[PATCH 00/11] Remove some usages of find_inferior

[PATCH 00/11] Remove some usages of find_inferior

[Simon Marchi]

This is a random sampling of removals of find_inferior, replacing them with the
new-ish find_thread/for_each_thread.

Simon Marchi (11):
  Remove usage of find_inferior in win32-i386-low.c
  Remove usage of find_inferior in win32-low.c
  Remove usages of find_inferior in linux-arm-low.c
  Remove usage of find_inferior in reset_lwp_ptrace_options_callback
  Remove usage of find_inferior in iterate_over_lwps
  Remove usage of find_inferior in unsuspend_all_lwps
  Remove usage of find_inferior in linux_stabilize_threads
  Remove usage of find_inferior when calling linux_set_resume_request
  Remove usage of find_thread when calling resume_status_pending_p
  Remove usages of find_thread when calling need_step_over_p
  Remove usage of find_inferior when calling kill_one_lwp_callback

 gdb/gdbserver/gdbthread.h      |  12 ++
 gdb/gdbserver/linux-arm-low.c  |  55 +++++----
 gdb/gdbserver/linux-low.c      | 248 ++++++++++++++---------------------------
 gdb/gdbserver/win32-i386-low.c |  29 ++---
 gdb/gdbserver/win32-low.c      |  12 +-
 5 files changed, 137 insertions(+), 219 deletions(-)

-- 
2.7.4

[PATCH 04/11] Remove usage of find_inferior in reset_lwp_ptrace_options_callback

[Simon Marchi]

Replace with for_each_thread, and inline code from
reset_lwp_ptrace_options_callback.

gdb/gdbserver/ChangeLog:

	* linux-low.c (reset_lwp_ptrace_options_callback): Remove.
	(linux_handle_new_gdb_connection): Use for_each_thread, inline
	code from reset_lwp_ptrace_options_callback.
---
 gdb/gdbserver/linux-low.c | 50 +++++++++++++++++++----------------------------
 1 file changed, 20 insertions(+), 30 deletions(-)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index b267c70..628135a 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -6434,33 +6434,6 @@ linux_supports_exec_events (void)
   return linux_supports_traceexec ();
 }
 
-/* Callback for 'find_inferior'.  Set the (possibly changed) ptrace
-   options for the specified lwp.  */
-
-static int
-reset_lwp_ptrace_options_callback (thread_info *thread, void *args)
-{
-  struct lwp_info *lwp = get_thread_lwp (thread);
-
-  if (!lwp->stopped)
-    {
-      /* Stop the lwp so we can modify its ptrace options.  */
-      lwp->must_set_ptrace_flags = 1;
-      linux_stop_lwp (lwp);
-    }
-  else
-    {
-      /* Already stopped; go ahead and set the ptrace options.  */
-      struct process_info *proc = find_process_pid (pid_of (thread));
-      int options = linux_low_ptrace_options (proc->attached);
-
-      linux_enable_event_reporting (lwpid_of (thread), options);
-      lwp->must_set_ptrace_flags = 0;
-    }
-
-  return 0;
-}
-
 /* Target hook for 'handle_new_gdb_connection'.  Causes a reset of the
    ptrace flags for all inferiors.  This is in case the new GDB connection
    doesn't support the same set of events that the previous one did.  */
@@ -6468,10 +6441,27 @@ reset_lwp_ptrace_options_callback (thread_info *thread, void *args)
 static void
 linux_handle_new_gdb_connection (void)
 {
-  pid_t pid;
-
   /* Request that all the lwps reset their ptrace options.  */
-  find_inferior (&all_threads, reset_lwp_ptrace_options_callback , &pid);
+  for_each_thread ([] (thread_info *thread)
+    {
+      struct lwp_info *lwp = get_thread_lwp (thread);
+
+      if (!lwp->stopped)
+	{
+	  /* Stop the lwp so we can modify its ptrace options.  */
+	  lwp->must_set_ptrace_flags = 1;
+	  linux_stop_lwp (lwp);
+	}
+      else
+	{
+	  /* Already stopped; go ahead and set the ptrace options.  */
+	  struct process_info *proc = find_process_pid (pid_of (thread));
+	  int options = linux_low_ptrace_options (proc->attached);
+
+	  linux_enable_event_reporting (lwpid_of (thread), options);
+	  lwp->must_set_ptrace_flags = 0;
+	}
+    });
 }
 
 static int
-- 
2.7.4

[PATCH 08/11] Remove usage of find_inferior when calling linux_set_resume_request

[Simon Marchi]

Replace it with for_each_thread.

gdb/gdbserver/ChangeLog:

	* linux-low.c (struct thread_resume_array): Remove.
	(linux_set_resume_request): Return void, take arguments
	directly.
	(linux_resume): Use for_each_thread.
---
 gdb/gdbserver/linux-low.c | 41 +++++++++++++++--------------------------
 1 file changed, 15 insertions(+), 26 deletions(-)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index b4c716c..c1d17f1 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -4569,33 +4569,22 @@ linux_resume_one_lwp (struct lwp_info *lwp,
   END_CATCH
 }
 
-struct thread_resume_array
-{
-  struct thread_resume *resume;
-  size_t n;
-};
-
-/* This function is called once per thread via find_inferior.
-   ARG is a pointer to a thread_resume_array struct.
-   We look up the thread specified by ENTRY in ARG, and mark the thread
-   with a pointer to the appropriate resume request.
+/* This function is called once per thread via for_each_thread.
+   We look up which resume request applies to THREAD and mark it with a
+   pointer to the appropriate resume request.
 
    This algorithm is O(threads * resume elements), but resume elements
    is small (and will remain small at least until GDB supports thread
    suspension).  */
 
-static int
-linux_set_resume_request (thread_info *thread, void *arg)
+static void
+linux_set_resume_request (thread_info *thread, thread_resume *resume, size_t n)
 {
   struct lwp_info *lwp = get_thread_lwp (thread);
-  int ndx;
-  struct thread_resume_array *r;
-
-  r = (struct thread_resume_array *) arg;
 
-  for (ndx = 0; ndx < r->n; ndx++)
+  for (int ndx = 0; ndx < n; ndx++)
     {
-      ptid_t ptid = r->resume[ndx].thread;
+      ptid_t ptid = resume[ndx].thread;
       if (ptid_equal (ptid, minus_one_ptid)
 	  || ptid == thread->id
 	  /* Handle both 'pPID' and 'pPID.-1' as meaning 'all threads
@@ -4604,7 +4593,7 @@ linux_set_resume_request (thread_info *thread, void *arg)
 	      && (ptid_is_pid (ptid)
 		  || ptid_get_lwp (ptid) == -1)))
 	{
-	  if (r->resume[ndx].kind == resume_stop
+	  if (resume[ndx].kind == resume_stop
 	      && thread->last_resume_kind == resume_stop)
 	    {
 	      if (debug_threads)
@@ -4620,7 +4609,7 @@ linux_set_resume_request (thread_info *thread, void *arg)
 
 	  /* Ignore (wildcard) resume requests for already-resumed
 	     threads.  */
-	  if (r->resume[ndx].kind != resume_stop
+	  if (resume[ndx].kind != resume_stop
 	      && thread->last_resume_kind != resume_stop)
 	    {
 	      if (debug_threads)
@@ -4662,7 +4651,7 @@ linux_set_resume_request (thread_info *thread, void *arg)
 	      continue;
 	    }
 
-	  lwp->resume = &r->resume[ndx];
+	  lwp->resume = &resume[ndx];
 	  thread->last_resume_kind = lwp->resume->kind;
 
 	  lwp->step_range_start = lwp->resume->step_range_start;
@@ -4684,14 +4673,12 @@ linux_set_resume_request (thread_info *thread, void *arg)
 			      lwpid_of (thread));
 	    }
 
-	  return 0;
+	  return;
 	}
     }
 
   /* No resume action for this thread.  */
   lwp->resume = NULL;
-
-  return 0;
 }
 
 /* find_inferior callback for linux_resume.
@@ -5104,7 +5091,6 @@ linux_resume_one_thread (thread_info *thread, void *arg)
 static void
 linux_resume (struct thread_resume *resume_info, size_t n)
 {
-  struct thread_resume_array array = { resume_info, n };
   struct thread_info *need_step_over = NULL;
   int any_pending;
   int leave_all_stopped;
@@ -5115,7 +5101,10 @@ linux_resume (struct thread_resume *resume_info, size_t n)
       debug_printf ("linux_resume:\n");
     }
 
-  find_inferior (&all_threads, linux_set_resume_request, &array);
+  for_each_thread ([&] (thread_info *thread)
+    {
+      linux_set_resume_request (thread, resume_info, n);
+    });
 
   /* If there is a thread which would otherwise be resumed, which has
      a pending status, then don't resume any threads - we can just
-- 
2.7.4

[PATCH 06/11] Remove usage of find_inferior in unsuspend_all_lwps

[Simon Marchi]

Replace with for_each_thread.  I inlined unsuspend_one_lwp in
unsuspend_all_lwps, since it is very simple.

gdb/gdbserver/ChangeLog:

	* linux-low.c (unsuspend_one_lwp): Remove.
	(unsuspend_all_lwps): Use for_each_thread, inline code from
	unsuspend_one_lwp.
---
 gdb/gdbserver/linux-low.c | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index fd8e45e..fce3fd0 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -2969,28 +2969,19 @@ select_event_lwp (struct lwp_info **orig_lp)
     }
 }
 
-/* Decrement the suspend count of an LWP.  */
-
-static int
-unsuspend_one_lwp (thread_info *thread, void *except)
-{
-  struct lwp_info *lwp = get_thread_lwp (thread);
-
-  /* Ignore EXCEPT.  */
-  if (lwp == except)
-    return 0;
-
-  lwp_suspended_decr (lwp);
-  return 0;
-}
-
 /* Decrement the suspend count of all LWPs, except EXCEPT, if non
    NULL.  */
 
 static void
 unsuspend_all_lwps (struct lwp_info *except)
 {
-  find_inferior (&all_threads, unsuspend_one_lwp, except);
+  for_each_thread ([&] (thread_info *thread)
+    {
+      lwp_info *lwp = get_thread_lwp (thread);
+
+      if (lwp != except)
+	lwp_suspended_decr (lwp);
+    });
 }
 
 static void move_out_of_jump_pad_callback (thread_info *thread);
-- 
2.7.4

[PATCH 07/11] Remove usage of find_inferior in linux_stabilize_threads

[Simon Marchi]

Simply replace with find_thread.

gdb/gdbserver/ChangeLog:

	* linux-low.c (stuck_in_jump_pad_callback): Change prototype,
	return bool, remove data argument.
	(linux_stabilize_threads): Use find_thread.
---
 gdb/gdbserver/linux-low.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index fce3fd0..b4c716c 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -2985,7 +2985,7 @@ unsuspend_all_lwps (struct lwp_info *except)
 }
 
 static void move_out_of_jump_pad_callback (thread_info *thread);
-static int stuck_in_jump_pad_callback (thread_info *thread, void *data);
+static bool stuck_in_jump_pad_callback (thread_info *thread);
 static int lwp_running (thread_info *thread, void *data);
 static ptid_t linux_wait_1 (ptid_t ptid,
 			    struct target_waitstatus *ourstatus,
@@ -3024,13 +3024,8 @@ static ptid_t linux_wait_1 (ptid_t ptid,
 static void
 linux_stabilize_threads (void)
 {
-  struct thread_info *saved_thread;
-  struct thread_info *thread_stuck;
+  thread_info *thread_stuck = find_thread (stuck_in_jump_pad_callback);
 
-  thread_stuck
-    = (struct thread_info *) find_inferior (&all_threads,
-					    stuck_in_jump_pad_callback,
-					    NULL);
   if (thread_stuck != NULL)
     {
       if (debug_threads)
@@ -3039,7 +3034,7 @@ linux_stabilize_threads (void)
       return;
     }
 
-  saved_thread = current_thread;
+  thread_info *saved_thread = current_thread;
 
   stabilizing_threads = 1;
 
@@ -3082,10 +3077,8 @@ linux_stabilize_threads (void)
 
   if (debug_threads)
     {
-      thread_stuck
-	= (struct thread_info *) find_inferior (&all_threads,
-						stuck_in_jump_pad_callback,
-						NULL);
+      thread_stuck = find_thread (stuck_in_jump_pad_callback);
+
       if (thread_stuck != NULL)
 	debug_printf ("couldn't stabilize, LWP %ld got stuck in jump pad\n",
 		      lwpid_of (thread_stuck));
@@ -4111,13 +4104,13 @@ wait_for_sigstop (void)
     }
 }
 
-/* Returns true if LWP ENTRY is stopped in a jump pad, and we can't
+/* Returns true if THREAD is stopped in a jump pad, and we can't
    move it out, because we need to report the stop event to GDB.  For
    example, if the user puts a breakpoint in the jump pad, it's
    because she wants to debug it.  */
 
-static int
-stuck_in_jump_pad_callback (thread_info *thread, void *data)
+static bool
+stuck_in_jump_pad_callback (thread_info *thread)
 {
   struct lwp_info *lwp = get_thread_lwp (thread);
 
-- 
2.7.4

[PATCH 11/11] Remove usage of find_inferior when calling kill_one_lwp_callback

[Simon Marchi]

Replace with for_each_thread.

gdb/gdbserver/ChangeLog:

	* linux-low.c (kill_one_lwp_callback): Return void, take
	argument directly, don't filter on pid.
	(linux_kill): Use for_each_thread.
---
 gdb/gdbserver/linux-low.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 33eb4f8..274263a 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -1356,17 +1356,13 @@ kill_wait_lwp (struct lwp_info *lwp)
     perror_with_name ("kill_wait_lwp");
 }
 
-/* Callback for `find_inferior'.  Kills an lwp of a given process,
+/* Callback for `for_each_thread'.  Kills an lwp of a given process,
    except the leader.  */
 
-static int
-kill_one_lwp_callback (thread_info *thread, void *args)
+static void
+kill_one_lwp_callback (thread_info *thread, int pid)
 {
   struct lwp_info *lwp = get_thread_lwp (thread);
-  int pid = * (int *) args;
-
-  if (thread->id.pid () != pid)
-    return 0;
 
   /* We avoid killing the first thread here, because of a Linux kernel (at
      least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before
@@ -1378,11 +1374,10 @@ kill_one_lwp_callback (thread_info *thread, void *args)
       if (debug_threads)
 	debug_printf ("lkop: is last of process %s\n",
 		      target_pid_to_str (thread->id));
-      return 0;
+      return;
     }
 
   kill_wait_lwp (lwp);
-  return 0;
 }
 
 static int
@@ -1399,7 +1394,10 @@ linux_kill (int pid)
      first, as PTRACE_KILL will not work otherwise.  */
   stop_all_lwps (0, NULL);
 
-  find_inferior (&all_threads, kill_one_lwp_callback , &pid);
+  for_each_thread (pid, [&] (thread_info *thread)
+    {
+      kill_one_lwp_callback (thread, pid);
+    });
 
   /* See the comment in linux_kill_one_lwp.  We did not kill the first
      thread in the list, so do so now.  */
-- 
2.7.4

[PATCH 01/11] Remove usage of find_inferior in win32-i386-low.c

[Simon Marchi]

Straightforward replacement of find_inferior with the overload of
for_each_thread that filters on pid.  I am able to build-test this
patch, but not run it.

gdb/gdbserver/ChangeLog:

	* win32-i386-low.c (update_debug_registers_callback): Rename
	to ...
	(update_debug_registers): ... this, return void, remove pid_p arg.
	(x86_dr_low_set_addr, x86_dr_low_set_control): Use for_each_thread.
---
 gdb/gdbserver/win32-i386-low.c | 29 +++++++++--------------------
 1 file changed, 9 insertions(+), 20 deletions(-)

diff --git a/gdb/gdbserver/win32-i386-low.c b/gdb/gdbserver/win32-i386-low.c
index fd99ca9..1961a98 100644
--- a/gdb/gdbserver/win32-i386-low.c
+++ b/gdb/gdbserver/win32-i386-low.c
@@ -36,21 +36,14 @@
 
 static struct x86_debug_reg_state debug_reg_state;
 
-static int
-update_debug_registers_callback (thread_info *thr, void *pid_p)
+static void
+update_debug_registers (thread_info *thread)
 {
-  win32_thread_info *th = (win32_thread_info *) thread_target_data (thr);
-  int pid = *(int *) pid_p;
-
-  /* Only update the threads of this process.  */
-  if (pid_of (thr) == pid)
-    {
-      /* The actual update is done later just before resuming the lwp,
-	 we just mark that the registers need updating.  */
-      th->debug_registers_changed = 1;
-    }
+  win32_thread_info *th = (win32_thread_info *) thread_target_data (thread);
 
-  return 0;
+  /* The actual update is done later just before resuming the lwp,
+     we just mark that the registers need updating.  */
+  th->debug_registers_changed = 1;
 }
 
 /* Update the inferior's debug register REGNUM from STATE.  */
@@ -58,12 +51,10 @@ update_debug_registers_callback (thread_info *thr, void *pid_p)
 static void
 x86_dr_low_set_addr (int regnum, CORE_ADDR addr)
 {
-  /* Only update the threads of this process.  */
-  int pid = pid_of (current_thread);
-
   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 
-  find_inferior (&all_threads, update_debug_registers_callback, &pid);
+  /* Only update the threads of this process.  */
+  for_each_thread (current_thread->id.pid (), update_debug_registers);
 }
 
 /* Update the inferior's DR7 debug control register from STATE.  */
@@ -72,9 +63,7 @@ static void
 x86_dr_low_set_control (unsigned long control)
 {
   /* Only update the threads of this process.  */
-  int pid = pid_of (current_thread);
-
-  find_inferior (&all_threads, update_debug_registers_callback, &pid);
+  for_each_thread (current_thread->id.pid (), update_debug_registers);
 }
 
 /* Return the current value of a DR register of the current thread's
-- 
2.7.4

[PATCH 09/11] Remove usage of find_thread when calling resume_status_pending_p

[Simon Marchi]

Replace with find_thread.  Instead of setting the flag in the callback,
make the callback return true/false, and check the result against NULL
in the caller.

gdb/gdbserver/ChangeLog:

	* linux-low.c (resume_status_pending_p): Return bool, remove
	flag_p argument.
	(linux_resume): Use find_thread.
---
 gdb/gdbserver/linux-low.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index c1d17f1..ed897e9 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -4684,20 +4684,17 @@ linux_set_resume_request (thread_info *thread, thread_resume *resume, size_t n)
 /* find_inferior callback for linux_resume.
    Set *FLAG_P if this lwp has an interesting status pending.  */
 
-static int
-resume_status_pending_p (thread_info *thread, void *flag_p)
+static bool
+resume_status_pending_p (thread_info *thread)
 {
   struct lwp_info *lwp = get_thread_lwp (thread);
 
   /* LWPs which will not be resumed are not interesting, because
      we might not wait for them next time through linux_wait.  */
   if (lwp->resume == NULL)
-    return 0;
+    return false;
 
-  if (thread_still_has_status_pending_p (thread))
-    * (int *) flag_p = 1;
-
-  return 0;
+  return thread_still_has_status_pending_p (thread);
 }
 
 /* Return 1 if this lwp that GDB wants running is stopped at an
@@ -5092,7 +5089,6 @@ static void
 linux_resume (struct thread_resume *resume_info, size_t n)
 {
   struct thread_info *need_step_over = NULL;
-  int any_pending;
   int leave_all_stopped;
 
   if (debug_threads)
@@ -5112,9 +5108,9 @@ linux_resume (struct thread_resume *resume_info, size_t n)
      would otherwise be sent.  In non-stop mode, we'll apply this
      logic to each thread individually.  We consume all pending events
      before considering to start a step-over (in all-stop).  */
-  any_pending = 0;
+  bool any_pending = false;
   if (!non_stop)
-    find_inferior (&all_threads, resume_status_pending_p, &any_pending);
+    any_pending = find_thread (resume_status_pending_p) != NULL;
 
   /* If there is a thread which would otherwise be resumed, which is
      stopped at a breakpoint that needs stepping over, then don't
-- 
2.7.4

[PATCH 10/11] Remove usages of find_thread when calling need_step_over_p

[Simon Marchi]

Replace with find_thread.

gdb/gdbserver/ChangeLog:

	* linux-low.c (need_step_over_p): Return bool, remove dummy
	argument.
	(linux_resume, proceed_all_lwps): Use find_thread.
---
 gdb/gdbserver/linux-low.c | 32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index ed897e9..33eb4f8 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -4702,8 +4702,8 @@ resume_status_pending_p (thread_info *thread)
    required STOP_PC adjustment has already been propagated to the
    inferior's regcache.  */
 
-static int
-need_step_over_p (thread_info *thread, void *dummy)
+static bool
+need_step_over_p (thread_info *thread)
 {
   struct lwp_info *lwp = get_thread_lwp (thread);
   struct thread_info *saved_thread;
@@ -4713,7 +4713,7 @@ need_step_over_p (thread_info *thread, void *dummy)
   /* GDBserver is skipping the extra traps from the wrapper program,
      don't have to do step over.  */
   if (proc->tdesc == NULL)
-    return 0;
+    return false;
 
   /* LWPs which will not be resumed are not interesting, because we
      might not wait for them next time through linux_wait.  */
@@ -4723,7 +4723,7 @@ need_step_over_p (thread_info *thread, void *dummy)
       if (debug_threads)
 	debug_printf ("Need step over [LWP %ld]? Ignoring, not stopped\n",
 		      lwpid_of (thread));
-      return 0;
+      return false;
     }
 
   if (thread->last_resume_kind == resume_stop)
@@ -4732,7 +4732,7 @@ need_step_over_p (thread_info *thread, void *dummy)
 	debug_printf ("Need step over [LWP %ld]? Ignoring, should remain"
 		      " stopped\n",
 		      lwpid_of (thread));
-      return 0;
+      return false;
     }
 
   gdb_assert (lwp->suspended >= 0);
@@ -4742,7 +4742,7 @@ need_step_over_p (thread_info *thread, void *dummy)
       if (debug_threads)
 	debug_printf ("Need step over [LWP %ld]? Ignoring, suspended\n",
 		      lwpid_of (thread));
-      return 0;
+      return false;
     }
 
   if (lwp->status_pending_p)
@@ -4751,7 +4751,7 @@ need_step_over_p (thread_info *thread, void *dummy)
 	debug_printf ("Need step over [LWP %ld]? Ignoring, has pending"
 		      " status.\n",
 		      lwpid_of (thread));
-      return 0;
+      return false;
     }
 
   /* Note: PC, not STOP_PC.  Either GDB has adjusted the PC already,
@@ -4770,7 +4770,7 @@ need_step_over_p (thread_info *thread, void *dummy)
 		      "Old stop_pc was 0x%s, PC is now 0x%s\n",
 		      lwpid_of (thread),
 		      paddress (lwp->stop_pc), paddress (pc));
-      return 0;
+      return false;
     }
 
   /* On software single step target, resume the inferior with signal
@@ -4784,7 +4784,7 @@ need_step_over_p (thread_info *thread, void *dummy)
 		      " signals.\n",
 		      lwpid_of (thread));
 
-      return 0;
+      return false;
     }
 
   saved_thread = current_thread;
@@ -4806,7 +4806,7 @@ need_step_over_p (thread_info *thread, void *dummy)
 			  lwpid_of (thread), paddress (pc));
 
 	  current_thread = saved_thread;
-	  return 0;
+	  return false;
 	}
       else
 	{
@@ -4819,7 +4819,7 @@ need_step_over_p (thread_info *thread, void *dummy)
 	     that find_inferior stops looking.  */
 	  current_thread = saved_thread;
 
-	  return 1;
+	  return true;
 	}
     }
 
@@ -4830,7 +4830,7 @@ need_step_over_p (thread_info *thread, void *dummy)
 		  " at 0x%s\n",
 		  lwpid_of (thread), paddress (pc));
 
-  return 0;
+  return false;
 }
 
 /* Start a step-over operation on LWP.  When LWP stopped at a
@@ -5119,9 +5119,7 @@ linux_resume (struct thread_resume *resume_info, size_t n)
      to queue any signals that would otherwise be delivered or
      queued.  */
   if (!any_pending && supports_breakpoints ())
-    need_step_over
-      = (struct thread_info *) find_inferior (&all_threads,
-					      need_step_over_p, NULL);
+    need_step_over = find_thread (need_step_over_p);
 
   leave_all_stopped = (need_step_over != NULL || any_pending);
 
@@ -5291,9 +5289,7 @@ proceed_all_lwps (void)
 
   if (supports_breakpoints ())
     {
-      need_step_over
-	= (struct thread_info *) find_inferior (&all_threads,
-						need_step_over_p, NULL);
+      need_step_over = find_thread (need_step_over_p);
 
       if (need_step_over != NULL)
 	{
-- 
2.7.4

[PATCH 02/11] Remove usage of find_inferior in win32-low.c

[Simon Marchi]

Replace with for_each_thread.

gdb/gdbserver/ChangeLog:

	* win32-low.c (continue_one_thread): Return void, take argument
	directly.
	(child_continue): Use for_each_thread.
---
 gdb/gdbserver/win32-low.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index 66fc52c..c7684b7 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -428,10 +428,9 @@ do_initial_child_stuff (HANDLE proch, DWORD pid, int attached)
 
 /* Resume all artificially suspended threads if we are continuing
    execution.  */
-static int
-continue_one_thread (thread_info *thread, void *id_ptr)
+static void
+continue_one_thread (thread_info *thread, int thread_id)
 {
-  int thread_id = * (int *) id_ptr;
   win32_thread_info *th = (win32_thread_info *) thread_target_data (thread);
 
   if (thread_id == -1 || thread_id == th->tid)
@@ -455,8 +454,6 @@ continue_one_thread (thread_info *thread, void *id_ptr)
 	  th->suspended = 0;
 	}
     }
-
-  return 0;
 }
 
 static BOOL
@@ -464,7 +461,10 @@ child_continue (DWORD continue_status, int thread_id)
 {
   /* The inferior will only continue after the ContinueDebugEvent
      call.  */
-  find_inferior (&all_threads, continue_one_thread, &thread_id);
+  for_each_thread ([&] (thread_info *thread)
+    {
+      continue_one_thread (thread, thread_id);
+    });
   faked_breakpoint = 0;
 
   if (!ContinueDebugEvent (current_event.dwProcessId,
-- 
2.7.4

[PATCH 05/11] Remove usage of find_inferior in iterate_over_lwps

[Simon Marchi]

Replace find_inferior with find_thread.  Since it may be useful in the
future, I added another overload to find_thread which filters based on a
ptid (using ptid_t::matches), so now iterate_over_lwps doesn't have to
do the filtering itself.  iterate_over_lwps_filter is removed and
inlined into iterate_over_lwps.

gdb/gdbserver/ChangeLog:

	* gdbthread.h (find_thread): Add overload with ptid_t filter.
	* linux-low.c (struct iterate_over_lwps_args): Remove.
	(iterate_over_lwps_filter): Remove.
	(iterate_over_lwps): Use find_thread.
---
 gdb/gdbserver/gdbthread.h | 12 ++++++++++++
 gdb/gdbserver/linux-low.c | 45 ++++++---------------------------------------
 2 files changed, 18 insertions(+), 39 deletions(-)

diff --git a/gdb/gdbserver/gdbthread.h b/gdb/gdbserver/gdbthread.h
index b82d5b0..df1e477 100644
--- a/gdb/gdbserver/gdbthread.h
+++ b/gdb/gdbserver/gdbthread.h
@@ -123,6 +123,18 @@ find_thread (int pid, Func func)
     });
 }
 
+/* Find the first thread that matches FILTER for which FUNC returns true.
+   Return NULL if no thread satisfying these conditions is found.  */
+
+template <typename Func>
+static thread_info *
+find_thread (ptid_t filter, Func func)
+{
+  return find_thread ([&] (thread_info *thread) {
+    return thread->id.matches (filter) && func (thread);
+  });
+}
+
 /* Invoke FUNC for each thread.  */
 
 template <typename Func>
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 628135a..fd8e45e 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -1876,42 +1876,6 @@ num_lwps (int pid)
   return count;
 }
 
-/* The arguments passed to iterate_over_lwps.  */
-
-struct iterate_over_lwps_args
-{
-  /* The FILTER argument passed to iterate_over_lwps.  */
-  ptid_t filter;
-
-  /* The CALLBACK argument passed to iterate_over_lwps.  */
-  iterate_over_lwps_ftype *callback;
-
-  /* The DATA argument passed to iterate_over_lwps.  */
-  void *data;
-};
-
-/* Callback for find_inferior used by iterate_over_lwps to filter
-   calls to the callback supplied to that function.  Returning a
-   nonzero value causes find_inferiors to stop iterating and return
-   the current inferior_list_entry.  Returning zero indicates that
-   find_inferiors should continue iterating.  */
-
-static int
-iterate_over_lwps_filter (thread_info *thread, void *args_p)
-{
-  struct iterate_over_lwps_args *args
-    = (struct iterate_over_lwps_args *) args_p;
-
-  if (thread->id.matches (args->filter))
-    {
-      struct lwp_info *lwp = get_thread_lwp (thread);
-
-      return (*args->callback) (lwp, args->data);
-    }
-
-  return 0;
-}
-
 /* See nat/linux-nat.h.  */
 
 struct lwp_info *
@@ -1919,10 +1883,13 @@ iterate_over_lwps (ptid_t filter,
 		   iterate_over_lwps_ftype callback,
 		   void *data)
 {
-  struct iterate_over_lwps_args args = {filter, callback, data};
+  thread_info *thread = find_thread (filter, [&] (thread_info *thread)
+    {
+      lwp_info *lwp = get_thread_lwp (thread);
+
+      return callback (lwp, data);
+    });
 
-  thread_info *thread = find_inferior (&all_threads, iterate_over_lwps_filter,
-				       &args);
   if (thread == NULL)
     return NULL;
 
-- 
2.7.4

[PATCH 03/11] Remove usages of find_inferior in linux-arm-low.c

[Simon Marchi]

Replace two usages with the overload of for_each_thread that filters on
pid.  It allows to simplify the callback a little bit.

gdb/gdbserver/ChangeLog:

	* linux-arm-low.c (struct update_registers_data): Remove.
	(update_registers_callback): Return void, take arguments
	directly, don't check thread's pid.
	(arm_insert_point, arm_remove_point): Use for_each_thread.
---
 gdb/gdbserver/linux-arm-low.c | 55 ++++++++++++++++++++-----------------------
 1 file changed, 26 insertions(+), 29 deletions(-)

diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index 3fddec6..f2c030d 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -460,35 +460,22 @@ arm_linux_hw_point_initialize (enum raw_bkpt_type raw_type, CORE_ADDR addr,
 /* Callback to mark a watch-/breakpoint to be updated in all threads of
    the current process.  */
 
-struct update_registers_data
-{
-  int watch;
-  int i;
-};
-
-static int
-update_registers_callback (thread_info *thread, void *arg)
+static void
+update_registers_callback (thread_info *thread, int watch, int i)
 {
   struct lwp_info *lwp = get_thread_lwp (thread);
-  struct update_registers_data *data = (struct update_registers_data *) arg;
-
-  /* Only update the threads of the current process.  */
-  if (pid_of (thread) == pid_of (current_thread))
-    {
-      /* The actual update is done later just before resuming the lwp,
-         we just mark that the registers need updating.  */
-      if (data->watch)
-	lwp->arch_private->wpts_changed[data->i] = 1;
-      else
-	lwp->arch_private->bpts_changed[data->i] = 1;
 
-      /* If the lwp isn't stopped, force it to momentarily pause, so
-         we can update its breakpoint registers.  */
-      if (!lwp->stopped)
-        linux_stop_lwp (lwp);
-    }
+  /* The actual update is done later just before resuming the lwp,
+     we just mark that the registers need updating.  */
+  if (watch)
+    lwp->arch_private->wpts_changed[i] = 1;
+  else
+    lwp->arch_private->bpts_changed[i] = 1;
 
-  return 0;
+  /* If the lwp isn't stopped, force it to momentarily pause, so
+     we can update its breakpoint registers.  */
+  if (!lwp->stopped)
+    linux_stop_lwp (lwp);
 }
 
 static int
@@ -538,9 +525,14 @@ arm_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
   for (i = 0; i < count; i++)
     if (!arm_hwbp_control_is_enabled (pts[i].control))
       {
-	struct update_registers_data data = { watch, i };
 	pts[i] = p;
-	find_inferior (&all_threads, update_registers_callback, &data);
+
+	/* Only update the threads of the current process.  */
+	for_each_thread (current_thread->id.pid (), [&] (thread_info *thread)
+	  {
+	    update_registers_callback (thread, watch, i);
+	  });
+
 	return 0;
       }
 
@@ -578,9 +570,14 @@ arm_remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
   for (i = 0; i < count; i++)
     if (arm_linux_hw_breakpoint_equal (&p, pts + i))
       {
-	struct update_registers_data data = { watch, i };
 	pts[i].control = arm_hwbp_control_disable (pts[i].control);
-	find_inferior (&all_threads, update_registers_callback, &data);
+
+	/* Only update the threads of the current process.  */
+	for_each_thread (current_thread->id.pid (), [&] (thread_info *thread)
+	  {
+	    update_registers_callback (thread, watch, i);
+	  });
+
 	return 0;
       }
 
-- 
2.7.4

Re: [PATCH 00/11] Remove some usages of find_inferior

[Sergio Durigan Junior]

On Friday, November 17 2017, Simon Marchi wrote:

> This is a random sampling of removals of find_inferior, replacing them with the
> new-ish find_thread/for_each_thread.

Thanks for the patch.  I looked over it, specifically the Linux-related
bits, and they seem fine.  Having hacked this code a bit on gdbserver
some time ago, I for one welcome this change.

> Simon Marchi (11):
>   Remove usage of find_inferior in win32-i386-low.c
>   Remove usage of find_inferior in win32-low.c
>   Remove usages of find_inferior in linux-arm-low.c
>   Remove usage of find_inferior in reset_lwp_ptrace_options_callback
>   Remove usage of find_inferior in iterate_over_lwps
>   Remove usage of find_inferior in unsuspend_all_lwps
>   Remove usage of find_inferior in linux_stabilize_threads
>   Remove usage of find_inferior when calling linux_set_resume_request
>   Remove usage of find_thread when calling resume_status_pending_p
>   Remove usages of find_thread when calling need_step_over_p
>   Remove usage of find_inferior when calling kill_one_lwp_callback
>
>  gdb/gdbserver/gdbthread.h      |  12 ++
>  gdb/gdbserver/linux-arm-low.c  |  55 +++++----
>  gdb/gdbserver/linux-low.c      | 248 ++++++++++++++---------------------------
>  gdb/gdbserver/win32-i386-low.c |  29 ++---
>  gdb/gdbserver/win32-low.c      |  12 +-
>  5 files changed, 137 insertions(+), 219 deletions(-)
>
> -- 
> 2.7.4

-- 
Sergio
GPG key ID: 237A 54B1 0287 28BF 00EF  31F4 D0EB 7628 65FC 5E36
Please send encrypted e-mail if possible
http://sergiodj.net/

Re: [PATCH 00/11] Remove some usages of find_inferior

[Simon Marchi]

On 2017-11-19 02:21 PM, Sergio Durigan Junior wrote:
> On Friday, November 17 2017, Simon Marchi wrote:
> 
>> This is a random sampling of removals of find_inferior, replacing them with the
>> new-ish find_thread/for_each_thread.
> 
> Thanks for the patch.  I looked over it, specifically the Linux-related
> bits, and they seem fine.  Having hacked this code a bit on gdbserver
> some time ago, I for one welcome this change.

Thanks a lot for looking at it!  I am pushing the series.

Simon