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Make emacs not croak when editing dlmalloc

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Justine Tunney 2022-06-09 17:45:30 -07:00
parent 3c7ae0fc72
commit fa1e8a3e65
21 changed files with 3019 additions and 2985 deletions
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79
third_party/dlmalloc/directmap.inc vendored Normal file
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// clang-format off
/* ----------------------- Direct-mmapping chunks ----------------------- */
/*
Directly mmapped chunks are set up with an offset to the start of
the mmapped region stored in the prev_foot field of the chunk. This
allows reconstruction of the required argument to MUNMAP when freed,
and also allows adjustment of the returned chunk to meet alignment
requirements (especially in memalign).
*/
/* Malloc using mmap */
static void* mmap_alloc(mstate m, size_t nb) {
size_t mmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
if (m->footprint_limit != 0) {
size_t fp = m->footprint + mmsize;
if (fp <= m->footprint || fp > m->footprint_limit)
return 0;
}
if (mmsize > nb) { /* Check for wrap around 0 */
char* mm = (char*)(dlmalloc_requires_more_vespene_gas(mmsize));
if (mm != CMFAIL) {
size_t offset = align_offset(chunk2mem(mm));
size_t psize = mmsize - offset - MMAP_FOOT_PAD;
mchunkptr p = (mchunkptr)(mm + offset);
p->prev_foot = offset;
p->head = psize;
mark_inuse_foot(m, p, psize);
chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0;
if (m->least_addr == 0 || mm < m->least_addr)
m->least_addr = mm;
if ((m->footprint += mmsize) > m->max_footprint)
m->max_footprint = m->footprint;
assert(is_aligned(chunk2mem(p)));
check_mmapped_chunk(m, p);
return chunk2mem(p);
}
}
return 0;
}
/* Realloc using mmap */
static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb, int flags) {
size_t oldsize = chunksize(oldp);
(void)flags; /* placate people compiling -Wunused */
if (is_small(nb)) /* Can't shrink mmap regions below small size */
return 0;
/* Keep old chunk if big enough but not too big */
if (oldsize >= nb + SIZE_T_SIZE &&
(oldsize - nb) <= (mparams.granularity << 1))
return oldp;
else {
size_t offset = oldp->prev_foot;
size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
size_t newmmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
char* cp = (char*)CALL_MREMAP((char*)oldp - offset,
oldmmsize, newmmsize, flags);
if (cp != CMFAIL) {
mchunkptr newp = (mchunkptr)(cp + offset);
size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
newp->head = psize;
mark_inuse_foot(m, newp, psize);
chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0;
if (cp < m->least_addr)
m->least_addr = cp;
if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
m->max_footprint = m->footprint;
check_mmapped_chunk(m, newp);
return newp;
}
}
return 0;
}