================
@@ -3068,12 +3124,242 @@ void MallocChecker::checkDeadSymbols(SymbolReaper
&SymReaper,
C.addTransition(state->set<RegionState>(RS), N);
}
+// Helper function to check if a name is a recognized smart pointer name
+static bool isSmartPtrName(StringRef Name) {
+ return Name == "unique_ptr" || Name == "shared_ptr";
+}
+
+// Allowlist of owning smart pointers we want to recognize.
+// Start with unique_ptr and shared_ptr. (intentionally exclude weak_ptr)
+static bool isSmartOwningPtrType(QualType QT) {
+ QT = QT->getCanonicalTypeUnqualified();
+
+ // First try TemplateSpecializationType (for std smart pointers)
+ if (const auto *TST = QT->getAs<TemplateSpecializationType>()) {
+ const TemplateDecl *TD = TST->getTemplateName().getAsTemplateDecl();
+ if (!TD)
+ return false;
+
+ const auto *ND = dyn_cast_or_null<NamedDecl>(TD->getTemplatedDecl());
+ if (!ND)
+ return false;
+
+ // Check if it's in std namespace
+ if (!isWithinStdNamespace(ND))
+ return false;
+
+ return isSmartPtrName(ND->getName());
+ }
+
+ // Also try RecordType (for custom smart pointer implementations)
+ if (const auto *RD = QT->getAsCXXRecordDecl()) {
+ // Accept any custom unique_ptr or shared_ptr implementation
+ return isSmartPtrName(RD->getName());
+ }
+
+ return false;
+}
+
+/// Check if a record type has smart pointer fields (directly or in base
+/// classes).
+static bool hasSmartPtrField(const CXXRecordDecl *CRD) {
+ // Check direct fields
+ if (llvm::any_of(CRD->fields(), [](const FieldDecl *FD) {
+ return isSmartOwningPtrType(FD->getType());
+ }))
+ return true;
+
+ // Check fields from base classes
+ for (const CXXBaseSpecifier &Base : CRD->bases()) {
+ if (const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl()) {
+ if (hasSmartPtrField(BaseDecl))
+ return true;
+ }
+ }
+ return false;
+}
+
+/// Check if an expression is an rvalue record type passed by value.
+static bool isRvalueByValueRecord(const Expr *AE) {
+ if (AE->isGLValue())
+ return false;
+
+ QualType T = AE->getType();
+ if (!T->isRecordType() || T->isReferenceType())
+ return false;
+
+ // Accept common temp/construct forms but don't overfit.
+ return isa<CXXTemporaryObjectExpr, MaterializeTemporaryExpr,
CXXConstructExpr,
+ InitListExpr, ImplicitCastExpr, CXXBindTemporaryExpr>(AE);
+}
+
+/// Check if an expression is an rvalue record with smart pointer fields passed
+/// by value.
+static bool isRvalueByValueRecordWithSmartPtr(const Expr *AE) {
+ if (!isRvalueByValueRecord(AE))
+ return false;
+
+ const auto *CRD = AE->getType()->getAsCXXRecordDecl();
+ return CRD && hasSmartPtrField(CRD);
+}
+
+/// Check if a CXXRecordDecl has a name matching recognized smart pointer
names.
+static bool isSmartOwningPtrRecord(const CXXRecordDecl *RD) {
+ if (!RD)
+ return false;
+
+ // Check the record name directly
+ if (isSmartPtrName(RD->getName())) {
+ // Accept both std and custom smart pointer implementations
+ return true;
+ }
+
+ return false;
+}
+
+/// Check if a call is a constructor of a smart pointer class that accepts
+/// pointer parameters.
+static bool isSmartPtrCall(const CallEvent &Call) {
+ // Only check for smart pointer constructor calls
+ const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(Call.getDecl());
+ if (!CD)
+ return false;
+
+ const auto *RD = CD->getParent();
+ if (!isSmartOwningPtrRecord(RD))
+ return false;
+
+ // Check if constructor takes a pointer parameter
+ for (const auto *Param : CD->parameters()) {
+ QualType ParamType = Param->getType();
+ if (ParamType->isPointerType() && !ParamType->isFunctionPointerType() &&
+ !ParamType->isVoidPointerType()) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static void collectSmartOwningPtrFieldRegions(
----------------
NagyDonat wrote:
This function duplicates the traversal logic which also appears in
`hasSmartPtrField`, and I fear that it would be troublesome to preserve
consistency between them. (Note that there are already some inconsistencies: as
far as I see it's possible that `hasSmartPtrField` returns `true` but
`collectSmartOwningPtrFieldRegions` doesn't find any regions. This is not
necessarily a problem, but the code that uses these functions must be careful
to cover it.)
I can imagine three potential solutions for this problem:
1. Placing comments like `// WARNING: Keep the traversal in this function in
sync with ...` at the beginning of these two functions. Not elegant, but I can
accept this if you don't like the other options.
2. Eliminating the preliminary traversal step which is performed by
`hasSmartPtrField` slightly before calling `collectSmartOwningPtrFieldRegions`.
This would significantly simplify the logic – you won't need to do the same
traversal twice – but could potentially worsen the (performance if the
preliminary traversal step lets us avoid constructing the base object regions).
I strongly suspect that this performance loss is negligible, especially if we
compare it to the overall analyzer runtime, so – referring to "Premature
optimization is the root of all evil." – I'd primarily suggest this approach.
3. I also tried to refactor these two functions to ensure that they share the
same "core logic" which can optionally pass along a context struct object:
```c++
struct FieldConsumer {
const MemRegion *Base;
CheckerContext &C;
llvm::SmallPtrSetImpl<const MemRegion *> &Out;
void consume(const FieldDecl *FD) {
SVal L = C.getState()->getLValue(FD, loc::MemRegionVal(Base));
if (const MemRegion *FR = L.getAsRegion())
Out.insert(FR);
}
std::optional<FieldConsumer> switchToBase(const CXXRecordDecl *BaseDecl, bool
IsVirtual) {
// Get the base class region
SVal BaseL = C.getState()->getLValue(BaseDecl, Base->getAs<SubRegion>(),
IsVirtual);
if (const MemRegion *BaseRegion = BaseL.getAsRegion()) {
// Return a consumer
return FieldConsumer{BaseRegion, C, Out};
}
return std::nullopt;
}
};
static bool hasSmartPtrField(const CXXRecordDecl *CRD,
std::optional<FieldConsumer> FC = std::nullopt) {
for (const FieldDecl *FD : CRD->fields()) {
if (isSmartOwningPtrType(FD->getType())) {
if (!FC)
return true;
FC->consume(FD);
}
}
// Collect fields from base classes
for (const CXXBaseSpecifier &BaseSpec : CRD->bases()) {
if (const CXXRecordDecl *BaseDecl =
BaseSpec.getType()->getAsCXXRecordDecl()) {
std::optional<FieldConsumer> NewFC;
if (FC) {
NewFC = FC->switchToBase(BaseDecl, BaseSpec.isVirtual());
if (!NewFC)
continue;
}
bool Found = hasSmartPtrField(BaseDecl, NewFC);
if (Found && !FC)
return true;
}
}
return false;
}
static void collectSmartOwningPtrFieldRegions(const MemRegion *Base, QualType
RecQT,
CheckerContext &C, llvm::SmallPtrSetImpl<const MemRegion *> &Out) {
if (!Base)
return;
const auto *CRD = RecQT->getAsCXXRecordDecl();
if (!CRD)
return;
FieldConsumer FC{Base, C, Out};
hasSmartPtrField(CRD, FC);
}
```
[Disclaimer: I wrote this code in the browser, so it probably contains some
typos.] I feel that this is a bit too verbose, but I would still prefer this
over the status quo, because I value the maintainability highly (I wouldn't
like to troubleshoot bugs introduced by a discrepancy between these two
functions).
https://github.com/llvm/llvm-project/pull/152751
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