[DAC] Properly dereference internal_root_array

[max-charlamb]

Found while working on #119324

GetHeapAnalyzeStaticData is inconsistent with its pair GetHeapAnalyzeData. The former returns a uint8_t*** whereas the latter returns a uint8_t**. I checked the usage of these APIs in clrmd and it expects both to return the same format.

// gcpriv.h - declaration
class gc_heap
{
    ...
    PER_HEAP_FIELD_DIAG_ONLY uint8_t** internal_root_array;
    PER_HEAP_FIELD_DIAG_ONLY size_t internal_root_array_index;
    PER_HEAP_FIELD_DIAG_ONLY BOOL heap_analyze_success;
    ...
}

// gc.cpp
PopulateDacVars(...)
{
    ...
    gcDacVars->internal_root_array = &gc_heap::internal_root_array;
    gcDacVars->internal_root_array_index = &gc_heap::internal_root_array_index;
    gcDacVars->heap_analyze_success = &gc_heap::heap_analyze_success;
    ...
}

I modified GetHeapAnalyzeStaticData to dereference the g_gcDacGlobals->internal_root_array matching GetHeapAnalyzeData.

dotnet/diagnostics#5562 adds a test FindRootsOlderGeneration which verifies this behaves correctly. The test fails in the current main branch.
Pipeline with fixes: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1143226&view=results

[Copilot]

Pull Request Overview

This PR fixes a data access consistency issue in the DAC (Data Access Component) by properly dereferencing the internal_root_array pointer in GetHeapAnalyzeStaticData. The change ensures that both GetHeapAnalyzeStaticData and GetHeapAnalyzeData return the same data format (uint8_t** instead of uint8_t***), which is expected by external tools like ClrMD.

• Adds proper dereferencing of g_gcDacGlobals->internal_root_array to match the expected return type
• Ensures consistency between GetHeapAnalyzeStaticData and GetHeapAnalyzeData APIs
• Fixes compatibility with external diagnostic tools that expect uniform data formats

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[noahfalk]

👍

[max-charlamb]

/ba-g test failures unrelated to DAC change

[max-charlamb]

/backport to release/10.0

[github-actions]

Started backporting to release/10.0: https://github.com/dotnet/runtime/actions/runs/17588280032