[LLDB] bugfix: command script add -f doesn't work for some callables

Summary:
When users define a debugger command from python, they provide a callable
object.   Because the signature of the function has been extended, LLDB
needs to inspect the number of parameters the callable can take.

The rule it was using to decide was weird, apparently not tested, and
giving wrong results for some kinds of python callables.

This patch replaces the weird rule with a simple one: if the callable can
take 5 arguments, it gets the 5 argument version of the signature.
Otherwise it gets the old 4 argument version.

It also adds tests with a bunch of different kinds of python callables
with both 4 and 5 arguments.

Reviewers: JDevlieghere, clayborg, labath, jingham

Reviewed By: labath

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D69014

llvm-svn: 375333

1 files changed, 5 insertions, 2 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
index 5823f740a53..0cdb63f17c9 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
@@ -604,6 +604,11 @@ public:
   using TypedPythonObject::TypedPythonObject;
 
   struct ArgInfo {
+    /* the largest number of positional arguments this callable
+     * can accept, or UNBOUNDED, ie UINT_MAX if it's a varargs
+     * function and can accept an arbitrary number */
+    unsigned max_positional_args;
+    static constexpr unsigned UNBOUNDED = UINT_MAX; // FIXME c++17 inline
     /* the number of positional arguments, including optional ones,
      * and excluding varargs.  If this is a bound method, then the
      * count will still include a +1 for self.
@@ -614,8 +619,6 @@ public:
     int count;
     /* does the callable have positional varargs? */
     bool has_varargs : 1; // FIXME delete this
-    /* is the callable a bound method written in python? */
-    bool is_bound_method : 1; // FIXME delete this
   };
 
   static bool Check(PyObject *py_obj);