Another question about JEP 270: Reserved Stack Areas for Critical Sections

[Andrew Haley]

In interp_masm_x86.cpp I see:

void InterpreterMacroAssembler::remove_activation(
	...
    cmpptr(rbx, Address(rthread, JavaThread::reserved_stack_activation_offset()));
    jcc(Assembler::lessEqual, no_reserved_zone_enabling);

    call_VM_leaf(
      CAST_FROM_FN_PTR(address, SharedRuntime::enable_stack_reserved_zone), rthread);
    push(rthread);
    call_VM(noreg, CAST_FROM_FN_PTR(address,
                   InterpreterRuntime::throw_delayed_StackOverflowError));
    should_not_reach_here();

What does push(rthread) do?

Thanks,

Andrew.