Introduce common-regcache.h

This introduces common-regcache.h.  This contains two functions that
allow nat/linux-btrace.c to be simplified.  A better long term
solution would be unify the regcache code, but this is sufficient for
now.

gdb/ChangeLog:

	* common/common-regcache.h: New file.
	* Makefile.in (HFILES_NO_SRCDIR): Add common/common-regcache.h.
	* regcache.h: Include common-regcache.h.
	(regcache_read_pc): Don't declare.
	* regcache.c (get_thread_regcache_for_ptid): New function.
	* nat/linux-btrace.c: Don't include regcache.h.
	Include common-regcache.h.
	(perf_event_read_bts): Use get_thread_regcache_for_ptid.

gdb/gdbserver/ChangeLog:

	* regcache.h: Include common-regcache.h.
	(regcache_read_pc): Don't declare.
	* regcache.c (get_thread_regcache_for_ptid): New function.

9 files changed, 80 insertions, 9 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 30112cb..96d65ae 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,15 @@
+2014-09-12  Tom Tromey  <tromey@redhat.com>
+	    Gary Benson  <gbenson@redhat.com>
+
+	* common/common-regcache.h: New file.
+	* Makefile.in (HFILES_NO_SRCDIR): Add common/common-regcache.h.
+	* regcache.h: Include common-regcache.h.
+	(regcache_read_pc): Don't declare.
+	* regcache.c (get_thread_regcache_for_ptid): New function.
+	* nat/linux-btrace.c: Don't include regcache.h.
+	Include common-regcache.h.
+	(perf_event_read_bts): Use get_thread_regcache_for_ptid.
+
 2014-09-11  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* regcache.h (struct regset): Declare.
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index f6b9176..cbec0d2 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -938,7 +938,8 @@ target/wait.h target/waitstatus.h nat/linux-nat.h nat/linux-waitpid.h \
 common/print-utils.h common/rsp-low.h nat/x86-dregs.h x86-linux-nat.h \
 i386-linux-nat.h common/common-defs.h common/errors.h common/common-types.h \
 common/common-debug.h common/cleanups.h common/gdb_setjmp.h \
-common/common-exceptions.h target/target.h common/symbol.h
+common/common-exceptions.h target/target.h common/symbol.h \
+common/common-regcache.h
 
 # Header files that already have srcdir in them, or which are in objdir.
 
diff --git a/gdb/common/common-regcache.h b/gdb/common/common-regcache.h
new file mode 100644
index 0000000..2825c7f
--- /dev/null
+++ b/gdb/common/common-regcache.h
@@ -0,0 +1,36 @@
+/* Cache and manage the values of registers
+
+   Copyright (C) 2014 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef COMMON_REGCACHE_H
+#define COMMON_REGCACHE_H
+
+/* This header is a stopgap until we have an independent regcache.  */
+
+/* Return a pointer to the register cache associated with the
+   thread specified by PTID.  This function must be provided by
+   the client.  */
+
+extern struct regcache *get_thread_regcache_for_ptid (ptid_t ptid);
+
+/* Read the PC register.  This function must be provided by the
+   client.  */
+
+extern CORE_ADDR regcache_read_pc (struct regcache *regcache);
+
+#endif /* COMMON_REGCACHE_H */
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 0ea5a42..f88eb31 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,10 @@
+2014-09-12  Tom Tromey  <tromey@redhat.com>
+	    Gary Benson  <gbenson@redhat.com>
+
+	* regcache.h: Include common-regcache.h.
+	(regcache_read_pc): Don't declare.
+	* regcache.c (get_thread_regcache_for_ptid): New function.
+
 2014-09-11  Tom Tromey  <tromey@redhat.com>
 	    Gary Benson  <gbenson@redhat.com>
 
diff --git a/gdb/gdbserver/regcache.c b/gdb/gdbserver/regcache.c
index fda2069..ad66ff7 100644
--- a/gdb/gdbserver/regcache.c
+++ b/gdb/gdbserver/regcache.c
@@ -60,6 +60,14 @@ get_thread_regcache (struct thread_info *thread, int fetch)
   return regcache;
 }
 
+/* See common/common-regcache.h.  */
+
+struct regcache *
+get_thread_regcache_for_ptid (ptid_t ptid)
+{
+  return get_thread_regcache (find_thread_ptid (ptid), 1);
+}
+
 void
 regcache_invalidate_thread (struct thread_info *thread)
 {
diff --git a/gdb/gdbserver/regcache.h b/gdb/gdbserver/regcache.h
index 891fead..bf2e51f 100644
--- a/gdb/gdbserver/regcache.h
+++ b/gdb/gdbserver/regcache.h
@@ -19,6 +19,8 @@
 #ifndef REGCACHE_H
 #define REGCACHE_H
 
+#include "common-regcache.h"
+
 struct thread_info;
 struct target_desc;
 
@@ -91,7 +93,7 @@ void registers_to_string (struct regcache *regcache, char *buf);
 
 void registers_from_string (struct regcache *regcache, char *buf);
 
-CORE_ADDR regcache_read_pc (struct regcache *regcache);
+/* For regcache_read_pc see common/common-regcache.h.  */
 
 void regcache_write_pc (struct regcache *regcache, CORE_ADDR pc);
 
diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index e0106fa..385ca4e 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -26,7 +26,7 @@
 #endif
 
 #include "linux-btrace.h"
-#include "regcache.h"
+#include "common-regcache.h"
 #include "gdbthread.h"
 #include "gdb_wait.h"
 #include "x86-cpuid.h"
@@ -180,11 +180,7 @@ perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin,
   gdb_assert (start <= end);
 
   /* The first block ends at the current pc.  */
-#ifdef GDBSERVER
-  regcache = get_thread_regcache (find_thread_ptid (tinfo->ptid), 1);
-#else
-  regcache = get_thread_regcache (tinfo->ptid);
-#endif
+  regcache = get_thread_regcache_for_ptid (tinfo->ptid);
   block.end = regcache_read_pc (regcache);
 
   /* The buffer may contain a partial record as its last entry (i.e. when the
diff --git a/gdb/regcache.c b/gdb/regcache.c
index 05b8fb9..9b6c794 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -536,6 +536,13 @@ get_current_regcache (void)
   return get_thread_regcache (inferior_ptid);
 }
 
+/* See common/common-regcache.h.  */
+
+struct regcache *
+get_thread_regcache_for_ptid (ptid_t ptid)
+{
+  return get_thread_regcache (ptid);
+}
 
 /* Observer for the target_changed event.  */
 
diff --git a/gdb/regcache.h b/gdb/regcache.h
index 0e0b84b..c00da84 100644
--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -20,6 +20,8 @@
 #ifndef REGCACHE_H
 #define REGCACHE_H
 
+#include "common-regcache.h"
+
 struct regcache;
 struct regset;
 struct gdbarch;
@@ -136,7 +138,7 @@ void regcache_cooked_write_part (struct regcache *regcache, int regnum,
 
 /* Special routines to read/write the PC.  */
 
-extern CORE_ADDR regcache_read_pc (struct regcache *regcache);
+/* For regcache_read_pc see common/common-regcache.h.  */
 extern void regcache_write_pc (struct regcache *regcache, CORE_ADDR pc);
 
 /* Transfer a raw register [0..NUM_REGS) between the regcache and the