[PATCH v2 1/2] thread: add can_access_registers_ptid

Markus Metzger
2017-01-20T14:39:13Z

Add a function can_access_registers_ptid that behaves like
validate_registers_access but returns a boolean value instead of throwing an
exception.

2017-01-20 Markus Metzger <markus.t.metzger@intel.com>

* gdbthread.h (can_access_registers_ptid): New.
* thread.c (can_access_registers_ptid): New.
---
gdb/gdbthread.h | 4 ++++
gdb/thread.c | 20 ++++++++++++++++++++
2 files changed, 24 insertions(+)

diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h
index 455cfd8..041b7c2 100644
--- a/gdb/gdbthread.h
+++ b/gdb/gdbthread.h
@@ -625,6 +625,10 @@ extern void thread_cancel_execution_command (struct thread_info *thr);
executing). */
extern void validate_registers_access (void);

+/* Check whether it makes sense to access a register of PTID at this point.
+ Returns non-zero if registers may be accessed; zero otherwise. */
+extern int can_access_registers_ptid (ptid_t ptid);
+
/* Returns whether to show which thread hit the breakpoint, received a
signal, etc. and ended up causing a user-visible stop. This is
true iff we ever detected multiple threads. */
diff --git a/gdb/thread.c b/gdb/thread.c
index e45b257..d5dfe80 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -1141,6 +1141,26 @@ validate_registers_access (void)
error (_("Selected thread is running."));
}

+/* See gdbthread.h. */
+
+int
+can_access_registers_ptid (ptid_t ptid)
+{
+ /* No thread, no registers. */
+ if (ptid_equal (ptid, null_ptid))
+ return 0;
+
+ /* Don't try to read from a dead thread. */
+ if (is_exited (ptid))
+ return 0;
+
+ /* ... or from a spinning thread. FIXME: see validate_registers_access. */
+ if (is_executing (ptid))
+ return 0;
+
+ return 1;
+}
+
int
pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread)
{
--
1.8.3.1