[PATCH 2/3] gdb/regcache: return REG_UNAVAILABLE if raw_update raises NOT_AVAILABLE_ERROR

[Tankut Baris Aktemur]

In regcache's raw_read, it is possible that 'raw_update' fails with an
exception.  Catch this exception and return REG_UNAVAILABLE if the
error is of kind NOT_AVAILABLE_ERROR.  This makes clients' lives easier.

Regression-tested on X86_64-Linux.

gdb/ChangeLog:
2020-11-13  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* regcache.c (readable_regcache::raw_read): Return REG_UNAVAILABLE
	if raw_update raises NOT_AVAILABLE_ERROR.
---
 gdb/regcache.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/gdb/regcache.c b/gdb/regcache.c
index 91d3202b94b..0b2373b15db 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -594,7 +594,16 @@ enum register_status
 readable_regcache::raw_read (int regnum, gdb_byte *buf)
 {
   gdb_assert (buf != NULL);
-  raw_update (regnum);
+  try
+    {
+      raw_update (regnum);
+    }
+  catch (const gdb_exception_error &ex)
+    {
+      if (ex.error == NOT_AVAILABLE_ERROR)
+	return REG_UNAVAILABLE;
+      throw;
+    }
 
   if (m_register_status[regnum] != REG_VALID)
     memset (buf, 0, m_descr->sizeof_register[regnum]);
-- 
2.17.1