Extract unsigned DAC registry logic into shared EnableUnsignedDac.props

Move the DisableAuxProviderSignatureCheck registry key logic into a
shared props file imported by both DumpTests.targets and
cdac-dump-helix.proj. Add /reg:32 to also set the key in the WoW64
registry view so x86 processes find it under WOW6432Node.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: max-charlamb

src/native/managed/cdac/tests/DumpTests/DumpTests.targets

@@ -62,23 +62,8 @@
     <DumpRuntimeVersion Include="$(DumpVersions)" />
   </ItemGroup>
 
-  <!--
-    On Windows, heap dumps (type 2) require the DAC (mscordaccore.dll) which is unsigned
-    in local/CI builds. Set the DisableAuxProviderSignatureCheck registry value so that
-    MiniDumpWriteDump accepts the unsigned DAC. Windows 11+ / Server 2022+ only.
-
-    This is opt-in via /p:SetDisableAuxProviderSignatureCheck=true to avoid surprising
-    machine-wide registry changes during a normal build.
-  -->
-  <Target Name="_EnableUnsignedDacWindows"
-          BeforeTargets="GenerateAllDumps"
-          Condition="'$(HostOS)' == 'windows' AND '$(SetDisableAuxProviderSignatureCheck)' == 'true'">
-    <Exec Command="reg add &quot;HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\MiniDumpSettings&quot; /v DisableAuxProviderSignatureCheck /t REG_DWORD /d 1 /f"
-          IgnoreExitCode="true"
-          IgnoreStandardErrorWarningFormat="true" />
-    <Message Text="Note: If heap dump generation fails on Windows, ensure the DisableAuxProviderSignatureCheck registry key is set. Run as admin or set manually: reg add &quot;HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\MiniDumpSettings&quot; /v DisableAuxProviderSignatureCheck /t REG_DWORD /d 1 /f"
-             Importance="normal" />
-  </Target>
+  <!-- Unsigned DAC registry key for heap dumps (shared with cdac-dump-helix.proj) -->
+  <Import Project="EnableUnsignedDac.props" />
 
   <!-- Filter out Windows-only debuggees on non-Windows platforms. Debuggees opt in
        by setting <WindowsOnly>true</WindowsOnly> in their csproj. -->

src/native/managed/cdac/tests/DumpTests/EnableUnsignedDac.props

@@ -0,0 +1,33 @@
+<Project>
+
+  <!--
+    On Windows, heap dumps (type 2) require the DAC (mscordaccore.dll) which is unsigned
+    in local/CI builds. Set the DisableAuxProviderSignatureCheck registry value so that
+    MiniDumpWriteDump accepts the unsigned DAC. Windows 11+ / Server 2022+ only.
+
+    The key must be set in both the native (64-bit) and WoW64 (32-bit) registry views.
+    Without /reg:32, x86 processes running under WoW64 read from
+    HKLM\SOFTWARE\WOW6432Node\... and miss the key, producing degraded dumps.
+  -->
+
+  <PropertyGroup>
+    <_DacRegKey>HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\MiniDumpSettings</_DacRegKey>
+    <_DacRegAdd>reg add &quot;$(_DacRegKey)&quot; /v DisableAuxProviderSignatureCheck /t REG_DWORD /d 1 /f</_DacRegAdd>
+    <_DacRegAdd32>$(_DacRegAdd) /reg:32</_DacRegAdd32>
+  </PropertyGroup>
+
+  <!--
+    MSBuild target for local/CI builds (opt-in via /p:SetDisableAuxProviderSignatureCheck=true).
+  -->
+  <Target Name="_EnableUnsignedDacWindows"
+          BeforeTargets="GenerateAllDumps"
+          Condition="'$(HostOS)' == 'windows' AND '$(SetDisableAuxProviderSignatureCheck)' == 'true'">
+    <Exec Command="$(_DacRegAdd)" IgnoreExitCode="true" IgnoreStandardErrorWarningFormat="true" />
+    <!-- WoW64 view only needed for x86 processes -->
+    <Exec Command="$(_DacRegAdd32)" IgnoreExitCode="true" IgnoreStandardErrorWarningFormat="true"
+          Condition="'$(TargetArchitecture)' == 'x86'" />
+    <Message Text="Note: If heap dump generation fails on Windows, ensure the DisableAuxProviderSignatureCheck registry key is set. Run as admin or set manually: $(_DacRegAdd)"
+             Importance="normal" />
+  </Target>
+
+</Project>

src/native/managed/cdac/tests/DumpTests/cdac-dump-helix.proj

@@ -63,6 +63,7 @@
     derived from each debuggee's DumpTypes property (Heap->heap/2, Full->full/4).
   -->
   <Import Project="$(DumpTestsPayload)/debuggee-metadata.props" />
+  <Import Project="$(MSBuildThisFileDirectory)EnableUnsignedDac.props" />
 
   <!--
     Helix work item command: generate dumps then run tests (or tar + upload).
@@ -115,7 +116,9 @@
   <!-- Pre-commands: enable dump generation -->
   <ItemGroup Condition="'$(TargetOS)' == 'windows'">
     <!-- Allow heap dump generation with the unsigned locally-built DAC -->
-    <HelixPreCommand Include="reg add &quot;HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\MiniDumpSettings&quot; /v DisableAuxProviderSignatureCheck /t REG_DWORD /d 1 /f 2&gt;nul || (echo DisableAuxProviderSignatureCheck registry write skipped &amp; exit /b 0)" />
+    <HelixPreCommand Include="$(_DacRegAdd) 2&gt;nul || (echo DisableAuxProviderSignatureCheck registry write skipped &amp; exit /b 0)" />
+    <!-- WoW64 view only needed for x86 processes -->
+    <HelixPreCommand Condition="'$(TargetArchitecture)' == 'x86'" Include="$(_DacRegAdd32) 2&gt;nul || (echo DisableAuxProviderSignatureCheck /reg:32 registry write skipped &amp; exit /b 0)" />
     <HelixPreCommand Include="set DOTNET_DbgEnableMiniDump=1" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetOS)' != 'windows'">