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Fix issue 9833: False positive: Division by zero when using pointer to struct

This commit is contained in:
Paul 2020-09-09 21:29:26 -05:00
parent 48a6852a4a
commit 75b955b9c6
4 changed files with 37 additions and 24 deletions
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6
lib/forwardanalyzer.cpp
View File

@ -12,6 +12,7 @@ struct ForwardTraversal {
enum class Progress { Continue, Break, Skip };
ValuePtr<ForwardAnalyzer> analyzer;
const Settings* settings;
ForwardAnalyzer::Action actions;
std::pair<bool, bool> evalCond(const Token* tok) {
std::vector<int> result = analyzer->evaluate(tok);
@ -115,6 +116,7 @@ struct ForwardTraversal {
Progress update(Token* tok) {
ForwardAnalyzer::Action action = analyzer->analyze(tok);
actions |= action;
if (!action.isNone())
analyzer->update(tok, action);
if (action.isInconclusive() && !analyzer->lowerToInconclusive())
@ -225,6 +227,7 @@ struct ForwardTraversal {
allAnalysis |= analyzeRecursive(initTok);
if (stepTok)
allAnalysis |= analyzeRecursive(stepTok);
actions |= allAnalysis;
if (allAnalysis.isInconclusive()) {
if (!analyzer->lowerToInconclusive())
return Progress::Break;
@ -552,8 +555,9 @@ struct ForwardTraversal {
};
void valueFlowGenericForward(Token* start, const Token* end, const ValuePtr<ForwardAnalyzer>& fa, const Settings* settings)
ForwardAnalyzer::Action valueFlowGenericForward(Token* start, const Token* end, const ValuePtr<ForwardAnalyzer>& fa, const Settings* settings)
{
ForwardTraversal ft{fa, settings};
ft.updateRange(start, end);
return ft.actions;
}

2
lib/forwardanalyzer.h
View File

@ -113,6 +113,6 @@ struct ForwardAnalyzer {
virtual ~ForwardAnalyzer() {}
};
void valueFlowGenericForward(Token* start, const Token* end, const ValuePtr<ForwardAnalyzer>& fa, const Settings* settings);
ForwardAnalyzer::Action valueFlowGenericForward(Token* start, const Token* end, const ValuePtr<ForwardAnalyzer>& fa, const Settings* settings);
#endif

43
lib/valueflow.cpp
View File

@ -1710,7 +1710,7 @@ static void valueFlowGlobalStaticVar(TokenList *tokenList, const Settings *setti
}
}
static void valueFlowForwardVariable(Token* const startToken,
static ForwardAnalyzer::Action valueFlowForwardVariable(Token* const startToken,
const Token* const endToken,
const Variable* const var,
std::list<ValueFlow::Value> values,
@ -2697,7 +2697,7 @@ static std::vector<const Variable*> getAliasesFromValues(std::list<ValueFlow::Va
return aliases;
}
static void valueFlowForwardVariable(Token* const startToken,
static ForwardAnalyzer::Action valueFlowForwardVariable(Token* const startToken,
const Token* const endToken,
const Variable* const var,
std::list<ValueFlow::Value> values,
@ -2705,20 +2705,22 @@ static void valueFlowForwardVariable(Token* const startToken,
TokenList* const tokenlist,
const Settings* const settings)
{
ForwardAnalyzer::Action actions;
for (ValueFlow::Value& v : values) {
VariableForwardAnalyzer a(var, v, aliases, tokenlist);
valueFlowGenericForward(startToken, endToken, a, settings);
actions |= valueFlowGenericForward(startToken, endToken, a, settings);
}
return actions;
}
static void valueFlowForwardVariable(Token* const startToken,
static ForwardAnalyzer::Action valueFlowForwardVariable(Token* const startToken,
const Token* const endToken,
const Variable* const var,
std::list<ValueFlow::Value> values,
TokenList* const tokenlist,
const Settings* const settings)
{
valueFlowForwardVariable(startToken, endToken, var, std::move(values), getAliasesFromValues(values), tokenlist, settings);
return valueFlowForwardVariable(startToken, endToken, var, std::move(values), getAliasesFromValues(values), tokenlist, settings);
}
// Old deprecated version
@ -2805,17 +2807,19 @@ struct ExpressionForwardAnalyzer : SingleValueFlowForwardAnalyzer {
}
};
static void valueFlowForwardExpression(Token* startToken,
static ForwardAnalyzer::Action valueFlowForwardExpression(Token* startToken,
const Token* endToken,
const Token* exprTok,
const std::list<ValueFlow::Value>& values,
const TokenList* const tokenlist,
const Settings* settings)
{
ForwardAnalyzer::Action actions;
for (const ValueFlow::Value& v : values) {
ExpressionForwardAnalyzer a(exprTok, v, tokenlist);
valueFlowGenericForward(startToken, endToken, a, settings);
actions |= valueFlowGenericForward(startToken, endToken, a, settings);
}
return actions;
}
static const Token* parseBinaryIntOp(const Token* expr, MathLib::bigint& known)
@ -2879,7 +2883,7 @@ static const Token* solveExprValues(const Token* expr, std::list<ValueFlow::Valu
return expr;
}
static void valueFlowForward(Token* startToken,
static ForwardAnalyzer::Action valueFlowForward(Token* startToken,
const Token* endToken,
const Token* exprTok,
std::list<ValueFlow::Value> values,
@ -2888,14 +2892,14 @@ static void valueFlowForward(Token* startToken,
{
const Token* expr = solveExprValues(exprTok, values);
if (expr->variable()) {
valueFlowForwardVariable(startToken,
return valueFlowForwardVariable(startToken,
endToken,
expr->variable(),
values,
tokenlist,
settings);
} else {
valueFlowForwardExpression(startToken, endToken, expr, values, tokenlist, settings);
return valueFlowForwardExpression(startToken, endToken, expr, values, tokenlist, settings);
}
}
@ -4554,9 +4558,7 @@ static void valueFlowAfterCondition(TokenList *tokenlist,
const Token* vartok,
const std::list<ValueFlow::Value>& values,
bool) {
valueFlowForward(start->next(), stop, vartok, values, tokenlist, settings);
std::vector<const Variable*> vars = getExprVariables(vartok, tokenlist, symboldatabase, settings);
return isVariablesChanged(start, stop, 0, vars, settings, tokenlist->isCPP());
return valueFlowForward(start->next(), stop, vartok, values, tokenlist, settings).isModified();
};
handler.parse = [&](const Token *tok) {
ValueFlowConditionHandler::Condition cond;
@ -5887,19 +5889,19 @@ struct ContainerVariableForwardAnalyzer : VariableForwardAnalyzer {
}
};
static void valueFlowContainerForward(Token *tok, const Token* endToken, const Variable* var, ValueFlow::Value value, TokenList *tokenlist)
static ForwardAnalyzer::Action valueFlowContainerForward(Token *tok, const Token* endToken, const Variable* var, ValueFlow::Value value, TokenList *tokenlist)
{
ContainerVariableForwardAnalyzer a(var, value, getAliasesFromValues({value}), tokenlist);
valueFlowGenericForward(tok, endToken, a, tokenlist->getSettings());
return valueFlowGenericForward(tok, endToken, a, tokenlist->getSettings());
}
static void valueFlowContainerForward(Token *tok, const Variable* var, ValueFlow::Value value, TokenList *tokenlist)
static ForwardAnalyzer::Action valueFlowContainerForward(Token *tok, const Variable* var, ValueFlow::Value value, TokenList *tokenlist)
{
const Token * endOfVarScope = nullptr;
if (var->isLocal() || var->isArgument())
endOfVarScope = var->scope()->bodyEnd;
if (!endOfVarScope)
endOfVarScope = tok->scope()->bodyEnd;
valueFlowContainerForward(tok, endOfVarScope, var, std::move(value), tokenlist);
return valueFlowContainerForward(tok, endOfVarScope, var, std::move(value), tokenlist);
}
static bool isContainerSizeChanged(const Token *tok, int depth)
@ -6053,9 +6055,7 @@ static void valueFlowIteratorAfterCondition(TokenList *tokenlist,
const Token* vartok,
const std::list<ValueFlow::Value>& values,
bool) {
valueFlowForward(start->next(), stop, vartok, values, tokenlist, settings);
std::vector<const Variable*> vars = getExprVariables(vartok, tokenlist, symboldatabase, settings);
return isVariablesChanged(start, stop, 0, vars, settings, tokenlist->isCPP());
return valueFlowForward(start->next(), stop, vartok, values, tokenlist, settings).isModified();
};
handler.parse = [&](const Token *tok) {
ValueFlowConditionHandler::Condition cond;
@ -6230,8 +6230,7 @@ static void valueFlowContainerAfterCondition(TokenList *tokenlist,
const Variable* var = vartok->variable();
if (!var)
return false;
valueFlowContainerForward(start->next(), stop, var, values.front(), tokenlist);
return isContainerSizeChanged(var->declarationId(), start, stop);
return valueFlowContainerForward(start->next(), stop, var, values.front(), tokenlist).isModified();
};
handler.parse = [&](const Token *tok) {
ValueFlowConditionHandler::Condition cond;

10
test/testother.cpp
View File

@ -697,6 +697,16 @@ private:
" a = b / -x;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
check("struct A {\n"
" int x;\n"
"};\n"
"int f(A* a) {\n"
" if (a->x == 0) \n"
" a->x = 1;\n"
" return 1/a->x;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
}
void nanInArithmeticExpression() {