https://github.com/LYP951018 updated https://github.com/llvm/llvm-project/pull/70548
From a5929ddc33057416cee75d91f13a1252f4357524 Mon Sep 17 00:00:00 2001 From: letrec <liuyupei951...@hotmail.com> Date: Sat, 28 Oct 2023 18:05:36 +0800 Subject: [PATCH] Defer the instantiation of explicit-specifier after constraint checking --- clang/docs/ReleaseNotes.rst | 4 ++ clang/include/clang/Sema/Sema.h | 3 + clang/lib/Sema/SemaTemplateDeduction.cpp | 59 +++++++++++++++++++ .../lib/Sema/SemaTemplateInstantiateDecl.cpp | 40 ++++++++----- .../SemaCXX/cxx2a-explicit-bool-deferred.cpp | 31 ++++++++++ 5 files changed, 123 insertions(+), 14 deletions(-) create mode 100644 clang/test/SemaCXX/cxx2a-explicit-bool-deferred.cpp diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 2595737e8b3b143..203111b829bd0c6 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -670,6 +670,10 @@ Bug Fixes to C++ Support default initializing a base class in a constant expression context. Fixes: (`#69890 <https://github.com/llvm/llvm-project/issues/69890>`_) +- Clang now defers the instantiation of explicit specifier until constraint checking + completes (except deduction guides). Fixes: + (`#59827 <https://github.com/llvm/llvm-project/issues/59827>`_) + Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ - Fixed an import failure of recursive friend class template. diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h index 1e9752345ffd173..93fd6507db3d78a 100644 --- a/clang/include/clang/Sema/Sema.h +++ b/clang/include/clang/Sema/Sema.h @@ -10430,6 +10430,9 @@ class Sema final { const CXXConstructorDecl *Tmpl, const MultiLevelTemplateArgumentList &TemplateArgs); + ExplicitSpecifier instantiateExplicitSpecifier( + const MultiLevelTemplateArgumentList &TemplateArgs, ExplicitSpecifier ES); + NamedDecl *FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D, const MultiLevelTemplateArgumentList &TemplateArgs, bool FindingInstantiatedContext = false); diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp index 0b3f0247ea3bee3..f06332770f51d1f 100644 --- a/clang/lib/Sema/SemaTemplateDeduction.cpp +++ b/clang/lib/Sema/SemaTemplateDeduction.cpp @@ -3553,6 +3553,56 @@ static unsigned getPackIndexForParam(Sema &S, llvm_unreachable("parameter index would not be produced from template"); } +// if `Specialization` is a `CXXConstructorDecl` or `CXXConversionDecl` +// we try to instantiate and update its explicit specifier after constraint +// checking. +static Sema::TemplateDeductionResult +tryInstantiateExplicitSpecifier(Sema &S, FunctionDecl *Specialization, + const MultiLevelTemplateArgumentList &SubstArgs, + TemplateDeductionInfo &Info, + FunctionTemplateDecl *FunctionTemplate, + ArrayRef<TemplateArgument> DeducedArgs) { + + const auto TryInstantiateExplicitSpecifierForSingleDecl = + [&](auto *ExplicitDecl) { + ExplicitSpecifier ExplicitSpecifier = + ExplicitDecl->getExplicitSpecifier(); + Expr *const Expr = ExplicitSpecifier.getExpr(); + if (!Expr) { + return Sema::TDK_Success; + } + if (!Expr->isValueDependent()) { + return Sema::TDK_Success; + } + // TemplateDeclInstantiator::InitFunctionInstantiation set the + // ActiveInstType to TemplateInstantiation, but we need + // to enable SFINAE when instantiating explicit specifier. + Sema::InstantiatingTemplate Inst( + S, Info.getLocation(), FunctionTemplate, DeducedArgs, + Sema::CodeSynthesisContext::DeducedTemplateArgumentSubstitution, + Info); + const auto Instantiated = + S.instantiateExplicitSpecifier(SubstArgs, ExplicitSpecifier); + if (Instantiated.isInvalid()) { + ExplicitDecl->setInvalidDecl(true); + return clang::Sema::TDK_SubstitutionFailure; + } + ExplicitDecl->setExplicitSpecifier(Instantiated); + return clang::Sema::TDK_Success; + }; + Sema::TemplateDeductionResult DeductionResult = clang::Sema::TDK_Success; + if (CXXConstructorDecl *ConstructorDecl = + dyn_cast_or_null<CXXConstructorDecl>(Specialization)) { + DeductionResult = + TryInstantiateExplicitSpecifierForSingleDecl(ConstructorDecl); + } else if (CXXConversionDecl *ConversionDecl = + dyn_cast_or_null<CXXConversionDecl>(Specialization)) { + DeductionResult = + TryInstantiateExplicitSpecifierForSingleDecl(ConversionDecl); + } + return DeductionResult; +} + /// Finish template argument deduction for a function template, /// checking the deduced template arguments for completeness and forming /// the function template specialization. @@ -3682,6 +3732,15 @@ Sema::TemplateDeductionResult Sema::FinishTemplateArgumentDeduction( } } + // We skipped the instantiation of the explicit-specifier during subst the + // decl before. Now, we try to instantiate it back if the Specialization is a + // constructor or a conversion. + if (TDK_Success != + tryInstantiateExplicitSpecifier(*this, Specialization, SubstArgs, Info, + FunctionTemplate, DeducedArgs)) { + return TDK_SubstitutionFailure; + } + if (OriginalCallArgs) { // C++ [temp.deduct.call]p4: // In general, the deduction process attempts to find template argument diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp index 78a7892a35a320b..163dbef03e80a4d 100644 --- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp +++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp @@ -563,18 +563,16 @@ static void instantiateDependentAMDGPUFlatWorkGroupSizeAttr( S.addAMDGPUFlatWorkGroupSizeAttr(New, Attr, MinExpr, MaxExpr); } -static ExplicitSpecifier -instantiateExplicitSpecifier(Sema &S, - const MultiLevelTemplateArgumentList &TemplateArgs, - ExplicitSpecifier ES, FunctionDecl *New) { +ExplicitSpecifier Sema::instantiateExplicitSpecifier( + const MultiLevelTemplateArgumentList &TemplateArgs, ExplicitSpecifier ES) { if (!ES.getExpr()) return ES; Expr *OldCond = ES.getExpr(); Expr *Cond = nullptr; { EnterExpressionEvaluationContext Unevaluated( - S, Sema::ExpressionEvaluationContext::ConstantEvaluated); - ExprResult SubstResult = S.SubstExpr(OldCond, TemplateArgs); + *this, Sema::ExpressionEvaluationContext::ConstantEvaluated); + ExprResult SubstResult = SubstExpr(OldCond, TemplateArgs); if (SubstResult.isInvalid()) { return ExplicitSpecifier::Invalid(); } @@ -582,7 +580,7 @@ instantiateExplicitSpecifier(Sema &S, } ExplicitSpecifier Result(Cond, ES.getKind()); if (!Cond->isTypeDependent()) - S.tryResolveExplicitSpecifier(Result); + tryResolveExplicitSpecifier(Result); return Result; } @@ -2073,8 +2071,8 @@ Decl *TemplateDeclInstantiator::VisitFunctionDecl( ExplicitSpecifier InstantiatedExplicitSpecifier; if (auto *DGuide = dyn_cast<CXXDeductionGuideDecl>(D)) { - InstantiatedExplicitSpecifier = instantiateExplicitSpecifier( - SemaRef, TemplateArgs, DGuide->getExplicitSpecifier(), DGuide); + InstantiatedExplicitSpecifier = SemaRef.instantiateExplicitSpecifier( + TemplateArgs, DGuide->getExplicitSpecifier()); if (InstantiatedExplicitSpecifier.isInvalid()) return nullptr; } @@ -2453,11 +2451,25 @@ Decl *TemplateDeclInstantiator::VisitCXXMethodDecl( } } - ExplicitSpecifier InstantiatedExplicitSpecifier = - instantiateExplicitSpecifier(SemaRef, TemplateArgs, - ExplicitSpecifier::getFromDecl(D), D); - if (InstantiatedExplicitSpecifier.isInvalid()) - return nullptr; + auto InstantiatedExplicitSpecifier = ExplicitSpecifier::getFromDecl(D); + // deduction guides need this + const bool CouldInstantiate = + InstantiatedExplicitSpecifier.getExpr() == nullptr || + !InstantiatedExplicitSpecifier.getExpr()->isValueDependent(); + + // Delay the instantiation of the explicit-specifier until after the + // constraints are checked during template argument deduction. + if (CouldInstantiate || + SemaRef.CodeSynthesisContexts.back().Kind != + Sema::CodeSynthesisContext::DeducedTemplateArgumentSubstitution) { + InstantiatedExplicitSpecifier = SemaRef.instantiateExplicitSpecifier( + TemplateArgs, InstantiatedExplicitSpecifier); + + if (InstantiatedExplicitSpecifier.isInvalid()) + return nullptr; + } else { + InstantiatedExplicitSpecifier.setKind(ExplicitSpecKind::Unresolved); + } // Implicit destructors/constructors created for local classes in // DeclareImplicit* (see SemaDeclCXX.cpp) might not have an associated TSI. diff --git a/clang/test/SemaCXX/cxx2a-explicit-bool-deferred.cpp b/clang/test/SemaCXX/cxx2a-explicit-bool-deferred.cpp new file mode 100644 index 000000000000000..4d667008f2e2763 --- /dev/null +++ b/clang/test/SemaCXX/cxx2a-explicit-bool-deferred.cpp @@ -0,0 +1,31 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++2a %s + +template <typename T1, typename T2> struct is_same { + static constexpr bool value = false; +}; + +template <typename T> struct is_same<T, T> { + static constexpr bool value = true; +}; + +template <class T, class U> +concept SameHelper = is_same<T, U>::value; +template <class T, class U> +concept same_as = SameHelper<T, U> && SameHelper<U, T>; + +namespace deferred_instantiation { +template <class X> constexpr X do_not_instantiate() { return nullptr; } + +struct T { + template <same_as<float> X> explicit(do_not_instantiate<X>()) T(X) {} + + T(int) {} +}; + +T t(5); +// expected-error@17{{cannot initialize}} +// expected-note@20{{in instantiation of function template specialization}} +// expected-note@30{{while substituting deduced template arguments}} +// expected-note@30{{in instantiation of function template specialization}} +T t2(5.0f); +} // namespace deferred_instantiation _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
