[clr-interp] Fix Swift error handling for marshaled P/Invokes in interpreter

[kotlarmilos]

Description

When a Swift P/Invoke requires marshaling (e.g. ref SwiftError), the interpreter creates an IL stub with a calli to the native function. Previously, the P/Invoke MethodDesc had no interpreter code, so INTOP_CALL fell through to InvokeManagedMethod, creating an outer native transition via InterpreterStub. The inner calli created a second transition. The inner Load_SwiftError captured x21 correctly, but ExecuteInterpretedMethod could save/restore x21 as a callee-saved register, causing the outer epilog to read a stale value.

Debug actually also had two native transitions but it just passed by coincidence because the unoptimized C compiler didn't use x21 as a scratch register, so the SwiftError value survived through ExecuteInterpretedMethod.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/wasm/helpers.cpp:732

• pContextMD is unused in the WASM implementation of GetCookieForCalliSig, which can trigger -Wunused-parameter//WX build breaks. Either remove the parameter name (keep the type for signature compatibility) or explicitly mark it unused (e.g., UNREFERENCED_PARAMETER(pContextMD)).

void* GetCookieForCalliSig(MetaSig metaSig, MethodDesc *pContextMD)
{
STANDARD_VM_CONTRACT;
void* thunk = ComputeCalliSigThunk(metaSig);
if (thunk == NULL)
{
PORTABILITY_ASSERT("GetCookieForCalliSig: unknown thunk signature");

---

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[janvorli]

LGTM, thank you!

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

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[kotlarmilos]

Description

When a Swift P/Invoke requires marshaling (e.g. ref SwiftError), the interpreter creates an IL stub with a calli to the native function. Previously, the P/Invoke MethodDesc had no interpreter code, so INTOP_CALL fell through to InvokeManagedMethod, creating an outer native transition via InterpreterStub. The inner calli created a second transition. The inner Load_SwiftError captured x21 correctly, but ExecuteInterpretedMethod could save/restore x21 as a callee-saved register, causing the outer epilog to read a stale value.

Debug actually also had two native transitions but it just passed by coincidence because the unoptimized C compiler didn't use x21 as a scratch register, so the SwiftError value survived through ExecuteInterpretedMethod.

[dotnet-policy-service]

Tagging subscribers to this area: @BrzVlad, @janvorli, @kg
See info in area-owners.md if you want to be subscribed.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/wasm/helpers.cpp:732

• pContextMD is unused in the WASM implementation of GetCookieForCalliSig, which can trigger -Wunused-parameter//WX build breaks. Either remove the parameter name (keep the type for signature compatibility) or explicitly mark it unused (e.g., UNREFERENCED_PARAMETER(pContextMD)).

void* GetCookieForCalliSig(MetaSig metaSig, MethodDesc *pContextMD)
{
STANDARD_VM_CONTRACT;
void* thunk = ComputeCalliSigThunk(metaSig);
if (thunk == NULL)
{
PORTABILITY_ASSERT("GetCookieForCalliSig: unknown thunk signature");

---

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[janvorli]

LGTM, thank you!

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

You can also share your feedback on Copilot code review. Take the survey.

[kotlarmilos]

Description

When a Swift P/Invoke requires marshaling (e.g. ref SwiftError), the interpreter creates an IL stub with a calli to the native function. Previously, the P/Invoke MethodDesc had no interpreter code, so INTOP_CALL fell through to InvokeManagedMethod, creating an outer native transition via InterpreterStub. The inner calli created a second transition. The inner Load_SwiftError captured x21 correctly, but ExecuteInterpretedMethod could save/restore x21 as a callee-saved register, causing the outer epilog to read a stale value.

Debug actually also had two native transitions but it just passed by coincidence because the unoptimized C compiler didn't use x21 as a scratch register, so the SwiftError value survived through ExecuteInterpretedMethod.

[dotnet-policy-service]

Tagging subscribers to this area: @BrzVlad, @janvorli, @kg
See info in area-owners.md if you want to be subscribed.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/wasm/helpers.cpp:732

• pContextMD is unused in the WASM implementation of GetCookieForCalliSig, which can trigger -Wunused-parameter//WX build breaks. Either remove the parameter name (keep the type for signature compatibility) or explicitly mark it unused (e.g., UNREFERENCED_PARAMETER(pContextMD)).

void* GetCookieForCalliSig(MetaSig metaSig, MethodDesc *pContextMD)
{
STANDARD_VM_CONTRACT;
void* thunk = ComputeCalliSigThunk(metaSig);
if (thunk == NULL)
{
PORTABILITY_ASSERT("GetCookieForCalliSig: unknown thunk signature");

---

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[janvorli]

LGTM, thank you!

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

You can also share your feedback on Copilot code review. Take the survey.

[kotlarmilos]

Description

When a Swift P/Invoke requires marshaling (e.g. ref SwiftError), the interpreter creates an IL stub with a calli to the native function. Previously, the P/Invoke MethodDesc had no interpreter code, so INTOP_CALL fell through to InvokeManagedMethod, creating an outer native transition via InterpreterStub. The inner calli created a second transition. The inner Load_SwiftError captured x21 correctly, but ExecuteInterpretedMethod could save/restore x21 as a callee-saved register, causing the outer epilog to read a stale value.

Debug actually also had two native transitions but it just passed by coincidence because the unoptimized C compiler didn't use x21 as a scratch register, so the SwiftError value survived through ExecuteInterpretedMethod.

[dotnet-policy-service]

Tagging subscribers to this area: @BrzVlad, @janvorli, @kg
See info in area-owners.md if you want to be subscribed.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/wasm/helpers.cpp:732

• pContextMD is unused in the WASM implementation of GetCookieForCalliSig, which can trigger -Wunused-parameter//WX build breaks. Either remove the parameter name (keep the type for signature compatibility) or explicitly mark it unused (e.g., UNREFERENCED_PARAMETER(pContextMD)).

void* GetCookieForCalliSig(MetaSig metaSig, MethodDesc *pContextMD)
{
STANDARD_VM_CONTRACT;
void* thunk = ComputeCalliSigThunk(metaSig);
if (thunk == NULL)
{
PORTABILITY_ASSERT("GetCookieForCalliSig: unknown thunk signature");

---

You can also share your feedback on Copilot code review. Take the survey.

[janvorli]

LGTM, thank you!

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

You can also share your feedback on Copilot code review. Take the survey.

[kotlarmilos]

Description

When a Swift P/Invoke requires marshaling (e.g. ref SwiftError), the interpreter creates an IL stub with a calli to the native function. Previously, the P/Invoke MethodDesc had no interpreter code, so INTOP_CALL fell through to InvokeManagedMethod, creating an outer native transition via InterpreterStub. The inner calli created a second transition. The inner Load_SwiftError captured x21 correctly, but ExecuteInterpretedMethod could save/restore x21 as a callee-saved register, causing the outer epilog to read a stale value.

Debug actually also had two native transitions but it just passed by coincidence because the unoptimized C compiler didn't use x21 as a scratch register, so the SwiftError value survived through ExecuteInterpretedMethod.

[dotnet-policy-service]

Tagging subscribers to this area: @BrzVlad, @janvorli, @kg
See info in area-owners.md if you want to be subscribed.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/wasm/helpers.cpp:732

• pContextMD is unused in the WASM implementation of GetCookieForCalliSig, which can trigger -Wunused-parameter//WX build breaks. Either remove the parameter name (keep the type for signature compatibility) or explicitly mark it unused (e.g., UNREFERENCED_PARAMETER(pContextMD)).

void* GetCookieForCalliSig(MetaSig metaSig, MethodDesc *pContextMD)
{
STANDARD_VM_CONTRACT;
void* thunk = ComputeCalliSigThunk(metaSig);
if (thunk == NULL)
{
PORTABILITY_ASSERT("GetCookieForCalliSig: unknown thunk signature");

---

You can also share your feedback on Copilot code review. Take the survey.

[janvorli]

LGTM, thank you!

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

You can also share your feedback on Copilot code review. Take the survey.

[kotlarmilos]

Description

When a Swift P/Invoke requires marshaling (e.g. ref SwiftError), the interpreter creates an IL stub with a calli to the native function. Previously, the P/Invoke MethodDesc had no interpreter code, so INTOP_CALL fell through to InvokeManagedMethod, creating an outer native transition via InterpreterStub. The inner calli created a second transition. The inner Load_SwiftError captured x21 correctly, but ExecuteInterpretedMethod could save/restore x21 as a callee-saved register, causing the outer epilog to read a stale value.

Debug actually also had two native transitions but it just passed by coincidence because the unoptimized C compiler didn't use x21 as a scratch register, so the SwiftError value survived through ExecuteInterpretedMethod.

[dotnet-policy-service]

Tagging subscribers to this area: @BrzVlad, @janvorli, @kg
See info in area-owners.md if you want to be subscribed.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/wasm/helpers.cpp:732

• pContextMD is unused in the WASM implementation of GetCookieForCalliSig, which can trigger -Wunused-parameter//WX build breaks. Either remove the parameter name (keep the type for signature compatibility) or explicitly mark it unused (e.g., UNREFERENCED_PARAMETER(pContextMD)).

void* GetCookieForCalliSig(MetaSig metaSig, MethodDesc *pContextMD)
{
STANDARD_VM_CONTRACT;
void* thunk = ComputeCalliSigThunk(metaSig);
if (thunk == NULL)
{
PORTABILITY_ASSERT("GetCookieForCalliSig: unknown thunk signature");

---

You can also share your feedback on Copilot code review. Take the survey.

[janvorli]

LGTM, thank you!

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

You can also share your feedback on Copilot code review. Take the survey.

[kotlarmilos]

Description

When a Swift P/Invoke requires marshaling (e.g. ref SwiftError), the interpreter creates an IL stub with a calli to the native function. Previously, the P/Invoke MethodDesc had no interpreter code, so INTOP_CALL fell through to InvokeManagedMethod, creating an outer native transition via InterpreterStub. The inner calli created a second transition. The inner Load_SwiftError captured x21 correctly, but ExecuteInterpretedMethod could save/restore x21 as a callee-saved register, causing the outer epilog to read a stale value.

Debug actually also had two native transitions but it just passed by coincidence because the unoptimized C compiler didn't use x21 as a scratch register, so the SwiftError value survived through ExecuteInterpretedMethod.

[dotnet-policy-service]

Tagging subscribers to this area: @BrzVlad, @janvorli, @kg
See info in area-owners.md if you want to be subscribed.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/wasm/helpers.cpp:732

• pContextMD is unused in the WASM implementation of GetCookieForCalliSig, which can trigger -Wunused-parameter//WX build breaks. Either remove the parameter name (keep the type for signature compatibility) or explicitly mark it unused (e.g., UNREFERENCED_PARAMETER(pContextMD)).

void* GetCookieForCalliSig(MetaSig metaSig, MethodDesc *pContextMD)
{
STANDARD_VM_CONTRACT;
void* thunk = ComputeCalliSigThunk(metaSig);
if (thunk == NULL)
{
PORTABILITY_ASSERT("GetCookieForCalliSig: unknown thunk signature");

---

You can also share your feedback on Copilot code review. Take the survey.

[janvorli]

LGTM, thank you!

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

You can also share your feedback on Copilot code review. Take the survey.

[kotlarmilos]

Description

When a Swift P/Invoke requires marshaling (e.g. ref SwiftError), the interpreter creates an IL stub with a calli to the native function. Previously, the P/Invoke MethodDesc had no interpreter code, so INTOP_CALL fell through to InvokeManagedMethod, creating an outer native transition via InterpreterStub. The inner calli created a second transition. The inner Load_SwiftError captured x21 correctly, but ExecuteInterpretedMethod could save/restore x21 as a callee-saved register, causing the outer epilog to read a stale value.

Debug actually also had two native transitions but it just passed by coincidence because the unoptimized C compiler didn't use x21 as a scratch register, so the SwiftError value survived through ExecuteInterpretedMethod.

[dotnet-policy-service]

Tagging subscribers to this area: @BrzVlad, @janvorli, @kg
See info in area-owners.md if you want to be subscribed.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/wasm/helpers.cpp:732

• pContextMD is unused in the WASM implementation of GetCookieForCalliSig, which can trigger -Wunused-parameter//WX build breaks. Either remove the parameter name (keep the type for signature compatibility) or explicitly mark it unused (e.g., UNREFERENCED_PARAMETER(pContextMD)).

void* GetCookieForCalliSig(MetaSig metaSig, MethodDesc *pContextMD)
{
STANDARD_VM_CONTRACT;
void* thunk = ComputeCalliSigThunk(metaSig);
if (thunk == NULL)
{
PORTABILITY_ASSERT("GetCookieForCalliSig: unknown thunk signature");

---

You can also share your feedback on Copilot code review. Take the survey.

[janvorli]

LGTM, thank you!

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

You can also share your feedback on Copilot code review. Take the survey.