' Licensed to the .NET Foundation under one or more agreements.
' The .NET Foundation licenses this file to you under the MIT license.
' See the LICENSE file in the project root for more information.

Imports System.Diagnostics
Imports System.Runtime.InteropServices
Imports Microsoft.CodeAnalysis.PooledObjects
Imports Microsoft.CodeAnalysis.Text
Imports Microsoft.CodeAnalysis.VisualBasic.Symbols
Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
Imports TypeKind = Microsoft.CodeAnalysis.TypeKind

Namespace Microsoft.CodeAnalysis.VisualBasic

    Partial Friend NotInheritable Class LocalRewriter

        Public Overrides Function VisitBlock(node As BoundBlock) As BoundNode

            Dim original As BoundBlock = node

            ' Static locals should be removed from the list of locals,
            ' they are replaced with fields.
            If Not node.Locals.IsEmpty Then
                Dim i As Integer
                Dim builder As ArrayBuilder(Of LocalSymbol) = Nothing

                For i = 0 To node.Locals.Length - 1
                    If node.Locals(i).IsStatic Then
                        builder = ArrayBuilder(Of LocalSymbol).GetInstance()
                        Exit For
                    End If
                Next

                If builder IsNot Nothing Then
                    builder.AddRange(node.Locals, i)

                    For i = i + 1 To node.Locals.Length - 1
                        If Not node.Locals(i).IsStatic Then
                            builder.Add(node.Locals(i))
                        End If
                    Next

                    Debug.Assert(builder.Count < node.Locals.Length)

                    node = node.Update(node.StatementListSyntax, builder.ToImmutableAndFree(), node.Statements)
                End If
            End If

            If Instrument Then
                Dim builder = ArrayBuilder(Of BoundStatement).GetInstance()

                For Each s In node.Statements
                    Dim rewrittenStatement = TryCast(Visit(s), BoundStatement)
                    If rewrittenStatement IsNot Nothing Then
                        builder.Add(rewrittenStatement)
                    End If
                Next

                Dim synthesizedLocal As LocalSymbol = Nothing
                Dim prologue As BoundStatement = _instrumenterOpt.CreateBlockPrologue(original, node, synthesizedLocal)
                If prologue IsNot Nothing Then
                    builder.Insert(0, prologue)
                End If

                Return New BoundBlock(node.Syntax, node.StatementListSyntax, If(synthesizedLocal Is Nothing, node.Locals, node.Locals.Add(synthesizedLocal)), builder.ToImmutableAndFree())
            End If

            Return MyBase.VisitBlock(node)
        End Function
    End Class
End Namespace