gdb: Fix regression in varobj recreation
Commit bc20e562ec0 "Fix use after free in varobj" introduced a
regression. This commit makes sure that the varobj object does not
keeps stale references to object being freed when we unload an objfile.
This includes the "valid_block" field which is reset to nullptr if the
pointed to block is tied to an objfile being freed.
However, at some point varobj_invalidate_iter might try to recreate
varobjs tracking either floating or globals. Varobj tracking globals
are identified as having the "valid_block" field set nullptr, but as
bc20e562ec0 might clear this field, we have lost the ability to
distinguish between varobj referring to globals and non globals.
Fix this by introducing a "global" flag which tracks if a given varobj
was initially created as tracking a global.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29426
diff --git a/gdb/varobj.c b/gdb/varobj.c
index e558794..0683af1 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -102,6 +102,9 @@
to symbols that do not exist anymore. */
bool is_valid = true;
+ /* Set to true if the varobj was created as tracking a global. */
+ bool global = false;
+
/* Language-related operations for this variable and its
children. */
const struct lang_varobj_ops *lang_ops = NULL;
@@ -336,6 +339,8 @@
var->format = variable_default_display (var.get ());
var->root->valid_block =
var->root->floating ? NULL : tracker.block ();
+ var->root->global
+ = var->root->floating ? false : var->root->valid_block == nullptr;
var->name = expression;
/* For a root var, the name and the expr are the same. */
var->path_expr = expression;
@@ -2359,7 +2364,7 @@
varobj_invalidate_iter (struct varobj *var)
{
/* global and floating var must be re-evaluated. */
- if (var->root->floating || var->root->valid_block == nullptr)
+ if (var->root->floating || var->root->global)
{
struct varobj *tmp_var;
@@ -2375,7 +2380,7 @@
varobj_delete (var, 0);
install_variable (tmp_var);
}
- else if (!var->root->floating)
+ else if (var->root->global)
{
/* Only invalidate globals as floating vars might still be valid in
some other frame. */
