[PATCH 3/5] gdb/python: implement DisassemblerResult.__str__ method

[Andrew Burgess <aburgess@redhat.com>]

Add the DisassemblerResult.__str__ method.  This gives the same result
as the DisassemblerResult.string attribute, but can be useful sometime
where a user just wants to print the DisassemblerResult object and
have GDB do something sane.

There's a test for the new functionality.
---
 gdb/python/py-disasm.c                 | 26 +++++++++++++++++---------
 gdb/testsuite/gdb.python/py-disasm.exp |  1 +
 gdb/testsuite/gdb.python/py-disasm.py  | 12 ++++++++++++
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/gdb/python/py-disasm.c b/gdb/python/py-disasm.c
index 999d0e0192c..c61fe70c26b 100644
--- a/gdb/python/py-disasm.c
+++ b/gdb/python/py-disasm.c
@@ -605,6 +605,21 @@ gdbpy_disassembler::read_memory_func (bfd_vma memaddr, gdb_byte *buff,
   return 0;
 }
 
+/* Implement __str__ for the DisassemblerResult type.  */
+
+static PyObject *
+disasmpy_result_str (PyObject *self)
+{
+  disasm_result_object *obj = (disasm_result_object *) self;
+
+  gdb_assert (obj->content != nullptr);
+  gdb_assert (obj->content->size () > 0);
+  gdb_assert (obj->length > 0);
+  return PyUnicode_Decode (obj->content->c_str (),
+			   obj->content->size (),
+			   host_charset (), nullptr);
+}
+
 /* Implement DisassemblerResult.length attribute, return the length of the
    disassembled instruction.  */
 
@@ -621,14 +636,7 @@ disasmpy_result_length (PyObject *self, void *closure)
 static PyObject *
 disasmpy_result_string (PyObject *self, void *closure)
 {
-  disasm_result_object *obj = (disasm_result_object *) self;
-
-  gdb_assert (obj->content != nullptr);
-  gdb_assert (obj->content->size () > 0);
-  gdb_assert (obj->length > 0);
-  return PyUnicode_Decode (obj->content->c_str (),
-			   obj->content->size (),
-			   host_charset (), nullptr);
+  return disasmpy_result_str (self);
 }
 
 /* Implement DisassemblerResult.__init__.  Takes two arguments, an
@@ -1140,7 +1148,7 @@ PyTypeObject disasm_result_object_type = {
   0,						/*tp_as_mapping*/
   0,						/*tp_hash */
   0,						/*tp_call*/
-  0,						/*tp_str*/
+  disasmpy_result_str,				/*tp_str*/
   0,						/*tp_getattro*/
   0,						/*tp_setattro*/
   0,						/*tp_as_buffer*/
diff --git a/gdb/testsuite/gdb.python/py-disasm.exp b/gdb/testsuite/gdb.python/py-disasm.exp
index 44b8398bf21..66ed39f048b 100644
--- a/gdb/testsuite/gdb.python/py-disasm.exp
+++ b/gdb/testsuite/gdb.python/py-disasm.exp
@@ -76,6 +76,7 @@ set test_plans \
 	 [list "ShowInfoRepr" "${base_pattern}\\s+## <gdb.disassembler.DisassembleInfo address=$hex>\r\n.*"] \
 	 [list "ShowInfoSubClassRepr" "${base_pattern}\\s+## <MyInfo address=$hex>\r\n.*"] \
 	 [list "ShowResultRepr" "${base_pattern}\\s+## <gdb.disassembler.DisassemblerResult length=$decimal string=\"\[^\r\n\]+\">\r\n.*"] \
+	 [list "ShowResultStr" "${base_pattern}\\s+## ${nop}\r\n.*"] \
 	 [list "GlobalPreInfoDisassembler" "${base_pattern}\\s+## ad = $hex, ar = ${curr_arch}\r\n.*"] \
 	 [list "GlobalPostInfoDisassembler" "${base_pattern}\\s+## ad = $hex, ar = ${curr_arch}\r\n.*"] \
 	 [list "GlobalReadDisassembler" "${base_pattern}\\s+## bytes =( $hex)+\r\n.*"] \
diff --git a/gdb/testsuite/gdb.python/py-disasm.py b/gdb/testsuite/gdb.python/py-disasm.py
index 977cdbf3c37..435a3bf5339 100644
--- a/gdb/testsuite/gdb.python/py-disasm.py
+++ b/gdb/testsuite/gdb.python/py-disasm.py
@@ -113,6 +113,18 @@ class ShowResultRepr(TestDisassembler):
         return DisassemblerResult(length=length, string=string)
 
 
+class ShowResultStr(TestDisassembler):
+    """Call the __str__ method on a DisassemblerResult object, incude the
+    resulting string in a comment within the disassembler output."""
+
+    def disassemble(self, info):
+        result = gdb.disassembler.builtin_disassemble(info)
+        comment = "\t## " + str(result)
+        string = result.string + comment
+        length = result.length
+        return DisassemblerResult(length=length, string=string)
+
+
 class GlobalPreInfoDisassembler(TestDisassembler):
     """Check the attributes of DisassembleInfo before disassembly has occurred."""
 
-- 
2.25.4