From 82b486fe9b02638d00cb3282a77dffaea157aa3c Mon Sep 17 00:00:00 2001
From: win7-7 <win7-7@users.noreply.github.com>
Date: Tue, 30 Dec 2025 06:25:00 +0200
Subject: [PATCH] 1337444 - wasm: runtime crash involving i64 globals

1337444: Fix regalloc of load/store i64 globals;
---
 js/src/jit/Lowering.cpp | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/js/src/jit/Lowering.cpp b/js/src/jit/Lowering.cpp
index 2ac1cd2602..c0ae566ae7 100644
--- a/js/src/jit/Lowering.cpp
+++ b/js/src/jit/Lowering.cpp
@@ -4244,22 +4244,37 @@ LIRGenerator::visitWasmBoundsCheck(MWasmBoundsCheck* ins)
 void
 LIRGenerator::visitWasmLoadGlobalVar(MWasmLoadGlobalVar* ins)
 {
-    LAllocation tlsPtr = useRegisterAtStart(ins->tlsPtr());
-    if (ins->type() == MIRType::Int64)
+    if (ins->type() == MIRType::Int64) {
+#ifdef JS_PUNBOX64
+        LAllocation tlsPtr = useRegisterAtStart(ins->tlsPtr());
+#else
+        LAllocation tlsPtr = useRegister(ins->tlsPtr());
+#endif
         defineInt64(new(alloc()) LWasmLoadGlobalVarI64(tlsPtr), ins);
-    else
+    } else {
+        LAllocation tlsPtr = useRegisterAtStart(ins->tlsPtr());
         define(new(alloc()) LWasmLoadGlobalVar(tlsPtr), ins);
+    }
 }
 
 void
 LIRGenerator::visitWasmStoreGlobalVar(MWasmStoreGlobalVar* ins)
 {
     MDefinition* value = ins->value();
-    LAllocation tlsPtr = useRegisterAtStart(ins->tlsPtr());
-    if (value->type() == MIRType::Int64)
-        add(new(alloc()) LWasmStoreGlobalVarI64(useInt64RegisterAtStart(value), tlsPtr), ins);
-    else
-        add(new(alloc()) LWasmStoreGlobalVar(useRegisterAtStart(value), tlsPtr), ins);
+    if (value->type() == MIRType::Int64) {
+#ifdef JS_PUNBOX64
+        LAllocation tlsPtr = useRegisterAtStart(ins->tlsPtr());
+        LInt64Allocation valueAlloc = useInt64RegisterAtStart(value);
+#else
+        LAllocation tlsPtr = useRegister(ins->tlsPtr());
+        LInt64Allocation valueAlloc = useInt64Register(value);
+#endif
+        add(new(alloc()) LWasmStoreGlobalVarI64(valueAlloc, tlsPtr), ins);
+    } else {
+        LAllocation tlsPtr = useRegisterAtStart(ins->tlsPtr());
+        LAllocation valueAlloc = useRegisterAtStart(value);
+        add(new(alloc()) LWasmStoreGlobalVar(valueAlloc, tlsPtr), ins);
+    }
 }
 
 void