[Modules TS] Diagnose attempts to enter module implementation units without the module interface being available.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@315381 91177308-0d34-0410-b5e6-96231b3b80d8

Author: zygoloid

include/clang/Basic/DiagnosticSemaKinds.td

@@ -8994,6 +8994,9 @@ def err_module_redefinition : Error<
   "redefinition of module '%0'">;
 def note_prev_module_definition : Note<"previously defined here">;
 def note_prev_module_definition_from_ast_file : Note<"module loaded from '%0'">;
+def err_module_not_defined : Error<
+  "definition of module '%0' is not available; use -fmodule-file= to specify "
+  "path to precompiled module interface">;
 def err_module_private_specialization : Error<
   "%select{template|partial|member}0 specialization cannot be "
   "declared __module_private__">;

include/clang/Sema/Sema.h

@@ -1533,7 +1533,8 @@ class Sema {
                                TypeDiagnoser *Diagnoser);
 
   struct ModuleScope {
-    clang::Module *Module;
+    clang::Module *Module = nullptr;
+    bool ModuleInterface = false;
     VisibleModuleSet OuterVisibleModules;
   };
   /// The modules we're currently parsing.
@@ -2051,9 +2052,9 @@ class Sema {
                               SourceLocation SemiLoc);
 
   enum class ModuleDeclKind {
-    Module,         ///< 'module X;'
+    Interface,      ///< 'export module X;'
+    Implementation, ///< 'module X;'
     Partition,      ///< 'module partition X;'
-    Implementation, ///< 'module implementation X;'
   };
 
   /// The parser has processed a module-declaration that begins the definition

lib/Parse/Parser.cpp

@@ -2048,7 +2048,7 @@ Parser::DeclGroupPtrTy Parser::ParseModuleDecl() {
   SourceLocation StartLoc = Tok.getLocation();
 
   Sema::ModuleDeclKind MDK = TryConsumeToken(tok::kw_export)
-                                 ? Sema::ModuleDeclKind::Module
+                                 ? Sema::ModuleDeclKind::Interface
                                  : Sema::ModuleDeclKind::Implementation;
 
   assert(Tok.is(tok::kw_module) && "not a module declaration");
@@ -2057,7 +2057,7 @@ Parser::DeclGroupPtrTy Parser::ParseModuleDecl() {
   if (Tok.is(tok::identifier) && NextToken().is(tok::identifier) &&
       Tok.getIdentifierInfo()->isStr("partition")) {
     // If 'partition' is present, this must be a module interface unit.
-    if (MDK != Sema::ModuleDeclKind::Module)
+    if (MDK != Sema::ModuleDeclKind::Interface)
       Diag(Tok.getLocation(), diag::err_module_implementation_partition)
         << FixItHint::CreateInsertion(ModuleLoc, "export ");
     MDK = Sema::ModuleDeclKind::Partition;

lib/Sema/SemaDecl.cpp

@@ -16168,6 +16168,7 @@ Sema::DeclGroupPtrTy Sema::ActOnModuleDecl(SourceLocation StartLoc,
     // 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:
@@ -16207,7 +16208,7 @@ Sema::DeclGroupPtrTy Sema::ActOnModuleDecl(SourceLocation StartLoc,
   assert(ModuleScopes.size() == 1 && "expected to be at global module scope");
 
   switch (MDK) {
-  case ModuleDeclKind::Module: {
+  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)) {
@@ -16237,14 +16238,16 @@ Sema::DeclGroupPtrTy Sema::ActOnModuleDecl(SourceLocation StartLoc,
         PP.getIdentifierInfo(ModuleName), Path[0].second);
     Mod = getModuleLoader().loadModule(ModuleLoc, Path, Module::AllVisible,
                                        /*IsIncludeDirective=*/false);
-    // FIXME: Produce an error in this case.
-    if (!Mod)
+    if (!Mod) {
+      Diag(ModuleLoc, diag::err_module_not_defined) << ModuleName;
       return nullptr;
+    }
     break;
   }
 
   // Switch from the global module to the named module.
   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.
@@ -16430,8 +16433,7 @@ Decl *Sema::ActOnStartExportDecl(Scope *S, SourceLocation ExportLoc,
   // C++ Modules TS draft:
   //   An export-declaration shall appear in the purview of a module other than
   //   the global module.
-  if (ModuleScopes.empty() ||
-      ModuleScopes.back().Module->Kind != Module::ModuleInterfaceUnit)
+  if (ModuleScopes.empty() || !ModuleScopes.back().ModuleInterface)
     Diag(ExportLoc, diag::err_export_not_in_module_interface);
 
   //   An export-declaration [...] shall not contain more than one

test/CXX/modules-ts/basic/basic.link/module-declaration.cpp

@@ -9,7 +9,6 @@
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -emit-module-interface -fmodule-file=%t/x.pcm %t/x.y.cppm -o %t/x.y.pcm
 //
 // Module implementation for unknown and known module. (The former is ill-formed.)
-// FIXME: TEST=1 should fail because we don't have an interface for module z.
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -verify %s \
 // RUN:            -DTEST=1 -DEXPORT= -DPARTITION= -DMODULE_NAME=z
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -verify %s \
@@ -32,11 +31,11 @@
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -verify %s \
 // RUN:            -DTEST=7 -DEXPORT= -DPARTITION=elderberry -DMODULE_NAME=z
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -verify %s \
-// RUN:            -DTEST=8 -DEXPORT= -DPARTITION= -DMODULE_NAME='z [[]]'
+// RUN:            -DTEST=8 -DEXPORT=export -DPARTITION= -DMODULE_NAME='z [[]]'
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -verify %s \
-// RUN:            -DTEST=9 -DEXPORT= -DPARTITION= -DMODULE_NAME='z [[fancy]]'
+// RUN:            -DTEST=9 -DEXPORT=export -DPARTITION= -DMODULE_NAME='z [[fancy]]'
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -verify %s \
-// RUN:            -DTEST=10 -DEXPORT= -DPARTITION= -DMODULE_NAME='z [[maybe_unused]]'
+// RUN:            -DTEST=10 -DEXPORT=export -DPARTITION= -DMODULE_NAME='z [[maybe_unused]]'
 
 EXPORT module PARTITION MODULE_NAME;
 #if TEST == 4
@@ -45,11 +44,13 @@ EXPORT module PARTITION MODULE_NAME;
 #elif TEST == 6
 // expected-error@-5 {{module partition must be declared 'export'}}
 #elif TEST == 7
-// expected-error@-7 {{expected ';'}} expected-error@-7 {{requires a type specifier}}
+// expected-error@-7 {{expected ';'}} expected-error@-7 {{requires a type specifier}} expected-error@-7 {{definition of module 'elderberry' is not available}}
 #elif TEST == 9
 // expected-warning@-9 {{unknown attribute 'fancy' ignored}}
 #elif TEST == 10
 // expected-error-re@-11 {{'maybe_unused' attribute cannot be applied to a module{{$}}}}
+#elif TEST == 1
+// expected-error@-13 {{definition of module 'z' is not available}}
 #else
 // expected-no-diagnostics
 #endif

test/CXX/modules-ts/dcl.dcl/dcl.module/dcl.module.import/p1.cpp

@@ -9,12 +9,15 @@
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -emit-module-interface %t/a.b.cppm -o %t/a.b.pcm
 //
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -fmodule-file=%t/a.b.pcm -verify %s \
-// RUN:            -DMODULE_NAME=z
+// RUN:            -DMODULE_NAME=z -DINTERFACE
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -fmodule-file=%t/a.b.pcm -verify %s \
 // RUN:            -DMODULE_NAME=a.b
 // RUN: %clang_cc1 -std=c++1z -fmodules-ts -I%t -fmodule-file=%t/x.y.pcm -fmodule-file=%t/a.b.pcm -verify %s \
 // RUN:            -DMODULE_X -DMODULE_NAME=x
 
+#ifdef INTERFACE
+export
+#endif
 module MODULE_NAME;
 
 int use_1 = a;

test/CXX/modules-ts/dcl.dcl/dcl.module/dcl.module.interface/p1.cpp

@@ -1,27 +1,28 @@
 // RUN: %clang_cc1 -fmodules-ts %s -verify -o /dev/null
-// RUN: %clang_cc1 -fmodules-ts %s -DINTERFACE -verify -o /dev/null
-// RUN: %clang_cc1 -fmodules-ts %s -DIMPLEMENTATION -verify -o /dev/null
+// RUN: %clang_cc1 -fmodules-ts %s -DINTERFACE -verify -emit-module-interface -o %t
+// RUN: %clang_cc1 -fmodules-ts %s -DIMPLEMENTATION -verify -fmodule-file=%t -o /dev/null
 //
 // RUN: %clang_cc1 -fmodules-ts %s -DBUILT_AS_INTERFACE -emit-module-interface -verify -o /dev/null
 // RUN: %clang_cc1 -fmodules-ts %s -DINTERFACE -DBUILT_AS_INTERFACE -emit-module-interface -verify -o /dev/null
 // RUN: %clang_cc1 -fmodules-ts %s -DIMPLEMENTATION -DBUILT_AS_INTERFACE -emit-module-interface -verify -o /dev/null
 
 #if INTERFACE
+// expected-no-diagnostics
 export module A;
 #elif IMPLEMENTATION
 module A;
  #ifdef BUILT_AS_INTERFACE
   // expected-error@-2 {{missing 'export' specifier in module declaration while building module interface}}
+  #define INTERFACE
  #endif
 #else
  #ifdef BUILT_AS_INTERFACE
   // FIXME: Diagnose missing module declaration (at end of TU)
  #endif
 #endif
 
-export int a;
 #ifndef INTERFACE
-// expected-error@-2 {{export declaration can only be used within a module interface unit}}
+export int b; // expected-error {{export declaration can only be used within a module interface unit}}
 #else
-// expected-no-diagnostics
+export int a;
 #endif

test/CXX/modules-ts/dcl.dcl/dcl.module/p2.cpp

@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -fmodules-ts -verify %s
+
+// A named module shall contain exactly one module interface unit.
+module M; // expected-error {{definition of module 'M' is not available; use -fmodule-file= to specify path to precompiled module interface}}
+
+// FIXME: How do we ensure there is not more than one?