From 09f5e1635ae75de077c5307d02fdbefc4b0c7144 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Sun, 31 Dec 2000 07:39:50 +0000 Subject: Update. 2000-12-28 Wolfram Gloger * malloc/malloc.c (MALLOC_COPY): Handle case if source and destination overlap. Assume dest is always below source if overlapping. --- malloc/malloc.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-) (limited to 'malloc/malloc.c') diff --git a/malloc/malloc.c b/malloc/malloc.c index 187c814..1ac3b5d 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -423,11 +423,12 @@ Void_t* memmove(); #endif #endif -#if USE_MEMCPY - /* The following macros are only invoked with (2n+1)-multiples of INTERNAL_SIZE_T units, with a positive integer n. This is exploited - for fast inline execution when n is small. */ + for fast inline execution when n is small. If the regions to be + copied do overlap, the destination lies always _below_ the source. */ + +#if USE_MEMCPY #define MALLOC_ZERO(charp, nbytes) \ do { \ @@ -446,7 +447,9 @@ do { \ } else memset((charp), 0, mzsz); \ } while(0) -#define MALLOC_COPY(dest,src,nbytes) \ +/* If the regions overlap, dest is always _below_ src. */ + +#define MALLOC_COPY(dest,src,nbytes,overlap) \ do { \ INTERNAL_SIZE_T mcsz = (nbytes); \ if(mcsz <= 9*sizeof(mcsz)) { \ @@ -461,12 +464,12 @@ do { \ *mcdst++ = *mcsrc++; \ *mcdst++ = *mcsrc++; \ *mcdst = *mcsrc ; \ - } else memcpy(dest, src, mcsz); \ + } else if(overlap) \ + memmove(dest, src, mcsz); \ + else \ + memcpy(dest, src, mcsz); \ } while(0) -#define MALLOC_MEMMOVE(dest,src,nbytes) \ - memmove(dest, src, mcsz) - #else /* !USE_MEMCPY */ /* Use Duff's device for good zeroing/copying performance. */ @@ -488,7 +491,9 @@ do { \ } \ } while(0) -#define MALLOC_COPY(dest,src,nbytes) \ +/* If the regions overlap, dest is always _below_ src. */ + +#define MALLOC_COPY(dest,src,nbytes,overlap) \ do { \ INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \ INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \ @@ -3255,7 +3260,7 @@ Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes; /* Must alloc, copy, free. */ newmem = mALLOc(bytes); if (newmem == 0) return 0; /* propagate failure */ - MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ); + MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ, 0); munmap_chunk(oldp); return newmem; } @@ -3370,7 +3375,8 @@ arena* ar_ptr; mchunkptr oldp; INTERNAL_SIZE_T oldsize, nb; unlink(prev, bck, fwd); newp = prev; newsize += prevsize + nextsize; - MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize); + MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize, + 1); top(ar_ptr) = chunk_at_offset(newp, nb); set_head(top(ar_ptr), (newsize - nb) | PREV_INUSE); set_head_size(newp, nb); @@ -3385,7 +3391,7 @@ arena* ar_ptr; mchunkptr oldp; INTERNAL_SIZE_T oldsize, nb; unlink(prev, bck, fwd); newp = prev; newsize += nextsize + prevsize; - MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize); + MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize, 1); goto split; } } @@ -3396,7 +3402,7 @@ arena* ar_ptr; mchunkptr oldp; INTERNAL_SIZE_T oldsize, nb; unlink(prev, bck, fwd); newp = prev; newsize += prevsize; - MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize); + MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize, 1); goto split; } } @@ -3436,7 +3442,7 @@ arena* ar_ptr; mchunkptr oldp; INTERNAL_SIZE_T oldsize, nb; } /* Otherwise copy, free, and exit */ - MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize); + MALLOC_COPY(BOUNDED_N(chunk2mem(newp), oldsize), oldmem, oldsize, 0); chunk_free(ar_ptr, oldp); return newp; } @@ -4605,7 +4611,7 @@ realloc_check(oldmem, bytes, caller) newp = (top_check() >= 0) ? chunk_alloc(&main_arena, nb) : NULL; if (newp) { MALLOC_COPY(BOUNDED_N(chunk2mem(newp), nb), - oldmem, oldsize - 2*SIZE_SZ); + oldmem, oldsize - 2*SIZE_SZ, 0); munmap_chunk(oldp); } } -- cgit v1.1