Improve test for Intel(R) MPX registers.

[valentinagiusti]

Summary

Let the inferior test code determine if CPU and kernel support Intel(R)
MPX and cleanup test script.

Signed-off-by: Valentina Giusti <[e-mail]>

lldb/trunk/packages/Python/lldbsuite/test/functionalities/register/intel_xtended_registers/TestMPXRegisters.py

 """
-Test the MPX registers.
+Test the Intel(R) MPX registers.
 """
 
 from __future__ import print_function
 
 
 import os
 import sys
 import time
 import re
 import lldb
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
 from lldbsuite.test import lldbutil
 
 
 class RegisterCommandsTestCase(TestBase):
 
     mydir = TestBase.compute_mydir(__file__)
 
     def setUp(self):
         TestBase.setUp(self)
-        self.has_teardown = False
-
-    def tearDown(self):
-        self.dbg.GetSelectedTarget().GetProcess().Destroy()
-        TestBase.tearDown(self)
 
     @skipIf(compiler="clang")
-    @skipIf(oslist=["linux"], compiler="gcc", compiler_version=["<", "5"]) #GCC version >= 5 supports MPX.
     @skipIf(oslist=no_match(['linux']))
     @skipIf(archs=no_match(['i386', 'x86_64']))
+    @skipIf(oslist=["linux"], compiler="gcc", compiler_version=["<", "5"]) #GCC version >= 5 supports Intel(R) MPX.
     def test_mpx_registers_with_example_code(self):
-        """Test MPX registers with example code."""
+        """Test Intel(R) MPX registers with example code."""
         self.build()
         self.mpx_registers_with_example_code()
 
     def mpx_registers_with_example_code(self):
-        """Test MPX registers after running example code."""
+        """Test Intel(R) MPX registers after running example code."""
         self.line = line_number('main.cpp', '// Set a break point here.')
 
         exe = os.path.join(os.getcwd(), "a.out")
         self.runCmd("file " + exe, CURRENT_EXECUTABLE_SET)
 
         lldbutil.run_break_set_by_file_and_line(self, "main.cpp", self.line, num_expected_locations=1)
         self.runCmd("run", RUN_SUCCEEDED)
 
         target = self.dbg.GetSelectedTarget()
         process = target.GetProcess()
 
         if (process.GetState() == lldb.eStateExited):
-            self.skipTest("HW doesn't support MPX feature.")
+            self.skipTest("Intel(R) MPX is not supported.")
         else:
             self.expect("thread backtrace", STOPPED_DUE_TO_BREAKPOINT,
                         substrs = ["stop reason = breakpoint 1."])
 
         if self.getArchitecture() == 'x86_64':
             self.expect("register read -s 3",
                         substrs = ['bnd0 = {0x0000000000000010 0xffffffffffffffe6}',
                                    'bnd1 = {0x0000000000000020 0xffffffffffffffd6}',

lldb/trunk/packages/Python/lldbsuite/test/functionalities/register/intel_xtended_registers/main.cpp

 //===-- main.cpp ------------------------------------------------*- C++ -*-===//
 ////
 ////                     The LLVM Compiler Infrastructure
 ////
 //// This file is distributed under the University of Illinois Open Source
 //// License. See LICENSE.TXT for details.
 ////
 ////===----------------------------------------------------------------------===//
 //
 
 #include <cpuid.h>
 #include <cstddef>
 
 int
 main(int argc, char const *argv[])
 {
-    unsigned int rax, rbx, rcx, rdx;
-
-    // Check if XSAVE is enabled.
-    if (!__get_cpuid(1, &rax, &rbx, &rcx, &rdx) || (rcx & bit_OSXSAVE) != bit_OSXSAVE)
-        return -1;
-
-    // Check if MPX is enabled.
-    if (__get_cpuid_max(0, NULL) > 7)
-    {
-        __cpuid_count(7, 0, rax, rbx, rcx, rdx);
-        if ((rbx & bit_MPX) != bit_MPX)
-            return -1;
-    }
-    else
+    // This call returns 0 only if the CPU and the kernel support Intel(R) MPX.
+    if (prctl(PR_MPX_ENABLE_MANAGEMENT, 0, 0, 0, 0) != 0)
         return -1;
 
-// Run MPX test code.
+// Run Intel(R) MPX test code.
 #if defined(__x86_64__)
     asm("mov $16, %rax\n\t"
         "mov $9, %rdx\n\t"
         "bndmk (%rax,%rdx), %bnd0\n\t"
         "mov $32, %rax\n\t"
         "mov $9, %rdx\n\t"
         "bndmk (%rax,%rdx), %bnd1\n\t"
         "mov $48, %rax\n\t"