Remove calli target tagging from CoreCLR interop stubs by Copilot · Pull Request #131642 · dotnet/runtime

Copilot · 2026-07-31T12:56:36Z

This change removes the (target << 1) | 1 encoding previously used for marshaling-required unmanaged calli paths. MethodDesc and unmanaged target handling now follow their actual storage semantics instead of relying on low-bit tagging.

Interop stub fast paths
- Removes target tagging from GenericPInvokeCalliHelper on 64-bit architectures.
- Removes the matching decode path in PInvokeStubLinker::DoPInvoke.
- Deletes stale debugger/interop cleanup that still assumed tagged calli targets.
InlinedCallFrame semantics
- Simplifies InlinedCallFrame::HasFunction for non-32-bit targets to treat non-null m_Datum as a function-bearing frame.
- Preserves the existing 32-bit stack-size sentinel behavior where m_Datum is still overloaded for indirect-call stack metadata.
- Updates comments to describe the remaining contract precisely.
EH marker cleanup
- Normalizes InlinedCallFrameMarker::ExceptionHandlingHelper handling to a single low-bit marker.
- Removes 64-bit-specific assumptions that only existed because of calli target tagging.
cDAC stack walking
- Updates cDAC StackWalk frame interpretation to match the new runtime encoding rules.
- Adjusts unit tests that validate EH-helper detection and InlinedCallFrame classification.

Example of the removed special-case flow:

// old
target = (target << 1) | 1;
...
EmitLoadStubContext(pcsEmit, dwStubFlags);
pcsEmit->EmitLDC(1);
pcsEmit->EmitSHR_UN();

// new
EmitLoadStubContext(pcsEmit, dwStubFlags);

Note

This PR description was created by GitHub Copilot.

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

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azure-pipelines · 2026-07-31T12:57:36Z

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dotnet-policy-service · 2026-07-31T13:24:57Z

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jkotas · 2026-07-31T19:10:10Z

@copilot Change this to be x86 specific

Addressed in 8b5a9ce.

jkotas · 2026-07-31T19:12:42Z

-        // If the stub parameter value is not needed, m_Datum will be initialized by the VM.
+        // CALLI stubs use the secret stub argument directly as the unmanaged target, so they leave m_Datum
+        // unused and keep the target only in the secret stub argument slot.
        if (m_compiler->info.compPublishStubParam)


@copilot Just set the datum field to 0 here. Instead modify the IL generated for ILStubs to set the datum field to MethodDesc explicitly in the shared IL stubs that need it.

Fixed in 0e77207.

jkotas · 2026-07-31T19:16:00Z

@copilot Delete this method and inline the logic into GetFunction_Impl - the only place where this method is called

Fixed in 0e77207.

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jkotas · 2026-08-02T03:21:57Z

            return true;
        }

+        case NI_System_StubHelpers_SetNextCallFrameMethodDesc:


@copilot Revert all changes related to SetNextCallFrameMethodDesc

Reverted all SetNextCallFrameMethodDesc-related changes in 963f13c.

jkotas · 2026-08-02T03:23:12Z

+        if (m_compiler->info.compPublishStubParam && call->HasInlinedCallFrameMethodDesc())
+        {
+            src = m_compiler->gtNewLclvNode(call->GetInlinedCallFrameMethodDescLclNum(), TYP_I_IMPL);
+        }
+        else if (m_compiler->opts.jitFlags->IsSet(JitFlags::JIT_FLAG_PUBLISH_STUB_PARAM_ICF_MD))


Suggested change

if (m_compiler->info.compPublishStubParam && call->HasInlinedCallFrameMethodDesc())

{

src = m_compiler->gtNewLclvNode(call->GetInlinedCallFrameMethodDescLclNum(), TYP_I_IMPL);

}

else if (m_compiler->opts.jitFlags->IsSet(JitFlags::JIT_FLAG_PUBLISH_STUB_PARAM_ICF_MD))

if (m_compiler->opts.jitFlags->IsSet(JitFlags::JIT_FLAG_PUBLISH_STUB_PARAM_ICF_MD))

Fixed in 963f13c.

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jkotas · 2026-08-02T04:18:03Z

        CORJIT_FLAG_SOFTFP_ABI              = 30, // Enable armel calling convention
 #endif
        CORJIT_FLAG_USE_DISPATCH_HELPERS    = 31, // The JIT should use helpers for interface dispatch instead of virtual stub dispatch
+        CORJIT_FLAG_PUBLISH_STUB_PARAM_ICF_MD = 32, // JIT should publish the stub secret param in InlinedCallFrame.m_Datum for indirect unmanaged calls


@copilot Delete this flag. We do not need to set the datum field for shared stubs

jkotas · 2026-08-02T04:18:19Z

-    0xe1ec,
-    0x4f52,
-    {0xa1, 0xbf, 0xf9, 0x19, 0x90, 0x8a, 0xa3, 0x3c}
+constexpr GUID JITEEVersionIdentifier = { /* 8445fef6-8ba2-4cd4-bf1a-fa0c0fc276de */


@copilot Revert changes in this file

Copilot AI and others added 3 commits July 31, 2026 12:34

Remove calli target tagging

625ef5b

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Progress calli validation

f43a7d6

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Address cdac and 32-bit follow-ups

d657dd8

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

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github-actions Bot added the area-VM-coreclr label Jul 31, 2026

Address PR feedback on x86-specific ICF handling

6d74dac

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Make indirect calli m_Datum handling x86-specific

8b5a9ce

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Copilot AI review requested due to automatic review settings July 31, 2026 19:31

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Comment thread src/coreclr/jit/importercalls.cpp

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Comment thread src/coreclr/jit/lower.cpp Outdated

Revert importercalls.cpp changes per review

a59394d

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Copilot AI review requested due to automatic review settings August 1, 2026 11:53

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Restore lower.cpp MethodDesc publication path

bddb704

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Copilot AI review requested due to automatic review settings August 1, 2026 11:58

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Move ICF fallback assignment into else branch

9de837f

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Copilot AI review requested due to automatic review settings August 1, 2026 12:21

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Revert SetNextCallFrameMethodDesc changes

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Copilot AI commented Jul 31, 2026 •

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