From 926c4b486a08f698cd3a367fd6f1a3a07604358d Mon Sep 17 00:00:00 2001 From: Chandler Carruth Date: Mon, 28 Jun 2010 08:39:25 +0000 Subject: [PATCH] Partial fix for PR7267 based on comments by John McCall on an earlier patch. This is more targeted, as it simply provides toggle actions for the parser to turn access checking on and off. We then use these to suppress access checking only while we parse the template-id (included scope specifier) of an explicit instantiation and explicit specialization of a class template. The specialization behavior is an extension, as it seems likely a defect that the standard did not exempt them as it does explicit instantiations. This allows the very common practice of specializing trait classes to work for private, internal types. This doesn't address instantiating or specializing function templates, although those apparently already partially work. The naming and style for the Action layer isn't my favorite, comments and suggestions would be appreciated there. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@106993 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/clang/Parse/Action.h | 10 +++++++++ lib/Parse/ParseDeclCXX.cpp | 22 +++++++++++++++++++ lib/Sema/Sema.cpp | 4 ++-- lib/Sema/Sema.h | 6 +++++ lib/Sema/SemaAccess.cpp | 15 +++++++++++++ test/CXX/temp/temp.spec/temp.explicit/p11.cpp | 18 +++++++++++++++ 6 files changed, 73 insertions(+), 2 deletions(-) create mode 100644 test/CXX/temp/temp.spec/temp.explicit/p11.cpp diff --git a/include/clang/Parse/Action.h b/include/clang/Parse/Action.h index d8bb8a5b61..fed4361f1a 100644 --- a/include/clang/Parse/Action.h +++ b/include/clang/Parse/Action.h @@ -2278,6 +2278,16 @@ public: return TypeResult(); } + /// \brief Called when the parser begins parsing a construct which should not + /// have access control applied to it. + virtual void ActOnStartSuppressingAccessChecks() { + } + + /// \brief Called when the parser finishes parsing a construct which should + /// not have access control applied to it. + virtual void ActOnStopSuppressingAccessChecks() { + } + //===----------------------- Obj-C Declarations -------------------------===// // ActOnStartClassInterface - this action is called immediately after parsing diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp index 53fc3405bb..ffef288e71 100644 --- a/lib/Parse/ParseDeclCXX.cpp +++ b/lib/Parse/ParseDeclCXX.cpp @@ -613,6 +613,20 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind, ConsumeCodeCompletionToken(); } + // C++03 [temp.explicit] 14.7.2/8: + // The usual access checking rules do not apply to names used to specify + // explicit instantiations. + // + // As an extension we do not perform access checking on the names used to + // specify explicit specializations either. This is important to allow + // specializing traits classes for private types. + bool SuppressingAccessChecks = false; + if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation || + TemplateInfo.Kind == ParsedTemplateInfo::ExplicitSpecialization) { + Actions.ActOnStartSuppressingAccessChecks(); + SuppressingAccessChecks = true; + } + AttributeList *AttrList = 0; // If attributes exist after tag, parse them. if (Tok.is(tok::kw___attribute)) @@ -732,10 +746,18 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind, DS.SetTypeSpecError(); SkipUntil(tok::semi, false, true); TemplateId->Destroy(); + if (SuppressingAccessChecks) + Actions.ActOnStopSuppressingAccessChecks(); + return; } } + // As soon as we're finished parsing the class's template-id, turn access + // checking back on. + if (SuppressingAccessChecks) + Actions.ActOnStopSuppressingAccessChecks(); + // There are four options here. If we have 'struct foo;', then this // is either a forward declaration or a friend declaration, which // have to be treated differently. If we have 'struct foo {...' or diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp index eadc2ad253..d520a78abe 100644 --- a/lib/Sema/Sema.cpp +++ b/lib/Sema/Sema.cpp @@ -125,8 +125,8 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer, IdResolver(pp.getLangOptions()), StdNamespace(0), StdBadAlloc(0), GlobalNewDeleteDeclared(false), CompleteTranslationUnit(CompleteTranslationUnit), - NumSFINAEErrors(0), NonInstantiationEntries(0), - CurrentInstantiationScope(0), TyposCorrected(0), + NumSFINAEErrors(0), SuppressAccessChecking(false), + NonInstantiationEntries(0), CurrentInstantiationScope(0), TyposCorrected(0), AnalysisWarnings(*this) { TUScope = 0; diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h index 9d5e290b2f..fcf5e94149 100644 --- a/lib/Sema/Sema.h +++ b/lib/Sema/Sema.h @@ -2797,6 +2797,12 @@ public: void HandleDelayedAccessCheck(DelayedDiagnostic &DD, Decl *Ctx); + /// A flag to suppress access checking. + bool SuppressAccessChecking; + + void ActOnStartSuppressingAccessChecks(); + void ActOnStopSuppressingAccessChecks(); + enum AbstractDiagSelID { AbstractNone = -1, AbstractReturnType, diff --git a/lib/Sema/SemaAccess.cpp b/lib/Sema/SemaAccess.cpp index 7845f6d0a9..e110e3dfa4 100644 --- a/lib/Sema/SemaAccess.cpp +++ b/lib/Sema/SemaAccess.cpp @@ -1024,6 +1024,9 @@ static Sema::AccessResult CheckAccess(Sema &S, SourceLocation Loc, if (Entity.getAccess() == AS_public) return Sema::AR_accessible; + if (S.SuppressAccessChecking) + return Sema::AR_accessible; + // If we're currently parsing a top-level declaration, delay // diagnostics. This is the only case where parsing a declaration // can actually change our effective context for the purposes of @@ -1334,3 +1337,15 @@ void Sema::CheckLookupAccess(const LookupResult &R) { } } } + +void Sema::ActOnStartSuppressingAccessChecks() { + assert(!SuppressAccessChecking && + "Tried to start access check suppression when already started."); + SuppressAccessChecking = true; +} + +void Sema::ActOnStopSuppressingAccessChecks() { + assert(SuppressAccessChecking && + "Tried to stop access check suprression when already stopped."); + SuppressAccessChecking = false; +} diff --git a/test/CXX/temp/temp.spec/temp.explicit/p11.cpp b/test/CXX/temp/temp.spec/temp.explicit/p11.cpp new file mode 100644 index 0000000000..4ca5428315 --- /dev/null +++ b/test/CXX/temp/temp.spec/temp.explicit/p11.cpp @@ -0,0 +1,18 @@ +// RUN: %clang_cc1 -fsyntax-only -verify %s + +class X { + template class Y {}; +}; + +class A { + class B {}; + class C {}; +}; + +// C++0x [temp.explicit] 14.7.2/11: +// The usual access checking rules do not apply to names used to specify +// explicit instantiations. +template class X::Y; + +// As an extension, this rule is applied to explicit specializations as well. +template <> class X::Y {}; -- 2.40.0