Initial merge of some of the iOS 8 / Mac OS X Yosemite specific
lldb support.  I'll be doing more testing & cleanup but I wanted to
get the initial checkin done.

This adds a new SBExpressionOptions::SetLanguage API for selecting a
language of an expression.

I added adds a new SBThread::GetInfoItemByPathString for retriving
information about a thread from that thread's StructuredData.

I added a new StructuredData class for representing
key-value/array/dictionary information (e.g. JSON formatted data).
Helper functions to read JSON and create a StructuredData object,
and to print a StructuredData object in JSON format are included.

A few Cocoa / Cocoa Touch data formatters were updated by Enrico
to track changes in iOS 8 / Yosemite.

Before we query a thread's extended information, the system runtime may 
provide hints to the remote debug stub that it will use to retrieve values
out of runtime structures.  I added a new SystemRuntime method 
AddThreadExtendedInfoPacketHints which allows the SystemRuntime to add 
key-value type data to the initial request that we send to the remote stub.

The thread-format formatter string can now retrieve values out of a thread's
extended info structured data.  The default thread-format string picks up
two of these - thread.info.activity.name and thread.info.trace_messages.

I added a new "jThreadExtendedInfo" packet in debugserver; I will
add documentation to the lldb-gdb-remote.txt doc soon.  It accepts
JSON formatted arguments (most importantly, "thread":threadnum) and
it returns a variety of information regarding the thread to lldb
in JSON format.  This JSON return is scanned into a StructuredData
object that is associated with the thread; UI layers can query the
thread's StructuredData to see if key-values are present, and if
so, show them to the user.  These key-values are likely to be
specific to different targets with some commonality among many
targets.  For instance, many targets will be able to advertise the
pthread_t value for a thread.

I added an initial rough cut of "thread info" command which will print
the information about a thread from the jThreadExtendedInfo result.
I need to do more work to make this format reasonably.

Han Ming added calls into the pmenergy and pmsample libraries if
debugserver is run on Mac OS X Yosemite to get information about the
inferior's power use.

I added support to debugserver for gathering the Genealogy information
about threads, if it exists, and returning it in the jThreadExtendedInfo
JSON result.

llvm-svn: 210874
diff --git a/lldb/source/Target/Thread.cpp b/lldb/source/Target/Thread.cpp
index af5a9a4..400d992 100644
--- a/lldb/source/Target/Thread.cpp
+++ b/lldb/source/Target/Thread.cpp
@@ -292,7 +292,9 @@
     m_temporary_resume_state (eStateRunning),
     m_unwinder_ap (),
     m_destroy_called (false),
-    m_override_should_notify (eLazyBoolCalculate)
+    m_override_should_notify (eLazyBoolCalculate),
+    m_extended_info_fetched (false),
+    m_extended_info ()
 {
     Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
     if (log)
@@ -1709,6 +1711,9 @@
     if (m_curr_frames_sp && m_curr_frames_sp->GetAllFramesFetched())
         m_prev_frames_sp.swap (m_curr_frames_sp);
     m_curr_frames_sp.reset();
+
+    m_extended_info.reset();
+    m_extended_info_fetched = false;
 }
 
 lldb::StackFrameSP
@@ -2068,6 +2073,82 @@
     return num_frames_shown;
 }
 
+bool
+Thread::GetDescription (Stream &strm, lldb::DescriptionLevel level, bool print_json)
+{
+    DumpUsingSettingsFormat (strm, 0);
+    strm.Printf("\n");
+
+    StructuredData::ObjectSP thread_info = GetExtendedInfo();
+
+    if (thread_info && print_json)
+    {
+        thread_info->Dump (strm);
+        strm.Printf("\n");
+        return true;
+    }
+
+    if (thread_info)
+    {
+        StructuredData::ObjectSP activity = thread_info->GetObjectForDotSeparatedPath("activity");
+        StructuredData::ObjectSP breadcrumb = thread_info->GetObjectForDotSeparatedPath("breadcrumb");
+        StructuredData::ObjectSP messages = thread_info->GetObjectForDotSeparatedPath("trace_messages");
+
+        bool printed_activity = false;
+        if (activity && activity->GetType() == StructuredData::Type::eTypeDictionary)
+        {
+            StructuredData::Dictionary *activity_dict = activity->GetAsDictionary();
+            StructuredData::ObjectSP id = activity_dict->GetValueForKey("id");
+            StructuredData::ObjectSP name = activity_dict->GetValueForKey("name");
+            if (name && name->GetType() == StructuredData::Type::eTypeString
+                && id && id->GetType() == StructuredData::Type::eTypeInteger)
+            {
+                strm.Printf("  Activity '%s', 0x%" PRIx64 "\n", name->GetAsString()->GetValue().c_str(), id->GetAsInteger()->GetValue());
+            }
+            printed_activity = true;
+        }
+        bool printed_breadcrumb = false;
+        if (breadcrumb && breadcrumb->GetType() == StructuredData::Type::eTypeDictionary)
+        {
+            if (printed_activity)
+                strm.Printf ("\n");
+            StructuredData::Dictionary *breadcrumb_dict = breadcrumb->GetAsDictionary();
+            StructuredData::ObjectSP breadcrumb_text = breadcrumb_dict->GetValueForKey ("name");
+            if (breadcrumb_text && breadcrumb_text->GetType() == StructuredData::Type::eTypeString)
+            {
+                strm.Printf ("  Current Breadcrumb: %s\n", breadcrumb_text->GetAsString()->GetValue().c_str());
+            }
+            printed_breadcrumb = true;
+        }
+        if (messages && messages->GetType() == StructuredData::Type::eTypeArray)
+        {
+            if (printed_breadcrumb)
+                strm.Printf("\n");
+            StructuredData::Array *messages_array = messages->GetAsArray();
+            const size_t msg_count = messages_array->GetSize();
+            if (msg_count > 0)
+            {
+                strm.Printf ("  %zu trace messages:\n", msg_count);
+                for (size_t i = 0; i < msg_count; i++)
+                {
+                    StructuredData::ObjectSP message = messages_array->GetItemAtIndex(i);
+                    if (message && message->GetType() == StructuredData::Type::eTypeDictionary)
+                    {
+                        StructuredData::Dictionary *message_dict = message->GetAsDictionary();
+                        StructuredData::ObjectSP message_text = message_dict->GetValueForKey ("message");
+                        if (message_text && message_text->GetType() == StructuredData::Type::eTypeString)
+                        {
+                            strm.Printf ("    %s\n", message_text->GetAsString()->GetValue().c_str());
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    return true;
+}
+
 size_t
 Thread::GetStackFrameStatus (Stream& strm,
                              uint32_t first_frame,