[PATCH 07/10] Associate target_dcache to address_space.

Yao Qi
2013-11-03T05:56:06Z

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:

2013-11-02 Yao Qi <yao@codesourcery.com>

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

gdb:

2013-11-02 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/doc/gdb.texinfo | 12 ++++++----
gdb/progspace.h | 1 +
gdb/target-dcache.c | 60 +++++++++++++++++++++++++++++++++++++-------------
3 files changed, 52 insertions(+), 21 deletions(-)

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 561243b..a64bb0b 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -10813,6 +10813,8 @@ 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. See
+@ref{Inferiors and Programs} about inferior and address space.
Such caching generally improves performance in @ref{Remote Debugging},
because it reduces the overhead of the remote protocol by
bundling memory reads and writes into large chunks. Unfortunately, simply
@@ -10851,11 +10853,11 @@ 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.
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-dcache.c b/gdb/target-dcache.c
index 28f1aa6..a840c40 100644
--- a/gdb/target-dcache.c
+++ b/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
@@ -45,15 +63,18 @@ target_dcache_invalidate (void)
DCACHE *
target_dcache_get (void)
{
- if (target_dcache_init_p ())
+ DCACHE *dcache = address_space_data (current_program_space->aspace,
+ target_dcache_aspace_key);
+
+ if (dcache != NULL)
{
- if (dcache_invalidate_p (target_dcache))
- dcache_invalidate (target_dcache);
+ if (dcache_invalidate_p (dcache))
+ dcache_invalidate (dcache);

- dcache_shrink (target_dcache);
+ dcache_shrink (dcache);
}

- return target_dcache;
+ return dcache;
}

/* Return the target dcache. If it is not initialized yet, initialize
@@ -62,17 +83,20 @@ target_dcache_get (void)
DCACHE *
target_dcache_get_or_init (void)
{
- if (target_dcache_init_p ())
+ DCACHE *dcache = address_space_data (current_program_space->aspace,
+ target_dcache_aspace_key);
+
+ if (dcache != NULL)
{
- if (dcache_invalidate_p (target_dcache))
- dcache_invalidate (target_dcache);
+ if (dcache_invalidate_p (dcache))
+ dcache_invalidate (dcache);

- dcache_shrink (target_dcache);
+ dcache_shrink (dcache);
}
else
- target_dcache = dcache_init ();
+ dcache = dcache_init ();

- return target_dcache;
+ return dcache;
}

/* The option sets this. */
@@ -128,4 +152,8 @@ 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);
}
--
1.7.7.6