[cDAC] Implement GetContext and GetAppDomain on ClrDataFrame by max-charlamb · Pull Request #125064 · dotnet/runtime

max-charlamb · 2026-03-02T18:00:49Z

Summary

Implement GetContext and GetAppDomain on the managed ClrDataFrame (IXCLRDataFrame), replacing the legacy-only delegation with native cDAC implementations that match the behavior of the native stack.cpp implementations.

Changes

New files

ClrDataAppDomain.cs — [GeneratedComClass] implementing IXCLRDataAppDomain with:
- GetName via the Loader contract's GetAppDomainFriendlyName()
- GetUniqueID returning 1 (CoreCLR single AppDomain, matching native DefaultADID)
- GetFlags returning 0 (CLRDATA_DOMAIN_DEFAULT)
ClrDataFrameDumpTests.cs — Dump-based integration tests organized by IXCLRDataFrame method, each selecting its own debuggee

Modified files

ClrDataFrame.cs:
- GetContext: Uses StackWalk.GetRawContext() to retrieve context bytes, with #if DEBUG validation against the legacy DAC (same pattern as ClrDataStackWalk.GetContext)
- GetAppDomain: Reads the global AppDomain pointer and returns a COM-wrapped ClrDataAppDomain using the StrategyBasedComWrappers pattern
DumpTestBase.cs: Added InitializeDumpTest(config, debuggeeName, dumpType) overload enabling per-test debuggee selection

Test Results

All 5 new tests pass (local config), 5 correctly skip (net10.0 due to InlinedCallFrame.Datum dependency), and existing tests show no regressions.

dotnet-policy-service · 2026-03-02T18:02:09Z

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Copilot

Pull request overview

Implements managed cDAC versions of IXCLRDataFrame.GetContext and IXCLRDataFrame.GetAppDomain (moving away from legacy-only delegation) and adds dump-based integration tests to validate the new behavior, including introducing a managed IXCLRDataAppDomain implementation.

Changes:

Added an InitializeDumpTest overload to allow tests to select debuggee/dump type per test.
Added new dump-based tests for IXCLRDataFrame.GetContext and GetAppDomain.
Implemented cDAC-backed ClrDataFrame.GetContext/GetAppDomain and introduced ClrDataAppDomain (IXCLRDataAppDomain) in the Legacy managed cDAC layer.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/native/managed/cdac/tests/DumpTests/DumpTestBase.cs	Adds an overload to load dumps by explicit debuggee/dump type for more flexible dump tests.
src/native/managed/cdac/tests/DumpTests/ClrDataFrameDumpTests.cs	New dump-based integration tests covering `IXCLRDataFrame.GetContext` and `GetAppDomain`.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataFrame.cs	Replaces legacy-only delegation with native-contract-backed implementations for `GetContext` and `GetAppDomain`.
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataAppDomain.cs	New managed COM class implementing `IXCLRDataAppDomain` for the AppDomain returned by `GetAppDomain`.

Implement GetContext using StackWalk.GetRawContext to retrieve context bytes from the frame handle, matching the native stack.cpp behavior. Implement GetAppDomain by reading the global AppDomain pointer and wrapping it in a new ClrDataAppDomain class that implements IXCLRDataAppDomain with GetName, GetUniqueID, and GetFlags. Add overloaded InitializeDumpTest to DumpTestBase so individual test methods can select their own debuggee and dump type. Add ClrDataFrameDumpTests with tests for GetContext (returns non-empty context, sets context size, buffer-too-small error) and GetAppDomain (returns valid AppDomain, has expected unique ID of 1). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 7 comments.

…e and add DEBUG legacy verification to GetUniqueID and GetFlags Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

ClrDataFrame.GetContext: - Fix inverted buffer validation: fail when contextBufSize < context length (buffer too small), not when buffer is too large - Copy full context.Length bytes on success instead of contextBufSize bytes (matches native DAC CopyMemory(&m_context, contextBufSize)) - Remove early return so DEBUG legacy validation block still runs - Use Debug.ValidateHResult instead of Debug.Assert for HRESULT comparison ClrDataAppDomain.GetName: - Return S_FALSE when output is truncated (bufLen < required length), matching native DAC StringCchCopy behavior (S_OK vs S_FALSE) - Use Debug.ValidateHResult for HRESULT comparison in DEBUG block - Check hr >= 0 (success) instead of hr == S_OK for nameLen validation Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…checks, test bug - ClrDataAppDomain.GetName: Catch VirtualReadException and fall back to empty string, matching SOSDacImpl.GetAppDomainName behavior. Remove redundant double-write of nameLen. - ClrDataAppDomain.GetUniqueID/GetFlags: Add null pointer checks returning E_INVALIDARG. - ClrDataFrame.GetContext DEBUG block: Fix ValidateHResult argument order (cdacHr, dacHr). - ClrDataAppDomain.GetName DEBUG block: Fix ValidateHResult argument order. - ClrDataFrameDumpTests: Fix GetContext_BufferTooSmall test - buffer was rawContext.Length+1 (too large), changed to rawContext.Length-1. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Add #if DEBUG block comparing cDAC hr vs legacy DAC hrLegacy in ClrDataFrame.GetAppDomain, matching the pattern used in GetMethodInstance and other implemented methods. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- GetUniqueID/GetFlags: Use try/catch + throw ArgumentNullException pattern instead of early-return HRESULT, matching standard cDAC method pattern. Also switch DEBUG blocks to ValidateHResult. - ClrDataFrameDumpTests: Remove unused usings, add rawContext.Length guard before subtraction. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 8 comments.

When the overloaded InitializeDumpTest is called with an explicit dumpType, EvaluateSkipAttributes now uses that value instead of the class property DumpType, so skip logic is evaluated correctly. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

Copilot

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

rcj1

LGTM!

## Summary Implement `GetContext` and `GetAppDomain` on the managed `ClrDataFrame` (IXCLRDataFrame), replacing the legacy-only delegation with native cDAC implementations that match the behavior of the native `stack.cpp` implementations. ## Changes ### New files - **`ClrDataAppDomain.cs`** — `[GeneratedComClass]` implementing `IXCLRDataAppDomain` with: - `GetName` via the Loader contract's `GetAppDomainFriendlyName()` - `GetUniqueID` returning `1` (CoreCLR single AppDomain, matching native `DefaultADID`) - `GetFlags` returning `0` (`CLRDATA_DOMAIN_DEFAULT`) - **`ClrDataFrameDumpTests.cs`** — Dump-based integration tests organized by IXCLRDataFrame method, each selecting its own debuggee --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Co-authored-by: Max Charlamb <maxcharlamb@microsoft.com>

…rDataFrame (#125463) ## [cDAC] Implement GetArgumentByIndex and GetLocalVariableByIndex on ClrDataFrame Builds on #125064 (GetContext/GetAppDomain) to add variable inspection support to the managed cDAC. ### What this PR does **DebugInfo contract (variable location resolution):** - `GetMethodVarInfo` on `IDebugInfo` for resolving native variable locations from JIT debug info - `NativeVarInfo` types (internal) with DoVars nibble decoder - `DebugVarInfo`/`DebugVarLocKind` (public stable API in Abstractions) - Register mapping for x64/x86/ARM64/ARM including REGNUM_AMBIENT_SP - Documented in `DebugInfo.md` (Version 2 section with VarLocType constants and encoding format) **SignatureDecoder contract (type resolution):** - `DecodeMethodSignature` -- decodes full method signature resolving all parameter/return types including generic instantiations (VAR, MVAR, GENERICINST) - `DecodeLocalSignature` -- reads IL method body header, finds local signature token, decodes all local variable types - `SignatureTypeProvider` updated to resolve class-level generic params (VAR) via MethodDescHandle context - Documented in `SignatureDecoder.md` **RuntimeTypeSystem contract:** - `IsEnum(TypeHandle)` -- detects enum types via GetSignatureCorElementType(ValueType) + InternalCorElementType != ValueType - `GetPrimitiveType(CorElementType)` -- returns TypeHandle for a primitive/well-known CorElementType - Documented in `RuntimeTypeSystem.md` (API section + Version 1 pseudocode) **ClrDataFrame.GetArgumentByIndex / GetLocalVariableByIndex:** - Parameter name resolution from metadata, `this` handling for instance methods - Type resolution via `ISignatureDecoder` contracts (DecodeMethodSignature/DecodeLocalSignature) - Variable location resolution via `GetMethodVarInfo` + local register/stack resolution - `MapCorElementTypeToFlags` matches native DAC's `GetTypeFieldValueFlags`: IS_PRIMITIVE, IS_VALUE_TYPE, IS_REFERENCE, IS_STRING, IS_ARRAY, IS_ENUM, IS_POINTER - ByRef unwrapping for underlying type flag resolution - Function pointer types mapped to IntPtr matching native DAC behavior (`ELEMENT_TYPE_FNPTR` under `#ifndef DACCESS_COMPILE` -> IntPtr) - Primitive size adjustment (NativeVarLocations always reports pointer-sized; shrink for actual primitive sizes) - Legacy verification with `AllowCdacSuccess` validation mode **ClrDataValue (new, implements IXCLRDataValue):** - `GetFlags`, `GetSize`, `GetBytes`, `GetAddress`, `GetNumLocations`, `GetLocationByIndex` - Legacy verification on all implemented methods - `ClrDataValueFlag` and `ClrDataVLocFlag` made public for test access **Native DAC fix:** - `REGNUM_AMBIENT_SP` handling in `GetRegOffsInCONTEXT` on AMD64 (util.cpp) ### Known Gaps (tracked as issues) - #125791 -- `ClrDataFrame.GetContext` should use `contextFlags` to compute required context size (currently always returns full platform context) - #125792 -- `GetConstructedType` cannot resolve cross-module pointer TypeDescs (pointer variables like `int*` return DEFAULT flags instead of IS_POINTER) ### Dump test scenarios `LocalVariables` debuggee with 13 frames exercising type coverage from simple to complex: | Frame | Arguments | Locals | Types Tested | Expected Flags | |-------|-----------|--------|-------------|----------------| | `PrimitiveVars` | int, double, bool, char, byte, short, long, float | int, double | I4, R8, BOOLEAN, CHAR, U1, I2, I8, R4 | IS_PRIMITIVE | | `NativeIntVars` | nint, nuint | nint, nuint | I, U | IS_PRIMITIVE (pointer-sized) | | `StructVars` | TinyStruct(1B), SmallStruct(8B), LargeStruct(32B) | SmallStruct | VALUETYPE | IS_VALUE_TYPE | | `ReferenceTypeVars` | string, class, enum, object, int[] | -- | STRING, CLASS, VALUETYPE(enum), OBJECT, SZARRAY | IS_REFERENCE, IS_ENUM | | `GenericInstAndByRefVars` | List\<int\>, KeyValuePair\<int,string\>, ref int | List\<int\> | GENERICINST+CLASS, GENERICINST+VALUETYPE, BYREF | IS_REFERENCE, IS_VALUE_TYPE, IS_PRIMITIVE (unwrapped) | | `InstanceMethodOnStruct` | SmallStruct | -- | VALUETYPE (static helper) | IS_VALUE_TYPE | | `InstanceMethodVars` | this (SimpleClass), int | int | CLASS (this), I4 | IS_REFERENCE, IS_PRIMITIVE | | `ClassGenericVars` | T (class-level VAR) | T | VAR -> instantiated type | IS_REFERENCE | | `MethodGenericVars` | T1, T2 (method-level MVAR) | T1 | MVAR -> instantiated type | IS_PRIMITIVE, IS_REFERENCE | | `SingleDimArrayVars` | int[] | int[] | SZARRAY | IS_REFERENCE | | `MultiDimArrayVars` | int[,] | int[,] | ARRAY | IS_REFERENCE | | `PointerVars` | int\*, delegate\*\<int,int\> | -- | PTR, FNPTR | IS_POINTER (gap: #125792), IS_PRIMITIVE | | `Crash` | -- | -- | (triggers dump) | -- | **IXCLRDataValueDumpTests** -- validates GetSize, GetFlags, GetBytes, GetNumLocations, GetLocationByIndex across all frames above. **IXCLRDataFrameDumpTests** -- validates GetArgumentByIndex, GetLocalVariableByIndex, GetNumArguments, GetNumLocalVariables, GetContext, GetAppDomain, GetMethodInstance. ### Validation - All dump tests pass (local runtime) - SOS tests: non-GetContext tests pass; GetContext failures are pre-existing from #125064 - cdb comparison: zero assertion failures between cDAC and legacy DAC --------- Co-authored-by: Max Charlamb <maxcharlamb@microsoft.com> Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings March 2, 2026 18:00

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max-charlamb marked this pull request as draft March 2, 2026 18:02

max-charlamb force-pushed the cdac-dataframe-apis branch from 030f5df to 92486f5 Compare March 2, 2026 18:02

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Use OutputBufferHelpers.CopyStringToBuffer in ClrDataAppDomain.GetNam…

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…e and add DEBUG legacy verification to GetUniqueID and GetFlags Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

max-charlamb force-pushed the cdac-dataframe-apis branch from afbd277 to afbc563 Compare March 6, 2026 18:23

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Max Charlamb and others added 2 commits March 6, 2026 14:51

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Comment thread src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataAppDomain.cs

Comment thread src/native/managed/cdac/tests/DumpTests/ClrDataFrameDumpTests.cs Outdated

Comment thread src/native/managed/cdac/tests/DumpTests/ClrDataFrameDumpTests.cs Outdated

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Comment thread src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataAppDomain.cs Outdated

Max Charlamb and others added 2 commits March 6, 2026 15:27

Add DEBUG validation block to GetAppDomain

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Add #if DEBUG block comparing cDAC hr vs legacy DAC hrLegacy in ClrDataFrame.GetAppDomain, matching the pattern used in GetMethodInstance and other implemented methods. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings March 6, 2026 20:45

max-charlamb force-pushed the cdac-dataframe-apis branch from afc4ac4 to 6a83195 Compare March 9, 2026 20:19

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max-charlamb requested review from hoyosjs, noahfalk and steveisok and removed request for ilonatommy and maraf March 9, 2026 20:22

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Comment thread src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataAppDomain.cs Outdated

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Comment thread src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataAppDomain.cs

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max-charlamb force-pushed the cdac-dataframe-apis branch from 12550b4 to 8f1b852 Compare March 10, 2026 15:52

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Comment thread docs/design/datacontracts/Loader.md

Comment thread src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataAppDomain.cs

Comment thread src/native/managed/cdac/tests/DumpTests/IXCLRDataFrameDumpTests.cs

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Comment thread src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataFrame.cs Outdated

address comment

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max-charlamb merged commit 3f56fbb into dotnet:main Mar 11, 2026
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max-charlamb deleted the cdac-dataframe-apis branch March 11, 2026 17:24

max-charlamb mentioned this pull request Mar 11, 2026

[cDAC] Implement GetArgumentByIndex and GetLocalVariableByIndex on ClrDataFrame #125463

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dotnet-maestro Bot mentioned this pull request Mar 12, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#5408

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max-charlamb commented Mar 2, 2026 •

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