MIRROR: javascript for 🐜's, a tiny runtime with big ambitions
add hint to mmap
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include/arena.h
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include/arena.h
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#define ARENA_GROW_INCREMENT (8ULL * 1024 * 1024)
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#define ANT_CLOSURE_ARENA_MAX (2ULL * 1024 * 1024 * 1024)
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// preferred base for mmap on platforms where the kernel may hand out
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// addresses above the 47-bit NaN-boxing ceiling. We pick 0x100000000
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// inside the 47-bit range and above the typical text/data segments.
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#define ANT_MMAP_HINT ((void *)0x100000000ULL)
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typedef struct {
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uint8_t *base;
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size_t committed;
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#else
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static inline void *ant_arena_reserve(size_t max_size) {
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void *p = mmap(NULL, max_size, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
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void *p = mmap(ANT_MMAP_HINT, max_size, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
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if (p == MAP_FAILED) return NULL;
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if ((uintptr_t)p >> 47) {
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munmap(p, max_size);
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p = mmap(NULL, max_size, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
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if (p == MAP_FAILED) return NULL;
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}
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return mantissa_chk(p, "mmap");
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}
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···
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}
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static inline void *ant_os_alloc(size_t size) {
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void *p = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
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return (p == MAP_FAILED) ? NULL : p;
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void *p = mmap(ANT_MMAP_HINT, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
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if (p == MAP_FAILED) return NULL;
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if ((uintptr_t)p >> 47) {
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munmap(p, size);
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p = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
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if (p == MAP_FAILED) return NULL;
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}
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return mantissa_chk(p, "mmap");
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}
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static inline int ant_arena_decommit(void *base, size_t old_size, size_t new_size) {