[cDAC] Implement SetCompilerFlags for cDAC

[barosiak]

Summary

Implement SetCompilerFlags in cDAC DacDbiImpl using ILoader contract to set debugger assembly control flags.

Changes

• DacDbiImpl.cs - SetCompilerFlags implementation
• CorDbHResults.cs - Add CORDBG_S_NOT_ALL_BITS_SET success HRESULT
• Loader contract - Add DACF_IGNORE_PDBS flag and EncCapable module flag
• ProfControlBlock - Expose MainProfilerProfInterface and NotificationProfilerCount fields (data descriptors + docs)
• DacDbiImplTests.cs - Add 8 test cases covering both flags set/unset, EnC precondition failures (not capable, no PDBs ignored, profiler present), and JIT opts toggling across architectures

[Copilot]

Pull request overview

Implements SetCompilerFlags in the cDAC DacDbiImpl using the ILoader contract to update debugger assembly control flags and adds coverage/tests and a missing success HRESULT constant to match native DAC semantics.

Changes:

• Implement DacDbiImpl.SetCompilerFlags via ILoader and return CORDBG_S_NOT_ALL_BITS_SET when EnC cannot be enabled.
• Add CORDBG_S_NOT_ALL_BITS_SET to CorDbgHResults.
• Add SetCompilerFlagsTests covering flag set/unset and EnC capability behavior across architectures.

Reviewed changes

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

File	Description
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/Dbi/DacDbiImpl.cs	Adds SetCompilerFlags implementation using ILoader and post-write EnC enablement check
src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/CorDbHResults.cs	Adds missing CORDBG_S_NOT_ALL_BITS_SET HRESULT constant
src/native/managed/cdac/tests/LoaderTests.cs	Adds new test coverage for SetCompilerFlags behavior

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.

[barosiak]

/ba-g unrelated failures and style fix, no need to re-run

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

[github-actions]

🤖 Copilot Code Review — PR #127244

Note

This review was generated by Copilot and reflects an automated analysis. Multi-model review used: Claude Opus 4.6 (primary) + Claude Sonnet 4.5 (secondary). A GPT-5.3-Codex agent was also launched but did not complete within the timeout window.

Holistic Assessment

Motivation: This PR replaces several legacy DAC delegation stubs in DacDbiImpl with contract-based implementations — part of the ongoing cDAC migration effort. The implementations for SetCompilerFlags, GetCompilerFlags, GetModuleData, IsModuleMapped, and IsDiagnosticsHiddenOrLCGMethod are all well-motivated and follow the established cDAC pattern.

Approach: The approach is sound. Each method follows the cDAC pattern: try-catch for HResult conversion, use of contracts (ILoader, IRuntimeTypeSystem), and #if DEBUG legacy validation. The TryGetPEImage refactoring properly deduplicates code. The IsMapped Webcil fix, DACF_IGNORE_PDBS addition, and loader heap traversal APIs are logical supporting changes.

Summary: ✅ LGTM. The implementations correctly match their native C++ counterparts. I verified SetCompilerFlags against DacDbiInterfaceImpl::SetCompilerFlags/CanSetEnCBits, GetCompilerFlags against the native's AreJITOptimizationsDisabled/IsEditAndContinueEnabled, and IsDiagnosticsHiddenOrLCGMethod against IsDiagnosticsHidden/IsLCGMethod. All match. Test coverage is solid for the core SetCompilerFlags logic with 8 test cases covering the key scenarios. Two minor observations below.

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Detailed Findings

✅ SetCompilerFlags — Correct match to native logic

Verified against dacdbiimpl.cpp:767-813. The cDAC faithfully reproduces the native behavior:

• Clears DACF_ALLOW_JIT_OPTS and DACF_ENC_ENABLED, masks with DACF_CONTROL_FLAGS_MASK
• The canSetEnC check matches CanSetEnCBits(): EncCapable + !CORProfilerPresent + fIgnorePdbs
• CORProfilerPresent() gracefully handles missing ProfilerControlBlock global (profiling not supported), matching #ifdef PROFILING_SUPPORTED_DATA in native
• BOOL parameter handling (!= Interop.BOOL.FALSE) correctly follows the recommended pattern for COM BOOL interop

One sub-agent flagged the exception handler overwriting hr = CORDBG_S_NOT_ALL_BITS_SET if SetDebuggerInfoBits throws. I evaluated this and it is not a bug — the native code has identical behavior (the EX_CATCH_HRESULT(hr) macro would similarly overwrite hr), and if the flag write fails, the error should indeed take precedence over the warning.

✅ GetCompilerFlags — Semantics match native

The native reads AreJITOptimizationsDisabled() (checks IS_JIT_OPTIMIZATION_DISABLED module flag) and IsEditAndContinueEnabled() (checks IS_EDIT_AND_CONTINUE module flag). The cDAC reads ModuleFlags.JitOptimizationDisabled and ModuleFlags.EditAndContinue respectively — these map to the same underlying bits. The inversion of JIT opts (Disabled == 0 → AllowJITOpts = TRUE) is correct.

✅ IsDiagnosticsHiddenOrLCGMethod — Logic correctly handles ordering

The native IsDiagnosticsHidden() = IsILStub() || IsAsyncThunkMethod() || IsWrapperStub(), and IsLCGMethod() = IsDynamicMethod() && !IsILStub(). The cDAC checks these in the same priority order, so the else if (IsDynamicMethod) branch naturally excludes IL stubs. Correct.

✅ IsModuleMapped — Matches native S_FALSE/S_OK semantics

The native (dacdbiimpl.cpp:4170-4192) defaults to S_FALSE, returning S_OK only when HasLoadedPEImage() is true. The cDAC mirrors this with TryGetLoadedImageContents as the equivalent check. The IsMapped Webcil fix (Format == Webcil → false) is also correct.

✅ TryGetPEImage refactoring — Clean deduplication

The extracted TryGetPEImage helper eliminates the duplicated PEAssembly→PEImage traversal from TryGetLoadedImageContents, IsModuleMapped, and IsProbeExtensionResultValid. Good use of [NotNullWhen(true)].

✅ EnumerateThreads signature improvement

Changing nint fpCallback to delegate* unmanaged<ulong, nint, void> fpCallback improves type safety and eliminates the manual cast. The null check for fpCallback is a good addition.

💡 CORProfilerPresent — String literals for field names

CORProfilerPresent() uses string literals "MainProfilerProfInterface" and "NotificationProfilerCount" instead of nameof(Data.ProfControlBlock.MainProfilerProfInterface). While functional, using nameof would catch field renames at compile time. This is a minor consistency point — other code in DacDbiImpl uses string literals in similar contexts, so this follows existing convention.

💡 Test coverage — Minor gaps for non-SetCompilerFlags methods

The new DacDbiImplTests.cs has excellent coverage for SetCompilerFlags (8 test cases including profiler blocking, EnC capability, and JIT opts toggling) and GetCompilerFlags (5 data-driven cases). IsModuleMapped has Loader-level tests in LoaderTests.cs. The GetModuleData and IsDiagnosticsHiddenOrLCGMethod implementations don't have DacDbi-level tests, though they do have #if DEBUG legacy validation blocks. These could be follow-up additions.

Generated by Code Review for issue #127244 · ◷

[barosiak]

/ba-g unrelated failures and style fix, no need to re-run