lldb get thread area on ARM64

[pawelo]

Summary

I've found that AArch64 case is missing.

[tfiala]

Looking at this now.

[tfiala]

LGTM.

Tested:
Ubuntu 14.04 x86_64, clang-3.5-built lldb.

[tfiala]

svn commit
Sending source/Plugins/Process/Linux/ProcessMonitor.cpp
Transmitting file data .
Committed revision 216553.

source/Plugins/Process/Linux/ProcessMonitor.cpp

 #include "lldb/lldb-python.h"
 
 // C Includes
 #include <errno.h>
 #include <poll.h>
 #include <string.h>
 #include <stdint.h>
 #include <unistd.h>
+#include <elf.h>
 #include <sys/personality.h>
 #include <sys/ptrace.h>
 #include <sys/uio.h>
 #include <sys/socket.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/user.h>
 #include <sys/wait.h>
 
-#if defined (__arm64__) || defined (__aarch64__)
-// NT_PRSTATUS and NT_FPREGSET definition
-#include <elf.h>
-#endif
-
 // C++ Includes
 // Other libraries and framework includes
 #include "lldb/Core/Debugger.h"
 #include "lldb/Core/Error.h"
 #include "lldb/Core/RegisterValue.h"
 #include "lldb/Core/Scalar.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Target/Thread.h"
ReadThreadPointerOperation::Execute(ProcessMonitor *monitor)
 
     // The process for getting the thread area on Linux is
     // somewhat... obscure. There's several different ways depending on
     // what arch you're on, and what kernel version you have.
 
     const ArchSpec& arch = monitor->GetProcess().GetTarget().GetArchitecture();
     switch(arch.GetMachine())
     {
+    case llvm::Triple::aarch64:
+    {
+         int regset = NT_ARM_TLS;
+         struct iovec ioVec;
+
+         ioVec.iov_base = m_addr;
+         ioVec.iov_len = sizeof(lldb::addr_t);
+         if (PTRACE(PTRACE_GETREGSET, m_tid, &regset, &ioVec, ioVec.iov_len) < 0)
+           m_result = false;
+         else
+           m_result = true;
+         break;
+    }
 #if defined(__i386__) || defined(__x86_64__)
     // Note that struct user below has a field named i387 which is x86-specific.
     // Therefore, this case should be compiled only for x86-based systems.
     case llvm::Triple::x86:
     {
         // Find the GS register location for our host architecture.
         size_t gs_user_offset = offsetof(struct user, regs);
 #ifdef __x86_64__