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Fix FPs with return conditions (#1455) 

* Fix 8815: FP with identical inner conditions

* Fix issue 8801: FP when not returning a bool

* Fix FP

* Add missing semicolon

* Move returnVar
This commit is contained in:
Paul Fultz II 2018-10-31 03:47:48 -05:00 committed by Daniel Marjamäki
parent ba28cbe0ff
commit fafd0742d4
2 changed files with 40 additions and 20 deletions
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22
lib/checkcondition.cpp
View File

@ -574,16 +574,7 @@ void CheckCondition::multiCondition2()
// Condition..
const Token *cond2 = tok->str() == "if" ? condStartToken->astOperand2() : condStartToken->astOperand1();
// Check if returning boolean values
if (tok->str() == "return") {
const Variable * condVar = nullptr;
if (Token::Match(cond2, "%var% ;"))
condVar = cond2->variable();
else if (Token::Match(cond2, ". %var% ;"))
condVar = cond2->next()->variable();
if (condVar && (condVar->isClass() || condVar->isPointer()))
break;
}
const bool isReturnVar = (tok->str() == "return" && !Token::Match(cond2, "%cop%"));
ErrorPath errorPath;
@ -599,10 +590,10 @@ void CheckCondition::multiCondition2()
tokens1.push(firstCondition->astOperand1());
tokens1.push(firstCondition->astOperand2());
} else if (!firstCondition->hasKnownValue()) {
if (isOppositeCond(false, mTokenizer->isCPP(), firstCondition, cond2, mSettings->library, true, true, &errorPath)) {
if (!isReturnVar && isOppositeCond(false, mTokenizer->isCPP(), firstCondition, cond2, mSettings->library, true, true, &errorPath)) {
if (!isAliased(vars))
oppositeInnerConditionError(firstCondition, cond2, errorPath);
} else if (isSameExpression(mTokenizer->isCPP(), true, firstCondition, cond2, mSettings->library, true, true, &errorPath)) {
} else if (!isReturnVar && isSameExpression(mTokenizer->isCPP(), true, firstCondition, cond2, mSettings->library, true, true, &errorPath)) {
identicalInnerConditionError(firstCondition, cond2, errorPath);
}
}
@ -1288,6 +1279,9 @@ void CheckCondition::alwaysTrueFalse()
if (!(constIfWhileExpression || constValExpr || compExpr || returnStatement))
continue;
if (returnStatement && scope->function && !Token::simpleMatch(scope->function->retDef, "bool"))
continue;
if (returnStatement && isConstVarExpression(tok))
continue;
@ -1298,10 +1292,6 @@ void CheckCondition::alwaysTrueFalse()
!isVariableChanged(tok->variable(), mSettings, mTokenizer->isCPP())))
continue;
// FIXME checking of return statements does not work well. See #8801
if (returnStatement)
continue;
// Don't warn in assertions. Condition is often 'always true' by intention.
// If platform,defines,etc cause 'always false' then that is not dangerous neither.
bool assertFound = false;

38
test/testcondition.cpp
View File

@ -1656,6 +1656,12 @@ private:
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("int * f(int * x, int * y) {\n"
" if(!x) return x;\n"
" return y;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
}
void oppositeInnerConditionClass() {
@ -2069,18 +2075,30 @@ private:
"}\n");
ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (warning) Identical inner 'if' condition is always true.\n", errout.str());
check("bool f(bool a) {\n"
" if(a) { return a; }\n"
check("bool f(int a, int b) {\n"
" if(a == b) { return a == b; }\n"
" return false;\n"
"}\n");
ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:2]: (warning) Identical inner 'return' condition is always true.\n", errout.str());
check("bool f(bool a) {\n"
" if(a) { return a; }\n"
" return false;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("int* f(int* a, int * b) {\n"
" if(a) { return a; }\n"
" return b;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("int* f(std::shared_ptr<int> a, std::shared_ptr<int> b) {\n"
" if(a.get()) { return a.get(); }\n"
" return b.get();\n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("struct A { int * x; };\n"
"int* f(A a, int * b) {\n"
" if(a.x) { return a.x; }\n"
@ -2493,7 +2511,7 @@ private:
" if(x == 0) { x++; return x == 0; } \n"
" return false;\n"
"}");
TODO_ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:2]: (style) Condition 'x==0' is always false\n", "", errout.str());
ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:2]: (style) Condition 'x==0' is always false\n", errout.str());
check("void f() {\n" // #6898 (Token::expressionString)
" int x = 0;\n"
@ -2611,19 +2629,31 @@ private:
"}\n");
ASSERT_EQUALS("", errout.str());
check("int f(void){return 1/abs(10);}");
ASSERT_EQUALS("", errout.str());
check("bool f() { \n"
" int x = 0;\n"
" return x; \n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("int f() {\n"
check("bool f() {\n"
" const int a = 50;\n"
" const int b = 52;\n"
" return a+b;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("int f() {\n"
" int a = 50;\n"
" int b = 52;\n"
" a++;\n"
" b++;\n"
" return a+b;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("bool& g();\n"
"bool f() {\n"
" bool & b = g();\n"