Fix accessing a method's fields from Python

Considering this example:

struct C
{
  int func() { return 1; }
} c;
int main()
{
  return c.func();
}

Accessing the fields of C::func, when requesting the function by its
type, works:

(gdb) py print(gdb.parse_and_eval('C::func').type.fields()[0].type)
C * const

But when trying to do the same via a class instance, it fails:

(gdb) py print(gdb.parse_and_eval('c')['func'].type.fields()[0].type)
Traceback (most recent call last):
  File "<string>", line 1, in <module>
TypeError: Type is not a structure, union, enum, or function type.
Error while executing Python code.

The difference is that in the former the function type is TYPE_CODE_FUNC:

(gdb) py print(gdb.parse_and_eval('C::func').type.code == gdb.TYPE_CODE_FUNC)
True

And in the latter the function type is TYPE_CODE_METHOD:

(gdb) py print(gdb.parse_and_eval('c')['func'].type.code == gdb.TYPE_CODE_METHOD)
True

So this adds the functionality for TYPE_CODE_METHOD as well.

gdb/ChangeLog:

2020-12-18  Hannes Domani  <ssbssa@yahoo.de>

	* python/py-type.c (typy_get_composite): Add TYPE_CODE_METHOD.

gdb/testsuite/ChangeLog:

2020-12-18  Hannes Domani  <ssbssa@yahoo.de>

	* gdb.python/py-type.exp: Add tests for TYPE_CODE_METHOD.

4 files changed, 12 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9b7b010..1a104b1 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2020-12-18  Hannes Domani  <ssbssa@yahoo.de>
+
+	* python/py-type.c (typy_get_composite): Add TYPE_CODE_METHOD.
+
 2020-12-18  Jameson Nash  <vtjnash@gmail.com>
 
 	* coffread.c (linetab_offset): Change type to file_ptr.
diff --git a/gdb/python/py-type.c b/gdb/python/py-type.c
index 1c7cacb..3fc0f61 100644
--- a/gdb/python/py-type.c
+++ b/gdb/python/py-type.c
@@ -471,6 +471,7 @@ typy_get_composite (struct type *type)
   if (type->code () != TYPE_CODE_STRUCT
       && type->code () != TYPE_CODE_UNION
       && type->code () != TYPE_CODE_ENUM
+      && type->code () != TYPE_CODE_METHOD
       && type->code () != TYPE_CODE_FUNC)
     {
       PyErr_SetString (PyExc_TypeError,
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 24df951..7342563 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2020-12-18  Hannes Domani  <ssbssa@yahoo.de>
+
+	* gdb.python/py-type.exp: Add tests for TYPE_CODE_METHOD.
+
 2020-12-18  Tom Tromey  <tromey@adacore.com>
 
 	* gdb.ada/fixed_points.exp: Also run with
diff --git a/gdb/testsuite/gdb.python/py-type.exp b/gdb/testsuite/gdb.python/py-type.exp
index c01442c..5166f9e 100644
--- a/gdb/testsuite/gdb.python/py-type.exp
+++ b/gdb/testsuite/gdb.python/py-type.exp
@@ -83,15 +83,18 @@ proc test_fields {lang} {
       gdb_test "python print (gdb.parse_and_eval ('C::a_method').type.fields ()\[0\].type)" "C \\* const"
       gdb_test "python print (gdb.parse_and_eval ('C::a_method').type.fields ()\[1\].type)" "int"
       gdb_test "python print (gdb.parse_and_eval ('C::a_method').type.fields ()\[2\].type)" "char"
+      gdb_test "python print (gdb.parse_and_eval ('c')\['a_method'\].type.fields ()\[0\].type)" "C \\* const"
 
       gdb_test "python print (len (gdb.parse_and_eval ('C::a_const_method').type.fields ()))" "3"
       gdb_test "python print (gdb.parse_and_eval ('C::a_const_method').type.fields ()\[0\].type)" "const C \\* const"
       gdb_test "python print (gdb.parse_and_eval ('C::a_const_method').type.fields ()\[1\].type)" "int"
       gdb_test "python print (gdb.parse_and_eval ('C::a_const_method').type.fields ()\[2\].type)" "char"
+      gdb_test "python print (gdb.parse_and_eval ('c')\['a_const_method'\].type.fields ()\[0\].type)" "const C \\* const"
 
       gdb_test "python print (len (gdb.parse_and_eval ('C::a_static_method').type.fields ()))" "2"
       gdb_test "python print (gdb.parse_and_eval ('C::a_static_method').type.fields ()\[0\].type)" "int"
       gdb_test "python print (gdb.parse_and_eval ('C::a_static_method').type.fields ()\[1\].type)" "char"
+      gdb_test "python print (gdb.parse_and_eval ('c')\['a_static_method'\].type.fields ()\[0\].type)" "int"
     }
 
     # Test normal fields usage in structs.