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LibC: Increase minimum alignment for malloc() to 16 bytes

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This is required to make SSE instructions work when building with
Clang. Apparently Clang uses SSE instructions where GCC didn't so
we didn't previously run into this problem.
This commit is contained in:
Gunnar Beutner 2021-07-13 14:29:17 +02:00 • committed by Andreas Kling
parent 3b81ba7c4f
commit 5f3773b715
1 changed files with 3 additions and 3 deletions
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6
Userland/Libraries/LibC/mallocdefs.h
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@ -16,13 +16,13 @@
#define PAGE_ROUND_UP(x) ((((size_t)(x)) + PAGE_SIZE - 1) & (~(PAGE_SIZE - 1))) #define PAGE_ROUND_UP(x) ((((size_t)(x)) + PAGE_SIZE - 1) & (~(PAGE_SIZE - 1)))
static constexpr unsigned short size_classes[] = { 8, 16, 32, 64, 128, 256, 504, 1016, 2032, 4088, 8184, 16376, 32752, 0 }; static constexpr unsigned short size_classes[] = { 16, 32, 64, 128, 256, 496, 1008, 2032, 4080, 8176, 16368, 32752, 0 };
static constexpr size_t num_size_classes = (sizeof(size_classes) / sizeof(unsigned short)) - 1; static constexpr size_t num_size_classes = (sizeof(size_classes) / sizeof(unsigned short)) - 1;
consteval bool check_size_classes_alignment() consteval bool check_size_classes_alignment()
{ {
for (size_t i = 0; i < num_size_classes; i++) { for (size_t i = 0; i < num_size_classes; i++) {
if ((size_classes[i] % 8) != 0) if ((size_classes[i] % 16) != 0)
return false; return false;
} }
return true; return true;
@ -63,7 +63,7 @@ struct ChunkedBlock : public CommonHeader {
size_t m_next_lazy_freelist_index { 0 }; size_t m_next_lazy_freelist_index { 0 };
FreelistEntry* m_freelist { nullptr }; FreelistEntry* m_freelist { nullptr };
size_t m_free_chunks { 0 }; size_t m_free_chunks { 0 };
[[gnu::aligned(8)]] unsigned char m_slot[0]; [[gnu::aligned(16)]] unsigned char m_slot[0];
void* chunk(size_t index) void* chunk(size_t index)
{ {