Allocator: simplify using guarded allocator in C++ code

Using the `MEM_*` API from C++ code was a bit annoying:
* When converting C to C++ code, one often has to add a type cast on
  returned `void *`. That leads to having the same type name three times
  in the same line. This patch reduces the amount to two and removes the
  `sizeof(...)` from the line.
* The existing alternative of using `OBJECT_GUARDED_NEW` looks a out
  of place compared to other allocation methods. Sometimes
  `MEM_CXX_CLASS_ALLOC_FUNCS` can be used when structs are defined
  in C++ code. It doesn't look great but it's definitely better. The downside
  is that it makes the name of the allocation less useful. That's because
  the same name is used for all allocations of a type, independend of
  where it is allocated.

This patch introduces three new functions: `MEM_new`, `MEM_cnew` and
`MEM_delete`. These cover the majority of use cases (array allocation is
not covered).

The `OBJECT_GUARDED_*` macros are removed because they are not
needed anymore.

Differential Revision: https://developer.blender.org/D13502

1 files changed, 15 insertions, 3 deletions

diff --git a/intern/libmv/intern/utildefines.h b/intern/libmv/intern/utildefines.h
index 052052a1d76..8b37253698d 100644
--- a/intern/libmv/intern/utildefines.h
+++ b/intern/libmv/intern/utildefines.h
@@ -27,9 +27,21 @@
 
 #ifdef WITH_LIBMV_GUARDED_ALLOC
 #  include "MEM_guardedalloc.h"
-#  define LIBMV_OBJECT_NEW OBJECT_GUARDED_NEW
-#  define LIBMV_OBJECT_DELETE OBJECT_GUARDED_DELETE
-#  define LIBMV_OBJECT_DELETE OBJECT_GUARDED_DELETE
+#  if defined __GNUC__
+#    define LIBMV_OBJECT_NEW(type, args...)                                    \
+      new (MEM_mallocN(sizeof(type), __func__)) type(args)
+#  else
+#    define LIBMV_OBJECT_NEW(type, ...)                                        \
+      new (MEM_mallocN(sizeof(type), __FUNCTION__)) type(__VA_ARGS__)
+#  endif
+#  define LIBMV_OBJECT_DELETE(what, type)                                      \
+    {                                                                          \
+      if (what) {                                                              \
+        ((type*)what)->~type();                                                \
+        MEM_freeN(what);                                                       \
+      }                                                                        \
+    }                                                                          \
+    (void)0
 #  define LIBMV_STRUCT_NEW(type, count)                                        \
     (type*)MEM_mallocN(sizeof(type) * count, __func__)
 #  define LIBMV_STRUCT_DELETE(what) MEM_freeN(what)