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[wasm] Implement MONO_MEMORY_BARRIER in jiterpreter #107325

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merged 6 commits into from
Sep 6, 2024
+19 −2
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[wasm] Implement MONO_MEMORY_BARRIER in jiterpreter #107325

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054bb52
Implement MONO_MEMORY_BARRIER in jiterpreter
kg Sep 3, 2024
08ac691
Don't emit memory barrier in ST builds
kg Sep 4, 2024
7b171b2
Enable jiterp traces for MT wasm
kg Sep 4, 2024
5a9b7b7
Use native wasm atomic fence instead of calling C for memory barriers
kg Sep 5, 2024
8de6f60
Fix atomic fence encoding
kg Sep 6, 2024
204563c
Update comment
kg Sep 6, 2024
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6 changes: 5 additions & 1 deletion src/mono/browser/runtime/jiterpreter-trace-generator.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -3977,8 +3977,12 @@ function emit_atomics (
builder: WasmBuilder, ip: MintOpcodePtr, opcode: number
) {
if (opcode === MintOpcode.MINT_MONO_MEMORY_BARRIER) {
if (WasmEnableThreads)
if (WasmEnableThreads) {
builder.appendAtomic(WasmAtomicOpcode.atomic_fence);
// The text format and other parts of the spec say atomic.fence has no operands,
// but the binary encoding requires a dummy zero byte for some reason
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It's for the memory ordering. See this part of the shared everythign threads proposal. 0 means sequential consistency, 1 will mean acquire-release https://github.com/WebAssembly/shared-everything-threads/blob/main/proposals/shared-everything-threads/Overview.md#memory-orderings

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And sync_synchronize is sequential consistency, right?

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And sync_synchronize is sequential consistency, right?

It's a "full barrier" which presumably means seq cst. https://gcc.gnu.org/onlinedocs/gcc/_005f_005fsync-Builtins.html

builder.appendU8(0);
}
return true;
}

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