Implement ISOSDacInterface::GetLoaderAllocatorHeapNames and GetLoaderAllocatorHeaps in cDAC SOSDacImpl by Copilot · Pull Request #124818 · dotnet/runtime

Copilot · 2026-02-24T20:24:35Z

Description

Implements ISOSDacInterface13.GetLoaderAllocatorHeapNames and ISOSDacInterface13.GetLoaderAllocatorHeaps in the managed cDAC SOSDacImpl.cs, replacing the legacy DAC delegation stubs. Based on ClrDataAccess::GetLoaderAllocatorHeapNames and ClrDataAccess::GetLoaderAllocatorHeaps in request.cpp.

Native Data Descriptors

Added heap fields to cdac_data<LoaderAllocator> in loaderallocator.hpp: StaticsHeap, ExecutableHeap, FixupPrecodeHeap (#ifdef HAS_FIXUP_PRECODE), NewStubPrecodeHeap (#ifndef FEATURE_PORTABLE_ENTRYPOINTS), DynamicHelpersStubHeap (FEATURE_READYTORUN && FEATURE_STUBPRECODE_DYNAMIC_HELPERS), VirtualCallStubManager
Added new cdac_data<VirtualCallStubManager> in virtualcallstub.h: IndcellHeap (unconditional), CacheEntryHeap (#ifdef FEATURE_VIRTUAL_STUB_DISPATCH)
Added corresponding entries to datadescriptor.inc with matching feature guards
Added VirtualCallStubManager to DataType enum
Added #include "virtualcallstub.h" to datadescriptor.h so cdac_data<VirtualCallStubManager> is visible when datadescriptor.inc is compiled

Managed Data Classes

Updated Data/LoaderAllocator.cs with optional heap fields (FixupPrecodeHeap, NewStubPrecodeHeap, DynamicHelpersStubHeap as nullable) and always-present fields (StaticsHeap, ExecutableHeap, VirtualCallStubManager)
Created Data/VirtualCallStubManager.cs with IndcellHeap and optional CacheEntryHeap

ILoader Contract

Added single GetLoaderAllocatorHeaps(TargetPointer) method to ILoader interface returning IReadOnlyDictionary<string, TargetPointer> — dictionary keys are heap names, values are heap pointers
Implemented in Loader_1.cs with dynamic dictionary building based on data descriptor field presence via ContainsKey checks, matching the native #ifdef conditional compilation
Dictionary keys use nameof(Data.LoaderAllocator.X) and nameof(Data.VirtualCallStubManager.X) instead of hardcoded strings
Feature-conditional heaps (FixupPrecodeHeap, NewStubPrecodeHeap, DynamicHelpersStubHeap) are only included when the data descriptor field exists
VirtualCallStubManager heaps (IndcellHeap, CacheEntryHeap) are excluded entirely when VirtualCallStubManager is null

SOSDacImpl

GetLoaderAllocatorHeapNames: Queries global loader allocator via ILoader.GetLoaderAllocatorHeaps to get heap names from dictionary keys. Lazily initializes ANSI string pointers via Marshal.StringToHGlobalAnsi, cached on the instance. Standard cDAC pattern with try/catch, S_FALSE when buffer is insufficient, #if DEBUG legacy count comparison
GetLoaderAllocatorHeaps: Reads heap pointers through the ILoader contract dictionary, fills LoaderHeapKindNormal for all heaps

Tests

8 test methods in LoaderTests.cs × 4 architectures = 32 new test cases
- GetLoaderAllocatorHeapNames: Count query, full name retrieval, insufficient buffer, null pNeeded
- GetLoaderAllocatorHeaps: Count query, full heap retrieval, insufficient buffer, null address
All 864 cDAC tests pass (832 existing + 32 new)

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Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

max-charlamb · 2026-02-24T20:56:17Z

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/SOSDacImpl.cs

+    private static readonly string[] s_loaderAllocatorHeapNames =
+    [
+        "LowFrequencyHeap",
+        "HighFrequencyHeap",
+        "StaticsHeap",
+        "StubHeap",
+        "ExecutableHeap",
+        "FixupPrecodeHeap",
+        "NewStubPrecodeHeap",
+        "IndcellHeap",
+        "CacheEntryHeap",
+    ];
+
+    private static readonly nint[] s_loaderAllocatorHeapNamePtrs = InitializeHeapNamePtrs();
+
+    private static nint[] InitializeHeapNamePtrs()
+    {
+        nint[] ptrs = new nint[s_loaderAllocatorHeapNames.Length];
+        for (int i = 0; i < s_loaderAllocatorHeapNames.Length; i++)
+        {
+            ptrs[i] = Marshal.StringToHGlobalAnsi(s_loaderAllocatorHeapNames[i]);
+        }
+        return ptrs;
+    }
+
    int ISOSDacInterface13.GetLoaderAllocatorHeapNames(int count, char** ppNames, int* pNeeded)
-        => _legacyImpl13 is not null ? _legacyImpl13.GetLoaderAllocatorHeapNames(count, ppNames, pNeeded) : HResults.E_NOTIMPL;
+    {


@copilot , this is not quite correct. If you look at the runtime implementation, there are #defines that remove some elements from the list under certain conditions. We will need to do something similar here.

While we are at it, lets expand the scope of this PR to include implementing GetLoaderAllocatorHeaps is SOSDacImpl.cs since they are very related.

dotnet-policy-service · 2026-02-24T20:57:40Z

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Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

max-charlamb · 2026-02-24T21:18:01Z

@copilot, try again

…dd missing using Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

Copilot · 2026-02-24T21:29:19Z

@copilot, try again

Implementation reworked in commits up to 0554c43. Changes:

Feature-conditional heap names: GetLoaderAllocatorHeapNames in Loader_1.cs dynamically builds the names list by checking ContainsKey on the data descriptor fields - DynamicHelpersStubHeap is conditional on FEATURE_READYTORUN && FEATURE_STUBPRECODE_DYNAMIC_HELPERS, and CacheEntryHeap is conditional on FEATURE_VIRTUAL_STUB_DISPATCH, matching the native LoaderAllocatorLoaderHeapNames array.

GetLoaderAllocatorHeaps: Fully implemented in SOSDacImpl.cs, reading heap pointers through the ILoader contract. The contract reads from LoaderAllocator and VirtualCallStubManager data classes, handling null VcsManager by padding with TargetPointer.Null.

Native data descriptors: Added cdac_data<LoaderAllocator> fields (StaticsHeap, ExecutableHeap, FixupPrecodeHeap, NewStubPrecodeHeap, DynamicHelpersStubHeap, VirtualCallStubManager) and new cdac_data<VirtualCallStubManager> (IndcellHeap, CacheEntryHeap) in loaderallocator.hpp, virtualcallstub.h, and datadescriptor.inc.

Tests: 32 new test cases (8 test methods × 4 architectures) covering both methods. All 864 cDAC tests pass.

max-charlamb

@copilot , address feedback

max-charlamb · 2026-02-24T21:44:20Z

...tive/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/ILoader.cs

+    IReadOnlyList<string> GetLoaderAllocatorHeapNames() => throw new NotImplementedException();
+    IReadOnlyList<TargetPointer> GetLoaderAllocatorHeaps(TargetPointer loaderAllocatorPointer) => throw new NotImplementedException();


Instead of hardcoding these, lets have a single API that returns a dictionary. If the ISOSDacInterface APIs only want the names, we can query the global loader allocator and return the values. That way we don't care about ordering.

…ps API Replace separate GetLoaderAllocatorHeapNames() and GetLoaderAllocatorHeaps(TargetPointer) with a single GetLoaderAllocatorHeaps(TargetPointer) returning IReadOnlyDictionary<string, TargetPointer>. SOSDacImpl.GetLoaderAllocatorHeapNames now queries the global loader allocator to get names from the dictionary. GetLoaderAllocatorHeaps iterates dictionary values. Tests updated to use dictionary-based mock and verify unordered name/address sets. Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

max-charlamb

@copilot , address feedback

...native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/Loader_1.cs

…tionary - Use nameof(Data.LoaderAllocator.X) instead of hardcoded strings for all dictionary keys in GetLoaderAllocatorHeaps - Make FixupPrecodeHeap and NewStubPrecodeHeap conditional on ContainsKey (exclude from dictionary when field absent from data descriptor) - Remove else branch that padded IndcellHeap/CacheEntryHeap with null when VirtualCallStubManager is null - only include them when VcsManager exists - All 864 cDAC tests pass Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

Copilot · 2026-02-24T22:05:53Z

@copilot , address feedback

Addressed all three review comments in e0e9cd5 — nameof for dict keys, conditional inclusion for FixupPrecodeHeap/NewStubPrecodeHeap, and no null-padding for VcsManager heaps. All 864 tests pass.

@copilot, try again

Addressed all three review comments in e0e9cd5 — nameof for dict keys, conditional inclusion for FixupPrecodeHeap/NewStubPrecodeHeap, and no null-padding for VcsManager heaps. All 864 tests pass.

max-charlamb · 2026-02-24T22:37:27Z

@copilot , please fix build break

datadescriptor.h did not include virtualcallstub.h, so the cdac_data<VirtualCallStubManager> template specialization was not visible when datadescriptor.inc was compiled. This caused a build failure referencing cdac_data<VirtualCallStubManager>::IndcellHeap and cdac_data<VirtualCallStubManager>::CacheEntryHeap. Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

Copilot · 2026-02-24T22:46:39Z

@copilot , please fix build break

Fixed in 3f63f2f. The issue was that datadescriptor.h did not include virtualcallstub.h, so cdac_data<VirtualCallStubManager> was not visible when datadescriptor.inc was compiled. Added #include "virtualcallstub.h" to datadescriptor.h.

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noahfalk · 2026-02-25T12:06:32Z

...tive/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/ILoader.cs

    TargetPointer GetDynamicIL(ModuleHandle handle, uint token) => throw new NotImplementedException();
-    IReadOnlyList<string> GetLoaderAllocatorHeapNames() => throw new NotImplementedException();
-    IReadOnlyList<TargetPointer> GetLoaderAllocatorHeaps(TargetPointer loaderAllocatorPointer) => throw new NotImplementedException();
+    IReadOnlyDictionary<string, TargetPointer> GetLoaderAllocatorHeaps(TargetPointer loaderAllocatorPointer) => throw new NotImplementedException();


I don't see any docs for this in the contract doc. I assume we need to add it.

Initial plan

d9025a1

Copilot AI assigned Copilot and max-charlamb Feb 24, 2026

Copilot started work on behalf of max-charlamb February 24, 2026 20:24 View session

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Copilot AI and others added 2 commits February 24, 2026 20:45

Implement GetLoaderAllocatorHeapNames in SOSDacImpl and add unit tests

1b5c756

Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

Remove unused hrLocal variable in DEBUG block

5cd00b4

Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Implement GetLoaderAllocatorHeapNames in SOSDacImpl.cs~~ Implement ISOSDacInterface::GetLoaderAllocatorHeapNames in cDAC SOSDacImpl Feb 24, 2026

Copilot finished work on behalf of max-charlamb February 24, 2026 20:51

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Changes before error encountered

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Co-authored-by: max-charlamb <44248479+max-charlamb@users.noreply.github.com>

Copilot started work on behalf of max-charlamb February 24, 2026 21:18 View session

Remove fragile try-catch for VirtualCallStubManager type lookup and a…

0554c43

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Copilot AI changed the title ~~Implement ISOSDacInterface::GetLoaderAllocatorHeapNames in cDAC SOSDacImpl~~ Implement ISOSDacInterface::GetLoaderAllocatorHeapNames and GetLoaderAllocatorHeaps in cDAC SOSDacImpl Feb 24, 2026

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		IReadOnlyList<string> GetLoaderAllocatorHeapNames() => throw new NotImplementedException();
		IReadOnlyList<TargetPointer> GetLoaderAllocatorHeaps(TargetPointer loaderAllocatorPointer) => throw new NotImplementedException();

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Description

Native Data Descriptors

Managed Data Classes

ILoader Contract

SOSDacImpl

Tests

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