[NFC] Add Incremental Info Bits to ModuleDecl

include/swift/AST/Decl.h

@@ -578,7 +578,7 @@ protected:
     HasAnyUnavailableValues : 1
   );
 
-  SWIFT_INLINE_BITFIELD(ModuleDecl, TypeDecl, 1+1+1+1+1+1+1+1+1,
+  SWIFT_INLINE_BITFIELD(ModuleDecl, TypeDecl, 1+1+1+1+1+1+1+1+1+1,
     /// If the module was or is being compiled with `-enable-testing`.
     TestingEnabled : 1,
 
@@ -607,7 +607,10 @@ protected:
     IsNonSwiftModule : 1,
 
     /// Whether this module is the main module.
-    IsMainModule : 1
+    IsMainModule : 1,
+
+    /// Whether this module has incremental dependency information available.
+    HasIncrementalInfo : 1
   );
 
   SWIFT_INLINE_BITFIELD(PrecedenceGroupDecl, Decl, 1+2,

include/swift/AST/Module.h

@@ -517,6 +517,12 @@ public:
     Bits.ModuleDecl.RawResilienceStrategy = unsigned(strategy);
   }
 
+  /// Returns true if this module was or is being compiled for testing.
+  bool hasIncrementalInfo() const { return Bits.ModuleDecl.HasIncrementalInfo; }
+  void setHasIncrementalInfo(bool enabled = true) {
+    Bits.ModuleDecl.HasIncrementalInfo = enabled;
+  }
+
   /// \returns true if this module is a system module; note that the StdLib is
   /// considered a system module.
   bool isSystemModule() const {

lib/AST/Module.cpp

@@ -484,6 +484,7 @@ ModuleDecl::ModuleDecl(Identifier name, ASTContext &ctx,
   Bits.ModuleDecl.IsSystemModule = 0;
   Bits.ModuleDecl.IsNonSwiftModule = 0;
   Bits.ModuleDecl.IsMainModule = 0;
+  Bits.ModuleDecl.HasIncrementalInfo = 0;
 }
 
 ArrayRef<ImplicitImport> ModuleDecl::getImplicitImports() const {