Extend synthetic children to produce synthetic values (as in, those that GetValueAsUnsigned(), GetValueAsCString() would return)

The way to do this is to write a synthetic child provider for your type, and have it vend the (optional) get_value function.
If get_value is defined, and it returns a valid SBValue, that SBValue's value (as in lldb_private::Value) will be used as the synthetic ValueObject's Value

The rationale for doing things this way is twofold:

- there are many possible ways to define a "value" (SBData, a Python number, ...) but SBValue seems general enough as a thing that stores a "value", so we just trade values that way and that keeps our currency trivial
- we could introduce a new level of layering (ValueObjectSyntheticValue), a new kind of formatter (synthetic value producer), but that would complicate the model (can I have a dynamic with no synthetic children but synthetic value? synthetic value with synthetic children but no dynamic?), and I really couldn't see much benefit to be reaped from this added complexity in the matrix
On the other hand, just defining a synthetic child provider with a get_value but returning no actual children is easy enough that it's not a significant road-block to adoption of this feature

Comes with a test case

llvm-svn: 219330

1 files changed, 28 insertions, 0 deletions

diff --git a/lldb/scripts/Python/python-wrapper.swig b/lldb/scripts/Python/python-wrapper.swig
index bf22198f4e4..9f9ebaded9d 100644
--- a/lldb/scripts/Python/python-wrapper.swig
+++ b/lldb/scripts/Python/python-wrapper.swig
@@ -723,6 +723,34 @@ LLDBSwigPython_MightHaveChildrenSynthProviderInstance
     return ret_val;
 }
 
+SWIGEXPORT PyObject*
+LLDBSwigPython_GetValueSynthProviderInstance
+(
+    PyObject *implementor
+)
+{
+    PyObject* ret_val = nullptr;
+
+    static char callee_name[] = "get_value";
+
+    PyObject* py_return = LLDBSwigPython_CallOptionalMember(implementor,callee_name, Py_None);
+
+    if (py_return == Py_None || py_return == nullptr)
+        ret_val = nullptr;
+
+    lldb::SBValue* sbvalue_ptr = NULL;
+    
+    if (SWIG_ConvertPtr(py_return, (void**)&sbvalue_ptr, SWIGTYPE_p_lldb__SBValue, 0) == -1)
+        ret_val = nullptr;
+    else if (sbvalue_ptr == NULL)
+        ret_val = nullptr;
+    else
+        ret_val = py_return;
+
+    Py_XDECREF(py_return);
+    return ret_val;
+}
+
 SWIGEXPORT void*
 LLDBSWIGPython_CastPyObjectToSBValue
 (