Hi Hans, This is a safe change that fixes a crash; it'd be good to get this into clang 8.
Thanks! On Sun, 27 Jan 2019, 11:19 Nicolas Lesser via cfe-commits, < cfe-commits@lists.llvm.org> wrote: > Author: rakete1111 > Date: Sun Jan 27 11:19:59 2019 > New Revision: 352323 > > URL: http://llvm.org/viewvc/llvm-project?rev=352323&view=rev > Log: > [SemaCXX] Fix ICE with structure bindings to members of template > > Summary: > Trying to use structure binding with a structure that doesn't implement > std::tuple_size, should unpack the data members. When the struct is a > template though, clang might hit an assertion (if the type has not been > completed before), because CXXRecordDecl::DefinitionData is nullptr. > > This commit fixes the problem by completing the type while trying to > decompose the structured binding. > > The ICE happens in real world code, for example, when trying to iterate > a protobuf generated map with a range-based for loop and structure > bindings (because google::protobuf::MapPair is a template and doesn't > support std::tuple_size). > > Reported-by: nicholas....@nlsun.com > > Patch by Daniele Di Proietto > > Reviewers: #clang, rsmith > > Reviewed By: #clang, rsmith > > Subscribers: cpplearner, Rakete1111, cfe-commits > > Tags: #clang > > Differential Revision: https://reviews.llvm.org/D56974 > > > Modified: > cfe/trunk/lib/Sema/SemaDeclCXX.cpp > cfe/trunk/test/SemaCXX/cxx1z-decomposition.cpp > > Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=352323&r1=352322&r2=352323&view=diff > > ============================================================================== > --- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original) > +++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Sun Jan 27 11:19:59 2019 > @@ -1300,6 +1300,10 @@ static DeclAccessPair findDecomposableBa > static bool checkMemberDecomposition(Sema &S, ArrayRef<BindingDecl*> > Bindings, > ValueDecl *Src, QualType DecompType, > const CXXRecordDecl *OrigRD) { > + if (S.RequireCompleteType(Src->getLocation(), DecompType, > + diag::err_incomplete_type)) > + return true; > + > CXXCastPath BasePath; > DeclAccessPair BasePair = > findDecomposableBaseClass(S, Src->getLocation(), OrigRD, BasePath); > > Modified: cfe/trunk/test/SemaCXX/cxx1z-decomposition.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1z-decomposition.cpp?rev=352323&r1=352322&r2=352323&view=diff > > ============================================================================== > --- cfe/trunk/test/SemaCXX/cxx1z-decomposition.cpp (original) > +++ cfe/trunk/test/SemaCXX/cxx1z-decomposition.cpp Sun Jan 27 11:19:59 2019 > @@ -81,4 +81,21 @@ struct PR37352 { > void f() { static auto [a] = *this; } // expected-error {{cannot be > declared 'static'}} > }; > > +namespace instantiate_template { > + > +template <typename T1, typename T2> > +struct pair { > + T1 a; > + T2 b; > +}; > + > +const pair<int, int> &f1(); > + > +int f2() { > + const auto &[a, b] = f1(); > + return a + b; > +} > + > +} // namespace instantiate_template > + > // FIXME: by-value array copies > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >
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