[clr-interp] Report async-suspension locals to the debugger via GetAsyncLocals by kotlarmilos · Pull Request #127757 · dotnet/runtime

kotlarmilos · 2026-05-04T14:54:42Z

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

Async.AsyncSimple
Async.AsyncBreakpoint
Async.AsyncBreakpointJmc
Async.AsyncGeneric
Async.AsyncRecursive
Async.AsyncSharedGeneric
Async.AsyncV2CallingAsyncV1Iterator
Async.AsyncGenericStepInto

Copilot

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware `GetAsyncLocals` decoding to return async locals for interpreted frames.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 3

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 0 new

noahfalk

Looks good to me modulo maybe special variables are missing from the encoding.

…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bug info In InterpCompiler::EmitSuspend, the AsyncContinuationVarInfo emission was guarded by var < m_numILVars, which excluded the hidden generics-context arg stored at m_paramArgIndex. Shared-generic async methods would therefore miss the type context and the debugger could fail to resolve generic types in suspended frames. Match the JIT's compMap2ILvarNum behavior by emitting an entry for the param arg with VarNumber = ICorDebugInfo::TYPECTXT_ILNUM when m_methodInfo->args.hasTypeArg(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 2

…ying on emission order EmitCode reorders BBs in waves by overlappingEHClauseCount, so the order INTOP_HANDLE_CONTINUATION_SUSPEND opcodes are emitted does not match the order EmitSuspend assigned suspensionPointIndex. The previous code appended to m_suspensionPointIPOffsets via Add() in emission order, which produced a mismatched index->IP table whenever a method had two awaits at different EH wave depths. In checked builds the assert caught it; in release the runtime would resume at the wrong bytecode offset. Pre-size the table in EmitCode and write entries by suspensionPointIndex. Add an explicit size assert in FinalizeMethodData. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

kotlarmilos · 2026-05-04T14:54:42Z

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

Async.AsyncSimple
Async.AsyncBreakpoint
Async.AsyncBreakpointJmc
Async.AsyncGeneric
Async.AsyncRecursive
Async.AsyncSharedGeneric
Async.AsyncV2CallingAsyncV1Iterator
Async.AsyncGenericStepInto

Copilot

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware `GetAsyncLocals` decoding to return async locals for interpreted frames.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 3

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 0 new

noahfalk

Looks good to me modulo maybe special variables are missing from the encoding.

…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bug info In InterpCompiler::EmitSuspend, the AsyncContinuationVarInfo emission was guarded by var < m_numILVars, which excluded the hidden generics-context arg stored at m_paramArgIndex. Shared-generic async methods would therefore miss the type context and the debugger could fail to resolve generic types in suspended frames. Match the JIT's compMap2ILvarNum behavior by emitting an entry for the param arg with VarNumber = ICorDebugInfo::TYPECTXT_ILNUM when m_methodInfo->args.hasTypeArg(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 2

…ying on emission order EmitCode reorders BBs in waves by overlappingEHClauseCount, so the order INTOP_HANDLE_CONTINUATION_SUSPEND opcodes are emitted does not match the order EmitSuspend assigned suspensionPointIndex. The previous code appended to m_suspensionPointIPOffsets via Add() in emission order, which produced a mismatched index->IP table whenever a method had two awaits at different EH wave depths. In checked builds the assert caught it; in release the runtime would resume at the wrong bytecode offset. Pre-size the table in EmitCode and write entries by suspensionPointIndex. Add an explicit size assert in FinalizeMethodData. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

kotlarmilos · 2026-05-04T14:54:42Z

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

Async.AsyncSimple
Async.AsyncBreakpoint
Async.AsyncBreakpointJmc
Async.AsyncGeneric
Async.AsyncRecursive
Async.AsyncSharedGeneric
Async.AsyncV2CallingAsyncV1Iterator
Async.AsyncGenericStepInto

Copilot

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware `GetAsyncLocals` decoding to return async locals for interpreted frames.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 3

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 0 new

noahfalk

Looks good to me modulo maybe special variables are missing from the encoding.

…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bug info In InterpCompiler::EmitSuspend, the AsyncContinuationVarInfo emission was guarded by var < m_numILVars, which excluded the hidden generics-context arg stored at m_paramArgIndex. Shared-generic async methods would therefore miss the type context and the debugger could fail to resolve generic types in suspended frames. Match the JIT's compMap2ILvarNum behavior by emitting an entry for the param arg with VarNumber = ICorDebugInfo::TYPECTXT_ILNUM when m_methodInfo->args.hasTypeArg(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 2

…ying on emission order EmitCode reorders BBs in waves by overlappingEHClauseCount, so the order INTOP_HANDLE_CONTINUATION_SUSPEND opcodes are emitted does not match the order EmitSuspend assigned suspensionPointIndex. The previous code appended to m_suspensionPointIPOffsets via Add() in emission order, which produced a mismatched index->IP table whenever a method had two awaits at different EH wave depths. In checked builds the assert caught it; in release the runtime would resume at the wrong bytecode offset. Pre-size the table in EmitCode and write entries by suspensionPointIndex. Add an explicit size assert in FinalizeMethodData. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

kotlarmilos · 2026-05-04T14:54:42Z

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

Async.AsyncSimple
Async.AsyncBreakpoint
Async.AsyncBreakpointJmc
Async.AsyncGeneric
Async.AsyncRecursive
Async.AsyncSharedGeneric
Async.AsyncV2CallingAsyncV1Iterator
Async.AsyncGenericStepInto

Copilot

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware `GetAsyncLocals` decoding to return async locals for interpreted frames.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 3

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 0 new

noahfalk

Looks good to me modulo maybe special variables are missing from the encoding.

…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bug info In InterpCompiler::EmitSuspend, the AsyncContinuationVarInfo emission was guarded by var < m_numILVars, which excluded the hidden generics-context arg stored at m_paramArgIndex. Shared-generic async methods would therefore miss the type context and the debugger could fail to resolve generic types in suspended frames. Match the JIT's compMap2ILvarNum behavior by emitting an entry for the param arg with VarNumber = ICorDebugInfo::TYPECTXT_ILNUM when m_methodInfo->args.hasTypeArg(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 2

…ying on emission order EmitCode reorders BBs in waves by overlappingEHClauseCount, so the order INTOP_HANDLE_CONTINUATION_SUSPEND opcodes are emitted does not match the order EmitSuspend assigned suspensionPointIndex. The previous code appended to m_suspensionPointIPOffsets via Add() in emission order, which produced a mismatched index->IP table whenever a method had two awaits at different EH wave depths. In checked builds the assert caught it; in release the runtime would resume at the wrong bytecode offset. Pre-size the table in EmitCode and write entries by suspensionPointIndex. Add an explicit size assert in FinalizeMethodData. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

kotlarmilos · 2026-05-04T14:54:42Z

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

Async.AsyncSimple
Async.AsyncBreakpoint
Async.AsyncBreakpointJmc
Async.AsyncGeneric
Async.AsyncRecursive
Async.AsyncSharedGeneric
Async.AsyncV2CallingAsyncV1Iterator
Async.AsyncGenericStepInto

Copilot

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware `GetAsyncLocals` decoding to return async locals for interpreted frames.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 3

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 0 new

noahfalk

Looks good to me modulo maybe special variables are missing from the encoding.

…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bug info In InterpCompiler::EmitSuspend, the AsyncContinuationVarInfo emission was guarded by var < m_numILVars, which excluded the hidden generics-context arg stored at m_paramArgIndex. Shared-generic async methods would therefore miss the type context and the debugger could fail to resolve generic types in suspended frames. Match the JIT's compMap2ILvarNum behavior by emitting an entry for the param arg with VarNumber = ICorDebugInfo::TYPECTXT_ILNUM when m_methodInfo->args.hasTypeArg(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 2

…ying on emission order EmitCode reorders BBs in waves by overlappingEHClauseCount, so the order INTOP_HANDLE_CONTINUATION_SUSPEND opcodes are emitted does not match the order EmitSuspend assigned suspensionPointIndex. The previous code appended to m_suspensionPointIPOffsets via Add() in emission order, which produced a mismatched index->IP table whenever a method had two awaits at different EH wave depths. In checked builds the assert caught it; in release the runtime would resume at the wrong bytecode offset. Pre-size the table in EmitCode and write entries by suspensionPointIndex. Add an explicit size assert in FinalizeMethodData. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

kotlarmilos · 2026-05-04T14:54:42Z

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

Async.AsyncSimple
Async.AsyncBreakpoint
Async.AsyncBreakpointJmc
Async.AsyncGeneric
Async.AsyncRecursive
Async.AsyncSharedGeneric
Async.AsyncV2CallingAsyncV1Iterator
Async.AsyncGenericStepInto

Copilot

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware `GetAsyncLocals` decoding to return async locals for interpreted frames.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 3

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 0 new

noahfalk

Looks good to me modulo maybe special variables are missing from the encoding.

…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bug info In InterpCompiler::EmitSuspend, the AsyncContinuationVarInfo emission was guarded by var < m_numILVars, which excluded the hidden generics-context arg stored at m_paramArgIndex. Shared-generic async methods would therefore miss the type context and the debugger could fail to resolve generic types in suspended frames. Match the JIT's compMap2ILvarNum behavior by emitting an entry for the param arg with VarNumber = ICorDebugInfo::TYPECTXT_ILNUM when m_methodInfo->args.hasTypeArg(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 2

…ying on emission order EmitCode reorders BBs in waves by overlappingEHClauseCount, so the order INTOP_HANDLE_CONTINUATION_SUSPEND opcodes are emitted does not match the order EmitSuspend assigned suspensionPointIndex. The previous code appended to m_suspensionPointIPOffsets via Add() in emission order, which produced a mismatched index->IP table whenever a method had two awaits at different EH wave depths. In checked builds the assert caught it; in release the runtime would resume at the wrong bytecode offset. Pre-size the table in EmitCode and write entries by suspensionPointIndex. Add an explicit size assert in FinalizeMethodData. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

kotlarmilos · 2026-05-04T14:54:42Z

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

Async.AsyncSimple
Async.AsyncBreakpoint
Async.AsyncBreakpointJmc
Async.AsyncGeneric
Async.AsyncRecursive
Async.AsyncSharedGeneric
Async.AsyncV2CallingAsyncV1Iterator
Async.AsyncGenericStepInto

Copilot

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware `GetAsyncLocals` decoding to return async locals for interpreted frames.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 3

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 1

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 0 new

noahfalk

Looks good to me modulo maybe special variables are missing from the encoding.

…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bug info In InterpCompiler::EmitSuspend, the AsyncContinuationVarInfo emission was guarded by var < m_numILVars, which excluded the hidden generics-context arg stored at m_paramArgIndex. Shared-generic async methods would therefore miss the type context and the debugger could fail to resolve generic types in suspended frames. Match the JIT's compMap2ILvarNum behavior by emitting an entry for the param arg with VarNumber = ICorDebugInfo::TYPECTXT_ILNUM when m_methodInfo->args.hasTypeArg(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

Files reviewed: 4/4 changed files
Comments generated: 2

…ying on emission order EmitCode reorders BBs in waves by overlappingEHClauseCount, so the order INTOP_HANDLE_CONTINUATION_SUSPEND opcodes are emitted does not match the order EmitSuspend assigned suspensionPointIndex. The previous code appended to m_suspensionPointIPOffsets via Add() in emission order, which produced a mismatched index->IP table whenever a method had two awaits at different EH wave depths. In checked builds the assert caught it; in release the runtime would resume at the wrong bytecode offset. Pre-size the table in EmitCode and write entries by suspensionPointIndex. Add an explicit size assert in FinalizeMethodData. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

kotlarmilos · 2026-05-04T14:54:42Z

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

Async.AsyncSimple
Async.AsyncBreakpoint
Async.AsyncBreakpointJmc
Async.AsyncGeneric
Async.AsyncRecursive
Async.AsyncSharedGeneric
Async.AsyncV2CallingAsyncV1Iterator
Async.AsyncGenericStepInto

Copilot

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware `GetAsyncLocals` decoding to return async locals for interpreted frames.

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 3

Copilot

Copilot's findings

Files reviewed: 3/3 changed files
Comments generated: 1

Copilot

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noahfalk

Looks good to me modulo maybe special variables are missing from the encoding.

…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…bug info In InterpCompiler::EmitSuspend, the AsyncContinuationVarInfo emission was guarded by var < m_numILVars, which excluded the hidden generics-context arg stored at m_paramArgIndex. Shared-generic async methods would therefore miss the type context and the debugger could fail to resolve generic types in suspended frames. Match the JIT's compMap2ILvarNum behavior by emitting an entry for the param arg with VarNumber = ICorDebugInfo::TYPECTXT_ILNUM when m_methodInfo->args.hasTypeArg(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Copilot's findings

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Comments generated: 2

…ying on emission order EmitCode reorders BBs in waves by overlappingEHClauseCount, so the order INTOP_HANDLE_CONTINUATION_SUSPEND opcodes are emitted does not match the order EmitSuspend assigned suspensionPointIndex. The previous code appended to m_suspensionPointIPOffsets via Add() in emission order, which produced a mismatched index->IP table whenever a method had two awaits at different EH wave depths. In checked builds the assert caught it; in release the runtime would resume at the wrong bytecode offset. Pre-size the table in EmitCode and write entries by suspensionPointIndex. Add an explicit size assert in FinalizeMethodData. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

CopilotAI review requested due to automatic review settings May 4, 2026 14:54

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github-actionsBot added the area-CodeGen-Interpreter-coreclr label May 4, 2026

kotlarmilos marked this pull request as draft May 4, 2026 14:55

kotlarmilos changed the title ~~[interp] Report async-suspension locals to the debugger via GetAsyncLocals~~[interp] Report async locals to the debugger via GetAsyncLocalsMay 4, 2026

kotlarmilos changed the title ~~[interp] Report async locals to the debugger via GetAsyncLocals~~[clr-interp] Report async locals to the debugger via GetAsyncLocalsMay 4, 2026

kotlarmilos added this to the 11.0.0 milestone May 4, 2026

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kotlarmilos force-pushed the interp-async-debug-locals branch 3 times, most recently from 35b435b to d41eea4Compare May 4, 2026 14:59

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kotlarmilos changed the title ~~[clr-interp] Report async locals to the debugger via GetAsyncLocals~~[clr-interp] Report async-suspension locals to the debugger via GetAsyncLocalsMay 4, 2026

kotlarmilos force-pushed the interp-async-debug-locals branch from d41eea4 to c873f5aCompare May 4, 2026 15:19

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kotlarmilos force-pushed the interp-async-debug-locals branch from c873f5a to 59cef97Compare May 4, 2026 15:19

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build-analysisBot mentioned this pull request May 4, 2026
The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#3008
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slow macOS - "##[error]The job running on agent Azure Pipelines 9 ran longer than the maximum time of 60 minutes." dotnet/dnceng#1883
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This was referenced May 5, 2026
Unable to pull image from mcr.microsoft.com #117164
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XHarness package install failure on iOS due to devicectl NSPOSIXErrorDomain error 49 #123796
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This was referenced May 7, 2026
[clr-ios] Enable debugging on CoreCLR mobile platforms #124744
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[clr-interp] Implement interpreter debugging support in CoreCLR #120842
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[clr-interp] Move InterpByteCodeStart header into negative space in front of the code pointer #128081
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kotlarmilos force-pushed the interp-async-debug-locals branch from 9f75709 to 593d29bCompare May 12, 2026 14:12

kotlarmilosand others added 2 commits May 12, 2026 16:17

[interp] Report async-suspension locals to the debugger via GetAsyncL…
a4011ef
…ocals Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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kotlarmilos merged commit edcc3af into dotnet:mainMay 13, 2026
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dotnet-maestroBot mentioned this pull request May 14, 2026
[main] Source code updates from dotnet/runtime dotnet/dotnet#6573
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lewing mentioned this pull request May 22, 2026
Coreclr WASI interpreter (resurrected from #126959) #128465
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