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Refactor checks to improve codegen.

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This commit is contained in:
Matthew Parkinson
2021-03-17 18:41:56 +00:00
committed by Matthew Parkinson
parent 0983f1837b
commit ed615eade9
4 changed files with 73 additions and 89 deletions
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118
src/mem/alloc.h
View File

@@ -763,16 +763,19 @@ namespace snmalloc
for (size_t i = 0; i < NUM_SMALL_CLASSES; i++)
{
while (!small_fast_free_lists[i].empty())
if (!small_fast_free_lists[i].empty())
{
auto curr = small_fast_free_lists[i].take();
auto head = small_fast_free_lists[i].peek();
auto super = Superslab::get(head);
auto slab = Metaslab::get_slab(head);
do
{
auto curr = small_fast_free_lists[i].take();
small_dealloc_offseted_inner(super, slab, curr, i);
} while (!small_fast_free_lists[i].empty());
Superslab* super = Superslab::get(curr);
Slab* slab = Metaslab::get_slab(curr);
small_dealloc_offseted_inner(super, slab, curr, i);
test(small_classes[i]);
}
test(small_classes[i]);
}
for (auto& medium_class : medium_classes)
@@ -828,10 +831,9 @@ namespace snmalloc
// Destined for my slabs
Superslab* super = Superslab::get(p);
#ifdef CHECK_CLIENT
if (p->trunc_target_id() != (super->get_allocator()->trunc_id()))
error("Detected memory corruption. Potential use-after-free");
#endif
check_client(
p->trunc_target_id() == super->get_allocator()->trunc_id(),
"Detected memory corruption. Potential use-after-free");
void* start = remove_cache_friendly_offset(p, p->sizeclass());
dealloc_not_large_local(super, start, p, p->sizeclass());
@@ -1178,13 +1180,9 @@ namespace snmalloc
SNMALLOC_FAST_PATH void
small_dealloc_unchecked(Superslab* super, void* p, sizeclass_t sizeclass)
{
#ifdef CHECK_CLIENT
uint8_t chunkmap_slab_kind = chunkmap().get(address_cast(p));
if (chunkmap_slab_kind != CMSuperslab)
{
error("Claimed small deallocation is not in a Superslab");
}
#endif
check_client(
chunkmap().get(address_cast(p)) == CMSuperslab,
"Claimed small deallocation is not in a Superslab");
small_dealloc_checked_chunkmap(super, p, sizeclass);
}
@@ -1193,13 +1191,9 @@ namespace snmalloc
Superslab* super, void* p, sizeclass_t sizeclass)
{
Slab* slab = Metaslab::get_slab(p);
#ifdef CHECK_CLIENT
Metaslab& meta = super->get_meta(slab);
if (sizeclass != meta.sizeclass)
{
error("Claimed small deallocation with mismatching size class");
}
#endif
check_client(
sizeclass == super->get_meta(slab).sizeclass,
"Claimed small deallocation with mismatching size class");
small_dealloc_checked_sizeclass(super, slab, p, sizeclass);
}
@@ -1207,12 +1201,9 @@ namespace snmalloc
SNMALLOC_FAST_PATH void small_dealloc_checked_sizeclass(
Superslab* super, Slab* slab, void* p, sizeclass_t sizeclass)
{
#ifdef CHECK_CLIENT
if (!Metaslab::is_start_of_object(&Slab::get_meta(slab), p))
{
error("Not deallocating start of an object");
}
#endif
check_client(
Metaslab::is_start_of_object(&Slab::get_meta(slab), p),
"Not deallocating start of an object");
small_dealloc_start(super, slab, p, sizeclass);
}
@@ -1363,13 +1354,9 @@ namespace snmalloc
void
medium_dealloc_unchecked(Mediumslab* slab, void* p, sizeclass_t sizeclass)
{
#ifdef CHECK_CLIENT
uint8_t chunkmap_slab_kind = chunkmap().get(address_cast(p));
if (chunkmap_slab_kind != CMMediumslab)
{
error("Claimed medium deallocation is not in a Mediumslab");
}
#endif
check_client(
chunkmap().get(address_cast(p)) == CMMediumslab,
"Claimed medium deallocation is not in a Mediumslab");
medium_dealloc_checked_chunkmap(slab, p, sizeclass);
}
@@ -1378,12 +1365,9 @@ namespace snmalloc
void medium_dealloc_checked_chunkmap(
Mediumslab* slab, void* p, sizeclass_t sizeclass)
{
#ifdef CHECK_CLIENT
if (slab->get_sizeclass() != sizeclass)
{
error("Claimed medium deallocation of the wrong sizeclass");
}
#endif
check_client(
slab->get_sizeclass() == sizeclass,
"Claimed medium deallocation of the wrong sizeclass");
medium_dealloc_checked_sizeclass(slab, p, sizeclass);
}
@@ -1392,14 +1376,11 @@ namespace snmalloc
void medium_dealloc_checked_sizeclass(
Mediumslab* slab, void* p, sizeclass_t sizeclass)
{
#ifdef CHECK_CLIENT
if (!is_multiple_of_sizeclass(
sizeclass_to_size(sizeclass),
pointer_diff(p, pointer_offset(slab, SUPERSLAB_SIZE))))
{
error("Not deallocating start of an object");
}
#endif
check_client(
is_multiple_of_sizeclass(
sizeclass_to_size(sizeclass),
pointer_diff(p, pointer_offset(slab, SUPERSLAB_SIZE))),
"Not deallocating start of an object");
medium_dealloc_start(slab, p, sizeclass);
}
@@ -1482,37 +1463,22 @@ namespace snmalloc
void large_dealloc_unchecked(void* p, size_t size)
{
size_t claimed_chunkmap_slab_kind = bits::next_pow2_bits(size);
uint8_t chunkmap_slab_kind;
uint8_t claimed_chunkmap_slab_kind =
static_cast<uint8_t>(bits::next_pow2_bits(size));
#ifdef CHECK_CLIENT
chunkmap_slab_kind = chunkmap().get(address_cast(p));
if (chunkmap_slab_kind < CMLargeMin)
{
error("Claimed large deallocation is not in a large slab");
}
if (chunkmap_slab_kind != claimed_chunkmap_slab_kind)
{
error("Claimed large deallocation with wrong size class");
}
#else
// Trusting sort, aren't we?
chunkmap_slab_kind = static_cast<uint8_t>(claimed_chunkmap_slab_kind);
#endif
check_client(
chunkmap().get(address_cast(p)) == claimed_chunkmap_slab_kind,
"Claimed large deallocation with wrong size class");
large_dealloc_checked_sizeclass(p, size, chunkmap_slab_kind);
large_dealloc_checked_sizeclass(p, size, claimed_chunkmap_slab_kind);
}
void large_dealloc_checked_sizeclass(
void* p, size_t size, uint8_t chunkmap_slab_kind)
{
#ifdef CHECK_CLIENT
Superslab* super = Superslab::get(p);
if (address_cast(super) != address_cast(p))
{
error("Not deallocating start of an object");
}
#endif
check_client(
address_cast(Superslab::get(p)) == address_cast(p),
"Not deallocating start of an object");
SNMALLOC_ASSERT(bits::one_at_bit(chunkmap_slab_kind) >= SUPERSLAB_SIZE);
large_dealloc_start(p, size, chunkmap_slab_kind);

16
src/mem/allocconfig.h
View File

@@ -8,6 +8,22 @@ namespace snmalloc
// calling the API correctly.
#if !defined(NDEBUG) && !defined(CHECK_CLIENT)
# define CHECK_CLIENT
#endif
SNMALLOC_FAST_PATH void check_client_impl(bool test, const char* const str)
{
#ifdef CHECK_CLIENT
if (unlikely(!test))
error(str);
#else
UNUSED(test);
UNUSED(str);
#endif
}
#ifdef CHECK_CLIENT
# define check_client(test, str) check_client_impl(test, str)
#else
# define check_client(test, str)
#endif
// 0 intermediate bits results in power of 2 small allocs. 1 intermediate

23
src/mem/freelist.h
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@@ -139,10 +139,9 @@ namespace snmalloc
# ifndef NDEBUG
if (next != nullptr)
{
if (unlikely(different_slab(prev, next)))
{
error("Heap corruption - free list corrupted!");
}
check_client(
!different_slab(prev, next),
"Heap corruption - free list corrupted!");
}
# endif
prev = address_cast(curr);
@@ -162,10 +161,8 @@ namespace snmalloc
void move_next()
{
#ifdef CHECK_CLIENT
if (unlikely(different_slab(prev, curr)))
{
error("Heap corruption - free list corrupted!");
}
check_client(
!different_slab(prev, curr), "Heap corruption - free list corrupted!");
#endif
update_cursor(curr->read_next(get_prev()));
}
@@ -221,6 +218,14 @@ namespace snmalloc
return front.get_curr() == nullptr;
}
/**
* Returns current head without affecting the iterator.
*/
void* peek()
{
return front.get_curr();
}
/**
* Moves the iterator on, and returns the current value.
*/
@@ -258,7 +263,7 @@ namespace snmalloc
*/
void* peek_head()
{
return front.get_curr();
return peek();
}
/**

5
src/mem/slab.h
View File

@@ -81,10 +81,7 @@ namespace snmalloc
dealloc_fast(Slab* self, Superslab* super, void* p)
{
Metaslab& meta = super->get_meta(self);
#ifdef CHECK_CLIENT
if (meta.is_unused())
error("Detected potential double free.");
#endif
SNMALLOC_ASSERT(!meta.is_unused());
if (unlikely(meta.return_object()))
return false;