Remove shared pointer from NativeProcessProtocol

Summary:
The usage of shared_from_this forces us to separate construction and
initialization phases, because shared_from_this() is not available in
the constructor (or destructor). The shared semantics are not necessary,
as we always have a clear owner of the native process class
(GDBRemoteCommunicationServerLLDB object). Even if we need shared
semantics in the future (which I think we should strongly avoid),
reverting this will not be necessary -- the owners can still easily
store the native process object in a shared pointer if they really want
to -- this just prevents the knowledge of that from leaking into the
class implementation.

After this a NativeThread object will hold a reference to the parent
process (instead of a weak_ptr) -- having a process instance always
available allows us to simplify some logic in this class (some of it was
already simplified because we were asserting that the process is
available, but this makes it obvious).

Reviewers: krytarowski, eugene, zturner

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D35123

llvm-svn: 308282

1 files changed, 10 insertions, 14 deletions

diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index d988ee93a2bc..170d3b100064 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -214,7 +214,7 @@ static Status EnsureFDFlags(int fd, int flags) {
 // Public Static Methods
 // -----------------------------------------------------------------------------
 
-llvm::Expected<NativeProcessProtocolSP>
+llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
 NativeProcessLinux::Factory::Launch(ProcessLaunchInfo &launch_info,
                                     NativeDelegate &native_delegate,
                                     MainLoop &mainloop) const {
@@ -259,14 +259,13 @@ NativeProcessLinux::Factory::Launch(ProcessLaunchInfo &launch_info,
     return status.ToError();
   }
 
-  std::shared_ptr<NativeProcessLinux> process_sp(new NativeProcessLinux(
+  return std::unique_ptr<NativeProcessLinux>(new NativeProcessLinux(
       pid, launch_info.GetPTY().ReleaseMasterFileDescriptor(), native_delegate,
-      arch, mainloop));
-  process_sp->InitializeThreads({pid});
-  return process_sp;
+      arch, mainloop, {pid}));
 }
 
-llvm::Expected<NativeProcessProtocolSP> NativeProcessLinux::Factory::Attach(
+llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
+NativeProcessLinux::Factory::Attach(
     lldb::pid_t pid, NativeProcessProtocol::NativeDelegate &native_delegate,
     MainLoop &mainloop) const {
   Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
@@ -282,10 +281,8 @@ llvm::Expected<NativeProcessProtocolSP> NativeProcessLinux::Factory::Attach(
   if (!tids_or)
     return tids_or.takeError();
 
-  std::shared_ptr<NativeProcessLinux> process_sp(
-      new NativeProcessLinux(pid, -1, native_delegate, arch, mainloop));
-  process_sp->InitializeThreads(*tids_or);
-  return process_sp;
+  return std::unique_ptr<NativeProcessLinux>(new NativeProcessLinux(
+      pid, -1, native_delegate, arch, mainloop, *tids_or));
 }
 
 // -----------------------------------------------------------------------------
@@ -294,7 +291,8 @@ llvm::Expected<NativeProcessProtocolSP> NativeProcessLinux::Factory::Attach(
 
 NativeProcessLinux::NativeProcessLinux(::pid_t pid, int terminal_fd,
                                        NativeDelegate &delegate,
-                                       const ArchSpec &arch, MainLoop &mainloop)
+                                       const ArchSpec &arch, MainLoop &mainloop,
+                                       llvm::ArrayRef<::pid_t> tids)
     : NativeProcessProtocol(pid, terminal_fd, delegate), m_arch(arch) {
   if (m_terminal_fd != -1) {
     Status status = EnsureFDFlags(m_terminal_fd, O_NONBLOCK);
@@ -305,9 +303,7 @@ NativeProcessLinux::NativeProcessLinux(::pid_t pid, int terminal_fd,
   m_sigchld_handle = mainloop.RegisterSignal(
       SIGCHLD, [this](MainLoopBase &) { SigchldHandler(); }, status);
   assert(m_sigchld_handle && status.Success());
-}
 
-void NativeProcessLinux::InitializeThreads(llvm::ArrayRef<::pid_t> tids) {
   for (const auto &tid : tids) {
     NativeThreadLinuxSP thread_sp = AddThread(tid);
     assert(thread_sp && "AddThread() returned a nullptr thread");
@@ -2009,7 +2005,7 @@ NativeThreadLinuxSP NativeProcessLinux::AddThread(lldb::tid_t thread_id) {
   if (m_threads.empty())
     SetCurrentThreadID(thread_id);
 
-  auto thread_sp = std::make_shared<NativeThreadLinux>(this, thread_id);
+  auto thread_sp = std::make_shared<NativeThreadLinux>(*this, thread_id);
   m_threads.push_back(thread_sp);
 
   if (m_pt_proces_trace_id != LLDB_INVALID_UID) {