[c++2a] Implement semantic restrictions for 'export' declarations.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@358932 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 26 insertions, 5 deletions

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 2c914fee72..dc7d5657e9 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -4239,8 +4239,10 @@ public:
   SourceLocation getRBraceLoc() const { return RBraceLoc; }
   void setRBraceLoc(SourceLocation L) { RBraceLoc = L; }
 
+  bool hasBraces() const { return RBraceLoc.isValid(); }
+
   SourceLocation getEndLoc() const LLVM_READONLY {
-    if (RBraceLoc.isValid())
+    if (hasBraces())
       return RBraceLoc;
     // No braces: get the end location of the (only) declaration in context
     // (if present).
diff --git a/include/clang/AST/DeclBase.h b/include/clang/AST/DeclBase.h
index 9fa9f00800..64adf304c6 100644
--- a/include/clang/AST/DeclBase.h
+++ b/include/clang/AST/DeclBase.h
@@ -600,10 +600,6 @@ public:
     return getModuleOwnershipKind() == ModuleOwnershipKind::ModulePrivate;
   }
 
-  /// Whether this declaration is exported (by virtue of being lexically
-  /// within an ExportDecl or by being a NamespaceDecl).
-  bool isExported() const;
-
   /// Return true if this declaration has an attribute which acts as
   /// definition of the entity, such as 'alias' or 'ifunc'.
   bool hasDefiningAttr() const;
diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index d11bf58acd..d46f82f2a5 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -168,6 +168,7 @@ def ExtraTokens : DiagGroup<"extra-tokens">;
 def CXX98CompatExtraSemi : DiagGroup<"c++98-compat-extra-semi">;
 def CXX11ExtraSemi : DiagGroup<"c++11-extra-semi">;
 def EmptyInitStatement : DiagGroup<"empty-init-stmt">;
+def ExportUnnamed : DiagGroup<"export-unnamed">;
 def ExtraSemiStmt : DiagGroup<"extra-semi-stmt", [EmptyInitStatement]>;
 def ExtraSemi : DiagGroup<"extra-semi", [CXX98CompatExtraSemi,
                                          CXX11ExtraSemi]>;
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index f8aef6f627..a44c682471 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9273,8 +9273,27 @@ def err_module_decl_not_at_start : Error<
 def note_global_module_introducer_missing : Note<
   "add 'module;' to the start of the file to introduce a "
   "global module fragment">;
+def err_export_within_anonymous_namespace : Error<
+  "export declaration appears within anonymous namespace">;
+def note_anonymous_namespace : Note<"anonymous namespace begins here">;
+def ext_export_no_name_block : ExtWarn<
+  "ISO C++20 does not permit %select{an empty|a static_assert}0 declaration "
+  "to appear in an export block">, InGroup<ExportUnnamed>;
+def ext_export_no_names : ExtWarn<
+  "ISO C++20 does not permit a declaration that does not introduce any names "
+  "to be exported">, InGroup<ExportUnnamed>;
+def note_export : Note<"export block begins here">;
+def err_export_no_name : Error<
+  "%select{empty|static_assert|asm}0 declaration cannot be exported">;
+def ext_export_using_directive : ExtWarn<
+  "ISO C++20 does not permit using directive to be exported">,
+  InGroup<DiagGroup<"export-using-directive">>;
 def err_export_within_export : Error<
   "export declaration appears within another export declaration">;
+def err_export_internal : Error<
+  "declaration of %0 with internal linkage cannot be exported">;
+def err_export_using_internal : Error<
+  "using declaration referring to %0 with internal linkage cannot be exported">;
 def err_export_not_in_module_interface : Error<
   "export declaration can only be used within a module interface unit"
   "%select{ after the module declaration|}0">;
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index a2f43118df..1a5c756f90 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1651,6 +1651,9 @@ private:
   /// The modules we're currently parsing.
   llvm::SmallVector<ModuleScope, 16> ModuleScopes;
 
+  /// Namespace definitions that we will export when they finish.
+  llvm::SmallPtrSet<const NamespaceDecl*, 8> DeferredExportedNamespaces;
+
   /// Get the module whose scope we are currently within.
   Module *getCurrentModule() const {
     return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;