https://github.com/Serosh-commits updated https://github.com/llvm/llvm-project/pull/180407
>From cf731e642abeece29ee5f397123b28a84bd2a428 Mon Sep 17 00:00:00 2001 From: Serosh-commits <[email protected]> Date: Sun, 8 Feb 2026 17:40:06 +0530 Subject: [PATCH 1/2] [clang][sema] fix crash on builtin template ids with dependent packs (gh180307) --- clang/lib/Sema/SemaTemplate.cpp | 28 ++++++------- .../builtin_templates_invalid_parameters.cpp | 41 +++++++++++++++++++ 2 files changed, 53 insertions(+), 16 deletions(-) create mode 100644 clang/test/SemaCXX/builtin_templates_invalid_parameters.cpp diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp index 3497ff7856eed..c54392418e25e 100644 --- a/clang/lib/Sema/SemaTemplate.cpp +++ b/clang/lib/Sema/SemaTemplate.cpp @@ -3406,10 +3406,22 @@ static QualType checkBuiltinTemplateIdType( Sema &SemaRef, ElaboratedTypeKeyword Keyword, BuiltinTemplateDecl *BTD, ArrayRef<TemplateArgument> Converted, SourceLocation TemplateLoc, TemplateArgumentListInfo &TemplateArgs) { + TemplateParameterList *Params = BTD->getTemplateParameters(); + unsigned RequiredArgs = Params->size(); + if (Params->hasParameterPack()) { + if (Converted.size() < RequiredArgs) + return QualType(); + } else { + if (Converted.size() != RequiredArgs) + return QualType(); + } + ASTContext &Context = SemaRef.getASTContext(); switch (BTD->getBuiltinTemplateKind()) { case BTK__make_integer_seq: { + if (Converted[2].isDependent()) + return QualType(); // Specializations of __make_integer_seq<S, T, N> are treated like // S<T, 0, ..., N-1>. @@ -3423,8 +3435,6 @@ static QualType checkBuiltinTemplateIdType( } TemplateArgument NumArgsArg = Converted[2]; - if (NumArgsArg.isDependent()) - return QualType(); TemplateArgumentListInfo SyntheticTemplateArgs; // The type argument, wrapped in substitution sugar, gets reused as the @@ -3459,12 +3469,6 @@ static QualType checkBuiltinTemplateIdType( } case BTK__type_pack_element: { - // Specializations of - // __type_pack_element<Index, T_1, ..., T_N> - // are treated like T_Index. - assert(Converted.size() == 2 && - "__type_pack_element should be given an index and a parameter pack"); - TemplateArgument IndexArg = Converted[0], Ts = Converted[1]; if (IndexArg.isDependent() || Ts.isDependent()) return QualType(); @@ -3485,7 +3489,6 @@ static QualType checkBuiltinTemplateIdType( } case BTK__builtin_common_type: { - assert(Converted.size() == 4); if (llvm::any_of(Converted, [](auto &C) { return C.isDependent(); })) return QualType(); @@ -3508,8 +3511,6 @@ static QualType checkBuiltinTemplateIdType( } case BTK__hlsl_spirv_type: { - assert(Converted.size() == 4); - if (!Context.getTargetInfo().getTriple().isSPIRV()) { SemaRef.Diag(TemplateLoc, diag::err_hlsl_spirv_only) << BTD; } @@ -3537,12 +3538,7 @@ static QualType checkBuiltinTemplateIdType( return Context.getHLSLInlineSpirvType(Opcode, Size, Alignment, Operands); } case BTK__builtin_dedup_pack: { - assert(Converted.size() == 1 && "__builtin_dedup_pack should be given " - "a parameter pack"); TemplateArgument Ts = Converted[0]; - // Delay the computation until we can compute the final result. We choose - // not to remove the duplicates upfront before substitution to keep the code - // simple. if (Ts.isDependent()) return QualType(); assert(Ts.getKind() == clang::TemplateArgument::Pack); diff --git a/clang/test/SemaCXX/builtin_templates_invalid_parameters.cpp b/clang/test/SemaCXX/builtin_templates_invalid_parameters.cpp new file mode 100644 index 0000000000000..dd74bbd1d900d --- /dev/null +++ b/clang/test/SemaCXX/builtin_templates_invalid_parameters.cpp @@ -0,0 +1,41 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s +// expected-error@* 2 {{template argument for non-type template parameter must be an expression}} + +using SizeT = decltype(sizeof(int)); + +// Dependent cases that previously crashed but now return QualType() gracefully. +template <SizeT... Seq> // expected-note {{template parameter is declared here}} +using gh180307 = __type_pack_element<Seq...>; + +template <typename T> +using gh180307_bis = __make_integer_seq<gh180307, T>; +// expected-note@-1 {{template template argument has different template parameters than its corresponding template template parameter}} + +// Eager expansion checks: Built-in templates should expand even if the +// destination template OR the type argument is dependent, provided the size is known. +template <template <typename T, T... Ints> class Seq> +using test_make_integer_seq_eager = __make_integer_seq<Seq, int, 2>; + +template <typename T, T... Ints> struct MySeq; +using check_eager = test_make_integer_seq_eager<MySeq>; +using check_eager = MySeq<int, 0, 1>; + +template <typename T> +using test_make_integer_seq_type_dependent = __make_integer_seq<MySeq, T, 2>; +using check_type_eager = test_make_integer_seq_type_dependent<int>; +using check_type_eager = MySeq<int, 0, 1>; + +// Too many arguments tests +template <int N> struct S; // expected-note {{template parameter is declared here}} +using too_many_args = __make_integer_seq<S, int, 10, int>; +// expected-note@-1 {{template template argument has different template parameters than its corresponding template template parameter}} + +// Too few arguments tests +template <SizeT Index> +using too_few_args = __type_pack_element<Index>; + +// Verify that too_few_args doesn't crash on instantiation either +// (It should just be an invalid type) +template <SizeT I> struct Wrap { + using type = too_few_args<I>; +}; >From 8ffca73b3fc88fada9231716525abac112bf7a55 Mon Sep 17 00:00:00 2001 From: Serosh-commits <[email protected]> Date: Thu, 12 Feb 2026 22:11:43 +0530 Subject: [PATCH 2/2] [clang][sema] address reviewer feedback for builtin template crash (gh180307) --- clang/lib/Sema/SemaTemplate.cpp | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp index c54392418e25e..274235c6b226e 100644 --- a/clang/lib/Sema/SemaTemplate.cpp +++ b/clang/lib/Sema/SemaTemplate.cpp @@ -3426,9 +3426,13 @@ static QualType checkBuiltinTemplateIdType( // S<T, 0, ..., N-1>. QualType OrigType = Converted[1].getAsType(); + if (OrigType->isDependentType()) + return QualType(); + // C++14 [inteseq.intseq]p1: // T shall be an integer type. - if (!OrigType->isDependentType() && !OrigType->isIntegralType(Context)) { + assert(!OrigType->isDependentType()); + if (!OrigType->isIntegralType(Context)) { SemaRef.Diag(TemplateArgs[1].getLocation(), diag::err_integer_sequence_integral_element_type); return QualType(); _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
