Request for review (XS): 8003878: compiler/7196199 test failed on OS X since 8b54, jdk7u12b01

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/8003878/webrev

Limit vectors size to 16 bytes on OS X until it fixes restoration of 
upper 128bit of YMM registers on return from signal handler. I did it 
for all BSD OSs since I don't have them and I can verify their behavior.

Note, in my last experiment I short-cut signal processing in 
JVM_handle_bsd_signal. Instead of executing safepoint blob I set address 
of next instruction after safepoint in compiled code and return from 
signal handle there:

        if ((sig == SIGSEGV || sig == SIGBUS) && 
os::is_poll_address((address)info->si_addr)) {
          stub = SharedRuntime::get_poll_stub(pc);
+        if (stub != NULL & UseNewCode) {
+          uc->context_pc += 6;
+          return true;
+        }

But I still see that upper YMM bits are not restored. Also, I examined 
saved ucontext data (passed to JVM_handle_bsd_signal) and I see saved 
upper bits there. Something wrong with return from signal handler.

Thanks,
Vladimir