Pass inferior down to target_detach and to_detach

The to_detach target_ops method implementations are currently expected
to work on current_inferior/inferior_ptid.  In order to make things more
explicit, and remove some "shadow" parameter passing through globals,
this patch adds an "inferior" parameter to to_detach.  Implementations
will be expected to use this instead of relying on the global.  However,
to keep things simple, this patch only does the minimum that is
necessary to add the parameter.  The following patch gives an example of
how one such implementation would be adapted.  If the approach is deemed
good, we can then look into adapting more implementations.  Until then,
they'll continue to work as they do currently.

gdb/ChangeLog:

	* target.h (struct target_ops) <to_detach>: Add inferior
	parameter.
	(target_detach): Likewise.
	* target.c (dispose_inferior): Pass inferior down.
	(target_detach): Pass inferior down.  Assert that it is equal to
	the current inferior.
	* aix-thread.c (aix_thread_detach): Pass inferior down.
	* corefile.c (core_file_command): Pass current_inferior() down.
	* corelow.c (core_detach): Add inferior parameter.
	* darwin-nat.c (darwin_detach): Likewise.
	* gnu-nat.c (gnu_detach): Likewise.
	* inf-ptrace.c (inf_ptrace_detach): Likewise.
	* infcmd.c (detach_command): Pass current_inferior() down to
	target_detach.
	* infrun.c (follow_fork_inferior): Pass parent_inf to
	target_detach.
	(handle_vfork_child_exec_or_exit): Pass inf->vfork_parent to
	target_detach.
	* linux-nat.c (linux_nat_detach): Add inferior parameter.
	* linux-thread-db.c (thread_db_detach): Likewise.
	* nto-procfs.c (procfs_detach): Likewise.
	* procfs.c (procfs_detach): Likewise.
	* record.c (record_detach): Likewise.
	* record.h (struct inferior): Forward-declare.
	(record_detach): Add inferior parameter.
	* remote-sim.c (gdbsim_detach): Likewise.
	* remote.c (remote_detach_1): Likewise.
	(remote_detach): Likewise.
	(extended_remote_detach): Likewise.
	* sol-thread.c (sol_thread_detach): Likewise.
	* target-debug.h (target_debug_print_inferior_p): New macro.
	* target-delegates.c: Re-generate.
	* top.c (kill_or_detach): Pass inferior down to target_detach.
	* windows-nat.c (windows_detach): Add inferior parameter.

24 files changed, 89 insertions, 41 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d96da26..4a994b4 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,42 @@
 2018-01-19  Simon Marchi  <simon.marchi@ericsson.com>
 
+	* target.h (struct target_ops) <to_detach>: Add inferior
+	parameter.
+	(target_detach): Likewise.
+	* target.c (dispose_inferior): Pass inferior down.
+	(target_detach): Pass inferior down.  Assert that it is equal to
+	the current inferior.
+	* aix-thread.c (aix_thread_detach): Pass inferior down.
+	* corefile.c (core_file_command): Pass current_inferior() down.
+	* corelow.c (core_detach): Add inferior parameter.
+	* darwin-nat.c (darwin_detach): Likewise.
+	* gnu-nat.c (gnu_detach): Likewise.
+	* inf-ptrace.c (inf_ptrace_detach): Likewise.
+	* infcmd.c (detach_command): Pass current_inferior() down to
+	target_detach.
+	* infrun.c (follow_fork_inferior): Pass parent_inf to
+	target_detach.
+	(handle_vfork_child_exec_or_exit): Pass inf->vfork_parent to
+	target_detach.
+	* linux-nat.c (linux_nat_detach): Add inferior parameter.
+	* linux-thread-db.c (thread_db_detach): Likewise.
+	* nto-procfs.c (procfs_detach): Likewise.
+	* procfs.c (procfs_detach): Likewise.
+	* record.c (record_detach): Likewise.
+	* record.h (struct inferior): Forward-declare.
+	(record_detach): Add inferior parameter.
+	* remote-sim.c (gdbsim_detach): Likewise.
+	* remote.c (remote_detach_1): Likewise.
+	(remote_detach): Likewise.
+	(extended_remote_detach): Likewise.
+	* sol-thread.c (sol_thread_detach): Likewise.
+	* target-debug.h (target_debug_print_inferior_p): New macro.
+	* target-delegates.c: Re-generate.
+	* top.c (kill_or_detach): Pass inferior down to target_detach.
+	* windows-nat.c (windows_detach): Add inferior parameter.
+
+2018-01-19  Simon Marchi  <simon.marchi@ericsson.com>
+
 	* target.h (struct target_ops) <to_detach>: Remove args
 	parameter.
 	(target_detach): Likewise.
diff --git a/gdb/aix-thread.c b/gdb/aix-thread.c
index 0f0404f..09d5175 100644
--- a/gdb/aix-thread.c
+++ b/gdb/aix-thread.c
@@ -981,12 +981,12 @@ aix_thread_inferior_created (struct target_ops *ops, int from_tty)
 /* Detach from the process attached to by aix_thread_attach().  */
 
 static void
-aix_thread_detach (struct target_ops *ops, int from_tty)
+aix_thread_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   struct target_ops *beneath = find_target_beneath (ops);
 
   pd_disable ();
-  beneath->to_detach (beneath, from_tty);
+  beneath->to_detach (beneath, inf, from_tty);
 }
 
 /* Tell the inferior process to continue running thread PID if != -1
diff --git a/gdb/corefile.c b/gdb/corefile.c
index c5e4f91..abf9ea6 100644
--- a/gdb/corefile.c
+++ b/gdb/corefile.c
@@ -68,7 +68,7 @@ core_file_command (const char *filename, int from_tty)
   gdb_assert (core_target != NULL);
 
   if (!filename)
-    (core_target->to_detach) (core_target, from_tty);
+    (core_target->to_detach) (core_target, current_inferior (), from_tty);
   else
     (core_target->to_open) (filename, from_tty);
 }
diff --git a/gdb/corelow.c b/gdb/corelow.c
index 250f46a..190f016 100644
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -464,7 +464,7 @@ core_open (const char *arg, int from_tty)
 }
 
 static void
-core_detach (struct target_ops *ops, int from_tty)
+core_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   unpush_target (ops);
   reinit_frame_cache ();
diff --git a/gdb/darwin-nat.c b/gdb/darwin-nat.c
index 1441a6a..7a862cd 100644
--- a/gdb/darwin-nat.c
+++ b/gdb/darwin-nat.c
@@ -1938,10 +1938,9 @@ darwin_attach (struct target_ops *ops, const char *args, int from_tty)
    previously attached.  It *might* work if the program was
    started via fork.  */
 static void
-darwin_detach (struct target_ops *ops, int from_tty)
+darwin_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   pid_t pid = ptid_get_pid (inferior_ptid);
-  struct inferior *inf = current_inferior ();
   darwin_inferior *priv = get_darwin_inferior (inf);
   kern_return_t kret;
   int res;
diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
index 0debb02..8271565 100644
--- a/gdb/gnu-nat.c
+++ b/gdb/gnu-nat.c
@@ -2255,7 +2255,7 @@ gnu_attach (struct target_ops *ops, const char *args, int from_tty)
    previously attached.  It *might* work if the program was
    started via fork.  */
 static void
-gnu_detach (struct target_ops *ops, int from_tty)
+gnu_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   int pid;
 
diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c
index 44216c4..aa8b17f 100644
--- a/gdb/inf-ptrace.c
+++ b/gdb/inf-ptrace.c
@@ -244,7 +244,7 @@ inf_ptrace_post_attach (struct target_ops *self, int pid)
 /* Detach from the inferior.  If FROM_TTY is non-zero, be chatty about it.  */
 
 static void
-inf_ptrace_detach (struct target_ops *ops, int from_tty)
+inf_ptrace_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   pid_t pid = ptid_get_pid (inferior_ptid);
 
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 8865244..4ad37aa 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -2976,7 +2976,7 @@ detach_command (const char *args, int from_tty)
 
   disconnect_tracing ();
 
-  target_detach (from_tty);
+  target_detach (current_inferior (), from_tty);
 
   /* The current inferior process was just detached successfully.  Get
      rid of breakpoints that no longer make sense.  Note we don't do
diff --git a/gdb/infrun.c b/gdb/infrun.c
index d240208..45fe36a 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -606,7 +606,7 @@ holding the child stopped.  Try \"set detach-on-fork\" or \
 				target_pid_to_str (process_ptid));
 	    }
 
-	  target_detach (0);
+	  target_detach (parent_inf, 0);
 	}
 
       /* Note that the detach above makes PARENT_INF dangling.  */
@@ -976,7 +976,7 @@ handle_vfork_child_exec_or_exit (int exec)
 		}
 	    }
 
-	  target_detach (0);
+	  target_detach (inf->vfork_parent, 0);
 
 	  /* Put it back.  */
 	  inf->pspace = pspace;
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 99d12f2..70f4c08 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1497,7 +1497,7 @@ detach_callback (struct lwp_info *lp, void *data)
 }
 
 static void
-linux_nat_detach (struct target_ops *ops, int from_tty)
+linux_nat_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   int pid;
   struct lwp_info *main_lwp;
diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c
index 9dcfc0e..873f929 100644
--- a/gdb/linux-thread-db.c
+++ b/gdb/linux-thread-db.c
@@ -1090,13 +1090,13 @@ record_thread (struct thread_db_info *info,
 }
 
 static void
-thread_db_detach (struct target_ops *ops, int from_tty)
+thread_db_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   struct target_ops *target_beneath = find_target_beneath (ops);
 
   delete_thread_db_info (ptid_get_pid (inferior_ptid));
 
-  target_beneath->to_detach (target_beneath, from_tty);
+  target_beneath->to_detach (target_beneath, inf, from_tty);
 
   /* NOTE: From this point on, inferior_ptid is null_ptid.  */
 
diff --git a/gdb/nto-procfs.c b/gdb/nto-procfs.c
index 2fd2dcf..6408c21 100644
--- a/gdb/nto-procfs.c
+++ b/gdb/nto-procfs.c
@@ -943,7 +943,7 @@ procfs_xfer_partial (struct target_ops *ops, enum target_object object,
    on signals, etc.  We'd better not have left any breakpoints
    in the program or it'll die when it hits one.  */
 static void
-procfs_detach (struct target_ops *ops, int from_tty)
+procfs_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   int pid;
 
diff --git a/gdb/procfs.c b/gdb/procfs.c
index 491970a..2d5ec65 100644
--- a/gdb/procfs.c
+++ b/gdb/procfs.c
@@ -1924,7 +1924,7 @@ procfs_attach (struct target_ops *ops, const char *args, int from_tty)
 }
 
 static void
-procfs_detach (struct target_ops *ops, int from_tty)
+procfs_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   int pid = ptid_get_pid (inferior_ptid);
 
diff --git a/gdb/record.c b/gdb/record.c
index 74a14dc..9a47614 100644
--- a/gdb/record.c
+++ b/gdb/record.c
@@ -187,7 +187,7 @@ record_disconnect (struct target_ops *t, const char *args, int from_tty)
 /* See record.h.  */
 
 void
-record_detach (struct target_ops *t, int from_tty)
+record_detach (struct target_ops *t, inferior *inf, int from_tty)
 {
   gdb_assert (t->to_stratum == record_stratum);
 
@@ -196,7 +196,7 @@ record_detach (struct target_ops *t, int from_tty)
   record_stop (t);
   record_unpush (t);
 
-  target_detach (from_tty);
+  target_detach (inf, from_tty);
 }
 
 /* See record.h.  */
diff --git a/gdb/record.h b/gdb/record.h
index a0ca84d..21fafeb 100644
--- a/gdb/record.h
+++ b/gdb/record.h
@@ -24,6 +24,7 @@
 #include "common/enum-flags.h"
 
 struct cmd_list_element;
+struct inferior;
 
 extern unsigned int record_debug;
 
@@ -88,7 +89,7 @@ extern void record_goto (const char *arg);
 extern void record_disconnect (struct target_ops *, const char *, int);
 
 /* The default "to_detach" target method for record targets.  */
-extern void record_detach (struct target_ops *, int);
+extern void record_detach (struct target_ops *, inferior *, int);
 
 /* The default "to_mourn_inferior" target method for record targets.  */
 extern void record_mourn_inferior (struct target_ops *);
diff --git a/gdb/remote-sim.c b/gdb/remote-sim.c
index edc70d5..aed7a34 100644
--- a/gdb/remote-sim.c
+++ b/gdb/remote-sim.c
@@ -77,7 +77,7 @@ static void gdbsim_open (const char *args, int from_tty);
 
 static void gdbsim_close (struct target_ops *self);
 
-static void gdbsim_detach (struct target_ops *ops, int from_tty);
+static void gdbsim_detach (struct target_ops *ops, inferior *inf, int from_tty);
 
 static void gdbsim_prepare_to_store (struct target_ops *self,
 				     struct regcache *regcache);
@@ -820,7 +820,7 @@ gdbsim_close (struct target_ops *self)
    Use this when you want to detach and do something else with your gdb.  */
 
 static void
-gdbsim_detach (struct target_ops *ops, int from_tty)
+gdbsim_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   if (remote_debug)
     fprintf_unfiltered (gdb_stdlog, "gdbsim_detach\n");
diff --git a/gdb/remote.c b/gdb/remote.c
index 01b236f..5ac84df 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -5126,7 +5126,7 @@ remote_detach_pid (int pid)
    one.  */
 
 static void
-remote_detach_1 (int from_tty)
+remote_detach_1 (int from_tty, inferior *inf)
 {
   int pid = ptid_get_pid (inferior_ptid);
   struct remote_state *rs = get_remote_state ();
@@ -5162,15 +5162,15 @@ remote_detach_1 (int from_tty)
 }
 
 static void
-remote_detach (struct target_ops *ops, int from_tty)
+remote_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
-  remote_detach_1 (from_tty);
+  remote_detach_1 (from_tty, inf);
 }
 
 static void
-extended_remote_detach (struct target_ops *ops, int from_tty)
+extended_remote_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
-  remote_detach_1 (from_tty);
+  remote_detach_1 (from_tty, inf);
 }
 
 /* Target follow-fork function for remote targets.  On entry, and
diff --git a/gdb/sol-thread.c b/gdb/sol-thread.c
index e724c7e..2c7dd0e 100644
--- a/gdb/sol-thread.c
+++ b/gdb/sol-thread.c
@@ -348,14 +348,14 @@ lwp_to_thread (ptid_t lwp)
    program was started via the normal ptrace (PTRACE_TRACEME).  */
 
 static void
-sol_thread_detach (struct target_ops *ops, int from_tty)
+sol_thread_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   struct target_ops *beneath = find_target_beneath (ops);
 
   sol_thread_active = 0;
   inferior_ptid = pid_to_ptid (ptid_get_pid (main_ph.ptid));
   unpush_target (ops);
-  beneath->to_detach (beneath, from_tty);
+  beneath->to_detach (beneath, inf, from_tty);
 }
 
 /* Resume execution of process PTID.  If STEP is nozero, then just
diff --git a/gdb/target-debug.h b/gdb/target-debug.h
index d7d99ef..d7fc001 100644
--- a/gdb/target-debug.h
+++ b/gdb/target-debug.h
@@ -170,6 +170,8 @@
   target_debug_do_print (host_address_to_string (X.get ()))
 #define target_debug_print_gdb_array_view_const_int(X)	\
   target_debug_do_print (host_address_to_string (X.data ()))
+#define target_debug_print_inferior_p(inf) \
+  target_debug_do_print (host_address_to_string (inf))
 
 static void
 target_debug_print_struct_target_waitstatus_p (struct target_waitstatus *status)
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
index 6bb7d7f..bc84791 100644
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -28,26 +28,28 @@ debug_post_attach (struct target_ops *self, int arg1)
 }
 
 static void
-delegate_detach (struct target_ops *self, int arg1)
+delegate_detach (struct target_ops *self, inferior *arg1, int arg2)
 {
   self = self->beneath;
-  self->to_detach (self, arg1);
+  self->to_detach (self, arg1, arg2);
 }
 
 static void
-tdefault_detach (struct target_ops *self, int arg1)
+tdefault_detach (struct target_ops *self, inferior *arg1, int arg2)
 {
 }
 
 static void
-debug_detach (struct target_ops *self, int arg1)
+debug_detach (struct target_ops *self, inferior *arg1, int arg2)
 {
   fprintf_unfiltered (gdb_stdlog, "-> %s->to_detach (...)\n", debug_target.to_shortname);
-  debug_target.to_detach (&debug_target, arg1);
+  debug_target.to_detach (&debug_target, arg1, arg2);
   fprintf_unfiltered (gdb_stdlog, "<- %s->to_detach (", debug_target.to_shortname);
   target_debug_print_struct_target_ops_p (&debug_target);
   fputs_unfiltered (", ", gdb_stdlog);
-  target_debug_print_int (arg1);
+  target_debug_print_inferior_p (arg1);
+  fputs_unfiltered (", ", gdb_stdlog);
+  target_debug_print_int (arg2);
   fputs_unfiltered (")\n", gdb_stdlog);
 }
 
diff --git a/gdb/target.c b/gdb/target.c
index b01e1ac..ce630f4 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -2108,7 +2108,7 @@ dispose_inferior (struct inferior *inf, void *args)
       if (target_has_execution)
 	target_kill ();
       else
-	target_detach (0);
+	target_detach (inf, 0);
     }
 
   return 0;
@@ -2144,8 +2144,15 @@ target_preopen (int from_tty)
 /* See target.h.  */
 
 void
-target_detach (int from_tty)
+target_detach (inferior *inf, int from_tty)
 {
+  /* As long as some to_detach implementations rely on the current_inferior
+     (either directly, or indirectly, like through target_gdbarch or by
+     reading memory), INF needs to be the current inferior.  When that
+     requirement will become no longer true, then we can remove this
+     assertion.  */
+  gdb_assert (inf == current_inferior ());
+
   if (gdbarch_has_global_breakpoints (target_gdbarch ()))
     /* Don't remove global breakpoints here.  They're removed on
        disconnection from the target.  */
@@ -2157,7 +2164,7 @@ target_detach (int from_tty)
 
   prepare_for_detach ();
 
-  current_target.to_detach (&current_target, from_tty);
+  current_target.to_detach (&current_target, inf, from_tty);
 }
 
 void
diff --git a/gdb/target.h b/gdb/target.h
index 51841a1..52361ba 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -440,7 +440,7 @@ struct target_ops
     void (*to_attach) (struct target_ops *ops, const char *, int);
     void (*to_post_attach) (struct target_ops *, int)
       TARGET_DEFAULT_IGNORE ();
-    void (*to_detach) (struct target_ops *ops, int)
+    void (*to_detach) (struct target_ops *ops, inferior *, int)
       TARGET_DEFAULT_IGNORE ();
     void (*to_disconnect) (struct target_ops *, const char *, int)
       TARGET_DEFAULT_NORETURN (tcomplain ());
@@ -1326,7 +1326,7 @@ extern void target_announce_detach (int from_tty);
    in the program or it'll die when it hits one.  FROM_TTY says whether to be
    verbose or not.  */
 
-extern void target_detach (int from_tty);
+extern void target_detach (inferior *inf, int from_tty);
 
 /* Disconnect from the current target without resuming it (leaving it
    waiting for a debugger).  */
diff --git a/gdb/top.c b/gdb/top.c
index 1e6d513..a6166bd 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1485,7 +1485,7 @@ kill_or_detach (struct inferior *inf, void *args)
       if (target_has_execution)
 	{
 	  if (inf->attach_flag)
-	    target_detach (qt->from_tty);
+	    target_detach (inf, qt->from_tty);
 	  else
 	    target_kill ();
 	}
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 4023089..5fb143e 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -1931,7 +1931,7 @@ windows_attach (struct target_ops *ops, const char *args, int from_tty)
 }
 
 static void
-windows_detach (struct target_ops *ops, int from_tty)
+windows_detach (struct target_ops *ops, inferior *inf, int from_tty)
 {
   int detached = 1;