Fix GC_add_roots_inner for Mac OS X (enable GC_dyld_image_add to

pass unaligned segment start to GC_add_roots)

* mark_rts.c (GC_add_roots_inner): Round "b" pointer up to word
boundary.
* include/gc.h (GC_add_roots): Update the comment.

1 files changed, 5 insertions, 4 deletions

diff --git a/mark_rts.c b/mark_rts.c
index b7b81320..58f31df2 100644
--- a/mark_rts.c
+++ b/mark_rts.c
@@ -156,11 +156,12 @@ void GC_add_roots_inner(ptr_t b, ptr_t e, GC_bool tmp)
 {
     struct roots * old;
 
-    /* Adjust and check range boundaries for safety */
-    GC_ASSERT((word)b % sizeof(word) == 0);
-    e = (ptr_t)((word)e & ~(sizeof(word) - 1));
     GC_ASSERT(b <= e);
-    if (b == e) return;  /* nothing to do? */
+    b = (ptr_t)(((word)b + (sizeof(word) - 1)) & ~(sizeof(word) - 1));
+                                        /* round b up to word boundary */
+    e = (ptr_t)((word)e & ~(sizeof(word) - 1));
+                                        /* round e down to word boundary */
+    if (b >= e) return; /* nothing to do */
 
 #   if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32)
       /* Spend the time to ensure that there are no overlapping */