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authorDoug Evans <dje@google.com>2009-08-31 20:18:46 +0000
committerDoug Evans <dje@google.com>2009-08-31 20:18:46 +0000
commit4e5d721fc0b3a9de5764a7b3bf3d6be4132ab67b (patch)
tree1818952fb05548383ecc47eded2a17631aff6ca0 /gdb/dcache.c
parentf1c2d4afbe03f4303f200ba418a446da410cba17 (diff)
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Implement TARGET_OBJECT_STACK_MEMORY.
* NEWS: Add note on new "set stack-cache" option. * corefile.c (read_stack): New function. * dcache.c (dcache_struct): New member ptid. (dcache_enable_p): Mark as obsolete. (show_dcache_enabled_p): Flag option as deprecated. (dcache_invalidate): Update ptid. (dcache_invalidate_line): New function. (dcache_read_line): No longer check cacheable attribute, stack accesses get cached despite attribute. (dcache_init): Set ptid. (dcache_xfer_memory): Flush cache if from different ptid than before. Update cache after write. (dcache_update): New function. (dcache_info): Report ptid. (_initialize_dcache): Update text for `remotecache' to indicate it is obsolete. * dcache.h (dcache_update): Declare. * dwarf2loc.c (dwarf2_evaluate_loc_desc): Mark values on stack with set_value_stack. * frame-unwind.c (frame_unwind_got_memory): Ditto. * gdbcore.h (read_stack): Declare. * memattr.c (mem_enable_command): Call target_dcache_invalidate instead of dcache_invalidate. (mem_disable_command, mem_delete_command): Ditto. * target.c (stack_cache_enabled_p_1): New static global. (stack_cache_enabled_p): New static global. (set_stack_cache_enabled_p): New function. (show_stack_cache_enabled_p): New function. (target_dcache): Make static. (target_dcache_invalidate): New function. (target_load, target_resume): Call target_dcache_invalidate instead of dcache_invalidate. (memory_xfer_partial): New arg object, all callers updated. Check for existing inferior before calling dcache routines. When writing non-TARGET_OBJECT_STACK_MEMORY, notify dcache. (target_xfer_partial): Call memory_xfer_partial for TARGET_OBJECT_STACK_MEMORY. (target_read_stack): New function. (initialize_targets): Install new option `stack-cache'. * target.h: Remove #include of dcache.h. (enum target_object): New value TARGET_OBJECT_STACK_MEMORY. (target_dcache): Delete. (target_dcache_invalidate): Declare. (target_read_stack): Declare. * top.c (prepare_execute_command): New function. (execute_command): Call prepare_execute_command instead of free_all_values. * top.h (prepare_execute_command): Declare. * valops.c (get_value_at): New function. (value_at): Guts moved to get_value_at. (value_at_lazy): Similarly. (value_fetch_lazy): Call read_stack for stack values. * value.c (struct value): New member `stack'. (value_stack, set_value_stack): New functions. * value.h (value_stack, set_value_stack): Declare. * mi/mi-main.c (mi_cmd_execute): Call prepare_execute_command instead of free_all_values. doc/ * gdb.texinfo (Caching Data of Remote Targets): Update text. Mark `set/show remotecache' options as obsolete. Document new `set/show stack-cache' option. Update text for `info dcache'.
Diffstat (limited to 'gdb/dcache.c')
-rw-r--r--gdb/dcache.c88
1 files changed, 72 insertions, 16 deletions
diff --git a/gdb/dcache.c b/gdb/dcache.c
index 17c948a..52375f0 100644
--- a/gdb/dcache.c
+++ b/gdb/dcache.c
@@ -24,6 +24,7 @@
#include "gdb_string.h"
#include "gdbcore.h"
#include "target.h"
+#include "inferior.h"
#include "splay-tree.h"
/* The data cache could lead to incorrect results because it doesn't
@@ -103,6 +104,9 @@ struct dcache_struct
/* The number of in-use lines in the cache. */
int size;
+
+ /* The ptid of last inferior to use cache or null_ptid. */
+ ptid_t ptid;
};
static struct dcache_block *dcache_hit (DCACHE *dcache, CORE_ADDR addr);
@@ -117,16 +121,15 @@ static void dcache_info (char *exp, int tty);
void _initialize_dcache (void);
-static int dcache_enabled_p = 0;
+static int dcache_enabled_p = 0; /* OBSOLETE */
static void
show_dcache_enabled_p (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
- fprintf_filtered (file, _("Cache use for remote targets is %s.\n"), value);
+ fprintf_filtered (file, _("Deprecated remotecache flag is %s.\n"), value);
}
-
static DCACHE *last_cache; /* Used by info dcache */
/* Free all the data cache blocks, thus discarding all cached data. */
@@ -152,6 +155,23 @@ dcache_invalidate (DCACHE *dcache)
dcache->oldest = NULL;
dcache->newest = NULL;
dcache->size = 0;
+ dcache->ptid = null_ptid;
+}
+
+/* Invalidate the line associated with ADDR. */
+
+static void
+dcache_invalidate_line (DCACHE *dcache, CORE_ADDR addr)
+{
+ struct dcache_block *db = dcache_hit (dcache, addr);
+
+ if (db)
+ {
+ splay_tree_remove (dcache->tree, (splay_tree_key) db->addr);
+ db->newer = dcache->freelist;
+ dcache->freelist = db;
+ --dcache->size;
+ }
}
/* If addr is present in the dcache, return the address of the block
@@ -198,8 +218,9 @@ dcache_read_line (DCACHE *dcache, struct dcache_block *db)
else
reg_len = region->hi - memaddr;
- /* Skip non-cacheable/non-readable regions. */
- if (!region->attrib.cache || region->attrib.mode == MEM_WO)
+ /* Skip non-readable regions. The cache attribute can be ignored,
+ since we may be loading this for a stack access. */
+ if (region->attrib.mode == MEM_WO)
{
memaddr += reg_len;
myaddr += reg_len;
@@ -296,7 +317,7 @@ dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr)
an area of memory which wasn't present in the cache doesn't cause
it to be loaded in.
- Always return 1 to simplify dcache_xfer_memory. */
+ Always return 1 (meaning success) to simplify dcache_xfer_memory. */
static int
dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr)
@@ -338,6 +359,7 @@ dcache_init (void)
dcache->newest = NULL;
dcache->freelist = NULL;
dcache->size = 0;
+ dcache->ptid = null_ptid;
last_cache = dcache;
return dcache;
@@ -366,7 +388,7 @@ dcache_free (DCACHE *dcache)
to or from debugger address MYADDR. Write to inferior if SHOULD_WRITE is
nonzero.
- Returns length of data written or read; 0 for error. */
+ The meaning of the result is the same as for target_write. */
int
dcache_xfer_memory (struct target_ops *ops, DCACHE *dcache,
@@ -378,6 +400,15 @@ dcache_xfer_memory (struct target_ops *ops, DCACHE *dcache,
int (*xfunc) (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr);
xfunc = should_write ? dcache_poke_byte : dcache_peek_byte;
+ /* If this is a different inferior from what we've recorded,
+ flush the cache. */
+
+ if (! ptid_equal (inferior_ptid, dcache->ptid))
+ {
+ dcache_invalidate (dcache);
+ dcache->ptid = inferior_ptid;
+ }
+
/* Do write-through first, so that if it fails, we don't write to
the cache at all. */
@@ -385,14 +416,25 @@ dcache_xfer_memory (struct target_ops *ops, DCACHE *dcache,
{
res = target_write (ops, TARGET_OBJECT_RAW_MEMORY,
NULL, myaddr, memaddr, len);
- if (res < len)
- return 0;
+ if (res <= 0)
+ return res;
+ /* Update LEN to what was actually written. */
+ len = res;
}
for (i = 0; i < len; i++)
{
if (!xfunc (dcache, memaddr + i, myaddr + i))
- return 0;
+ {
+ /* That failed. Discard its cache line so we don't have a
+ partially read line. */
+ dcache_invalidate_line (dcache, memaddr + i);
+ /* If we're writing, we still wrote LEN bytes. */
+ if (should_write)
+ return len;
+ else
+ return i;
+ }
}
return len;
@@ -407,6 +449,18 @@ dcache_xfer_memory (struct target_ops *ops, DCACHE *dcache,
"logically" connected but not actually a single call to one of the
memory transfer functions. */
+/* Just update any cache lines which are already present. This is called
+ by memory_xfer_partial in cases where the access would otherwise not go
+ through the cache. */
+
+void
+dcache_update (DCACHE *dcache, CORE_ADDR memaddr, gdb_byte *myaddr, int len)
+{
+ int i;
+ for (i = 0; i < len; i++)
+ dcache_poke_byte (dcache, memaddr + i, myaddr + i);
+}
+
static void
dcache_print_line (int index)
{
@@ -474,12 +528,15 @@ dcache_info (char *exp, int tty)
printf_filtered (_("Dcache line width %d, maximum size %d\n"),
LINE_SIZE, DCACHE_SIZE);
- if (!last_cache)
+ if (!last_cache || ptid_equal (last_cache->ptid, null_ptid))
{
printf_filtered (_("No data cache available.\n"));
return;
}
+ printf_filtered (_("Contains data for %s\n"),
+ target_pid_to_str (last_cache->ptid));
+
refcount = 0;
n = splay_tree_min (last_cache->tree);
@@ -507,11 +564,10 @@ _initialize_dcache (void)
&dcache_enabled_p, _("\
Set cache use for remote targets."), _("\
Show cache use for remote targets."), _("\
-When on, use data caching for remote targets. For many remote targets\n\
-this option can offer better throughput for reading target memory.\n\
-Unfortunately, gdb does not currently know anything about volatile\n\
-registers and thus data caching will produce incorrect results with\n\
-volatile registers are in use. By default, this option is off."),
+This used to enable the data cache for remote targets. The cache\n\
+functionality is now controlled by the memory region system and the\n\
+\"stack-cache\" flag; \"remotecache\" now does nothing and\n\
+exists only for compatibility reasons."),
NULL,
show_dcache_enabled_p,
&setlist, &showlist);