Re: [PATCH 2/5] Associate target_dcache to address_space.

[Yao Qi <yao@codesourcery.com>]

On 10/24/2013 12:37 AM, Tom Tromey wrote:
> I like this patch quite a bit.  For one thing, it fixes the target
> dcache for the coming multi-target work:-)
> 
> Yao> +/* The current added space.  */
> Yao> +#define current_address_space current_program_space->aspace
> 
> On the whole I would prefer we not add new object-style macros like
> this.  (Actually I'd really like it if we got rid of the existing ones
> too...)  Writing out the expansion in the few places it is used seems
> better to me.
> 

This macro is removed in the updated patch.

> Yao> +static void
> Yao> +target_dcache_cleanup (struct address_space *aspace, void *arg)
> Yao> +{
> Yao> +  struct target_dcache *dcache
> Yao> +    = address_space_data (aspace, target_dcache_aspace_key);
> Yao> +
> Yao> +  target_dcache_xfree (dcache);
> 
> Here you don't need to call address_space_data, since ARG is the dcache
> that was passed in.

You are right.  Fixed.  b.t.w, this sort of problems exist somewhere
else in the tree, I'll post a patch to fix them separately.

-- 
Yao (齐尧)

gdb:

2013-10-24  Yao Qi  <yao@codesourcery.com>

	* progspace.h (struct address_space): Declare.
	* target.c (target_dcache_aspace_key): New.
	(target_dcache): Delete.
	(struct target_dcache): New.
	(target_dcache_alloc): New function.
	(target_dcache_xfree): New function.
	(target_dcache_get): New function.
	(target_dcache_cleanup)): New function.
	(target_dcache_invalidate): Update.
	(memory_xfer_partial_1): Update.
	(initialize_targets): Initialize target_dcache_aspace_key.
---
 gdb/progspace.h |    1 +
 gdb/target.c    |   87 ++++++++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 77 insertions(+), 11 deletions(-)

diff --git a/gdb/progspace.h b/gdb/progspace.h
index 3735202..bbe81a4 100644
--- a/gdb/progspace.h
+++ b/gdb/progspace.h
@@ -32,6 +32,7 @@ struct objfile;
 struct inferior;
 struct exec;
 struct program_space_data;
+struct address_space_data;
 
 typedef struct so_list *so_list_ptr;
 DEF_VEC_P (so_list_ptr);
diff --git a/gdb/target.c b/gdb/target.c
index 22d7fb6..073a602 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -206,6 +206,70 @@ show_targetdebug (struct ui_file *file, int from_tty,
 
 static void setup_target_debug (void);
 
+/* 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;
+
+/* dcache for target memory.  */
+
+struct target_dcache
+{
+  /* Cache the memory on stack and areas specified by memory
+     attributes.  */
+  DCACHE *general;
+};
+
+/* Allocate an instance of struct target_dcache.  */
+
+static struct target_dcache *
+target_dcache_alloc (void)
+{
+  struct target_dcache *dcache = xmalloc (sizeof (*dcache));
+
+  dcache->general = dcache_init ();
+
+  return dcache;
+}
+
+/* Free DCACHE and its fields.  */
+
+static void
+target_dcache_xfree (struct target_dcache *dcache)
+{
+  if (dcache != NULL)
+    {
+      dcache_free (dcache->general);
+      xfree (dcache);
+    }
+}
+
+/* Get an instance of struct target_dcache.  */
+
+static struct target_dcache *
+target_dcache_get (void)
+{
+  struct target_dcache *dcache
+    = address_space_data (current_program_space->aspace,
+			  target_dcache_aspace_key);
+
+  if (dcache == NULL)
+    {
+      dcache = target_dcache_alloc ();
+
+      set_address_space_data (current_program_space->aspace,
+			      target_dcache_aspace_key, dcache);
+    }
+
+  return dcache;
+}
+
+static void
+target_dcache_cleanup (struct address_space *aspace, void *arg)
+{
+  target_dcache_xfree (arg);
+}
+
 /* The option sets this.  */
 static int stack_cache_enabled_p_1 = 1;
 /* And set_stack_cache_enabled_p updates this.
@@ -235,15 +299,14 @@ show_stack_cache_enabled_p (struct ui_file *file, int from_tty,
   fprintf_filtered (file, _("Cache use for stack accesses is %s.\n"), value);
 }
 
-/* Cache of memory operations, to speed up remote access.  */
-static DCACHE *target_dcache;
-
 /* Invalidate the target dcache.  */
 
 void
 target_dcache_invalidate (void)
 {
-  dcache_invalidate (target_dcache);
+  struct target_dcache *td = target_dcache_get ();
+
+  dcache_invalidate (td->general);
 }
 
 /* The user just typed 'target' without the name of a target.  */
@@ -1589,14 +1652,14 @@ memory_xfer_partial_1 (struct target_ops *ops, enum target_object object,
 	  || (stack_cache_enabled_p && object == TARGET_OBJECT_STACK_MEMORY)))
     {
       if (readbuf != NULL)
-	res = dcache_xfer_memory (ops, target_dcache, memaddr, readbuf,
-				  reg_len, 0);
+	res = dcache_xfer_memory (ops, target_dcache_get ()->general,
+				  memaddr, readbuf, reg_len, 0);
       else
 	/* FIXME drow/2006-08-09: If we're going to preserve const
 	   correctness dcache_xfer_memory should take readbuf and
 	   writebuf.  */
-	res = dcache_xfer_memory (ops, target_dcache, memaddr,
-				  (void *) writebuf,
+	res = dcache_xfer_memory (ops, target_dcache_get ()->general,
+				  memaddr, (void *) writebuf,
 				  reg_len, 1);
       if (res <= 0)
 	return -1;
@@ -1641,7 +1704,8 @@ memory_xfer_partial_1 (struct target_ops *ops, enum target_object object,
       && stack_cache_enabled_p
       && object != TARGET_OBJECT_STACK_MEMORY)
     {
-      dcache_update (target_dcache, memaddr, (void *) writebuf, res);
+      dcache_update (target_dcache_get ()->general, memaddr,
+		     (void *) writebuf, res);
     }
 
   /* If we still haven't got anything, return the last error.  We
@@ -5187,6 +5251,7 @@ Otherwise, any attempt to interrupt or stop will be ignored."),
 			   set_target_permissions, NULL,
 			   &setlist, &showlist);
 
-
-  target_dcache = dcache_init ();
+  target_dcache_aspace_key
+    = register_address_space_data_with_cleanup (NULL,
+						target_dcache_cleanup);
 }
-- 
1.7.7.6