[PATCH 3/3] gdb/testsuite: Handle targets with lots of registers

[Andrew Burgess <andrew.burgess@embecosm.com>]

In gdb.base/maint.exp a test calls 'maint print registers'.  If the
target has lots of registers this may overflow expect's buffers,
causing the test to fail.

After this commit we process the output line at a time until we get back
to the GDB prompt, this should prevent buffer overrun while still
testing that the command works as required.

gdb/testsuite/ChangeLog:

	* gdb.base/maint.exp: Process output from 'maint print registers'
	line at a time.
---
 gdb/testsuite/ChangeLog          |  5 +++++
 gdb/testsuite/gdb.base/maint.exp | 18 ++++++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/gdb/testsuite/gdb.base/maint.exp b/gdb/testsuite/gdb.base/maint.exp
index 93221085653..f73495faa5b 100644
--- a/gdb/testsuite/gdb.base/maint.exp
+++ b/gdb/testsuite/gdb.base/maint.exp
@@ -62,8 +62,22 @@ gdb_test_no_output "set height 0"
 gdb_file_cmd ${binfile}
 
 # Test for a regression where this command would internal-error if the
-# program wasn't running.
-gdb_test "maint print registers" "Name.*Nr.*Rel.*Offset.*Size.*Type.*"
+# program wasn't running.  If there's a lot of registers then this
+# might overflow expect's buffers, so process the output line at a
+# time.
+send_gdb "maint print registers\n"
+gdb_expect {
+    -re "^\[^\n\r\]+\[0-9\]+\[^\n\r\]+\[0-9\]+\[^\n\r\]+\[0-9\]+\[^\n\r\]+\[0-9\]+\[^\n\r\]+\[\n\r\]+" {
+	exp_continue
+    }
+    -re ".*$gdb_prompt $" {
+	pass "maint print registers"
+    }
+    timeout {
+	fail "maint print registers (timeout)"
+    }
+}
+
 
 # Test "mt expand-symtabs" here as it's easier to verify before we
 # run the program.
-- 
2.12.2