r315402 - [modules] Only take visible using-directives into account during name lookup.
Vassil Vassilev via cfe-commits
cfe-commits at lists.llvm.org
Mon Oct 30 15:43:32 PDT 2017
On 30/10/17 23:40, Richard Smith wrote:
> On 30 October 2017 at 15:12, Vassil Vassilev via cfe-commits
> <cfe-commits at lists.llvm.org <mailto:cfe-commits at lists.llvm.org>> wrote:
>
> On 11/10/17 03:19, Richard Smith via cfe-commits wrote:
>
> Author: rsmith
> Date: Tue Oct 10 18:19:11 2017
> New Revision: 315402
>
> URL: http://llvm.org/viewvc/llvm-project?rev=315402&view=rev
> <http://llvm.org/viewvc/llvm-project?rev=315402&view=rev>
> Log:
> [modules] Only take visible using-directives into account
> during name lookup.
>
> Added:
> cfe/trunk/test/Modules/using-directive.cpp
> Modified:
> cfe/trunk/lib/Sema/SemaLookup.cpp
>
> Modified: cfe/trunk/lib/Sema/SemaLookup.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLookup.cpp?rev=315402&r1=315401&r2=315402&view=diff
> <http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLookup.cpp?rev=315402&r1=315401&r2=315402&view=diff>
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaLookup.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaLookup.cpp Tue Oct 10 18:19:11 2017
> @@ -88,13 +88,15 @@ namespace {
> /// A collection of using directives, as used by C++
> unqualified
> /// lookup.
> class UnqualUsingDirectiveSet {
> + Sema &SemaRef;
> +
> typedef SmallVector<UnqualUsingEntry, 8> ListTy;
> ListTy list;
> llvm::SmallPtrSet<DeclContext*, 8> visited;
> public:
> - UnqualUsingDirectiveSet() {}
> + UnqualUsingDirectiveSet(Sema &SemaRef) : SemaRef(SemaRef) {}
> void visitScopeChain(Scope *S, Scope
> *InnermostFileScope) {
> // C++ [namespace.udir]p1:
> @@ -113,7 +115,8 @@ namespace {
> visit(Ctx, Ctx);
> } else if (!Ctx || Ctx->isFunctionOrMethod()) {
> for (auto *I : S->using_directives())
> - visit(I, InnermostFileDC);
> + if (SemaRef.isVisible(I))
> + visit(I, InnermostFileDC);
> }
> }
> }
> @@ -152,7 +155,7 @@ namespace {
> while (true) {
> for (auto UD : DC->using_directives()) {
> DeclContext *NS = UD->getNominatedNamespace();
> - if (visited.insert(NS).second) {
> + if (visited.insert(NS).second &&
> SemaRef.isVisible(UD)) {
>
> It looks like this change breaks examples such as:
>
> // RUN: rm -fr %t
> // RUN %clang_cc1 -fmodules -fmodules-local-submodule-visibility
> -fmodules-cache-path=%t -verify %s
> // expected-no-diagnostics
> #pragma clang module build M
> module M { module TDFNodes {} module TDFInterface {} }
> #pragma clang module contents
> // TDFNodes
> #pragma clang module begin M.TDFNodes
> namespace Detail {
> namespace TDF {
> class TLoopManager {};
> }
> }
> namespace Internal {
> namespace TDF {
> using namespace Detail::TDF;
> }
> }
> #pragma clang module end
>
> // TDFInterface
> #pragma clang module begin M.TDFInterface
> #pragma clang module import M.TDFNodes
> namespace Internal {
> namespace TDF {
> using namespace Detail::TDF;
> }
> }
> #pragma clang module end
>
> #pragma clang module endbuild
>
> #pragma clang module import M.TDFNodes
> namespace Internal {
> namespace TDF {
> TLoopManager * use;
> }
> }
>
> I suspect that it triggers a preexisting bug in failing to make
> M.TDFNodes visible...
>
>
> This code in NamedDecl::declarationReplaces is wrong, we even have a
> FIXME for the bug:
>
> // UsingDirectiveDecl's are not really NamedDecl's, and all have
> same name.
> // They can be replaced if they nominate the same namespace.
> // FIXME: Is this true even if they have different module visibility?
> if (auto *UD = dyn_cast<UsingDirectiveDecl>(this))
> return UD->getNominatedNamespace()->getOriginalNamespace() ==
> cast<UsingDirectiveDecl>(OldD)->getNominatedNamespace()
> ->getOriginalNamespace();
>
> Fixed in r316965 by deleting the above code :)
You ninjaed me I just understood that the getOriginalNamespace was wrong
and hunting that down :D
Thanks for the quick fix!
>
> This might introduce a performance regression in the presence of large
> numbers of duplicated using-directives. We can rectify that, if
> needed, by making using-directives redeclarable, but I'm not expecting
> that to be a problem outside of pathological cases.
>
> addUsingDirective(UD, EffectiveDC);
> queue.push_back(NS);
> }
> @@ -1085,7 +1088,7 @@ bool Sema::CppLookupName(LookupResult &R
> // }
> // }
> //
> - UnqualUsingDirectiveSet UDirs;
> + UnqualUsingDirectiveSet UDirs(*this);
> bool VisitedUsingDirectives = false;
> bool LeftStartingScope = false;
> DeclContext *OutsideOfTemplateParamDC = nullptr;
> @@ -1868,22 +1871,19 @@ static bool LookupQualifiedNameInUsingDi
> DeclContext *StartDC) {
> assert(StartDC->isFileContext() && "start context is not a
> file context");
> - DeclContext::udir_range UsingDirectives =
> StartDC->using_directives();
> - if (UsingDirectives.begin() == UsingDirectives.end())
> return false;
> + // We have not yet looked into these namespaces, much less
> added
> + // their "using-children" to the queue.
> + SmallVector<NamespaceDecl*, 8> Queue;
> // We have at least added all these contexts to the queue.
> llvm::SmallPtrSet<DeclContext*, 8> Visited;
> Visited.insert(StartDC);
> - // We have not yet looked into these namespaces, much
> less added
> - // their "using-children" to the queue.
> - SmallVector<NamespaceDecl*, 8> Queue;
> -
> // We have already looked into the initial namespace; seed
> the queue
> // with its using-children.
> - for (auto *I : UsingDirectives) {
> + for (auto *I : StartDC->using_directives()) {
> NamespaceDecl *ND =
> I->getNominatedNamespace()->getOriginalNamespace();
> - if (Visited.insert(ND).second)
> + if (Visited.insert(ND).second && S.isVisible(I))
> Queue.push_back(ND);
> }
> @@ -1931,7 +1931,7 @@ static bool LookupQualifiedNameInUsingDi
> for (auto I : ND->using_directives()) {
> NamespaceDecl *Nom = I->getNominatedNamespace();
> - if (Visited.insert(Nom).second)
> + if (Visited.insert(Nom).second && S.isVisible(I))
> Queue.push_back(Nom);
> }
> }
> @@ -3540,6 +3540,8 @@ static void LookupVisibleDecls(DeclConte
> if (QualifiedNameLookup) {
> ShadowContextRAII Shadow(Visited);
> for (auto I : Ctx->using_directives()) {
> + if (!Result.getSema().isVisible(I))
> + continue;
> LookupVisibleDecls(I->getNominatedNamespace(), Result,
> QualifiedNameLookup, InBaseClass,
> Consumer, Visited,
> IncludeDependentBases);
> @@ -3746,7 +3748,7 @@ void Sema::LookupVisibleDecls(Scope *S,
> // Determine the set of using directives available during
> // unqualified name lookup.
> Scope *Initial = S;
> - UnqualUsingDirectiveSet UDirs;
> + UnqualUsingDirectiveSet UDirs(*this);
> if (getLangOpts().CPlusPlus) {
> // Find the first namespace or translation-unit scope.
> while (S && !isNamespaceOrTranslationUnitScope(S))
>
> Added: cfe/trunk/test/Modules/using-directive.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/using-directive.cpp?rev=315402&view=auto
> <http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/using-directive.cpp?rev=315402&view=auto>
> ==============================================================================
> --- cfe/trunk/test/Modules/using-directive.cpp (added)
> +++ cfe/trunk/test/Modules/using-directive.cpp Tue Oct 10
> 18:19:11 2017
> @@ -0,0 +1,62 @@
> +// RUN: %clang_cc1 -fmodules
> -fmodules-local-submodule-visibility
> -fno-modules-error-recovery -fno-spell-checking -verify %s
> +
> +#pragma clang module build a
> +module a { explicit module b {} explicit module c {} }
> +#pragma clang module contents
> +
> +#pragma clang module begin a.b
> +namespace b { int n; }
> +#pragma clang module end
> +
> +#pragma clang module begin a.c
> +#pragma clang module import a.b
> +namespace c { using namespace b; }
> +#pragma clang module end
> +
> +#pragma clang module begin a
> +#pragma clang module import a.c
> +using namespace c;
> +#pragma clang module end
> +
> +#pragma clang module endbuild
> +
> +#pragma clang module import a.b
> +void use1() {
> + (void)n; // expected-error {{use of undeclared identifier}}
> + (void)::n; // expected-error {{no member named 'n' in the
> global namespace}}
> + (void)b::n;
> +}
> +namespace b {
> + void use1_in_b() { (void)n; }
> +}
> +namespace c {
> + void use1_in_c() { (void)n; } // expected-error {{use of
> undeclared identifier}}
> +}
> +
> +#pragma clang module import a.c
> +void use2() {
> + (void)n; // expected-error {{use of undeclared identifier}}
> + (void)::n; // expected-error {{no member named 'n' in the
> global namespace}}
> + (void)b::n;
> + (void)c::n;
> +}
> +namespace b {
> + void use2_in_b() { (void)n; }
> +}
> +namespace c {
> + void use2_in_c() { (void)n; }
> +}
> +
> +#pragma clang module import a
> +void use3() {
> + (void)n;
> + (void)::n;
> + (void)b::n;
> + (void)c::n;
> +}
> +namespace b {
> + void use3_in_b() { (void)n; }
> +}
> +namespace c {
> + void use3_in_c() { (void)n; }
> +}
>
>
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