gdb/gdbserver/

	* regcache.c (init_register_cache): Initialize
	regcache->register_status.
	(free_register_cache): Release regcache->register_status.
	(regcache_cpy): Copy register_status.
	(registers_to_string): Print 'x's for unavailable registers.
	(supply_register): Mark the register's status valid or
	unavailable, depending on whether a buffer was passed in or not.
	(supply_register_zeroed): New.
	(supply_regblock): Mark the registers' status valid or
	unavailable, depending on whether a buffer was passed in or not.
	* regcache.h (REG_UNAVAILABLE, REG_VALID): New defines.
	(struct regcache): New `register_status' field.
	(supply_register_zeroed): Declare.
	* i387-fp.c (i387_xsave_to_cache): Zero out registers using
	supply_register_zeroed, rather than passing a NULL buffer to
	supply_register.
	* tracepoint.c (fetch_traceframe_registers): Update comment.

1 files changed, 18 insertions, 0 deletions

diff --git a/gdb/gdbserver/regcache.h b/gdb/gdbserver/regcache.h
index df3b261..5fe64cb 100644
--- a/gdb/gdbserver/regcache.h
+++ b/gdb/gdbserver/regcache.h
@@ -23,15 +23,31 @@
 struct inferior_list_entry;
 struct thread_info;
 
+/* The register exists, it has a value, but we don't know what it is.
+   Used when inspecting traceframes.  */
+#define REG_UNAVAILABLE 0
+
+/* We know the register's value (and we have it cached).  */
+#define REG_VALID 1
+
 /* The data for the register cache.  Note that we have one per
    inferior; this is primarily for simplicity, as the performance
    benefit is minimal.  */
 
 struct regcache
 {
+  /* Whether the REGISTERS buffer's contents are valid.  If false, we
+     haven't fetched the registers from the target yet.  Not that this
+     register cache is _not_ pass-through, unlike GDB's.  Note that
+     "valid" here is unrelated to whether the registers are available
+     in a traceframe.  For that, check REGISTER_STATUS below.  */
   int registers_valid;
   int registers_owned;
   unsigned char *registers;
+#ifndef IN_PROCESS_AGENT
+  /* One of REG_UNAVAILBLE or REG_VALID.  */
+  unsigned char *register_status;
+#endif
 };
 
 struct regcache *init_register_cache (struct regcache *regcache,
@@ -84,6 +100,8 @@ extern const char *gdbserver_xmltarget;
 
 void supply_register (struct regcache *regcache, int n, const void *buf);
 
+void supply_register_zeroed (struct regcache *regcache, int n);
+
 void supply_register_by_name (struct regcache *regcache,
 			      const char *name, const void *buf);