Generate IsReadOnlyAttribute on unsupported platforms.

src/Compiler/AbstractIL/il.fs

@@ -3274,6 +3274,9 @@ let destILArrTy ty =
 // Sigs of special types built-in
 // --------------------------------------------------------------------
 
+[<Literal>]
+let tname_Attribute = "System.Attribute"
+
 [<Literal>]
 let tname_Object = "System.Object"
 
@@ -3347,6 +3350,8 @@ type ILGlobals(primaryScopeRef: ILScopeRef, equivPrimaryAssemblyRefs: ILAssembly
 
     member x.primaryAssemblyName = x.primaryAssemblyRef.Name
 
+    member val typ_Attribute = mkILBoxedType (mkILNonGenericTySpec (mkSysILTypeRef tname_Attribute))
+
     member val typ_Object = mkILBoxedType (mkILNonGenericTySpec (mkSysILTypeRef tname_Object))
 
     member val typ_String = mkILBoxedType (mkILNonGenericTySpec (mkSysILTypeRef tname_String))

src/Compiler/AbstractIL/il.fsi

@@ -1815,6 +1815,7 @@ type internal ILGlobals =
     member primaryAssemblyScopeRef: ILScopeRef
     member primaryAssemblyRef: ILAssemblyRef
     member primaryAssemblyName: string
+    member typ_Attribute: ILType
     member typ_Object: ILType
     member typ_String: ILType
     member typ_Type: ILType

src/Compiler/CodeGen/IlxGen.fs

@@ -610,16 +610,10 @@ type PtrsOK =
     | PtrTypesNotOK
 
 let GenReadOnlyAttribute (g: TcGlobals) =
-    mkILCustomAttribute (g.attrib_IsReadOnlyAttribute.TypeRef, [], [], [])
+    g.AddEmbeddableSystemAttribute(g.attrib_IsReadOnlyAttribute.TypeRef, [], [], [])
 
 let GenReadOnlyAttributeIfNecessary (g: TcGlobals) ty =
-    let add =
-        false
-        && g.isSystem_Runtime_CompilerServices_IsReadOnlyAttributeAvailable
-        && isInByrefTy g ty
-        && g.attrib_IsReadOnlyAttribute.TyconRef.CanDeref
-
-    if add then
+    if isInByrefTy g ty then
         let attr = GenReadOnlyAttribute g
         Some attr
     else
@@ -2088,15 +2082,7 @@ type AnonTypeGenerationTable() =
             let ilMethods =
                 [
                     for propName, fldName, fldTy in flds ->
-                        let attrs =
-                            if
-                                false
-                                && g.isSystem_Runtime_CompilerServices_IsReadOnlyAttributeAvailable
-                                && isStruct
-                            then
-                                [ GenReadOnlyAttribute g ]
-                            else
-                                []
+                        let attrs = if isStruct then [ GenReadOnlyAttribute g ] else []
 
                         mkLdfldMethodDef ("get_" + propName, ILMemberAccess.Public, false, ilTy, fldName, fldTy, attrs)
                         |> g.AddMethodGeneratedAttributes
@@ -10897,12 +10883,7 @@ and GenTypeDef cenv mgbuf lazyInitInfo eenv m (tycon: Tycon) =
                             let isStruct = isStructTyconRef tcref
 
                             let attrs =
-                                if
-                                    false
-                                    && g.isSystem_Runtime_CompilerServices_IsReadOnlyAttributeAvailable
-                                    && isStruct
-                                    && not isStatic
-                                then
+                                if isStruct && not isStatic then
                                     [ GenReadOnlyAttribute g ]
                                 else
                                     []

src/Compiler/Driver/CompilerImports.fs

@@ -1163,7 +1163,7 @@ and [<Sealed>] TcImports
         | ResolvedCcu ccu -> Some ccu
         | UnresolvedCcu _ -> None
 
-    static let ccuHasType (ccu: CcuThunk) (nsname: string list) (tname: string) =
+    static let ccuHasType (ccu: CcuThunk) (nsname: string list) (tname: string) (publicOnly: bool) =
         let matchNameSpace (entityOpt: Entity option) n =
             match entityOpt with
             | None -> None
@@ -1172,7 +1172,14 @@ and [<Sealed>] TcImports
         match (Some ccu.Contents, nsname) ||> List.fold matchNameSpace with
         | Some ns ->
             match Map.tryFind tname ns.ModuleOrNamespaceType.TypesByMangledName with
-            | Some _ -> true
+            | Some e ->
+                if publicOnly then
+                    match e.TypeReprInfo with
+                    | TILObjectRepr data ->
+                        let (TILObjectReprData(_, _, tyDef)) = data
+                        tyDef.Access = ILTypeDefAccess.Public
+                    | _ -> false
+                else  true
             | None -> false
         | None -> false
 
@@ -2461,8 +2468,8 @@ and [<Sealed>] TcImports
                         ccu
                 |]
 
-            let tryFindSysTypeCcu path typeName =
-                sysCcus |> Array.tryFind (fun ccu -> ccuHasType ccu path typeName)
+            let tryFindSysTypeCcu path typeName publicOnly =
+                sysCcus |> Array.tryFind (fun ccu -> ccuHasType ccu path typeName publicOnly)
 
             let ilGlobals =
                 mkILGlobals (primaryScopeRef, equivPrimaryAssemblyRefs, fsharpCoreAssemblyScopeRef)

src/Compiler/Driver/CompilerOptions.fs

@@ -331,25 +331,25 @@ let ParseCompilerOptions (collectOtherArgument: string -> unit, blocks: Compiler
     let rec processArg args =
         match args with
         | [] -> ()
-        | rsp: string :: t when rsp.StartsWithOrdinal("@") ->
+        | opt: string :: t when opt.StartsWithOrdinal("@") ->
             let responseFileOptions =
                 let fullpath =
                     try
-                        Some(rsp.TrimStart('@') |> FileSystem.GetFullPathShim)
+                        Some(opt.TrimStart('@') |> FileSystem.GetFullPathShim)
                     with _ ->
                         None
 
                 match fullpath with
                 | None ->
-                    errorR (Error(FSComp.SR.optsResponseFileNameInvalid rsp, rangeCmdArgs))
+                    errorR (Error(FSComp.SR.optsResponseFileNameInvalid opt, rangeCmdArgs))
                     []
                 | Some path when not (FileSystem.FileExistsShim path) ->
-                    errorR (Error(FSComp.SR.optsResponseFileNotFound (rsp, path), rangeCmdArgs))
+                    errorR (Error(FSComp.SR.optsResponseFileNotFound (opt, path), rangeCmdArgs))
                     []
                 | Some path ->
                     match ResponseFile.parseFile path with
                     | Choice2Of2 _ ->
-                        errorR (Error(FSComp.SR.optsInvalidResponseFile (rsp, path), rangeCmdArgs))
+                        errorR (Error(FSComp.SR.optsInvalidResponseFile (opt, path), rangeCmdArgs))
                         []
                     | Choice1Of2 rspData ->
                         let onlyOptions l =

src/Compiler/Driver/CreateILModule.fs

@@ -286,7 +286,7 @@ module MainModuleBuilder =
         (
             ctok,
             tcConfig: TcConfig,
-            tcGlobals,
+            tcGlobals: TcGlobals,
             tcImports: TcImports,
             pdbfile,
             assemblyName,
@@ -304,8 +304,7 @@ module MainModuleBuilder =
         RequireCompilationThread ctok
 
         let ilTypeDefs =
-            //let topTypeDef = mkILTypeDefForGlobalFunctions tcGlobals.ilg (mkILMethods [], emptyILFields)
-            mkILTypeDefs codegenResults.ilTypeDefs
+            mkILTypeDefs (codegenResults.ilTypeDefs @ tcGlobals.embeddedTypeDefs)
 
         let mainModule =
             let hashAlg =