gdbserver: change 'all_processes' and 'all_threads' list type

This patch replaces the 'std::list' type of 'all_processes' and
'all_threads' with the more lightweight 'owning_intrusive_list'
type.

Approved-By: Simon Marchi <simon.marchi@efficios.com>

4 files changed, 39 insertions, 69 deletions

diff --git a/gdbserver/gdbthread.h b/gdbserver/gdbthread.h
index 0f81a0f68b5..d8840c0da99 100644
--- a/gdbserver/gdbthread.h
+++ b/gdbserver/gdbthread.h
@@ -20,14 +20,12 @@
 #define GDBSERVER_GDBTHREAD_H
 
 #include "gdbsupport/function-view.h"
-#include "inferiors.h"
-
-#include <list>
+#include "gdbsupport/owning_intrusive_list.h"
 
 struct btrace_target_info;
 struct regcache;
 
-struct thread_info
+struct thread_info : public intrusive_list_node<thread_info>
 {
   thread_info (ptid_t id, void *target_data)
     : id (id), target_data (target_data)
@@ -85,7 +83,7 @@ struct thread_info
   gdb_thread_options thread_options = 0;
 };
 
-extern std::list<thread_info *> all_threads;
+extern owning_intrusive_list<thread_info> all_threads;
 
 void remove_thread (struct thread_info *thread);
 struct thread_info *add_thread (ptid_t ptid, void *target_data);
diff --git a/gdbserver/inferiors.cc b/gdbserver/inferiors.cc
index 4245cb8fd9d..3a910e5e583 100644
--- a/gdbserver/inferiors.cc
+++ b/gdbserver/inferiors.cc
@@ -20,11 +20,12 @@
 
 #include "gdbsupport/common-gdbthread.h"
 #include "gdbsupport/common-inferior.h"
+#include "gdbsupport/owning_intrusive_list.h"
 #include "gdbthread.h"
 #include "dll.h"
 
-std::list<process_info *> all_processes;
-std::list<thread_info *> all_threads;
+owning_intrusive_list<process_info> all_processes;
+owning_intrusive_list<thread_info> all_threads;
 
 /* The current process.  */
 static process_info *current_process_;
@@ -41,14 +42,12 @@ static std::string current_inferior_cwd;
 struct thread_info *
 add_thread (ptid_t thread_id, void *target_data)
 {
-  thread_info *new_thread = new thread_info (thread_id, target_data);
-
-  all_threads.push_back (new_thread);
+  auto &new_thread = all_threads.emplace_back (thread_id, target_data);
 
   if (current_thread == NULL)
-    switch_to_thread (new_thread);
+    switch_to_thread (&new_thread);
 
-  return new_thread;
+  return &new_thread;
 }
 
 /* See gdbthread.h.  */
@@ -57,7 +56,7 @@ struct thread_info *
 get_first_thread (void)
 {
   if (!all_threads.empty ())
-    return all_threads.front ();
+    return &all_threads.front ();
   else
     return NULL;
 }
@@ -89,12 +88,6 @@ find_any_thread_of_pid (int pid)
   });
 }
 
-static void
-free_one_thread (thread_info *thread)
-{
-  delete thread;
-}
-
 void
 remove_thread (struct thread_info *thread)
 {
@@ -102,10 +95,10 @@ remove_thread (struct thread_info *thread)
     target_disable_btrace (thread->btrace);
 
   discard_queued_stop_replies (ptid_of (thread));
-  all_threads.remove (thread);
   if (current_thread == thread)
     switch_to_thread (nullptr);
-  free_one_thread (thread);
+
+  all_threads.erase (all_threads.iterator_to (*thread));
 }
 
 void *
@@ -129,7 +122,6 @@ set_thread_regcache_data (struct thread_info *thread, struct regcache *data)
 void
 clear_inferiors (void)
 {
-  for_each_thread (free_one_thread);
   all_threads.clear ();
 
   clear_dlls ();
@@ -141,11 +133,7 @@ clear_inferiors (void)
 struct process_info *
 add_process (int pid, int attached)
 {
-  process_info *process = new process_info (pid, attached);
-
-  all_processes.push_back (process);
-
-  return process;
+  return &all_processes.emplace_back (pid, attached);
 }
 
 /* Remove a process from the common process list and free the memory
@@ -158,10 +146,10 @@ remove_process (struct process_info *process)
   clear_symbol_cache (&process->symbol_cache);
   free_all_breakpoints (process);
   gdb_assert (find_thread_process (process) == NULL);
-  all_processes.remove (process);
   if (current_process () == process)
     switch_to_process (nullptr);
-  delete process;
+
+  all_processes.erase (all_processes.iterator_to (*process));
 }
 
 process_info *
@@ -178,7 +166,7 @@ process_info *
 get_first_process (void)
 {
   if (!all_processes.empty ())
-    return all_processes.front ();
+    return &all_processes.front ();
   else
     return NULL;
 }
@@ -221,13 +209,14 @@ current_process (void)
 void
 for_each_process (gdb::function_view<void (process_info *)> func)
 {
-  std::list<process_info *>::iterator next, cur = all_processes.begin ();
+  owning_intrusive_list<process_info>::iterator next, cur
+    = all_processes.begin ();
 
   while (cur != all_processes.end ())
     {
       next = cur;
       next++;
-      func (*cur);
+      func (&*cur);
       cur = next;
     }
 }
@@ -237,18 +226,9 @@ for_each_process (gdb::function_view<void (process_info *)> func)
 process_info *
 find_process (gdb::function_view<bool (process_info *)> func)
 {
-  std::list<process_info *>::iterator next, cur = all_processes.begin ();
-
-  while (cur != all_processes.end ())
-    {
-      next = cur;
-      next++;
-
-      if (func (*cur))
-	return *cur;
-
-      cur = next;
-    }
+  for (process_info &process : all_processes)
+    if (func (&process))
+      return &process;
 
   return NULL;
 }
@@ -258,18 +238,9 @@ find_process (gdb::function_view<bool (process_info *)> func)
 thread_info *
 find_thread (gdb::function_view<bool (thread_info *)> func)
 {
-  std::list<thread_info *>::iterator next, cur = all_threads.begin ();
-
-  while (cur != all_threads.end ())
-    {
-      next = cur;
-      next++;
-
-      if (func (*cur))
-	return *cur;
-
-      cur = next;
-    }
+  for (thread_info &thread : all_threads)
+    if (func (&thread))
+      return &thread;
 
   return NULL;
 }
@@ -300,13 +271,13 @@ find_thread (ptid_t filter, gdb::function_view<bool (thread_info *)> func)
 void
 for_each_thread (gdb::function_view<void (thread_info *)> func)
 {
-  std::list<thread_info *>::iterator next, cur = all_threads.begin ();
+  owning_intrusive_list<thread_info>::iterator next, cur = all_threads.begin ();
 
   while (cur != all_threads.end ())
     {
       next = cur;
       next++;
-      func (*cur);
+      func (&*cur);
       cur = next;
     }
 }
diff --git a/gdbserver/inferiors.h b/gdbserver/inferiors.h
index 7d453260270..3f2c5c70a39 100644
--- a/gdbserver/inferiors.h
+++ b/gdbserver/inferiors.h
@@ -20,8 +20,9 @@
 #define GDBSERVER_INFERIORS_H
 
 #include "gdbsupport/gdb_vecs.h"
+#include "gdbsupport/owning_intrusive_list.h"
+
 #include "dll.h"
-#include <list>
 
 struct thread_info;
 struct regcache;
@@ -32,7 +33,7 @@ struct raw_breakpoint;
 struct fast_tracepoint_jump;
 struct process_info_private;
 
-struct process_info
+struct process_info : public intrusive_list_node<process_info>
 {
   process_info (int pid_, int attached_)
   : pid (pid_), attached (attached_)
@@ -99,7 +100,7 @@ pid_of (const process_info *proc)
 struct process_info *current_process (void);
 struct process_info *get_thread_process (const struct thread_info *);
 
-extern std::list<process_info *> all_processes;
+extern owning_intrusive_list<process_info> all_processes;
 
 /* Invoke FUNC for each process.  */
 
diff --git a/gdbserver/server.cc b/gdbserver/server.cc
index 5190df4aed5..5058428f58b 100644
--- a/gdbserver/server.cc
+++ b/gdbserver/server.cc
@@ -1355,15 +1355,15 @@ handle_detach (char *own_buf)
      another process might delete the next thread in the iteration, which is
      the one saved by the safe iterator.  We will never delete the currently
      iterated on thread, so standard iteration should be safe.  */
-  for (thread_info *thread : all_threads)
+  for (thread_info &thread : all_threads)
     {
       /* Only threads that are of the process we are detaching.  */
-      if (thread->id.pid () != pid)
+      if (thread.id.pid () != pid)
 	continue;
 
       /* Only threads that have a pending fork event.  */
       target_waitkind kind;
-      thread_info *child = target_thread_pending_child (thread, &kind);
+      thread_info *child = target_thread_pending_child (&thread, &kind);
       if (child == nullptr || kind == TARGET_WAITKIND_THREAD_CLONED)
 	continue;
 
@@ -1375,7 +1375,7 @@ handle_detach (char *own_buf)
       if (detach_inferior (fork_child_process) != 0)
 	warning (_("Failed to detach fork child %s, child of %s"),
 		 target_pid_to_str (ptid_t (fork_child_pid)).c_str (),
-		 target_pid_to_str (thread->id).c_str ());
+		 target_pid_to_str (thread.id).c_str ());
     }
 
   if (detach_inferior (process) != 0)
@@ -2523,7 +2523,7 @@ static void
 handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
 {
   client_state &cs = get_client_state ();
-  static std::list<thread_info *>::const_iterator thread_iter;
+  static owning_intrusive_list<thread_info>::iterator thread_iter;
 
   /* Reply the current thread id.  */
   if (strcmp ("qC", own_buf) == 0 && !disable_packet_qC)
@@ -2536,7 +2536,7 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       else
 	{
 	  thread_iter = all_threads.begin ();
-	  ptid = (*thread_iter)->id;
+	  ptid = thread_iter->id;
 	}
 
       sprintf (own_buf, "QC");
@@ -2599,7 +2599,7 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
 	  thread_iter = all_threads.begin ();
 
 	  *own_buf++ = 'm';
-	  ptid_t ptid = (*thread_iter)->id;
+	  ptid_t ptid = thread_iter->id;
 	  write_ptid (own_buf, ptid);
 	  thread_iter++;
 	  return;
@@ -2611,7 +2611,7 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
 	  if (thread_iter != all_threads.end ())
 	    {
 	      *own_buf++ = 'm';
-	      ptid_t ptid = (*thread_iter)->id;
+	      ptid_t ptid = thread_iter->id;
 	      write_ptid (own_buf, ptid);
 	      thread_iter++;
 	      return;