singrdk/base/Kernel/SingSharp.Runtime/CustomAllocator.sg

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///////////////////////////////////////////////////////////////////////////////
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
using System;
namespace Microsoft.SingSharp {
/// <summary>
/// This is the Base class for all Custom allocators.
///
/// <i>Custom Allocator support</i>
///
/// Custom allocators enable Sing# programs to allocate memory explicitly in a variety of
/// different heaps.
///
/// Pointers to objects in custom allocation regions have types that are tagged by an optional
/// type modifier pointing to the Allocator class. E.g., a pointer to a struct S in allocation
/// heap controlled by type A is given type
///
/// (S* ) opt A
///
/// In the same vein, we can support vectors in these allocation regions by tagging the pointer
/// with a vector type A[]
///
/// (S* ) opt A[] represents a vector of S in allocation region managed by A.
///
///
/// The idea is that given a pointer tagged with an allocator, we can perform operations
/// specific to that allocator, such as getting the array length, freeing the block, or
/// indirect to the data (if the allocator uses that representation).
///
/// A pointer without an allocator tag is thus interpreted no differently than the CLR normally
/// would treat it, and no special operations can be performed on it, in particular, it cannot
/// be freed.
///
/// The allocator tagging also enables us to make sure we free the pointer with the right
/// allocator and to restrict certain operations to particular heaps, for example message sends
/// only accept pointers allocated in the exchange heap.
///
/// </summary>
public class CustomAllocator {
}
/// <summary>
/// This is a marker used in optional modifiers to encode that a pointer to a custom heap is actually a
/// vector and can be indexed. We encode these as T* opt(Allocator) opt(CustomVector)
///
/// History:
/// We used to encode these as T* opt(Allocator[]), but the array type in the modifier position throws
/// off IL readers such as ABSIL.
/// </summary>
public class CustomVector {
public unsafe static void Expose(void* arr, int idx) { }
public unsafe static void UnExpose(void* arr, int idx) { }
}
}