[python][patch] Return hash value for gdb.Value.

[Phil Muldoon <pmuldoon@redhat.com>]

This patch implements the hash function for gdb.Value. It purely replicates
the function of id() in that it returns the object address as the hash
value. This allows gdb.Values to be hashable.

Ok?

Cheers,

Phil

--

ChangeLogs


2010-05-13  Phil Muldoon  <pmuldoon@redhat.com>

	* gdb.python/py-value.exp (test_value_hash): New function.

2010-05-13  Phil Muldoon  <pmuldoon@redhat.com>

	PR python/11482

	* python/py-value.c (valpy_hash): New function.
	(value_object_type): Register valpy_hash.

---

diff --git a/gdb/python/py-value.c b/gdb/python/py-value.c
index 173b3c9..2a7f76b 100644
--- a/gdb/python/py-value.c
+++ b/gdb/python/py-value.c
@@ -432,6 +432,13 @@ valpy_get_is_optimized_out (PyObject *self, void *closure)
   Py_RETURN_FALSE;
 }
 
+/* Calculate and return the address of the PyObject as the value of
+   the builtin __hash__ call.  */
+long valpy_hash (PyObject *self)
+{
+  return (long) (intptr_t) self;
+}
+
 enum valpy_opcode
 {
   VALPY_ADD,
@@ -1097,7 +1104,7 @@ PyTypeObject value_object_type = {
   &value_object_as_number,	  /*tp_as_number*/
   0,				  /*tp_as_sequence*/
   &value_object_as_mapping,	  /*tp_as_mapping*/
-  0,				  /*tp_hash */
+  valpy_hash,		          /*tp_hash*/
   0,				  /*tp_call*/
   valpy_str,			  /*tp_str*/
   0,				  /*tp_getattro*/
diff --git a/gdb/testsuite/gdb.python/py-value.exp b/gdb/testsuite/gdb.python/py-value.exp
index 3bfa173..67a2ff9 100644
--- a/gdb/testsuite/gdb.python/py-value.exp
+++ b/gdb/testsuite/gdb.python/py-value.exp
@@ -393,6 +393,23 @@ proc test_parse_and_eval {} {
     "parse_and_eval type test"
 }
 
+# Test that values are hashable.
+proc test_value_hash {} {
+  gdb_py_test_multiple "Simple Python value dictionary" \
+    "python" "" \
+    "one = gdb.Value(1)" "" \
+    "two = gdb.Value(2)" "" \
+    "three = gdb.Value(3)" "" \
+    "vdict = {one:\"one str\",two:\"two str\",three:\"three str\"}" "" \
+    "end"
+    gdb_test "python print vdict\[one\]" "one str" "Test dictionary hash"
+    gdb_test "python print vdict\[two\]" "two str" "Test dictionary hash"
+    gdb_test "python print vdict\[three\]" "three str" "Test dictionary hash"
+    gdb_test "python print one.__hash__() == hash(one)" "True" "Test inbuilt hash"
+    gdb_test "python print one.__hash__() == id(one)" "True" "Test inbuilt id"
+}
+
+
 # Start with a fresh gdb.
 
 gdb_exit
@@ -409,6 +426,7 @@ test_value_boolean
 test_value_compare
 test_objfiles
 test_parse_and_eval
+test_value_hash
 
 # The following tests require execution.