[wasm] Implement MONO_MEMORY_BARRIER in jiterpreter & enable MT jiterp traces (#107325)

* Implement MONO_MEMORY_BARRIER in jiterpreter
* Enable jiterp traces for MT wasm

Author: kg

src/mono/browser/runtime/jiterpreter-trace-generator.ts

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+import WasmEnableThreads from "consts:wasmEnableThreads";
 import { MonoMethod } from "./types/internal";
 import { NativePointer } from "./types/emscripten";
 import {
@@ -9,7 +10,7 @@ import {
 } from "./memory";
 import {
     WasmOpcode, WasmSimdOpcode, WasmValtype,
-    getOpcodeName, MintOpArgType
+    getOpcodeName, MintOpArgType, WasmAtomicOpcode
 } from "./jiterpreter-opcodes";
 import {
     MintOpcode, SimdInfo,
@@ -3975,6 +3976,20 @@ function emit_simd_4 (builder: WasmBuilder, ip: MintOpcodePtr, index: SimdIntrin
 function emit_atomics (
     builder: WasmBuilder, ip: MintOpcodePtr, opcode: number
 ) {
+    if (opcode === MintOpcode.MINT_MONO_MEMORY_BARRIER) {
+        if (WasmEnableThreads) {
+            // Mono memory barriers use sync_synchronize which generates atomic.fence on clang,
+            //  provided you pass -pthread at compile time
+            builder.appendAtomic(WasmAtomicOpcode.atomic_fence);
+            // The text format and other parts of the spec say atomic.fence has no operands,
+            //  but the binary encoding contains a byte specifying whether the barrier is
+            //  sequentially consistent (0) or acquire-release (1)
+            // Mono memory barriers are sync_synchronize which is sequentially consistent.
+            builder.appendU8(0);
+        }
+        return true;
+    }
+
     if (!builder.options.enableAtomics)
         return false;
 

src/mono/mono/mini/interp/jiterpreter-opcode-values.h

@@ -187,6 +187,7 @@ OP(MINT_THROW, ABORT_OUTSIDE_BRANCH_BLOCK_NONE)
 OP(MINT_MOV_SRC_OFF, NORMAL)
 OP(MINT_MOV_DST_OFF, NORMAL)
 
+OP(MINT_MONO_MEMORY_BARRIER, NORMAL)
 OPRANGE(MINT_MONO_EXCHANGE_U1, MINT_MONO_EXCHANGE_I8, HIGH)
 OPRANGE(MINT_MONO_CMPXCHG_U1, MINT_MONO_CMPXCHG_I8, HIGH)
 

src/mono/mono/mini/interp/jiterpreter.c

@@ -1165,6 +1165,7 @@ mono_jiterp_stelem_ref (
 	return 1;
 }
 
+
 // keep in sync with jiterpreter-enums.ts JiterpMember
 enum {
 	JITERP_MEMBER_VT_INITIALIZED = 0,

src/mono/mono/utils/options-def.h

@@ -89,7 +89,7 @@ DEFINE_BOOL(jiterpreter_jit_call_enabled, "jiterpreter-jit-call-enabled", TRUE,
 DEFINE_BOOL(wasm_gc_safepoints, "wasm-gc-safepoints", FALSE, "Use GC safepoints on WASM")
 #else
 // traces_enabled controls whether the jiterpreter will JIT individual interpreter opcode traces
-DEFINE_BOOL_READONLY(jiterpreter_traces_enabled, "jiterpreter-traces-enabled", FALSE, "JIT interpreter opcode traces into WASM")
+DEFINE_BOOL(jiterpreter_traces_enabled, "jiterpreter-traces-enabled", TRUE, "JIT interpreter opcode traces into WASM")
 // interp_entry_enabled controls whether specialized interp_entry wrappers will be jitted
 DEFINE_BOOL_READONLY(jiterpreter_interp_entry_enabled, "jiterpreter-interp-entry-enabled", FALSE, "JIT specialized WASM interp_entry wrappers")
 // jit_call_enabled controls whether do_jit_call will use specialized trampolines for hot call sites