feat: analyze function side effects (#2901)
This commit is contained in:
miltolstoy
GitHub
parent
1e8eb28390
commit
5d299016f1
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@ -1511,12 +1511,16 @@ bool CheckUnusedVar::isRecordTypeWithoutSideEffects(const Type* type)
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if (initValueVar && !isVariableWithoutSideEffects(*initValueVar)) {
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return withoutSideEffects = false;
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}
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if ((valueToken->tokType() == Token::Type::eFunction) ||
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(valueToken->tokType() == Token::Type::eName) ||
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if ((valueToken->tokType() == Token::Type::eName) ||
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(valueToken->tokType() == Token::Type::eLambda) ||
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(valueToken->tokType() == Token::Type::eOther)) {
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return withoutSideEffects = false;
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}
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const Function* initValueFunc = valueToken->function();
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if (initValueFunc && !isFunctionWithoutSideEffects(*initValueFunc, valueToken,
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std::list<const Function*>{})) {
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return withoutSideEffects = false;
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}
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}
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}
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}
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@ -1586,3 +1590,71 @@ bool CheckUnusedVar::isEmptyType(const Type* type)
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emptyType=false; // unknown types are assumed to be nonempty
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return emptyType;
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}
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bool CheckUnusedVar::isFunctionWithoutSideEffects(const Function& func, const Token* functionUsageToken,
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std::list<const Function*> checkedFuncs) {
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// no body to analyze
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if (!func.hasBody()) {
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return false;
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}
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for (const Token* argsToken = functionUsageToken->next(); !Token::simpleMatch(argsToken, ")"); argsToken = argsToken->next()) {
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const Variable* argVar = argsToken->variable();
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if (argVar && argVar->isGlobal()) {
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return false; // TODO: analyze global variable usage
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}
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}
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bool sideEffectReturnFound = false;
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for (Token* bodyToken = func.functionScope->bodyStart->next(); bodyToken != func.functionScope->bodyEnd;
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bodyToken = bodyToken->next())
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{
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const Variable* bodyVariable = bodyToken->variable();
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if (bodyVariable) {
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// check variable for side-effects
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if (!isVariableWithoutSideEffects(*bodyVariable)) {
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return false;
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}
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// check if global variable is changed
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if (bodyVariable->isGlobal()) {
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return false; // TODO: analyze global variable usage
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}
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}
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// check nested function
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const Function* bodyFunction = bodyToken->function();
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if (bodyFunction) {
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if (std::find(checkedFuncs.begin(), checkedFuncs.end(), bodyFunction) != checkedFuncs.end()) { // recursion found
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continue;
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}
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checkedFuncs.push_back(bodyFunction);
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if (!isFunctionWithoutSideEffects(*bodyFunction, bodyToken, checkedFuncs)) {
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return false;
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}
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}
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// check returned value
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if (Token::simpleMatch(bodyToken, "return")) {
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const Token* returnValueToken = bodyToken->next();
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// TODO: handle complex return expressions
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if (!Token::simpleMatch(returnValueToken->next(), ";")) {
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sideEffectReturnFound = true;
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continue;
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}
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// simple one-token return
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const Variable* returnVariable = returnValueToken->variable();
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if (returnValueToken->isLiteral() ||
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(returnVariable && isVariableWithoutSideEffects(*returnVariable))) {
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continue;
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}
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sideEffectReturnFound = true;
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}
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// unknown name
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if (bodyToken->isNameOnly()) {
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return false;
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}
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}
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return !sideEffectReturnFound;
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}
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@ -35,6 +35,7 @@ class Tokenizer;
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class Type;
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class Variables;
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class Variable;
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class Function;
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/// @addtogroup Checks
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/// @{
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@ -73,6 +74,8 @@ private:
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bool isRecordTypeWithoutSideEffects(const Type* type);
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bool isVariableWithoutSideEffects(const Variable& var);
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bool isEmptyType(const Type* type);
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bool isFunctionWithoutSideEffects(const Function& func, const Token* functionUsageToken,
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std::list<const Function*> checkedFuncs);
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// Error messages..
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void unusedStructMemberError(const Token *tok, const std::string &structname, const std::string &varname, bool isUnion = false);
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@ -433,6 +433,9 @@ public:
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bool isBoolean() const {
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return mTokType == eBoolean;
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}
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bool isIncDecOp() const {
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return mTokType == eIncDecOp;
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}
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bool isBinaryOp() const {
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return astOperand1() != nullptr && astOperand2() != nullptr;
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}
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@ -39,6 +39,7 @@ private:
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LOAD_LIB_2(settings.library, "std.cfg");
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TEST_CASE(isRecordTypeWithoutSideEffects);
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TEST_CASE(cleanFunction);
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TEST_CASE(emptyclass); // #5355 - False positive: Variable is not assigned a value.
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TEST_CASE(emptystruct); // #5355 - False positive: Variable is not assigned a value.
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@ -469,17 +470,6 @@ private:
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"}");
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ASSERT_EQUALS("", errout.str());
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functionVariableUsage(
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"class F {\n"
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"public:\n"
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" F() : x(unknownFunc()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" F f;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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functionVariableUsage(
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"class F {\n"
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"public:\n"
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@ -525,6 +515,509 @@ private:
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ASSERT_EQUALS("", errout.str());
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}
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void cleanFunction()
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{
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// unknown function
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functionVariableUsage(
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"class F {\n"
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"public:\n"
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" F() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" F f;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// function forward declaration
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functionVariableUsage(
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"int func();\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// return literal
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functionVariableUsage(
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"int func() { return 1; }\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("[test.cpp:8]: (style) Unused variable: c\n", errout.str());
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// return variable without side effects
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functionVariableUsage(
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"int func() {\n"
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" int x = 1;\n"
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" return x;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("[test.cpp:11]: (style) Unused variable: c\n", errout.str());
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// return variable with side effects
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functionVariableUsage(
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"int func() {\n"
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" unknown_type x = 1;\n"
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" return x;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// return unknown variable
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functionVariableUsage(
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"int func() {\n"
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" return unknown_var;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// return variable is global, but not changed
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functionVariableUsage(
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"int x = 1;\n"
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"int func() {\n"
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" return x;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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TODO_ASSERT_EQUALS("[test.cpp:11]: (style) Unused variable: c\n", "", errout.str());
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// changing global variable in return
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functionVariableUsage(
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"int x = 1;\n"
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"int func() {\n"
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" return x++;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// changing global variable in function body
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functionVariableUsage(
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"int x = 1;\n"
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"int func() {\n"
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" x++;\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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functionVariableUsage(
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"int x = 1;\n"
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"int func() {\n"
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" --x;\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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functionVariableUsage(
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"int x = 1;\n"
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"int func() {\n"
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" x += 2;\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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functionVariableUsage(
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"int x = 1;\n"
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"int func() {\n"
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" x = 2;\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// changing global array variable in function body
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functionVariableUsage(
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"int x[] = {0, 1, 3};\n"
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"int func() {\n"
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" x[0] = 4;\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// changing local variable
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functionVariableUsage(
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"int func() {\n"
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" int x = 1;\n"
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" x = 2;\n"
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" x++;\n"
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" return x;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("[test.cpp:13]: (style) Unused variable: c\n", errout.str());
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// variable of user-defined class without side effects
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functionVariableUsage(
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"class A {};\n"
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"A func() {\n"
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" A a;\n"
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" return a;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" A x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("[test.cpp:12]: (style) Unused variable: c\n", errout.str());
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// variable of user-defined class with side effects
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functionVariableUsage(
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"class A {\n"
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"public:\n"
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" unknown_type u{1};\n"
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"};\n"
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"int func() {\n"
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" A a;\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// unknown type variable
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functionVariableUsage(
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"int func() {\n"
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" unknown_type a;\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// nested clean function call
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functionVariableUsage(
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"int another_func() { return 1;}\n"
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"int func() {\n"
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" another_func();\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("[test.cpp:12]: (style) Unused variable: c\n", errout.str());
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// nested side-effects function call
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functionVariableUsage(
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"int global = 1;"
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"int another_func() {\n"
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" global++;\n"
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" return global;}\n"
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"int func() {\n"
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" another_func();\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// unknown nested function
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functionVariableUsage(
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"int func() {\n"
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" unknown_func();\n"
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" return 1;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func()) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("", errout.str());
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// clean function recursion
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functionVariableUsage(
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"int func(int i) {\n"
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" if (i != 2) {\n"
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" func(i++);\n"
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" return 2;\n"
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" }\n"
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" return i;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func(0)) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("[test.cpp:14]: (style) Unused variable: c\n", errout.str());
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// indirect clean function recursion
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functionVariableUsage(
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"void another_func() {\n"
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" func(0);\n"
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"}\n"
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"int func(int i) {\n"
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" if (i != 2) {\n"
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" another_func();\n"
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" return 2;\n"
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" }\n"
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" return i;\n"
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"}\n"
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"class C {\n"
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"public:\n"
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" C() : x(func(0)) {}\n"
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" int x;\n"
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"};\n"
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"void f() {\n"
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" C c;\n"
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"}");
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ASSERT_EQUALS("[test.cpp:17]: (style) Unused variable: c\n", errout.str());
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||||
|
||||
// side-effect function recursion
|
||||
functionVariableUsage(
|
||||
"int global = 1;\n"
|
||||
"int func(int i) {\n"
|
||||
" if (i != 2) {\n"
|
||||
" global++;\n"
|
||||
" func(i++);\n"
|
||||
" return 2;\n"
|
||||
" }\n"
|
||||
" return i;\n"
|
||||
"}\n"
|
||||
"class C {\n"
|
||||
"public:\n"
|
||||
" C() : x(func(0)) {}\n"
|
||||
" int x;\n"
|
||||
"};\n"
|
||||
"void f() {\n"
|
||||
" C c;\n"
|
||||
"}");
|
||||
ASSERT_EQUALS("", errout.str());
|
||||
|
||||
// multiple returns (side-effect & clean)
|
||||
functionVariableUsage(
|
||||
"int func(int i) {\n"
|
||||
" if (i == 0) { return 0;}\n"
|
||||
" else { return unknownSideEffectFunction(); }\n"
|
||||
"}\n"
|
||||
"class C {\n"
|
||||
"public:\n"
|
||||
" C() : x(func(0)) {}\n"
|
||||
" int x;\n"
|
||||
"};\n"
|
||||
"void f() {\n"
|
||||
" C c;\n"
|
||||
"}");
|
||||
ASSERT_EQUALS("", errout.str());
|
||||
|
||||
// multiple clean returns
|
||||
functionVariableUsage(
|
||||
"int func(int i) {\n"
|
||||
" if (i == 0) { return 0;}\n"
|
||||
" else { return i; }\n"
|
||||
"}\n"
|
||||
"class C {\n"
|
||||
"public:\n"
|
||||
" C() : x(func(0)) {}\n"
|
||||
" int x;\n"
|
||||
"};\n"
|
||||
"void f() {\n"
|
||||
" C c;\n"
|
||||
"}");
|
||||
ASSERT_EQUALS("[test.cpp:11]: (style) Unused variable: c\n", errout.str());
|
||||
|
||||
// multiple side-effect returns
|
||||
functionVariableUsage(
|
||||
"int func(int i) {\n"
|
||||
" if (i == 0) { return unknownSideEffectFunction();}\n"
|
||||
" else { return unknown_var; }\n"
|
||||
"}\n"
|
||||
"class C {\n"
|
||||
"public:\n"
|
||||
" C() : x(func(0)) {}\n"
|
||||
" int x;\n"
|
||||
"};\n"
|
||||
"void f() {\n"
|
||||
" C c;\n"
|
||||
"}");
|
||||
ASSERT_EQUALS("", errout.str());
|
||||
|
||||
// argument return
|
||||
functionVariableUsage(
|
||||
"int func(int i) {\n"
|
||||
" return i;\n"
|
||||
"}\n"
|
||||
"class C {\n"
|
||||
"public:\n"
|
||||
" C() : x(func(0)) {}\n"
|
||||
" int x;\n"
|
||||
"};\n"
|
||||
"void f() {\n"
|
||||
" C c;\n"
|
||||
"}");
|
||||
ASSERT_EQUALS("[test.cpp:10]: (style) Unused variable: c\n", errout.str());
|
||||
|
||||
// global variable modifying through function argument
|
||||
functionVariableUsage(
|
||||
"char buf[10];\n"
|
||||
"int func(char* p) {\n"
|
||||
" *p = 0;\n"
|
||||
" return 1;\n"
|
||||
"}\n"
|
||||
"class C {\n"
|
||||
"public:\n"
|
||||
" C() : x(func(buf)) {}\n"
|
||||
" int x;\n"
|
||||
"};\n"
|
||||
"void f() {\n"
|
||||
" C c;\n"
|
||||
"}");
|
||||
ASSERT_EQUALS("", errout.str());
|
||||
|
||||
// global variable modifying through local pointer
|
||||
functionVariableUsage(
|
||||
"int global = 1;\n"
|
||||
"int func() {\n"
|
||||
" int *p = &global;\n"
|
||||
" *p = 0;\n"
|
||||
" return 1;\n"
|
||||
"}\n"
|
||||
"class C {\n"
|
||||
"public:\n"
|
||||
" C() : x(func()) {}\n"
|
||||
" int x;\n"
|
||||
"};\n"
|
||||
"void f() {\n"
|
||||
" C c;\n"
|
||||
"}");
|
||||
ASSERT_EQUALS("", errout.str());
|
||||
|
||||
// global struct variable
|
||||
functionVariableUsage(
|
||||
"struct S { int x; } s;\n"
|
||||
"int func() {\n"
|
||||
" s.x = 1;;\n"
|
||||
" return 1;\n"
|
||||
"}\n"
|
||||
"class C {\n"
|
||||
"public:\n"
|
||||
" C() : x(func()) {}\n"
|
||||
" int x;\n"
|
||||
"};\n"
|
||||
"void f() {\n"
|
||||
" C c;\n"
|
||||
"}");
|
||||
ASSERT_EQUALS("", errout.str());
|
||||
}
|
||||
|
||||
// #5355 - False positive: Variable is not assigned a value.
|
||||
void emptyclass() {
|
||||
functionVariableUsage("class Carla {\n"
|
||||
|
|
|
|||
Loading…
Reference in New Issue