Correction in TestFrames.py test for arm targets in thumb mode

[omjavaid]

Summary

This patch adds required correction in TestFrames.py for arm targets in thumb mode.

On arm hardware thumb mode is identified by setting the least significant bit. In such case when we read PC we ll end up getting an unaligned address which has last bit set and will cause a mismatch between address read from dwarf frame information. I have corrected this by adding an appropriate check in TestFrames.py.

[tberghammer]

LGTM

Note: We will have to enable the same functionality for some variant of mips also but I don't know the details so we should leave it for the mips guys.

lldb/trunk/packages/Python/lldbsuite/test/python_api/frame/TestFrames.py

def test_get_arg_vals_for_call_stack(self):
                                                   val.GetValue()))
                 print("%s(%s)" % (name, ", ".join(argList)), file=session)
                 
                 # Also check the generic pc & stack pointer.  We can't test their absolute values,
                 # but they should be valid.  Uses get_GPRs() from the lldbutil module.
                 gpr_reg_set = lldbutil.get_GPRs(frame)
                 pc_value = gpr_reg_set.GetChildMemberWithName("pc")
                 self.assertTrue (pc_value, "We should have a valid PC.")
-                pc_value_str = pc_value.GetValue()
-                self.assertTrue (pc_value_str, "We should have a valid PC string.")
-                self.assertTrue (int(pc_value_str, 0) == frame.GetPC(), "PC gotten as a value should equal frame's GetPC")
+                pc_value_int = int(pc_value.GetValue(), 0)
+                # Make sure on arm targets we dont mismatch PC value on the basis of thumb bit.
+                # Frame PC will not have thumb bit set in case of a thumb instruction as PC.
+                if self.getArchitecture() in ['arm']:
+                    pc_value_int &= ~1
+                self.assertTrue (pc_value_int == frame.GetPC(), "PC gotten as a value should equal frame's GetPC")
                 sp_value = gpr_reg_set.GetChildMemberWithName("sp")
                 self.assertTrue (sp_value, "We should have a valid Stack Pointer.")
                 self.assertTrue (int(sp_value.GetValue(), 0) == frame.GetSP(), "SP gotten as a value should equal frame's GetSP")
 
             print("---", file=session)
             process.Continue()
 
         # At this point, the inferior process should have exited.