[binutils-gdb] Allow calling of C++ methods from python

[binutils-gdb] Allow calling of C++ methods from python

[Hannes Domani]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=2e08907d0672711617f71ef4604df190106b992e

commit 2e08907d0672711617f71ef4604df190106b992e
Author: Hannes Domani <ssbssa@yahoo.de>
Date:   Thu Feb 8 20:09:25 2024 +0100

    Allow calling of C++ methods from python
    
    Currently it's not possible to call C++ methods from python.
    Using this example:
    ```
    class B
    {
      static int static_func ();
      int arg0_func ();
      int arg1_func (int arg1);
      int arg2_func (int arg1, int arg2);
    };
    
    B *b_obj = new B;
    ```
    
    Trying to call B::static_func gives this error:
    ```
    (gdb) py b_obj = gdb.parse_and_eval('b_obj')
    (gdb) py print(b_obj['static_func']())
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    RuntimeError: Value is not callable (not TYPE_CODE_FUNC).
    Error while executing Python code.
    ```
    
    TYPE_CODE_METHOD was simply missing as a possible type in
    valpy_call, now the same is possible:
    ```
    (gdb) py b_obj = gdb.parse_and_eval('b_obj')
    (gdb) py print(b_obj['static_func']())
    1111
    ```
    
    Note that it's necessary to explicitely add the this pointer
    as the first argument in a call of non-static methods:
    ```
    (gdb) py print(b_obj['arg0_func']())
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    gdb.error: Too few arguments in function call.
    Error while executing Python code.
    (gdb) py print(b_obj['arg0_func'](b_obj))
    198
    ```
    
    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=13326
    Approved-By: Tom Tromey <tom@tromey.com>

Diff:
---
 gdb/python/py-value.c                    |  5 +++--
 gdb/testsuite/gdb.python/py-value-cc.cc  | 25 +++++++++++++++++++++++++
 gdb/testsuite/gdb.python/py-value-cc.exp | 12 ++++++++++++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/gdb/python/py-value.c b/gdb/python/py-value.c
index 151b8801b88..89ca0982e59 100644
--- a/gdb/python/py-value.c
+++ b/gdb/python/py-value.c
@@ -1214,10 +1214,11 @@ valpy_call (PyObject *self, PyObject *args, PyObject *keywords)
       GDB_PY_HANDLE_EXCEPTION (except);
     }
 
-  if (ftype->code () != TYPE_CODE_FUNC)
+  if (ftype->code () != TYPE_CODE_FUNC && ftype->code () != TYPE_CODE_METHOD)
     {
       PyErr_SetString (PyExc_RuntimeError,
-		       _("Value is not callable (not TYPE_CODE_FUNC)."));
+		       _("Value is not callable (not TYPE_CODE_FUNC"
+			 " or TYPE_CODE_METHOD)."));
       return NULL;
     }
 
diff --git a/gdb/testsuite/gdb.python/py-value-cc.cc b/gdb/testsuite/gdb.python/py-value-cc.cc
index c0e68c1174a..2d38a26d948 100644
--- a/gdb/testsuite/gdb.python/py-value-cc.cc
+++ b/gdb/testsuite/gdb.python/py-value-cc.cc
@@ -37,8 +37,33 @@ union U {
 class B : public A {
  public:
   char a;
+
+  static int static_func ();
+  int arg0_func ();
+  int arg1_func (int arg1);
+  int arg2_func (int arg1, int arg2);
 };
 
+int B::static_func ()
+{
+  return 1111;
+}
+
+int B::arg0_func ()
+{
+  return A::a + a;
+}
+
+int B::arg1_func (int arg1)
+{
+  return a * arg1;
+}
+
+int B::arg2_func (int arg1, int arg2)
+{
+  return a * arg1 + arg2;
+}
+
 struct X
 {
   union { int x; char y; };
diff --git a/gdb/testsuite/gdb.python/py-value-cc.exp b/gdb/testsuite/gdb.python/py-value-cc.exp
index f58acd21ccf..17a67e20c1c 100644
--- a/gdb/testsuite/gdb.python/py-value-cc.exp
+++ b/gdb/testsuite/gdb.python/py-value-cc.exp
@@ -99,3 +99,15 @@ gdb_test "python print(uu\[uu_fields\[1\]\]\['a'\])" "1000" "uu.a via field"
 # Test overloaded operators.
 gdb_test_no_output "python a = gdb.parse_and_eval('a')" "init a"
 gdb_test "python print(a + 5)" "10" "a + 5"
+
+# Test inferior function calls of methods.
+gdb_test "py print(b_obj\['static_func'\]())" "1111"
+gdb_test "py print(b_obj\['arg0_func'\]())" ".*Too few arguments in function call.*"
+gdb_test "py print(b_obj\['arg0_func'\](b_obj))" "198"
+gdb_test "py print(b_obj\['arg1_func'\]())" ".*Too few arguments in function call.*"
+gdb_test "py print(b_obj\['arg1_func'\](b_obj))" ".*Too few arguments in function call.*"
+gdb_test "py print(b_obj\['arg1_func'\](b_obj, 3))" "294"
+gdb_test "py print(b_obj\['arg2_func'\]())" ".*Too few arguments in function call.*"
+gdb_test "py print(b_obj\['arg2_func'\](b_obj))" ".*Too few arguments in function call.*"
+gdb_test "py print(b_obj\['arg2_func'\](b_obj, 4))" ".*Too few arguments in function call.*"
+gdb_test "py print(b_obj\['arg2_func'\](b_obj, 5, 6))" "496"