[cDAC] Fix GetLocalVariableCount to return E_FAIL for missing local signatures#126115
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max-charlamb merged 1 commit intodotnet:mainfrom Mar 25, 2026
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Pull request overview
Aligns cDAC ClrDataFrame behavior with the native DAC to avoid Debug.Assert parity failures when analyzing older runtime dumps (e.g., 10.0.5), particularly around locals/argument signature handling.
Changes:
GetNumArguments: relax DEBUG parity validation to allow cDAC success when native DAC can fail due toMetaSigpointer-traversal differences.GetLocalVariableCount: returnE_FAIL(via exception->HRESULT) when no local signature is available, matching native DAC behavior.
…gnatures The native DAC's GetLocalSig returns E_FAIL when a method has no local signature (dynamic methods, IL stubs, methods with no declared locals). The cDAC was returning S_OK with count 0 instead. This mismatch caused Debug.Assert validation failures when running against older runtimes where the cDAC succeeds but the legacy DAC returns E_FAIL. Now GetLocalVariableCount throws Marshal.GetExceptionForHR(E_FAIL) when GetLocalSignatureReader returns null, matching the native DAC behavior. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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/ba-g cDAC only change |
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Changes
GetLocalVariableCount — return E_FAIL for missing local signatures
The native DAC's
GetLocalSigreturnsE_FAILwhen a method has no local signature (dynamic methods, IL stubs, methods with no declared locals). The cDAC was returningS_OKwith count 0 instead. This mismatch caused validation asserts to fire.Now
GetLocalVariableCountthrowsMarshal.GetExceptionForHR(E_FAIL)whenGetLocalSignatureReaderreturns null, matching the native DAC behavior exactly.Testing
GetNumLocalVariablesreturnsE_FAILfor methods without locals (DAC parity)