7167254: Crash on OSX in Enumerator.nextElement() with compressed oops

Summary: null checks in "compressed oops with base" mode may trigger a SIGBUS rather than a SIGSEGV.
Reviewed-by: dsamersoff, dcubed, rbackman, kvn

src/os_cpu/bsd_x86/vm/os_bsd_x86.cpp

@@ -522,11 +522,12 @@ JVM_handle_bsd_signal(int sig,
 
       if ((sig == SIGSEGV || sig == SIGBUS) && os::is_poll_address((address)info->si_addr)) {
         stub = SharedRuntime::get_poll_stub(pc);
-#if defined(__APPLE__) && !defined(AMD64)
+#if defined(__APPLE__)
       // 32-bit Darwin reports a SIGBUS for nearly all memory access exceptions.
+      // 64-bit Darwin may also use a SIGBUS (seen with compressed oops).
       // Catching SIGBUS here prevents the implicit SIGBUS NULL check below from
       // being called, so only do so if the implicit NULL check is not necessary.
-      } else if (sig == SIGBUS && MacroAssembler::needs_explicit_null_check((int)info->si_addr)) {
+      } else if (sig == SIGBUS && MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
 #else
       } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
 #endif