2601   mchunkptr  top;  member
2653 #define is_initialized(M)  ((M)->top != 0)
3283   if (p != m->dv && p != m->top) {  in do_check_free_chunk()
3289       assert (next == m->top || is_inuse(next));  in do_check_free_chunk()
3445              q != m->top && q->head != FENCEPOST_HEAD) {  in traverse_and_check()
3483   if (m->top != 0) {   /* check top chunk */  in do_check_malloc_state()
3484     do_check_top_chunk(m, m->top);  in do_check_malloc_state()
3487     assert(bin_find(m, m->top) == 0);  in do_check_malloc_state()
3512                q != m->top && q->head != FENCEPOST_HEAD) {  in internal_mallinfo()
3556                q != m->top && q->head != FENCEPOST_HEAD) {  in internal_malloc_stats()
3914   m->top = p;  in init_top()
3944   m->top = m->dv = 0;  in reset_on_error()
3966   if (oldfirst == m->top) {  in prepend_alloc()
3968     m->top = q;  in prepend_alloc()
3996   char* old_top = (char*)m->top;  in add_segment()
4043   check_top_chunk(m, m->top);  in add_segment()
4098     msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top);  in sys_alloc()
4218           segment_holds(sp, m->top)) { /* append */  in sys_alloc()
4220         init_top(m, m->top, m->topsize + tsize);  in sys_alloc()
4243       mchunkptr p = m->top;  in sys_alloc()
4244       mchunkptr r = m->top = chunk_plus_offset(p, nb);  in sys_alloc()
4247       check_top_chunk(m, m->top);  in sys_alloc()
4318       msegmentptr sp = segment_holding(m, (char*)m->top);  in sys_trim()
4355         init_top(m, m->top, m->topsize - released);  in sys_trim()
4356         check_top_chunk(m, m->top);  in sys_trim()
4406       if (next == m->top) {  in dispose_chunk()
4408         m->top = p;  in dispose_chunk()
4672       mchunkptr p = gm->top;  in dlmalloc()
4673       mchunkptr r = gm->top = chunk_plus_offset(p, nb);  in dlmalloc()
4677       check_top_chunk(gm, gm->top);  in dlmalloc()
4754             if (next == fm->top) {  in dlfree()
4756               fm->top = p;  in dlfree()
4851     else if (next == m->top) {  /* extend into top */  in try_realloc_chunk()
4858         m->top = newtop;  in try_realloc_chunk()
5175     mchunkptr top = m->top;  in internal_inspect_all()  local
5199         if (q == top)  in internal_inspect_all()
5453   check_top_chunk(m, m->top);  in init_user_mstate()
5629       mchunkptr p = ms->top;  in mspace_malloc()
5630       mchunkptr r = ms->top = chunk_plus_offset(p, nb);  in mspace_malloc()
5634       check_top_chunk(ms, ms->top);  in mspace_malloc()
5696             if (next == fm->top) {  in mspace_free()
5698               fm->top = p;  in mspace_free()