[clang] 92a09c0 - [clang][nullability] allow _Nonnull etc on nullable class types (#82705)
via cfe-commits
cfe-commits at lists.llvm.org
Thu Mar 14 08:45:27 PDT 2024
Author: Sam McCall
Date: 2024-03-14T16:45:24+01:00
New Revision: 92a09c0165b87032e1bd05020a78ed845cf35661
URL: https://github.com/llvm/llvm-project/commit/92a09c0165b87032e1bd05020a78ed845cf35661
DIFF: https://github.com/llvm/llvm-project/commit/92a09c0165b87032e1bd05020a78ed845cf35661.diff
LOG: [clang][nullability] allow _Nonnull etc on nullable class types (#82705)
This enables clang and external nullability checkers to make use of
these annotations on nullable C++ class types like unique_ptr.
These types are recognized by the presence of the _Nullable attribute.
Nullable standard library types implicitly receive this attribute.
Existing static warnings for raw pointers are extended to smart
pointers:
- nullptr used as return value or argument for non-null functions
(`-Wnonnull`)
- assigning or initializing nonnull variables with nullable values
(`-Wnullable-to-nonnull-conversion`)
It doesn't implicitly add these attributes based on the assume_nonnull
pragma, nor warn on missing attributes where the pragma would apply
them.
I'm not confident that the pragma's current behavior will work well for
C++ (where type-based metaprogramming is much more common than C/ObjC).
We'd like to revisit this once we have more implementation experience.
Support can be detected as `__has_feature(nullability_on_classes)`.
This is needed for back-compatibility, as previously clang would issue a
hard error when _Nullable appears on a smart pointer.
UBSan's `-fsanitize=nullability` will not check smart-pointer types.
It can be made to do so by synthesizing calls to `operator bool`, but
that's left for future work.
Discussion:
https://discourse.llvm.org/t/rfc-allowing-nonnull-etc-on-smart-pointers/77201/26
Added:
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/Attr.td
clang/include/clang/Basic/AttrDocs.td
clang/include/clang/Basic/Features.def
clang/include/clang/Parse/Parser.h
clang/include/clang/Sema/Sema.h
clang/lib/AST/Type.cpp
clang/lib/CodeGen/CGCall.cpp
clang/lib/CodeGen/CodeGenFunction.cpp
clang/lib/Parse/ParseDeclCXX.cpp
clang/lib/Sema/SemaAttr.cpp
clang/lib/Sema/SemaChecking.cpp
clang/lib/Sema/SemaDecl.cpp
clang/lib/Sema/SemaDeclAttr.cpp
clang/lib/Sema/SemaInit.cpp
clang/lib/Sema/SemaOverload.cpp
clang/lib/Sema/SemaTemplate.cpp
clang/lib/Sema/SemaType.cpp
clang/test/Sema/nullability.c
clang/test/SemaCXX/nullability.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 71c1edc8f67b17..459f6a25aeef7b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -201,6 +201,21 @@ Attribute Changes in Clang
and each must be a positive integer when provided. The parameter ``x`` is required, while ``y`` and
``z`` are optional with default value of 1.
+- The ``_Nullable`` and ``_Nonnull`` family of type attributes can now apply
+ to certain C++ class types, such as smart pointers:
+ ``void useObject(std::unique_ptr<Object> _Nonnull obj);``.
+
+ This works for standard library types including ``unique_ptr``, ``shared_ptr``
+ and ``function``. See `the attribute reference
+documentation <https://llvm.org/docs/AttributeReference.html#nullability-attributes>`_
+for the full list.
+
+- The ``_Nullable`` attribute can be applied to C++ class declarations:
+ ``template <class T> class _Nullable MySmartPointer {};``.
+
+ This allows the ``_Nullable`` and ``_Nonnull` family of type attributes to
+ apply to this class.
+
Improvements to Clang's diagnostics
-----------------------------------
- Clang now applies syntax highlighting to the code snippets it
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 67d87eca16ede8..24bc06476b1f9c 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2178,9 +2178,10 @@ def TypeNonNull : TypeAttr {
let Documentation = [TypeNonNullDocs];
}
-def TypeNullable : TypeAttr {
+def TypeNullable : DeclOrTypeAttr {
let Spellings = [CustomKeyword<"_Nullable">];
let Documentation = [TypeNullableDocs];
+// let Subjects = SubjectList<[CXXRecord], ErrorDiag>;
}
def TypeNullableResult : TypeAttr {
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index d61f96ade557d5..075324a213ff78 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -4151,6 +4151,20 @@ non-underscored keywords. For example:
@property (assign, nullable) NSView *superview;
@property (readonly, nonnull) NSArray *subviews;
@end
+
+As well as built-in pointer types, the nullability attributes can be attached
+to C++ classes marked with the ``_Nullable`` attribute.
+
+The following C++ standard library types are considered nullable:
+``unique_ptr``, ``shared_ptr``, ``auto_ptr``, ``exception_ptr``, ``function``,
+``move_only_function`` and ``coroutine_handle``.
+
+Types should be marked nullable only where the type itself leaves nullability
+ambiguous. For example, ``std::optional`` is not marked ``_Nullable``, because
+``optional<int> _Nullable`` is redundant and ``optional<int> _Nonnull`` is
+not a useful type. ``std::weak_ptr`` is not nullable, because its nullability
+can change with no visible modification, so static annotation is unlikely to be
+unhelpful.
}];
}
@@ -4185,6 +4199,17 @@ The ``_Nullable`` nullability qualifier indicates that a value of the
int fetch_or_zero(int * _Nullable ptr);
a caller of ``fetch_or_zero`` can provide null.
+
+The ``_Nullable`` attribute on classes indicates that the given class can
+represent null values, and so the ``_Nullable``, ``_Nonnull`` etc qualifiers
+make sense for this type. For example:
+
+ .. code-block:: c
+
+ class _Nullable ArenaPointer { ... };
+
+ ArenaPointer _Nonnull x = ...;
+ ArenaPointer _Nullable y = nullptr;
}];
}
diff --git a/clang/include/clang/Basic/Features.def b/clang/include/clang/Basic/Features.def
index 5fad5fc3623cb6..7c0755b7318306 100644
--- a/clang/include/clang/Basic/Features.def
+++ b/clang/include/clang/Basic/Features.def
@@ -94,6 +94,7 @@ EXTENSION(define_target_os_macros,
FEATURE(enumerator_attributes, true)
FEATURE(nullability, true)
FEATURE(nullability_on_arrays, true)
+FEATURE(nullability_on_classes, true)
FEATURE(nullability_nullable_result, true)
FEATURE(memory_sanitizer,
LangOpts.Sanitize.hasOneOf(SanitizerKind::Memory |
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 64e031d5094c74..14df75180ef321 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -3014,6 +3014,7 @@ class Parser : public CodeCompletionHandler {
void DiagnoseAndSkipExtendedMicrosoftTypeAttributes();
SourceLocation SkipExtendedMicrosoftTypeAttributes();
void ParseMicrosoftInheritanceClassAttributes(ParsedAttributes &attrs);
+ void ParseNullabilityClassAttributes(ParsedAttributes &attrs);
void ParseBorlandTypeAttributes(ParsedAttributes &attrs);
void ParseOpenCLKernelAttributes(ParsedAttributes &attrs);
void ParseOpenCLQualifiers(ParsedAttributes &Attrs);
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 69d5709e5e2f06..64de39acc72176 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -1655,6 +1655,9 @@ class Sema final {
/// Add [[gsl::Pointer]] attributes for std:: types.
void inferGslPointerAttribute(TypedefNameDecl *TD);
+ /// Add _Nullable attributes for std:: types.
+ void inferNullableClassAttribute(CXXRecordDecl *CRD);
+
enum PragmaOptionsAlignKind {
POAK_Native, // #pragma options align=native
POAK_Natural, // #pragma options align=natural
diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index 22666184c56ccf..f7730bc776b373 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -4558,16 +4558,15 @@ bool Type::canHaveNullability(bool ResultIfUnknown) const {
case Type::Auto:
return ResultIfUnknown;
- // Dependent template specializations can instantiate to pointer
- // types unless they're known to be specializations of a class
- // template.
+ // Dependent template specializations could instantiate to pointer types.
case Type::TemplateSpecialization:
- if (TemplateDecl *templateDecl
- = cast<TemplateSpecializationType>(type.getTypePtr())
- ->getTemplateName().getAsTemplateDecl()) {
- if (isa<ClassTemplateDecl>(templateDecl))
- return false;
- }
+ // If it's a known class template, we can already check if it's nullable.
+ if (TemplateDecl *templateDecl =
+ cast<TemplateSpecializationType>(type.getTypePtr())
+ ->getTemplateName()
+ .getAsTemplateDecl())
+ if (auto *CTD = dyn_cast<ClassTemplateDecl>(templateDecl))
+ return CTD->getTemplatedDecl()->hasAttr<TypeNullableAttr>();
return ResultIfUnknown;
case Type::Builtin:
@@ -4624,6 +4623,17 @@ bool Type::canHaveNullability(bool ResultIfUnknown) const {
}
llvm_unreachable("unknown builtin type");
+ case Type::Record: {
+ const RecordDecl *RD = cast<RecordType>(type)->getDecl();
+ // For template specializations, look only at primary template attributes.
+ // This is a consistent regardless of whether the instantiation is known.
+ if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(RD))
+ return CTSD->getSpecializedTemplate()
+ ->getTemplatedDecl()
+ ->hasAttr<TypeNullableAttr>();
+ return RD->hasAttr<TypeNullableAttr>();
+ }
+
// Non-pointer types.
case Type::Complex:
case Type::LValueReference:
@@ -4641,7 +4651,6 @@ bool Type::canHaveNullability(bool ResultIfUnknown) const {
case Type::DependentAddressSpace:
case Type::FunctionProto:
case Type::FunctionNoProto:
- case Type::Record:
case Type::DeducedTemplateSpecialization:
case Type::Enum:
case Type::InjectedClassName:
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index a28d7888715d85..17607fe500413d 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -4372,7 +4372,8 @@ void CodeGenFunction::EmitNonNullArgCheck(RValue RV, QualType ArgType,
NNAttr = getNonNullAttr(AC.getDecl(), PVD, ArgType, ArgNo);
bool CanCheckNullability = false;
- if (SanOpts.has(SanitizerKind::NullabilityArg) && !NNAttr && PVD) {
+ if (SanOpts.has(SanitizerKind::NullabilityArg) && !NNAttr && PVD &&
+ !PVD->getType()->isRecordType()) {
auto Nullability = PVD->getType()->getNullability();
CanCheckNullability = Nullability &&
*Nullability == NullabilityKind::NonNull &&
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 4a3ff49b0007a3..8e4dc8915602fa 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -979,7 +979,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
// return value. Initialize the flag to 'true' and refine it in EmitParmDecl.
if (SanOpts.has(SanitizerKind::NullabilityReturn)) {
auto Nullability = FnRetTy->getNullability();
- if (Nullability && *Nullability == NullabilityKind::NonNull) {
+ if (Nullability && *Nullability == NullabilityKind::NonNull &&
+ !FnRetTy->isRecordType()) {
if (!(SanOpts.has(SanitizerKind::ReturnsNonnullAttribute) &&
CurCodeDecl && CurCodeDecl->getAttr<ReturnsNonNullAttr>()))
RetValNullabilityPrecondition =
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 77d2382ea6d907..b23f9ba1bfd460 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -1494,6 +1494,15 @@ void Parser::ParseMicrosoftInheritanceClassAttributes(ParsedAttributes &attrs) {
}
}
+void Parser::ParseNullabilityClassAttributes(ParsedAttributes &attrs) {
+ while (Tok.is(tok::kw__Nullable)) {
+ IdentifierInfo *AttrName = Tok.getIdentifierInfo();
+ auto Kind = Tok.getKind();
+ SourceLocation AttrNameLoc = ConsumeToken();
+ attrs.addNew(AttrName, AttrNameLoc, nullptr, AttrNameLoc, nullptr, 0, Kind);
+ }
+}
+
/// Determine whether the following tokens are valid after a type-specifier
/// which could be a standalone declaration. This will conservatively return
/// true if there's any doubt, and is appropriate for insert-';' fixits.
@@ -1675,15 +1684,21 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
ParsedAttributes attrs(AttrFactory);
// If attributes exist after tag, parse them.
- MaybeParseAttributes(PAKM_CXX11 | PAKM_Declspec | PAKM_GNU, attrs);
-
- // Parse inheritance specifiers.
- if (Tok.isOneOf(tok::kw___single_inheritance, tok::kw___multiple_inheritance,
- tok::kw___virtual_inheritance))
- ParseMicrosoftInheritanceClassAttributes(attrs);
-
- // Allow attributes to precede or succeed the inheritance specifiers.
- MaybeParseAttributes(PAKM_CXX11 | PAKM_Declspec | PAKM_GNU, attrs);
+ for (;;) {
+ MaybeParseAttributes(PAKM_CXX11 | PAKM_Declspec | PAKM_GNU, attrs);
+ // Parse inheritance specifiers.
+ if (Tok.isOneOf(tok::kw___single_inheritance,
+ tok::kw___multiple_inheritance,
+ tok::kw___virtual_inheritance)) {
+ ParseMicrosoftInheritanceClassAttributes(attrs);
+ continue;
+ }
+ if (Tok.is(tok::kw__Nullable)) {
+ ParseNullabilityClassAttributes(attrs);
+ continue;
+ }
+ break;
+ }
// Source location used by FIXIT to insert misplaced
// C++11 attributes
diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 0dcf42e4899713..a5dd158808f26b 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -215,6 +215,18 @@ void Sema::inferGslOwnerPointerAttribute(CXXRecordDecl *Record) {
inferGslPointerAttribute(Record, Record);
}
+void Sema::inferNullableClassAttribute(CXXRecordDecl *CRD) {
+ static llvm::StringSet<> Nullable{
+ "auto_ptr", "shared_ptr", "unique_ptr", "exception_ptr",
+ "coroutine_handle", "function", "move_only_function",
+ };
+
+ if (CRD->isInStdNamespace() && Nullable.count(CRD->getName()) &&
+ !CRD->hasAttr<TypeNullableAttr>())
+ for (Decl *Redecl : CRD->redecls())
+ Redecl->addAttr(TypeNullableAttr::CreateImplicit(Context));
+}
+
void Sema::ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
SourceLocation PragmaLoc) {
PragmaMsStackAction Action = Sema::PSK_Reset;
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index a5f42b630c3fa2..124fb2b65438b5 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -27,6 +27,7 @@
#include "clang/AST/ExprObjC.h"
#include "clang/AST/ExprOpenMP.h"
#include "clang/AST/FormatString.h"
+#include "clang/AST/IgnoreExpr.h"
#include "clang/AST/NSAPI.h"
#include "clang/AST/NonTrivialTypeVisitor.h"
#include "clang/AST/OperationKinds.h"
@@ -7316,6 +7317,14 @@ bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
///
/// Returns true if the value evaluates to null.
static bool CheckNonNullExpr(Sema &S, const Expr *Expr) {
+ // Treat (smart) pointers constructed from nullptr as null, whether we can
+ // const-evaluate them or not.
+ // This must happen first: the smart pointer expr might have _Nonnull type!
+ if (isa<CXXNullPtrLiteralExpr>(
+ IgnoreExprNodes(Expr, IgnoreImplicitAsWrittenSingleStep,
+ IgnoreElidableImplicitConstructorSingleStep)))
+ return true;
+
// If the expression has non-null type, it doesn't evaluate to null.
if (auto nullability = Expr->IgnoreImplicit()->getType()->getNullability()) {
if (*nullability == NullabilityKind::NonNull)
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 5850cd0ab6b9aa..7acce77458a372 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -18254,8 +18254,10 @@ Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
if (PrevDecl)
mergeDeclAttributes(New, PrevDecl);
- if (auto *CXXRD = dyn_cast<CXXRecordDecl>(New))
+ if (auto *CXXRD = dyn_cast<CXXRecordDecl>(New)) {
inferGslOwnerPointerAttribute(CXXRD);
+ inferNullableClassAttribute(CXXRD);
+ }
// If there's a #pragma GCC visibility in scope, set the visibility of this
// record.
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index ec00fdf3f88d9e..47e1d9debac3f4 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5976,6 +5976,20 @@ static void handleBuiltinAliasAttr(Sema &S, Decl *D,
D->addAttr(::new (S.Context) BuiltinAliasAttr(S.Context, AL, Ident));
}
+static void handleNullableTypeAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+ if (AL.isUsedAsTypeAttr())
+ return;
+
+ if (auto *CRD = dyn_cast<CXXRecordDecl>(D);
+ !CRD || !(CRD->isClass() || CRD->isStruct())) {
+ S.Diag(AL.getRange().getBegin(), diag::err_attribute_wrong_decl_type_str)
+ << AL << AL.isRegularKeywordAttribute() << "classes";
+ return;
+ }
+
+ handleSimpleAttribute<TypeNullableAttr>(S, D, AL);
+}
+
static void handlePreferredTypeAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
if (!AL.hasParsedType()) {
S.Diag(AL.getLoc(), diag::err_attribute_wrong_number_arguments) << AL << 1;
@@ -9945,6 +9959,10 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
case ParsedAttr::AT_UsingIfExists:
handleSimpleAttribute<UsingIfExistsAttr>(S, D, AL);
break;
+
+ case ParsedAttr::AT_TypeNullable:
+ handleNullableTypeAttr(S, D, AL);
+ break;
}
}
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index aa470adb30b47f..96029072257d1c 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -7075,6 +7075,11 @@ PerformConstructorInitialization(Sema &S,
hasCopyOrMoveCtorParam(S.Context,
getConstructorInfo(Step.Function.FoundDecl));
+ // A smart pointer constructed from a nullable pointer is nullable.
+ if (NumArgs == 1 && !Kind.isExplicitCast())
+ S.diagnoseNullableToNonnullConversion(
+ Entity.getType(), Args.front()->getType(), Kind.getLocation());
+
// Determine the arguments required to actually perform the constructor
// call.
if (S.CompleteConstructorCall(Constructor, Step.Type, Args, Loc,
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index f6bd85bdc64692..4e03c3124e39ab 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -14797,6 +14797,13 @@ ExprResult Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
}
}
+ // Check for nonnull = nullable.
+ // This won't be caught in the arg's initialization: the parameter to
+ // the assignment operator is not marked nonnull.
+ if (Op == OO_Equal)
+ diagnoseNullableToNonnullConversion(Args[0]->getType(),
+ Args[1]->getType(), OpLoc);
+
// Convert the arguments.
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
// Best->Access is only meaningful for class members.
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 005529a53270c3..8bc7f5f3607338 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -2171,6 +2171,7 @@ DeclResult Sema::CheckClassTemplate(
AddPushedVisibilityAttribute(NewClass);
inferGslOwnerPointerAttribute(NewClass);
+ inferNullableClassAttribute(NewClass);
if (TUK != TUK_Friend) {
// Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 9aaacaa0771f2f..81d69fff24f4e7 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -4711,6 +4711,18 @@ static bool DiagnoseMultipleAddrSpaceAttributes(Sema &S, LangAS ASOld,
return false;
}
+// Whether this is a type broadly expected to have nullability attached.
+// These types are affected by `#pragma assume_nonnull`, and missing nullability
+// will be diagnosed with -Wnullability-completeness.
+static bool shouldHaveNullability(QualType T) {
+ return T->canHaveNullability(/*ResultIfUnknown=*/false) &&
+ // For now, do not infer/require nullability on C++ smart pointers.
+ // It's unclear whether the pragma's behavior is useful for C++.
+ // e.g. treating type-aliases and template-type-parameters
diff erently
+ // from types of declarations can be surprising.
+ !isa<RecordType>(T);
+}
+
static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
QualType declSpecType,
TypeSourceInfo *TInfo) {
@@ -4829,8 +4841,7 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
// inner pointers.
complainAboutMissingNullability = CAMN_InnerPointers;
- if (T->canHaveNullability(/*ResultIfUnknown*/ false) &&
- !T->getNullability()) {
+ if (shouldHaveNullability(T) && !T->getNullability()) {
// Note that we allow but don't require nullability on dependent types.
++NumPointersRemaining;
}
@@ -5053,8 +5064,7 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
// If the type itself could have nullability but does not, infer pointer
// nullability and perform consistency checking.
if (S.CodeSynthesisContexts.empty()) {
- if (T->canHaveNullability(/*ResultIfUnknown*/ false) &&
- !T->getNullability()) {
+ if (shouldHaveNullability(T) && !T->getNullability()) {
if (isVaList(T)) {
// Record that we've seen a pointer, but do nothing else.
if (NumPointersRemaining > 0)
diff --git a/clang/test/Sema/nullability.c b/clang/test/Sema/nullability.c
index 7d193bea46771f..0401516233b6db 100644
--- a/clang/test/Sema/nullability.c
+++ b/clang/test/Sema/nullability.c
@@ -248,3 +248,5 @@ void arraysInBlocks(void) {
void (^withTypedefBad)(INTS _Nonnull [2]) = // expected-error {{nullability specifier '_Nonnull' cannot be applied to non-pointer type 'INTS' (aka 'int[4]')}}
^(INTS _Nonnull x[2]) {}; // expected-error {{nullability specifier '_Nonnull' cannot be applied to non-pointer type 'INTS' (aka 'int[4]')}}
}
+
+struct _Nullable NotCplusplusClass {}; // expected-error {{'_Nullable' attribute only applies to classes}}
diff --git a/clang/test/SemaCXX/nullability.cpp b/clang/test/SemaCXX/nullability.cpp
index 8d0c4dc195a6bd..d52ba4efaccdbd 100644
--- a/clang/test/SemaCXX/nullability.cpp
+++ b/clang/test/SemaCXX/nullability.cpp
@@ -4,6 +4,10 @@
#else
# error nullability feature should be defined
#endif
+#if __has_feature(nullability_on_classes)
+#else
+# error smart-pointer feature should be defined
+#endif
#include "nullability-completeness.h"
@@ -27,6 +31,7 @@ template<typename T>
struct AddNonNull {
typedef _Nonnull T type; // expected-error{{nullability specifier '_Nonnull' cannot be applied to non-pointer type 'int'}}
// expected-error at -1{{nullability specifier '_Nonnull' cannot be applied to non-pointer type 'std::nullptr_t'}}
+ // expected-error at -2{{nullability specifier '_Nonnull' cannot be applied to non-pointer type 'NotPtr'}}
};
typedef AddNonNull<int *>::type nonnull_int_ptr_1;
@@ -35,6 +40,33 @@ typedef AddNonNull<nullptr_t>::type nonnull_int_ptr_3; // expected-note{{in inst
typedef AddNonNull<int>::type nonnull_non_pointer_1; // expected-note{{in instantiation of template class 'AddNonNull<int>' requested here}}
+// Nullability on C++ class types (smart pointers).
+struct NotPtr{};
+typedef AddNonNull<NotPtr>::type nonnull_non_pointer_2; // expected-note{{in instantiation}}
+struct _Nullable SmartPtr{
+ SmartPtr();
+ SmartPtr(nullptr_t);
+ SmartPtr(const SmartPtr&);
+ SmartPtr(SmartPtr&&);
+ SmartPtr &operator=(const SmartPtr&);
+ SmartPtr &operator=(SmartPtr&&);
+};
+typedef AddNonNull<SmartPtr>::type nonnull_smart_pointer_1;
+template<class> struct _Nullable SmartPtrTemplate{};
+typedef AddNonNull<SmartPtrTemplate<int>>::type nonnull_smart_pointer_2;
+namespace std { inline namespace __1 {
+ template <class> class unique_ptr {};
+ template <class> class function;
+ template <class Ret, class... Args> class function<Ret(Args...)> {};
+} }
+typedef AddNonNull<std::unique_ptr<int>>::type nonnull_smart_pointer_3;
+typedef AddNonNull<std::function<int()>>::type nonnull_smart_pointer_4;
+
+class Derived : public SmartPtr {};
+Derived _Nullable x; // expected-error {{'_Nullable' cannot be applied}}
+class DerivedPrivate : private SmartPtr {};
+DerivedPrivate _Nullable y; // expected-error {{'_Nullable' cannot be applied}}
+
// Non-null checking within a template.
template<typename T>
struct AddNonNull2 {
@@ -54,6 +86,7 @@ void (*& accepts_nonnull_2)(_Nonnull int *ptr) = accepts_nonnull_1;
void (X::* accepts_nonnull_3)(_Nonnull int *ptr);
void accepts_nonnull_4(_Nonnull int *ptr);
void (&accepts_nonnull_5)(_Nonnull int *ptr) = accepts_nonnull_4;
+void accepts_nonnull_6(SmartPtr _Nonnull);
void test_accepts_nonnull_null_pointer_literal(X *x) {
accepts_nonnull_1(0); // expected-warning{{null passed to a callee that requires a non-null argument}}
@@ -61,6 +94,8 @@ void test_accepts_nonnull_null_pointer_literal(X *x) {
(x->*accepts_nonnull_3)(0); // expected-warning{{null passed to a callee that requires a non-null argument}}
accepts_nonnull_4(0); // expected-warning{{null passed to a callee that requires a non-null argument}}
accepts_nonnull_5(0); // expected-warning{{null passed to a callee that requires a non-null argument}}
+
+ accepts_nonnull_6(nullptr); // expected-warning{{null passed to a callee that requires a non-null argument}}
}
template<void FP(_Nonnull int*)>
@@ -71,6 +106,7 @@ void test_accepts_nonnull_null_pointer_literal_template() {
template void test_accepts_nonnull_null_pointer_literal_template<&accepts_nonnull_4>(); // expected-note{{instantiation of function template specialization}}
void TakeNonnull(void *_Nonnull);
+void TakeSmartNonnull(SmartPtr _Nonnull);
// Check
diff erent forms of assignment to a nonull type from a nullable one.
void AssignAndInitNonNull() {
void *_Nullable nullable;
@@ -81,12 +117,26 @@ void AssignAndInitNonNull() {
void *_Nonnull nonnull;
nonnull = nullable; // expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull'}}
nonnull = {nullable}; // expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull'}}
-
TakeNonnull(nullable); //expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull}}
TakeNonnull(nonnull); // OK
+ nonnull = (void *_Nonnull)nullable; // explicit cast OK
+
+ SmartPtr _Nullable s_nullable;
+ SmartPtr _Nonnull s(s_nullable); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ SmartPtr _Nonnull s2{s_nullable}; // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ SmartPtr _Nonnull s3 = {s_nullable}; // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ SmartPtr _Nonnull s4 = s_nullable; // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ SmartPtr _Nonnull s_nonnull;
+ s_nonnull = s_nullable; // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ s_nonnull = {s_nullable}; // no warning here - might be nice?
+ TakeSmartNonnull(s_nullable); //expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull}}
+ TakeSmartNonnull(s_nonnull); // OK
+ s_nonnull = (SmartPtr _Nonnull)s_nullable; // explicit cast OK
+ s_nonnull = static_cast<SmartPtr _Nonnull>(s_nullable); // explicit cast OK
}
void *_Nullable ReturnNullable();
+SmartPtr _Nullable ReturnSmartNullable();
void AssignAndInitNonNullFromFn() {
void *_Nonnull p(ReturnNullable()); // expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull'}}
@@ -96,8 +146,16 @@ void AssignAndInitNonNullFromFn() {
void *_Nonnull nonnull;
nonnull = ReturnNullable(); // expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull'}}
nonnull = {ReturnNullable()}; // expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull'}}
-
TakeNonnull(ReturnNullable()); //expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull}}
+
+ SmartPtr _Nonnull s(ReturnSmartNullable()); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ SmartPtr _Nonnull s2{ReturnSmartNullable()}; // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ SmartPtr _Nonnull s3 = {ReturnSmartNullable()}; // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ SmartPtr _Nonnull s4 = ReturnSmartNullable(); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ SmartPtr _Nonnull s_nonnull;
+ s_nonnull = ReturnSmartNullable(); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+ s_nonnull = {ReturnSmartNullable()};
+ TakeSmartNonnull(ReturnSmartNullable()); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
}
void ConditionalExpr(bool c) {
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