Share Windows thread-suspend and -resume code

This adds "suspend" and "resume" methods to windows_thread_info, and
changes gdb and gdbserver to share this code.

gdb/ChangeLog
2020-04-08  Tom Tromey  <tromey@adacore.com>

	* windows-nat.c (thread_rec): Use windows_thread_info::suspend.
	(windows_continue): Use windows_continue::resume.
	* nat/windows-nat.h (struct windows_thread_info) <suspend,
	resume>: Declare new methods.
	* nat/windows-nat.c: New file.
	* configure.nat (NATDEPFILES): Add nat/windows-nat.o when needed.

gdbserver/ChangeLog
2020-04-08  Tom Tromey  <tromey@adacore.com>

	* win32-low.c (win32_require_context, suspend_one_thread): Use
	windows_thread_info::suspend.
	(continue_one_thread): Use windows_thread_info::resume.
	* configure.srv (srv_tgtobj): Add windows-nat.o when needed.

3 files changed, 16 insertions, 31 deletions

diff --git a/gdbserver/ChangeLog b/gdbserver/ChangeLog
index 25b5768..29d1760 100644
--- a/gdbserver/ChangeLog
+++ b/gdbserver/ChangeLog
@@ -1,5 +1,12 @@
 2020-04-08  Tom Tromey  <tromey@adacore.com>
 
+	* win32-low.c (win32_require_context, suspend_one_thread): Use
+	windows_thread_info::suspend.
+	(continue_one_thread): Use windows_thread_info::resume.
+	* configure.srv (srv_tgtobj): Add windows-nat.o when needed.
+
+2020-04-08  Tom Tromey  <tromey@adacore.com>
+
 	* win32-i386-low.c (update_debug_registers)
 	(i386_prepare_to_resume, i386_thread_added): Update.
 
diff --git a/gdbserver/configure.srv b/gdbserver/configure.srv
index ecdd63a..7acf229 100644
--- a/gdbserver/configure.srv
+++ b/gdbserver/configure.srv
@@ -74,7 +74,7 @@ case "${gdbserver_host}" in
 			srv_linux_thread_db=yes
 			;;
   arm*-*-mingw32ce*)	srv_regobj=reg-arm.o
-			srv_tgtobj="win32-low.o win32-arm-low.o"
+			srv_tgtobj="win32-low.o windows-nat.o win32-arm-low.o"
 			srv_tgtobj="${srv_tgtobj} wincecompat.o"
 			# hostio_last_error implementation is in win32-low.c
 			srv_hostio_err_objs=""
@@ -99,6 +99,7 @@ case "${gdbserver_host}" in
   i[34567]86-*-cygwin*)	srv_regobj=""
 			srv_tgtobj="x86-low.o nat/x86-dregs.o win32-low.o"
 			srv_tgtobj="${srv_tgtobj} win32-i386-low.o"
+			srv_tgtobj="${srv_tgtobj} nat/windows-nat.o"
 			srv_tgtobj="${srv_tgtobj} arch/i386.o"
 			;;
   i[34567]86-*-linux*)	srv_tgtobj="${srv_tgtobj} arch/i386.o"
@@ -126,6 +127,7 @@ case "${gdbserver_host}" in
 			srv_regobj=""
 			srv_tgtobj="x86-low.o nat/x86-dregs.o win32-low.o"
 			srv_tgtobj="${srv_tgtobj} win32-i386-low.o"
+			srv_tgtobj="${srv_tgtobj} nat/windows-nat.o"
 			srv_tgtobj="${srv_tgtobj} arch/i386.o"
 			srv_tgtobj="${srv_tgtobj} wincecompat.o"
 			# hostio_last_error implementation is in win32-low.c
@@ -136,6 +138,7 @@ case "${gdbserver_host}" in
   i[34567]86-*-mingw*)	srv_regobj=""
 			srv_tgtobj="x86-low.o nat/x86-dregs.o win32-low.o"
 			srv_tgtobj="${srv_tgtobj} win32-i386-low.o"
+			srv_tgtobj="${srv_tgtobj} nat/windows-nat.o"
 			srv_tgtobj="${srv_tgtobj} arch/i386.o"
 			srv_mingw=yes
 			;;
@@ -393,12 +396,14 @@ case "${gdbserver_host}" in
   x86_64-*-mingw*)	srv_regobj=""
 			srv_tgtobj="x86-low.o nat/x86-dregs.o i387-fp.o"
 			srv_tgtobj="${srv_tgtobj} win32-low.o win32-i386-low.o"
+			srv_tgtobj="${srv_tgtobj} nat/windows-nat.o"
 			srv_tgtobj="${srv_tgtobj} arch/amd64.o"
 			srv_mingw=yes
 			;;
   x86_64-*-cygwin*)	srv_regobj=""
 			srv_tgtobj="x86-low.o nat/x86-dregs.o i387-fp.o"
 			srv_tgtobj="${srv_tgtobj} win32-low.o win32-i386-low.o"
+			srv_tgtobj="${srv_tgtobj} nat/windows-nat.o"
 			srv_tgtobj="${srv_tgtobj} arch/amd64.o"
 			;;
 
diff --git a/gdbserver/win32-low.cc b/gdbserver/win32-low.cc
index 1284ed1..7cad640 100644
--- a/gdbserver/win32-low.cc
+++ b/gdbserver/win32-low.cc
@@ -171,18 +171,7 @@ win32_require_context (windows_thread_info *th)
 {
   if (th->context.ContextFlags == 0)
     {
-      if (!th->suspended)
-	{
-	  if (SuspendThread (th->h) == (DWORD) -1)
-	    {
-	      DWORD err = GetLastError ();
-	      OUTMSG (("warning: SuspendThread failed in thread_rec, "
-		       "(error %d): %s\n", (int) err, strwinerror (err)));
-	    }
-	  else
-	    th->suspended = 1;
-	}
-
+      th->suspend ();
       win32_get_thread_context (th);
     }
 }
@@ -435,13 +424,7 @@ continue_one_thread (thread_info *thread, int thread_id)
 	      th->context.ContextFlags = 0;
 	    }
 
-	  if (ResumeThread (th->h) == (DWORD) -1)
-	    {
-	      DWORD err = GetLastError ();
-	      OUTMSG (("warning: ResumeThread failed in continue_one_thread, "
-		       "(error %d): %s\n", (int) err, strwinerror (err)));
-	    }
-	  th->suspended = 0;
+	  th->resume ();
 	}
     }
 }
@@ -1348,17 +1331,7 @@ suspend_one_thread (thread_info *thread)
 {
   windows_thread_info *th = (windows_thread_info *) thread_target_data (thread);
 
-  if (!th->suspended)
-    {
-      if (SuspendThread (th->h) == (DWORD) -1)
-	{
-	  DWORD err = GetLastError ();
-	  OUTMSG (("warning: SuspendThread failed in suspend_one_thread, "
-		   "(error %d): %s\n", (int) err, strwinerror (err)));
-	}
-      else
-	th->suspended = 1;
-    }
+  th->suspend ();
 }
 
 static void