Handle fork in target application (#191)

* Always print PID in log messages

* omnitrace-dl updates

- omnitrace_preload does not call omnitrace_init or omnitrace_init_tooling
- omnitrace_preload will call omnitrace_set_mpi if OMNITRACE_USE_MPI
  or OMNITRACE_USE_MPIP in the env is true but not call it otherwise
  because doing so either overrides OMNITRACE_USE_PID (when true) or
  disable mpip from initialization (when false) and the MPI
  init can be caught later and override OMNITRACE_USE_PID

* config updates

- set_setting_value sets user update type
- remove volatile from get_settings_configured
- don't override settings::default_process_suffix
- don't kill process in omnitrace_exit_action
- set_state ignores updating state if >= State::Finalized

* Handle state > State::Finalized

* fork gotcha updates

- unsets LD_PRELOAD
- sets OMNITRACE_ROOT_PROCESS
- sets OMNITRACE_CHILD_PROCESS

* libomnitrace library.cpp updates

- basic_bundle for fini metrics
- handle finalization from child process

* sampling updates

- sampling::shutdown handles when child process

* Add example and test using fork

* Update run-ci script to support not submitting

* Tweak test envs

* Update build flags when codecov enabled

* remove unnecessary includes of sampling header

* Replace mpi copy/fini static lambda with free-funcs

* Update codecov job

* Fix OMPT segfaults after finalization

* Miscellaneous updates after rebase

* fixes for causal profiling

* revert some run-ci.sh changes

* Disable storing env in sampling::shutdown

* formatting fix

* Update timemory submodule

- fixed occasional synchronization issues with allocator offloading
- exclude protozero:: from internal samples

* improve root/child process detection

- avoid omnitrace_finalize in MPI when child process
- revert some testing tweaks

source/lib/omnitrace/library/thread_info.cpp

@@ -78,7 +78,7 @@ init_index_data(int64_t _tid, bool _offset = false)
         itr       = thread_index_data{};
         int _verb = 2;
         // if thread created using finalization, bump up the minimum verbosity level
-        if(get_state() == State::Finalized && _offset) _verb += 2;
+        if(get_state() >= State::Finalized && _offset) _verb += 2;
         if(!config::settings_are_configured())
         {
             OMNITRACE_BASIC_VERBOSE_F(
@@ -145,6 +145,12 @@ grow_data(int64_t _tid)
     return _max_threads;
 }
 
+bool
+thread_info::exists()
+{
+    return (get_info_data() != nullptr);
+}
+
 const std::optional<thread_info>&
 thread_info::init(bool _offset)
 {
@@ -177,6 +183,11 @@ thread_info::init(bool _offset)
 const std::optional<thread_info>&
 thread_info::get()
 {
+    if(!exists())
+    {
+        static thread_local auto _v = std::optional<thread_info>{};
+        return _v;
+    }
     return get_info_data(utility::get_thread_index());
 }