[wasm][coreclr] callhelpers generator, pinvoke part #123090

radekdoulik · 2026-01-12T16:54:00Z

Generate src/coreclr/vm/wasm/callhelpers-pinvoke.cpp and use it instead of hardcoded native libs entrypoints.c

Copilot

Pull request overview

This PR implements code generation for WASM/CoreCLR PInvoke tables instead of using hardcoded native library entrypoints. The generator scans managed assemblies and creates C++ files that map library names to their native function entry points.

Changes:

Modified the PInvoke table generator to split generation into separate files for PInvoke and reverse PInvoke (callbacks)
Added callhelpers-pinvoke.cpp generation that provides callhelpers_pinvoke_override function for resolving native library imports
Updated build system to conditionally compile the generated PInvoke table when GEN_PINVOKE=1
Removed libz module dependency (now covered by System.IO.Compression.Native) and added System.Native.Browser module
Modified native library build to use empty.c stub when generator is enabled

Reviewed changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/tasks/WasmAppBuilder/coreclr/PInvokeTableGenerator.cs	Refactored Generate method to create separate PInvoke and reverse PInvoke files; updated C++ output format to use minipal entrypoints; added QCall filtering
src/tasks/WasmAppBuilder/coreclr/ManagedToNativeGenerator.cs	Added ReversePInvokeOutputPath parameter to support separate reverse PInvoke generation
src/tasks/WasmAppBuilder/WasmAppBuilder.csproj	Updated module list (added System.Native.Browser, removed libz) and configured output paths for generated files
src/native/libs/System.Native.Browser/CMakeLists.txt	Added empty.c as source when GEN_PINVOKE is enabled to provide stub implementation
src/native/libs/CMakeLists.txt	Removed CORERUN_LIBS_ONLY condition for System.IO.Compression.Native to ensure it's always built
src/coreclr/vm/wasm/callhelpers-reverse.cpp	Regenerated with updated hash values for reverse thunk entries
src/coreclr/vm/wasm/callhelpers-pinvoke.cpp	New generated file containing PInvoke tables and callhelpers_pinvoke_override implementation
src/coreclr/vm/pinvokeoverride.cpp	Excluded GlobalizationResolveDllImport for WASM targets (now handled by generated code)
src/coreclr/vm/CMakeLists.txt	Conditionally includes callhelpers-pinvoke.cpp when GEN_PINVOKE is set
src/coreclr/hosts/corerun/wasm/pinvoke_override.cpp	Simplified to declare and use callhelpers_pinvoke_override from generated code
src/coreclr/hosts/corerun/CMakeLists.txt	Added System.IO.Compression.Native-Static and System.Native.Browser-Static dependencies
src/coreclr/CMakeLists.txt	Enabled GEN_PINVOKE flag for Browser/WASM builds

Comments suppressed due to low confidence (1)

src/coreclr/hosts/corerun/CMakeLists.txt:67

System.Native.Browser-Static is already linked at line 57. This duplicate link specification is redundant and should be removed to avoid unnecessary repetition.

            target_link_libraries(corerun PRIVATE
                System.Native.Browser-Static)

src/tasks/WasmAppBuilder/coreclr/PInvokeTableGenerator.cs

Co-authored-by: Copilot <[email protected]>

src/coreclr/hosts/corerun/CMakeLists.txt

src/coreclr/vm/wasm/callhelpers-pinvoke.cpp

pavelsavara · 2026-01-13T16:45:45Z

src/coreclr/vm/wasm/callhelpers-pinvoke.cpp

+    void * SystemNative_GetDefaultSearchOrderPseudoHandle ();
+    int32_t SystemNative_GetErrNo ();
+    uint32_t SystemNative_GetFileSystemType (void *);
+    int32_t SystemNative_GetIPv4Address (void *, int32_t, void *);


SystemNative_GetIPv4Address is suspect in the browser. It suggests that you generated the file with System.Net.Sockets.dll in the set. It would be good to use browser flavor of the runtime pack. Ideally with unreachable code trimmed.

AaronRobinsonMSFT · 2026-01-13T17:14:49Z

src/coreclr/hosts/corerun/wasm/pinvoke_override.cpp

 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.

 #include <string.h>


Suggested change

AaronRobinsonMSFT · 2026-01-13T17:17:18Z

src/coreclr/hosts/corerun/wasm/pinvoke_override.cpp

 #define _In_z_
 #define _In_


Suggested change

#define _In_

#include <sal.h>

Please give this a try.

AaronRobinsonMSFT · 2026-01-13T17:20:31Z

src/coreclr/vm/pinvokeoverride.cpp

+#ifdef TARGET_WASM
+    return nullptr;
+#else // !TARGET_WASM
    return DefaultResolveDllImport(libraryName, entrypointName);
+#endif // TARGET_WASM


Suggested change

#ifdef TARGET_WASM

return nullptr;

#else // !TARGET_WASM

return DefaultResolveDllImport(libraryName, entrypointName);

#endif // TARGET_WASM

return DefaultResolveDllImport(libraryName, entrypointName);

AaronRobinsonMSFT · 2026-01-13T17:20:54Z

src/coreclr/vm/pinvokeoverride.cpp

+#ifndef TARGET_WASM
 // here we handle PInvokes whose implementation is always statically linked (even in .so/.dll case)
 static const void* DefaultResolveDllImport(const char* libraryName, const char* entrypointName)
 {
    if (strcmp(libraryName, GLOBALIZATION_DLL_NAME) == 0)
    {
        return GlobalizationResolveDllImport(entrypointName);
    }

    return nullptr;
 }
+#endif // TARGET_WASM


Suggested change

// here we handle PInvokes whose implementation is always statically linked (even in .so/.dll case)

static const void* DefaultResolveDllImport(const char* libraryName, const char* entrypointName)

{

#ifndef TARGET_WASM

if (strcmp(libraryName, GLOBALIZATION_DLL_NAME) == 0)

{

return GlobalizationResolveDllImport(entrypointName);

}

#endif // TARGET_WASM

return nullptr;

}

I don't fully understand why we can't reconcile this entry point with the pinvoke_override.cpp though.

AaronRobinsonMSFT · 2026-01-13T17:23:58Z

src/native/libs/System.Native.Browser/CMakeLists.txt


-if (NOT GEN_PINVOKE)
+if (GEN_PINVOKE)
+    set (BROWSER_SOURCES ${BROWSER_SOURCES} empty.c)


Why is an empty file needed?

src/coreclr/vm/wasm/callhelpers-pinvoke.cpp

pavelsavara · 2026-01-13T19:16:04Z

src/coreclr/vm/wasm/callhelpers-reverse.cpp

-    { 2638856333, 4239234100, { &MD_System_Private_CoreLib_Internal_Runtime_InteropServices_ComActivator_RegisterClassForTypeInternal_I32_RetI32, (void*)&Call_System_Private_CoreLib_Internal_Runtime_InteropServices_ComActivator_RegisterClassForTypeInternal_I32_RetI32 } } /* alternate key source: RegisterClassForTypeInternal#1:System.Private.CoreLib:Internal.Runtime.InteropServices:ComActivator */,
-    { 2638830480, 167179540, { &MD_System_Private_CoreLib_System_Threading_TimerQueue_TimerHandler_Void_RetVoid, (void*)&Call_System_Private_CoreLib_System_Threading_TimerQueue_TimerHandler_Void_RetVoid } } /* alternate key source: TimerHandler#0:System.Private.CoreLib:System.Threading:TimerQueue */,
-    { 2638856332, 2150642223, { &MD_System_Private_CoreLib_Internal_Runtime_InteropServices_ComActivator_UnregisterClassForTypeInternal_I32_RetI32, (void*)&Call_System_Private_CoreLib_Internal_Runtime_InteropServices_ComActivator_UnregisterClassForTypeInternal_I32_RetI32 } } /* alternate key source: UnregisterClassForTypeInternal#1:System.Private.CoreLib:Internal.Runtime.InteropServices:ComActivator */
+    { 2644319180, 3863938719, { &MD_System_Private_CoreLib_System_GC__RegisterNoGCRegionCallback_g__Callback_7C_72_0_I32_RetVoid, (void*)&Call_System_Private_CoreLib_System_GC__RegisterNoGCRegionCallback_g__Callback_7C_72_0_I32_RetVoid } } /* alternate key source: <RegisterNoGCRegionCallback>g__Callback|72_0#1:System.Private.CoreLib:System:GC */,


What caused this hash to change ?

[wasm][coreclr] callhelpers generator, pinvoke part

533e0fc

Generate src/coreclr/vm/wasm/callhelpers-pinvoke.cpp and use it instead of hardcoded native libs entrypoints.c

radekdoulik added this to the Future milestone Jan 12, 2026

Copilot AI review requested due to automatic review settings January 12, 2026 16:54

radekdoulik added the area-VM-coreclr label Jan 12, 2026

radekdoulik requested review from akoeplinger and maraf as code owners January 12, 2026 16:54

dotnet-policy-service bot assigned radekdoulik Jan 12, 2026

Copilot started reviewing on behalf of radekdoulik January 12, 2026 16:54 View session

radekdoulik requested review from AaronRobinsonMSFT, jkotas and kg January 12, 2026 16:56

radekdoulik added 2 commits January 12, 2026 17:59

Style

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Remove DefaultResolveDllImport

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radekdoulik and others added 4 commits January 12, 2026 18:06

Remove old comment

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Co-authored-by: Copilot <[email protected]>

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radekdoulik mentioned this pull request Jan 13, 2026

[wasm][coreclr] pinvoke and internal calls generator #113692

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Merge branch 'main' into clr-wasm-generator-3rd

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pavelsavara reviewed Jan 13, 2026

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pavelsavara added the arch-wasm WebAssembly architecture label Jan 13, 2026

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build-analysis bot mentioned this pull request Jan 13, 2026

Cannot find 'arm64-v8a' device dotnet/dnceng#2284

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AaronRobinsonMSFT reviewed Jan 13, 2026

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pavelsavara reviewed Jan 13, 2026

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[wasm][coreclr] callhelpers generator, pinvoke part #123090

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[wasm][coreclr] callhelpers generator, pinvoke part #123090

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