[clang] [analyzer] Add std::variant checker (PR #66481)
Gábor Spaits via cfe-commits
cfe-commits at lists.llvm.org
Thu Sep 21 02:57:29 PDT 2023
https://github.com/spaits updated https://github.com/llvm/llvm-project/pull/66481
>From 91bc14998e08c60c1e425f141dbcf44c8579d166 Mon Sep 17 00:00:00 2001
From: Gabor Spaits <gaborspaits1 at gmail.com>
Date: Fri, 15 Sep 2023 10:21:30 +0200
Subject: [PATCH] [analyzer] Add std::variant checker
Adding a checker that checks for bad std::variant type access.
---
.../clang/StaticAnalyzer/Checkers/Checkers.td | 4 +
.../StaticAnalyzer/Checkers/CMakeLists.txt | 1 +
.../Checkers/StdVariantChecker.cpp | 324 ++++++++++++++++
.../Checkers/TaggedUnionModeling.h | 104 ++++++
.../Inputs/system-header-simulator-cxx.h | 117 ++++++
.../diagnostics/explicit-suppression.cpp | 2 +-
clang/test/Analysis/std-variant-checker.cpp | 349 ++++++++++++++++++
7 files changed, 900 insertions(+), 1 deletion(-)
create mode 100644 clang/lib/StaticAnalyzer/Checkers/StdVariantChecker.cpp
create mode 100644 clang/lib/StaticAnalyzer/Checkers/TaggedUnionModeling.h
create mode 100644 clang/test/Analysis/std-variant-checker.cpp
diff --git a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
index 65c1595eb6245dd..052cf5f884f2773 100644
--- a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -318,6 +318,10 @@ def C11LockChecker : Checker<"C11Lock">,
Dependencies<[PthreadLockBase]>,
Documentation<HasDocumentation>;
+def StdVariantChecker : Checker<"StdVariant">,
+ HelpText<"Check for bad type access for std::variant.">,
+ Documentation<NotDocumented>;
+
} // end "alpha.core"
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt b/clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt
index ae849f59f90d3d9..d7cb51e1a0819a8 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt
+++ b/clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt
@@ -108,6 +108,7 @@ add_clang_library(clangStaticAnalyzerCheckers
SmartPtrModeling.cpp
StackAddrEscapeChecker.cpp
StdLibraryFunctionsChecker.cpp
+ StdVariantChecker.cpp
STLAlgorithmModeling.cpp
StreamChecker.cpp
StringChecker.cpp
diff --git a/clang/lib/StaticAnalyzer/Checkers/StdVariantChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StdVariantChecker.cpp
new file mode 100644
index 000000000000000..b5a75856e92ee31
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Checkers/StdVariantChecker.cpp
@@ -0,0 +1,324 @@
+//===- StdVariantChecker.cpp -------------------------------------*- C++ -*-==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/Type.h"
+#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Casting.h"
+#include <optional>
+#include <string_view>
+
+#include "TaggedUnionModeling.h"
+
+using namespace clang;
+using namespace ento;
+using namespace tagged_union_modeling;
+
+REGISTER_MAP_WITH_PROGRAMSTATE(VariantHeldTypeMap, const MemRegion *, QualType)
+
+namespace clang {
+namespace ento {
+namespace tagged_union_modeling {
+
+// Returns the CallEvent representing the caller of the function
+// It is needed because the CallEvent class does not contain enough information
+// to tell who called it. Checker context is needed.
+CallEventRef<> getCaller(const CallEvent &Call, const ProgramStateRef &State) {
+ const auto *CallLocationContext = Call.getLocationContext();
+ if (!CallLocationContext || CallLocationContext->inTopFrame())
+ return nullptr;
+
+ const auto *CallStackFrameContext = CallLocationContext->getStackFrame();
+ if (!CallStackFrameContext)
+ return nullptr;
+
+ CallEventManager &CEMgr = State->getStateManager().getCallEventManager();
+ return CEMgr.getCaller(CallStackFrameContext, State);
+}
+
+const CXXConstructorDecl *
+getConstructorDeclarationForCall(const CallEvent &Call) {
+ const auto *ConstructorCall = dyn_cast<CXXConstructorCall>(&Call);
+ if (!ConstructorCall)
+ return nullptr;
+
+ return ConstructorCall->getDecl();
+}
+
+bool isCopyConstructorCall(const CallEvent &Call) {
+ if (const CXXConstructorDecl *ConstructorDecl =
+ getConstructorDeclarationForCall(Call))
+ return ConstructorDecl->isCopyConstructor();
+ return false;
+}
+
+bool isCopyAssignmentCall(const CallEvent &Call) {
+ const Decl *CopyAssignmentDecl = Call.getDecl();
+
+ if (const auto *AsMethodDecl =
+ dyn_cast_or_null<CXXMethodDecl>(CopyAssignmentDecl))
+ return AsMethodDecl->isCopyAssignmentOperator();
+ return false;
+}
+
+bool isMoveConstructorCall(const CallEvent &Call) {
+ const CXXConstructorDecl *ConstructorDecl =
+ getConstructorDeclarationForCall(Call);
+ if (!ConstructorDecl)
+ return false;
+
+ return ConstructorDecl->isMoveConstructor();
+}
+
+bool isMoveAssignmentCall(const CallEvent &Call) {
+ const Decl *CopyAssignmentDecl = Call.getDecl();
+
+ const auto *AsMethodDecl =
+ dyn_cast_or_null<CXXMethodDecl>(CopyAssignmentDecl);
+ if (!AsMethodDecl)
+ return false;
+
+ return AsMethodDecl->isMoveAssignmentOperator();
+}
+
+bool isStdType(const Type *Type, llvm::StringRef TypeName) {
+ auto *Decl = Type->getAsRecordDecl();
+ if (!Decl)
+ return false;
+ return (Decl->getName() == TypeName) && Decl->isInStdNamespace();
+}
+
+bool isStdVariant(const Type *Type) {
+ return isStdType(Type, llvm::StringRef("variant"));
+}
+
+bool calledFromSystemHeader(const CallEvent &Call,
+ const ProgramStateRef &State) {
+ if (CallEventRef<> Caller = getCaller(Call, State))
+ return Caller->isInSystemHeader();
+
+ return false;
+}
+
+bool calledFromSystemHeader(const CallEvent &Call, CheckerContext &C) {
+ return calledFromSystemHeader(Call, C.getState());
+}
+
+} // end of namespace tagged_union_modeling
+} // end of namespace ento
+} // end of namespace clang
+
+static std::optional<ArrayRef<TemplateArgument>>
+getTemplateArgsFromVariant(const Type *VariantType) {
+ const auto *TempSpecType = VariantType->getAs<TemplateSpecializationType>();
+ if (!TempSpecType)
+ return {};
+
+ return TempSpecType->template_arguments();
+}
+
+static std::optional<QualType>
+getNthTemplateTypeArgFromVariant(const Type *varType, unsigned i) {
+ std::optional<ArrayRef<TemplateArgument>> VariantTemplates =
+ getTemplateArgsFromVariant(varType);
+ if (!VariantTemplates)
+ return {};
+
+ return (*VariantTemplates)[i].getAsType();
+}
+
+static bool isVowel(char a) {
+ switch (a) {
+ case 'a':
+ case 'e':
+ case 'i':
+ case 'o':
+ case 'u':
+ return true;
+ default:
+ return false;
+ }
+}
+
+static llvm::StringRef indefiniteArticleBasedOnVowel(char a) {
+ if (isVowel(a))
+ return "an";
+ return "a";
+}
+
+class StdVariantChecker : public Checker<eval::Call, check::RegionChanges> {
+ // Call descriptors to find relevant calls
+ CallDescription VariantConstructor{{"std", "variant", "variant"}};
+ CallDescription VariantAsOp{{"std", "variant", "operator="}};
+ CallDescription StdGet{{"std", "get"}, 1, 1};
+
+ BugType BadVariantType{this, "BadVariantType", "BadVariantType"};
+
+public:
+ ProgramStateRef checkRegionChanges(ProgramStateRef State,
+ const InvalidatedSymbols *,
+ ArrayRef<const MemRegion *>,
+ ArrayRef<const MemRegion *> Regions,
+ const LocationContext *,
+ const CallEvent *Call) const {
+ return removeInformationStoredForDeadInstances<VariantHeldTypeMap>(
+ Call, State, Regions);
+ }
+
+ bool evalCall(const CallEvent &Call, CheckerContext &C) const {
+ // Check if the call was not made from a system header. If it was then
+ // we do an early return because it is part of the implementation
+ if (calledFromSystemHeader(Call, C))
+ return false;
+
+ if (StdGet.matches(Call))
+ return handleStdGetCall(Call, C);
+
+ // First check if a constructor call is happening. If it is a
+ // constructor call, check if it is an std::variant constructor call.
+ bool IsVariantConstructor =
+ isa<CXXConstructorCall>(Call) && VariantConstructor.matches(Call);
+ bool IsVariantAssignmentOperatorCall =
+ isa<CXXMemberOperatorCall>(Call) && VariantAsOp.matches(Call);
+
+ if (IsVariantConstructor || IsVariantAssignmentOperatorCall) {
+ if (Call.getNumArgs() == 0 && IsVariantConstructor) {
+ handleDefaultConstructor(cast<CXXConstructorCall>(&Call), C);
+ return true;
+ }
+
+ if (Call.getNumArgs() != 1)
+ return false;
+
+ SVal ThisSVal;
+ if (IsVariantConstructor) {
+ const auto *AsConstructorCall = dyn_cast<CXXConstructorCall>(&Call);
+ ThisSVal = AsConstructorCall->getCXXThisVal();
+ } else if (IsVariantAssignmentOperatorCall) {
+ const auto *AsMemberOpCall = dyn_cast<CXXMemberOperatorCall>(&Call);
+ ThisSVal = AsMemberOpCall->getCXXThisVal();
+ } else {
+ return false;
+ }
+
+ handleConstructorAndAssignment<VariantHeldTypeMap>(Call, C, ThisSVal);
+ return true;
+ }
+ return false;
+ }
+
+private:
+ // The default constructed std::variant must be handled separately
+ // by default the std::variant is going to hold a default constructed instance
+ // of the first type of the possible types
+ void handleDefaultConstructor(const CXXConstructorCall *ConstructorCall,
+ CheckerContext &C) const {
+ SVal ThisSVal = ConstructorCall->getCXXThisVal();
+
+ const auto *const ThisMemRegion = ThisSVal.getAsRegion();
+ if (!ThisMemRegion)
+ return;
+
+ std::optional<QualType> DefaultType = getNthTemplateTypeArgFromVariant(
+ ThisSVal.getType(C.getASTContext())->getPointeeType().getTypePtr(), 0);
+ if (!DefaultType)
+ return;
+
+ ProgramStateRef State = ConstructorCall->getState();
+ State = State->set<VariantHeldTypeMap>(ThisMemRegion, *DefaultType);
+ C.addTransition(State);
+ }
+
+ bool handleStdGetCall(const CallEvent &Call, CheckerContext &C) const {
+ ProgramStateRef State = Call.getState();
+
+ const auto &ArgType = Call.getArgSVal(0)
+ .getType(C.getASTContext())
+ ->getPointeeType()
+ .getTypePtr();
+ // We have to make sure that the argument is an std::variant.
+ // There is another std::get with std::pair argument
+ if (!isStdVariant(ArgType))
+ return false;
+
+ // Get the mem region of the argument std::variant and get what type
+ // information is known about it.
+ const MemRegion *ArgMemRegion = Call.getArgSVal(0).getAsRegion();
+ const QualType *StoredType = State->get<VariantHeldTypeMap>(ArgMemRegion);
+ if (!StoredType)
+ return false;
+
+ const CallExpr *CE = cast<CallExpr>(Call.getOriginExpr());
+ const FunctionDecl *FD = CE->getDirectCallee();
+ if (FD->getTemplateSpecializationArgs()->size() < 1)
+ return false;
+
+ const auto &TypeOut = FD->getTemplateSpecializationArgs()->asArray()[0];
+ // std::get's first template parameter can be the type we want to get
+ // out of the std::variant or a natural number which is the position of
+ // the requested type in the argument type list of the std::variant's
+ // argument.
+ QualType RetrievedType;
+ switch (TypeOut.getKind()) {
+ case TemplateArgument::ArgKind::Type:
+ RetrievedType = TypeOut.getAsType();
+ break;
+ case TemplateArgument::ArgKind::Integral:
+ // In the natural number case we look up which type corresponds to the
+ // number.
+ if (std::optional<QualType> NthTemplate =
+ getNthTemplateTypeArgFromVariant(
+ ArgType, TypeOut.getAsIntegral().getSExtValue()))
+ RetrievedType = *NthTemplate;
+ else
+ return false;
+ break;
+ default:
+ return false;
+ }
+
+ QualType RetrievedCanonicalType = RetrievedType.getCanonicalType();
+ QualType StoredCanonicalType = StoredType->getCanonicalType();
+ if (RetrievedCanonicalType == StoredCanonicalType)
+ return true;
+
+ ExplodedNode *ErrNode = C.generateNonFatalErrorNode();
+ if (!ErrNode)
+ return false;
+ llvm::SmallString<128> Str;
+ llvm::raw_svector_ostream OS(Str);
+ std::string StoredTypeName = StoredType->getAsString();
+ std::string RetrievedTypeName = RetrievedType.getAsString();
+ OS << "std::variant " << ArgMemRegion->getDescriptiveName() << " held "
+ << indefiniteArticleBasedOnVowel(StoredTypeName[0]) << " \'"
+ << StoredTypeName << "\' not "
+ << indefiniteArticleBasedOnVowel(RetrievedTypeName[0]) << " \'"
+ << RetrievedTypeName << "\'";
+ auto R = std::make_unique<PathSensitiveBugReport>(BadVariantType, OS.str(),
+ ErrNode);
+ C.emitReport(std::move(R));
+ return true;
+ }
+};
+
+bool clang::ento::shouldRegisterStdVariantChecker(
+ clang::ento::CheckerManager const &mgr) {
+ return true;
+}
+
+void clang::ento::registerStdVariantChecker(clang::ento::CheckerManager &mgr) {
+ mgr.registerChecker<StdVariantChecker>();
+}
\ No newline at end of file
diff --git a/clang/lib/StaticAnalyzer/Checkers/TaggedUnionModeling.h b/clang/lib/StaticAnalyzer/Checkers/TaggedUnionModeling.h
new file mode 100644
index 000000000000000..593f243e84ca686
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Checkers/TaggedUnionModeling.h
@@ -0,0 +1,104 @@
+//===- TaggedUnionModeling.h -------------------------------------*- C++ -*-==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_STATICANALYZER_CHECKER_VARIANTLIKETYPEMODELING_H
+#define LLVM_CLANG_LIB_STATICANALYZER_CHECKER_VARIANTLIKETYPEMODELING_H
+
+#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "llvm/ADT/FoldingSet.h"
+#include <numeric>
+
+namespace clang {
+namespace ento {
+namespace tagged_union_modeling {
+
+// The implementation of all these functions can be found in the file
+// StdVariantChecker.cpp under the same directory as this file.
+CallEventRef<> getCaller(const CallEvent &Call, CheckerContext &C);
+bool isCopyConstructorCall(const CallEvent &Call);
+bool isCopyAssignmentCall(const CallEvent &Call);
+bool isMoveAssignmentCall(const CallEvent &Call);
+bool isMoveConstructorCall(const CallEvent &Call);
+bool isStdType(const Type *Type, const std::string &TypeName);
+bool isStdVariant(const Type *Type);
+bool calledFromSystemHeader(const CallEvent &Call, CheckerContext &C);
+
+// When invalidating regions, we also have to follow that by invalidating the
+// corresponding custom data in the program state.
+template <class TypeMap>
+ProgramStateRef
+removeInformationStoredForDeadInstances(const CallEvent *Call,
+ ProgramStateRef State,
+ ArrayRef<const MemRegion *> Regions) {
+ // If we do not know anything about the call we shall not continue.
+ // If the call is happens within a system header it is implementation detail.
+ // We should not take it into consideration.
+ if (!Call || Call->isInSystemHeader())
+ return State;
+
+ for (const MemRegion *Region : Regions)
+ State = State->remove<TypeMap>(Region);
+
+ return State;
+}
+
+template <class TypeMap>
+void handleConstructorAndAssignment(const CallEvent &Call, CheckerContext &C,
+ const SVal &ThisSVal) {
+ ProgramStateRef State = Call.getState();
+
+ if (!State)
+ return;
+
+ auto ArgSVal = Call.getArgSVal(0);
+ const auto *ThisRegion = ThisSVal.getAsRegion();
+ const auto *ArgMemRegion = ArgSVal.getAsRegion();
+
+ // Make changes to the state according to type of constructor/assignment
+ bool IsCopy = isCopyConstructorCall(Call) || isCopyAssignmentCall(Call);
+ bool IsMove = isMoveConstructorCall(Call) || isMoveAssignmentCall(Call);
+ // First we handle copy and move operations
+ if (IsCopy || IsMove) {
+ const QualType *OtherQType = State->get<TypeMap>(ArgMemRegion);
+
+ // If the argument of a copy constructor or assignment is unknown then
+ // we will not know the argument of the copied to object.
+ if (!OtherQType) {
+ State = State->remove<TypeMap>(ThisRegion);
+ } else {
+ // When move semantics is used we can only know that the moved from
+ // object must be in a destructible state. Other usage of the object
+ // than destruction is undefined.
+ if (IsMove)
+ State = State->remove<TypeMap>(ArgMemRegion);
+
+ State = State->set<TypeMap>(ThisRegion, *OtherQType);
+ }
+ } else {
+ // Value constructor
+ auto ArgQType = ArgSVal.getType(C.getASTContext());
+ const Type *ArgTypePtr = ArgQType.getTypePtr();
+
+ QualType WoPointer = ArgTypePtr->getPointeeType();
+ State = State->set<TypeMap>(ThisRegion, WoPointer);
+ }
+
+ C.addTransition(State);
+}
+
+} // namespace tagged_union_modeling
+} // namespace ento
+} // namespace clang
+
+#endif // LLVM_CLANG_LIB_STATICANALYZER_CHECKER_VARIANTLIKETYPEMODELING_H
\ No newline at end of file
diff --git a/clang/test/Analysis/Inputs/system-header-simulator-cxx.h b/clang/test/Analysis/Inputs/system-header-simulator-cxx.h
index 8633a8beadbff33..b1cb829268e3cb8 100644
--- a/clang/test/Analysis/Inputs/system-header-simulator-cxx.h
+++ b/clang/test/Analysis/Inputs/system-header-simulator-cxx.h
@@ -264,6 +264,9 @@ namespace std {
return static_cast<RvalRef>(a);
}
+ template< class T >
+ using remove_reference_t = typename remove_reference<T>::type;
+
template <class T>
void swap(T &a, T &b) {
T c(std::move(a));
@@ -718,6 +721,11 @@ namespace std {
template <class _Tp, class _Up> struct is_same : public false_type {};
template <class _Tp> struct is_same<_Tp, _Tp> : public true_type {};
+ #if __cplusplus >= 201703L
+ template< class T, class U >
+ inline constexpr bool is_same_v = is_same<T, U>::value;
+ #endif
+
template <class _Tp, bool = is_const<_Tp>::value || is_reference<_Tp>::value >
struct __add_const {typedef _Tp type;};
@@ -729,6 +737,9 @@ namespace std {
template <class _Tp> struct remove_const {typedef _Tp type;};
template <class _Tp> struct remove_const<const _Tp> {typedef _Tp type;};
+ template< class T >
+ using remove_const_t = typename remove_const<T>::type;
+
template <class _Tp> struct add_lvalue_reference {typedef _Tp& type;};
template <class _Tp> struct is_trivially_copy_assignable
@@ -793,6 +804,9 @@ namespace std {
return __result;
}
+ template< bool B, class T = void >
+ using enable_if_t = typename enable_if<B,T>::type;
+
template<class InputIter, class OutputIter>
OutputIter copy_backward(InputIter II, InputIter IE, OutputIter OI) {
return __copy_backward(II, IE, OI);
@@ -1252,4 +1266,107 @@ template <typename Ret, typename... Args> class packaged_task<Ret(Args...)> {
// TODO: Add some actual implementation.
};
+ #if __cplusplus >= 201703L
+
+ namespace detail
+ {
+ template<class T>
+ struct type_identity { using type = T; }; // or use std::type_identity (since C++20)
+
+ template<class T>
+ auto try_add_pointer(int) -> type_identity<typename std::remove_reference<T>::type*>;
+ template<class T>
+ auto try_add_pointer(...) -> type_identity<T>;
+ } // namespace detail
+
+ template<class T>
+ struct add_pointer : decltype(detail::try_add_pointer<T>(0)) {};
+
+ template< class T >
+ using add_pointer_t = typename add_pointer<T>::type;
+
+ template<class T> struct remove_cv { typedef T type; };
+ template<class T> struct remove_cv<const T> { typedef T type; };
+ template<class T> struct remove_cv<volatile T> { typedef T type; };
+ template<class T> struct remove_cv<const volatile T> { typedef T type; };
+
+ template< class T >
+ using remove_cv_t = typename remove_cv<T>::type;
+
+ // This decay does not behave exactly like std::decay, but this is enough
+ // for testing the std::variant checker
+ template<class T>
+ struct decay{typedef remove_cv_t<remove_reference_t<T>> type;};
+ template<class T>
+ using decay_t = typename decay<T>::type;
+
+ // variant
+ template <class... Types> class variant;
+ // variant helper classes
+ template <class T> struct variant_size;
+ template <class T> struct variant_size<const T>;
+ template <class T> struct variant_size<volatile T>;
+ template <class T> struct variant_size<const volatile T>;
+ template <class T> inline constexpr size_t variant_size_v = variant_size<T>::value;
+ template <class... Types>
+ struct variant_size<variant<Types...>>;
+ template <size_t I, class T> struct variant_alternative;
+ template <size_t I, class T> struct variant_alternative<I, const T>;
+ template <size_t I, class T> struct variant_alternative<I, volatile T>;
+ template <size_t I, class T> struct variant_alternative<I, const volatile T>;
+ template <size_t I, class T>
+ using variant_alternative_t = typename variant_alternative<I, T>::type;
+ template <size_t I, class... Types>
+ struct variant_alternative<I, variant<Types...>>;
+ inline constexpr size_t variant_npos = -1;
+ template <size_t I, class... Types>
+ constexpr variant_alternative_t<I, variant<Types...>>&
+ get(variant<Types...>&);
+ template <size_t I, class... Types>
+ constexpr variant_alternative_t<I, variant<Types...>>&&
+ get(variant<Types...>&&);
+ template <size_t I, class... Types>
+ constexpr const variant_alternative_t<I, variant<Types...>>&
+ get(const variant<Types...>&);
+ template <size_t I, class... Types>
+ constexpr const variant_alternative_t<I, variant<Types...>>&&
+ get(const variant<Types...>&&);
+ template <class T, class... Types>
+ constexpr T& get(variant<Types...>&);
+ template <class T, class... Types>
+ constexpr T&& get(variant<Types...>&&);
+ template <class T, class... Types>
+ constexpr const T& get(const variant<Types...>&);
+ template <class T, class... Types>
+ constexpr const T&& get(const variant<Types...>&&);
+ template <size_t I, class... Types>
+ constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>
+ get_if(variant<Types...>*) noexcept;
+ template <size_t I, class... Types>
+ constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>
+ get_if(const variant<Types...>*) noexcept;
+ template <class T, class... Types>
+ constexpr add_pointer_t<T> get_if(variant<Types...>*) noexcept;
+ template <class T, class... Types>
+ constexpr add_pointer_t<const T> get_if(const variant<Types...>*) noexcept;
+
+ template <class... Types>
+ class variant {
+ public:
+ // constructors
+ constexpr variant()= default ;
+ constexpr variant(const variant&);
+ constexpr variant(variant&&);
+ template<typename T,
+ typename = std::enable_if_t<!is_same_v<std::variant<Types...>, decay_t<T>>>>
+ constexpr variant(T&&);
+ // assignment
+ variant& operator=(const variant&);
+ variant& operator=(variant&&) ;
+ template<typename T,
+ typename = std::enable_if_t<!is_same_v<std::variant<Types...>, decay_t<T>>>>
+ variant& operator=(T&&);
+ };
+ #endif
+
} // namespace std
diff --git a/clang/test/Analysis/diagnostics/explicit-suppression.cpp b/clang/test/Analysis/diagnostics/explicit-suppression.cpp
index b98d0260b096594..ce1a02d1be0e500 100644
--- a/clang/test/Analysis/diagnostics/explicit-suppression.cpp
+++ b/clang/test/Analysis/diagnostics/explicit-suppression.cpp
@@ -19,6 +19,6 @@ class C {
void testCopyNull(C *I, C *E) {
std::copy(I, E, (C *)0);
#ifndef SUPPRESSED
- // expected-warning at ../Inputs/system-header-simulator-cxx.h:741 {{Called C++ object pointer is null}}
+ // expected-warning at ../Inputs/system-header-simulator-cxx.h:752 {{Called C++ object pointer is null}}
#endif
}
diff --git a/clang/test/Analysis/std-variant-checker.cpp b/clang/test/Analysis/std-variant-checker.cpp
new file mode 100644
index 000000000000000..1deac7be7c7b0d4
--- /dev/null
+++ b/clang/test/Analysis/std-variant-checker.cpp
@@ -0,0 +1,349 @@
+// RUN: %clang %s -std=c++17 -Xclang -verify --analyze \
+// RUN: -Xclang -analyzer-checker=core \
+// RUN: -Xclang -analyzer-checker=debug.ExprInspection \
+// RUN: -Xclang -analyzer-checker=core,alpha.core.StdVariant
+
+#include "Inputs/system-header-simulator-cxx.h"
+
+class Foo{};
+
+void clang_analyzer_warnIfReached();
+void clang_analyzer_eval(int);
+
+//helper functions
+void changeVariantType(std::variant<int, char> &v) {
+ v = 25;
+}
+
+void changesToInt(std::variant<int, char> &v);
+void changesToInt(std::variant<int, char> *v);
+
+void cannotChangePtr(const std::variant<int, char> &v);
+void cannotChangePtr(const std::variant<int, char> *v);
+
+char getUnknownChar();
+
+void swap(std::variant<int, char> &v1, std::variant<int, char> &v2) {
+ std::variant<int, char> tmp = v1;
+ v1 = v2;
+ v2 = tmp;
+}
+
+void cantDo(const std::variant<int, char>& v) {
+ std::variant<int, char> vtmp = v;
+ vtmp = 5;
+ int a = std::get<int> (vtmp);
+ (void*) a;
+}
+
+void changeVariantPtr(std::variant<int, char> *v) {
+ *v = 'c';
+}
+
+using var_t = std::variant<int, char>;
+using var_tt = var_t;
+using int_t = int;
+using char_t = char;
+
+
+//----------------------------------------------------------------------------//
+// std::get
+//----------------------------------------------------------------------------//
+void stdGetType() {
+ std::variant<int, char> v = 25;
+ int a = std::get<int>(v);
+ char c = std::get<char>(v); // expected-warning {{std::variant 'v' held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+}
+
+void stdGetPointer() {
+ int *p = new int;
+ std::variant<int*, char> v = p;
+ int *a = std::get<int*>(v);
+ char c = std::get<char>(v); // expected-warning {{std::variant 'v' held an 'int *' not a 'char'}}
+ (void**)a;
+ (void*)c;
+ delete p;
+}
+
+void stdGetObject() {
+ std::variant<int, char, Foo> v = Foo{};
+ Foo f = std::get<Foo>(v);
+ int i = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'Foo' not an 'int'}}
+ (void*)i;
+}
+
+void stdGetPointerAndPointee() {
+ int a = 5;
+ std::variant<int, int*> v = &a;
+ int *b = std::get<int*>(v);
+ int c = std::get<int>(v); // expected-warning {{std::variant 'v' held an 'int *' not an 'int'}}
+ (void*)c;
+ (void**)b;
+}
+
+void variantHoldingVariant() {
+ std::variant<std::variant<int, char>, std::variant<char, int>> v = std::variant<int,char>(25);
+ std::variant<int, char> v1 = std::get<std::variant<int,char>>(v);
+ std::variant<char, int> v2 = std::get<std::variant<char,int>>(v); // expected-warning {{std::variant 'v' held a 'std::variant<int, char>' not a 'class std::variant<char, int>'}}
+}
+
+//----------------------------------------------------------------------------//
+// Constructors and assignments
+//----------------------------------------------------------------------------//
+void copyConstructor() {
+ std::variant<int, char> v = 25;
+ std::variant<int, char> t(v);
+ int a = std::get<int> (t);
+ char c = std::get<char> (t); // expected-warning {{std::variant 't' held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+}
+
+void copyAssignmentOperator() {
+ std::variant<int, char> v = 25;
+ std::variant<int, char> t = 'c';
+ t = v;
+ int a = std::get<int> (t);
+ char c = std::get<char> (t); // expected-warning {{std::variant 't' held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+}
+
+void assignmentOperator() {
+ std::variant<int, char> v = 25;
+ int a = std::get<int> (v);
+ (void*)a;
+ v = 'c';
+ char c = std::get<char>(v);
+ a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+void typeChangeThreeTimes() {
+ std::variant<int, char, float> v = 25;
+ int a = std::get<int> (v);
+ (void*)a;
+ v = 'c';
+ char c = std::get<char>(v);
+ v = 25;
+ a = std::get<int>(v);
+ (void*)a;
+ v = 1.25f;
+ float f = std::get<float>(v);
+ a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'float' not an 'int'}}
+ (void*)a;
+ (void*)c;
+ f+0.f;
+}
+
+void defaultConstructor() {
+ std::variant<int, char> v;
+ int i = std::get<int>(v);
+ char c = std::get<char>(v); // expected-warning {{std::variant 'v' held an 'int' not a 'char'}}
+ (void*)i;
+ (void*)c;
+}
+
+// Verify that we handle temporary objects correctly
+void temporaryObjectsConstructor() {
+ std::variant<int, char> v(std::variant<int, char>('c'));
+ char c = std::get<char>(v);
+ int a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+void temporaryObjectsAssignment() {
+ std::variant<int, char> v = std::variant<int, char>('c');
+ char c = std::get<char>(v);
+ int a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+// Verify that we handle pointer types correctly
+void pointerTypeHeld() {
+ int *p = new int;
+ std::variant<int*, char> v = p;
+ int *a = std::get<int*>(v);
+ char c = std::get<char>(v); // expected-warning {{std::variant 'v' held an 'int *' not a 'char'}}
+ (void**)a;
+ (void*)c;
+ delete p;
+}
+
+std::variant<int, char> get_unknown_variant();
+// Verify that the copy constructor is handles properly when the std::variant
+// has no previously activated type and we copy an object of unknown value in it.
+void copyFromUnknownVariant() {
+ std::variant<int, char> u = get_unknown_variant();
+ std::variant<int, char> v(u);
+ int a = std::get<int>(v); // no-waring
+ char c = std::get<char>(v); // no-warning
+ (void*)a;
+ (void*)c;
+}
+
+// Verify that the copy constructor is handles properly when the std::variant
+// has previously activated type and we copy an object of unknown value in it.
+void copyFromUnknownVariantBef() {
+ std::variant<int, char> v = 25;
+ std::variant<int, char> u = get_unknown_variant();
+ v = u;
+ int a = std::get<int>(v); // no-waring
+ char c = std::get<char>(v); // no-warning
+ (void*)a;
+ (void*)c;
+}
+
+//----------------------------------------------------------------------------//
+// typedef
+//----------------------------------------------------------------------------//
+
+void typefdefedVariant() {
+ var_t v = 25;
+ int a = std::get<int>(v);
+ char c = std::get<char>(v); // expected-warning {{std::variant 'v' held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+}
+
+void typedefedTypedfefedVariant() {
+ var_tt v = 25;
+ int a = std::get<int>(v);
+ char c = std::get<char>(v); // expected-warning {{std::variant 'v' held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+}
+
+void typedefedGet() {
+ std::variant<char, int> v = 25;
+ int a = std::get<int_t>(v);
+ char c = std::get<char_t>(v); // expected-warning {{std::variant 'v' held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+}
+
+void typedefedPack() {
+ std::variant<int_t, char_t> v = 25;
+ int a = std::get<int>(v);
+ char c = std::get<char>(v); // expected-warning {{std::variant 'v' held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+}
+
+void fromVariable() {
+ char o = 'c';
+ std::variant<int, char> v(o);
+ char c = std::get<char>(v);
+ int a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+void unknowValueButKnownType() {
+ char o = getUnknownChar();
+ std::variant<int, char> v(o);
+ char c = std::get<char>(v);
+ int a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+void createPointer() {
+ std::variant<int, char> *v = new std::variant<int, char>(15);
+ int a = std::get<int>(*v);
+ char c = std::get<char>(*v); // expected-warning {{std::variant held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+ delete v;
+}
+
+//----------------------------------------------------------------------------//
+// Passing std::variants to functions
+//----------------------------------------------------------------------------//
+
+// Verifying that we are not invalidating the memory region of a variant if
+// a non inlined or inlined function takes it as a constant reference or po'int'er
+void constNonInlineRef() {
+ std::variant<int, char> v = 'c';
+ cannotChangePtr(v);
+ char c = std::get<char>(v);
+ int a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+void contNonInlinePtr() {
+ std::variant<int, char> v = 'c';
+ cannotChangePtr(&v);
+ char c = std::get<char>(v);
+ int a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+void copyInAFunction() {
+ std::variant<int, char> v = 'c';
+ cantDo(v);
+ char c = std::get<char>(v);
+ int a = std::get<int>(v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+
+}
+
+// Verifying that we can keep track of the type stored in std::variant when
+// it is passed to an inlined function as a reference or pointer
+void changeThruPointers() {
+ std::variant<int, char> v = 15;
+ changeVariantPtr(&v);
+ char c = std::get<char> (v);
+ int a = std::get<int> (v); // expected-warning {{std::variant 'v' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+void functionCallWithCopyAssignment() {
+ var_t v1 = 15;
+ var_t v2 = 'c';
+ swap(v1, v2);
+ int a = std::get<int> (v2);
+ (void*)a;
+ char c = std::get<char> (v1);
+ a = std::get<int> (v1); // expected-warning {{std::variant 'v1' held a 'char' not an 'int'}}
+ (void*)a;
+ (void*)c;
+}
+
+void inlineFunctionCall() {
+ std::variant<int, char> v = 'c';
+ changeVariantType(v);
+ int a = std::get<int> (v);
+ char c = std::get<char> (v); // expected-warning {{std::variant 'v' held an 'int' not a 'char'}}
+ (void*)a;
+ (void*)c;
+}
+
+// Verifying that we invalidate the mem region of std::variant when it is
+// passed as a non const reference or a po'int'er to a non inlined function.
+void nonInlineFunctionCall() {
+ std::variant<int, char> v = 'c';
+ changesToInt(v);
+ int a = std::get<int> (v); // no-waring
+ char c = std::get<char> (v); // no-warning
+ (void*)a;
+ (void*)c;
+}
+
+void nonInlineFunctionCallPtr() {
+ std::variant<int, char> v = 'c';
+ changesToInt(&v);
+ int a = std::get<int> (v); // no-warning
+ char c = std::get<char> (v); // no-warning
+ (void*)a;
+ (void*)c;
+}
\ No newline at end of file
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