Bug 1288944 - Baldr: fix TLS propagation in i64 case (r=jolesen)

MozReview-Commit-ID: GC8K6R5elHp

--HG--
extra : rebase_source : c6c6310be1506aeea321de9623105904fe6ff188

js/src/jit/Lowering.cpp

@@ -4144,6 +4144,11 @@ LIRGenerator::visitAsmJSReturn(MAsmJSReturn* ins)
 
     if (rval->type() == MIRType::Int64) {
         LAsmJSReturnI64* lir = new(alloc()) LAsmJSReturnI64(useInt64Fixed(rval, ReturnReg64));
+
+        // Preserve the TLS pointer we were passed in `WasmTlsReg`.
+        MDefinition* tlsPtr = ins->getOperand(1);
+        lir->setOperand(INT64_PIECES, useFixed(tlsPtr, WasmTlsReg));
+
         add(lir);
         return;
     }

js/src/jit/shared/LIR-shared.h

@@ -8234,7 +8234,7 @@ class LAsmJSReturn : public LInstructionHelper<0, 2, 0>
     LIR_HEADER(AsmJSReturn);
 };
 
-class LAsmJSReturnI64 : public LInstructionHelper<0, INT64_PIECES, 0>
+class LAsmJSReturnI64 : public LInstructionHelper<0, INT64_PIECES + 1, 0>
 {
   public:
     LIR_HEADER(AsmJSReturnI64)