Fix StdVBoolImplementation to handle large vectors

[tberghammer]

Summary

Fix StdVBoolImplementation to handle large vectors

The previous implementation only read out the first element of the underlying storage array. Because of it only the first 32 (on x86) or the first 64 (on x86_64) element was displayed.

[sivachandra]

LGTM. Thanks for doing this.

lldb/trunk/examples/synthetic/gnu_libstdcpp.py

def num_children(self):
           return (finish - start) * 8 + offset
       return 0
 
     def get_child_at_index(self, index):
       if index >= self.num_children():
         return None
       byte_offset = index / 8
       bit_offset = index % 8
-      data = self.start_p.GetPointeeData()
-      bit = data.GetUnsignedInt8(lldb.SBError(), byte_offset) & (1 << bit_offset)
+      element_size = self.start_p.GetType().GetPointeeType().GetByteSize()
+      data = self.start_p.GetPointeeData(byte_offset / element_size)
+      bit = data.GetUnsignedInt8(lldb.SBError(), byte_offset % element_size) & (1 << bit_offset)
       if bit != 0:
         value_expr = "(bool)true"
       else:
         value_expr = "(bool)false"
       return self.valobj.CreateValueFromExpression("[%d]" % index, value_expr)
 
     def update(self):
       try:

lldb/trunk/test/functionalities/data-formatter/data-formatter-stl/libstdcpp/vbool/TestDataFormatterStdVBool.py

def test_with_dsym_and_run_command(self):
         """Test data formatter commands."""
         self.buildDsym()
         self.data_formatter_commands()
 
     @expectedFailureFreeBSD("llvm.org/pr20548") # fails to build on lab.llvm.org buildbot
     @dwarf_test
     @skipIfWindows # http://llvm.org/pr21800
     @skipIfDarwin
-    @expectedFailurei386 #xfail to get buildbot green, failing config: i386 binary running on ubuntu 14.04 x86_64
     def test_with_dwarf_and_run_command(self):
         """Test data formatter commands."""
         self.buildDwarf()
         self.data_formatter_commands()
 
     def setUp(self):
         # Call super's setUp().
         TestBase.setUp(self)