Patch from Jay Cornwall that modifies the LLDB "Host" layer to reuse more
code between linux, darwin and BSD.



git-svn-id: https://llvm.org/svn/llvm-project/llvdb/trunk@113263 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/source/Host/common/Host.cpp b/source/Host/common/Host.cpp
new file mode 100644
index 0000000..00ba846
--- /dev/null
+++ b/source/Host/common/Host.cpp
@@ -0,0 +1,729 @@
+//===-- Host.cpp ------------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/Host.h"
+#include "lldb/Core/ArchSpec.h"
+#include "lldb/Core/ConstString.h"
+#include "lldb/Core/Error.h"
+#include "lldb/Core/FileSpec.h"
+#include "lldb/Core/Log.h"
+#include "lldb/Core/StreamString.h"
+#include "lldb/Host/Mutex.h"
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <sys/sysctl.h>
+#include <sys/wait.h>
+
+#if defined (__APPLE__)
+#include <libproc.h>
+#include <mach-o/dyld.h>
+#endif
+
+using namespace lldb;
+using namespace lldb_private;
+
+struct MonitorInfo
+{
+    lldb::pid_t pid;                            // The process ID to monitor
+    Host::MonitorChildProcessCallback callback; // The callback function to call when "pid" exits or signals
+    void *callback_baton;                       // The callback baton for the callback function
+    bool monitor_signals;                       // If true, call the callback when "pid" gets signaled.
+};
+
+static void *
+MonitorChildProcessThreadFunction (void *arg);
+
+lldb::thread_t
+Host::StartMonitoringChildProcess
+(
+    Host::MonitorChildProcessCallback callback,
+    void *callback_baton,
+    lldb::pid_t pid,
+    bool monitor_signals
+)
+{
+    lldb::thread_t thread = LLDB_INVALID_HOST_THREAD;
+    if (callback)
+    {
+        std::auto_ptr<MonitorInfo> info_ap(new MonitorInfo);
+            
+        info_ap->pid = pid;
+        info_ap->callback = callback;
+        info_ap->callback_baton = callback_baton;
+        info_ap->monitor_signals = monitor_signals;
+        
+        char thread_name[256];
+        ::snprintf (thread_name, sizeof(thread_name), "<lldb.host.wait4(pid=%i)>", pid);
+        thread = ThreadCreate (thread_name,
+                               MonitorChildProcessThreadFunction,
+                               info_ap.get(),
+                               NULL);
+                               
+        if (thread != LLDB_INVALID_HOST_THREAD)
+            info_ap.release();
+    }
+    return thread;
+}
+
+//------------------------------------------------------------------
+// Scoped class that will disable thread canceling when it is
+// constructed, and exception safely restore the previous value it
+// when it goes out of scope.
+//------------------------------------------------------------------
+class ScopedPThreadCancelDisabler
+{
+public:
+    ScopedPThreadCancelDisabler()
+    {
+        // Disable the ability for this thread to be cancelled
+        int err = ::pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &m_old_state);
+        if (err != 0)
+            m_old_state = -1;
+
+    }
+
+    ~ScopedPThreadCancelDisabler()
+    {
+        // Restore the ability for this thread to be cancelled to what it
+        // previously was.
+        if (m_old_state != -1)
+            ::pthread_setcancelstate (m_old_state, 0);
+    }
+private:
+    int m_old_state;    // Save the old cancelability state.
+};
+
+static void *
+MonitorChildProcessThreadFunction (void *arg)
+{
+    Log *log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_PROCESS);
+    const char *function = __FUNCTION__;
+    if (log)
+        log->Printf ("%s (arg = %p) thread starting...", function, arg);
+
+    MonitorInfo *info = (MonitorInfo *)arg;
+
+    const Host::MonitorChildProcessCallback callback = info->callback;
+    void * const callback_baton = info->callback_baton;
+    const lldb::pid_t pid = info->pid;
+    const bool monitor_signals = info->monitor_signals;
+
+    delete info;
+
+    int status = -1;
+    const int options = 0;
+    struct rusage *rusage = NULL;
+    while (1)
+    {
+        if (log)
+            log->Printf("%s ::wait4 (pid = %i, &status, options = %i, rusage = %p)...", function, pid, options, rusage);
+
+        // Wait for all child processes
+        ::pthread_testcancel ();
+        const lldb::pid_t wait_pid = ::wait4 (pid, &status, options, rusage);
+        ::pthread_testcancel ();
+
+        if (wait_pid == -1)
+        {
+            if (errno == EINTR)
+                continue;
+            else
+                break;
+        }
+        else if (wait_pid == pid)
+        {
+            bool exited = false;
+            int signal = 0;
+            int exit_status = 0;
+            const char *status_cstr = NULL;
+            if (WIFSTOPPED(status))
+            {
+                signal = WSTOPSIG(status);
+                status_cstr = "STOPPED";
+            }
+            else if (WIFEXITED(status))
+            {
+                exit_status = WEXITSTATUS(status);
+                status_cstr = "EXITED";
+                exited = true;
+            }
+            else if (WIFSIGNALED(status))
+            {
+                signal = WTERMSIG(status);
+                status_cstr = "SIGNALED";
+                exited = true;
+                exit_status = -1;
+            }
+            else
+            {
+                status_cstr = "(???)";
+            }
+
+            // Scope for pthread_cancel_disabler
+            {
+                ScopedPThreadCancelDisabler pthread_cancel_disabler;
+
+                if (log)
+                    log->Printf ("%s ::wait4 (pid = %i, &status, options = %i, rusage = %p) => pid = %i, status = 0x%8.8x (%s), signal = %i, exit_state = %i",
+                                 function,
+                                 wait_pid,
+                                 options,
+                                 rusage,
+                                 pid,
+                                 status,
+                                 status_cstr,
+                                 signal,
+                                 exit_status);
+
+                if (exited || (signal != 0 && monitor_signals))
+                {
+                    bool callback_return = callback (callback_baton, pid, signal, exit_status);
+                    
+                    // If our process exited, then this thread should exit
+                    if (exited)
+                        break;
+                    // If the callback returns true, it means this process should
+                    // exit
+                    if (callback_return)
+                        break;
+                }
+            }
+        }
+    }
+
+    if (log)
+        log->Printf ("%s (arg = %p) thread exiting...", __FUNCTION__, arg);
+
+    return NULL;
+}
+
+size_t
+Host::GetPageSize()
+{
+    return ::getpagesize();
+}
+
+//------------------------------------------------------------------
+// Returns true if the host system is Big Endian.
+//------------------------------------------------------------------
+ByteOrder
+Host::GetByteOrder ()
+{
+    union EndianTest
+    {
+        uint32_t num;
+        uint8_t  bytes[sizeof(uint32_t)];
+    } endian = { (uint16_t)0x11223344 };
+    switch (endian.bytes[0])
+    {
+        case 0x11: return eByteOrderLittle;
+        case 0x44: return eByteOrderBig;
+        case 0x33: return eByteOrderPDP;
+    }
+    return eByteOrderInvalid;
+}
+
+const ArchSpec &
+Host::GetArchitecture ()
+{
+    static ArchSpec g_host_arch;
+    if (!g_host_arch.IsValid())
+    {
+#if defined (__APPLE__)
+        uint32_t cputype, cpusubtype;
+        uint32_t is_64_bit_capable;
+        size_t len = sizeof(cputype);
+        if  (::sysctlbyname("hw.cputype", &cputype, &len, NULL, 0) == 0)
+        {
+            len = sizeof(cpusubtype);
+            if (::sysctlbyname("hw.cpusubtype", &cpusubtype, &len, NULL, 0) == 0)
+                g_host_arch.SetArch(cputype, cpusubtype);
+            
+            len = sizeof (is_64_bit_capable);
+            if  (::sysctlbyname("hw.cpu64bit_capable", &is_64_bit_capable, &len, NULL, 0) == 0)
+            {
+                if (is_64_bit_capable)
+                {
+                    if (cputype == CPU_TYPE_I386 && cpusubtype == CPU_SUBTYPE_486)
+                        cpusubtype = CPU_SUBTYPE_I386_ALL;
+
+                    cputype |= CPU_ARCH_ABI64;
+                }
+            }
+        }
+#elif defined (__linux__)
+        g_host_arch.SetArch(7u, 144u);
+#endif
+    }
+    return g_host_arch;
+}
+
+const ConstString &
+Host::GetVendorString()
+{
+    static ConstString g_vendor;
+    if (!g_vendor)
+    {
+#if defined (__APPLE__)
+        char ostype[64];
+        size_t len = sizeof(ostype);
+        if (::sysctlbyname("kern.ostype", &ostype, &len, NULL, 0) == 0)
+            g_vendor.SetCString (ostype);
+        else
+            g_vendor.SetCString("apple");
+#elif defined (__linux__)
+        g_vendor.SetCString("gnu");
+#endif
+    }
+    return g_vendor;
+}
+
+const ConstString &
+Host::GetOSString()
+{
+    static ConstString g_os_string;
+    if (!g_os_string)
+    {
+#if defined (__APPLE__)
+        g_os_string.SetCString("darwin");
+#elif defined (__linux__)
+        g_os_string.SetCString("linux");
+#endif
+    }
+    return g_os_string;
+}
+
+const ConstString &
+Host::GetTargetTriple()
+{
+    static ConstString g_host_triple;
+    if (!(g_host_triple))
+    {
+        StreamString triple;
+        triple.Printf("%s-%s-%s", 
+                      GetArchitecture().AsCString(),
+                      GetVendorString().AsCString(),
+                      GetOSString().AsCString());
+
+        std::transform (triple.GetString().begin(), 
+                        triple.GetString().end(), 
+                        triple.GetString().begin(), 
+                        ::tolower);
+
+        g_host_triple.SetCString(triple.GetString().c_str());
+    }
+    return g_host_triple;
+}
+
+lldb::pid_t
+Host::GetCurrentProcessID()
+{
+    return ::getpid();
+}
+
+lldb::tid_t
+Host::GetCurrentThreadID()
+{
+#if defined (__APPLE__)
+    return ::mach_thread_self();
+#else
+    return lldb::tid_t(pthread_self());
+#endif
+}
+
+const char *
+Host::GetSignalAsCString (int signo)
+{
+    switch (signo)
+    {
+    case SIGHUP:    return "SIGHUP";    // 1    hangup
+    case SIGINT:    return "SIGINT";    // 2    interrupt
+    case SIGQUIT:   return "SIGQUIT";   // 3    quit
+    case SIGILL:    return "SIGILL";    // 4    illegal instruction (not reset when caught)
+    case SIGTRAP:   return "SIGTRAP";   // 5    trace trap (not reset when caught)
+    case SIGABRT:   return "SIGABRT";   // 6    abort()
+#if  defined(_POSIX_C_SOURCE)
+    case SIGPOLL:   return "SIGPOLL";   // 7    pollable event ([XSR] generated, not supported)
+#else    // !_POSIX_C_SOURCE
+    case SIGEMT:    return "SIGEMT";    // 7    EMT instruction
+#endif    // !_POSIX_C_SOURCE
+    case SIGFPE:    return "SIGFPE";    // 8    floating point exception
+    case SIGKILL:   return "SIGKILL";   // 9    kill (cannot be caught or ignored)
+    case SIGBUS:    return "SIGBUS";    // 10    bus error
+    case SIGSEGV:   return "SIGSEGV";   // 11    segmentation violation
+    case SIGSYS:    return "SIGSYS";    // 12    bad argument to system call
+    case SIGPIPE:   return "SIGPIPE";   // 13    write on a pipe with no one to read it
+    case SIGALRM:   return "SIGALRM";   // 14    alarm clock
+    case SIGTERM:   return "SIGTERM";   // 15    software termination signal from kill
+    case SIGURG:    return "SIGURG";    // 16    urgent condition on IO channel
+    case SIGSTOP:   return "SIGSTOP";   // 17    sendable stop signal not from tty
+    case SIGTSTP:   return "SIGTSTP";   // 18    stop signal from tty
+    case SIGCONT:   return "SIGCONT";   // 19    continue a stopped process
+    case SIGCHLD:   return "SIGCHLD";   // 20    to parent on child stop or exit
+    case SIGTTIN:   return "SIGTTIN";   // 21    to readers pgrp upon background tty read
+    case SIGTTOU:   return "SIGTTOU";   // 22    like TTIN for output if (tp->t_local&LTOSTOP)
+#if  !defined(_POSIX_C_SOURCE)
+    case SIGIO:     return "SIGIO";     // 23    input/output possible signal
+#endif
+    case SIGXCPU:   return "SIGXCPU";   // 24    exceeded CPU time limit
+    case SIGXFSZ:   return "SIGXFSZ";   // 25    exceeded file size limit
+    case SIGVTALRM: return "SIGVTALRM"; // 26    virtual time alarm
+    case SIGPROF:   return "SIGPROF";   // 27    profiling time alarm
+#if  !defined(_POSIX_C_SOURCE)
+    case SIGWINCH:  return "SIGWINCH";  // 28    window size changes
+    case SIGINFO:   return "SIGINFO";   // 29    information request
+#endif
+    case SIGUSR1:   return "SIGUSR1";   // 30    user defined signal 1
+    case SIGUSR2:   return "SIGUSR2";   // 31    user defined signal 2
+    default:
+        break;
+    }
+    return NULL;
+}
+
+void
+Host::WillTerminate ()
+{
+}
+
+#if !defined (__APPLE__) // see macosx/Host.mm
+void
+Host::ThreadCreated (const char *thread_name)
+{
+}
+#endif
+
+struct HostThreadCreateInfo
+{
+    std::string thread_name;
+    thread_func_t thread_fptr;
+    thread_arg_t thread_arg;
+    
+    HostThreadCreateInfo (const char *name, thread_func_t fptr, thread_arg_t arg) :
+        thread_name (name ? name : ""),
+        thread_fptr (fptr),
+        thread_arg (arg)
+    {
+    }
+};
+
+static thread_result_t
+ThreadCreateTrampoline (thread_arg_t arg)
+{
+    HostThreadCreateInfo *info = (HostThreadCreateInfo *)arg;
+    Host::ThreadCreated (info->thread_name.c_str());
+    thread_func_t thread_fptr = info->thread_fptr;
+    thread_arg_t thread_arg = info->thread_arg;
+    
+    Log * log = lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_THREAD);
+    if (log)
+        log->Printf("thread created");
+    
+    delete info;
+    return thread_fptr (thread_arg);
+}
+
+lldb::thread_t
+Host::ThreadCreate
+(
+    const char *thread_name,
+    thread_func_t thread_fptr,
+    thread_arg_t thread_arg,
+    Error *error
+)
+{
+    lldb::thread_t thread = LLDB_INVALID_HOST_THREAD;
+    
+    // Host::ThreadCreateTrampoline will delete this pointer for us.
+    HostThreadCreateInfo *info_ptr = new HostThreadCreateInfo (thread_name, thread_fptr, thread_arg);
+    
+    int err = ::pthread_create (&thread, NULL, ThreadCreateTrampoline, info_ptr);
+    if (err == 0)
+    {
+        if (error)
+            error->Clear();
+        return thread;
+    }
+    
+    if (error)
+        error->SetError (err, eErrorTypePOSIX);
+    
+    return LLDB_INVALID_HOST_THREAD;
+}
+
+bool
+Host::ThreadCancel (lldb::thread_t thread, Error *error)
+{
+    int err = ::pthread_cancel (thread);
+    if (error)
+        error->SetError(err, eErrorTypePOSIX);
+    return err == 0;
+}
+
+bool
+Host::ThreadDetach (lldb::thread_t thread, Error *error)
+{
+    int err = ::pthread_detach (thread);
+    if (error)
+        error->SetError(err, eErrorTypePOSIX);
+    return err == 0;
+}
+
+bool
+Host::ThreadJoin (lldb::thread_t thread, thread_result_t *thread_result_ptr, Error *error)
+{
+    int err = ::pthread_join (thread, thread_result_ptr);
+    if (error)
+        error->SetError(err, eErrorTypePOSIX);
+    return err == 0;
+}
+
+//------------------------------------------------------------------
+// Control access to a static file thread name map using a single
+// static function to avoid a static constructor.
+//------------------------------------------------------------------
+static const char *
+ThreadNameAccessor (bool get, lldb::pid_t pid, lldb::tid_t tid, const char *name)
+{
+    uint64_t pid_tid = ((uint64_t)pid << 32) | (uint64_t)tid;
+
+    static pthread_mutex_t g_mutex = PTHREAD_MUTEX_INITIALIZER;
+    Mutex::Locker locker(&g_mutex);
+
+    typedef std::map<uint64_t, std::string> thread_name_map;
+    // rdar://problem/8153284
+    // Fixed a crasher where during shutdown, loggings attempted to access the
+    // thread name but the static map instance had already been destructed.
+    // Another approach is to introduce a static guard object which monitors its
+    // own destruction and raises a flag, but this incurs more overhead.
+    static thread_name_map *g_thread_names_ptr = new thread_name_map();
+    thread_name_map &g_thread_names = *g_thread_names_ptr;
+
+    if (get)
+    {
+        // See if the thread name exists in our thread name pool
+        thread_name_map::iterator pos = g_thread_names.find(pid_tid);
+        if (pos != g_thread_names.end())
+            return pos->second.c_str();
+    }
+    else
+    {
+        // Set the thread name
+        g_thread_names[pid_tid] = name;
+    }
+    return NULL;
+}
+
+const char *
+Host::GetThreadName (lldb::pid_t pid, lldb::tid_t tid)
+{
+    const char *name = ThreadNameAccessor (true, pid, tid, NULL);
+    if (name == NULL)
+    {
+#if defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED > MAC_OS_X_VERSION_10_5
+        // We currently can only get the name of a thread in the current process.
+        if (pid == Host::GetCurrentProcessID())
+        {
+            char pthread_name[1024];
+            if (::pthread_getname_np (::pthread_from_mach_thread_np (tid), pthread_name, sizeof(pthread_name)) == 0)
+            {
+                if (pthread_name[0])
+                {
+                    // Set the thread in our string pool
+                    ThreadNameAccessor (false, pid, tid, pthread_name);
+                    // Get our copy of the thread name string
+                    name = ThreadNameAccessor (true, pid, tid, NULL);
+                }
+            }
+        }
+#endif
+    }
+    return name;
+}
+
+void
+Host::SetThreadName (lldb::pid_t pid, lldb::tid_t tid, const char *name)
+{
+    lldb::pid_t curr_pid = Host::GetCurrentProcessID();
+    lldb::tid_t curr_tid = Host::GetCurrentThreadID();
+    if (pid == LLDB_INVALID_PROCESS_ID)
+        pid = curr_pid;
+
+    if (tid == LLDB_INVALID_THREAD_ID)
+        tid = curr_tid;
+
+#if defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED > MAC_OS_X_VERSION_10_5
+    // Set the pthread name if possible
+    if (pid == curr_pid && tid == curr_tid)
+    {
+        ::pthread_setname_np (name);
+    }
+#endif
+    ThreadNameAccessor (false, pid, tid, name);
+}
+
+FileSpec
+Host::GetProgramFileSpec ()
+{
+    static FileSpec g_program_filespec;
+    if (!g_program_filespec)
+    {
+#if defined (__APPLE__)
+        char program_fullpath[PATH_MAX];
+        // If DST is NULL, then return the number of bytes needed.
+        uint32_t len = sizeof(program_fullpath);
+        int err = _NSGetExecutablePath (program_fullpath, &len);
+        if (err == 0)
+            g_program_filespec.SetFile (program_fullpath);
+        else if (err == -1)
+        {
+            char *large_program_fullpath = (char *)::malloc (len + 1);
+
+            err = _NSGetExecutablePath (large_program_fullpath, &len);
+            if (err == 0)
+                g_program_filespec.SetFile (large_program_fullpath);
+
+            ::free (large_program_fullpath);
+        }
+#elif defined (__linux__)
+        char exe_path[PATH_MAX];
+        ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path));
+        if (len >= 0)
+            g_program_filespec = FileSpec(exe_path);
+#elif defined (__FreeBSD__)
+        int exe_path_mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, getpid() };
+        size_t exe_path_size;
+        if (sysctl(exe_path_mib, 4, NULL, &exe_path_size, NULL, 0) == 0)
+        {
+          char *exe_path = new char[exe_path_size];
+          if (sysctl(exe_path_mib, 4, exe_path, &exe_path_size, NULL, 0) == 0)
+              g_program_filespec = FileSpec(exe_path);
+        }
+#endif
+    }
+    return g_program_filespec;
+}
+
+FileSpec
+Host::GetModuleFileSpecForHostAddress (const void *host_addr)
+{
+    FileSpec module_filespec;
+    Dl_info info;
+    if (::dladdr (host_addr, &info))
+    {
+        if (info.dli_fname)
+            module_filespec.SetFile(info.dli_fname);
+    }
+    return module_filespec;
+}
+
+#if !defined (__APPLE__) // see Host.mm
+bool
+Host::ResolveExecutableInBundle (FileSpec *file)
+{
+  return false;
+}
+#endif
+
+uint32_t
+Host::ListProcessesMatchingName (const char *name, StringList &matches, std::vector<lldb::pid_t> &pids)
+{
+    uint32_t num_matches = 0;
+
+#if defined (__APPLE__)
+    int num_pids;
+    int size_of_pids;
+    int *pid_list;
+    
+    size_of_pids = proc_listpids(PROC_ALL_PIDS, 0, NULL, 0);
+    if (size_of_pids == -1)
+        return 0;
+        
+    num_pids = size_of_pids/sizeof(int);
+    pid_list = (int *) malloc(size_of_pids);
+    size_of_pids = proc_listpids(PROC_ALL_PIDS, 0, pid_list, size_of_pids);
+    if (size_of_pids == -1)
+        return 0;
+        
+    lldb::pid_t our_pid = getpid();
+    
+    for (int i = 0; i < num_pids; i++)
+    {
+        struct proc_bsdinfo bsd_info;
+        int error = proc_pidinfo (pid_list[i], PROC_PIDTBSDINFO, (uint64_t) 0, &bsd_info, PROC_PIDTBSDINFO_SIZE);
+        if (error == 0)
+            continue;
+        
+        // Don't offer to attach to zombie processes, already traced or exiting
+        // processes, and of course, ourselves...  It looks like passing the second arg of
+        // 0 to proc_listpids will exclude zombies anyway, but that's not documented so...
+        if (((bsd_info.pbi_flags & (PROC_FLAG_TRACED | PROC_FLAG_INEXIT)) != 0)
+             || (bsd_info.pbi_status == SZOMB)
+             || (bsd_info.pbi_pid == our_pid))
+             continue;
+        char pid_name[MAXCOMLEN * 2 + 1];
+        int name_len;
+        name_len = proc_name(bsd_info.pbi_pid, pid_name, MAXCOMLEN * 2);
+        if (name_len == 0)
+            continue;
+        
+        if (strstr(pid_name, name) != pid_name)
+            continue;
+        matches.AppendString (pid_name);
+        pids.push_back (bsd_info.pbi_pid);
+        num_matches++;        
+    }
+#endif
+    
+    return num_matches;
+}
+
+ArchSpec
+Host::GetArchSpecForExistingProcess (lldb::pid_t pid)
+{
+    ArchSpec return_spec;
+
+#if defined (__APPLE__)
+    struct proc_bsdinfo bsd_info;
+    int error = proc_pidinfo (pid, PROC_PIDTBSDINFO, (uint64_t) 0, &bsd_info, PROC_PIDTBSDINFO_SIZE);
+    if (error == 0)
+        return return_spec;
+    if (bsd_info.pbi_flags & PROC_FLAG_LP64)
+        return_spec.SetArch(LLDB_ARCH_DEFAULT_64BIT);
+    else 
+        return_spec.SetArch(LLDB_ARCH_DEFAULT_32BIT);
+#endif
+        
+    return return_spec;
+}
+
+ArchSpec
+Host::GetArchSpecForExistingProcess (const char *process_name)
+{
+    ArchSpec returnSpec;
+    StringList matches;
+    std::vector<lldb::pid_t> pids;
+    if (ListProcessesMatchingName(process_name, matches, pids))
+    {
+        if (matches.GetSize() == 1)
+        {
+            return GetArchSpecForExistingProcess(pids[0]);
+        }
+    }
+    return returnSpec;
+}
+
+#if !defined (__APPLE__) // see macosx/Host.mm
+bool
+Host::OpenFileInExternalEditor (FileSpec &file_spec, uint32_t line_no)
+{
+    return false;
+}
+#endif