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Fix #11688 (FP uninitvar in for loop iteration expression) #5140

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Merged
danmar merged 1 commit into from
Jun 10, 2023
Merged

Fix #11688 (FP uninitvar in for loop iteration expression) #5140

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20 changes: 17 additions & 3 deletions lib/valueflow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7924,10 +7924,24 @@ static Token* findStartToken(const Variable* var, Token* start, const Library* l
Token* first = uses.front();
if (Token::findmatch(start, "goto|asm|setjmp|longjmp", first))
return start;
const Scope* scope = first->scope();
// If there is only one usage or the first usage is in the same scope
if (uses.size() == 1 || scope == var->scope())
// If there is only one usage
if (uses.size() == 1)
return first->previous();
const Scope* scope = first->scope();
// If first usage is in variable scope
if (scope == var->scope()) {
bool isLoopExpression = false;
for (const Token* parent = first; parent; parent = parent->astParent()) {
if (Token::simpleMatch(parent->astParent(), ";") &&
Token::simpleMatch(parent->astParent()->astParent(), ";") &&
Token::simpleMatch(parent->astParent()->astParent()->astParent(), "(") &&
Token::simpleMatch(parent->astParent()->astParent()->astParent()->astOperand1(), "for (") &&
parent == parent->astParent()->astParent()->astParent()->astOperand2()->astOperand2()->astOperand2()) {
isLoopExpression = true;
}
}
return isLoopExpression ? start : first->previous();
}
// If all uses are in the same scope
if (std::all_of(uses.begin() + 1, uses.end(), [&](const Token* tok) {
return tok->scope() == scope;
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13 changes: 11 additions & 2 deletions test/testvalueflow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5392,7 +5392,7 @@ class TestValueFlow : public TestFixture {
" int c;\n"
" if (d)\n"
" c = 0;\n"
" else if (e)\n"
" else if (e)\n"
" c = 0;\n"
" c++;\n"
"}\n";
Expand All @@ -5406,7 +5406,7 @@ class TestValueFlow : public TestFixture {
" int c;\n"
" if (d)\n"
" c = 0;\n"
" else if (!d)\n"
" else if (!d)\n"
" c = 0;\n"
" c++;\n"
"}\n";
Expand Down Expand Up @@ -5510,6 +5510,15 @@ class TestValueFlow : public TestFixture {
"}\n";
values = tokenValues(code, "i ++", ValueFlow::Value::ValueType::UNINIT);
ASSERT_EQUALS(0, values.size());

// #11688
code = "void f() {\n"
" int n;\n"
" for (int i = 0; i < 4; i = n)\n" // <- n is initialized in the loop body
" n = 10;\n"
"}";
values = tokenValues(code, "n )", ValueFlow::Value::ValueType::UNINIT);
ASSERT_EQUALS(0, values.size());
}

void valueFlowConditionExpressions() {
Expand Down