[clang] 740a164 - PR46377: Fix dependence calculation for function types and typedef

Richard Smith via cfe-commits cfe-commits at lists.llvm.org
Fri Jul 31 17:20:42 PDT 2020


Thanks, was just an overzealous assertion. Should be fixed in
llvmorg-12-init-1765-g234f51a65a4.

On Fri, 31 Jul 2020 at 16:23, Nico Weber <thakis at chromium.org> wrote:

> Sorry, the repro link should've pointed to
> https://bugs.chromium.org/p/chromium/issues/detail?id=1110981#c22 which
> has a nicer stack.
>
> On Fri, Jul 31, 2020 at 7:22 PM Nico Weber <thakis at chromium.org> wrote:
>
>> Heads-up: This causes Chromium's build to fail with
>>
>> clang-cl:
>> /usr/local/google/home/thakis/src/chrome/src/third_party/llvm/clang/lib/AST/ASTContext.cpp:4823:
>> clang::QualType clang::ASTContext::getPackExpansionType(clang::QualType,
>> llvm::Optional<unsigned int>, bool): Assertion `(!ExpectPackInType ||
>> Pattern->containsUnexpandedParameterPack()) && "Pack expansions must expand
>> one or more parameter packs"' failed.
>>
>> under certain scenarios with precompiled headers. At the moment I only
>> have a repro when we use a Chromium-specific compiler plugin (
>> https://bugs.chromium.org/p/chromium/issues/detail?id=1110981#c19), but
>> it's likely I'll have one without that soonish.
>>
>> On Tue, Jul 28, 2020 at 4:23 PM Richard Smith via cfe-commits <
>> cfe-commits at lists.llvm.org> wrote:
>>
>>>
>>> Author: Richard Smith
>>> Date: 2020-07-28T13:23:13-07:00
>>> New Revision: 740a164dec483225cbd02ab6c82199e2747ffacb
>>>
>>> URL:
>>> https://github.com/llvm/llvm-project/commit/740a164dec483225cbd02ab6c82199e2747ffacb
>>> DIFF:
>>> https://github.com/llvm/llvm-project/commit/740a164dec483225cbd02ab6c82199e2747ffacb.diff
>>>
>>> LOG: PR46377: Fix dependence calculation for function types and typedef
>>> types.
>>>
>>> We previously did not treat a function type as dependent if it had a
>>> parameter pack with a non-dependent type -- such a function type depends
>>> on the arity of the pack so is dependent even though none of the
>>> parameter types is dependent. In order to properly handle this, we now
>>> treat pack expansion types as always being dependent types (depending on
>>> at least the pack arity), and always canonically being pack expansion
>>> types, even in the unusual case when the pattern is not a dependent
>>> type. This does mean that we can have canonical types that are pack
>>> expansions that contain no unexpanded packs, which is unfortunate but
>>> not inaccurate.
>>>
>>> We also previously did not treat a typedef type as
>>> instantiation-dependent if its canonical type was not
>>> instantiation-dependent. That's wrong because instantiation-dependence
>>> is a property of the type sugar, not of the type; an
>>> instantiation-dependent type can have a non-instantiation-dependent
>>> canonical type.
>>>
>>> Added:
>>>     clang/test/SemaTemplate/alias-template-nondependent.cpp
>>>
>>> Modified:
>>>     clang/include/clang/AST/ASTContext.h
>>>     clang/include/clang/AST/Type.h
>>>     clang/include/clang/Basic/TypeNodes.td
>>>     clang/lib/AST/ASTContext.cpp
>>>     clang/lib/AST/Type.cpp
>>>     clang/lib/CodeGen/CGDebugInfo.cpp
>>>     clang/lib/CodeGen/CodeGenFunction.cpp
>>>     clang/lib/Sema/SemaExpr.cpp
>>>     clang/lib/Sema/SemaLambda.cpp
>>>     clang/lib/Sema/SemaTemplateVariadic.cpp
>>>     clang/lib/Sema/SemaType.cpp
>>>
>>> Removed:
>>>
>>>
>>>
>>>
>>> ################################################################################
>>> diff  --git a/clang/include/clang/AST/ASTContext.h
>>> b/clang/include/clang/AST/ASTContext.h
>>> index 59e2679ddded..6c00fe86f282 100644
>>> --- a/clang/include/clang/AST/ASTContext.h
>>> +++ b/clang/include/clang/AST/ASTContext.h
>>> @@ -1459,8 +1459,16 @@ class ASTContext : public
>>> RefCountedBase<ASTContext> {
>>>    void getInjectedTemplateArgs(const TemplateParameterList *Params,
>>>                                 SmallVectorImpl<TemplateArgument> &Args);
>>>
>>> +  /// Form a pack expansion type with the given pattern.
>>> +  /// \param NumExpansions The number of expansions for the pack, if
>>> known.
>>> +  /// \param ExpectPackInType If \c false, we should not expect \p
>>> Pattern to
>>> +  ///        contain an unexpanded pack. This only makes sense if the
>>> pack
>>> +  ///        expansion is used in a context where the arity is inferred
>>> from
>>> +  ///        elsewhere, such as if the pattern contains a placeholder
>>> type or
>>> +  ///        if this is the canonical type of another pack expansion
>>> type.
>>>    QualType getPackExpansionType(QualType Pattern,
>>> -                                Optional<unsigned> NumExpansions);
>>> +                                Optional<unsigned> NumExpansions,
>>> +                                bool ExpectPackInType = true);
>>>
>>>    QualType getObjCInterfaceType(const ObjCInterfaceDecl *Decl,
>>>                                  ObjCInterfaceDecl *PrevDecl = nullptr)
>>> const;
>>>
>>> diff  --git a/clang/include/clang/AST/Type.h
>>> b/clang/include/clang/AST/Type.h
>>> index 9a745ef20fac..7fe652492b0e 100644
>>> --- a/clang/include/clang/AST/Type.h
>>> +++ b/clang/include/clang/AST/Type.h
>>> @@ -4383,11 +4383,7 @@ class TypedefType : public Type {
>>>  protected:
>>>    friend class ASTContext; // ASTContext creates these.
>>>
>>> -  TypedefType(TypeClass tc, const TypedefNameDecl *D, QualType can)
>>> -      : Type(tc, can, can->getDependence() &
>>> ~TypeDependence::UnexpandedPack),
>>> -        Decl(const_cast<TypedefNameDecl *>(D)) {
>>> -    assert(!isa<TypedefType>(can) && "Invalid canonical type");
>>> -  }
>>> +  TypedefType(TypeClass tc, const TypedefNameDecl *D, QualType can);
>>>
>>>  public:
>>>    TypedefNameDecl *getDecl() const { return Decl; }
>>> @@ -5624,7 +5620,8 @@ class PackExpansionType : public Type, public
>>> llvm::FoldingSetNode {
>>>    PackExpansionType(QualType Pattern, QualType Canon,
>>>                      Optional<unsigned> NumExpansions)
>>>        : Type(PackExpansion, Canon,
>>> -             (Pattern->getDependence() | TypeDependence::Instantiation)
>>> &
>>> +             (Pattern->getDependence() | TypeDependence::Dependent |
>>> +              TypeDependence::Instantiation) &
>>>                   ~TypeDependence::UnexpandedPack),
>>>          Pattern(Pattern) {
>>>      PackExpansionTypeBits.NumExpansions =
>>> @@ -5645,8 +5642,8 @@ class PackExpansionType : public Type, public
>>> llvm::FoldingSetNode {
>>>      return None;
>>>    }
>>>
>>> -  bool isSugared() const { return !Pattern->isDependentType(); }
>>> -  QualType desugar() const { return isSugared() ? Pattern :
>>> QualType(this, 0); }
>>> +  bool isSugared() const { return false; }
>>> +  QualType desugar() const { return QualType(this, 0); }
>>>
>>>    void Profile(llvm::FoldingSetNodeID &ID) {
>>>      Profile(ID, getPattern(), getNumExpansions());
>>>
>>> diff  --git a/clang/include/clang/Basic/TypeNodes.td
>>> b/clang/include/clang/Basic/TypeNodes.td
>>> index a4e3002b9075..011394c3ef45 100644
>>> --- a/clang/include/clang/Basic/TypeNodes.td
>>> +++ b/clang/include/clang/Basic/TypeNodes.td
>>> @@ -100,7 +100,7 @@ def DeducedTemplateSpecializationType :
>>> TypeNode<DeducedType>;
>>>  def InjectedClassNameType : TypeNode<Type>, AlwaysDependent, LeafType;
>>>  def DependentNameType : TypeNode<Type>, AlwaysDependent;
>>>  def DependentTemplateSpecializationType : TypeNode<Type>,
>>> AlwaysDependent;
>>> -def PackExpansionType : TypeNode<Type>, NeverCanonicalUnlessDependent;
>>> +def PackExpansionType : TypeNode<Type>, AlwaysDependent;
>>>  def ObjCTypeParamType : TypeNode<Type>, NeverCanonical;
>>>  def ObjCObjectType : TypeNode<Type>;
>>>  def ObjCInterfaceType : TypeNode<ObjCObjectType>, LeafType;
>>>
>>> diff  --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
>>> index e7518a538fe6..25bf71519d1c 100644
>>> --- a/clang/lib/AST/ASTContext.cpp
>>> +++ b/clang/lib/AST/ASTContext.cpp
>>> @@ -4817,37 +4817,27 @@ ASTContext::getInjectedTemplateArgs(const
>>> TemplateParameterList *Params,
>>>  }
>>>
>>>  QualType ASTContext::getPackExpansionType(QualType Pattern,
>>> -                                          Optional<unsigned>
>>> NumExpansions) {
>>> +                                          Optional<unsigned>
>>> NumExpansions,
>>> +                                          bool ExpectPackInType) {
>>> +  assert((!ExpectPackInType ||
>>> Pattern->containsUnexpandedParameterPack()) &&
>>> +         "Pack expansions must expand one or more parameter packs");
>>> +
>>>    llvm::FoldingSetNodeID ID;
>>>    PackExpansionType::Profile(ID, Pattern, NumExpansions);
>>>
>>> -  // A deduced type can deduce to a pack, eg
>>> -  //   auto ...x = some_pack;
>>> -  // That declaration isn't (yet) valid, but is created as part of
>>> building an
>>> -  // init-capture pack:
>>> -  //   [...x = some_pack] {}
>>> -  assert((Pattern->containsUnexpandedParameterPack() ||
>>> -          Pattern->getContainedDeducedType()) &&
>>> -         "Pack expansions must expand one or more parameter packs");
>>>    void *InsertPos = nullptr;
>>> -  PackExpansionType *T
>>> -    = PackExpansionTypes.FindNodeOrInsertPos(ID, InsertPos);
>>> +  PackExpansionType *T = PackExpansionTypes.FindNodeOrInsertPos(ID,
>>> InsertPos);
>>>    if (T)
>>>      return QualType(T, 0);
>>>
>>>    QualType Canon;
>>>    if (!Pattern.isCanonical()) {
>>> -    Canon = getCanonicalType(Pattern);
>>> -    // The canonical type might not contain an unexpanded parameter
>>> pack, if it
>>> -    // contains an alias template specialization which ignores one of
>>> its
>>> -    // parameters.
>>> -    if (Canon->containsUnexpandedParameterPack()) {
>>> -      Canon = getPackExpansionType(Canon, NumExpansions);
>>> -
>>> -      // Find the insert position again, in case we inserted an element
>>> into
>>> -      // PackExpansionTypes and invalidated our insert position.
>>> -      PackExpansionTypes.FindNodeOrInsertPos(ID, InsertPos);
>>> -    }
>>> +    Canon = getPackExpansionType(getCanonicalType(Pattern),
>>> NumExpansions,
>>> +                                 /*ExpectPackInType=*/false);
>>> +
>>> +    // Find the insert position again, in case we inserted an element
>>> into
>>> +    // PackExpansionTypes and invalidated our insert position.
>>> +    PackExpansionTypes.FindNodeOrInsertPos(ID, InsertPos);
>>>    }
>>>
>>>    T = new (*this, TypeAlignment)
>>>
>>> diff  --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
>>> index 0122d2e7de52..d40ba4c648c4 100644
>>> --- a/clang/lib/AST/Type.cpp
>>> +++ b/clang/lib/AST/Type.cpp
>>> @@ -1187,9 +1187,6 @@ struct SimpleTransformVisitor : public
>>> TypeVisitor<Derived, QualType> {
>>>                             T->getTypeConstraintArguments());
>>>    }
>>>
>>> -  // FIXME: Non-trivial to implement, but important for C++
>>> -  SUGARED_TYPE_CLASS(PackExpansion)
>>> -
>>>    QualType VisitObjCObjectType(const ObjCObjectType *T) {
>>>      QualType baseType = recurse(T->getBaseType());
>>>      if (baseType.isNull())
>>> @@ -3348,6 +3345,12 @@ void
>>> FunctionProtoType::Profile(llvm::FoldingSetNodeID &ID,
>>>            getExtProtoInfo(), Ctx, isCanonicalUnqualified());
>>>  }
>>>
>>> +TypedefType::TypedefType(TypeClass tc, const TypedefNameDecl *D,
>>> QualType can)
>>> +    : Type(tc, can, D->getUnderlyingType()->getDependence()),
>>> +      Decl(const_cast<TypedefNameDecl *>(D)) {
>>> +  assert(!isa<TypedefType>(can) && "Invalid canonical type");
>>> +}
>>> +
>>>  QualType TypedefType::desugar() const {
>>>    return getDecl()->getUnderlyingType();
>>>  }
>>>
>>> diff  --git a/clang/lib/CodeGen/CGDebugInfo.cpp
>>> b/clang/lib/CodeGen/CGDebugInfo.cpp
>>> index 6965c4a1209c..780e0c692c05 100644
>>> --- a/clang/lib/CodeGen/CGDebugInfo.cpp
>>> +++ b/clang/lib/CodeGen/CGDebugInfo.cpp
>>> @@ -3252,7 +3252,6 @@ llvm::DIType *CGDebugInfo::CreateTypeNode(QualType
>>> Ty, llvm::DIFile *Unit) {
>>>    case Type::TypeOf:
>>>    case Type::Decltype:
>>>    case Type::UnaryTransform:
>>> -  case Type::PackExpansion:
>>>      break;
>>>    }
>>>
>>>
>>> diff  --git a/clang/lib/CodeGen/CodeGenFunction.cpp
>>> b/clang/lib/CodeGen/CodeGenFunction.cpp
>>> index 8ce488f35dd3..8f79cc77f0e6 100644
>>> --- a/clang/lib/CodeGen/CodeGenFunction.cpp
>>> +++ b/clang/lib/CodeGen/CodeGenFunction.cpp
>>> @@ -2075,7 +2075,6 @@ void
>>> CodeGenFunction::EmitVariablyModifiedType(QualType type) {
>>>      case Type::UnaryTransform:
>>>      case Type::Attributed:
>>>      case Type::SubstTemplateTypeParm:
>>> -    case Type::PackExpansion:
>>>      case Type::MacroQualified:
>>>        // Keep walking after single level desugaring.
>>>        type = type.getSingleStepDesugaredType(getContext());
>>>
>>> diff  --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
>>> index 21d3bbf419a9..bb0b1fa49851 100644
>>> --- a/clang/lib/Sema/SemaExpr.cpp
>>> +++ b/clang/lib/Sema/SemaExpr.cpp
>>> @@ -4345,7 +4345,6 @@ static void captureVariablyModifiedType(ASTContext
>>> &Context, QualType T,
>>>      case Type::UnaryTransform:
>>>      case Type::Attributed:
>>>      case Type::SubstTemplateTypeParm:
>>> -    case Type::PackExpansion:
>>>      case Type::MacroQualified:
>>>        // Keep walking after single level desugaring.
>>>        T = T.getSingleStepDesugaredType(Context);
>>>
>>> diff  --git a/clang/lib/Sema/SemaLambda.cpp
>>> b/clang/lib/Sema/SemaLambda.cpp
>>> index 657ed13f207a..dc74f6e2f7dc 100644
>>> --- a/clang/lib/Sema/SemaLambda.cpp
>>> +++ b/clang/lib/Sema/SemaLambda.cpp
>>> @@ -803,7 +803,8 @@ QualType Sema::buildLambdaInitCaptureInitialization(
>>>        Diag(EllipsisLoc, getLangOpts().CPlusPlus20
>>>                              ? diag::warn_cxx17_compat_init_capture_pack
>>>                              : diag::ext_init_capture_pack);
>>> -      DeductType = Context.getPackExpansionType(DeductType,
>>> NumExpansions);
>>> +      DeductType = Context.getPackExpansionType(DeductType,
>>> NumExpansions,
>>> +
>>> /*ExpectPackInType=*/false);
>>>
>>>  TLB.push<PackExpansionTypeLoc>(DeductType).setEllipsisLoc(EllipsisLoc);
>>>      } else {
>>>        // Just ignore the ellipsis for now and form a non-pack variable.
>>> We'll
>>>
>>> diff  --git a/clang/lib/Sema/SemaTemplateVariadic.cpp
>>> b/clang/lib/Sema/SemaTemplateVariadic.cpp
>>> index 7b77d1cb482a..259cc5165776 100644
>>> --- a/clang/lib/Sema/SemaTemplateVariadic.cpp
>>> +++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
>>> @@ -614,7 +614,8 @@ QualType Sema::CheckPackExpansion(QualType Pattern,
>>> SourceRange PatternRange,
>>>      return QualType();
>>>    }
>>>
>>> -  return Context.getPackExpansionType(Pattern, NumExpansions);
>>> +  return Context.getPackExpansionType(Pattern, NumExpansions,
>>> +                                      /*ExpectPackInType=*/false);
>>>  }
>>>
>>>  ExprResult Sema::ActOnPackExpansion(Expr *Pattern, SourceLocation
>>> EllipsisLoc) {
>>>
>>> diff  --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
>>> index 3eabe7ca6ffe..4c7eece68bca 100644
>>> --- a/clang/lib/Sema/SemaType.cpp
>>> +++ b/clang/lib/Sema/SemaType.cpp
>>> @@ -5516,7 +5516,7 @@ static TypeSourceInfo
>>> *GetFullTypeForDeclarator(TypeProcessingState &state,
>>>            << T <<  D.getSourceRange();
>>>          D.setEllipsisLoc(SourceLocation());
>>>        } else {
>>> -        T = Context.getPackExpansionType(T, None);
>>> +        T = Context.getPackExpansionType(T, None,
>>> /*ExpectPackInType=*/false);
>>>        }
>>>        break;
>>>      case DeclaratorContext::TemplateParamContext:
>>>
>>> diff  --git a/clang/test/SemaTemplate/alias-template-nondependent.cpp
>>> b/clang/test/SemaTemplate/alias-template-nondependent.cpp
>>> new file mode 100644
>>> index 000000000000..e8ea16483a09
>>> --- /dev/null
>>> +++ b/clang/test/SemaTemplate/alias-template-nondependent.cpp
>>> @@ -0,0 +1,24 @@
>>> +// RUN: %clang_cc1 -std=c++20 -verify %s
>>> +
>>> +namespace PR46377 {
>>> +  template<typename> using IntPtr = int*;
>>> +  template<typename ...T> auto non_dependent_typedef() {
>>> +    typedef int(*P)(IntPtr<T>...);
>>> +    return P();
>>> +  }
>>> +  template<typename ...T> auto non_dependent_alias() {
>>> +    using P = int(*)(IntPtr<T>...);
>>> +    return P();
>>> +  }
>>> +  template<typename ...T> auto non_dependent_via_sizeof() {
>>> +    using P = int(*)(int(...pack)[sizeof(sizeof(T))]); //
>>> expected-error {{invalid application of 'sizeof'}}
>>> +    return P();
>>> +  }
>>> +
>>> +  using a = int (*)(int*, int*);
>>> +  using a = decltype(non_dependent_typedef<void, void>());
>>> +  using a = decltype(non_dependent_alias<void, void>());
>>> +  using a = decltype(non_dependent_via_sizeof<float, float>());
>>> +
>>> +  using b = decltype(non_dependent_via_sizeof<float, void>()); //
>>> expected-note {{instantiation of}}
>>> +}
>>>
>>>
>>>
>>> _______________________________________________
>>> cfe-commits mailing list
>>> cfe-commits at lists.llvm.org
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>>
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