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Add special function to match lifetimes (#5320) 

This also removes the termination checking in `valueFlowUninit` as this
causes a lot of FNs.
This commit is contained in:
Paul Fultz II 2023-08-14 03:27:00 -05:00 committed by GitHub
parent 48c91abba6
commit 52081ef08f
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 36 additions and 20 deletions
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4
lib/checkuninitvar.cpp
View File

@ -710,7 +710,9 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
if (!suppressErrors && Token::Match(tok, "%name% . %name%") && tok->strAt(2) == membervar && Token::Match(tok->next()->astParent(), "%cop%|return|throw|?"))
uninitStructMemberError(tok, tok->str() + "." + membervar);
else if (mTokenizer->isCPP() && !suppressErrors && Token::Match(tok, "%name%") && Token::Match(tok->astParent(), "return|throw|?")) {
if (std::any_of(tok->values().cbegin(), tok->values().cend(), std::mem_fn(&ValueFlow::Value::isUninitValue)))
if (std::any_of(tok->values().cbegin(), tok->values().cend(), [](const ValueFlow::Value& v) {
return v.isUninitValue() && !v.isInconclusive();
}))
uninitStructMemberError(tok, tok->str() + "." + membervar);
}
}

43
lib/valueflow.cpp
View File

@ -641,9 +641,10 @@ static void setTokenValue(Token* tok,
}
}
if (Token::simpleMatch(parent, "=") && astIsRHS(tok) && !value.isLifetimeValue()) {
setTokenValue(parent, std::move(value), settings);
return;
if (Token::simpleMatch(parent, "=") && astIsRHS(tok)) {
setTokenValue(parent, value, settings);
if (!value.isUninitValue())
return;
}
if (value.isContainerSizeValue() && astIsContainer(tok)) {
@ -2433,6 +2434,20 @@ struct ValueFlowAnalyzer : Analyzer {
return settings;
}
// Returns Action::Match if its an exact match, return Action::Read if it partially matches the lifetime
Action analyzeLifetime(const Token* tok) const
{
if (!tok)
return Action::None;
if (match(tok))
return Action::Match;
if (Token::simpleMatch(tok, ".") && analyzeLifetime(tok->astOperand1()) != Action::None)
return Action::Read;
if (astIsRHS(tok) && Token::simpleMatch(tok->astParent(), "."))
return analyzeLifetime(tok->astParent());
return Action::None;
}
struct ConditionState {
bool dependent = true;
bool unknown = true;
@ -2806,7 +2821,10 @@ struct ValueFlowAnalyzer : Analyzer {
return Action::None;
lifeTok = v.tokvalue;
}
if (lifeTok && match(lifeTok)) {
if (!lifeTok)
return Action::None;
Action la = analyzeLifetime(lifeTok);
if (la.matches()) {
Action a = Action::Read;
if (isModified(tok).isModified())
a = Action::Invalid;
@ -2816,6 +2834,9 @@ struct ValueFlowAnalyzer : Analyzer {
return Action::Inconclusive;
return a;
}
if (la.isRead()) {
return isAliasModified(tok);
}
return Action::None;
} else if (isAlias(ref, inconclusive)) {
@ -3299,12 +3320,6 @@ struct MemberExpressionAnalyzer : SubExpressionAnalyzer {
: SubExpressionAnalyzer(e, std::move(val), t, s), varname(std::move(varname))
{}
bool match(const Token* tok) const override
{
return SubExpressionAnalyzer::match(tok) ||
(Token::simpleMatch(tok->astParent(), ".") && SubExpressionAnalyzer::match(tok->astParent()));
}
bool submatch(const Token* tok, bool exact) const override
{
if (!Token::Match(tok, ". %var%"))
@ -3334,6 +3349,8 @@ static std::string lifetimeType(const Token *tok, const ValueFlow::Value *val)
case ValueFlow::Value::LifetimeKind::Address:
if (astIsPointer(tok))
result = "pointer";
else if (Token::simpleMatch(tok, "=") && astIsPointer(tok->astOperand2()))
result = "pointer";
else
result = "object";
break;
@ -7977,7 +7994,6 @@ static void valueFlowUninit(TokenList& tokenlist, const Settings* settings)
Token* start = findStartToken(var, tok->next(), &settings->library);
std::map<Token*, ValueFlow::Value> partialReads;
Analyzer::Result result;
if (const Scope* scope = var->typeScope()) {
if (Token::findsimplematch(scope->bodyStart, "union", scope->bodyEnd))
continue;
@ -7992,7 +8008,7 @@ static void valueFlowUninit(TokenList& tokenlist, const Settings* settings)
continue;
}
MemberExpressionAnalyzer analyzer(memVar.nameToken()->str(), tok, uninitValue, tokenlist, settings);
result = valueFlowGenericForward(start, tok->scope()->bodyEnd, analyzer, *settings);
valueFlowGenericForward(start, tok->scope()->bodyEnd, analyzer, *settings);
for (auto&& p : *analyzer.partialReads) {
Token* tok2 = p.first;
@ -8022,8 +8038,7 @@ static void valueFlowUninit(TokenList& tokenlist, const Settings* settings)
if (partial)
continue;
if (result.terminate != Analyzer::Terminate::Modified)
valueFlowForward(start, tok->scope()->bodyEnd, var->nameToken(), uninitValue, tokenlist, settings);
valueFlowForward(start, tok->scope()->bodyEnd, var->nameToken(), uninitValue, tokenlist, settings);
}
}

9
test/testuninitvar.cpp
View File

@ -6209,7 +6209,7 @@ private:
" memcpy(wcsin, x, sizeof(wcsstruct));\n" // <- warning
" x->wcsprm = NULL;\n" // <- no warning
"}");
ASSERT_EQUALS("[test.cpp:7]: (error) Uninitialized variable: x.wcsprm\n", errout.str());
ASSERT_EQUALS("[test.cpp:7]: (error) Uninitialized variable: x\n", errout.str());
valueFlowUninit("struct wcsstruct {\n"
" int *wcsprm;\n"
@ -7037,8 +7037,7 @@ private:
" memcpy(in, s, sizeof(S));\n"
" s->p = NULL;\n"
"}\n");
ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: s.p\n",
errout.str());
ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: s\n", errout.str());
valueFlowUninit("struct S {\n" // #11321
" int a = 0;\n"
@ -7298,7 +7297,7 @@ private:
" A::B b;\n"
" x.push_back(b);\n"
"}\n");
ASSERT_EQUALS("[test.cpp:9]: (error) Uninitialized variable: b.i\n", errout.str());
ASSERT_EQUALS("[test.cpp:9]: (error) Uninitialized variable: b\n", errout.str());
valueFlowUninit("struct A {\n"
" struct B {\n"
@ -7322,7 +7321,7 @@ private:
" A a;\n"
" x.push_back(a);\n"
"}\n");
ASSERT_EQUALS("[test.cpp:9]: (error) Uninitialized variable: a.j\n", errout.str());
ASSERT_EQUALS("[test.cpp:9]: (error) Uninitialized variable: a\n", errout.str());
valueFlowUninit("struct S { struct T { int* p; } t[2]; };\n" // #11018
"void f() {\n"