Optimize metadata reading for extension methods (#16168)

Co-authored-by: Petr <psfinaki@users.noreply.github.com>

docs/release-notes/.FSharp.Compiler.Service/8.0.400.md

@@ -35,3 +35,4 @@
 * Reduce allocations in compiler checking via `ValueOption` usage ([PR #16822](https://github.com/dotnet/fsharp/pull/16822))
 * Use AsyncLocal instead of ThreadStatic to hold Cancellable.Token ([PR #17156](https://github.com/dotnet/fsharp/pull/17156))
 * Showing and inserting correct name of entities from unopened namespace/module ([Issue #14375](https://github.com/dotnet/fsharp/issues/14375), [PR #17261](https://github.com/dotnet/fsharp/pull/17261))
+* Support lazy custom attributes calculation for `ILTypeDef` public API, improve `ExtensionAttribute` presence detecting perf. ([PR #16168](https://github.com/dotnet/fsharp/pull/16168))

src/Compiler/AbstractIL/il.fs

@@ -1258,6 +1258,9 @@ let storeILCustomAttrs (attrs: ILAttributes) =
  else
  ILAttributesStored.Given attrs
 
+let mkILCustomAttrsComputed f =
+ ILAttributesStored.Reader(fun _ -> f ())
+
 let mkILCustomAttrsReader f = ILAttributesStored.Reader f
 
 type ILCodeLabel = int
@@ -2611,6 +2614,14 @@ let convertInitSemantics (init: ILTypeInit) =
  | ILTypeInit.BeforeField -> TypeAttributes.BeforeFieldInit
  | ILTypeInit.OnAny -> enum 0
 
+[<Flags>]
+type ILTypeDefAdditionalFlags =
+ | None = 0
+ | IsKnownToBeAttribute = 1
+ /// The type can contain extension methods,
+ /// or this information may not be available at the time the ILTypeDef is created
+ | CanContainExtensionMethods = 2
+
 [<NoComparison; NoEquality; StructuredFormatDisplay("{DebugText}")>]
 type ILTypeDef
  (
@@ -2626,14 +2637,16 @@ type ILTypeDef
  methodImpls: ILMethodImplDefs,
  events: ILEventDefs,
  properties: ILPropertyDefs,
- isKnownToBeAttribute: bool,
+ additionalFlags: ILTypeDefAdditionalFlags,
  securityDeclsStored: ILSecurityDeclsStored,
  customAttrsStored: ILAttributesStored,
  metadataIndex: int32
  ) =
 
  let mutable customAttrsStored = customAttrsStored
 
+ let hasFlag flag = additionalFlags &&& flag = flag
+
  new(name,
  attributes,
  layout,
@@ -2646,7 +2659,7 @@ type ILTypeDef
  methodImpls,
  events,
  properties,
- isKnownToBeAttribute,
+ additionalFlags,
  securityDecls,
  customAttrs) =
  ILTypeDef(
@@ -2662,9 +2675,9 @@ type ILTypeDef
  methodImpls,
  events,
  properties,
- isKnownToBeAttribute,
+ additionalFlags,
  storeILSecurityDecls securityDecls,
- storeILCustomAttrs customAttrs,
+ customAttrs,
  NoMetadataIdx
  )
 
@@ -2694,7 +2707,10 @@ type ILTypeDef
 
  member _.Properties = properties
 
- member _.IsKnownToBeAttribute = isKnownToBeAttribute
+ member _.IsKnownToBeAttribute = hasFlag ILTypeDefAdditionalFlags.IsKnownToBeAttribute
+
+ member _.CanContainExtensionMethods =
+ hasFlag ILTypeDefAdditionalFlags.CanContainExtensionMethods
 
  member _.CustomAttrsStored = customAttrsStored
 
@@ -2714,7 +2730,7 @@ type ILTypeDef
  ?methodImpls,
  ?events,
  ?properties,
- ?isKnownToBeAttribute,
+ ?newAdditionalFlags,
  ?customAttrs,
  ?securityDecls
  ) =
@@ -2732,11 +2748,11 @@ type ILTypeDef
  methodImpls = defaultArg methodImpls x.MethodImpls,
  events = defaultArg events x.Events,
  properties = defaultArg properties x.Properties,
- isKnownToBeAttribute = defaultArg isKnownToBeAttribute x.IsKnownToBeAttribute,
- customAttrs = defaultArg customAttrs x.CustomAttrs
+ additionalFlags = defaultArg newAdditionalFlags additionalFlags,
+ customAttrs = defaultArg customAttrs (storeILCustomAttrs x.CustomAttrs)
  )
 
- member x.CustomAttrs =
+ member x.CustomAttrs: ILAttributes =
  match customAttrsStored with
  | ILAttributesStored.Reader f ->
  let res = ILAttributes(f x.MetadataIndex)
@@ -4220,11 +4236,11 @@ let mkILGenericClass (nm, access, genparams, extends, impl, methods, fields, nes
  methods = methods,
  fields = fields,
  nestedTypes = nestedTypes,
- customAttrs = attrs,
+ customAttrs = storeILCustomAttrs attrs,
  methodImpls = emptyILMethodImpls,
  properties = props,
  events = events,
- isKnownToBeAttribute = false,
+ additionalFlags = ILTypeDefAdditionalFlags.None,
  securityDecls = emptyILSecurityDecls
  )
 
@@ -4244,11 +4260,11 @@ let mkRawDataValueTypeDef (iltyp_ValueType: ILType) (nm, size, pack) =
  methods = emptyILMethods,
  fields = emptyILFields,
  nestedTypes = emptyILTypeDefs,
- customAttrs = emptyILCustomAttrs,
+ customAttrs = emptyILCustomAttrsStored,
  methodImpls = emptyILMethodImpls,
  properties = emptyILProperties,
  events = emptyILEvents,
- isKnownToBeAttribute = false,
+ additionalFlags = ILTypeDefAdditionalFlags.None,
  securityDecls = emptyILSecurityDecls
  )
 

src/Compiler/AbstractIL/il.fsi

@@ -4,6 +4,7 @@
 
 module rec FSharp.Compiler.AbstractIL.IL
 
+open System
 open FSharp.Compiler.IO
 open System.Collections.Generic
 open System.Reflection
@@ -1481,6 +1482,12 @@ type ILTypeDefs =
  /// Calls to <c>ExistsByName</c> will result in all the ILPreTypeDefs being read.
  member internal ExistsByName: string -> bool
 
+[<Flags>]
+type ILTypeDefAdditionalFlags =
+ | None = 0
+ | IsKnownToBeAttribute = 1
+ | CanContainExtensionMethods = 2
+
 /// Represents IL Type Definitions.
 [<NoComparison; NoEquality>]
 type ILTypeDef =
@@ -1499,7 +1506,7 @@ type ILTypeDef =
  methodImpls: ILMethodImplDefs *
  events: ILEventDefs *
  properties: ILPropertyDefs *
- isKnownToBeAttribute: bool *
+ additionalFlags: ILTypeDefAdditionalFlags *
  securityDeclsStored: ILSecurityDeclsStored *
  customAttrsStored: ILAttributesStored *
  metadataIndex: int32 ->
@@ -1519,9 +1526,9 @@ type ILTypeDef =
  methodImpls: ILMethodImplDefs *
  events: ILEventDefs *
  properties: ILPropertyDefs *
- isKnownToBeAttribute: bool *
+ additionalFlags: ILTypeDefAdditionalFlags *
  securityDecls: ILSecurityDecls *
- customAttrs: ILAttributes ->
+ customAttrs: ILAttributesStored ->
  ILTypeDef
 
  member Name: string
@@ -1556,6 +1563,7 @@ type ILTypeDef =
  member HasSecurity: bool
  member Encoding: ILDefaultPInvokeEncoding
  member IsKnownToBeAttribute: bool
+ member CanContainExtensionMethods: bool
 
  member internal WithAccess: ILTypeDefAccess -> ILTypeDef
  member internal WithNestedAccess: ILMemberAccess -> ILTypeDef
@@ -1584,8 +1592,8 @@ type ILTypeDef =
  ?methodImpls: ILMethodImplDefs *
  ?events: ILEventDefs *
  ?properties: ILPropertyDefs *
- ?isKnownToBeAttribute: bool *
- ?customAttrs: ILAttributes *
+ ?newAdditionalFlags: ILTypeDefAdditionalFlags *
+ ?customAttrs: ILAttributesStored *
  ?securityDecls: ILSecurityDecls ->
  ILTypeDef
 
@@ -2212,8 +2220,10 @@ val internal mkILTypeForGlobalFunctions: ILScopeRef -> ILType
 val mkILCustomAttrs: ILAttribute list -> ILAttributes
 val mkILCustomAttrsFromArray: ILAttribute[] -> ILAttributes
 val storeILCustomAttrs: ILAttributes -> ILAttributesStored
+val mkILCustomAttrsComputed: (unit -> ILAttribute[]) -> ILAttributesStored
 val internal mkILCustomAttrsReader: (int32 -> ILAttribute[]) -> ILAttributesStored
 val emptyILCustomAttrs: ILAttributes
+val emptyILCustomAttrsStored: ILAttributesStored
 
 val mkILSecurityDecls: ILSecurityDecl list -> ILSecurityDecls
 val emptyILSecurityDecls: ILSecurityDecls

src/Compiler/AbstractIL/ilmorph.fs

@@ -378,7 +378,7 @@ let rec tdef_ty2ty_ilmbody2ilmbody_mdefs2mdefs isInKnownSet enc fs (tdef: ILType
  methodImpls = mimpls_ty2ty fTyInCtxtR tdef.MethodImpls,
  events = edefs_ty2ty fTyInCtxtR tdef.Events,
  properties = pdefs_ty2ty fTyInCtxtR tdef.Properties,
- customAttrs = cattrs_ty2ty fTyInCtxtR tdef.CustomAttrs
+ customAttrs = storeILCustomAttrs (cattrs_ty2ty fTyInCtxtR tdef.CustomAttrs)
  )
 
 and tdefs_ty2ty_ilmbody2ilmbody_mdefs2mdefs isInKnownSet enc fs tdefs =

src/Compiler/AbstractIL/ilread.fs

@@ -858,10 +858,10 @@ let hsCompare (TaggedIndex(t1: HasSemanticsTag, idx1: int)) (TaggedIndex(t2: Has
  elif idx1 > idx2 then 1
  else compare t1.Tag t2.Tag
 
-let hcaCompare (TaggedIndex(t1: HasCustomAttributeTag, idx1: int)) (TaggedIndex(t2: HasCustomAttributeTag, idx2)) =
- if idx1 < idx2 then -1
- elif idx1 > idx2 then 1
- else compare t1.Tag t2.Tag
+let inline hcaCompare (t1: TaggedIndex<HasCustomAttributeTag>) (t2: TaggedIndex<HasCustomAttributeTag>) =
+ if t1.index < t2.index then -1
+ elif t1.index > t2.index then 1
+ else compare t1.tag t2.tag
 
 let mfCompare (TaggedIndex(t1: MemberForwardedTag, idx1: int)) (TaggedIndex(t2: MemberForwardedTag, idx2)) =
  if idx1 < idx2 then -1
@@ -2112,9 +2112,82 @@ and typeDefReader ctxtH : ILTypeDefStored =
  let layout = typeLayoutOfFlags ctxt mdv flags idx
 
  let hasLayout =
- (match layout with
- | ILTypeDefLayout.Explicit _ -> true
- | _ -> false)
+ match layout with
+ | ILTypeDefLayout.Explicit _ -> true
+ | _ -> false
+
+ let containsExtensionMethods =
+ let mutable containsExtensionMethods = false
+ let searchedKey = TaggedIndex(hca_TypeDef, idx)
+
+ let attributesSearcher =
+ { new ISeekReadIndexedRowReader<int, int, int> with
+ member _.GetRow(i, rowIndex) = rowIndex <- i
+ member _.GetKey(rowIndex) = rowIndex
+
+ member _.CompareKey(rowIndex) =
+ let mutable addr = ctxt.rowAddr TableNames.CustomAttribute rowIndex
+ // read parentIndex
+ let key = seekReadHasCustomAttributeIdx ctxt mdv &addr
+ hcaCompare searchedKey key
+
+ member _.ConvertRow(i) = i
+ }
+
+ let attrsStartIdx, attrsEndIdx =
+ seekReadIndexedRowsRange
+ (ctxt.getNumRows TableNames.CustomAttribute)
+ (isSorted ctxt TableNames.CustomAttribute)
+ attributesSearcher
+
+ if attrsStartIdx <= 0 || attrsEndIdx < attrsStartIdx then
+ false
+ else
+ let mutable attrIdx = attrsStartIdx
+
+ let looksLikeSystemAssembly =
+ ctxt.fileName.EndsWith("System.Runtime.dll")
+ || ctxt.fileName.EndsWith("mscorlib.dll")
+ || ctxt.fileName.EndsWith("netstandard.dll")
+
+ while attrIdx <= attrsEndIdx && not containsExtensionMethods do
+ let mutable addr = ctxt.rowAddr TableNames.CustomAttribute attrIdx
+ // skip parentIndex to read typeIndex
+ seekReadHasCustomAttributeIdx ctxt mdv &addr |> ignore
+ let attrTypeIndex = seekReadCustomAttributeTypeIdx ctxt mdv &addr
+ let attrCtorIdx = attrTypeIndex.index
+
+ let name =
+ if attrTypeIndex.tag = cat_MethodDef then
+ // the ExtensionAttribute constructor can be cat_MethodDef if the metadata is read from the assembly
+ // in which the corresponding attribute is defined -- from the system library
+ if not looksLikeSystemAssembly then
+ ""
+ else
+ let _, (_, nameIdx, namespaceIdx, _, _, _) = seekMethodDefParent ctxt attrCtorIdx
+ readBlobHeapAsTypeName ctxt (nameIdx, namespaceIdx)
+ else
+ let mutable addr = ctxt.rowAddr TableNames.MemberRef attrCtorIdx
+ let mrpTag = seekReadMemberRefParentIdx ctxt mdv &addr
+
+ if mrpTag.tag <> mrp_TypeRef then
+ ""
+ else
+ let _, nameIdx, namespaceIdx = seekReadTypeRefRow ctxt mdv mrpTag.index
+ readBlobHeapAsTypeName ctxt (nameIdx, namespaceIdx)
+
+ if name = "System.Runtime.CompilerServices.ExtensionAttribute" then
+ containsExtensionMethods <- true
+
+ attrIdx <- attrIdx + 1
+
+ containsExtensionMethods
+
+ let additionalFlags =
+ if containsExtensionMethods then
+ ILTypeDefAdditionalFlags.CanContainExtensionMethods
+ else
+ ILTypeDefAdditionalFlags.None
 
  let mdefs = seekReadMethods ctxt numTypars methodsIdx endMethodsIdx
  let fdefs = seekReadFields ctxt (numTypars, hasLayout) fieldsIdx endFieldsIdx
@@ -2138,7 +2211,7 @@ and typeDefReader ctxtH : ILTypeDefStored =
  methodImpls = mimpls,
  events = events,
  properties = props,
- isKnownToBeAttribute = false,
+ additionalFlags = additionalFlags,
  customAttrsStored = ctxt.customAttrsReader_TypeDef,
  metadataIndex = idx
  ))
@@ -2797,22 +2870,26 @@ and seekReadMemberRefAsFieldSpecUncached ctxtH (MemberRefAsFspecIdx(numTypars, i
 // method-range and field-range start/finish indexes
 and seekReadMethodDefAsMethodData ctxt idx = ctxt.seekReadMethodDefAsMethodData idx
 
+and seekMethodDefParent (ctxt: ILMetadataReader) methodIdx =
+ seekReadIndexedRow (
+ ctxt.getNumRows TableNames.TypeDef,
+ (fun i -> i, seekReadTypeDefRow ctxt i),
+ id,
+ (fun (i, (_, _, _, _, _, methodsIdx as info)) ->
+ if methodsIdx > methodIdx then
+ -1
+ else
+ let struct (_, endMethodsIdx) = seekReadTypeDefRowExtents ctxt info i
+ if endMethodsIdx <= methodIdx then 1 else 0),
+ true,
+ id
+ )
+
 and seekReadMethodDefAsMethodDataUncached ctxtH idx =
  let (ctxt: ILMetadataReader) = getHole ctxtH
  let mdv = ctxt.mdfile.GetView()
  // Look for the method def parent.
- let tidx =
- seekReadIndexedRow (
- ctxt.getNumRows TableNames.TypeDef,
- (fun i -> i, seekReadTypeDefRowWithExtents ctxt i),
- id,
- (fun (_, ((_, _, _, _, _, methodsIdx), (_, endMethodsIdx))) ->
- if endMethodsIdx <= idx then 1
- elif methodsIdx <= idx && idx < endMethodsIdx then 0
- else -1),
- true,
- fst
- )
+ let tidx, _ = seekMethodDefParent ctxt idx
  // Create a formal instantiation if needed
  let typeGenericArgs = seekReadGenericParams ctxt 0 (tomd_TypeDef, tidx)
  let typeGenericArgsCount = typeGenericArgs.Length

src/Compiler/Checking/NameResolution.fs

@@ -524,7 +524,10 @@ let NextExtensionMethodPriority() = uint64 (newStamp())
 /// Checks if the type is used for C# style extension members.
 let IsTyconRefUsedForCSharpStyleExtensionMembers g m (tcref: TyconRef) =
  // Type must be non-generic and have 'Extension' attribute
- isNil(tcref.Typars m) && TyconRefHasAttribute g m g.attrib_ExtensionAttribute tcref
+ match metadataOfTycon tcref.Deref with
+ | ILTypeMetadata(TILObjectReprData(_, _, tdef)) -> tdef.CanContainExtensionMethods
+ | _ -> true
+ && isNil(tcref.Typars m) && TyconRefHasAttribute g m g.attrib_ExtensionAttribute tcref
 
 /// Checks if the type is used for C# style extension members.
 let IsTypeUsedForCSharpStyleExtensionMembers g m ty =