Create private_thread_info hierarchy

There are multiple definitions of the private_thread_info structure
compiled in the same GDB build.  Because of the one definition rule, we
need to change this if we want to be able to make them non-POD (e.g. use
std::vector fields).  This patch creates a class hierarchy, with
private_thread_info being an abstract base class, and all the specific
implementations inheriting from it.

In order to poison XNEW/xfree for non-POD types, it is also needed to
get rid of the xfree in thread_info::~thread_info, which operates on an
opaque type.  This is replaced by thread_info::priv now being a
unique_ptr, which calls the destructor of the private_thread_info
subclass when the thread is being destroyed.

Including gdbthread.h from darwin-nat.h gave these errors:

/Users/simark/src/binutils-gdb/gdb/gdbthread.h:609:3: error: must use 'class' tag to refer to type 'thread_info' in this scope
  thread_info *m_thread;
  ^
  class
/usr/include/mach/thread_act.h:240:15: note: class 'thread_info' is hidden by a non-type declaration of 'thread_info' here
kern_return_t thread_info
              ^

It turns out that there is a thread_info function in the Darwin/XNU/mach API:

  http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_info.html

Therefore, I had to add the class keyword at a couple of places in gdbthread.h,
I don't really see a way around it.

gdb/ChangeLog:

	* gdbthread.h (private_thread_info): Define structure type, add
	virtual pure destructor.
	(thread_info) <priv>: Change type to unique_ptr.
	<private_dtor>: Remove.
	* thread.c (add_thread_with_info): Adjust to use of unique_ptr.
	(private_thread_info::~private_thread_info): Provide default
	implementation.
	(thread_info::~thread_info): Don't call private_dtor nor
	manually free priv.
	* aix-thread.c (private_thread_info): Rename to ...
	(aix_thread_info): ... this.
	(get_aix_thread_info): New.
	(sync_threadlists): Adjust.
	(iter_tid): Adjust.
	(aix_thread_resume): Adjust.
	(aix_thread_fetch_registers): Adjust.
	(aix_thread_store_registers): Adjust.
	(aix_thread_extra_thread_info): Adjust.
	* darwin-nat.h (private_thread_info): Rename to ...
	(darwin_thread_info): ... this.
	(get_darwin_thread_info): New.
	* darwin-nat.c (darwin_init_thread_list): Adjust.
	(darwin_check_new_threads): Adjust.
	(thread_info_from_private_thread_info): Adjust.
	* linux-thread-db.c (private_thread_info): Rename to ...
	(thread_db_thread_info): ... this, initialize fields.
	(get_thread_db_thread_info): New.
	<dying>: Change type to bool.
	(update_thread_state): Adjust to type rename.
	(record_thread): Adjust to type rename an use of unique_ptr.
	(thread_db_pid_to_str): Likewise.
	(thread_db_extra_thread_info): Likewise.
	(thread_db_thread_handle_to_thread_info): Likewise.
	(thread_db_get_thread_local_address): Likewise.
	* nto-tdep.h (private_thread_info): Rename to ...
	(nto_thread_info): ... this, initialize fields.
	(get_nto_thread_info): New.
	<name>: Change type to std::string.
	* nto-tdep.c (nto_extra_thread_info): Adjust to type rename and
	use of unique_ptr.
	* nto-procfs.c (update_thread_private_data_name): Adjust to
	std::string change, allocate nto_private_thread_info with new.
	(update_thread_private_data): Adjust to unique_ptr.
	* remote.c (private_thread_info): Rename to ...
	(remote_thread_info): ... this, initialize data members with
	default values.
	<extra, name>: Change type to std::string.
	<thread_handle>: Change type to non-pointer.
	(free_private_thread_info): Remove.
	(get_private_info_thread): Rename to...
	(get_remote_thread_info): ... this, change return type, adjust to
	use of unique_ptr, use remote_thread_info constructor.
	(remote_add_thread): Adjust.
	(get_private_info_ptid): Rename to...
	(get_remote_thread_info): ...this, change return type.
	(remote_thread_name): Use get_remote_thread_info, adjust to
	change to std::string.
	(struct thread_item) <~thread_item>: Remove.
	<thread_handle>: Make non pointer.
	(start_thread): Adjust to thread_item::thread_handle type
	change.
	(remote_update_thread_list): Adjust to type name change, move
	strings from temporary to long-lived object instead of
	duplicating.
	(remote_threads_extra_info): Use get_remote_thread_info.
	(process_initial_stop_replies): Likewise.
	(resume_clear_thread_private_info): Likewise.
	(remote_resume): Adjust to type name change.
	(remote_commit_resume): Use get_remote_thread_info.
	(process_stop_reply): Adjust to type name change.
	(remote_stopped_by_sw_breakpoint): Use get_remote_thread_info.
	(remote_stopped_by_hw_breakpoint): Likewise.
	(remote_stopped_by_watchpoint): Likewise.
	(remote_stopped_data_address): Likewise.
	(remote_core_of_thread): Likewise.
	(remote_thread_handle_to_thread_info): Use
	get_private_info_thread, adjust to thread_handle field type
	change.

1 files changed, 25 insertions, 21 deletions

diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c
index ea032fc..27f9ce8 100644
--- a/gdb/linux-thread-db.c
+++ b/gdb/linux-thread-db.c
@@ -251,16 +251,21 @@ delete_thread_db_info (int pid)
 /* Use "struct private_thread_info" to cache thread state.  This is
    a substantial optimization.  */
 
-struct private_thread_info
+struct thread_db_thread_info : public private_thread_info
 {
   /* Flag set when we see a TD_DEATH event for this thread.  */
-  unsigned int dying:1;
+  bool dying = false;
 
   /* Cached thread state.  */
-  td_thrhandle_t th;
-  thread_t tid;
+  td_thrhandle_t th {};
+  thread_t tid {};
 };
-
+
+static thread_db_thread_info *
+get_thread_db_thread_info (thread_info *thread)
+{
+  return static_cast<thread_db_thread_info *> (thread->priv.get ());
+}
 
 static const char *
 thread_db_err_str (td_err_e err)
@@ -1040,7 +1045,7 @@ thread_db_inferior_created (struct target_ops *target, int from_tty)
    from libthread_db thread state information.  */
 
 static void
-update_thread_state (struct private_thread_info *priv,
+update_thread_state (thread_db_thread_info *priv,
 		     const td_thrinfo_t *ti_p)
 {
   priv->dying = (ti_p->ti_state == TD_THR_UNKNOWN
@@ -1057,8 +1062,6 @@ record_thread (struct thread_db_info *info,
 	       ptid_t ptid, const td_thrhandle_t *th_p,
 	       const td_thrinfo_t *ti_p)
 {
-  struct private_thread_info *priv;
-
   /* A thread ID of zero may mean the thread library has not
      initialized yet.  Leave private == NULL until the thread library
      has initialized.  */
@@ -1066,7 +1069,7 @@ record_thread (struct thread_db_info *info,
     return tp;
 
   /* Construct the thread's private data.  */
-  priv = XCNEW (struct private_thread_info);
+  thread_db_thread_info *priv = new thread_db_thread_info;
 
   priv->th = *th_p;
   priv->tid = ti_p->ti_tid;
@@ -1078,7 +1081,7 @@ record_thread (struct thread_db_info *info,
   if (tp == NULL || tp->state == THREAD_EXITED)
     tp = add_thread_with_info (ptid, priv);
   else
-    tp->priv = priv;
+    tp->priv.reset (priv);
 
   if (target_has_execution)
     check_thread_signals ();
@@ -1381,11 +1384,10 @@ thread_db_pid_to_str (struct target_ops *ops, ptid_t ptid)
   if (thread_info != NULL && thread_info->priv != NULL)
     {
       static char buf[64];
-      thread_t tid;
+      thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
 
-      tid = thread_info->priv->tid;
       snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)",
-		(unsigned long) tid, ptid_get_lwp (ptid));
+		(unsigned long) priv->tid, ptid_get_lwp (ptid));
 
       return buf;
     }
@@ -1404,7 +1406,9 @@ thread_db_extra_thread_info (struct target_ops *self,
   if (info->priv == NULL)
     return NULL;
 
-  if (info->priv->dying)
+  thread_db_thread_info *priv = get_thread_db_thread_info (info);
+
+  if (priv->dying)
     return "Exiting";
 
   return NULL;
@@ -1434,7 +1438,9 @@ thread_db_thread_handle_to_thread_info (struct target_ops *ops,
 
   ALL_NON_EXITED_THREADS (tp)
     {
-      if (tp->inf == inf && tp->priv != NULL && handle_tid == tp->priv->tid)
+      thread_db_thread_info *priv = get_thread_db_thread_info (tp);
+
+      if (tp->inf == inf && priv != NULL && handle_tid == priv->tid)
         return tp;
     }
 
@@ -1464,9 +1470,8 @@ thread_db_get_thread_local_address (struct target_ops *ops,
     {
       td_err_e err;
       psaddr_t address;
-      struct thread_db_info *info;
-
-      info = get_thread_db_info (ptid_get_pid (ptid));
+      thread_db_info *info = get_thread_db_info (ptid_get_pid (ptid));
+      thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
 
       /* Finally, get the address of the variable.  */
       if (lm != 0)
@@ -1479,7 +1484,7 @@ thread_db_get_thread_local_address (struct target_ops *ops,
 	  /* Note the cast through uintptr_t: this interface only works if
 	     a target address fits in a psaddr_t, which is a host pointer.
 	     So a 32-bit debugger can not access 64-bit TLS through this.  */
-	  err = info->td_thr_tls_get_addr_p (&thread_info->priv->th,
+	  err = info->td_thr_tls_get_addr_p (&priv->th,
 					     (psaddr_t)(uintptr_t) lm,
 					     offset, &address);
 	}
@@ -1497,8 +1502,7 @@ thread_db_get_thread_local_address (struct target_ops *ops,
 	     PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
 	     The constant number 1 depends on GNU __libc_setup_tls
 	     initialization of l_tls_modid to 1.  */
-	  err = info->td_thr_tlsbase_p (&thread_info->priv->th,
-					1, &address);
+	  err = info->td_thr_tlsbase_p (&priv->th, 1, &address);
 	  address = (char *) address + offset;
 	}