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

lldb/source/API/SBThread.cpp

@@ -19,6 +19,7 @@
 #include "lldb/Core/State.h"
 #include "lldb/Core/Stream.h"
 #include "lldb/Core/StreamFile.h"
+#include "lldb/Core/StructuredData.h"
 #include "lldb/Interpreter/CommandInterpreter.h"
 #include "lldb/Target/SystemRuntime.h"
 #include "lldb/Target/Thread.h"
@@ -589,6 +590,74 @@ SBThread::GetQueueID () const
     return id;
 }
 
+bool
+SBThread::GetInfoItemByPathAsString (const char *path, SBStream &strm)
+{
+    Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
+    bool success = false;
+    Mutex::Locker api_locker;
+    ExecutionContext exe_ctx (m_opaque_sp.get(), api_locker);
+
+    if (exe_ctx.HasThreadScope())
+    {
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
+        {
+            Thread *thread = exe_ctx.GetThreadPtr();
+            StructuredData::ObjectSP info_root_sp = thread->GetExtendedInfo();
+            if (info_root_sp)
+            {
+                StructuredData::ObjectSP node = info_root_sp->GetObjectForDotSeparatedPath (path);
+                if (node)
+                {
+                    if (node->GetType() == StructuredData::Type::eTypeString)
+                    {
+                        strm.Printf ("%s", node->GetAsString()->GetValue().c_str());
+                        success = true;
+                    }
+                    if (node->GetType() == StructuredData::Type::eTypeInteger)
+                    {
+                        strm.Printf ("0x%" PRIx64, node->GetAsInteger()->GetValue());
+                        success = true;
+                    }
+                    if (node->GetType() == StructuredData::Type::eTypeFloat)
+                    {
+                        strm.Printf ("0x%f", node->GetAsFloat()->GetValue());
+                        success = true;
+                    }
+                    if (node->GetType() == StructuredData::Type::eTypeBoolean)
+                    {
+                        if (node->GetAsBoolean()->GetValue() == true)
+                            strm.Printf ("true");
+                        else
+                            strm.Printf ("false");
+                        success = true;
+                    }
+                    if (node->GetType() == StructuredData::Type::eTypeNull)
+                    {
+                        strm.Printf ("null");
+                        success = true;
+                    }
+                }
+            }
+        }
+        else
+        {
+            if (log)
+                log->Printf ("SBThread(%p)::GetInfoItemByPathAsString() => error: process is running",
+                             static_cast<void*>(exe_ctx.GetThreadPtr()));
+        }
+    }
+
+    if (log)
+        log->Printf ("SBThread(%p)::GetInfoItemByPathAsString () => %s",
+                     static_cast<void*>(exe_ctx.GetThreadPtr()),
+                     strm.GetData());
+
+    return success;
+}
+
+
 SBError
 SBThread::ResumeNewPlan (ExecutionContext &exe_ctx, ThreadPlan *new_plan)
 {