[clang] 4affb2d - [analyzer] Use dynamic type when invalidating by a member function call (#111138)
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Thu Oct 24 04:22:22 PDT 2024
Author: Balazs Benics
Date: 2024-10-24T13:22:19+02:00
New Revision: 4affb2d59a541d8163404d7e21252b4686f1c3b8
URL: https://github.com/llvm/llvm-project/commit/4affb2d59a541d8163404d7e21252b4686f1c3b8
DIFF: https://github.com/llvm/llvm-project/commit/4affb2d59a541d8163404d7e21252b4686f1c3b8.diff
LOG: [analyzer] Use dynamic type when invalidating by a member function call (#111138)
When instantiating "callable<T>", the "class CallableType" nested type
will only have a declaration in the copy for the instantiation - because
it's not refereed to directly by any other code that would need a
complete definition.
However, in the past, when conservative eval calling member function, we
took the static type of the "this" expr, and looked up the CXXRecordDecl
it refereed to to see if it has any mutable members (to decide if it
needs to refine invalidation or not). Unfortunately, that query needs a
definition, and it asserts otherwise, thus we crashed.
To fix this, we should consult the dynamic type of the object, because
that will have the definition.
I anyways added a check for "hasDefinition" just to be on the safe side.
Fixes #77378
Added:
Modified:
clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h
clang/lib/StaticAnalyzer/Core/CallEvent.cpp
clang/test/Analysis/const-method-call.cpp
Removed:
################################################################################
diff --git a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h
index 549c864dc91ef2..4552df2a2a31e6 100644
--- a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h
+++ b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h
@@ -690,6 +690,11 @@ class CXXInstanceCall : public AnyFunctionCall {
ValueList &Values,
RegionAndSymbolInvalidationTraits *ETraits) const override;
+ /// Returns the decl refered to by the "dynamic type" of the current object
+ /// and if the class can be a sub-class or not.
+ /// If the Pointer is null, the flag has no meaning.
+ std::pair<const CXXRecordDecl *, bool> getDeclForDynamicType() const;
+
public:
/// Returns the expression representing the implicit 'this' object.
virtual const Expr *getCXXThisExpr() const { return nullptr; }
diff --git a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
index 0ead95083e0e3d..0fdef7487b9814 100644
--- a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -711,18 +711,17 @@ void CXXInstanceCall::getExtraInvalidatedValues(
if (const auto *D = cast_or_null<CXXMethodDecl>(getDecl())) {
if (!D->isConst())
return;
- // Get the record decl for the class of 'This'. D->getParent() may return a
- // base class decl, rather than the class of the instance which needs to be
- // checked for mutable fields.
- // TODO: We might as well look at the dynamic type of the object.
- const Expr *Ex = getCXXThisExpr()->IgnoreParenBaseCasts();
- QualType T = Ex->getType();
- if (T->isPointerType()) // Arrow or implicit-this syntax?
- T = T->getPointeeType();
- const CXXRecordDecl *ParentRecord = T->getAsCXXRecordDecl();
- assert(ParentRecord);
+
+ // Get the record decl for the class of 'This'. D->getParent() may return
+ // a base class decl, rather than the class of the instance which needs to
+ // be checked for mutable fields.
+ const CXXRecordDecl *ParentRecord = getDeclForDynamicType().first;
+ if (!ParentRecord || !ParentRecord->hasDefinition())
+ return;
+
if (ParentRecord->hasMutableFields())
return;
+
// Preserve CXXThis.
const MemRegion *ThisRegion = ThisVal.getAsRegion();
if (!ThisRegion)
@@ -748,6 +747,21 @@ SVal CXXInstanceCall::getCXXThisVal() const {
return ThisVal;
}
+std::pair<const CXXRecordDecl *, bool>
+CXXInstanceCall::getDeclForDynamicType() const {
+ const MemRegion *R = getCXXThisVal().getAsRegion();
+ if (!R)
+ return {};
+
+ DynamicTypeInfo DynType = getDynamicTypeInfo(getState(), R);
+ if (!DynType.isValid())
+ return {};
+
+ assert(!DynType.getType()->getPointeeType().isNull());
+ return {DynType.getType()->getPointeeCXXRecordDecl(),
+ DynType.canBeASubClass()};
+}
+
RuntimeDefinition CXXInstanceCall::getRuntimeDefinition() const {
// Do we have a decl at all?
const Decl *D = getDecl();
@@ -759,21 +773,7 @@ RuntimeDefinition CXXInstanceCall::getRuntimeDefinition() const {
if (!MD->isVirtual())
return AnyFunctionCall::getRuntimeDefinition();
- // Do we know the implicit 'this' object being called?
- const MemRegion *R = getCXXThisVal().getAsRegion();
- if (!R)
- return {};
-
- // Do we know anything about the type of 'this'?
- DynamicTypeInfo DynType = getDynamicTypeInfo(getState(), R);
- if (!DynType.isValid())
- return {};
-
- // Is the type a C++ class? (This is mostly a defensive check.)
- QualType RegionType = DynType.getType()->getPointeeType();
- assert(!RegionType.isNull() && "DynamicTypeInfo should always be a pointer.");
-
- const CXXRecordDecl *RD = RegionType->getAsCXXRecordDecl();
+ auto [RD, CanBeSubClass] = getDeclForDynamicType();
if (!RD || !RD->hasDefinition())
return {};
@@ -800,7 +800,7 @@ RuntimeDefinition CXXInstanceCall::getRuntimeDefinition() const {
// Does the decl that we found have an implementation?
const FunctionDecl *Definition;
if (!Result->hasBody(Definition)) {
- if (!DynType.canBeASubClass())
+ if (!CanBeSubClass)
return AnyFunctionCall::getRuntimeDefinition();
return {};
}
@@ -808,8 +808,9 @@ RuntimeDefinition CXXInstanceCall::getRuntimeDefinition() const {
// We found a definition. If we're not sure that this devirtualization is
// actually what will happen at runtime, make sure to provide the region so
// that ExprEngine can decide what to do with it.
- if (DynType.canBeASubClass())
- return RuntimeDefinition(Definition, R->StripCasts());
+ if (CanBeSubClass)
+ return RuntimeDefinition(Definition,
+ getCXXThisVal().getAsRegion()->StripCasts());
return RuntimeDefinition(Definition, /*DispatchRegion=*/nullptr);
}
diff --git a/clang/test/Analysis/const-method-call.cpp b/clang/test/Analysis/const-method-call.cpp
index 8e1fd3b125f0e2..7da7ca5554a23e 100644
--- a/clang/test/Analysis/const-method-call.cpp
+++ b/clang/test/Analysis/const-method-call.cpp
@@ -271,3 +271,49 @@ void checkThatConstMethodCallDoesInvalidateObjectForCircularReferences() {
// FIXME: Should be UNKNOWN.
clang_analyzer_eval(t.x); // expected-warning{{TRUE}}
}
+
+namespace gh77378 {
+template <typename Signature> class callable;
+
+template <typename R> class callable<R()> {
+ struct CallableType {
+ bool operator()();
+ };
+ using MethodType = R (CallableType::*)();
+ CallableType *object_{nullptr};
+ MethodType method_;
+
+public:
+ callable() = default;
+
+ template <typename T>
+ constexpr callable(const T &obj)
+ : object_{reinterpret_cast<CallableType *>(&const_cast<T &>(obj))},
+ method_{reinterpret_cast<MethodType>(
+ static_cast<bool (T::*)() const>(&T::operator()))} {}
+
+ constexpr bool const_method() const {
+ return (object_->*(method_))();
+ }
+
+ callable call() const & {
+ static const auto L = [this]() {
+ while (true) {
+ // This should not crash when conservative eval calling the member function
+ // when it unwinds the call stack due to exhausting the budget or reaching
+ // the inlining limit.
+ if (this->const_method()) {
+ break;
+ }
+ }
+ return true;
+ };
+ return L;
+ }
+};
+
+void entry() {
+ callable<bool()>{}.call().const_method();
+ // expected-warning at -1 {{Address of stack memory associated with temporary object of type 'callable<bool ()>' is still referred to by the static variable 'L' upon returning to the caller. This will be a dangling reference}}
+}
+} // namespace gh77378
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