Cache attributes read by compiler— replace repeated string matching with O(1) enum lookups

src/Compiler/AbstractIL/il.fs

@@ -1229,19 +1229,75 @@ type ILAttributes(array: ILAttribute[]) =
 
     static member val internal Empty = ILAttributes([||])
 
-[<NoEquality; NoComparison>]
-type ILAttributesStored =
-
-    /// Computed by ilread.fs based on metadata index
+[<Flags>]
+type WellKnownILAttributes =
+    | None = 0u
+    | IsReadOnlyAttribute = (1u <<< 0)
+    | IsUnmanagedAttribute = (1u <<< 1)
+    | IsByRefLikeAttribute = (1u <<< 2)
+    | ExtensionAttribute = (1u <<< 3)
+    | NullableAttribute = (1u <<< 4)
+    | ParamArrayAttribute = (1u <<< 5)
+    | AllowNullLiteralAttribute = (1u <<< 6)
+    | ReflectedDefinitionAttribute = (1u <<< 7)
+    | AutoOpenAttribute = (1u <<< 8)
+    | InternalsVisibleToAttribute = (1u <<< 9)
+    | CallerMemberNameAttribute = (1u <<< 10)
+    | CallerFilePathAttribute = (1u <<< 11)
+    | CallerLineNumberAttribute = (1u <<< 12)
+    | IDispatchConstantAttribute = (1u <<< 13)
+    | IUnknownConstantAttribute = (1u <<< 14)
+    | RequiresLocationAttribute = (1u <<< 15)
+    | SetsRequiredMembersAttribute = (1u <<< 16)
+    | NoEagerConstraintApplicationAttribute = (1u <<< 17)
+    | DefaultMemberAttribute = (1u <<< 18)
+    | ObsoleteAttribute = (1u <<< 19)
+    | CompilerFeatureRequiredAttribute = (1u <<< 20)
+    | ExperimentalAttribute = (1u <<< 21)
+    | RequiredMemberAttribute = (1u <<< 22)
+    | NullableContextAttribute = (1u <<< 23)
+    | AttributeUsageAttribute = (1u <<< 24)
+    | NotComputed = (1u <<< 31)
+
+type internal ILAttributesStoredRepr =
     | Reader of (int32 -> ILAttribute[])
-
-    /// Already computed
     | Given of ILAttributes
 
-    member x.GetCustomAttrs metadataIndex =
-        match x with
-        | Reader f -> ILAttributes(f metadataIndex)
-        | Given attrs -> attrs
+[<Sealed; NoEquality; NoComparison>]
+type ILAttributesStored private (metadataIndex: int32, initial: ILAttributesStoredRepr) =
+    [<VolatileField>]
+    let mutable repr = initial
+
+    [<VolatileField>]
+    let mutable wellKnownFlags = WellKnownILAttributes.NotComputed
+
+    member _.MetadataIndex = metadataIndex
+
+    member x.CustomAttrs: ILAttributes =
+        match repr with
+        | Given a -> a
+        | Reader f ->
+            let r = ILAttributes(f metadataIndex)
+            repr <- Given r
+            r
+
+    member x.HasWellKnownAttribute(flag: WellKnownILAttributes, compute: ILAttributes -> WellKnownILAttributes) : bool =
+        x.GetOrComputeWellKnownFlags(compute) &&& flag <> WellKnownILAttributes.None
+
+    member x.GetOrComputeWellKnownFlags(compute: ILAttributes -> WellKnownILAttributes) : WellKnownILAttributes =
+        let f = wellKnownFlags
+
+        if f <> WellKnownILAttributes.NotComputed then
+            f
+        else
+            let a = x.CustomAttrs
+            let computed = compute a
+            wellKnownFlags <- computed
+            computed
+
+    static member CreateReader(idx: int32, f: int32 -> ILAttribute[]) = ILAttributesStored(idx, Reader f)
+
+    static member CreateGiven(attrs: ILAttributes) = ILAttributesStored(-1, Given attrs)
 
 let emptyILCustomAttrs = ILAttributes [||]
 
@@ -1256,18 +1312,18 @@ let mkILCustomAttrs l =
     | [] -> emptyILCustomAttrs
     | _ -> mkILCustomAttrsFromArray (List.toArray l)
 
-let emptyILCustomAttrsStored = ILAttributesStored.Given emptyILCustomAttrs
+let emptyILCustomAttrsStored = ILAttributesStored.CreateGiven emptyILCustomAttrs
 
 let storeILCustomAttrs (attrs: ILAttributes) =
     if attrs.AsArray().Length = 0 then
         emptyILCustomAttrsStored
     else
-        ILAttributesStored.Given attrs
+        ILAttributesStored.CreateGiven attrs
 
 let mkILCustomAttrsComputed f =
-    ILAttributesStored.Reader(fun _ -> f ())
+    ILAttributesStored.CreateReader(-1, fun _ -> f ())
 
-let mkILCustomAttrsReader f = ILAttributesStored.Reader f
+let mkILCustomAttrsReader f = ILAttributesStored.CreateReader(-1, f)
 
 type ILCodeLabel = int
 
@@ -1791,7 +1847,7 @@ type ILParameter =
         MetadataIndex: int32
     }
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     override x.ToString() =
         x.Name |> Option.defaultValue "<no name>"
@@ -1809,7 +1865,7 @@ type ILReturn =
 
     override x.ToString() = "<return>"
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     member x.WithCustomAttrs(customAttrs) =
         { x with
@@ -1870,7 +1926,7 @@ type ILGenericParameterDef =
         MetadataIndex: int32
     }
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     /// For debugging
     [<DebuggerBrowsable(DebuggerBrowsableState.Never)>]
@@ -1916,13 +1972,7 @@ type InterfaceImpl =
         mutable CustomAttrsStored: ILAttributesStored
     }
 
-    member x.CustomAttrs =
-        match x.CustomAttrsStored with
-        | ILAttributesStored.Reader f ->
-            let res = ILAttributes(f x.Idx)
-            x.CustomAttrsStored <- ILAttributesStored.Given res
-            res
-        | ILAttributesStored.Given attrs -> attrs
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     static member Create(ilType: ILType, customAttrsStored: ILAttributesStored) =
         {
@@ -2029,7 +2079,7 @@ type ILMethodDef
                  | Some attrs -> attrs)
         )
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs metadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     member x.SecurityDecls = x.SecurityDeclsStored.GetSecurityDecls x.MetadataIndex
 
@@ -2266,7 +2316,7 @@ type ILEventDef
 
     member _.MetadataIndex = metadataIndex
 
-    member x.CustomAttrs = customAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = customAttrsStored.CustomAttrs
 
     member x.With(?eventType, ?name, ?attributes, ?addMethod, ?removeMethod, ?fireMethod, ?otherMethods, ?customAttrs) =
         ILEventDef(
@@ -2342,7 +2392,7 @@ type ILPropertyDef
     member x.Init = init
     member x.Args = args
     member x.CustomAttrsStored = customAttrsStored
-    member x.CustomAttrs = customAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = customAttrsStored.CustomAttrs
     member x.MetadataIndex = metadataIndex
 
     member x.With(?name, ?attributes, ?setMethod, ?getMethod, ?callingConv, ?propertyType, ?init, ?args, ?customAttrs) =
@@ -2418,7 +2468,7 @@ type ILFieldDef
     member _.Offset = offset
     member _.Marshal = marshal
     member x.CustomAttrsStored = customAttrsStored
-    member x.CustomAttrs = customAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = customAttrsStored.CustomAttrs
     member x.MetadataIndex = metadataIndex
 
     member x.With
@@ -2677,8 +2727,6 @@ type ILTypeDef
         metadataIndex: int32
     ) =
 
-    let mutable customAttrsStored = customAttrsStored
-
     let hasFlag flag = additionalFlags &&& flag = flag
 
     new
@@ -2829,13 +2877,7 @@ type ILTypeDef
             customAttrs = defaultArg customAttrs x.CustomAttrsStored
         )
 
-    member x.CustomAttrs: ILAttributes =
-        match customAttrsStored with
-        | ILAttributesStored.Reader f ->
-            let res = ILAttributes(f x.MetadataIndex)
-            customAttrsStored <- ILAttributesStored.Given res
-            res
-        | ILAttributesStored.Given res -> res
+    member x.CustomAttrs: ILAttributes = customAttrsStored.CustomAttrs
 
     member x.SecurityDecls = x.SecurityDeclsStored.GetSecurityDecls x.MetadataIndex
 
@@ -2993,7 +3035,7 @@ type ILNestedExportedType =
         MetadataIndex: int32
     }
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     override x.ToString() = "exported type " + x.Name
 
@@ -3017,7 +3059,7 @@ and [<NoComparison; NoEquality>] ILExportedTypeOrForwarder =
 
     member x.IsForwarder = x.Attributes &&& enum<TypeAttributes> 0x00200000 <> enum 0
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     override x.ToString() = "exported type " + x.Name
 
@@ -3057,7 +3099,7 @@ type ILResource =
         | ILResourceLocation.Local bytes -> bytes.GetByteMemory()
         | _ -> failwith "GetBytes"
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     override x.ToString() = "resource " + x.Name
 
@@ -3104,7 +3146,7 @@ type ILAssemblyManifest =
         MetadataIndex: int32
     }
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     member x.SecurityDecls = x.SecurityDeclsStored.GetSecurityDecls x.MetadataIndex
 
@@ -3151,7 +3193,7 @@ type ILModuleDef =
         | None -> false
         | _ -> true
 
-    member x.CustomAttrs = x.CustomAttrsStored.GetCustomAttrs x.MetadataIndex
+    member x.CustomAttrs = x.CustomAttrsStored.CustomAttrs
 
     override x.ToString() = "assembly " + x.Name
 

src/Compiler/AbstractIL/il.fsi

@@ -878,15 +878,45 @@ type ILAttributes =
 
     static member internal Empty: ILAttributes
 
+[<Flags>]
+type WellKnownILAttributes =
+    | None = 0u
+    | IsReadOnlyAttribute = (1u <<< 0)
+    | IsUnmanagedAttribute = (1u <<< 1)
+    | IsByRefLikeAttribute = (1u <<< 2)
+    | ExtensionAttribute = (1u <<< 3)
+    | NullableAttribute = (1u <<< 4)
+    | ParamArrayAttribute = (1u <<< 5)
+    | AllowNullLiteralAttribute = (1u <<< 6)
+    | ReflectedDefinitionAttribute = (1u <<< 7)
+    | AutoOpenAttribute = (1u <<< 8)
+    | InternalsVisibleToAttribute = (1u <<< 9)
+    | CallerMemberNameAttribute = (1u <<< 10)
+    | CallerFilePathAttribute = (1u <<< 11)
+    | CallerLineNumberAttribute = (1u <<< 12)
+    | IDispatchConstantAttribute = (1u <<< 13)
+    | IUnknownConstantAttribute = (1u <<< 14)
+    | RequiresLocationAttribute = (1u <<< 15)
+    | SetsRequiredMembersAttribute = (1u <<< 16)
+    | NoEagerConstraintApplicationAttribute = (1u <<< 17)
+    | DefaultMemberAttribute = (1u <<< 18)
+    | ObsoleteAttribute = (1u <<< 19)
+    | CompilerFeatureRequiredAttribute = (1u <<< 20)
+    | ExperimentalAttribute = (1u <<< 21)
+    | RequiredMemberAttribute = (1u <<< 22)
+    | NullableContextAttribute = (1u <<< 23)
+    | AttributeUsageAttribute = (1u <<< 24)
+    | NotComputed = (1u <<< 31)
+
 /// Represents the efficiency-oriented storage of ILAttributes in another item.
-[<NoEquality; NoComparison>]
+[<Sealed; NoEquality; NoComparison>]
 type ILAttributesStored =
-    /// Computed by ilread.fs based on metadata index
-    | Reader of (int32 -> ILAttribute[])
-    /// Already computed
-    | Given of ILAttributes
+    member CustomAttrs: ILAttributes
+
+    member HasWellKnownAttribute: flag: WellKnownILAttributes * compute: (ILAttributes -> WellKnownILAttributes) -> bool
 
-    member GetCustomAttrs: int32 -> ILAttributes
+    static member CreateReader: idx: int32 * f: (int32 -> ILAttribute[]) -> ILAttributesStored
+    static member CreateGiven: attrs: ILAttributes -> ILAttributesStored
 
 /// Method parameters and return values.
 [<RequireQualifiedAccess; NoEquality; NoComparison>]