WIP: cDAC shared calling-convention port + ByRefLike walker + Win-x64 CallSiteLayout dump tests [NO-REVIEW]#128487
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Recovered from a dangling git stash that was previously lost. Includes: - Per-arch ArgIterator port under src/native/managed/cdac/.../Contracts/CallingConvention/ (X86, AMD64-Unix, AMD64-Windows, Arm32, Arm64, RiscV64+LoongArch64) atop ArgIteratorBase / ArgIteratorData / ArgIteratorFactory / TransitionBlockLayout. - New ICallingConvention contract and CallingConvention_1 implementation that drives the iterators from a decoded signature. - New data descriptor entries for TransitionBlock + ArgumentRegisters (src/coreclr/vm/datadescriptor/datadescriptor.inc, src/coreclr/vm/class.h). - GcScanner refactored to consume CallSiteLayout for caller-stack promotion; CallingConvention contract fetched lazily so stack-walk tests that do not register it still work. - Test suite under src/native/managed/cdac/tests/CallingConvention/ covering 214 per-arch cases, plus MockDescriptors.CallingConvention support and RuntimeTypeSystemGetVectorSizeTests. Post-recovery cleanup applied on top of the original stash: - Files relocated from Contracts/StackWalk/CallingConvention/ to Contracts/CallingConvention/; helper namespace renamed to Contracts.CallingConventionHelpers (matches Contracts/GCInfo/ pattern). - Collapsed the abstract AMD64UnixArgIterator + CdacAMD64UnixArgIterator pair into a single concrete AMD64UnixArgIterator. - Dropped vestigial extraObjectFirstArg / extraFunctionPointerArg ctor parameters that were never set to true in any caller. - Fixed API drift vs. current origin/main (GenericContextLoc-based check, non-generic ArgIterator types, Target.FieldInfo.TypeName). Builds cdac.slnx clean (0 errors, 0 warnings). Test result: 2469 passed, 0 failed, 16 skipped. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Add IRuntimeTypeSystem.EnumerateInstanceFieldDescs and LookupApproxFieldTypeHandle primitives - Implement GcRefEnumeration.EnumerateByRefLikeRoots walker (recursive field scan) - Update CallingConvention_1.ComputeValueTypeHandle to populate handle for ByRefLike args - GcScanner.ReportArgument dispatches to ByRefLike walker via rts.IsByRefLike - Consolidate duplicate LookupApproxFieldTypeHandle/ResolveFieldTypeHandle helpers - Add unit tests for ByRefLike dispatch in GcScannerReportArgumentTests Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Rebuild the CallSiteLayout debuggee as a 54-frame deep chain that
exercises every interesting AMD64 calling-convention shape (categories
A-H: empty/int/double argbanks, mixed reg banks, managed ref args,
small/large value types, ByRefLike + Span<T>, instance/retbuf/generic/
vararg specials, Vector64/128/256/512, composite kitchen-sink frames).
All 54 frames stay live to Environment.FailFast so a single dump
captures the whole matrix on the FailFast thread.
Replace CallSiteLayoutDumpTests with:
- CallSiteLayoutDumpTestsBase: shared DumpTestBase subclass providing
CollectChainMethods / LayoutFor / AssertSingle{ByRef,ByValueVT,
ManagedRef} helpers.
- CallSiteLayoutDumpTests_WinX64: 46 [ConditionalTheory] tests gated
by [SkipOnOS=windows], [SkipOnArch=x64], [SkipOnVersion=net10.0]
asserting the explicit Win-x64 layout (IsPassedByRef, slot offsets,
ValueTypeHandle populated/null) for every frame.
The tests are expectation-snapshots derived from the AMD64 Windows ABI.
They pin cDAC ICallingConvention.ComputeCallSiteLayout output to the
hand-derived spec. Independent ground-truth validation via SOS
!clrstack -gc + transition frames is a tracked follow-up; the current
SOS path exercises ComputeCallSiteLayout only on InlinedCallFrames.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag |
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Superseded by #128488 (AMD64-only slim). Closing in favor of that surface. |
This was referenced May 22, 2026
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Note
This PR was prepared with assistance from GitHub Copilot.
Status: WIP / not for review (
NO-REVIEW).This branch is a long-running working branch for porting the native
ArgIteratorand calling-convention machinery into the cDAC, plusfollow-on infrastructure (ByRefLike GC ref enumeration walker,
CallSiteLayoutdump tests).The branch carries three commits today:
ArgIteratorport (X86, AMD64-Unix, AMD64-Windows, Arm32, Arm64,RiscV64 + LoongArch64) atop
ArgIteratorBase/ArgIteratorData/ArgIteratorFactory/TransitionBlockLayout. NewICallingConventioncontract +CallingConvention_1impl drivingthe iterators from a decoded signature. New data-descriptor entries
for
TransitionBlock+ArgumentRegisters.GcScannerrefactoredto consume
CallSiteLayoutfor caller-stack promotion. Unit-testsuite under
tests/CallingConvention/covering 214 per-arch cases.IRuntimeTypeSystem.EnumerateInstanceFieldDescsandLookupApproxFieldTypeHandle; implementsGcRefEnumeration.EnumerateByRefLikeRoots(recursive field scan);wires up
GcScanner.ReportArgumentto dispatch to the BRL walkervia
rts.IsByRefLike.rebuilds the
CallSiteLayoutdebuggee as a 54-frame deep chaincovering categories A-H of AMD64 calling-convention shapes, and
adds 46 Win-x64
[ConditionalTheory]tests asserting the explicitexpected layout for each frame.
Validation so far
CallSiteLayoutDumpTests_WinX64: 46/46 pass onlocaldump;net10.0 dump skipped via
[SkipOnVersion](pre-existingCodeVersionsdescriptor shape mismatch on net10.0 dumps).!clrstack -gclegacy DACvscDACdiff onCallSiteLayout.dmp: byte-identical except for one SOS header line.Confirms the GCInfo-based managed-frame stack walk matches; a
follow-up debuggee using P/Invoke bouncers is planned to extend SOS
parity coverage to
ComputeCallSiteLayoutitself (which is onlyexercised by
GcScanner.PromoteCallerStackon transition frames).CI ask
Looking to get a
CdacDumps_linux_x64.tar.gzartifact from CI so theCallSiteLayoutdebuggee can be used to author a siblingCallSiteLayoutDumpTests_SysVX64class in a follow-up commit.Not for review
This PR is marked
NO-REVIEW. Please do not invest review cycles —it exists to capture CI artifacts and as a working branch.