gccutils: get pretty-printing working again

* Add new function ``gcc.is_cplusplus`` to determine if we are
  compiling C++

* Use ``gcc.is_cplusplus`` in gccutils to not iterate over fullname
  when we are not using C++ (resolves davidmalcolm#72)

* Allow accessing ``gcc.Type.sizeof`` to raise a TypeError while
  pretty-printing to be silently ignored and not added to attributes

* Use ``pp_newline_and_flush`` instead of ``pp_newline`` in
  ``PyGccPrettyPrinter_as_string`` when we are using GCC 5.3 or
  later (as this provides the historic functionality relied upon)

Author: jackrosenthal

docs/versions.rst

@@ -83,3 +83,8 @@ On my machine, running this currently gives::
    4.8           4008
    4.9           4009
    ===========   ========================
+
+.. py:function:: gcc.is_cplusplus()
+   :rtype: bool
+
+   Determine whether or not we are compiling C++

gcc-python-pretty-printer.c

@@ -88,7 +88,15 @@ PyGccPrettyPrinter_as_string(PyObject *obj)
     ppobj = (struct PyGccPrettyPrinter *)obj;
 
     /* Flush the pp first.  This forcibly adds a trailing newline: */
+#if (GCC_VERSION < 5003)
     pp_flush(&ppobj->pp);
+#else
+    /*
+     * pp_newline_and_flush provides the same functionality on GCC 5.3
+     * and later
+     */
+    pp_newline_and_flush(&ppobj->pp);
+#endif
 
     /* Convert to a python string, leaving off the trailing newline: */
     len = strlen(ppobj->buf);

gcc-python-tree.c

@@ -47,19 +47,6 @@ extern PyGccWrapperTypeObject PyGccIntegerCst_TypeObj;
 
 __typeof__ (lang_check_failed) lang_check_failed __attribute__ ((weak));
 
-
-/*
-  Unfortunately, decl_as_string() is only available from the C++
-  frontend: cc1plus (it's defined in gcc/cp/error.c).
-
-  See http://gcc.gnu.org/ml/gcc/2011-11/msg00504.html
-
-  Hence we redeclare the symbol as weak, and then check its definition
-  against 0 before using it.
-*/
-
-__typeof__ (decl_as_string) decl_as_string __attribute__ ((weak));
-
 /* Similar for namespace_binding, though gcc 8's r247654 (aka
    f906dcc33dd818b71e16c88cef38f33c161070db) replaced it with
    get_namespace_value and reversed the order of the params

gcc-python.c

@@ -401,6 +401,12 @@ PyGcc_get_is_lto(PyObject *self, PyObject *noargs)
     return PyBool_FromLong(in_lto_p);
 }
 
+static PyObject *
+PyGcc_get_is_cplusplus(PyObject *self, PyObject *noargs)
+{
+    return PyBool_FromLong(decl_as_string != NULL);
+}
+
 static PyMethodDef GccMethods[] = {
     {"register_attribute",
      (PyCFunction)PyGcc_RegisterAttribute,
@@ -491,6 +497,9 @@ static PyMethodDef GccMethods[] = {
     {"is_lto", PyGcc_get_is_lto, METH_NOARGS,
      "Determine whether or not we're being invoked during link-time optimization"},
 
+    {"is_cplusplus", PyGcc_get_is_cplusplus, METH_NOARGS,
+     "Determine whether or not we're compiling C++"},
+
     /* Garbage collection */
     {"_force_garbage_collection", PyGcc__force_garbage_collection, METH_NOARGS,
      "Forcibly trigger a single run of GCC's garbage collector"},

gcc-python.h

@@ -39,6 +39,7 @@
 #include "params.h"
 #endif
 #include "gcc-c-api/gcc-cfg.h"
+#include "cp/cp-tree.h" /* for decl_as_string */
 
 /* GCC doesn't seem to give us an ID for "invalid event", so invent one: */
 #define GCC_PYTHON_PLUGIN_BAD_EVENT (0xffff)
@@ -69,6 +70,18 @@
   #define CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF(typename)
 #endif
 
+/*
+  Unfortunately, decl_as_string() is only available from the C++
+  frontend: cc1plus (it's defined in gcc/cp/error.c).
+
+  See http://gcc.gnu.org/ml/gcc/2011-11/msg00504.html
+
+  Hence we redeclare the symbol as weak, and then check its definition
+  against 0 before using it.
+*/
+
+__typeof__ (decl_as_string) decl_as_string __attribute__ ((weak));
+
 /*
   PyObject shared header for wrapping GCC objects, for integration
   with GCC's garbage collector (so that things we wrap don't get collected

gccutils/__init__.py

@@ -148,7 +148,18 @@ def iter_tree_attrs(self, obj):
             # Ignore private and "magic" attributes:
             if name.startswith('_'):
                 continue
-            value = getattr(obj, name)
+            if (isinstance(obj, gcc.FunctionDecl)
+                    and name == 'fullname'
+                    and not gcc.is_cplusplus()):
+                continue
+            try:
+                value = getattr(obj, name)
+            except TypeError as e:
+                # for gcc.Type, sizeof is not always defined, and
+                # TypeError is raise under this condition
+                if not isinstance(obj, gcc.Type) or name != 'sizeof':
+                    raise e
+                continue
             # Ignore methods:
             if hasattr(value, '__call__'):
                 continue