This problem was observed while loading and unloading symbols using
add-symbol-file and remove-symbol-file. When remove-symbol-file
command is invoked, it calls clear_symtab_users that calls
varobj_invalidate
to invalidate variable objects. This function invalidates the varobjs
that are tied to locals and re-create the ones that are defined on
globals. During this re-creation of globals, variable objects are
re-evaluated that can result in new value. But this change is not
recorded
and because of this, -var-update for such modified variable objects
gives empty change list.
Proposed Fix:
=============
GDB has mechanism of marking varobj's updated if they are set via
varobj_set_value operation. This allows any next -var-update to report
this change. Same approach should be used during varobj invalidation.
If value of newly created varobj is different from previous one, mark it
updated so that -var-update can get this change.
Variable object invalidation code is cleaned up to avoid using pointers
whose target has been already freed.
Fix Testing:
===========
This fix has been regression tested on both simulator and real boards.
2014-06-27 Taimoor Mirza <tmirza@codesourcery.com>
Maciej W. Rozycki <macro@codesourcery.com>
gdb/
* varobj.h (varobj_is_valid_p, varobj_set_invalid): New
prototypes.
* varobj.c (varobj_is_valid_p, varobj_set_invalid): New
functions.
(varobj_invalidate_iter): Mark re-created global object updated
if its value is different from previous value.
* objfiles.c (invalidate_objfile_varobj_type_iter): New
function.
(free_objfile): Call it.
---
gdb/objfiles.c | 19 +++++++++++++++++++
gdb/varobj.c | 37 +++++++++++++++++++++++++++++++++++++
gdb/varobj.h | 3 +++
3 files changed, 59 insertions(+)
diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index 0a0b1cb..03559a3 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -32,6 +32,7 @@
#include "bcache.h"
#include "expression.h"
#include "parser-defs.h"
+#include "varobj.h"
#include "gdb_assert.h"
#include <sys/types.h>
@@ -538,6 +539,21 @@ free_objfile_separate_debug (struct objfile
*objfile)
}
}
+/* Mark the variable object VAR invalid if built upon a type coming from
+ the objfile requested, passed as DATA. Also clear the type
reference. */
+
+static void
+invalidate_objfile_varobj_type_iter (struct varobj *var, void *data)
+{
+ struct objfile *objfile = data;
+
+ if (varobj_is_valid_p (var) && TYPE_OBJFILE (var->type) == objfile)
+ {
+ varobj_set_invalid (var);
+ var->type = NULL;
+ }
+}
+
/* Destroy an objfile and all the symtabs and psymtabs under it. */
void
@@ -584,6 +600,9 @@ free_objfile (struct objfile *objfile)
lists. */
preserve_values (objfile);
+ /* Varobj may refer to types stored in objfile's obstack. */
+ all_root_varobjs (invalidate_objfile_varobj_type_iter, objfile);
+
/* It still may reference data modules have associated with the
objfile and
the symbol file data. */
forget_cached_source_info_for_objfile (objfile);
diff --git a/gdb/varobj.c b/gdb/varobj.c
index 7446f10..2a563af 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -2683,6 +2683,22 @@ varobj_floating_p (struct varobj *var)
return var->root->floating;
}
+/* Get the valid flag of varobj VAR. */
+
+int
+varobj_is_valid_p (struct varobj *var)
+{
+ return var->root->is_valid;
+}
+
+/* Clear the valid flag on varobj VAR. */
+
+void
+varobj_set_invalid (struct varobj *var)
+{
+ var->root->is_valid = 0;
+}
+
/* Implement the "value_is_changeable_p" varobj callback for most
languages. */
@@ -2762,6 +2778,7 @@ varobj_invalidate_iter (struct varobj *var, void
*unused)
if (var->root->floating || var->root->valid_block == NULL)
{
struct varobj *tmp_var;
+ char *tmp_var_value, *var_value;
/* Try to create a varobj with same expression. If we succeed
replace the old varobj, otherwise invalidate it. */
@@ -2770,6 +2787,26 @@ varobj_invalidate_iter (struct varobj *var,
void *unused)
if (tmp_var != NULL)
{
tmp_var->obj_name = xstrdup (var->obj_name);
+ tmp_var_value = varobj_get_value (tmp_var);
+ var_value = varobj_get_value (var);
+
+ /* As varobjs are re-evaluated during creation so there is a
+ chance that new value is different from old one. Compare
+ value of old varobj and newly created varobj and mark
+ varobj updated If new value is different. */
+ if (var_value == NULL && tmp_var_value == NULL)
+ ; /* Equal. */
+ else if (var_value == NULL || tmp_var_value == NULL)
+ tmp_var->updated = 1;
+ else
+ {
+ /* Mark tmp_var updated if new value is different. */
+ if (strcmp (tmp_var_value, var_value) != 0)
+ tmp_var->updated = 1;
+ }
+
+ xfree (tmp_var_value);
+ xfree (var_value);
varobj_delete (var, NULL, 0);
install_variable (tmp_var);
}
diff --git a/gdb/varobj.h b/gdb/varobj.h
index 74d41cf..7439a94 100644
--- a/gdb/varobj.h
+++ b/gdb/varobj.h
@@ -299,6 +299,9 @@ extern int varobj_editable_p (struct varobj *var);
extern int varobj_floating_p (struct varobj *var);
+extern int varobj_is_valid_p (struct varobj *var);
+extern void varobj_set_invalid (struct varobj *var);
+
extern void varobj_set_visualizer (struct varobj *var,
const char *visualizer);