Windows gdb+gdbserver: New find_thread, replaces thread_rec(DONT_INVALIDATE_CONTEXT)

The goal of the next few patches is to eliminate thread_rec
completely.  This is the first patch in that effort.

thread_rec(DONT_INVALIDATE_CONTEXT) is really just a thread lookup
with no side effects, so this adds a find_thread function that lets
you do that.

Change-Id: Ie486badce00e234b10caa478b066c34537103e3f

2 files changed, 19 insertions, 12 deletions

diff --git a/gdbserver/win32-low.cc b/gdbserver/win32-low.cc
index cc314df..5a57eed 100644
--- a/gdbserver/win32-low.cc
+++ b/gdbserver/win32-low.cc
@@ -142,6 +142,17 @@ win32_require_context (windows_thread_info *th)
 /* See nat/windows-nat.h.  */
 
 windows_thread_info *
+gdbserver_windows_process::find_thread (ptid_t ptid)
+{
+  thread_info *thread = find_thread_ptid (ptid);
+  if (thread == nullptr)
+    return nullptr;
+  return (windows_thread_info *) thread_target_data (thread);
+}
+
+/* See nat/windows-nat.h.  */
+
+windows_thread_info *
 gdbserver_windows_process::thread_rec
      (ptid_t ptid, thread_disposition_type disposition)
 {
@@ -150,8 +161,7 @@ gdbserver_windows_process::thread_rec
     return NULL;
 
   windows_thread_info *th = (windows_thread_info *) thread_target_data (thread);
-  if (disposition != DONT_INVALIDATE_CONTEXT)
-    win32_require_context (th);
+  win32_require_context (th);
   return th;
 }
 
@@ -162,7 +172,7 @@ child_add_thread (DWORD pid, DWORD tid, HANDLE h, void *tlb)
   windows_thread_info *th;
   ptid_t ptid = ptid_t (pid, tid, 0);
 
-  if ((th = windows_process.thread_rec (ptid, DONT_INVALIDATE_CONTEXT)))
+  if ((th = windows_process.find_thread (ptid)))
     return th;
 
   CORE_ADDR base = (CORE_ADDR) (uintptr_t) tlb;
@@ -822,7 +832,7 @@ win32_process_target::resume (thread_resume *resume_info, size_t n)
 
   /* Get context for the currently selected thread.  */
   ptid = debug_event_ptid (&windows_process.current_event);
-  th = windows_process.thread_rec (ptid, DONT_INVALIDATE_CONTEXT);
+  th = windows_process.find_thread (ptid);
   if (th)
     {
       win32_prepare_to_resume (th);
@@ -974,8 +984,7 @@ maybe_adjust_pc ()
   child_fetch_inferior_registers (regcache, -1);
 
   windows_thread_info *th
-    = windows_process.thread_rec (current_thread_ptid (),
-				  DONT_INVALIDATE_CONTEXT);
+    = windows_process.find_thread (current_thread_ptid ());
   th->stopped_at_software_breakpoint = false;
 
   if (windows_process.current_event.dwDebugEventCode == EXCEPTION_DEBUG_EVENT
@@ -1375,8 +1384,7 @@ win32_process_target::supports_get_tib_address ()
 int
 win32_process_target::get_tib_address (ptid_t ptid, CORE_ADDR *addr)
 {
-  windows_thread_info *th;
-  th = windows_process.thread_rec (ptid, DONT_INVALIDATE_CONTEXT);
+  windows_thread_info *th = windows_process.find_thread (ptid);
   if (th == NULL)
     return 0;
   if (addr != NULL)
@@ -1397,8 +1405,7 @@ bool
 win32_process_target::stopped_by_sw_breakpoint ()
 {
   windows_thread_info *th
-    = windows_process.thread_rec (current_thread_ptid (),
-				  DONT_INVALIDATE_CONTEXT);
+    = windows_process.find_thread (current_thread_ptid ());
   return th == nullptr ? false : th->stopped_at_software_breakpoint;
 }
 
@@ -1424,8 +1431,7 @@ const char *
 win32_process_target::thread_name (ptid_t thread)
 {
   windows_thread_info *th
-    = windows_process.thread_rec (current_thread_ptid (),
-				  DONT_INVALIDATE_CONTEXT);
+    = windows_process.find_thread (current_thread_ptid ());
   return th->thread_name ();
 }
 
diff --git a/gdbserver/win32-low.h b/gdbserver/win32-low.h
index ff997df..c725c18 100644
--- a/gdbserver/win32-low.h
+++ b/gdbserver/win32-low.h
@@ -174,6 +174,7 @@ public:
 
 struct gdbserver_windows_process : public windows_nat::windows_process_info
 {
+  windows_nat::windows_thread_info *find_thread (ptid_t ptid) override;
   windows_nat::windows_thread_info *thread_rec
        (ptid_t ptid,
 	windows_nat::thread_disposition_type disposition) override;