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Fix alignment padding and add test for saving managed resources #110915

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merged 7 commits into from
Feb 15, 2025
+168 −70
Merged

Fix alignment padding and add test for saving managed resources #110915

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f21da2f
Add test for saving and reading managed resources
steveharter Dec 23, 2024
d199ed7
Use TempFile helper for tests; align Resource section
steveharter Dec 23, 2024
c011569
Align just the resource buffer
steveharter Dec 23, 2024
f857e01
Verify ManagedPEBuilder.Serialize() doesn't modify incoming resource …
steveharter Dec 24, 2024
cb2efb3
Remove Assert; test using LoadContext instead of RemoteExecutor
steveharter Jan 15, 2025
e8cbf27
Remove Asserts and padding
steveharter Feb 14, 2025
306bfb8
Remove unnecessary using statement
steveharter Feb 14, 2025
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7 changes: 1 addition & 6 deletions ...raries/System.Reflection.Emit/tests/PersistedAssemblyBuilder/AssemblySaveResourceTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -53,10 +53,7 @@ public void ManagedResources(byte[] byteValue, string byteValueExpected)

// Create a temporary assembly.
string tempFilePath = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName() + ".dll");
using (FileStream fileStream = new FileStream(tempFilePath, FileMode.Create, FileAccess.Write))
{
blob.WriteContentTo(fileStream);
}
using TempFile file = new TempFile(tempFilePath, blob.ToArray());

// In order to verify the resources work with ResourceManager, we need to load the assembly.
using (RemoteInvokeHandle remoteHandle = RemoteExecutor.Invoke(static (tempFilePath, byteValue, byteValueExpected) =>
Expand Down Expand Up @@ -88,8 +85,6 @@ void Verify(IDictionaryEnumerator resources)
Assert.False(resources.MoveNext());
}
}, tempFilePath, BitConverter.ToString(byteValue), byteValueExpected)) { }

File.Delete(tempFilePath);
}
}
}
2 changes: 1 addition & 1 deletion ...raries/System.Reflection.Metadata/src/System/Reflection/Metadata/Ecma335/MetadataSizes.cs
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Expand Up @@ -12,7 +12,7 @@ namespace System.Reflection.Metadata.Ecma335
/// </summary>
public sealed class MetadataSizes
{
private const int StreamAlignment = 4;
internal const int StreamAlignment = 4;

// Call the length of the string (including the terminator) m (we require m <= 255);
internal const int MaxMetadataVersionByteCount = 0xff - 1;
Expand Down
21 changes: 12 additions & 9 deletions ...System.Reflection.Metadata/src/System/Reflection/PortableExecutable/ManagedTextSection.cs
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Expand Up @@ -4,6 +4,7 @@
using System.Diagnostics;
using System.Reflection.Internal;
using System.Reflection.Metadata;
using System.Reflection.Metadata.Ecma335;

namespace System.Reflection.PortableExecutable
{
Expand Down Expand Up @@ -40,8 +41,8 @@ internal sealed class ManagedTextSection
public int MetadataSize { get; }

/// <summary>
/// The size of managed resource data stream.
/// Aligned to <see cref="ManagedResourcesDataAlignment"/>.
/// The size of managed resource data stream (unaligned).
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@tmat Could you please take a look at the changes in this file? How are the alignment requirements expected to be handled by ManagedPEBuilder?

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ping @tmat

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@tmat tmat Jan 13, 2025 •
edited
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I don't remember what the expectations were. It's been a while.

To me it looks like we should have checked the alignments in ManagedPEBuilder constructor and throw if they are off. Can we add that check? It would break someone who emits unaligned data, but if they do the emitted assembly would be bad anyways.

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There are basically two choices: throw if not aligned or align it for the user.

This PR takes the path of aligning it for the user like we do in other areas:

If we don't align it for the user, the user would need an extra LOC to do the alignment for the somewhat common case of using resources, and that extra LOC that would be needed is not obvious to the caller.

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but if they do the emitted assembly would be bad anyways.

I don't believe the lack of alignment breaks anything, unless there is some platform-specific alignment limitations that I'm not aware of -- e.g. the test added here worked before the alignment was added.

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I'm not sure I follow. If the alignment is not needed then why are we adding it?

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There was an Assert that was failing so we either need to remove it or add the alignment \ padding. Since there was a ManagedResourcesDataAlignment public const I decided to use that (it wasn't used before). Finally, the assert was checking if alignment to 4 while the public const is 8.

I do not know why the const was added, or why the alignment and checks are there in part. Git history shows this existed 8+ years ago as part of large commits. Likely the alignment was added for efficiency when reading the subsequent data. The code may have assumed the caller would align the data, but if so then the code should have thrown and not just asserted.

/// When written, will be aligned to <see cref="ManagedResourcesDataAlignment"/>.
/// </summary>
public int ResourceDataSize { get; }

Expand Down Expand Up @@ -147,14 +148,16 @@ public int CalculateOffsetToMappedFieldDataStream()

internal int ComputeOffsetToDebugDirectory()
{
Debug.Assert(MetadataSize % 4 == 0);
Debug.Assert(ResourceDataSize % 4 == 0);
Debug.Assert(MetadataSize % MetadataSizes.StreamAlignment == 0);

return
int offset =
ComputeOffsetToMetadata() +
MetadataSize +
ResourceDataSize +
BitArithmetic.Align(ResourceDataSize, ManagedResourcesDataAlignment) +
StrongNameSignatureSize;

Debug.Assert(offset % MetadataSizes.StreamAlignment == 0);
return offset;
}

private int ComputeOffsetToImportTable()
Expand Down Expand Up @@ -254,7 +257,6 @@ public void Serialize(
Debug.Assert(ilBuilder.Count == ILStreamSize);
Debug.Assert((mappedFieldDataBuilderOpt?.Count ?? 0) == MappedFieldDataSize);
Debug.Assert((resourceBuilderOpt?.Count ?? 0) == ResourceDataSize);
Debug.Assert((resourceBuilderOpt?.Count ?? 0) % 4 == 0);

// TODO: avoid recalculation
int importTableRva = GetImportTableDirectoryEntry(relativeVirtualAddess).RelativeVirtualAddress;
Expand All @@ -278,6 +280,7 @@ public void Serialize(
if (resourceBuilderOpt != null)
{
builder.LinkSuffix(resourceBuilderOpt);
builder.Align(ManagedTextSection.ManagedResourcesDataAlignment);
}

// strong name signature:
Expand Down Expand Up @@ -387,7 +390,7 @@ private void WriteCorHeader(BlobBuilder builder, int textSectionRva, int entryPo

int metadataRva = textSectionRva + ComputeOffsetToMetadata();
int resourcesRva = metadataRva + MetadataSize;
int signatureRva = resourcesRva + ResourceDataSize;
int signatureRva = resourcesRva + BitArithmetic.Align(ResourceDataSize, ManagedResourcesDataAlignment);

int start = builder.Count;

Expand All @@ -410,7 +413,7 @@ private void WriteCorHeader(BlobBuilder builder, int textSectionRva, int entryPo

// ResourcesDirectory:
builder.WriteUInt32((uint)(ResourceDataSize == 0 ? 0 : resourcesRva)); // 28
builder.WriteUInt32((uint)ResourceDataSize);
builder.WriteUInt32((uint)BitArithmetic.Align(ResourceDataSize, ManagedResourcesDataAlignment));

// StrongNameSignatureDirectory:
builder.WriteUInt32((uint)(StrongNameSignatureSize == 0 ? 0 : signatureRva)); // 36
Expand Down
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