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//===--- SemaModule.cpp - Semantic Analysis for Modules -------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for modules (C++ modules syntax,
// Objective-C modules syntax, and Clang header modules).
//
//===----------------------------------------------------------------------===//
#include "clang/AST/ASTConsumer.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/SemaInternal.h"
using namespace clang;
using namespace sema;
static void checkModuleImportContext(Sema &S, Module *M,
SourceLocation ImportLoc, DeclContext *DC,
bool FromInclude = false) {
SourceLocation ExternCLoc;
if (auto *LSD = dyn_cast<LinkageSpecDecl>(DC)) {
switch (LSD->getLanguage()) {
case LinkageSpecDecl::lang_c:
if (ExternCLoc.isInvalid())
ExternCLoc = LSD->getBeginLoc();
break;
case LinkageSpecDecl::lang_cxx:
case LinkageSpecDecl::lang_cxx_11:
case LinkageSpecDecl::lang_cxx_14:
break;
}
DC = LSD->getParent();
}
while (isa<LinkageSpecDecl>(DC) || isa<ExportDecl>(DC))
DC = DC->getParent();
if (!isa<TranslationUnitDecl>(DC)) {
S.Diag(ImportLoc, (FromInclude && S.isModuleVisible(M))
? diag::ext_module_import_not_at_top_level_noop
: diag::err_module_import_not_at_top_level_fatal)
<< M->getFullModuleName() << DC;
S.Diag(cast<Decl>(DC)->getBeginLoc(),
diag::note_module_import_not_at_top_level)
<< DC;
} else if (!M->IsExternC && ExternCLoc.isValid()) {
S.Diag(ImportLoc, diag::ext_module_import_in_extern_c)
<< M->getFullModuleName();
S.Diag(ExternCLoc, diag::note_extern_c_begins_here);
}
}
Sema::DeclGroupPtrTy
Sema::ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc) {
if (!ModuleScopes.empty() &&
ModuleScopes.back().Module->Kind == Module::GlobalModuleFragment) {
// Under -std=c++2a -fmodules-ts, we can find an explicit 'module;' after
// already implicitly entering the global module fragment. That's OK.
assert(getLangOpts().CPlusPlusModules && getLangOpts().ModulesTS &&
"unexpectedly encountered multiple global module fragment decls");
ModuleScopes.back().BeginLoc = ModuleLoc;
return nullptr;
}
// We start in the global module; all those declarations are implicitly
// module-private (though they do not have module linkage).
auto &Map = PP.getHeaderSearchInfo().getModuleMap();
auto *GlobalModule = Map.createGlobalModuleFragmentForModuleUnit(ModuleLoc);
assert(GlobalModule && "module creation should not fail");
// Enter the scope of the global module.
ModuleScopes.push_back({});
ModuleScopes.back().BeginLoc = ModuleLoc;
ModuleScopes.back().Module = GlobalModule;
VisibleModules.setVisible(GlobalModule, ModuleLoc);
// All declarations created from now on are owned by the global module.
auto *TU = Context.getTranslationUnitDecl();
TU->setModuleOwnershipKind(Decl::ModuleOwnershipKind::Visible);
TU->setLocalOwningModule(GlobalModule);
// FIXME: Consider creating an explicit representation of this declaration.
return nullptr;
}
Sema::DeclGroupPtrTy
Sema::ActOnModuleDecl(SourceLocation StartLoc, SourceLocation ModuleLoc,
ModuleDeclKind MDK, ModuleIdPath Path, bool IsFirstDecl) {
assert((getLangOpts().ModulesTS || getLangOpts().CPlusPlusModules) &&
"should only have module decl in Modules TS or C++20");
// A module implementation unit requires that we are not compiling a module
// of any kind. A module interface unit requires that we are not compiling a
// module map.
switch (getLangOpts().getCompilingModule()) {
case LangOptions::CMK_None:
// It's OK to compile a module interface as a normal translation unit.
break;
case LangOptions::CMK_ModuleInterface:
if (MDK != ModuleDeclKind::Implementation)
break;
// We were asked to compile a module interface unit but this is a module
// implementation unit. That indicates the 'export' is missing.
Diag(ModuleLoc, diag::err_module_interface_implementation_mismatch)
<< FixItHint::CreateInsertion(ModuleLoc, "export ");
MDK = ModuleDeclKind::Interface;
break;
case LangOptions::CMK_ModuleMap:
Diag(ModuleLoc, diag::err_module_decl_in_module_map_module);
return nullptr;
case LangOptions::CMK_HeaderModule:
Diag(ModuleLoc, diag::err_module_decl_in_header_module);
return nullptr;
}
assert(ModuleScopes.size() <= 1 && "expected to be at global module scope");
// FIXME: Most of this work should be done by the preprocessor rather than
// here, in order to support macro import.
// Only one module-declaration is permitted per source file.
if (!ModuleScopes.empty() &&
ModuleScopes.back().Module->isModulePurview()) {
Diag(ModuleLoc, diag::err_module_redeclaration);
Diag(VisibleModules.getImportLoc(ModuleScopes.back().Module),
diag::note_prev_module_declaration);
return nullptr;
}
// Find the global module fragment we're adopting into this module, if any.
Module *GlobalModuleFragment = nullptr;
if (!ModuleScopes.empty() &&
ModuleScopes.back().Module->Kind == Module::GlobalModuleFragment)
GlobalModuleFragment = ModuleScopes.back().Module;
// In C++20, the module-declaration must be the first declaration if there
// is no global module fragment.
if (getLangOpts().CPlusPlusModules && !IsFirstDecl && !GlobalModuleFragment) {
Diag(ModuleLoc, diag::err_module_decl_not_at_start);
SourceLocation BeginLoc =
ModuleScopes.empty()
? SourceMgr.getLocForStartOfFile(SourceMgr.getMainFileID())
: ModuleScopes.back().BeginLoc;
if (BeginLoc.isValid()) {
Diag(BeginLoc, diag::note_global_module_introducer_missing)
<< FixItHint::CreateInsertion(BeginLoc, "module;\n");
}
}
// Flatten the dots in a module name. Unlike Clang's hierarchical module map
// modules, the dots here are just another character that can appear in a
// module name.
std::string ModuleName;
for (auto &Piece : Path) {
if (!ModuleName.empty())
ModuleName += ".";
ModuleName += Piece.first->getName();
}
// If a module name was explicitly specified on the command line, it must be
// correct.
if (!getLangOpts().CurrentModule.empty() &&
getLangOpts().CurrentModule != ModuleName) {
Diag(Path.front().second, diag::err_current_module_name_mismatch)
<< SourceRange(Path.front().second, Path.back().second)
<< getLangOpts().CurrentModule;
return nullptr;
}
const_cast<LangOptions&>(getLangOpts()).CurrentModule = ModuleName;
auto &Map = PP.getHeaderSearchInfo().getModuleMap();
Module *Mod;
switch (MDK) {
case ModuleDeclKind::Interface: {
// We can't have parsed or imported a definition of this module or parsed a
// module map defining it already.
if (auto *M = Map.findModule(ModuleName)) {
Diag(Path[0].second, diag::err_module_redefinition) << ModuleName;
if (M->DefinitionLoc.isValid())
Diag(M->DefinitionLoc, diag::note_prev_module_definition);
else if (const auto *FE = M->getASTFile())
Diag(M->DefinitionLoc, diag::note_prev_module_definition_from_ast_file)
<< FE->getName();
Mod = M;
break;
}
// Create a Module for the module that we're defining.
Mod = Map.createModuleForInterfaceUnit(ModuleLoc, ModuleName,
GlobalModuleFragment);
assert(Mod && "module creation should not fail");
break;
}
case ModuleDeclKind::Implementation:
std::pair<IdentifierInfo *, SourceLocation> ModuleNameLoc(
PP.getIdentifierInfo(ModuleName), Path[0].second);
Mod = getModuleLoader().loadModule(ModuleLoc, {ModuleNameLoc},
Module::AllVisible,
/*IsInclusionDirective=*/false);
if (!Mod) {
Diag(ModuleLoc, diag::err_module_not_defined) << ModuleName;
// Create an empty module interface unit for error recovery.
Mod = Map.createModuleForInterfaceUnit(ModuleLoc, ModuleName,
GlobalModuleFragment);
}
break;
}
if (!GlobalModuleFragment) {
ModuleScopes.push_back({});
if (getLangOpts().ModulesLocalVisibility)
ModuleScopes.back().OuterVisibleModules = std::move(VisibleModules);
} else {
// We're done with the global module fragment now.
ActOnEndOfTranslationUnitFragment(TUFragmentKind::Global);
}
// Switch from the global module fragment (if any) to the named module.
ModuleScopes.back().BeginLoc = StartLoc;
ModuleScopes.back().Module = Mod;
ModuleScopes.back().ModuleInterface = MDK != ModuleDeclKind::Implementation;
VisibleModules.setVisible(Mod, ModuleLoc);
// From now on, we have an owning module for all declarations we see.
// However, those declarations are module-private unless explicitly
// exported.
auto *TU = Context.getTranslationUnitDecl();
TU->setModuleOwnershipKind(Decl::ModuleOwnershipKind::ModulePrivate);
TU->setLocalOwningModule(Mod);
// FIXME: Create a ModuleDecl.
return nullptr;
}
Sema::DeclGroupPtrTy
Sema::ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
SourceLocation PrivateLoc) {
// C++20 [basic.link]/2:
// A private-module-fragment shall appear only in a primary module
// interface unit.
switch (ModuleScopes.empty() ? Module::GlobalModuleFragment
: ModuleScopes.back().Module->Kind) {
case Module::ModuleMapModule:
case Module::GlobalModuleFragment:
Diag(PrivateLoc, diag::err_private_module_fragment_not_module);
return nullptr;
case Module::PrivateModuleFragment:
Diag(PrivateLoc, diag::err_private_module_fragment_redefined);
Diag(ModuleScopes.back().BeginLoc, diag::note_previous_definition);
return nullptr;
case Module::ModuleInterfaceUnit:
break;
}
if (!ModuleScopes.back().ModuleInterface) {
Diag(PrivateLoc, diag::err_private_module_fragment_not_module_interface);
Diag(ModuleScopes.back().BeginLoc,
diag::note_not_module_interface_add_export)
<< FixItHint::CreateInsertion(ModuleScopes.back().BeginLoc, "export ");
return nullptr;
}
// FIXME: Check this isn't a module interface partition.
// FIXME: Check that this translation unit does not import any partitions;
// such imports would violate [basic.link]/2's "shall be the only module unit"
// restriction.
// We've finished the public fragment of the translation unit.
ActOnEndOfTranslationUnitFragment(TUFragmentKind::Normal);
auto &Map = PP.getHeaderSearchInfo().getModuleMap();
Module *PrivateModuleFragment =
Map.createPrivateModuleFragmentForInterfaceUnit(
ModuleScopes.back().Module, PrivateLoc);
assert(PrivateModuleFragment && "module creation should not fail");
// Enter the scope of the private module fragment.
ModuleScopes.push_back({});
ModuleScopes.back().BeginLoc = ModuleLoc;
ModuleScopes.back().Module = PrivateModuleFragment;
ModuleScopes.back().ModuleInterface = true;
VisibleModules.setVisible(PrivateModuleFragment, ModuleLoc);
// All declarations created from now on are scoped to the private module
// fragment (and are neither visible nor reachable in importers of the module
// interface).
auto *TU = Context.getTranslationUnitDecl();
TU->setModuleOwnershipKind(Decl::ModuleOwnershipKind::ModulePrivate);
TU->setLocalOwningModule(PrivateModuleFragment);
// FIXME: Consider creating an explicit representation of this declaration.
return nullptr;
}
DeclResult Sema::ActOnModuleImport(SourceLocation StartLoc,
SourceLocation ExportLoc,
SourceLocation ImportLoc,
ModuleIdPath Path) {
// Flatten the module path for a Modules TS module name.
std::pair<IdentifierInfo *, SourceLocation> ModuleNameLoc;
if (getLangOpts().ModulesTS) {
std::string ModuleName;
for (auto &Piece : Path) {
if (!ModuleName.empty())
ModuleName += ".";
ModuleName += Piece.first->getName();
}
ModuleNameLoc = {PP.getIdentifierInfo(ModuleName), Path[0].second};
Path = ModuleIdPath(ModuleNameLoc);
}
Module *Mod =
getModuleLoader().loadModule(ImportLoc, Path, Module::AllVisible,
/*IsInclusionDirective=*/false);
if (!Mod)
return true;
return ActOnModuleImport(StartLoc, ExportLoc, ImportLoc, Mod, Path);
}
/// Determine whether \p D is lexically within an export-declaration.
static const ExportDecl *getEnclosingExportDecl(const Decl *D) {
for (auto *DC = D->getLexicalDeclContext(); DC; DC = DC->getLexicalParent())
if (auto *ED = dyn_cast<ExportDecl>(DC))
return ED;
return nullptr;
}
DeclResult Sema::ActOnModuleImport(SourceLocation StartLoc,
SourceLocation ExportLoc,
SourceLocation ImportLoc,
Module *Mod, ModuleIdPath Path) {
VisibleModules.setVisible(Mod, ImportLoc);
checkModuleImportContext(*this, Mod, ImportLoc, CurContext);
// FIXME: we should support importing a submodule within a different submodule
// of the same top-level module. Until we do, make it an error rather than
// silently ignoring the import.
// Import-from-implementation is valid in the Modules TS. FIXME: Should we
// warn on a redundant import of the current module?
// FIXME: Import of a module from an implementation partition of the same
// module is permitted.
if (Mod->getTopLevelModuleName() == getLangOpts().CurrentModule &&
(getLangOpts().isCompilingModule() || !getLangOpts().ModulesTS)) {
Diag(ImportLoc, getLangOpts().isCompilingModule()
? diag::err_module_self_import
: diag::err_module_import_in_implementation)
<< Mod->getFullModuleName() << getLangOpts().CurrentModule;
}
SmallVector<SourceLocation, 2> IdentifierLocs;
Module *ModCheck = Mod;
for (unsigned I = 0, N = Path.size(); I != N; ++I) {
// If we've run out of module parents, just drop the remaining identifiers.
// We need the length to be consistent.
if (!ModCheck)
break;
ModCheck = ModCheck->Parent;
IdentifierLocs.push_back(Path[I].second);
}
// If this was a header import, pad out with dummy locations.
// FIXME: Pass in and use the location of the header-name token in this case.
if (Path.empty()) {
for (; ModCheck; ModCheck = ModCheck->Parent) {
IdentifierLocs.push_back(SourceLocation());
}
}
ImportDecl *Import = ImportDecl::Create(Context, CurContext, StartLoc,
Mod, IdentifierLocs);
CurContext->addDecl(Import);
// Sequence initialization of the imported module before that of the current
// module, if any.
if (!ModuleScopes.empty())
Context.addModuleInitializer(ModuleScopes.back().Module, Import);
// Re-export the module if needed.
if (!ModuleScopes.empty() && ModuleScopes.back().ModuleInterface) {
if (ExportLoc.isValid() || getEnclosingExportDecl(Import))
getCurrentModule()->Exports.emplace_back(Mod, false);
} else if (ExportLoc.isValid()) {
Diag(ExportLoc, diag::err_export_not_in_module_interface);
}
return Import;
}
void Sema::ActOnModuleInclude(SourceLocation DirectiveLoc, Module *Mod) {
checkModuleImportContext(*this, Mod, DirectiveLoc, CurContext, true);
BuildModuleInclude(DirectiveLoc, Mod);
}
void Sema::BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod) {
// Determine whether we're in the #include buffer for a module. The #includes
// in that buffer do not qualify as module imports; they're just an
// implementation detail of us building the module.
//
// FIXME: Should we even get ActOnModuleInclude calls for those?
bool IsInModuleIncludes =
TUKind == TU_Module &&
getSourceManager().isWrittenInMainFile(DirectiveLoc);
bool ShouldAddImport = !IsInModuleIncludes;
// If this module import was due to an inclusion directive, create an
// implicit import declaration to capture it in the AST.
if (ShouldAddImport) {
TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
DirectiveLoc, Mod,
DirectiveLoc);
if (!ModuleScopes.empty())
Context.addModuleInitializer(ModuleScopes.back().Module, ImportD);
TU->addDecl(ImportD);
Consumer.HandleImplicitImportDecl(ImportD);
}
getModuleLoader().makeModuleVisible(Mod, Module::AllVisible, DirectiveLoc);
VisibleModules.setVisible(Mod, DirectiveLoc);
}
void Sema::ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod) {
checkModuleImportContext(*this, Mod, DirectiveLoc, CurContext, true);
ModuleScopes.push_back({});
ModuleScopes.back().Module = Mod;
if (getLangOpts().ModulesLocalVisibility)
ModuleScopes.back().OuterVisibleModules = std::move(VisibleModules);
VisibleModules.setVisible(Mod, DirectiveLoc);
// The enclosing context is now part of this module.
// FIXME: Consider creating a child DeclContext to hold the entities
// lexically within the module.
if (getLangOpts().trackLocalOwningModule()) {
for (auto *DC = CurContext; DC; DC = DC->getLexicalParent()) {
cast<Decl>(DC)->setModuleOwnershipKind(
getLangOpts().ModulesLocalVisibility
? Decl::ModuleOwnershipKind::VisibleWhenImported
: Decl::ModuleOwnershipKind::Visible);
cast<Decl>(DC)->setLocalOwningModule(Mod);
}
}
}
void Sema::ActOnModuleEnd(SourceLocation EomLoc, Module *Mod) {
if (getLangOpts().ModulesLocalVisibility) {
VisibleModules = std::move(ModuleScopes.back().OuterVisibleModules);
// Leaving a module hides namespace names, so our visible namespace cache
// is now out of date.
VisibleNamespaceCache.clear();
}
assert(!ModuleScopes.empty() && ModuleScopes.back().Module == Mod &&
"left the wrong module scope");
ModuleScopes.pop_back();
// We got to the end of processing a local module. Create an
// ImportDecl as we would for an imported module.
FileID File = getSourceManager().getFileID(EomLoc);
SourceLocation DirectiveLoc;
if (EomLoc == getSourceManager().getLocForEndOfFile(File)) {
// We reached the end of a #included module header. Use the #include loc.
assert(File != getSourceManager().getMainFileID() &&
"end of submodule in main source file");
DirectiveLoc = getSourceManager().getIncludeLoc(File);
} else {
// We reached an EOM pragma. Use the pragma location.
DirectiveLoc = EomLoc;
}
BuildModuleInclude(DirectiveLoc, Mod);
// Any further declarations are in whatever module we returned to.
if (getLangOpts().trackLocalOwningModule()) {
// The parser guarantees that this is the same context that we entered
// the module within.
for (auto *DC = CurContext; DC; DC = DC->getLexicalParent()) {
cast<Decl>(DC)->setLocalOwningModule(getCurrentModule());
if (!getCurrentModule())
cast<Decl>(DC)->setModuleOwnershipKind(
Decl::ModuleOwnershipKind::Unowned);
}
}
}
void Sema::createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
Module *Mod) {
// Bail if we're not allowed to implicitly import a module here.
if (isSFINAEContext() || !getLangOpts().ModulesErrorRecovery ||
VisibleModules.isVisible(Mod))
return;
// Create the implicit import declaration.
TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
Loc, Mod, Loc);
TU->addDecl(ImportD);
Consumer.HandleImplicitImportDecl(ImportD);
// Make the module visible.
getModuleLoader().makeModuleVisible(Mod, Module::AllVisible, Loc);
VisibleModules.setVisible(Mod, Loc);
}
/// We have parsed the start of an export declaration, including the '{'
/// (if present).
Decl *Sema::ActOnStartExportDecl(Scope *S, SourceLocation ExportLoc,
SourceLocation LBraceLoc) {
ExportDecl *D = ExportDecl::Create(Context, CurContext, ExportLoc);
// Set this temporarily so we know the export-declaration was braced.
D->setRBraceLoc(LBraceLoc);
// C++2a [module.interface]p1:
// An export-declaration shall appear only [...] in the purview of a module
// interface unit. An export-declaration shall not appear directly or
// indirectly within [...] a private-module-fragment.
if (ModuleScopes.empty() || !ModuleScopes.back().Module->isModulePurview()) {
Diag(ExportLoc, diag::err_export_not_in_module_interface) << 0;
} else if (!ModuleScopes.back().ModuleInterface) {
Diag(ExportLoc, diag::err_export_not_in_module_interface) << 1;
Diag(ModuleScopes.back().BeginLoc,
diag::note_not_module_interface_add_export)
<< FixItHint::CreateInsertion(ModuleScopes.back().BeginLoc, "export ");
} else if (ModuleScopes.back().Module->Kind ==
Module::PrivateModuleFragment) {
Diag(ExportLoc, diag::err_export_in_private_module_fragment);
Diag(ModuleScopes.back().BeginLoc, diag::note_private_module_fragment);
}
for (const DeclContext *DC = CurContext; DC; DC = DC->getLexicalParent()) {
if (const auto *ND = dyn_cast<NamespaceDecl>(DC)) {
// An export-declaration shall not appear directly or indirectly within
// an unnamed namespace [...]
if (ND->isAnonymousNamespace()) {
Diag(ExportLoc, diag::err_export_within_anonymous_namespace);
Diag(ND->getLocation(), diag::note_anonymous_namespace);
// Don't diagnose internal-linkage declarations in this region.
D->setInvalidDecl();
break;
}
// A declaration is exported if it is [...] a namespace-definition
// that contains an exported declaration.
//
// Defer exporting the namespace until after we leave it, in order to
// avoid marking all subsequent declarations in the namespace as exported.
if (!DeferredExportedNamespaces.insert(ND).second)
break;
}
}
// [...] its declaration or declaration-seq shall not contain an
// export-declaration.
if (auto *ED = getEnclosingExportDecl(D)) {
Diag(ExportLoc, diag::err_export_within_export);
if (ED->hasBraces())
Diag(ED->getLocation(), diag::note_export);
}
CurContext->addDecl(D);
PushDeclContext(S, D);
D->setModuleOwnershipKind(Decl::ModuleOwnershipKind::VisibleWhenImported);
return D;
}
static bool checkExportedDeclContext(Sema &S, DeclContext *DC,
SourceLocation BlockStart);
namespace {
enum class UnnamedDeclKind {
Empty,
StaticAssert,
Asm,
UsingDirective,
Context
};
}
static llvm::Optional<UnnamedDeclKind> getUnnamedDeclKind(Decl *D) {
if (isa<EmptyDecl>(D))
return UnnamedDeclKind::Empty;
if (isa<StaticAssertDecl>(D))
return UnnamedDeclKind::StaticAssert;
if (isa<FileScopeAsmDecl>(D))
return UnnamedDeclKind::Asm;
if (isa<UsingDirectiveDecl>(D))
return UnnamedDeclKind::UsingDirective;
// Everything else either introduces one or more names or is ill-formed.
return llvm::None;
}
unsigned getUnnamedDeclDiag(UnnamedDeclKind UDK, bool InBlock) {
switch (UDK) {
case UnnamedDeclKind::Empty:
case UnnamedDeclKind::StaticAssert:
// Allow empty-declarations and static_asserts in an export block as an
// extension.
return InBlock ? diag::ext_export_no_name_block : diag::err_export_no_name;
case UnnamedDeclKind::UsingDirective:
// Allow exporting using-directives as an extension.
return diag::ext_export_using_directive;
case UnnamedDeclKind::Context:
// Allow exporting DeclContexts that transitively contain no declarations
// as an extension.
return diag::ext_export_no_names;
case UnnamedDeclKind::Asm:
return diag::err_export_no_name;
}
llvm_unreachable("unknown kind");
}
static void diagExportedUnnamedDecl(Sema &S, UnnamedDeclKind UDK, Decl *D,
SourceLocation BlockStart) {
S.Diag(D->getLocation(), getUnnamedDeclDiag(UDK, BlockStart.isValid()))
<< (unsigned)UDK;
if (BlockStart.isValid())
S.Diag(BlockStart, diag::note_export);
}
/// Check that it's valid to export \p D.
static bool checkExportedDecl(Sema &S, Decl *D, SourceLocation BlockStart) {
// C++2a [module.interface]p3:
// An exported declaration shall declare at least one name
if (auto UDK = getUnnamedDeclKind(D))
diagExportedUnnamedDecl(S, *UDK, D, BlockStart);
// [...] shall not declare a name with internal linkage.
if (auto *ND = dyn_cast<NamedDecl>(D)) {
// Don't diagnose anonymous union objects; we'll diagnose their members
// instead.
if (ND->getDeclName() && ND->getFormalLinkage() == InternalLinkage) {
S.Diag(ND->getLocation(), diag::err_export_internal) << ND;
if (BlockStart.isValid())
S.Diag(BlockStart, diag::note_export);
}
}
// C++2a [module.interface]p5:
// all entities to which all of the using-declarators ultimately refer
// shall have been introduced with a name having external linkage
if (auto *USD = dyn_cast<UsingShadowDecl>(D)) {
NamedDecl *Target = USD->getUnderlyingDecl();
if (Target->getFormalLinkage() == InternalLinkage) {
S.Diag(USD->getLocation(), diag::err_export_using_internal) << Target;
S.Diag(Target->getLocation(), diag::note_using_decl_target);
if (BlockStart.isValid())
S.Diag(BlockStart, diag::note_export);
}
}
// Recurse into namespace-scope DeclContexts. (Only namespace-scope
// declarations are exported.)
if (auto *DC = dyn_cast<DeclContext>(D))
if (DC->getRedeclContext()->isFileContext() && !isa<EnumDecl>(D))
return checkExportedDeclContext(S, DC, BlockStart);
return false;
}
/// Check that it's valid to export all the declarations in \p DC.
static bool checkExportedDeclContext(Sema &S, DeclContext *DC,
SourceLocation BlockStart) {
bool AllUnnamed = true;
for (auto *D : DC->decls())
AllUnnamed &= checkExportedDecl(S, D, BlockStart);
return AllUnnamed;
}
/// Complete the definition of an export declaration.
Decl *Sema::ActOnFinishExportDecl(Scope *S, Decl *D, SourceLocation RBraceLoc) {
auto *ED = cast<ExportDecl>(D);
if (RBraceLoc.isValid())
ED->setRBraceLoc(RBraceLoc);
PopDeclContext();
if (!D->isInvalidDecl()) {
SourceLocation BlockStart =
ED->hasBraces() ? ED->getBeginLoc() : SourceLocation();
for (auto *Child : ED->decls()) {
if (checkExportedDecl(*this, Child, BlockStart)) {
// If a top-level child is a linkage-spec declaration, it might contain
// no declarations (transitively), in which case it's ill-formed.
diagExportedUnnamedDecl(*this, UnnamedDeclKind::Context, Child,
BlockStart);
}
}
}
return D;
}