r315402 - [modules] Only take visible using-directives into account during name lookup.
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Mon Oct 30 15:40:12 PDT 2017
On 30 October 2017 at 15:12, Vassil Vassilev via cfe-commits <
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
>> 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/SemaL
>> ookup.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 :)
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()->ge
>> tOriginalNamespace();
>> - 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
>> ============================================================
>> ==================
>> --- 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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>
>
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