lldb: To allow cross-compilation of Linux/ProcessMonitor.cpp, hide PC-related stuff behind #ifdef's

[pawelo]

Summary

To allow cross-compilation of Linux/ProcessMonitor.cpp, hide PC-related stuff behind #ifdef's. Note that struct user used in affected code has a field named i387 which is x86-specific, therefore it should be compiled only for PC.

[tfiala]

Hey Paul,

Am I understanding you correctly that you are trying to cross compile this
for Linux on a non-Linux box?

-Todd

[tfiala]

Looking at this now.

[tfiala]

Submitted:
Sending source/Plugins/Process/Linux/ProcessMonitor.cpp
Transmitting file data .
Committed revision 211026.

I made minor tweaks to the comment. Trying to keep with our goal of starting sentences upper cased, ending with periods, and adjusted PC reference to x86-based system.

source/Plugins/Process/Linux/ProcessMonitor.cpp

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())
     {
+#if defined(__i386__) || defined(__x86_64__)
+    // note that struct user used below has field named i387 which is x86-specific
+    // therefore case below should be compiled only for PC
     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__
         gs_user_offset += offsetof(struct user_regs_struct, gs);
 #endif
 #ifdef __i386__
#endif
         }
 
         // Read the LDT base for that selector.
         uint32_t tmp[4];
         m_result = (PTRACE(PTRACE_GET_THREAD_AREA, m_tid, (void *)(gs >> 3), &tmp, 0) == 0);
         *m_addr = tmp[1];
         break;
     }
+#endif
     case llvm::Triple::x86_64:
         // Read the FS register base.
         m_result = (PTRACE(PTRACE_ARCH_PRCTL, m_tid, m_addr, (void *)ARCH_GET_FS, 0) == 0);
         break;
     default:
         m_result = false;
         break;
     }