Fix modules codegen to be compatible with modules-ts

The Module::WithCodegen flag was only being set when the module was
parsed from a ModuleMap. Instead set it late, in the ASTWriter to match
the layer where the MODULAR_CODEGEN_DECLs list is determined (the
WithCodegen flag essentially means "are this module's decls in
MODULAR_CODEGEN_DECLs").

When simultaneous emission of AST file and modular object is implemented
this may need to change - the Module::WithCodegen flag will need to be
set earlier, and ideally the MODULAR_CODEGEN_DECLs gathering will
consult this flag (that's not possible right now since Decls destined
for an AST File don't have a Module - only if they're /read/ from a
Module is that true - I expect that would need to change as well).

llvm-svn: 293692
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 1db5bec..384e570 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -1501,7 +1501,6 @@
       (!ActiveModule->Parent && ModuleName == "Darwin"))
     ActiveModule->NoUndeclaredIncludes = true;
   ActiveModule->Directory = Directory;
-  ActiveModule->WithCodegen = L.getLangOpts().ModularCodegen;
 
   if (!ActiveModule->Parent) {
     StringRef MapFileName(ModuleMapFile->getName());
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index cfd4c38..1f5ef42 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -2590,7 +2590,7 @@
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InferExplicit...
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // InferExportWild...
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ConfigMacrosExh...
-  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // WithCodegen
+  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // WithCodegen
   Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // Name
   unsigned DefinitionAbbrev = Stream.EmitAbbrev(std::move(Abbrev));
 
@@ -2690,7 +2690,7 @@
                                          Mod->InferExplicitSubmodules,
                                          Mod->InferExportWildcard,
                                          Mod->ConfigMacrosExhaustive,
-                                         Mod->WithCodegen};
+                                         Context->getLangOpts().ModularCodegen && WritingModule};
       Stream.EmitRecordWithBlob(DefinitionAbbrev, Record, Mod->Name);
     }
 
diff --git a/clang/test/CodeGenCXX/modules-ts.cppm b/clang/test/CodeGenCXX/modules-ts.cppm
index da3bcb2..90f6b53 100644
--- a/clang/test/CodeGenCXX/modules-ts.cppm
+++ b/clang/test/CodeGenCXX/modules-ts.cppm
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fmodules-ts -std=c++1z -triple=x86_64-linux-gnu -emit-module-interface %s -o %t.pcm
+// RUN: %clang_cc1 -fmodules-ts -std=c++1z -triple=x86_64-linux-gnu -fmodules-codegen -emit-module-interface %s -o %t.pcm
 // RUN: %clang_cc1 -fmodules-ts -std=c++1z -triple=x86_64-linux-gnu %t.pcm -emit-llvm -o - | FileCheck %s
 
 module FooBar;
@@ -8,6 +8,9 @@
   int f() { return 0; }
 }
 
+// CHECK-LABEL: define weak_odr void @_Z2f2v(
+inline void f2() { }
+
 // FIXME: Emit global variables and their initializers with this TU.
 // Emit an initialization function that other TUs can call, with guard variable.