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Fixed #4511 (False positive: uninitialized struct member)

This commit is contained in:
Daniel Marjamäki 2013-01-25 18:20:57 +01:00
parent 3b08b410a2
commit ae43b12bf1
2 changed files with 57 additions and 16 deletions
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64
lib/checkuninitvar.cpp
View File

@ -1102,6 +1102,47 @@ void CheckUninitVar::checkScope(const Scope* scope)
}
}
static void conditionAlwaysTrueOrFalse(const Token *tok, const std::map<unsigned int, int> &variableValue, bool *alwaysTrue, bool *alwaysFalse)
{
assert(Token::Match(tok, "if ("));
const Token *vartok = tok->tokAt(2);
const bool NOT(vartok->str() == "!");
if (NOT)
vartok = vartok->next();
while (Token::Match(vartok, "%var% . %var%"))
vartok = vartok->tokAt(2);
std::map<unsigned int, int>::const_iterator it = variableValue.find(vartok->varId());
if (it == variableValue.end())
return;
// always true
if (Token::Match(vartok, "%var% %oror%|)")) {
if (NOT)
*alwaysTrue = bool(it->second == 0);
else
*alwaysTrue = bool(it->second != 0);
} else if (Token::Match(vartok, "%var% == %num% %or%|)")) {
*alwaysTrue = bool(it->second == MathLib::toLongNumber(vartok->strAt(2)));
} else if (Token::Match(vartok, "%var% != %num% %or%|)")) {
*alwaysTrue = bool(it->second != MathLib::toLongNumber(vartok->strAt(2)));
}
// always false
if (Token::Match(vartok, "%var% &&|)")) {
if (NOT)
*alwaysFalse = bool(it->second == 0);
else
*alwaysFalse = bool(it->second != 0);
} else if (Token::Match(vartok, "%var% == %num% &&|)")) {
*alwaysFalse = bool(it->second != MathLib::toLongNumber(vartok->strAt(2)));
} else if (Token::Match(vartok, "%var% != %num% &&|)")) {
*alwaysFalse = bool(it->second == MathLib::toLongNumber(vartok->strAt(2)));
}
}
bool CheckUninitVar::checkScopeForVariable(const Scope* scope, const Token *tok, const Variable& var, bool * const possibleInit, bool * const noreturn, const std::string &membervar)
{
const bool suppressErrors(possibleInit && *possibleInit);
@ -1143,18 +1184,9 @@ bool CheckUninitVar::checkScopeForVariable(const Scope* scope, const Token *tok,
// Inner scope..
if (Token::simpleMatch(tok, "if (")) {
bool alwaysTrue = false;
bool alwaysFalse = false;
// known variable in condition..
if (Token::Match(tok, "if ( !| %var% %oror%")) {
const Token *vartok = tok->tokAt(2);
if (vartok->str() == "!")
vartok = vartok->next();
std::map<unsigned int, int>::const_iterator it = variableValue.find(vartok->varId());
if (tok->strAt(2) == "!")
alwaysTrue = bool(it != variableValue.end() && it->second == 0);
else
alwaysTrue = bool(it != variableValue.end() && it->second != 0);
}
conditionAlwaysTrueOrFalse(tok, variableValue, &alwaysTrue, &alwaysFalse);
// initialization / usage in condition..
if (!alwaysTrue && checkIfForWhileHead(scope, tok->next(), var, suppressErrors, bool(number_of_if == 0), membervar))
@ -1180,7 +1212,7 @@ bool CheckUninitVar::checkScopeForVariable(const Scope* scope, const Token *tok,
if (tok->str() == "{") {
bool possibleInitIf(number_of_if > 0 || suppressErrors);
bool noreturnIf = false;
const bool initif = !alwaysTrue && checkScopeForVariable(scope, tok->next(), var, &possibleInitIf, &noreturnIf, membervar);
const bool initif = !alwaysFalse && !alwaysTrue && checkScopeForVariable(scope, tok->next(), var, &possibleInitIf, &noreturnIf, membervar);
// bail out for such code:
// if (a) x=0; // conditional initialization
@ -1202,9 +1234,9 @@ bool CheckUninitVar::checkScopeForVariable(const Scope* scope, const Token *tok,
std::map<unsigned int, int> varValueIf;
if (!initif) {
for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "[;{}] %var% = - %var% ;"))
if (Token::Match(tok2, "[;{}.] %var% = - %var% ;"))
varValueIf[tok2->next()->varId()] = NOT_ZERO;
if (Token::Match(tok2, "[;{}] %var% = %num% ;"))
if (Token::Match(tok2, "[;{}.] %var% = %num% ;"))
varValueIf[tok2->next()->varId()] = (int)MathLib::toLongNumber(tok2->strAt(3));
}
}
@ -1232,9 +1264,9 @@ bool CheckUninitVar::checkScopeForVariable(const Scope* scope, const Token *tok,
std::map<unsigned int, int> varValueElse;
if (!initelse) {
for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "[;{}] %var% = - %var% ;"))
if (Token::Match(tok2, "[;{}.] %var% = - %var% ;"))
varValueElse[tok2->next()->varId()] = NOT_ZERO;
if (Token::Match(tok2, "[;{}] %var% = %num% ;"))
if (Token::Match(tok2, "[;{}.] %var% = %num% ;"))
varValueElse[tok2->next()->varId()] = (int)MathLib::toLongNumber(tok2->strAt(3));
}
}

9
test/testuninitvar.cpp
View File

@ -2230,6 +2230,15 @@ private:
"}\n");
ASSERT_EQUALS("", errout.str());
checkUninitVar2("struct AB { int a; int b; };\n"
"void f(void) {\n"
" struct AB ab;\n"
" if (x) ab = getAB();\n"
" else ab.a = 0;\n"
" if (ab.a == 1) b = ab.b;\n"
"}", "test.c");
ASSERT_EQUALS("", errout.str());
// asm
checkUninitVar2("void f() {\n"
" int x;\n"