From: Ondřej Bílka <neleai@seznam.cz>
Date: Wed, 26 Feb 2014 12:13:09 +0000 (+0100)
Subject: Simplify calloc implementation.
X-Git-Tag: glibc-2.20~830
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4248f0da6ff9e7dd63464cdecec2dec332dfc2f0;p=platform%2Fupstream%2Fglibc.git

Simplify calloc implementation.

To make future improvements of allocator simpler we could for now calloc
just call malloc and memset. With that we could omit a changes that
would duplicate malloc changes anyway.
---

diff --git a/ChangeLog b/ChangeLog
index e6246ea..beb3598 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2014-02-26  Ondřej Bílka  <neleai@seznam.cz>
+
+	* malloc/malloc.c (__libc_calloc): Simplify implementation.
+
 2014-02-25  Carlos O'Donell  <carlos@redhat.com>
 
 	[BZ #16632]
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 9a45707..74ad92d 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3141,13 +3141,8 @@ __libc_pvalloc (size_t bytes)
 void *
 __libc_calloc (size_t n, size_t elem_size)
 {
-  mstate av;
-  mchunkptr oldtop, p;
-  INTERNAL_SIZE_T bytes, sz, csz, oldtopsize;
+  INTERNAL_SIZE_T bytes;
   void *mem;
-  unsigned long clearsize;
-  unsigned long nclears;
-  INTERNAL_SIZE_T *d;
 
   /* size_t is unsigned so the behavior on overflow is defined.  */
   bytes = n * elem_size;
@@ -3166,113 +3161,15 @@ __libc_calloc (size_t n, size_t elem_size)
     atomic_forced_read (__malloc_hook);
   if (__builtin_expect (hook != NULL, 0))
     {
-      sz = bytes;
-      mem = (*hook)(sz, RETURN_ADDRESS (0));
-      if (mem == 0)
-        return 0;
-
-      return memset (mem, 0, sz);
-    }
-
-  sz = bytes;
-
-  arena_get (av, sz);
-  if (!av)
-    return 0;
-
-  /* Check if we hand out the top chunk, in which case there may be no
-     need to clear. */
-#if MORECORE_CLEARS
-  oldtop = top (av);
-  oldtopsize = chunksize (top (av));
-# if MORECORE_CLEARS < 2
-  /* Only newly allocated memory is guaranteed to be cleared.  */
-  if (av == &main_arena &&
-      oldtopsize < mp_.sbrk_base + av->max_system_mem - (char *) oldtop)
-    oldtopsize = (mp_.sbrk_base + av->max_system_mem - (char *) oldtop);
-# endif
-  if (av != &main_arena)
-    {
-      heap_info *heap = heap_for_ptr (oldtop);
-      if (oldtopsize < (char *) heap + heap->mprotect_size - (char *) oldtop)
-        oldtopsize = (char *) heap + heap->mprotect_size - (char *) oldtop;
-    }
-#endif
-  mem = _int_malloc (av, sz);
-
-
-  assert (!mem || chunk_is_mmapped (mem2chunk (mem)) ||
-          av == arena_for_chunk (mem2chunk (mem)));
-
-  if (mem == 0)
-    {
-      LIBC_PROBE (memory_calloc_retry, 1, sz);
-      av = arena_get_retry (av, sz);
-      if (__builtin_expect (av != NULL, 1))
-        {
-          mem = _int_malloc (av, sz);
-          (void) mutex_unlock (&av->mutex);
-        }
-      if (mem == 0)
-        return 0;
+      mem = (*hook)(bytes, RETURN_ADDRESS (0));
     }
   else
-    (void) mutex_unlock (&av->mutex);
-  p = mem2chunk (mem);
-
-  /* Two optional cases in which clearing not necessary */
-  if (chunk_is_mmapped (p))
-    {
-      if (__builtin_expect (perturb_byte, 0))
-        return memset (mem, 0, sz);
-
-      return mem;
-    }
+    mem = __libc_malloc (bytes);
 
-  csz = chunksize (p);
-
-#if MORECORE_CLEARS
-  if (perturb_byte == 0 && (p == oldtop && csz > oldtopsize))
-    {
-      /* clear only the bytes from non-freshly-sbrked memory */
-      csz = oldtopsize;
-    }
-#endif
-
-  /* Unroll clear of <= 36 bytes (72 if 8byte sizes).  We know that
-     contents have an odd number of INTERNAL_SIZE_T-sized words;
-     minimally 3.  */
-  d = (INTERNAL_SIZE_T *) mem;
-  clearsize = csz - SIZE_SZ;
-  nclears = clearsize / sizeof (INTERNAL_SIZE_T);
-  assert (nclears >= 3);
-
-  if (nclears > 9)
-    return memset (d, 0, clearsize);
-
-  else
-    {
-      *(d + 0) = 0;
-      *(d + 1) = 0;
-      *(d + 2) = 0;
-      if (nclears > 4)
-        {
-          *(d + 3) = 0;
-          *(d + 4) = 0;
-          if (nclears > 6)
-            {
-              *(d + 5) = 0;
-              *(d + 6) = 0;
-              if (nclears > 8)
-                {
-                  *(d + 7) = 0;
-                  *(d + 8) = 0;
-                }
-            }
-        }
-    }
+  if (mem == 0)
+    return 0;
 
-  return mem;
+  return memset (mem, 0, bytes);
 }
 
 /*