Consistently create a new declaration when merging a pre-existing but
hidden definition with a would-be-parsed redefinition.
This permits a bunch of cleanups. In particular, we no longer need to
take merged definitions into account when checking declaration
visibility, only when checking definition visibility, which makes
certain visibility checks take linear instead of quadratic time.
We could also now remove the UPD_DECL_EXPORTED update record and track
on each declaration whether it was demoted from a definition (as we
already do for variables), but I'm not doing that in this patch to keep
the changes here simpler.
llvm-svn: 342018
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 496d06c..f1e9286 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12706,6 +12706,7 @@
Definition->getDescribedFunctionTemplate() ||
Definition->getNumTemplateParameterLists())) {
SkipBody->ShouldSkip = true;
+ SkipBody->Previous = const_cast<FunctionDecl*>(Definition);
if (auto *TD = Definition->getDescribedFunctionTemplate())
makeMergedDefinitionVisible(TD);
makeMergedDefinitionVisible(const_cast<FunctionDecl*>(Definition));
@@ -14034,7 +14035,7 @@
// many points during the parsing of a struct declaration (because
// the #pragma tokens are effectively skipped over during the
// parsing of the struct).
- if (TUK == TUK_Definition) {
+ if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
AddAlignmentAttributesForRecord(RD);
AddMsStructLayoutForRecord(RD);
}
@@ -14465,12 +14466,15 @@
// comparison.
SkipBody->CheckSameAsPrevious = true;
SkipBody->New = createTagFromNewDecl();
- SkipBody->Previous = Hidden;
+ SkipBody->Previous = Def;
+ return Def;
} else {
SkipBody->ShouldSkip = true;
+ SkipBody->Previous = Def;
makeMergedDefinitionVisible(Hidden);
+ // Carry on and handle it like a normal definition. We'll
+ // skip starting the definitiion later.
}
- return Def;
} else if (!IsExplicitSpecializationAfterInstantiation) {
// A redeclaration in function prototype scope in C isn't
// visible elsewhere, so merely issue a warning.
@@ -14699,7 +14703,7 @@
// many points during the parsing of a struct declaration (because
// the #pragma tokens are effectively skipped over during the
// parsing of the struct).
- if (TUK == TUK_Definition) {
+ if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
AddAlignmentAttributesForRecord(RD);
AddMsStructLayoutForRecord(RD);
}
@@ -14761,7 +14765,7 @@
if (PrevDecl)
CheckRedeclarationModuleOwnership(New, PrevDecl);
- if (TUK == TUK_Definition)
+ if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
New->startDefinition();
ProcessDeclAttributeList(S, New, Attrs);
@@ -14811,6 +14815,8 @@
if (auto RD = dyn_cast<RecordDecl>(New))
RD->completeDefinition();
return nullptr;
+ } else if (SkipBody && SkipBody->ShouldSkip) {
+ return SkipBody->Previous;
} else {
return New;
}
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 37a5b7b..fd0f487 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -10496,7 +10496,8 @@
OldDecl->getTemplateParameters(),
/*Complain=*/true,
TPL_TemplateMatch))
- OldTemplateParams = OldDecl->getTemplateParameters();
+ OldTemplateParams =
+ OldDecl->getMostRecentDecl()->getTemplateParameters();
else
Invalid = true;
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 8cf8dae..f7f5957 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -1392,8 +1392,17 @@
return LookupModulesCache;
}
+/// Determine whether the module M is part of the current module from the
+/// perspective of a module-private visibility check.
+static bool isInCurrentModule(const Module *M, const LangOptions &LangOpts) {
+ // If M is the global module fragment of a module that we've not yet finished
+ // parsing, then it must be part of the current module.
+ return M->getTopLevelModuleName() == LangOpts.CurrentModule ||
+ (M->Kind == Module::GlobalModuleFragment && !M->Parent);
+}
+
bool Sema::hasVisibleMergedDefinition(NamedDecl *Def) {
- for (Module *Merged : Context.getModulesWithMergedDefinition(Def))
+ for (const Module *Merged : Context.getModulesWithMergedDefinition(Def))
if (isModuleVisible(Merged))
return true;
return false;
@@ -1407,8 +1416,8 @@
if (Def->getModuleOwnershipKind() == Decl::ModuleOwnershipKind::Visible &&
getLangOpts().ModulesLocalVisibility)
return true;
- for (Module *Merged : Context.getModulesWithMergedDefinition(Def))
- if (Merged->getTopLevelModuleName() == getLangOpts().CurrentModule)
+ for (const Module *Merged : Context.getModulesWithMergedDefinition(Def))
+ if (isInCurrentModule(Merged, getLangOpts()))
return true;
return false;
}
@@ -1428,8 +1437,6 @@
if (!DefaultArg.isInherited() && Modules) {
auto *NonConstD = const_cast<ParmDecl*>(D);
Modules->push_back(S.getOwningModule(NonConstD));
- const auto &Merged = S.Context.getModulesWithMergedDefinition(NonConstD);
- Modules->insert(Modules->end(), Merged.begin(), Merged.end());
}
// If there was a previous default argument, maybe its parameter is visible.
@@ -1464,11 +1471,8 @@
HasFilteredRedecls = true;
- if (Modules) {
+ if (Modules)
Modules->push_back(R->getOwningModule());
- const auto &Merged = S.Context.getModulesWithMergedDefinition(R);
- Modules->insert(Modules->end(), Merged.begin(), Merged.end());
- }
}
// Only return false if there is at least one redecl that is not filtered out.
@@ -1519,27 +1523,11 @@
assert(D->isHidden() && "should not call this: not in slow case");
Module *DeclModule = SemaRef.getOwningModule(D);
- if (!DeclModule) {
- // A module-private declaration with no owning module means this is in the
- // global module in the C++ Modules TS. This is visible within the same
- // translation unit only.
- // FIXME: Don't assume that "same translation unit" means the same thing
- // as "not from an AST file".
- assert(D->isModulePrivate() && "hidden decl has no module");
- if (!D->isFromASTFile() || SemaRef.hasMergedDefinitionInCurrentModule(D))
- return true;
- } else {
- // If the owning module is visible, and the decl is not module private,
- // then the decl is visible too. (Module private is ignored within the same
- // top-level module.)
- if (D->isModulePrivate()
- ? DeclModule->getTopLevelModuleName() ==
- SemaRef.getLangOpts().CurrentModule ||
- SemaRef.hasMergedDefinitionInCurrentModule(D)
- : SemaRef.isModuleVisible(DeclModule) ||
- SemaRef.hasVisibleMergedDefinition(D))
- return true;
- }
+ assert(DeclModule && "hidden decl has no owning module");
+
+ // If the owning module is visible, the decl is visible.
+ if (SemaRef.isModuleVisible(DeclModule, D->isModulePrivate()))
+ return true;
// Determine whether a decl context is a file context for the purpose of
// visibility. This looks through some (export and linkage spec) transparent
@@ -1589,29 +1577,41 @@
return VisibleWithinParent;
}
- // FIXME: All uses of DeclModule below this point should also check merged
- // modules.
- if (!DeclModule)
- return false;
+ return false;
+}
+
+bool Sema::isModuleVisible(const Module *M, bool ModulePrivate) {
+ // The module might be ordinarily visible. For a module-private query, that
+ // means it is part of the current module. For any other query, that means it
+ // is in our visible module set.
+ if (ModulePrivate) {
+ if (isInCurrentModule(M, getLangOpts()))
+ return true;
+ } else {
+ if (VisibleModules.isVisible(M))
+ return true;
+ }
+
+ // Otherwise, it might be visible by virtue of the query being within a
+ // template instantiation or similar that is permitted to look inside M.
// Find the extra places where we need to look.
- const auto &LookupModules = SemaRef.getLookupModules();
+ const auto &LookupModules = getLookupModules();
if (LookupModules.empty())
return false;
- // If our lookup set contains the decl's module, it's visible.
- if (LookupModules.count(DeclModule))
+ // If our lookup set contains the module, it's visible.
+ if (LookupModules.count(M))
return true;
- // If the declaration isn't exported, it's not visible in any other module.
- if (D->isModulePrivate())
+ // For a module-private query, that's everywhere we get to look.
+ if (ModulePrivate)
return false;
- // Check whether DeclModule is transitively exported to an import of
- // the lookup set.
+ // Check whether M is transitively exported to an import of the lookup set.
return std::any_of(LookupModules.begin(), LookupModules.end(),
- [&](const Module *M) {
- return M->isModuleVisible(DeclModule); });
+ [&](const Module *LookupM) {
+ return LookupM->isModuleVisible(M); });
}
bool Sema::isVisibleSlow(const NamedDecl *D) {
@@ -5061,12 +5061,12 @@
if (!Def)
Def = Decl;
- Module *Owner = getOwningModule(Decl);
+ Module *Owner = getOwningModule(Def);
assert(Owner && "definition of hidden declaration is not in a module");
llvm::SmallVector<Module*, 8> OwningModules;
OwningModules.push_back(Owner);
- auto Merged = Context.getModulesWithMergedDefinition(Decl);
+ auto Merged = Context.getModulesWithMergedDefinition(Def);
OwningModules.insert(OwningModules.end(), Merged.begin(), Merged.end());
diagnoseMissingImport(Loc, Decl, Decl->getLocation(), OwningModules, MIK,
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index c826b83..61e51de 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -1487,19 +1487,19 @@
NamedDecl *Hidden = nullptr;
if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
SkipBody->ShouldSkip = true;
+ SkipBody->Previous = Def;
auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
assert(Tmpl && "original definition of a class template is not a "
"class template?");
makeMergedDefinitionVisible(Hidden);
makeMergedDefinitionVisible(Tmpl);
- return Def;
+ } else {
+ Diag(NameLoc, diag::err_redefinition) << Name;
+ Diag(Def->getLocation(), diag::note_previous_definition);
+ // FIXME: Would it make sense to try to "forget" the previous
+ // definition, as part of error recovery?
+ return true;
}
-
- Diag(NameLoc, diag::err_redefinition) << Name;
- Diag(Def->getLocation(), diag::note_previous_definition);
- // FIXME: Would it make sense to try to "forget" the previous
- // definition, as part of error recovery?
- return true;
}
}
} else if (PrevDecl) {
@@ -1520,13 +1520,14 @@
if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
CheckTemplateParameterList(
TemplateParams,
- PrevClassTemplate ? PrevClassTemplate->getTemplateParameters()
- : nullptr,
+ PrevClassTemplate
+ ? PrevClassTemplate->getMostRecentDecl()->getTemplateParameters()
+ : nullptr,
(SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
SemanticContext->isDependentContext())
? TPC_ClassTemplateMember
- : TUK == TUK_Friend ? TPC_FriendClassTemplate
- : TPC_ClassTemplate))
+ : TUK == TUK_Friend ? TPC_FriendClassTemplate : TPC_ClassTemplate,
+ SkipBody))
Invalid = true;
if (SS.isSet()) {
@@ -1561,7 +1562,7 @@
// Add alignment attributes if necessary; these attributes are checked when
// the ASTContext lays out the structure.
- if (TUK == TUK_Definition) {
+ if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
AddAlignmentAttributesForRecord(NewClass);
AddMsStructLayoutForRecord(NewClass);
}
@@ -1604,7 +1605,7 @@
NewClass->setLexicalDeclContext(CurContext);
NewTemplate->setLexicalDeclContext(CurContext);
- if (TUK == TUK_Definition)
+ if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
NewClass->startDefinition();
ProcessDeclAttributeList(S, NewClass, Attr);
@@ -1653,6 +1654,9 @@
ActOnDocumentableDecl(NewTemplate);
+ if (SkipBody && SkipBody->ShouldSkip)
+ return SkipBody->Previous;
+
return NewTemplate;
}
@@ -2150,10 +2154,17 @@
/// \param TPC Describes the context in which we are checking the given
/// template parameter list.
///
+/// \param SkipBody If we might have already made a prior merged definition
+/// of this template visible, the corresponding body-skipping information.
+/// Default argument redefinition is not an error when skipping such a body,
+/// because (under the ODR) we can assume the default arguments are the same
+/// as the prior merged definition.
+///
/// \returns true if an error occurred, false otherwise.
bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
TemplateParameterList *OldParams,
- TemplateParamListContext TPC) {
+ TemplateParamListContext TPC,
+ SkipBodyInfo *SkipBody) {
bool Invalid = false;
// C++ [temp.param]p10:
@@ -2203,7 +2214,8 @@
"Parameter packs can't have a default argument!");
SawParameterPack = true;
} else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
- NewTypeParm->hasDefaultArgument()) {
+ NewTypeParm->hasDefaultArgument() &&
+ (!SkipBody || !SkipBody->ShouldSkip)) {
OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
SawDefaultArgument = true;
@@ -2247,7 +2259,8 @@
if (!NewNonTypeParm->isPackExpansion())
SawParameterPack = true;
} else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
- NewNonTypeParm->hasDefaultArgument()) {
+ NewNonTypeParm->hasDefaultArgument() &&
+ (!SkipBody || !SkipBody->ShouldSkip)) {
OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
SawDefaultArgument = true;
@@ -2290,7 +2303,8 @@
SawParameterPack = true;
} else if (OldTemplateParm &&
hasVisibleDefaultArgument(OldTemplateParm) &&
- NewTemplateParm->hasDefaultArgument()) {
+ NewTemplateParm->hasDefaultArgument() &&
+ (!SkipBody || !SkipBody->ShouldSkip)) {
OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
SawDefaultArgument = true;
@@ -7689,9 +7703,8 @@
NamedDecl *Hidden = nullptr;
if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
SkipBody->ShouldSkip = true;
+ SkipBody->Previous = Def;
makeMergedDefinitionVisible(Hidden);
- // From here on out, treat this as just a redeclaration.
- TUK = TUK_Declaration;
} else if (Def) {
SourceRange Range(TemplateNameLoc, RAngleLoc);
Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
@@ -7705,7 +7718,7 @@
// Add alignment attributes if necessary; these attributes are checked when
// the ASTContext lays out the structure.
- if (TUK == TUK_Definition) {
+ if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
AddAlignmentAttributesForRecord(Specialization);
AddMsStructLayoutForRecord(Specialization);
}
@@ -7741,7 +7754,7 @@
Specialization->setLexicalDeclContext(CurContext);
// We may be starting the definition of this specialization.
- if (TUK == TUK_Definition)
+ if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
Specialization->startDefinition();
if (TUK == TUK_Friend) {
@@ -7757,6 +7770,10 @@
// context. However, specializations are not found by name lookup.
CurContext->addDecl(Specialization);
}
+
+ if (SkipBody && SkipBody->ShouldSkip)
+ return SkipBody->Previous;
+
return Specialization;
}
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 3ed9eee..2c29b8c 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1228,7 +1228,7 @@
}
TemplateParameterList *PrevParams
- = PrevClassTemplate->getTemplateParameters();
+ = PrevClassTemplate->getMostRecentDecl()->getTemplateParameters();
// Make sure the parameter lists match.
if (!SemaRef.TemplateParameterListsAreEqual(InstParams, PrevParams,
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 5fefac6..900ccb1 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -7615,14 +7615,28 @@
assert(D && "missing definition for pattern of instantiated definition");
*Suggested = D;
- if (isVisible(D))
+
+ auto DefinitionIsVisible = [&] {
+ // The (primary) definition might be in a visible module.
+ if (isVisible(D))
+ return true;
+
+ // A visible module might have a merged definition instead.
+ if (D->isModulePrivate() ? hasMergedDefinitionInCurrentModule(D)
+ : hasVisibleMergedDefinition(D))
+ return true;
+
+ return false;
+ };
+
+ if (DefinitionIsVisible())
return true;
// The external source may have additional definitions of this entity that are
// visible, so complete the redeclaration chain now and ask again.
if (auto *Source = Context.getExternalSource()) {
Source->CompleteRedeclChain(D);
- return isVisible(D);
+ return DefinitionIsVisible();
}
return false;