[PATCH 1/2] watchpoint-reuse-slot.exp: skip some tests on targets have different wp and bp registers

[Yao Qi <qiyaoltc@gmail.com>]

From: Yao Qi <yao.qi@linaro.org>

watchpoint-reuse-slot.exp sets two hardware breakpoint and/or watchpoint,
to test the same debugging register can be used correctly.  However,
on some targets, such as arm and aarch64, hardware has different
registers for breakpoint and watchpoint, so don't have to do test
if one breakpoint and one watchpoint are requested and target hardware
has different debugging registers for breakpoint and watchpoint.

gdb/testsuite:

2015-03-13  Yao Qi  <yao.qi@linaro.org>

	* gdb.base/watchpoint-reuse-slot.exp (dbg_registers_for_watch_and_break):
	New proc.
	(top level): Skip tests if breakpoint and watchpoint are
	requested and dbg_registers_for_watch_and_break returns false.
---
 gdb/testsuite/gdb.base/watchpoint-reuse-slot.exp | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/gdb/testsuite/gdb.base/watchpoint-reuse-slot.exp b/gdb/testsuite/gdb.base/watchpoint-reuse-slot.exp
index 844bf3a..df6eeb6 100644
--- a/gdb/testsuite/gdb.base/watchpoint-reuse-slot.exp
+++ b/gdb/testsuite/gdb.base/watchpoint-reuse-slot.exp
@@ -157,6 +157,19 @@ proc watch_command {cmd base offset width} {
     }
 }
 
+# Return true if the same debugging register can be used for both
+# watchpoint and breakpoint.
+
+proc dbg_registers_for_watch_and_break {} {
+    if { [istarget "arm*-linux*"] || [istarget "aarch64*-*-linux*"] } {
+	# arm and aarch64 has different registers for watchpoint and
+	# breakpoint.
+	return 0
+    }
+
+    return 1
+}
+
 # Run test proper.  See intro for description.
 
 foreach always_inserted {"off" "on" } {
@@ -171,6 +184,16 @@ foreach always_inserted {"off" "on" } {
 		    continue
 		}
 
+		if {($cmd1 == "hbreak" && $cmd2 != "hbreak"
+		     || $cmd1 != "hbreak" && $cmd2 == "hbreak")
+		    && ![dbg_registers_for_watch_and_break]} {
+		    # One breakpoint and watchpoint is requested, but
+		    # different registers are used for breakpoint and
+		    # watchpoint, then, the same slot can't be reused.
+		    # Skip it.
+		    continue
+		}
+
 		for {set x 0} {$x < 4} {incr x} {
 		    set prefix "always-inserted $always_inserted: "
 		    append prefix "$cmd1 x $cmd2: "
-- 
1.9.1