Revert TcSymbolUseData cleanup per dotnet#6084 (dotnet#6089)

src/absil/illib.fs

@@ -39,10 +39,6 @@ let inline nonNull msg x = if isNull x then failwith ("null: " + msg) else x
 
 let inline (===) x y = LanguagePrimitives.PhysicalEquality x y
 
-/// Per the docs the threshold for the Large Object Heap is 85000 bytes: https://docs.microsoft.com/en-us/dotnet/standard/garbage-collection/large-object-heap#how-an-object-ends-up-on-the-large-object-heap-and-how-gc-handles-them
-/// We set the limit to be 80k to account for larger pointer sizes for when F# is running 64-bit.
-let LOH_SIZE_THRESHOLD_BYTES = 80_000
-
 //---------------------------------------------------------------------
 // Library: ReportTime
 //---------------------------------------------------------------------
@@ -415,48 +411,9 @@ module List =
 
     let mapiFoldSquared f z xss = mapFoldSquared f z (xss |> mapiSquared (fun i j x -> (i, j, x)))
 
-module ResizeArray =
-
-    /// Split a ResizeArray into an array of smaller chunks.
-    /// This requires `items/chunkSize` Array copies of length `chunkSize` if `items/chunkSize % 0 = 0`,
-    /// otherwise `items/chunkSize + 1` Array copies.
-    let chunkBySize chunkSize f (items: ResizeArray<'t>) =
-        // we could use Seq.chunkBySize here, but that would involve many enumerator.MoveNext() calls that we can sidestep with a bit of math
-        let itemCount = items.Count
-        if itemCount = 0
-        then [||]
-        else
-            let chunksCount =
-                match itemCount / chunkSize with
-                | n when itemCount % chunkSize = 0 -> n
-                | n -> n + 1 // any remainder means we need an additional chunk to store it
-
-            [| for index in 0..chunksCount-1 do
-                let startIndex = index * chunkSize
-                let takeCount = min (itemCount - startIndex) chunkSize
-
-                let holder = Array.zeroCreate takeCount
-                // we take a bounds-check hit here on each access.
-                // other alternatives here include
-                // * iterating across an IEnumerator (incurs MoveNext penalty)
-                // * doing a block copy using `List.CopyTo(index, array, index, count)` (requires more copies to do the mapping)
-                // none are significantly better.
-                for i in 0 .. takeCount - 1 do
-                    holder.[i] <- f items.[i]
-                yield holder |]
-
-    /// Split a large ResizeArray into a series of array chunks that are each under the Large Object Heap limit.
-    /// This is done to help prevent a stop-the-world collection of the single large array, instead allowing for a greater
-    /// probability of smaller collections. Stop-the-world is still possible, just less likely.
-    let mapToSmallArrayChunks f (inp: ResizeArray<'t>) =
-        let itemSizeBytes = sizeof<'t>
-        // rounding down here is good because it ensures we don't go over
-        let maxArrayItemCount = LOH_SIZE_THRESHOLD_BYTES / itemSizeBytes
-
-        /// chunk the provided input into arrays that are smaller than the LOH limit
-        /// in order to prevent long-term storage of those values
-        chunkBySize maxArrayItemCount f inp
-
+/// Because FSharp.Compiler.Service is a library that will target FSharp.Core 4.5.2 for the forseeable future,
+/// we need to stick these functions in this module rather than using the module functions for ValueOption
+/// that come after FSharp.Core 4.5.2.
 module ValueOptionInternal =
 
     let inline ofOption x = match x with Some x -> ValueSome x | None -> ValueNone

src/fsharp/NameResolution.fs

@@ -1403,7 +1403,7 @@ let GetNestedTypesOfType (ad, ncenv: NameResolver, optFilter, staticResInfo, che
 //-------------------------------------------------------------------------
 
 /// Represents the kind of the occurrence when reporting a name in name resolution
-[<RequireQualifiedAccess; Struct>]
+[<RequireQualifiedAccess>]
 type ItemOccurence =
     /// This is a binding / declaration of the item
     | Binding
@@ -1701,24 +1701,17 @@ type TcSymbolUseData =
 /// This is a memory-critical data structure - allocations of this data structure and its immediate contents
 /// is one of the highest memory long-lived data structures in typical uses of IDEs. Not many of these objects
 /// are allocated (one per file), but they are large because the allUsesOfAllSymbols array is large.
-type TcSymbolUses(g, capturedNameResolutions: ResizeArray<CapturedNameResolution>, formatSpecifierLocations: (range * int)[]) =
-
+type TcSymbolUses(g, capturedNameResolutions: ResizeArray<CapturedNameResolution>, formatSpecifierLocations: (range * int)[]) = 
+    
     // Make sure we only capture the information we really need to report symbol uses
-    let allUsesOfSymbols =
-        capturedNameResolutions
-        |> ResizeArray.mapToSmallArrayChunks (fun cnr -> { Item=cnr.Item; ItemOccurence=cnr.ItemOccurence; DisplayEnv=cnr.DisplayEnv; Range=cnr.Range })
-
+    let allUsesOfSymbols = [| for cnr in capturedNameResolutions -> { Item=cnr.Item; ItemOccurence=cnr.ItemOccurence; DisplayEnv=cnr.DisplayEnv; Range=cnr.Range } |]
     let capturedNameResolutions = ()
     do ignore capturedNameResolutions // don't capture this!
 
     member this.GetUsesOfSymbol item =
-        // This member returns what is potentially a very large array, which may approach the size constraints of the Large Object Heap.
-        // This is unlikely in practice, though, because we filter down the set of all symbol uses to those specifically for the given `item`.
-        // Consequently we have a much lesser chance of ending up with an array large enough to be promoted to the LOH.
-        [| for symbolUseChunk in allUsesOfSymbols do
-            for symbolUse in symbolUseChunk do
-                if protectAssemblyExploration false (fun () -> ItemsAreEffectivelyEqual g item symbolUse.Item) then
-                    yield symbolUse |]
+        [| for symbolUse in allUsesOfSymbols do
+               if protectAssemblyExploration false (fun () -> ItemsAreEffectivelyEqual g item symbolUse.Item) then
+                  yield symbolUse |]
 
     member this.AllUsesOfSymbols = allUsesOfSymbols
 

src/fsharp/NameResolution.fsi

@@ -282,7 +282,7 @@ type TypeNameResolutionInfo =
   static member ResolveToTypeRefs : TypeNameResolutionStaticArgsInfo -> TypeNameResolutionInfo
 
 /// Represents the kind of the occurrence when reporting a name in name resolution
-[<RequireQualifiedAccess; Struct>]
+[<RequireQualifiedAccess>]
 type internal ItemOccurence = 
     | Binding 
     | Use 
@@ -363,7 +363,7 @@ type internal TcSymbolUses =
     member GetUsesOfSymbol : Item -> TcSymbolUseData[]
 
     /// All the uses of all items within the file
-    member AllUsesOfSymbols : TcSymbolUseData[][]
+    member AllUsesOfSymbols : TcSymbolUseData[]
 
     /// Get the locations of all the printf format specifiers in the file
     member GetFormatSpecifierLocationsAndArity : unit -> (range * int)[]

src/fsharp/service/FSharpCheckerResults.fs

@@ -1861,8 +1861,7 @@ type FSharpCheckFileResults
             (fun () -> [| |])
             (fun scope ->
                 let cenv = scope.SymbolEnv
-                [| for symbolUseChunk in scope.ScopeSymbolUses.AllUsesOfSymbols do
-                    for symbolUse in symbolUseChunk do
+                [| for symbolUse in scope.ScopeSymbolUses.AllUsesOfSymbols do
                     if symbolUse.ItemOccurence <> ItemOccurence.RelatedText then
                         let symbol = FSharpSymbol.Create(cenv, symbolUse.Item)
                         yield FSharpSymbolUse(scope.TcGlobals, symbolUse.DisplayEnv, symbol, symbolUse.ItemOccurence, symbolUse.Range) |])
@@ -2087,8 +2086,7 @@ type FSharpCheckProjectResults
         let cenv = SymbolEnv(tcGlobals, thisCcu, Some ccuSig, tcImports)
 
         [| for r in tcSymbolUses do
-            for symbolUseChunk in r.AllUsesOfSymbols do
-                for symbolUse in symbolUseChunk do
+            for symbolUse in r.AllUsesOfSymbols do
                     if symbolUse.ItemOccurence <> ItemOccurence.RelatedText then
                       let symbol = FSharpSymbol.Create(cenv, symbolUse.Item)
                       yield FSharpSymbolUse(tcGlobals, symbolUse.DisplayEnv, symbol, symbolUse.ItemOccurence, symbolUse.Range) |]