Associate target_dcache to address_space.

Hi,
Nowadays, 'target_dcache' is a global variable in GDB, which is not
necessary.  It can be a per-address-space variable.  In this patch, we
associate target_dcache to address_space.

gdb/doc:

2013-11-20  Yao Qi  <yao@codesourcery.com>

	* gdb.texinfo (Caching Target Data): Update doc for
	per-address-space dcache.

gdb:

2013-11-20  Yao Qi  <yao@codesourcery.com>

	* progspace.h (struct address_space_data): Declare.
	* target-dcache.c: Include "progspace.h".
	(target_dache): Remove.
	(target_dcache_aspace_key): New.
	(target_dcache_cleanup): New function.
	(target_dcache_init_p): Get data through
	target_dcache_aspace_key.
	(target_dcache_invalidate): Likewise.
	(target_dcache_get): Likewise.
	(target_dcache_get_or_init): Likewise.
	(_initialize_target_dcache): Initialize
	target_dcache_aspace_key.

gdb/ChangeLog

@@ -1,3 +1,18 @@
+2013-11-20  Yao Qi  <yao@codesourcery.com>
+
+	* progspace.h (struct address_space_data): Declare.
+	* target-dcache.c: Include "progspace.h".
+	(target_dache): Remove.
+	(target_dcache_aspace_key): New.
+	(target_dcache_cleanup): New function.
+	(target_dcache_init_p): Get data through
+	target_dcache_aspace_key.
+	(target_dcache_invalidate): Likewise.
+	(target_dcache_get): Likewise.
+	(target_dcache_get_or_init): Likewise.
+	(_initialize_target_dcache): Initialize
+	target_dcache_aspace_key.
+
 2013-11-20  Yao Qi  <yao@codesourcery.com>
 
 	* progspace.c (struct address_space): Update comments.

gdb/doc/ChangeLog

@@ -1,3 +1,8 @@
+2013-11-20  Yao Qi  <yao@codesourcery.com>
+
+	* gdb.texinfo (Caching Target Data): Update doc for
+	per-address-space dcache.
+
 2013-11-20  Yao Qi  <yao@codesourcery.com>
 
 	* gdb.texinfo (Data): Rename menu item.

gdb/doc/gdb.texinfo

@@ -10828,6 +10828,8 @@ character.
 @cindex caching data of targets
 
 @value{GDBN} caches data exchanged between the debugger and a target.
+Each cache is associated with the address space of the inferior.
+@xref{Inferiors and Programs}, about inferior and address space.
 Such caching generally improves performance in remote debugging
 (@pxref{Remote Debugging}), because it reduces the overhead of the
 remote protocol by bundling memory reads and writes into large chunks.
@@ -10867,11 +10869,11 @@ Show the current state of data caching for memory accesses.
 
 @kindex info dcache
 @item info dcache @r{[}line@r{]}
-Print the information about the data cache performance.  The
-information displayed includes the dcache width and depth, and for
-each cache line, its number, address, and how many times it was
-referenced.  This command is useful for debugging the data cache
-operation.
+Print the information about the performance of data cache of the
+current inferior's address space.  The information displayed
+includes the dcache width and depth, and for each cache line, its
+number, address, and how many times it was referenced.  This
+command is useful for debugging the data cache operation.
 
 If a line number is specified, the contents of that line will be
 printed in hex.

gdb/progspace.h

@@ -33,6 +33,7 @@ struct inferior;
 struct exec;
 struct address_space;
 struct program_space_data;
+struct address_space_data;
 
 typedef struct so_list *so_list_ptr;
 DEF_VEC_P (so_list_ptr);

gdb/target-dcache.c

@@ -18,16 +18,31 @@
 #include "defs.h"
 #include "target-dcache.h"
 #include "gdbcmd.h"
+#include "progspace.h"
 
-/* Cache of memory operations, to speed up remote access.  */
-static DCACHE *target_dcache;
+/* The target dcache is kept per-address-space.  This key lets us
+   associate the cache with the address space.  */
+
+static const struct address_space_data *target_dcache_aspace_key;
+
+/* Clean up dcache, represented by ARG, which is associated with
+   ASPACE.  */
+
+static void
+target_dcache_cleanup (struct address_space *aspace, void *arg)
+{
+  dcache_free (arg);
+}
 
 /* Target dcache is initialized or not.  */
 
 int
 target_dcache_init_p (void)
 {
-  return (target_dcache != NULL);
+  DCACHE *dcache = address_space_data (current_program_space->aspace,
+				       target_dcache_aspace_key);
+
+  return (dcache != NULL);
 }
 
 /* Invalidate the target dcache.  */
@@ -35,8 +50,11 @@ target_dcache_init_p (void)
 void
 target_dcache_invalidate (void)
 {
-  if (target_dcache_init_p ())
-    dcache_invalidate (target_dcache);
+  DCACHE *dcache = address_space_data (current_program_space->aspace,
+				       target_dcache_aspace_key);
+
+  if (dcache != NULL)
+    dcache_invalidate (dcache);
 }
 
 /* Return the target dcache.  Return NULL if target dcache is not
@@ -45,7 +63,10 @@ target_dcache_invalidate (void)
 DCACHE *
 target_dcache_get (void)
 {
-  return target_dcache;
+  DCACHE *dcache = address_space_data (current_program_space->aspace,
+				       target_dcache_aspace_key);
+
+  return dcache;
 }
 
 /* Return the target dcache.  If it is not initialized yet, initialize
@@ -54,10 +75,13 @@ target_dcache_get (void)
 DCACHE *
 target_dcache_get_or_init (void)
 {
-  if (!target_dcache_init_p ())
-    target_dcache = dcache_init ();
+  DCACHE *dcache = address_space_data (current_program_space->aspace,
+				       target_dcache_aspace_key);
 
-  return target_dcache;
+  if (dcache == NULL)
+    dcache = dcache_init ();
+
+  return dcache;
 }
 
 /* The option sets this.  */
@@ -113,4 +137,8 @@ By default, caching for stack access is on."),
 			   set_stack_cache_enabled_p,
 			   show_stack_cache_enabled_p,
 			   &setlist, &showlist);
+
+  target_dcache_aspace_key
+    = register_address_space_data_with_cleanup (NULL,
+						target_dcache_cleanup);
 }