[PATCH 09/26] gdbserver: extract out regcache::invalidate and regcache::discard

[Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>]

Extract out a piece of code from the `regcache_invalidate_thread`
function and turn into a new method of regcache named 'invalidate'.

We also introduce a small method named 'discard' to give the clients
an option to discard the cache without storing the contents.  This
method is utilized in a downstream debugger.
---
 gdbserver/regcache.cc | 24 +++++++++++++++++-------
 gdbserver/regcache.h  |  6 ++++++
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/gdbserver/regcache.cc b/gdbserver/regcache.cc
index 7b6337166ad..1db78951cc2 100644
--- a/gdbserver/regcache.cc
+++ b/gdbserver/regcache.cc
@@ -85,18 +85,22 @@ regcache_invalidate_thread (struct thread_info *thread)
 
   regcache = thread_regcache_data (thread);
 
-  if (regcache == NULL)
-    return;
+  if (regcache != nullptr)
+    regcache->invalidate ();
+}
 
-  if (regcache->registers_valid)
+void
+regcache::invalidate ()
+{
+  if (registers_valid)
     {
       scoped_restore_current_thread restore_thread;
-
-      switch_to_thread (thread);
-      store_inferior_registers (regcache, -1);
+      gdb_assert (this->thread != nullptr);
+      switch_to_thread (this->thread);
+      store_inferior_registers (this, -1);
     }
 
-  regcache->registers_valid = 0;
+  discard ();
 }
 
 /* See regcache.h.  */
@@ -121,6 +125,12 @@ regcache_invalidate (void)
 
 #endif
 
+void
+regcache::discard ()
+{
+  registers_valid = 0;
+}
+
 void
 regcache::initialize (const target_desc *tdesc,
 		      unsigned char *regbuf)
diff --git a/gdbserver/regcache.h b/gdbserver/regcache.h
index 614d5a2561f..b4a9d8864ae 100644
--- a/gdbserver/regcache.h
+++ b/gdbserver/regcache.h
@@ -78,6 +78,12 @@ struct regcache : public reg_buffer_common
 
   /* Copy the contents of SRC into this regcache.  */
   void copy_from (regcache *src);
+
+  /* Store the cached registers to the target and then discard the cache.  */
+  void invalidate ();
+
+  /* Discard the cache without storing the registers to the target.  */
+  void discard ();
 };
 
 regcache *get_thread_regcache (thread_info *thread, bool fetch = true);
-- 
2.25.1

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