8360776: Enable -XX:+UseAPX as experimental feature in all builds

Author: vamsi-parasa

src/hotspot/cpu/x86/vm_version_x86.cpp

@@ -440,7 +440,6 @@ class VM_Version_StubGenerator: public StubCodeGenerator {
     __ andl(rax, Address(rbp, in_bytes(VM_Version::xem_xcr0_offset()))); // xcr0 bits apx_f
     __ jcc(Assembler::equal, vector_save_restore);
 
-#ifndef PRODUCT
     bool save_apx = UseAPX;
     VM_Version::set_apx_cpuFeatures();
     UseAPX = true;
@@ -457,7 +456,6 @@ class VM_Version_StubGenerator: public StubCodeGenerator {
     __ movq(Address(rsi, 8), r31);
 
     UseAPX = save_apx;
-#endif
     __ bind(vector_save_restore);
     //
     // Check if OS has enabled XGETBV instruction to access XCR0
@@ -1022,8 +1020,6 @@ void VM_Version::get_processor_features() {
   if (UseAPX && !apx_supported) {
     warning("UseAPX is not supported on this CPU, setting it to false");
     FLAG_SET_DEFAULT(UseAPX, false);
-  } else if (FLAG_IS_DEFAULT(UseAPX)) {
-    FLAG_SET_DEFAULT(UseAPX, apx_supported ? true : false);
   }
 
   if (!UseAPX) {
@@ -3151,17 +3147,11 @@ bool VM_Version::os_supports_apx_egprs() {
   if (!supports_apx_f()) {
     return false;
   }
-  // Enable APX support for product builds after
-  // completion of planned features listed in JDK-8329030.
-#if !defined(PRODUCT)
   if (_cpuid_info.apx_save[0] != egpr_test_value() ||
       _cpuid_info.apx_save[1] != egpr_test_value()) {
     return false;
   }
   return true;
-#else
-  return false;
-#endif
 }
 
 uint VM_Version::cores_per_cpu() {

src/hotspot/os/windows/os_windows.cpp

@@ -2623,15 +2623,13 @@ LONG WINAPI topLevelExceptionFilter(struct _EXCEPTION_POINTERS* exceptionInfo) {
     return Handle_Exception(exceptionInfo, VM_Version::cpuinfo_cont_addr());
   }
 
-#if !defined(PRODUCT)
   if ((exception_code == EXCEPTION_ACCESS_VIOLATION) &&
       VM_Version::is_cpuinfo_segv_addr_apx(pc)) {
     // Verify that OS save/restore APX registers.
     VM_Version::clear_apx_test_state();
     return Handle_Exception(exceptionInfo, VM_Version::cpuinfo_cont_addr_apx());
   }
 #endif
-#endif
 
 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
   if (VMError::was_assert_poison_crash(exception_record)) {

src/hotspot/os_cpu/bsd_x86/os_bsd_x86.cpp

@@ -429,13 +429,11 @@ bool PosixSignals::pd_hotspot_signal_handler(int sig, siginfo_t* info,
       stub = VM_Version::cpuinfo_cont_addr();
     }
 
-#if !defined(PRODUCT) && defined(_LP64)
     if ((sig == SIGSEGV || sig == SIGBUS) && VM_Version::is_cpuinfo_segv_addr_apx(pc)) {
       // Verify that OS save/restore APX registers.
       stub = VM_Version::cpuinfo_cont_addr_apx();
       VM_Version::clear_apx_test_state();
     }
-#endif
 
     // We test if stub is already set (by the stack overflow code
     // above) so it is not overwritten by the code that follows. This

src/hotspot/os_cpu/linux_x86/os_linux_x86.cpp

@@ -255,13 +255,11 @@ bool PosixSignals::pd_hotspot_signal_handler(int sig, siginfo_t* info,
       stub = VM_Version::cpuinfo_cont_addr();
     }
 
-#if !defined(PRODUCT) && defined(_LP64)
     if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr_apx(pc)) {
       // Verify that OS save/restore APX registers.
       stub = VM_Version::cpuinfo_cont_addr_apx();
       VM_Version::clear_apx_test_state();
     }
-#endif
 
     if (thread->thread_state() == _thread_in_Java) {
       // Java thread running in Java code => find exception handler if any