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[clang] Remove libstdc++ friend template hack 

this hack is for a now-unsupported version of libstdc++

Differential Revision: https://reviews.llvm.org/D101392
This commit is contained in:
Nathan Sidwell 2021-04-27 12:03:40 -07:00
parent 69a3269250
commit fe4c9b3cb0
2 changed files with 16 additions and 44 deletions
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38
clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
View File

@ -1518,48 +1518,18 @@ Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
return nullptr;
}
bool AdoptedPreviousTemplateParams = false;
if (PrevClassTemplate) {
bool Complain = true;
// HACK: libstdc++ 4.2.1 contains an ill-formed friend class
// template for struct std::tr1::__detail::_Map_base, where the
// template parameters of the friend declaration don't match the
// template parameters of the original declaration. In this one
// case, we don't complain about the ill-formed friend
// declaration.
if (isFriend && Pattern->getIdentifier() &&
Pattern->getIdentifier()->isStr("_Map_base") &&
DC->isNamespace() &&
cast<NamespaceDecl>(DC)->getIdentifier() &&
cast<NamespaceDecl>(DC)->getIdentifier()->isStr("__detail")) {
DeclContext *DCParent = DC->getParent();
if (DCParent->isNamespace() &&
cast<NamespaceDecl>(DCParent)->getIdentifier() &&
cast<NamespaceDecl>(DCParent)->getIdentifier()->isStr("tr1")) {
if (cast<Decl>(DCParent)->isInStdNamespace())
Complain = false;
}
}
TemplateParameterList *PrevParams
= PrevClassTemplate->getMostRecentDecl()->getTemplateParameters();
// Make sure the parameter lists match.
if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
Complain,
Sema::TPL_TemplateMatch)) {
if (Complain)
return nullptr;
AdoptedPreviousTemplateParams = true;
InstParams = PrevParams;
}
if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams, true,
Sema::TPL_TemplateMatch))
return nullptr;
// Do some additional validation, then merge default arguments
// from the existing declarations.
if (!AdoptedPreviousTemplateParams &&
SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
if (SemaRef.CheckTemplateParameterList(InstParams, PrevParams,
Sema::TPC_ClassTemplate))
return nullptr;
}

22
clang/test/SemaCXX/libstdcxx_map_base_hack.cpp
View File

@ -1,25 +1,27 @@
// RUN: %clang_cc1 -fsyntax-only %s
// RUN: %clang_cc1 -fsyntax-only -verify %s
// libstdc++ 4.2.x contains a bug where a friend struct template
// declaration for std::tr1::__detail::_Map base has different
// template arguments than the real declaration. Clang has an
// egregious hack to work around this problem, since we can't modify
// all of the world's libstdc++'s.
// template arguments than the real declaration.
// We no longer contain the hack to workaround the problem. Verify that
// std::tr1::__detail::Map_base is not a unique and special snowflake.
namespace std { namespace tr1 { namespace __detail {
template<typename _Key, typename _Value, typename _Ex, bool __unique,
typename _Hashtable>
struct _Map_base { };
template <typename _Key, typename _Value, typename _Ex, bool __unique,
// expected-note@-1{{previous template declaration}}
typename _Hashtable>
struct _Map_base {};
} } }
namespace std { namespace tr1 {
template<typename T>
struct X1 {
template<typename _Key2, typename _Pair, typename _Hashtable>
template <typename _Key2, typename _Pair, typename _Hashtable>
// expected-error@-1{{too few template parameters}}
friend struct __detail::_Map_base;
};
} }
std::tr1::X1<int> x1i;
std::tr1::X1<int> x1i; // expected-note{{in instantiation}}