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Fix #11774 (False positive: passing struct pointer to function that initialize it) #5162

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Merged
danmar merged 3 commits into from
Jun 16, 2023
Merged

Fix #11774 (False positive: passing struct pointer to function that initialize it) #5162

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e2f07bb
test
danmar Jun 16, 2023
e4bf25a
fix
danmar Jun 16, 2023
ad52a3a
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danmar Jun 16, 2023
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20 changes: 11 additions & 9 deletions lib/astutils.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2346,7 +2346,8 @@ bool isVariableChangedByFunctionCall(const Token *tok, int indirect, const Setti
const Token * const tok1 = tok;

// address of variable
if (tok->astParent() && tok->astParent()->isUnaryOp("&"))
const bool addressOf = tok->astParent() && tok->astParent()->isUnaryOp("&");
if (addressOf)
indirect++;

int argnr;
Expand Down Expand Up @@ -2408,6 +2409,8 @@ bool isVariableChangedByFunctionCall(const Token *tok, int indirect, const Setti
if (indirect > 0) {
if (arg->isPointer() && !(arg->valueType() && arg->valueType()->isConst(indirect)))
return true;
if (indirect > 1 && addressOf && arg->isPointer() && (!arg->valueType() || !arg->valueType()->isConst(indirect-1)))
return true;
if (arg->isArray() || (!arg->isPointer() && (!arg->valueType() || arg->valueType()->type == ValueType::UNKNOWN_TYPE)))
return true;
}
Expand Down Expand Up @@ -2482,16 +2485,15 @@ bool isVariableChanged(const Token *tok, int indirect, const Settings *settings,
}

const ValueType* vt = tok->variable() ? tok->variable()->valueType() : tok->valueType();
// If its already const then it cant be modified
if (vt) {
if (vt->isConst(indirect))
return false;
}

// Check addressof
if (tok2->astParent() && tok2->astParent()->isUnaryOp("&") &&
isVariableChanged(tok2->astParent(), indirect + 1, settings, depth - 1)) {
return true;
if (tok2->astParent() && tok2->astParent()->isUnaryOp("&")) {
if (isVariableChanged(tok2->astParent(), indirect + 1, settings, depth - 1))
return true;
} else {
// If its already const then it cant be modified
if (vt && vt->isConst(indirect))
return false;
}

if (cpp && Token::Match(tok2->astParent(), ">>|&") && astIsRHS(tok2) && isLikelyStreamRead(cpp, tok2->astParent()))
Expand Down
11 changes: 11 additions & 0 deletions test/testvalueflow.cpp
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Expand Up @@ -5543,6 +5543,17 @@ class TestValueFlow : public TestFixture {
"}";
values = tokenValues(code, "n )", ValueFlow::Value::ValueType::UNINIT);
ASSERT_EQUALS(0, values.size());

// #11774 - function call to init data
code = "struct id_struct { int id; };\n"
"int init(const id_struct **id);\n"
"void fp() {\n"
" const id_struct *id_st;\n"
" init(&id_st);\n"
" if (id_st->id > 0) {}\n"
"}\n";
values = tokenValues(code, ". id", ValueFlow::Value::ValueType::UNINIT);
ASSERT_EQUALS(0, values.size());
}

void valueFlowConditionExpressions() {
Expand Down