[PATCH] Fix realloc

[Jakub Jelinek]

Hi!

realloc was using memcpy even for copies where source and destination might
overlap. Found with new alphaev6 memcpy during make check. Maybe we should sometimes
try using
void *memcpy (void *dst, const void *src, size_t len)
{
  memset(dst, 0xaf, len);
  return memmove(dst, src, len);
}
and see what crashes...

2000-12-27  Jakub Jelinek  <jakub@redhat.com>

	* malloc/malloc.c (memmove): Add prototypes.
	(MALLOC_MEMMOVE): Define.
	(chunk_realloc): Use it instead of MALLOC_COPY if source and
	destination might overlap.

--- libc/malloc/malloc.c.jj	Fri Sep 29 12:56:58 2000
+++ libc/malloc/malloc.c	Wed Dec 27 17:58:28 2000
@@ -415,9 +415,11 @@ extern "C" {
 #if __STD_C
 void* memset(void*, int, size_t);
 void* memcpy(void*, const void*, size_t);
+void* memmove(void*, const void*, size_t);
 #else
 Void_t* memset();
 Void_t* memcpy();
+Void_t* memmove();
 #endif
 #endif
 
@@ -462,6 +464,24 @@ do {                                    
   } else memcpy(dest, src, mcsz);                                             \
 } while(0)
 
+#define MALLOC_MEMMOVE(dest,src,nbytes)                                       \
+do {                                                                          \
+  INTERNAL_SIZE_T mcsz = (nbytes);                                            \
+  if(mcsz <= 9*sizeof(mcsz)) {                                                \
+    INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src);                        \
+    INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest);                       \
+    if(mcsz >= 5*sizeof(mcsz)) {     *mcdst++ = *mcsrc++;                     \
+                                     *mcdst++ = *mcsrc++;                     \
+      if(mcsz >= 7*sizeof(mcsz)) {   *mcdst++ = *mcsrc++;                     \
+                                     *mcdst++ = *mcsrc++;                     \
+        if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++;                     \
+                                     *mcdst++ = *mcsrc++; }}}                 \
+                                     *mcdst++ = *mcsrc++;                     \
+                                     *mcdst++ = *mcsrc++;                     \
+                                     *mcdst   = *mcsrc  ;                     \
+  } else memmove(dest, src, mcsz);                                            \
+} while(0)
+
 #else /* !USE_MEMCPY */
 
 /* Use Duff's device for good zeroing/copying performance. */
@@ -501,6 +521,8 @@ do {                                    
   }                                                                           \
 } while(0)
 
+#define MALLOC_MEMMOVE(dest,src,nbytes)
+
 #endif
 
 
@@ -3365,7 +3387,7 @@ arena* ar_ptr; mchunkptr oldp; INTERNAL_
             unlink(prev, bck, fwd);
             newp = prev;
             newsize += prevsize + nextsize;
-            MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize);
+            MALLOC_MEMMOVE(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize);
             top(ar_ptr) = chunk_at_offset(newp, nb);
             set_head(top(ar_ptr), (newsize - nb) | PREV_INUSE);
             set_head_size(newp, nb);
@@ -3380,7 +3402,7 @@ arena* ar_ptr; mchunkptr oldp; INTERNAL_
           unlink(prev, bck, fwd);
           newp = prev;
           newsize += nextsize + prevsize;
-          MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize);
+          MALLOC_MEMMOVE(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize);
           goto split;
         }
       }
@@ -3391,7 +3413,7 @@ arena* ar_ptr; mchunkptr oldp; INTERNAL_
         unlink(prev, bck, fwd);
         newp = prev;
         newsize += prevsize;
-        MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize);
+        MALLOC_MEMMOVE(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize);
         goto split;
       }
     }

	Jakub