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CheckUninitVar: Improving multi-variable value handling

This commit is contained in:
Daniel Marjamäki 2015-11-18 14:56:45 +01:00
parent d0e1583f20
commit e6ceae213e
1 changed files with 38 additions and 16 deletions
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54
lib/checkuninitvar.cpp
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@ -171,7 +171,29 @@ void CheckUninitVar::checkStruct(const Token *tok, const Variable &structvar)
}
}
static void conditionAlwaysTrueOrFalse(const Token *tok, const std::map<unsigned int, int> &variableValue, bool *alwaysTrue, bool *alwaysFalse)
struct VariableValue {
VariableValue() : not(false), value(0) {}
VariableValue(MathLib::bigint value) : not(false), value(value) {}
static VariableValue createNot(MathLib::bigint val) {
VariableValue ret = val;
ret.not = true;
return ret;
}
bool not;
MathLib::bigint value;
};
static bool operator==(const VariableValue & v, MathLib::bigint i)
{
return v.not ? (i != v.value) : (i == v.value);
}
static bool operator!=(const VariableValue & v, MathLib::bigint i)
{
return !(v==i);
}
static void conditionAlwaysTrueOrFalse(const Token *tok, const std::map<unsigned int, VariableValue> &variableValue, bool *alwaysTrue, bool *alwaysFalse)
{
assert(Token::simpleMatch(tok, "if ("));
@ -183,7 +205,7 @@ static void conditionAlwaysTrueOrFalse(const Token *tok, const std::map<unsigned
while (Token::Match(vartok, "%name% . %name%"))
vartok = vartok->tokAt(2);
std::map<unsigned int, int>::const_iterator it = variableValue.find(vartok->varId());
std::map<unsigned int, VariableValue>::const_iterator it = variableValue.find(vartok->varId());
if (it == variableValue.end())
return;
@ -250,8 +272,7 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
return true;
// variable values
std::map<unsigned int, int> variableValue;
static const int NOT_ZERO = (1<<30); // special variable value
std::map<unsigned int, VariableValue> variableValue;
for (; tok; tok = tok->next()) {
// End of scope..
@ -279,7 +300,7 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
// assignment with nonzero constant..
if (Token::Match(tok->previous(), "[;{}] %var% = - %name% ;"))
variableValue[tok->varId()] = NOT_ZERO;
variableValue[tok->varId()] = VariableValue::createNot(0);
// Inner scope..
else if (Token::simpleMatch(tok, "if (")) {
@ -293,16 +314,17 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
return true;
// checking if a not-zero variable is zero => bail out
unsigned int condVarId = 0, condVarValue = 0;
unsigned int condVarId = 0;
VariableValue condVarValue(0);
const Token *condVarTok = nullptr;
if (Token::simpleMatch(tok, "if (") &&
astIsVariableComparison(tok->next()->astOperand2(), "!=", "0", &condVarTok)) {
std::map<unsigned int,int>::const_iterator it = variableValue.find(condVarTok->varId());
if (it != variableValue.end() && it->second == NOT_ZERO)
std::map<unsigned int,VariableValue>::const_iterator it = variableValue.find(condVarTok->varId());
if (it != variableValue.end() && it->second != 0)
return true; // this scope is not fully analysed => return true
else {
condVarId = condVarTok->varId();
condVarValue = NOT_ZERO;
condVarValue = VariableValue::createNot(0);
}
}
@ -336,18 +358,18 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
if (alwaysTrue && noreturnIf)
return true;
std::map<unsigned int, int> varValueIf;
std::map<unsigned int, VariableValue> varValueIf;
if (!alwaysFalse && !initif && !noreturnIf) {
for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "[;{}.] %name% = - %name% ;"))
varValueIf[tok2->next()->varId()] = NOT_ZERO;
varValueIf[tok2->next()->varId()] = VariableValue::createNot(0);
else if (Token::Match(tok2, "[;{}.] %name% = %num% ;"))
varValueIf[tok2->next()->varId()] = (int)MathLib::toLongNumber(tok2->strAt(3));
varValueIf[tok2->next()->varId()] = MathLib::toLongNumber(tok2->strAt(3));
}
}
if (initif && condVarId > 0U)
variableValue[condVarId] = condVarValue ^ NOT_ZERO;
variableValue[condVarId] = condVarValue.not ? VariableValue(condVarValue.value) : VariableValue::createNot(condVarValue.value);
// goto the }
tok = tok->link();
@ -366,13 +388,13 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
bool noreturnElse = false;
const bool initelse = !alwaysTrue && checkScopeForVariable(tok->next(), var, &possibleInitElse, &noreturnElse, alloc, membervar);
std::map<unsigned int, int> varValueElse;
std::map<unsigned int, VariableValue> varValueElse;
if (!alwaysTrue && !initelse && !noreturnElse) {
for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "[;{}.] %var% = - %name% ;"))
varValueElse[tok2->next()->varId()] = NOT_ZERO;
varValueElse[tok2->next()->varId()] = VariableValue::createNot(0);
else if (Token::Match(tok2, "[;{}.] %var% = %num% ;"))
varValueElse[tok2->next()->varId()] = (int)MathLib::toLongNumber(tok2->strAt(3));
varValueElse[tok2->next()->varId()] = MathLib::toLongNumber(tok2->strAt(3));
}
}