1 files changed, 124 insertions, 43 deletions

diff --git a/lib/Lex/Pragma.cpp b/lib/Lex/Pragma.cpp
index 576151a98b..51da2baac9 100644
--- a/lib/Lex/Pragma.cpp
+++ b/lib/Lex/Pragma.cpp
@@ -534,47 +534,6 @@ void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
   }
 }
 
-void Preprocessor::HandlePragmaModuleImport(Token &ImportTok) {
-  SourceLocation ImportLoc = ImportTok.getLocation();
-
-  Token Tok;
-
-  llvm::SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 8> ModuleName;
-  while (true) {
-    LexUnexpandedToken(Tok);
-    if (Tok.isNot(tok::identifier)) {
-      Diag(Tok.getLocation(),
-           diag::err_pragma_module_import_expected_module_name) << 0;
-      return;
-    }
-
-    ModuleName.emplace_back(Tok.getIdentifierInfo(), Tok.getLocation());
-
-    LexUnexpandedToken(Tok);
-    assert(Tok.isNot(tok::eof));
-    if (Tok.is(tok::eod))
-      break;
-    if (Tok.isNot(tok::period)) {
-      Diag(Tok.getLocation(),
-           diag::err_pragma_module_import_expected_module_name) << 1;
-      return;
-    }
-  }
-
-  // If we have a non-empty module path, load the named module.
-  Module *Imported =
-      TheModuleLoader.loadModule(ImportLoc, ModuleName, Module::Hidden,
-                                 /*IsIncludeDirective=*/false);
-  if (!Imported)
-    return;
-
-  makeModuleVisible(Imported, ImportLoc);
-  EnterAnnotationToken(SourceRange(ImportLoc, Tok.getLocation()),
-                       tok::annot_module_include, Imported);
-  if (Callbacks)
-    Callbacks->moduleImport(ImportLoc, ModuleName, Imported);
-}
-
 /// ParsePragmaPushOrPopMacro - Handle parsing of pragma push_macro/pop_macro.
 /// Return the IdentifierInfo* associated with the macro to push or pop.
 IdentifierInfo *Preprocessor::ParsePragmaPushOrPopMacro(Token &Tok) {
@@ -1342,6 +1301,26 @@ public:
   }
 };
 
+static bool LexModuleName(
+    Preprocessor &PP, Token &Tok,
+    llvm::SmallVectorImpl<std::pair<IdentifierInfo *, SourceLocation>>
+        &ModuleName) {
+  while (true) {
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::identifier)) {
+      PP.Diag(Tok.getLocation(), diag::err_pp_expected_module_name)
+        << ModuleName.empty();
+      return true;
+    }
+
+    ModuleName.emplace_back(Tok.getIdentifierInfo(), Tok.getLocation());
+
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::period))
+      return false;
+  }
+}
+
 /// Handle the clang \#pragma module import extension. The syntax is:
 /// \code
 ///   #pragma clang module import some.module.name
@@ -1350,8 +1329,108 @@ struct PragmaModuleImportHandler : public PragmaHandler {
   PragmaModuleImportHandler() : PragmaHandler("import") {}
 
   void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
-                    Token &ImportTok) override {
-    PP.HandlePragmaModuleImport(ImportTok);
+                    Token &Tok) override {
+    SourceLocation ImportLoc = Tok.getLocation();
+
+    // Read the module name.
+    llvm::SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 8>
+        ModuleName;
+    if (LexModuleName(PP, Tok, ModuleName))
+      return;
+
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    // If we have a non-empty module path, load the named module.
+    Module *Imported =
+        PP.getModuleLoader().loadModule(ImportLoc, ModuleName, Module::Hidden,
+                                      /*IsIncludeDirective=*/false);
+    if (!Imported)
+      return;
+
+    PP.makeModuleVisible(Imported, ImportLoc);
+    PP.EnterAnnotationToken(SourceRange(ImportLoc, ModuleName.back().second),
+                            tok::annot_module_include, Imported);
+    if (auto *CB = PP.getPPCallbacks())
+      CB->moduleImport(ImportLoc, ModuleName, Imported);
+  }
+};
+
+/// Handle the clang \#pragma module begin extension. The syntax is:
+/// \code
+///   #pragma clang module begin some.module.name
+///   ...
+///   #pragma clang module end
+/// \endcode
+struct PragmaModuleBeginHandler : public PragmaHandler {
+  PragmaModuleBeginHandler() : PragmaHandler("begin") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                    Token &Tok) override {
+    SourceLocation BeginLoc = Tok.getLocation();
+
+    // Read the module name.
+    llvm::SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 8>
+        ModuleName;
+    if (LexModuleName(PP, Tok, ModuleName))
+      return;
+
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    // We can only enter submodules of the current module.
+    StringRef Current = PP.getLangOpts().CurrentModule;
+    if (ModuleName.front().first->getName() != Current) {
+      PP.Diag(ModuleName.front().second, diag::err_pp_module_begin_wrong_module)
+        << ModuleName.front().first << (ModuleName.size() > 1)
+        << Current.empty() << Current;
+      return;
+    }
+
+    // Find the module we're entering. We require that a module map for it
+    // be loaded or implicitly loadable.
+    // FIXME: We could create the submodule here. We'd need to know whether
+    // it's supposed to be explicit, but not much else.
+    Module *M = PP.getHeaderSearchInfo().getModuleMap().findModule(Current);
+    if (!M) {
+      PP.Diag(ModuleName.front().second,
+              diag::err_pp_module_begin_no_module_map) << Current;
+      return;
+    }
+    for (unsigned I = 1; I != ModuleName.size(); ++I) {
+      auto *NewM = M->findSubmodule(ModuleName[I].first->getName());
+      if (!NewM) {
+        PP.Diag(ModuleName[I].second, diag::err_pp_module_begin_no_submodule)
+          << M->getFullModuleName() << ModuleName[I].first;
+        return;
+      }
+      M = NewM;
+    }
+
+    // Enter the scope of the submodule.
+    PP.EnterSubmodule(M, BeginLoc, /*ForPragma*/true);
+    PP.EnterAnnotationToken(SourceRange(BeginLoc, ModuleName.back().second),
+                            tok::annot_module_begin, M);
+  }
+};
+
+/// Handle the clang \#pragma module end extension.
+struct PragmaModuleEndHandler : public PragmaHandler {
+  PragmaModuleEndHandler() : PragmaHandler("end") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                    Token &Tok) override {
+    SourceLocation Loc = Tok.getLocation();
+
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    Module *M = PP.LeaveSubmodule(/*ForPragma*/true);
+    if (M)
+      PP.EnterAnnotationToken(SourceRange(Loc), tok::annot_module_end, M);
+    else
+      PP.Diag(Loc, diag::err_pp_module_end_without_module_begin);
   }
 };
 
@@ -1582,6 +1661,8 @@ void Preprocessor::RegisterBuiltinPragmas() {
   auto *ModuleHandler = new PragmaNamespace("module");
   AddPragmaHandler("clang", ModuleHandler);
   ModuleHandler->AddPragma(new PragmaModuleImportHandler());
+  ModuleHandler->AddPragma(new PragmaModuleBeginHandler());
+  ModuleHandler->AddPragma(new PragmaModuleEndHandler());
 
   AddPragmaHandler("STDC", new PragmaSTDC_FENV_ACCESSHandler());
   AddPragmaHandler("STDC", new PragmaSTDC_CX_LIMITED_RANGEHandler());