RedDocMD updated this revision to Diff 351628.
RedDocMD added a comment.
Fixed up technique used to find inner pointer type, put TODO's
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D103750/new/
https://reviews.llvm.org/D103750
Files:
clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
clang/test/Analysis/Inputs/system-header-simulator-cxx.h
clang/test/Analysis/smart-ptr-text-output.cpp
Index: clang/test/Analysis/smart-ptr-text-output.cpp
===================================================================
--- clang/test/Analysis/smart-ptr-text-output.cpp
+++ clang/test/Analysis/smart-ptr-text-output.cpp
@@ -1,3 +1,8 @@
+// RUN: %clang_analyze_cc1\
+// RUN: -analyzer-checker=core,cplusplus.Move,alpha.cplusplus.SmartPtr\
+// RUN: -analyzer-config cplusplus.SmartPtrModeling:ModelSmartPtrDereference=true\
+// RUN: -analyzer-output=text -std=c++20 %s -verify=expected
+
// RUN: %clang_analyze_cc1\
// RUN: -analyzer-checker=core,cplusplus.Move,alpha.cplusplus.SmartPtr\
// RUN: -analyzer-config cplusplus.SmartPtrModeling:ModelSmartPtrDereference=true\
@@ -313,3 +318,27 @@
// expected-note@-1{{Dereference of null smart pointer 'P'}}
}
}
+
+void makeUniqueReturnsNonNullUniquePtr() {
+ auto P = std::make_unique<A>();
+ if (!P) { // expected-note {{Taking false branch}}
+ P->foo(); // should have no warning here, path is impossible
+ }
+ P.reset(); // expected-note {{Smart pointer 'P' reset using a null value}}
+ // Now P is null
+ if (!P) {
+ // expected-note@-1 {{Taking true branch}}
+ P->foo(); // expected-warning {{Dereference of null smart pointer 'P' [alpha.cplusplus.SmartPtr]}}
+ // expected-note@-1{{Dereference of null smart pointer 'P'}}
+ }
+}
+
+#if __cplusplus >= 202002L
+
+void makeUniqueForOverwriteReturnsNullUniquePtr() {
+ auto P = std::make_unique_for_overwrite<A>(); // expected-note {{std::unique_ptr 'P' constructed by std::make_unique_for_overwrite is null}}
+ *P; // expected-warning {{Dereference of null smart pointer 'P' [alpha.cplusplus.SmartPtr]}}
+ // expected-note@-1{{Dereference of null smart pointer 'P'}}
+}
+
+#endif
Index: clang/test/Analysis/Inputs/system-header-simulator-cxx.h
===================================================================
--- clang/test/Analysis/Inputs/system-header-simulator-cxx.h
+++ clang/test/Analysis/Inputs/system-header-simulator-cxx.h
@@ -978,6 +978,17 @@
void swap(unique_ptr<T> &x, unique_ptr<T> &y) noexcept {
x.swap(y);
}
+
+template <class T, class... Args>
+unique_ptr<T> make_unique(Args &&...args);
+
+#if __cplusplus >= 202002L
+
+template <class T>
+unique_ptr<T> make_unique_for_overwrite();
+
+#endif
+
} // namespace std
#endif
Index: clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
+++ clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
@@ -35,6 +35,7 @@
using namespace ento;
namespace {
+
class SmartPtrModeling
: public Checker<eval::Call, check::DeadSymbols, check::RegionChanges,
check::LiveSymbols> {
@@ -76,6 +77,9 @@
{{"release"}, &SmartPtrModeling::handleRelease},
{{"swap", 1}, &SmartPtrModeling::handleSwap},
{{"get"}, &SmartPtrModeling::handleGet}};
+ const CallDescription StdMakeUniqueCall{{"std", "make_unique"}};
+ const CallDescription StdMakeUniqueForOverwriteCall{
+ {"std", "make_unique_for_overwrite"}};
};
} // end of anonymous namespace
@@ -135,6 +139,21 @@
return State;
}
+// This is for use with standalone-functions like std::make_unique,
+// std::make_unique_for_overwrite, etc. It reads the template parameter and
+// returns the pointer type corresponding to it,
+static QualType getPointerTypeFromTemplateArg(const CallEvent &Call,
+ CheckerContext &C) {
+ const auto *FD = dyn_cast_or_null<FunctionDecl>(Call.getDecl());
+ if (!FD || !FD->isFunctionTemplateSpecialization())
+ return {};
+ const auto &TemplateArgs = FD->getTemplateSpecializationArgs()->asArray();
+ if (TemplateArgs.size() == 0)
+ return {};
+ auto ValueType = TemplateArgs[0].getAsType();
+ return C.getASTContext().getPointerType(ValueType.getCanonicalType());
+}
+
// Helper method to get the inner pointer type of specialized smart pointer
// Returns empty type if not found valid inner pointer type.
static QualType getInnerPointerType(const CallEvent &Call, CheckerContext &C) {
@@ -177,7 +196,60 @@
bool SmartPtrModeling::evalCall(const CallEvent &Call,
CheckerContext &C) const {
+
ProgramStateRef State = C.getState();
+
+ if (Call.isCalled(StdMakeUniqueCall)) {
+ const Optional<SVal> ThisRegionOpt = Call.getReturnValueUnderConstruction();
+ if (!ThisRegionOpt)
+ return false;
+
+ const auto PtrVal = C.getSValBuilder().conjureSymbolVal(
+ Call.getOriginExpr(), C.getLocationContext(),
+ getPointerTypeFromTemplateArg(Call, C), C.blockCount());
+
+ const MemRegion *ThisRegion = ThisRegionOpt->getAsRegion();
+ State = State->set<TrackedRegionMap>(ThisRegion, PtrVal);
+ State = State->assume(PtrVal, true);
+
+ // TODO: ExprEngine should do this for us.
+ auto &Engine = State->getStateManager().getOwningEngine();
+ State = Engine.updateObjectsUnderConstruction(
+ *ThisRegionOpt, nullptr, State, C.getLocationContext(),
+ Call.getConstructionContext(), {});
+
+ // We don't leave a note here since it is guaranteed the
+ // unique_ptr from this call is non-null (hence is safe to de-reference).
+ C.addTransition(State);
+ return true;
+ }
+
+ if (Call.isCalled(StdMakeUniqueForOverwriteCall)) {
+ const Optional<SVal> ThisRegionOpt = Call.getReturnValueUnderConstruction();
+ if (!ThisRegionOpt)
+ return false;
+ const MemRegion *ThisRegion = ThisRegionOpt->getAsRegion();
+ const auto NullVal = C.getSValBuilder().makeNull();
+ State = State->set<TrackedRegionMap>(ThisRegion, NullVal);
+
+ // TODO: ExprEngine should do this for us.
+ auto &Engine = State->getStateManager().getOwningEngine();
+ State = Engine.updateObjectsUnderConstruction(
+ *ThisRegionOpt, nullptr, State, C.getLocationContext(),
+ Call.getConstructionContext(), {});
+
+ C.addTransition(State, C.getNoteTag([ThisRegion](PathSensitiveBugReport &BR,
+ llvm::raw_ostream &OS) {
+ if (&BR.getBugType() != smartptr::getNullDereferenceBugType() ||
+ !BR.isInteresting(ThisRegion))
+ return;
+ OS << "std::unique_ptr";
+ checkAndPrettyPrintRegion(OS, ThisRegion);
+ OS << " constructed by std::make_unique_for_overwrite is null";
+ }));
+ return true;
+ }
+
if (!smartptr::isStdSmartPtrCall(Call))
return false;
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