PR#6084: Define caml_modify and caml_initialize as weak symbols to help

with Netmulticore.  (Reflecting commit r13957 on version/4.01)


git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13958 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

Changes

@@ -178,6 +178,8 @@ Bug fixes:
 - PR#6056: Using 'match' prevents generalization of values
 - PR#6060: ocamlbuild rules for -principal, -strict-sequence and -short-paths
 - PR#6090: Module constraint + private type seems brocken in ocaml 4.01.0
+- PR#6084: Define caml_modify and caml_initialize as weak symbols to help
+  with Netmulticore
 - PR#6109: Typos in ocamlbuild error messages
 
 Internals:

byterun/memory.c

@@ -502,7 +502,8 @@ CAMLexport void caml_adjust_gc_speed (mlsize_t res, mlsize_t max)
 */
 /* [caml_initialize] never calls the GC, so you may call it while a block is
    unfinished (i.e. just after a call to [caml_alloc_shr].) */
-CAMLexport void caml_initialize (value *fp, value val)
+/* PR#6084 workaround: define it as a weak symbol */
+CAMLexport CAMLweakdef void caml_initialize (value *fp, value val)
 {
   CAMLassert(Is_in_heap(fp));
   *fp = val;
@@ -522,10 +523,10 @@ CAMLexport void caml_initialize (value *fp, value val)
    in the minor heap instead of in the major heap.  In this case, it
    is a bit slower than simple assignment.
    In particular, you can use [caml_modify] when you don't know whether the
-   block being changed is in the minor heap or the major heap.
-*/
+   block being changed is in the minor heap or the major heap. */
+/* PR#6084 workaround: define it as a weak symbol */
 
-CAMLexport void caml_modify (value *fp, value val)
+CAMLexport CAMLweakdef void caml_modify (value *fp, value val)
 {
   /* The write barrier implemented by [caml_modify] checks for the 
      following two conditions and takes appropriate action:

byterun/misc.h

@@ -51,6 +51,14 @@ typedef char * addr;
 #define CAMLprim
 #define CAMLextern extern
 
+/* Weak function definitions that can be overriden by external libs */
+/* Conservatively restricted to ELF and MacOSX platforms */
+#if defined(__GNUC__) && (defined (__ELF__) || defined(__APPLE__))
+#define CAMLweakdef __attribute__((weak))
+#else
+#define CAMLweakdef
+#endif
+
 /* Assertions */
 
 /* <private> */