r304862 - Fix a couple of class template argument deduction crashes with libc++'s tuple.
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Tue Jun 6 19:42:27 PDT 2017
Author: rsmith
Date: Tue Jun 6 21:42:27 2017
New Revision: 304862
URL: http://llvm.org/viewvc/llvm-project?rev=304862&view=rev
Log:
Fix a couple of class template argument deduction crashes with libc++'s tuple.
RecursiveASTVisitor was not properly recursing through a
SubstTemplateTypeParmTypes, resulting in crashes in pack expansion where we
couldn't always find an unexpanded pack within a pack expansion.
We also have an issue where substitution of deduced template arguments for an
implicit deduction guide creates the "impossible" case of naming a
non-dependent member of the current instantiation, but within a specialization
that is actually instantiated from a different (partial/explicit)
specialization of the template. We resolve this by declaring that constructors
that do so can only be used to deduce specializations of the primary template.
I'm running this past CWG to see if people agree this is the right thing to do.
Modified:
cfe/trunk/include/clang/AST/RecursiveASTVisitor.h
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp
cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
cfe/trunk/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
Modified: cfe/trunk/include/clang/AST/RecursiveASTVisitor.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/RecursiveASTVisitor.h?rev=304862&r1=304861&r2=304862&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/RecursiveASTVisitor.h (original)
+++ cfe/trunk/include/clang/AST/RecursiveASTVisitor.h Tue Jun 6 21:42:27 2017
@@ -1021,8 +1021,12 @@ DEF_TRAVERSE_TYPE(DeducedTemplateSpecial
DEF_TRAVERSE_TYPE(RecordType, {})
DEF_TRAVERSE_TYPE(EnumType, {})
DEF_TRAVERSE_TYPE(TemplateTypeParmType, {})
-DEF_TRAVERSE_TYPE(SubstTemplateTypeParmType, {})
-DEF_TRAVERSE_TYPE(SubstTemplateTypeParmPackType, {})
+DEF_TRAVERSE_TYPE(SubstTemplateTypeParmType, {
+ TRY_TO(TraverseType(T->getReplacementType()));
+})
+DEF_TRAVERSE_TYPE(SubstTemplateTypeParmPackType, {
+ TRY_TO(TraverseTemplateArgument(T->getArgumentPack()));
+})
DEF_TRAVERSE_TYPE(TemplateSpecializationType, {
TRY_TO(TraverseTemplateName(T->getTemplateName()));
@@ -1249,8 +1253,12 @@ DEF_TRAVERSE_TYPELOC(DeducedTemplateSpec
DEF_TRAVERSE_TYPELOC(RecordType, {})
DEF_TRAVERSE_TYPELOC(EnumType, {})
DEF_TRAVERSE_TYPELOC(TemplateTypeParmType, {})
-DEF_TRAVERSE_TYPELOC(SubstTemplateTypeParmType, {})
-DEF_TRAVERSE_TYPELOC(SubstTemplateTypeParmPackType, {})
+DEF_TRAVERSE_TYPELOC(SubstTemplateTypeParmType, {
+ TRY_TO(TraverseType(TL.getTypePtr()->getReplacementType()));
+})
+DEF_TRAVERSE_TYPELOC(SubstTemplateTypeParmPackType, {
+ TRY_TO(TraverseTemplateArgument(TL.getTypePtr()->getArgumentPack()));
+})
// FIXME: use the loc for the template name?
DEF_TRAVERSE_TYPELOC(TemplateSpecializationType, {
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=304862&r1=304861&r2=304862&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Jun 6 21:42:27 2017
@@ -5613,6 +5613,11 @@ def err_enumerator_does_not_exist : Erro
def note_enum_specialized_here : Note<
"enum %0 was explicitly specialized here">;
+def err_specialization_not_primary_template : Error<
+ "cannot reference member of primary template because deduced class "
+ "template specialization %0 is %select{instantiated from a partial|"
+ "an explicit}1 specialization">;
+
def err_member_redeclared : Error<"class member cannot be redeclared">;
def ext_member_redeclared : ExtWarn<"class member cannot be redeclared">,
InGroup<RedeclaredClassMember>;
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=304862&r1=304861&r2=304862&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Tue Jun 6 21:42:27 2017
@@ -7640,6 +7640,9 @@ public:
LateInstantiatedAttrVec *LateAttrs = nullptr,
LocalInstantiationScope *OuterMostScope = nullptr);
+ bool usesPartialOrExplicitSpecialization(
+ SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec);
+
bool
InstantiateClassTemplateSpecialization(SourceLocation PointOfInstantiation,
ClassTemplateSpecializationDecl *ClassTemplateSpec,
Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp?rev=304862&r1=304861&r2=304862&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp Tue Jun 6 21:42:27 2017
@@ -2350,6 +2350,25 @@ namespace {
};
}
+bool Sema::usesPartialOrExplicitSpecialization(
+ SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec) {
+ if (ClassTemplateSpec->getTemplateSpecializationKind() ==
+ TSK_ExplicitSpecialization)
+ return true;
+
+ SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;
+ ClassTemplateSpec->getSpecializedTemplate()
+ ->getPartialSpecializations(PartialSpecs);
+ for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
+ TemplateDeductionInfo Info(Loc);
+ if (!DeduceTemplateArguments(PartialSpecs[I],
+ ClassTemplateSpec->getTemplateArgs(), Info))
+ return true;
+ }
+
+ return false;
+}
+
/// Get the instantiation pattern to use to instantiate the definition of a
/// given ClassTemplateSpecializationDecl (either the pattern of the primary
/// template or of a partial specialization).
Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp?rev=304862&r1=304861&r2=304862&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Tue Jun 6 21:42:27 2017
@@ -5000,7 +5000,21 @@ NamedDecl *Sema::FindInstantiatedDecl(So
QualType T = CheckTemplateIdType(TemplateName(TD), Loc, Args);
if (T.isNull())
return nullptr;
- DC = T->getAsCXXRecordDecl();
+ auto *SubstRecord = T->getAsCXXRecordDecl();
+ assert(SubstRecord && "class template id not a class type?");
+ // Check that this template-id names the primary template and not a
+ // partial or explicit specialization. (In the latter cases, it's
+ // meaningless to attempt to find an instantiation of D within the
+ // specialization.)
+ // FIXME: The standard doesn't say what should happen here.
+ if (usesPartialOrExplicitSpecialization(Loc,
+ cast<ClassTemplateSpecializationDecl>(SubstRecord))) {
+ Diag(Loc, diag::err_specialization_not_primary_template)
+ << T << (SubstRecord->getTemplateSpecializationKind() ==
+ TSK_ExplicitSpecialization);
+ return nullptr;
+ }
+ DC = SubstRecord;
continue;
}
}
Modified: cfe/trunk/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp?rev=304862&r1=304861&r2=304862&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp (original)
+++ cfe/trunk/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp Tue Jun 6 21:42:27 2017
@@ -248,3 +248,27 @@ namespace variadic {
};
Z z(1, a, b);
}
+
+namespace tuple_tests {
+ // The converting n-ary constructor appears viable, deducing T as an empty
+ // pack (until we check its SFINAE constraints).
+ namespace libcxx_1 {
+ template<class ...T> struct tuple {
+ template<class ...Args> struct X { static const bool value = false; };
+ template<class ...U, bool Y = X<U...>::value> tuple(U &&...u);
+ };
+ tuple a = {1, 2, 3};
+ }
+
+ // Don't get caught by surprise when X<...> doesn't even exist in the
+ // selected specialization!
+ namespace libcxx_2 {
+ template<class ...T> struct tuple { // expected-note {{candidate}}
+ template<class ...Args> struct X { static const bool value = false; };
+ template<class ...U, bool Y = X<U...>::value> tuple(U &&...u);
+ // expected-note at -1 {{substitution failure [with T = <>, U = <int, int, int>]: cannot reference member of primary template because deduced class template specialization 'tuple<>' is an explicit specialization}}
+ };
+ template <> class tuple<> {};
+ tuple a = {1, 2, 3}; // expected-error {{no viable constructor or deduction guide}}
+ }
+}
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