Change iterate_over_lwps to take a gdb::function_view

This changes iterate_over_lwps to use a gdb::function_view.  This was
needed in order to make null_ptid and minus_one_ptid 'const'.

gdb/ChangeLog
2019-03-12  Tom Tromey  <tromey@adacore.com>

	* linux-nat.c (iterate_over_lwps): Update.
	(stop_callback): Remove parameter.
	(stop_wait_callback, detach_callback, resume_set_callback)
	(select_singlestep_lwp_callback, set_ignore_sigint)
	(status_callback, resumed_callback, resume_clear_callback)
	(kill_callback, kill_wait_callback, linux_nat_stop_lwp): Remove
	data parameter.
	(linux_nat_target::detach, linux_nat_target::resume)
	(linux_stop_and_wait_all_lwps, select_event_lwp)
	(linux_nat_filter_event, linux_nat_wait_1)
	(linux_nat_target::kill, linux_nat_target::stop)
	(linux_nat_target::stop): Update.
	(linux_nat_resume_callback): Change type.
	(resume_stopped_resumed_lwps, count_events_callback)
	(select_event_lwp_callback): Likewise.
	(linux_stop_lwp, linux_nat_stop_lwp): Update.
	* arm-linux-nat.c (struct update_registers_data): Remove.
	(update_registers_callback): Change type.
	(arm_linux_insert_hw_breakpoint1): Update.
	* nat/x86-linux-dregs.c (update_debug_registers_callback): Remove
	parameter.
	(x86_linux_dr_set_addr): Update.
	(x86_linux_dr_set_control): Update.
	* nat/linux-nat.h (iterate_over_lwps_ftype): Remove parameter.
	(iterate_over_lwps): Use gdb::function_view.
	* nat/aarch64-linux-hw-point.c (struct
	aarch64_dr_update_callback_param): Remove.
	(debug_reg_change_callback): Change type.
	(aarch64_notify_debug_reg_change): Update.
	* s390-linux-nat.c (s390_refresh_per_info): Update.

gdb/gdbserver/ChangeLog
2019-03-12  Tom Tromey  <tromey@adacore.com>

	* linux-low.c (iterate_over_lwps): Update.

3 files changed, 17 insertions, 25 deletions

diff --git a/gdb/nat/aarch64-linux-hw-point.c b/gdb/nat/aarch64-linux-hw-point.c
index eed0606..1efec9a 100644
--- a/gdb/nat/aarch64-linux-hw-point.c
+++ b/gdb/nat/aarch64-linux-hw-point.c
@@ -278,27 +278,17 @@ aarch64_align_watchpoint (CORE_ADDR addr, int len, CORE_ADDR *aligned_addr_p,
     *next_addr_orig_p = align_down (*next_addr_orig_p + alignment, alignment);
 }
 
-struct aarch64_dr_update_callback_param
-{
-  int is_watchpoint;
-  unsigned int idx;
-};
-
-/* Callback for iterate_over_lwps.  Records the
+/* Helper for aarch64_notify_debug_reg_change.  Records the
    information about the change of one hardware breakpoint/watchpoint
    setting for the thread LWP.
-   The information is passed in via PTR.
    N.B.  The actual updating of hardware debug registers is not
    carried out until the moment the thread is resumed.  */
 
 static int
-debug_reg_change_callback (struct lwp_info *lwp, void *ptr)
+debug_reg_change_callback (struct lwp_info *lwp, int is_watchpoint,
+			   unsigned int idx)
 {
-  struct aarch64_dr_update_callback_param *param_p
-    = (struct aarch64_dr_update_callback_param *) ptr;
   int tid = ptid_of_lwp (lwp).lwp ();
-  int idx = param_p->idx;
-  int is_watchpoint = param_p->is_watchpoint;
   struct arch_lwp_info *info = lwp_arch_private_info (lwp);
   dr_changed_t *dr_changed_ptr;
   dr_changed_t dr_changed;
@@ -356,13 +346,14 @@ static void
 aarch64_notify_debug_reg_change (const struct aarch64_debug_reg_state *state,
 				 int is_watchpoint, unsigned int idx)
 {
-  struct aarch64_dr_update_callback_param param;
   ptid_t pid_ptid = ptid_t (current_lwp_ptid ().pid ());
 
-  param.is_watchpoint = is_watchpoint;
-  param.idx = idx;
-
-  iterate_over_lwps (pid_ptid, debug_reg_change_callback, (void *) &param);
+  iterate_over_lwps (pid_ptid, [=] (struct lwp_info *info)
+			       {
+				 return debug_reg_change_callback (info,
+								   is_watchpoint,
+								   idx);
+			       });
 }
 
 /* Reconfigure STATE to be compatible with Linux kernels with the PR
diff --git a/gdb/nat/linux-nat.h b/gdb/nat/linux-nat.h
index 1e32dd9..29f43d8 100644
--- a/gdb/nat/linux-nat.h
+++ b/gdb/nat/linux-nat.h
@@ -20,6 +20,7 @@
 #ifndef NAT_LINUX_NAT_H
 #define NAT_LINUX_NAT_H
 
+#include "common/function-view.h"
 #include "target/waitstatus.h"
 
 struct lwp_info;
@@ -43,7 +44,7 @@ struct arch_lwp_info;
 extern ptid_t current_lwp_ptid (void);
 
 /* Function type for the CALLBACK argument of iterate_over_lwps.  */
-typedef int (iterate_over_lwps_ftype) (struct lwp_info *lwp, void *arg);
+typedef int (iterate_over_lwps_ftype) (struct lwp_info *lwp);
 
 /* Iterate over all LWPs.  Calls CALLBACK with its second argument set
    to DATA for every LWP in the list.  If CALLBACK returns nonzero for
@@ -51,9 +52,9 @@ typedef int (iterate_over_lwps_ftype) (struct lwp_info *lwp, void *arg);
    LWP immediately.  Otherwise return NULL.  This function must be
    provided by the client.  */
 
-extern struct lwp_info *iterate_over_lwps (ptid_t filter,
-					   iterate_over_lwps_ftype callback,
-					   void *data);
+extern struct lwp_info *iterate_over_lwps
+    (ptid_t filter,
+     gdb::function_view<iterate_over_lwps_ftype> callback);
 
 /* Return the ptid of LWP.  */
 
diff --git a/gdb/nat/x86-linux-dregs.c b/gdb/nat/x86-linux-dregs.c
index 33bbfa2..29b4ee1 100644
--- a/gdb/nat/x86-linux-dregs.c
+++ b/gdb/nat/x86-linux-dregs.c
@@ -76,7 +76,7 @@ x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
    the actual debug registers immediately prior to LWP resuming.  */
 
 static int
-update_debug_registers_callback (struct lwp_info *lwp, void *arg)
+update_debug_registers_callback (struct lwp_info *lwp)
 {
   lwp_set_debug_registers_changed (lwp, 1);
 
@@ -106,7 +106,7 @@ x86_linux_dr_set_addr (int regnum, CORE_ADDR addr)
 
   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 
-  iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
+  iterate_over_lwps (pid_ptid, update_debug_registers_callback);
 }
 
 /* See nat/x86-linux-dregs.h.  */
@@ -124,7 +124,7 @@ x86_linux_dr_set_control (unsigned long control)
 {
   ptid_t pid_ptid = ptid_t (current_lwp_ptid ().pid ());
 
-  iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
+  iterate_over_lwps (pid_ptid, update_debug_registers_callback);
 }
 
 /* See nat/x86-linux-dregs.h.  */