Skip to content

Use optimized hash creation methods on .NET 5+ #67999

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Apr 28, 2023
Merged

Use optimized hash creation methods on .NET 5+ #67999

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
618b3b0
Use optimized hash creation methods on .NET 5+
sharwell Apr 27, 2023
48e9cc5
Avoid finalizable internal state for non-FIPS scenarios
sharwell Apr 27, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
115 changes: 81 additions & 34 deletions src/Workspaces/Core/Portable/Workspace/Solution/Checksum_Factory.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,15 +5,14 @@
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.IO;
using System.Security.Cryptography;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Threading;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Serialization;
using Roslyn.Utilities;
using System.Diagnostics;
using System.Runtime.CompilerServices;

namespace Microsoft.CodeAnalysis
{
Expand All @@ -23,47 +22,102 @@ internal partial class Checksum
// https://github.com/dotnet/runtime/blob/f2db6d6093c54e5eeb9db2d8dcbe15b2db92ad8c/src/libraries/System.Security.Cryptography.Algorithms/src/System/Security/Cryptography/SHA256.cs#L18-L19
private const int SHA256HashSizeBytes = 256 / 8;

#if NET5_0_OR_GREATER
private static readonly ObjectPool<IncrementalHash> s_incrementalHashPool =
new(() => IncrementalHash.CreateHash(HashAlgorithmName.SHA256), size: 20);
#else
private static readonly ObjectPool<SHA256> s_incrementalHashPool =
new(SHA256.Create, size: 20);
#endif

#if !NET5_0_OR_GREATER
// Dedicated pools for the byte[]s we use to create checksums from two or three existing checksums. Sized to
// exactly the space needed to splat the existing checksum data into the array and then hash it.

private static readonly ObjectPool<byte[]> s_twoChecksumByteArrayPool = new(() => new byte[HashSize * 2]);
private static readonly ObjectPool<byte[]> s_threeChecksumByteArrayPool = new(() => new byte[HashSize * 3]);
#endif

public static Checksum Create(IEnumerable<string> values)
{
#if NET5_0_OR_GREATER
using var pooledHash = s_incrementalHashPool.GetPooledObject();

foreach (var value in values)
{
pooledHash.Object.AppendData(MemoryMarshal.AsBytes(value.AsSpan()));
pooledHash.Object.AppendData(MemoryMarshal.AsBytes("\0".AsSpan()));
}

Span<byte> hash = stackalloc byte[SHA256HashSizeBytes];
pooledHash.Object.GetHashAndReset(hash);
return From(hash);
#else
using var pooledHash = s_incrementalHashPool.GetPooledObject();
using var pooledBuffer = SharedPools.ByteArray.GetPooledObject();
var hash = pooledHash.Object;

hash.Initialize();
foreach (var value in values)
{
AppendData(hash, pooledBuffer.Object, value);
AppendData(hash, pooledBuffer.Object, "\0");
}

return From(hash.GetHashAndReset());
hash.TransformFinalBlock(Array.Empty<byte>(), 0, 0);
return From(hash.Hash);
#endif
}

public static Checksum Create(string value)
{
#if NET5_0_OR_GREATER
Span<byte> hash = stackalloc byte[SHA256HashSizeBytes];
SHA256.HashData(MemoryMarshal.AsBytes(value.AsSpan()), hash);
return From(hash);
#else
using var pooledHash = s_incrementalHashPool.GetPooledObject();
using var pooledBuffer = SharedPools.ByteArray.GetPooledObject();
var hash = pooledHash.Object;
hash.Initialize();

AppendData(hash, pooledBuffer.Object, value);

return From(hash.GetHashAndReset());
hash.TransformFinalBlock(Array.Empty<byte>(), 0, 0);
return From(hash.Hash);
#endif
}

public static Checksum Create(Stream stream)
{
#if NET7_0_OR_GREATER
Span<byte> hash = stackalloc byte[SHA256HashSizeBytes];
SHA256.HashData(stream, hash);
return From(hash);
#elif NET5_0_OR_GREATER
using var pooledHash = s_incrementalHashPool.GetPooledObject();
Span<byte> buffer = stackalloc byte[SharedPools.ByteBufferSize];
Copy link
Member

@stephentoub stephentoub Apr 27, 2023

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

4K is a much larger buffer than we typically like to stackalloc. It might be fine for your scenarios, just calling it out. We have a rough guideline of not stackalloc'ing more than 1K.

Copy link
Member

@stephentoub stephentoub Apr 27, 2023

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

(Also, keep in mind this whole buffer will be zero'd unless you're using SkipLocalsInit.)


int bytesRead;
do
{
bytesRead = stream.Read(buffer);
if (bytesRead > 0)
{
pooledHash.Object.AppendData(buffer[..bytesRead]);
}
}
while (bytesRead > 0);

Span<byte> hash = stackalloc byte[SHA256HashSizeBytes];
pooledHash.Object.GetHashAndReset(hash);
return From(hash);
#else
using var pooledHash = s_incrementalHashPool.GetPooledObject();
using var pooledBuffer = SharedPools.ByteArray.GetPooledObject();

var hash = pooledHash.Object;
hash.Initialize();

var buffer = pooledBuffer.Object;
var bufferLength = buffer.Length;
Expand All @@ -73,12 +127,13 @@ public static Checksum Create(Stream stream)
bytesRead = stream.Read(buffer, 0, bufferLength);
if (bytesRead > 0)
{
hash.AppendData(buffer, 0, bytesRead);
hash.TransformBlock(buffer, 0, bytesRead, null, 0);
}
}
while (bytesRead > 0);

var bytes = hash.GetHashAndReset();
hash.TransformFinalBlock(Array.Empty<byte>(), 0, 0);
var bytes = hash.Hash;

// if bytes array is bigger than certain size, checksum
// will truncate it to predetermined size. for more detail,
Expand All @@ -91,6 +146,7 @@ public static Checksum Create(Stream stream)
// hash algorithm used here should remain functionally correct even
// after the truncation
return From(bytes);
#endif
}

public static Checksum Create(IObjectWritable @object)
Expand Down Expand Up @@ -124,36 +180,44 @@ public static Checksum Create(Checksum checksum1, Checksum checksum2, Checksum c
#endif
}

#if !NET5_0_OR_GREATER

private static Checksum CreateUsingByteArrays(Checksum checksum1, Checksum checksum2)
{
using var hash = s_incrementalHashPool.GetPooledObject();
using var bytes = s_twoChecksumByteArrayPool.GetPooledObject();

var bytesSpan = bytes.Object.AsSpan();
checksum1.WriteTo(bytesSpan);
checksum2.WriteTo(bytesSpan.Slice(HashSize));

hash.Object.AppendData(bytes.Object);
using var hash = s_incrementalHashPool.GetPooledObject();
hash.Object.Initialize();

hash.Object.TransformBlock(bytes.Object, 0, bytes.Object.Length, null, 0);

return From(hash.Object.GetHashAndReset());
hash.Object.TransformFinalBlock(Array.Empty<byte>(), 0, 0);
return From(hash.Object.Hash);
}

private static Checksum CreateUsingByteArrays(Checksum checksum1, Checksum checksum2, Checksum checksum3)
{
using var hash = s_incrementalHashPool.GetPooledObject();
using var bytes = s_threeChecksumByteArrayPool.GetPooledObject();

var bytesSpan = bytes.Object.AsSpan();
checksum1.WriteTo(bytesSpan);
checksum2.WriteTo(bytesSpan.Slice(HashSize));
checksum3.WriteTo(bytesSpan.Slice(2 * HashSize));

hash.Object.AppendData(bytes.Object);
using var hash = s_incrementalHashPool.GetPooledObject();
hash.Object.Initialize();

hash.Object.TransformBlock(bytes.Object, 0, bytes.Object.Length, null, 0);

return From(hash.Object.GetHashAndReset());
hash.Object.TransformFinalBlock(Array.Empty<byte>(), 0, 0);
return From(hash.Object.Hash);
}

#if NET
#else

// Optimized helpers that do not need to allocate any arrays to combine hashes.

Expand Down Expand Up @@ -234,7 +298,8 @@ public static Checksum Create(ParseOptions value, ISerializerService serializer)
return Create(stream);
}

private static void AppendData(IncrementalHash hash, byte[] buffer, string value)
#if !NET5_0_OR_GREATER
private static void AppendData(SHA256 hash, byte[] buffer, string value)
{
var stringBytes = MemoryMarshal.AsBytes(value.AsSpan());
Debug.Assert(stringBytes.Length == value.Length * 2);
Expand All @@ -246,29 +311,11 @@ private static void AppendData(IncrementalHash hash, byte[] buffer, string value
var toCopy = Math.Min(remaining, buffer.Length);

stringBytes.Slice(index, toCopy).CopyTo(buffer);
hash.AppendData(buffer, 0, toCopy);
hash.TransformBlock(buffer, 0, toCopy, null, 0);

index += toCopy;
}
}

public static class TestAccessor
{
public static Checksum CreateUsingByteArrays(Checksum checksum1, Checksum checksum2)
=> Checksum.CreateUsingByteArrays(checksum1, checksum2);

public static Checksum CreateUsingByteArrays(Checksum checksum1, Checksum checksum2, Checksum checksum3)
=> Checksum.CreateUsingByteArrays(checksum1, checksum2, checksum3);

#if NET

public static Checksum CreateUsingSpans(Checksum checksum1, Checksum checksum2)
=> Checksum.CreateUsingSpans(checksum1, checksum2);

public static Checksum CreateUsingSpans(Checksum checksum1, Checksum checksum2, Checksum checksum3)
=> Checksum.CreateUsingSpans(checksum1, checksum2, checksum3);

#endif
}
}
}
25 changes: 6 additions & 19 deletions src/Workspaces/CoreTest/ChecksumTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,35 +2,26 @@
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xunit;

namespace Microsoft.CodeAnalysis.UnitTests
{
public class ChecksumTests
{
#if NET
[Fact]
public void ValidateChecksumFromSpanSameAsChecksumFromBytes1()
{
var checksum1 = Checksum.Create("Goo");
var checksum2 = Checksum.Create("Bar");

var checksumA = Checksum.TestAccessor.CreateUsingByteArrays(checksum1, checksum2);
var checksumB = Checksum.TestAccessor.CreateUsingSpans(checksum1, checksum2);
var checksumA = Checksum.Create(checksum1, checksum2);

Assert.Equal(checksumA, checksumB);
// Running this test on multiple target frameworks with the same expectation ensures the results match
Assert.Equal(Checksum.FromBase64String("N30m5jwVeMZzWpy9cbQbtSYHoXU="), checksumA);

Assert.NotEqual(checksum1, checksum2);

Assert.NotEqual(checksum1, checksumA);
Assert.NotEqual(checksum1, checksumB);
Assert.NotEqual(checksum2, checksumA);
Assert.NotEqual(checksum2, checksumB);
}

[Fact]
Expand All @@ -40,22 +31,18 @@ public void ValidateChecksumFromSpanSameAsChecksumFromBytes2()
var checksum2 = Checksum.Create("Bar");
var checksum3 = Checksum.Create("Baz");

var checksumA = Checksum.TestAccessor.CreateUsingByteArrays(checksum1, checksum2, checksum3);
var checksumB = Checksum.TestAccessor.CreateUsingSpans(checksum1, checksum2, checksum3);
var checksumA = Checksum.Create(checksum1, checksum2, checksum3);

Assert.Equal(checksumA, checksumB);
// Running this test on multiple target frameworks with the same expectation ensures the results match
Assert.Equal(Checksum.FromBase64String("NEfIznmqkIqi4VJl12KxycWt7uo="), checksumA);

Assert.NotEqual(checksum1, checksum2);
Assert.NotEqual(checksum2, checksum3);
Assert.NotEqual(checksum3, checksum1);

Assert.NotEqual(checksum1, checksumA);
Assert.NotEqual(checksum1, checksumB);
Assert.NotEqual(checksum2, checksumA);
Assert.NotEqual(checksum2, checksumB);
Assert.NotEqual(checksum3, checksumA);
Assert.NotEqual(checksum3, checksumB);
}
#endif
}
}