Prefill pre-allocated memory of folded allocation with one pointer fillers when heap verifier is on.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 9900a1e9848f0515b093bb423c4b212de5e81fb2..db97966a9aad7aa2fb0855623151a8f8f60bceb5 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -5369,6 +5369,25 @@ void LCodeGen::DoAllocate(LAllocate* instr) {
   }
 
   __ bind(deferred->exit());
+
+  if (instr->hydrogen()->MustPrefillWithFiller()) {
+    if (instr->size()->IsConstantOperand()) {
+      int32_t size = ToInteger32(LConstantOperand::cast(instr->size()));
+      __ mov(scratch, Operand(size));
+    } else {
+      scratch = ToRegister(instr->size());
+    }
+    __ sub(scratch, scratch, Operand(kPointerSize));
+    __ sub(result, result, Operand(kHeapObjectTag));
+    Label loop;
+    __ bind(&loop);
+    __ mov(scratch2, Operand(isolate()->factory()->one_pointer_filler_map()));
+    __ str(scratch2, MemOperand(result, scratch));
+    __ sub(scratch, scratch, Operand(kPointerSize));
+    __ cmp(scratch, Operand(0));
+    __ b(ge, &loop);
+    __ add(result, result, Operand(kHeapObjectTag));
+  }
 }