[Wasm RyuJIT] Block stores by kg · Pull Request #123738 · dotnet/runtime

kg · 2026-01-28T23:35:40Z

This is sufficient to compile these three managed methods to wasm functions with native memory.fill and memory.copy instructions:

    struct S {
        public int A, B, C, D;
    }

    struct S2 {
        public string A, B, C, D;
    }

    [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
    static unsafe void zeroStruct (S *result) {
        *result = default;
    }

    [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
    static unsafe void copyStruct (S *a, S *b) {
        *a = *b;
    }

    [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
    static void zeroStructWithRefs (ref S2 result) {
        result = default;
    }

dotnet-policy-service · 2026-01-28T23:36:29Z

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kg · 2026-01-28T23:51:31Z

Not sure what i'm doing wrong here yet.


*************** Starting PHASE Lowering nodeinfo
compEnregLocals() is false, setting doNotEnreg flag for all locals.
Local V00 should not be enregistered because: opts.compFlags & CLFLG_REGVAR is not set

Local V01 should not be enregistered because: opts.compFlags & CLFLG_REGVAR is not set

Local V02 should not be enregistered because: opts.compFlags & CLFLG_REGVAR is not set

Local V03 should not be enregistered because: opts.compFlags & CLFLG_REGVAR is not set
BB02: already in WASM value stack order
lowering store lcl var/field (before):
N001 (???,???) [000002] -----+-----                    t2 =    CNS_INT   int    0
                                                            /--*  t2     int    
N002 (???,???) [000003] DA---+-----                         *  STORE_LCL_VAR struct<Program+S, 16> V03 loc1         


Local V03 should not be enregistered because: written/read in a block op
lowering store lcl var/field (after):
N001 (???,???) [000002] -----+-----                    t2 =    CNS_INT   int    0
               [000012] D----------                   t12 =    LCL_ADDR  byref  V03 loc1         [+0]
                                                            /--*  t12    byref  
                                                            +--*  t2     int    
N002 (???,???) [000003] sA---+-----                         *  STORE_BLK struct<Program+S, 16> (init)


Local V03 should not be enregistered because: written/read in a block op
lowering return node
N001 (???,???) [000007] -----+-----                         *  RETURN    void  
============


Program:copyStruct(ptr) - NYI (Z:\runtime\src\coreclr\jit\lowerwasm.cpp:476 - NYI_WASM: IR not in a stackified form)
Z:\runtime\src\coreclr\jit\lowerwasm.cpp:476
Assertion failed 'NYI_WASM: IR not in a stackified form' in 'Program:copyStruct(ptr)' during 'Lowering nodeinfo' (IL size 17; hash 0xce1e49ee; MinOpts)

src/coreclr/jit/lowerwasm.cpp

Copilot

Pull request overview

This PR implements infrastructure for WebAssembly block store operations in the RyuJIT compiler. It adds support for lowering block copy and initialization operations to use WASM-specific memory.copy and memory.fill instructions.

Changes:

Adds LowerBlockStore implementation for WASM target to handle block copy and initialization operations
Introduces two new WASM instructions (memory_copy and memory_fill) and their associated instruction format (IF_MEMCPY)
Adds emitter support for encoding and displaying the new IF_MEMCPY instruction format

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.

File	Description
src/coreclr/jit/lowerwasm.cpp	Implements LowerBlockStore to handle GT_STORE_BLK and GT_INIT_BLK operations, with partial infrastructure for memory.copy and memory.fill
src/coreclr/jit/instrswasm.h	Adds memory_copy and memory_fill instruction definitions with their opcodes
src/coreclr/jit/emitfmtswasm.h	Defines the IF_MEMCPY instruction format for memory operations with two memory indices
src/coreclr/jit/emitwasm.cpp	Implements encoding, size calculation, and display logic for IF_MEMCPY instruction format

src/coreclr/jit/lowerwasm.cpp

src/coreclr/jit/instrswasm.h

src/coreclr/jit/lowerwasm.cpp

src/coreclr/jit/emitfmtswasm.h

src/coreclr/jit/emitwasm.cpp

Copilot

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

src/coreclr/jit/lowerwasm.cpp

src/coreclr/tools/Common/JitInterface/WasmLowering.cs

src/coreclr/jit/codegenwasm.cpp

Copilot

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated no new comments.

kg · 2026-02-18T06:21:43Z

cc @adamperlin see the WasmLowering.GetSignature changes. I couldn't figure out what was wrong with the existing implementation so I rewrote it, but the rewrite isn't complete. It was generating signatures with zeroes in them and that produced invalid wasm modules.

AndyAyersMS · 2026-02-18T14:58:23Z

I couldn't figure out what was wrong with the existing implementation so I rewrote it, but the rewrite isn't complete. It was generating signatures with zeroes in them and that produced invalid wasm modules.

That's probably my fault: I revised that code to try and handle the return buffer placement.

@MichalStrehovsky in the managed type system signatures is the this always explicitly represented?

MichalStrehovsky · 2026-02-19T05:46:18Z

@MichalStrehovsky in the managed type system signatures is the this always explicitly represented?

If you mean the MethodSignature class, it represents what the input ECMA-335 has. So:

!MethodSignature.IsStatic && !MethodSignature.IsExplicitThis: there's an implicit this parameter not listed in the signature
!MethodSignature.IsStatic && MethodSignature.IsExplicitThis: this is part of the signature (can be hit in obscure cases involving C++/CLI when the compiler wants to attach modifiers to this, likely not a concern for WASM targets)
MethodSignature.IsStatic: static method, no this for obvious reasons

src/coreclr/tools/Common/JitInterface/WasmLowering.cs

adamperlin · 2026-02-19T22:28:50Z

cc @adamperlin see the WasmLowering.GetSignature changes. I couldn't figure out what was wrong with the existing implementation so I rewrote it, but the rewrite isn't complete. It was generating signatures with zeroes in them and that produced invalid wasm modules.

The re-write looks good to me, appending to a list seems like an easier solution to ensure correctness. My only feedback would just be that we should probably add a comment (maybe in the header) explaining what the maximum number of parameters we might add when lowering the signature is (explaining the + 4 in the allocated signature list size).

Copilot

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/coreclr/jit/lowerwasm.cpp:484

The DEBUG logging should use JITDUMP/JITDUMPEXEC instead of raw printf to be consistent with existing JIT logging patterns. The suggested approach is to use JITDUMP("node==[%06u] prev==[%06u]\n", Compiler::dspTreeID(node), Compiler::dspTreeID(prev)); which eliminates the need for the #ifdef DEBUG wrapper.


                    JITDUMP("node==[%06u] prev==[%06u]\n", Compiler::dspTreeID(node), Compiler::dspTreeID(prev));
                    NYI_WASM("IR not in a stackified form");
                }

                // In stack order, the last operand is closest to its parent, thus put on top here.
                node->VisitOperands([stack](GenTree* operand) {
                    stack->Push(operand);
                    return GenTree::VisitResult::Continue;
                });

src/coreclr/tools/Common/JitInterface/WasmLowering.cs

kg · 2026-02-19T23:07:55Z

@dotnet/jit-contrib PTAL

AndyAyersMS

Looks good overall, just curious about the GC disabling part.

src/coreclr/jit/codegenwasm.cpp

Add insns for memory copy and fill Remove NYIs so stuff can flow through Cleanup Checkpoint Fix opcodes Fix WasmLowering.GetSignature Maybe-working codegen for zeroing a struct jit-format Remove unused local Consume operands Fix erroneous fallthrough Address PR feedback Remove dead call NotImplementedException ArrayBuilder and comment Make initblk loop work

Remove else case

src/coreclr/jit/emitfmtswasm.h

src/coreclr/jit/codegenwasm.cpp

src/coreclr/jit/lowerwasm.cpp

src/coreclr/jit/codegenwasm.cpp

src/coreclr/jit/gentree.cpp

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

Copilot

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

src/coreclr/jit/codegenwasm.cpp

src/coreclr/jit/lowerwasm.cpp

src/coreclr/jit/codegenwasm.cpp

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

Copilot

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

src/coreclr/jit/codegenwasm.cpp

kg · 2026-02-23T18:09:03Z

Resolving all comments to merge as-is. Issues will be fixed in follow-up PRs.

kg added arch-wasm WebAssembly architecture area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI labels Jan 28, 2026

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Error while retrieving client Settings for PipelineArtifact. HttpRequestException: nodename nor servname provided, or not known (vsblobprodcus3.vsblob.visualstudio.com:443) #96798

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[android][clr] No peer certificates when executing System.Net.Http.Functional.Tests on Android emulator #124526

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kg added 4 commits February 19, 2026 19:24

Only print stackified failure nodes when verbose

e902420

Improve logging

b1935c4

Remove else case

Remove gtBlkOpGcUnsafe handling

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kg force-pushed the wasm-blockstore branch from ab3fa66 to b9ac6d9 Compare February 20, 2026 08:43

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[Wasm RyuJit] fix some issues with calls #124679

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kg merged commit e5f7893 into dotnet:main Feb 23, 2026
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[main] Source code updates from dotnet/runtime dotnet/dotnet#5050

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