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Merge remote-tracking branch 'upstream/main' into interlockedgeneric
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‎docs/design/datacontracts/DacStreams.md

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# Contract DacStreams
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This contract is for getting information from the streams embedded into a dump file as it crashes
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## APIs of contract
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``` csharp
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// Return string corresponding to type system data structure if it exists, or null otherwise
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string StringFromEEAddress(TargetPointer address);
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```
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## Version 1
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Global variables used
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| Global Name | Type | Purpose |
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| --- | --- | --- |
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| MiniMetaDataBuffAddress | TargetPointer | Identify where the mini metadata stream exists |
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| MiniMetaDataBuffMaxSize | uint | Identify where the size of the mini metadata stream |
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Magic numbers
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| Name | Value |
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| --- | --- |
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| MiniMetadataSignature | 0x6d727473 |
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| EENameStreamSignature | 0x614e4545 |
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The format of the MiniMetadataStream begins with a Streams header, which has 3 fields
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| Field | Type | Offset | Meaning |
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| --- | --- | --- | --- |
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| MiniMetadataSignature| uint | 0 | Magic value used to identify that there are streams |
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| TotalSize | uint | 4 | Total size of the entire set of MiniMetadata streams including this header |
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| Count of Streams | uint | 8 | Number of streams in the MiniMetadata |
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The concept is that each stream simply follows the previous stream in the buffer.
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There is no padding, so the data is not expected to be aligned within the buffer.
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NOTE: At the moment there is only 1 supported stream type, so Count of Streams can only be 1.
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The `EENameStream` is structured as a header, plus a series of null-terminated utf8 strings, and pointers.
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The EENameStream header
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| Field | Type | Offset | Meaning |
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| --- | --- | --- | --- |
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| EENameStreamSignature | uint | 0 | Magic value used to identify that the bytes immediately following are an `EENameStream` |
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| CountOfNames | uint | 4 | Number of names encoded |
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EENameStream entry
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| Field | Type | Offset | Meaning |
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| --- | --- | --- | --- |
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| Pointer | pointer | 0 | Pointer to type system structure |
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| String | null-terminated UTF-8 sting | 4 or 8 based on target pointer size | Pointer to type system structure |
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Following the EENameStream header, there are CountOfNames entries. Each entry begins with a target pointer sized block which identifies a particular type system data structure, followed by a utf8 encoded null-terminated string.
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``` csharp
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string StringFromEEAddress(TargetPointer address)
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{
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TargetPointer miniMetaDataBuffAddress = _target.Read<uint>(_target.ReadGlobalPointer(Constants.Globals.MiniMetaDataBuffAddress));
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uint miniMetaDataBuffMaxSize = _target.Read<uint>(_target.ReadGlobalPointer(Constants.Globals.MiniMetaDataBuffMaxSize));
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// Parse MiniMetadataStream according the the format described above to produce a dictionary from pointer to string from the EENameStream.
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// Then lookup in the dictionary, to produce a result if it was present in the table.
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// In general, since this api is intended for fallback scenarios, implementations of this api should attempt
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// to return null instead of producing errors.
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// Since in normal execution of the runtime no stream is constructed, it is normal when examining full dumps and live process state without a stream encoded.
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}
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```

‎docs/design/datacontracts/Loader.md

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@@ -26,6 +26,75 @@ record struct ModuleLookupTables(
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TargetPointer MethodDefToDesc,
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TargetPointer TypeDefToMethodTable,
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TargetPointer TypeRefToMethodTable);
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internal struct EcmaMetadataSchema
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{
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public EcmaMetadataSchema(string metadataVersion, bool largeStringHeap, bool largeBlobHeap, bool largeGuidHeap, int[] rowCount, bool[] isSorted, bool variableSizedColumnsAre4BytesLong)
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{
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MetadataVersion = metadataVersion;
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LargeStringHeap = largeStringHeap;
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LargeBlobHeap = largeBlobHeap;
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LargeGuidHeap = largeGuidHeap;
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_rowCount = rowCount;
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_isSorted = isSorted;
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VariableSizedColumnsAreAll4BytesLong = variableSizedColumnsAre4BytesLong;
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}
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public readonly string MetadataVersion;
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public readonly bool LargeStringHeap;
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public readonly bool LargeBlobHeap;
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public readonly bool LargeGuidHeap;
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// Table data, these structures hold MetadataTable.Count entries
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private readonly int[] _rowCount;
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public readonly ReadOnlySpan<int> RowCount => _rowCount;
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private readonly bool[] _isSorted;
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public readonly ReadOnlySpan<bool> IsSorted => _isSorted;
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// In certain scenarios the size of the tables is forced to be the maximum size
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// Otherwise the size of columns should be computed based on RowSize/the various heap flags
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public readonly bool VariableSizedColumnsAreAll4BytesLong;
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}
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internal class TargetEcmaMetadata
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{
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public TargetEcmaMetadata(EcmaMetadataSchema schema,
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TargetSpan[] tables,
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TargetSpan stringHeap,
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TargetSpan userStringHeap,
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TargetSpan blobHeap,
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TargetSpan guidHeap)
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{
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Schema = schema;
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_tables = tables;
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StringHeap = stringHeap;
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UserStringHeap = userStringHeap;
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BlobHeap = blobHeap;
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GuidHeap = guidHeap;
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}
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public EcmaMetadataSchema Schema { get; init; }
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private TargetSpan[] _tables;
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public ReadOnlySpan<TargetSpan> Tables => _tables;
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public TargetSpan StringHeap { get; init; }
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public TargetSpan UserStringHeap { get; init; }
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public TargetSpan BlobHeap { get; init; }
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public TargetSpan GuidHeap { get; init; }
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}
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[Flags]
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internal enum AvailableMetadataType
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{
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None = 0,
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ReadOnly = 1,
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ReadWriteSavedCopy = 2,
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ReadWrite = 4
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}
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```
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``` csharp
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TargetPointer GetThunkHeap(ModuleHandle handle);
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TargetPointer GetILBase(ModuleHandle handle);
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TargetPointer GetMetadataAddress(ModuleHandle handle, out ulong size);
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AvailableMetadataType GetAvailableMetadataType(ModuleHandle handle);
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TargetPointer GetReadWriteSavedMetadataAddress(ModuleHandle handle, out ulong size);
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TargetEcmaMetadata GetReadWriteMetadata(ModuleHandle handle);
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ModuleLookupTables GetLookupTables(ModuleHandle handle);
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```
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## Version 1
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Data descriptors used:
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- `Module`
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| Data Descriptor Name | Field | Meaning |
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| --- | --- | --- |
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| `Module` | `Assembly` | Assembly of the Module |
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| `Module` | `Base` | Pointer to start of PE file in memory |
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| `Module` | `Flags` | Assembly of the Module |
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| `Module` | `LoaderAllocator` | LoaderAllocator of the Module |
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| `Module` | `ThunkHeap` | Pointer to the thunk heap |
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| `Module` | `DynamicMetadata` | Pointer to saved metadata for reflection emit modules |
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| `Module` | `FieldDefToDescMap` | Mapping table |
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| `Module` | `ManifestModuleReferencesMap` | Mapping table |
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| `Module` | `MemberRefToDescMap` | Mapping table |
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| `Module` | `MethodDefToDescMap` | Mapping table |
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| `Module` | `TypeDefToMethodTableMap` | Mapping table |
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| `Module` | `TypeRefToMethodTableMap` | Mapping table |
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| `DynamicMetadata` | `Size` | Size of the dynamic metadata blob (as a 32bit uint) |
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| `DynamicMetadata` | `Data` | Start of dynamic metadata data array |
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``` csharp
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ModuleHandle GetModuleHandle(TargetPointer modulePointer)
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return baseAddress + rva;
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}
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AvailableMetadataType ILoader.GetAvailableMetadataType(ModuleHandle handle)
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{
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Data.Module module = _target.ProcessedData.GetOrAdd<Data.Module>(handle.Address);
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AvailableMetadataType flags = AvailableMetadataType.None;
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TargetPointer dynamicMetadata = target.ReadPointer(handle.Address + /* Module::DynamicMetadata offset */);
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if (dynamicMetadata != TargetPointer.Null)
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flags |= AvailableMetadataType.ReadWriteSavedCopy;
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else
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flags |= AvailableMetadataType.ReadOnly;
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return flags;
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}
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TargetPointer ILoader.GetReadWriteSavedMetadataAddress(ModuleHandle handle, out ulong size)
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{
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Data.Module module = _target.ProcessedData.GetOrAdd<Data.Module>(handle.Address);
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TargetPointer dynamicMetadata = target.ReadPointer(handle.Address + /* Module::DynamicMetadata offset */);
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size = target.Read<uint>(handle.Address + /* DynamicMetadata::Size offset */);
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TargetPointer result = handle.Address + /* DynamicMetadata::Data offset */;
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return result;
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}
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ModuleLookupTables GetLookupTables(ModuleHandle handle)
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{
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return new ModuleLookupTables(

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