Remove duplication of random numbers generator formula

(refactoring)

* dbg_mlc.c [LINT2] (GC_random): Rename to GC_rand and change return
type from long to int; define as static (to match that in disclaim_test
but w/o GC_ATTR_NO_SANITIZE_THREAD); define only if KEEP_BACK_PTRS.
* dbg_mlc.c [LINT2] (GC_random): Change type of seed local variable to
GC_RAND_STATE_T; use GC_RAND_NEXT() instead of the direct RNG formula.
* tests/disclaim_test.c [GC_PTHREADS || LINT2] (GC_rand): Likewise.
* tests/disclaim_weakmap_test.c [GC_PTHREADS || LINT2] (GC_rand):
Likewise.
* dbg_mlc.c [KEEP_BACK_PTRS && LINT2] (RANDOM): Replace GC_random() to
(int)GC_rand().
* dbg_mlc.c [KEEP_BACK_PTRS && !LINT2] (GC_RAND_MAX): Undefine before
redefine.
* dbg_mlc.c [KEEP_BACK_PTRS] (GC_generate_random_heap_address): Cast
RANDOM() and GC_RAND_MAX to word.
* include/private/gc_priv.h [LINT2] (GC_random): Do not declare.
* include/private/gc_priv.h [THREADS || LINT2] (GC_RAND_STATE_T,
GC_RAND_NEXT): New macro; add comment.
* include/private/gc_priv.h [THREADS || LINT2] (GC_RAND_MAX): Cast to
int; define also in case of THREADS.
* tests/disclaim_bench.c [LINT2] (seed): New static variable.
* tests/disclaim_bench.c [LINT2] (rand): Define to GC_RAND_NEXT(&seed)
instead of (int)GC_random().
* tests/disclaim_test.c [GC_PTHREADS || LINT2] (GC_rand): Do not refer
GC_random in comment.

1 files changed, 12 insertions, 14 deletions

diff --git a/dbg_mlc.c b/dbg_mlc.c
index b333a128..1ffee0f4 100644
--- a/dbg_mlc.c
+++ b/dbg_mlc.c
@@ -54,23 +54,20 @@
   }
 #endif /* !SHORT_DBG_HDRS */
 
+#ifdef KEEP_BACK_PTRS
+
 #ifdef LINT2
-  long GC_random(void)
+  static int GC_rand(void)
   {
-    static unsigned seed = 1; /* not thread-safe */
+    static GC_RAND_STATE_T seed;
 
-    /* Linear congruential pseudo-random numbers generator.     */
-    seed = (seed * 1103515245U + 12345) & GC_RAND_MAX; /* overflow is ok */
-    return (long)seed;
+    return GC_RAND_NEXT(&seed);
   }
-#endif
 
-#ifdef KEEP_BACK_PTRS
-
-#ifdef LINT2
-# define RANDOM() GC_random()
+# define RANDOM() (long)GC_rand()
 #else
 # include <stdlib.h>
+# undef GC_RAND_MAX
 # define GC_RAND_MAX RAND_MAX
 
 # if defined(__GLIBC__) || defined(SOLARIS) \
@@ -163,16 +160,17 @@
   GC_API void * GC_CALL GC_generate_random_heap_address(void)
   {
     size_t i;
-    word heap_offset = RANDOM();
+    word heap_offset = (word)RANDOM();
 
-    if (GC_heapsize > GC_RAND_MAX) {
+    if (GC_heapsize > (word)GC_RAND_MAX) {
         heap_offset *= GC_RAND_MAX;
-        heap_offset += RANDOM();
+        heap_offset += (word)RANDOM();
     }
     heap_offset %= GC_heapsize;
         /* This doesn't yield a uniform distribution, especially if     */
-        /* e.g. RAND_MAX = 1.5* GC_heapsize.  But for typical cases,    */
+        /* e.g. RAND_MAX is 1.5*GC_heapsize.  But for typical cases,    */
         /* it's not too bad.                                            */
+
     for (i = 0;; ++i) {
         size_t size;