Fix problem where 32-bit statically built lldb-platform cannot find lldb-gdbserver.

[chaoren]

Summary

Adding x86 to supported architectures on x86_64.

Failsafe directory for shared objects and support executables.

[ovyalov]

Please see my comments.

source/Host/linux/HostInfoLinux.cpp

228

Could you check return value of HostInfoPosix::ComputeSharedLibraryDirectory?
You may return true immediately if HostInfoPosix::ComputeSharedLibraryDirectory return true and fall back to GetProgramFileSpec().GetDirectory().

source/Plugins/Platform/gdb-server/PlatformRemoteGDBServer.cpp

222 ↗

(On Diff #19615)

Do we need this condition only for remote debugging of Linux target? Or is it required for local LLGS debugging as well?
I'm wondering whether an alternative solution is appropriate - override HostInfoLinux::GetArchitecture(..) and put this condition in there. In this case it will be supported either with local or remote debugging, with and without LLGS.

source/Plugins/Process/Utility/RegisterContextLinux_i386.cpp

114–115

case llvm::Triple::x86:
case llvm::Triple::x86_64:

return g_register_infos_i386;

?

[ovyalov]

lgtm

[chaoren]

source/Plugins/Platform/gdb-server/PlatformRemoteGDBServer.cpp

222 ↗

(On Diff #19615)

I actually don't need this part for what I'm doing. Just in case I don't break anything without noticing, I'm going to remove this change.

include/lldb/Host/linux/HostInfoLinux.h

public:
 
     static bool GetOSVersion(uint32_t &major, uint32_t &minor, uint32_t &update);
     static bool GetOSBuildString(std::string &s);
     static bool GetOSKernelDescription(std::string &s);
     static llvm::StringRef GetDistributionId();
     static FileSpec GetProgramFileSpec();
 
   protected:
+    static bool ComputeSharedLibraryDirectory(FileSpec &file_spec);
     static bool ComputeSystemPluginsDirectory(FileSpec &file_spec);
     static bool ComputeUserPluginsDirectory(FileSpec &file_spec);
     static void ComputeHostArchitectureSupport(ArchSpec &arch_32, ArchSpec &arch_64);
 };
 }
 
 #endif

source/Host/linux/HostInfoLinux.cpp

if (!g_program_filespec)
             g_program_filespec.SetFile(exe_path, false);
         }
     }
 
     return g_program_filespec;
 }
 
 bool
+HostInfoLinux::ComputeSharedLibraryDirectory(FileSpec &file_spec)
+{
+    if (HostInfoPosix::ComputeSharedLibraryDirectory(file_spec))
+        return true;
+    file_spec.GetDirectory() = GetProgramFileSpec().GetDirectory();
+    return (bool)file_spec.GetDirectory();
+}
+
+bool
 HostInfoLinux::ComputeSystemPluginsDirectory(FileSpec &file_spec)
 {
     FileSpec temp_file("/usr/lib/lldb", true);
     file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
     return true;
 }
 
 bool

source/Plugins/Process/Utility/RegisterContextLinux_i386.cpp

RegisterContextLinux_i386::GetGPRSize() const
     return sizeof(GPR);
 }
 
 const RegisterInfo *
 RegisterContextLinux_i386::GetRegisterInfo() const
 {
     switch (m_target_arch.GetMachine())
     {
         case llvm::Triple::x86:            
+        case llvm::Triple::x86_64:
             return g_register_infos_i386;
         default:
             assert(false && "Unhandled target architecture.");
             return NULL;
     }
 }
 
 uint32_t