 @@ public:
return (mAccess == AccessControl::Local) && !isExtern();
}
/**
* Is variable a member of a user-defined type.
* @return true if member, false if not or unknown
*/
bool isMember() const;
/**
* Is variable mutable.
* @return true if mutable, false if not

1
lib/templatesimplifier.cpp
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@ -3899,7 +3899,6 @@ void TemplateSimplifier::simplifyTemplates(
continue;
}
// cppcheck-suppress redundantCopyLocalConst ; False positive
const std::string strop = op->str();
const std::string strargs = (args && args->isName()) ? args->str() : "";

4
lib/tokenize.cpp
View File

@ -2334,7 +2334,7 @@ bool Tokenizer::simplifyUsing()
Token::Match(tok->linkAt(2), "] ] = ::| %name%")))))
continue;
std::string name = tok->strAt(1);
const std::string& name = tok->strAt(1);
const Token *nameToken = tok->next();
std::string scope = currentScope->fullName;
Token *usingStart = tok;
@ -9518,7 +9518,7 @@ void Tokenizer::simplifyOperatorName()
for (Token *tok = list.front(); tok; tok = tok->next()) {
if (Token::Match(tok, "%op% %str% %name%")) {
std::string name = tok->strAt(2);
const std::string name = tok->strAt(2);
Token * const str = tok->next();
str->deleteNext();
tok->insertToken("operator\"\"" + name);

8
lib/valueflow.cpp
View File

@ -5596,7 +5596,7 @@ static void valueFlowAfterSwap(TokenList* tokenlist,
continue;
for (int i = 0; i < 2; i++) {
std::vector<const Variable*> vars = getVariables(args[0]);
std::list<ValueFlow::Value> values = args[0]->values();
const std::list<ValueFlow::Value>& values = args[0]->values();
valueFlowForwardAssign(args[0], args[1], vars, values, false, tokenlist, errorLogger, settings);
std::swap(args[0], args[1]);
}
@ -6190,7 +6190,7 @@ struct ConditionHandler {
parent = parent->astParent();
bool possible = false;
if (Token::Match(parent, "&&|%oror%")) {
std::string op = parent->str();
const std::string& op(parent->str());
while (parent && parent->str() == op)
parent = parent->astParent();
if (Token::simpleMatch(parent, "!") || Token::simpleMatch(parent, "== false"))
@ -7732,7 +7732,7 @@ static void valueFlowSmartPointer(TokenList *tokenlist, ErrorLogger * errorLogge
if (Token::Match(tok, "%var% (|{") && tok->next()->astOperand2() &&
tok->next()->astOperand2()->str() != ",") {
Token* inTok = tok->next()->astOperand2();
std::list<ValueFlow::Value> values = inTok->values();
const std::list<ValueFlow::Value>& values = inTok->values();
const bool constValue = inTok->isNumber();
valueFlowForwardAssign(inTok, var, values, constValue, true, tokenlist, errorLogger, settings);
@ -7760,7 +7760,7 @@ static void valueFlowSmartPointer(TokenList *tokenlist, ErrorLogger * errorLogge
Token* inTok = ftok->astOperand2();
if (!inTok)
continue;
std::list<ValueFlow::Value> values = inTok->values();
const std::list<ValueFlow::Value>& values = inTok->values();
valueFlowForwardAssign(inTok, tok, vars, values, false, tokenlist, errorLogger, settings);
}
} else if (Token::simpleMatch(tok->astParent(), ". release ( )")) {

36
test/testother.cpp
View File

@ -6657,7 +6657,8 @@ private:
" if (i == j) {}\n"
"}");
ASSERT_EQUALS(
"[test.cpp:4] -> [test.cpp:3]: (style, inconclusive) Same expression used in consecutive assignments of 'i' and 'j'.\n",
"[test.cpp:4] -> [test.cpp:3]: (style, inconclusive) Same expression used in consecutive assignments of 'i' and 'j'.\n"
"[test.cpp:3] -> [test.cpp:4] -> [test.cpp:6]: (style) The comparison 'i == j' is always true because 'i' and 'j' represent the same value.\n",
errout.str());
check("struct A { int x; int y; };"
@ -6669,7 +6670,8 @@ private:
" if (i == a.x) {}\n"
"}");
ASSERT_EQUALS(
"[test.cpp:4] -> [test.cpp:3]: (style, inconclusive) Same expression used in consecutive assignments of 'i' and 'j'.\n",
"[test.cpp:4] -> [test.cpp:3]: (style, inconclusive) Same expression used in consecutive assignments of 'i' and 'j'.\n"
"[test.cpp:3] -> [test.cpp:6]: (style) The comparison 'i == a.x' is always true because 'i' and 'a.x' represent the same value.\n",
errout.str());
check("struct A { int x; int y; };"
@ -6681,7 +6683,8 @@ private:
" if (j == a.x) {}\n"
"}");
ASSERT_EQUALS(
"[test.cpp:4] -> [test.cpp:3]: (style, inconclusive) Same expression used in consecutive assignments of 'i' and 'j'.\n",
"[test.cpp:4] -> [test.cpp:3]: (style, inconclusive) Same expression used in consecutive assignments of 'i' and 'j'.\n"
"[test.cpp:4] -> [test.cpp:6]: (style) The comparison 'j == a.x' is always true because 'j' and 'a.x' represent the same value.\n",
errout.str());
// Issue #8612
@ -7603,6 +7606,33 @@ private:
" }\n"
"};\n", nullptr, /*experimental*/ false, /*inconclusive*/ true);
ASSERT_EQUALS("", errout.str());
// #10704
check("struct C {\n"
" std::string str;\n"
" const std::string& get() const { return str; }\n"
"};\n"
"struct D {\n"
" C c;\n"
" bool f() const {\n"
" std::string s = c.get();\n"
" return s.empty();\n"
" }\n"
"};\n");
ASSERT_EQUALS("[test.cpp:8]: (performance, inconclusive) Use const reference for 's' to avoid unnecessary data copying.\n", errout.str());
check("struct C {\n"
" const std::string & get() const { return m; }\n"
" std::string m;\n"
"};\n"
"C getC();\n"
"void f() {\n"
" const std::string s = getC().get();\n"
"}\n"
"void g() {\n"
" std::string s = getC().get();\n"
"}\n");
ASSERT_EQUALS("", errout.str());
}
void checkNegativeShift() {