Use alignment macros, pagesize and powerof2.

We are replacing all of the bespoke alignment code with
ALIGN_UP, ALIGN_DOWN, PTR_ALIGN_UP, and PTR_ALIGN_DOWN.
This cleans up malloc/malloc.c, malloc/arena.c, and
elf/dl-reloc.c. It also makes all the code consistently
use pagesize, and powerof2 as required.

Code size is reduced with the removal of precomputed
pagemask, and use of pagesize instead. No measurable
difference in performance.

No regressions on x86_64.

1 files changed, 22 insertions, 20 deletions

diff --git a/malloc/malloc.c b/malloc/malloc.c
index aa7edbfd45..ad9487e5e6 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -241,6 +241,9 @@
 /* For MIN, MAX, powerof2.  */
 #include <sys/param.h>
 
+/* For ALIGN_UP.  */
+#include <libc-internal.h>
+
 
 /*
   Debugging:
@@ -2111,7 +2114,7 @@ do_check_malloc_state (mstate av)
     return;
 
   /* pagesize is a power of 2 */
-  assert ((GLRO (dl_pagesize) & (GLRO (dl_pagesize) - 1)) == 0);
+  assert (powerof2(GLRO (dl_pagesize)));
 
   /* A contiguous main_arena is consistent with sbrk_base.  */
   if (av == &main_arena && contiguous (av))
@@ -2266,7 +2269,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
   unsigned long remainder_size;   /* its size */
 
 
-  size_t pagemask = GLRO (dl_pagesize) - 1;
+  size_t pagesize = GLRO (dl_pagesize);
   bool tried_mmap = false;
 
 
@@ -2292,9 +2295,9 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
          need for further alignments unless we have have high alignment.
        */
       if (MALLOC_ALIGNMENT == 2 * SIZE_SZ)
-        size = (nb + SIZE_SZ + pagemask) & ~pagemask;
+        size = ALIGN_UP (nb + SIZE_SZ, pagesize);
       else
-        size = (nb + SIZE_SZ + MALLOC_ALIGN_MASK + pagemask) & ~pagemask;
+        size = ALIGN_UP (nb + SIZE_SZ + MALLOC_ALIGN_MASK, pagesize);
       tried_mmap = true;
 
       /* Don't try if size wraps around 0 */
@@ -2367,7 +2370,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
   assert ((old_top == initial_top (av) && old_size == 0) ||
           ((unsigned long) (old_size) >= MINSIZE &&
            prev_inuse (old_top) &&
-           ((unsigned long) old_end & pagemask) == 0));
+           ((unsigned long) old_end & (pagesize - 1)) == 0));
 
   /* Precondition: not enough current space to satisfy nb request */
   assert ((unsigned long) (old_size) < (unsigned long) (nb + MINSIZE));
@@ -2447,7 +2450,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
          previous calls. Otherwise, we correct to page-align below.
        */
 
-      size = (size + pagemask) & ~pagemask;
+      size = ALIGN_UP (size, pagesize);
 
       /*
          Don't try to call MORECORE if argument is so big as to appear
@@ -2481,7 +2484,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
 
           /* Cannot merge with old top, so add its size back in */
           if (contiguous (av))
-            size = (size + old_size + pagemask) & ~pagemask;
+            size = ALIGN_UP (size + old_size, pagesize);
 
           /* If we are relying on mmap as backup, then use larger units */
           if ((unsigned long) (size) < (unsigned long) (MMAP_AS_MORECORE_SIZE))
@@ -2587,7 +2590,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
 
                   /* Extend the end address to hit a page boundary */
                   end_misalign = (INTERNAL_SIZE_T) (brk + size + correction);
-                  correction += ((end_misalign + pagemask) & ~pagemask) - end_misalign;
+                  correction += (ALIGN_UP (end_misalign, pagesize)) - end_misalign;
 
                   assert (correction >= 0);
                   snd_brk = (char *) (MORECORE (correction));
@@ -2738,10 +2741,10 @@ systrim (size_t pad, mstate av)
   long released;         /* Amount actually released */
   char *current_brk;     /* address returned by pre-check sbrk call */
   char *new_brk;         /* address returned by post-check sbrk call */
-  size_t pagesz;
+  size_t pagesize;
   long top_area;
 
-  pagesz = GLRO (dl_pagesize);
+  pagesize = GLRO (dl_pagesize);
   top_size = chunksize (av->top);
 
   top_area = top_size - MINSIZE - 1;
@@ -2749,7 +2752,7 @@ systrim (size_t pad, mstate av)
     return 0;
 
   /* Release in pagesize units, keeping at least one page */
-  extra = (top_area - pad) & ~(pagesz - 1);
+  extra = (top_area - pad) & ~(pagesize - 1);
 
   if (extra == 0)
     return 0;
@@ -2834,7 +2837,7 @@ static mchunkptr
 internal_function
 mremap_chunk (mchunkptr p, size_t new_size)
 {
-  size_t page_mask = GLRO (dl_pagesize) - 1;
+  size_t pagesize = GLRO (dl_pagesize);
   INTERNAL_SIZE_T offset = p->prev_size;
   INTERNAL_SIZE_T size = chunksize (p);
   char *cp;
@@ -2843,7 +2846,7 @@ mremap_chunk (mchunkptr p, size_t new_size)
   assert (((size + offset) & (GLRO (dl_pagesize) - 1)) == 0);
 
   /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
-  new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask;
+  new_size = ALIGN_UP (new_size + offset + SIZE_SZ, pagesize);
 
   /* No need to remap if the number of pages does not change.  */
   if (size + offset == new_size)
@@ -3122,8 +3125,8 @@ __libc_valloc (size_t bytes)
     ptmalloc_init ();
 
   void *address = RETURN_ADDRESS (0);
-  size_t pagesz = GLRO (dl_pagesize);
-  return _mid_memalign (pagesz, bytes, address);
+  size_t pagesize = GLRO (dl_pagesize);
+  return _mid_memalign (pagesize, bytes, address);
 }
 
 void *
@@ -3133,18 +3136,17 @@ __libc_pvalloc (size_t bytes)
     ptmalloc_init ();
 
   void *address = RETURN_ADDRESS (0);
-  size_t pagesz = GLRO (dl_pagesize);
-  size_t page_mask = GLRO (dl_pagesize) - 1;
-  size_t rounded_bytes = (bytes + page_mask) & ~(page_mask);
+  size_t pagesize = GLRO (dl_pagesize);
+  size_t rounded_bytes = ALIGN_UP (bytes, pagesize);
 
   /* Check for overflow.  */
-  if (bytes > SIZE_MAX - 2 * pagesz - MINSIZE)
+  if (bytes > SIZE_MAX - 2 * pagesize - MINSIZE)
     {
       __set_errno (ENOMEM);
       return 0;
     }
 
-  return _mid_memalign (pagesz, rounded_bytes, address);
+  return _mid_memalign (pagesize, rounded_bytes, address);
 }
 
 void *