http://sourceware.org/ml/gdb-patches/2012-07/msg00551.html

Re-evaluate floating variables as part of variable invalidate to remove
references to type structures that might have been freed.

4 files changed, 27 insertions, 8 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a89362b..4e83c25 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2012-07-30  Andrew Burgess  <aburgess@broadcom.com>
+
+	* varobj.c (varobj_invalidate_iter): All varobj must be marked as
+	invalid or reevaluated to prevent prevent references to possibly
+	delete'd type objects being left in the varobj.
+
 2012-07-27  Tom Tromey  <tromey@redhat.com>
 	    Jan Kratochvil  <jan.kratochvil@redhat.com>
 
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 137c2e7..42ae5c8 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-07-30  Andrew Burgess  <aburgess@broadcom.com>
+
+	* gdb.mi/mi-var-invalidate.exp: Create a floating variable and
+	change its format immediately after reloading the binary.
+
 2012-07-27  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	Fix testsuite regression after --use-deprecated-index-sections removal.
diff --git a/gdb/testsuite/gdb.mi/mi-var-invalidate.exp b/gdb/testsuite/gdb.mi/mi-var-invalidate.exp
index 3ecbbdf..1f16f88 100644
--- a/gdb/testsuite/gdb.mi/mi-var-invalidate.exp
+++ b/gdb/testsuite/gdb.mi/mi-var-invalidate.exp
@@ -61,6 +61,9 @@ mi_runto do_locals_tests
 # Desc: create local variables
 mi_create_varobj linteger linteger "create local variable linteger"
 
+# Desc: create floating variable
+mi_create_floating_varobj float_simple array "create floating variable"
+
 #
 # Reload the same binary.
 # Global variable should remain, local should be invalidated.
@@ -69,6 +72,12 @@ mi_delete_breakpoints
 mi_gdb_load ${binfile_bis}
 mi_runto main
 
+# Change format of floating variable immediately after reload reveals a
+# bug where gdb still uses a free'd pointer.
+mi_gdb_test "-var-set-format float_simple hexadecimal" \
+        "\\^done,format=\"hexadecimal\",value=\"\\\[-1\\\]\"" \
+       "set format variable float_simple"
+
 # Check local variable is "invalid".
 mi_gdb_test "-var-update linteger" \
 	"\\^done,changelist=\\\[\{name=\"linteger\",in_scope=\"invalid\",has_more=\"0\"\}\\\]" \
diff --git a/gdb/varobj.c b/gdb/varobj.c
index 99b158e..a75a40d 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -4186,18 +4186,17 @@ _initialize_varobj (void)
 }
 
 /* Invalidate varobj VAR if it is tied to locals and re-create it if it is
-   defined on globals.  It is a helper for varobj_invalidate.  */
+   defined on globals.  It is a helper for varobj_invalidate.
+
+   This function is called after changing the symbol file, in this case the
+   pointers to "struct type" stored by the varobj are no longer valid.  All
+   varobj must be either re-evaluated, or marked as invalid here.  */
 
 static void
 varobj_invalidate_iter (struct varobj *var, void *unused)
 {
-  /* Floating varobjs are reparsed on each stop, so we don't care if the
-     presently parsed expression refers to something that's gone.  */
-  if (var->root->floating)
-    return;
-
-  /* global var must be re-evaluated.  */     
-  if (var->root->valid_block == NULL)
+  /* global and floating var must be re-evaluated.  */
+  if (var->root->floating || var->root->valid_block == NULL)
     {
       struct varobj *tmp_var;