Show error message from failed evaluation when doing -var-create

[ki.stfu]

Summary

When -var-create fails, we will now show the error message from the failed evaluation if it is available.

Patch from [e-mail]

[ki.stfu]

Rebase against ToT

[ki.stfu]

Minor fixes

[ChuckR]

Thank you.

test/tools/lldb-mi/variable/TestMiVar.py

def test_lldbmi_eval(self):
         self.runCmd("-break-insert main.cpp:%d" % line)
         self.expect("\^done,bkpt={number=\"1\"")
         self.runCmd("-exec-run")
         self.expect("\^running")
         self.expect("\*stopped,reason=\"breakpoint-hit\"")
 
         # Print non-existant variable
         self.runCmd("-var-create var1 * undef")
-        self.expect("\^error,msg=\"Failed to create variable object for 'undef'\"")
+        self.expect("\^error,msg=\"error: error: use of undeclared identifier \'undef\'\s+error: 1 errors parsing expression\"")
         self.runCmd("-data-evaluate-expression undef")
         self.expect("\^error,msg=\"Could not evaluate expression\"")
 
         # Print global "g_MyVar", modify, delete and create again
         self.runCmd("-data-evaluate-expression g_MyVar")
         self.expect("\^done,value=\"3\"")
         self.runCmd("-var-create var2 * g_MyVar")
         self.expect("\^done,name=\"var2\",numchild=\"0\",value=\"3\",type=\"int\",thread-id=\"1\",has_more=\"0\"")

tools/lldb-mi/MICmdCmdVar.cpp

if (value.IsValid() && value.GetError().Success())
         m_bValid = true;
         m_nChildren = value.GetNumChildren();
         m_strType = CMICmnLLDBUtilSBValue(value).GetTypeNameDisplay();
 
         // This gets added to CMICmnLLDBDebugSessionInfoVarObj static container of varObjs
         CMICmnLLDBDebugSessionInfoVarObj varObj(rStrExpression, m_strVarName, value);
         m_strValue = varObj.GetValueFormatted();
     }
+    else 
+    {
+        lldb::SBStream err;
+        if (value.GetError().GetDescription(err))
+            m_strValue = err.GetData();
+    }
 
     return MIstatus::success;
 }
 
 //++ ------------------------------------------------------------------------------------
 // Details: The invoker requires this function. The command prepares a MI Record Result
 //          for the work carried out in the Execute().
 // Type:    Overridden.
if (m_bValid)
         miValueResultAll.Add("has_more", miValueConst6);
 
         const CMICmnMIResultRecord miRecordResult(m_cmdData.strMiCmdToken, CMICmnMIResultRecord::eResultClass_Done, miValueResultAll);
         m_miResultRecord = miRecordResult;
 
         return MIstatus::success;
     }
 
-    const CMICmnMIValueConst miValueConst(CMIUtilString::Format(MIRSRC(IDS_CMD_ERR_VARIABLE_CREATION_FAILED), m_strExpression.c_str()));
+    CMIUtilString strErrMsg(m_strValue);
+    if (m_strValue.empty())
+        strErrMsg = CMIUtilString::Format(MIRSRC(IDS_CMD_ERR_VARIABLE_CREATION_FAILED), m_strExpression.c_str());
+    const CMICmnMIValueConst miValueConst(strErrMsg);
     CMICmnMIValueResult miValueResult("msg", miValueConst);
     const CMICmnMIResultRecord miRecordResult(m_cmdData.strMiCmdToken, CMICmnMIResultRecord::eResultClass_Error, miValueResult);
     m_miResultRecord = miRecordResult;
 
     return MIstatus::success;
 }
 
 //++ ------------------------------------------------------------------------------------