diff --git a/i/lldb/source/Host/macosx/objcxx/Host.mm b/lldb/source/Host/macosx/objcxx/Host.mm
--- a/i/lldb/source/Host/macosx/objcxx/Host.mm
+++ b/lldb/source/Host/macosx/objcxx/Host.mm
@@ -144,42 +144,22 @@
     ::memset(pid_str, 0, sizeof(pid_str));
     ConnectionStatus status;
     const size_t pid_str_len = file_conn.Read(
-        pid_str, sizeof(pid_str), std::chrono::seconds(0), status, NULL);
+        pid_str, sizeof(pid_str), std::chrono::seconds(5), status, NULL);
     if (pid_str_len > 0) {
       int pid = atoi(pid_str);
+
+      // The inferior sends its pid right before it calls posix_spawn.
+      // We want to wait a tiny bit for the next process to get 
+      // started, and stop at dyld_start, before we attach.
+      const int short_sleep = 100000; // 0.1 seconds
+      ::usleep(short_sleep);
+
       return (void *)(intptr_t)pid;
     }
   }
   return NULL;
 }
 
-static bool WaitForProcessToSIGSTOP(const lldb::pid_t pid,
-                                    const int timeout_in_seconds) {
-  const int time_delta_usecs = 100000;
-  const int num_retries = timeout_in_seconds / time_delta_usecs;
-  for (int i = 0; i < num_retries; i++) {
-    struct proc_bsdinfo bsd_info;
-    int error = ::proc_pidinfo(pid, PROC_PIDTBSDINFO, (uint64_t)0, &bsd_info,
-                               PROC_PIDTBSDINFO_SIZE);
-
-    switch (error) {
-    case EINVAL:
-    case ENOTSUP:
-    case ESRCH:
-    case EPERM:
-      return false;
-
-    default:
-      break;
-
-    case 0:
-      if (bsd_info.pbi_status == SSTOP)
-        return true;
-    }
-    ::usleep(time_delta_usecs);
-  }
-  return false;
-}
 #if !defined(__arm__) && !defined(__arm64__) && !defined(__aarch64__)
 
 const char *applscript_in_new_tty = "tell application \"Terminal\"\n"
@@ -323,15 +303,9 @@
 
   thread_result_t accept_thread_result = NULL;
   lldb_error = accept_thread->Join(&accept_thread_result);
-  if (lldb_error.Success() && accept_thread_result) {
+  if (lldb_error.Success() && accept_thread_result)
     pid = (intptr_t)accept_thread_result;
 
-    // Wait for process to be stopped at the entry point by watching
-    // for the process status to be set to SSTOP which indicates it it
-    // SIGSTOP'ed at the entry point
-    WaitForProcessToSIGSTOP(pid, 5);
-  }
-
   llvm::sys::fs::remove(unix_socket_name);
   [applescript release];
   if (pid != LLDB_INVALID_PROCESS_ID)
diff --git a/i/lldb/tools/darwin-debug/darwin-debug.cpp b/lldb/tools/darwin-debug/darwin-debug.cpp
--- a/i/lldb/tools/darwin-debug/darwin-debug.cpp
+++ b/lldb/tools/darwin-debug/darwin-debug.cpp
@@ -23,6 +23,7 @@
 
 #include <crt_externs.h>
 #include <getopt.h>
+#include <fcntl.h>
 #include <limits.h>
 #include <mach/machine.h>
 #include <signal.h>
@@ -30,6 +31,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/errno.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -97,7 +99,7 @@
 
 pid_t posix_spawn_for_debug(char *const *argv, char *const *envp,
                             const char *working_dir, cpu_type_t cpu_type,
-                            int disable_aslr) {
+                            int disable_aslr, int socket_fd) {
   pid_t pid = 0;
 
   const char *path = argv[0];
@@ -147,6 +149,29 @@
   if (working_dir)
     ::chdir(working_dir);
 
+  // We were able to connect to the socket, now write our PID so whomever
+  // launched us will know this process's ID
+  char pid_str[64];
+  const int pid_str_len =
+      ::snprintf(pid_str, sizeof(pid_str), "%i", ::getpid());
+  const int bytes_sent = ::send(socket_fd, pid_str, pid_str_len, 0);
+
+  if (pid_str_len != bytes_sent) {
+    perror("error: send (socket_fd, pid_str, pid_str_len, 0)");
+    exit(1);
+  }
+
+  // Set the socket socket_fd marked as close-on-exec, leave
+  // it open for now.  lldb might use this to detect when the
+  // exec has happened, and we can attach to the inferior
+  // safely.
+  errno = 0;
+  int opts = fcntl (socket_fd, F_GETFL);
+  if (errno == 0) {
+    opts = opts | O_CLOEXEC;
+    fcntl (socket_fd, F_SETFL, opts);
+  }
+
   exit_with_errno(::posix_spawnp(&pid, path, NULL, &attr, (char *const *)argv,
                                  (char *const *)envp),
                   "posix_spawn() error: ");
@@ -290,21 +315,6 @@
     exit(1);
   }
 
-  // We were able to connect to the socket, now write our PID so whomever
-  // launched us will know this process's ID
-  char pid_str[64];
-  const int pid_str_len =
-      ::snprintf(pid_str, sizeof(pid_str), "%i", ::getpid());
-  const int bytes_sent = ::send(s, pid_str, pid_str_len, 0);
-
-  if (pid_str_len != bytes_sent) {
-    perror("error: send (s, pid_str, pid_str_len, 0)");
-    exit(1);
-  }
-
-  // We are done with the socket
-  close(s);
-
   system("clear");
   printf("Launching: '%s'\n", argv[0]);
   if (working_dir.empty()) {
@@ -326,7 +336,8 @@
       pass_env ? *_NSGetEnviron() : NULL, // Pass current environment as we may
                                           // have modified it if "--env" options
                                           // was used, do NOT pass "envp" here
-      working_dir.empty() ? NULL : working_dir.c_str(), cpu_type, disable_aslr);
+      working_dir.empty() ? NULL : working_dir.c_str(), cpu_type, disable_aslr,
+      s);
 
   return 0;
 }