Function _memory_map

vm/ByteCodeTranslator/src/rpmalloc.c:1527–1565

Map new pages to virtual memory

//! Map new pages to virtual memory
static void*
_memory_map(size_t page_count) {
	size_t total_size = page_count * PAGE_SIZE;
	void* pages_ptr = 0;

#if ENABLE_STATISTICS
	atomic_add32(&_mapped_pages, (int32_t)page_count);
	atomic_add32(&_mapped_total, (int32_t)page_count);
#endif

#ifdef PLATFORM_WINDOWS
	pages_ptr = VirtualAlloc(0, total_size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
#else
	//mmap lacks a way to set 64KiB address granularity, implement it locally
	intptr_t incr = (intptr_t)total_size / (intptr_t)SPAN_ADDRESS_GRANULARITY;
	if (total_size % SPAN_ADDRESS_GRANULARITY)
		++incr;
	do {
		void* base_addr = (void*)(uintptr_t)atomic_exchange_and_add64(&_memory_addr,
		                  (incr * (intptr_t)SPAN_ADDRESS_GRANULARITY));
		pages_ptr = mmap(base_addr, total_size, PROT_READ | PROT_WRITE,
		                 MAP_PRIVATE | MAP_ANONYMOUS | MAP_UNINITIALIZED, -1, 0);
		if (pages_ptr != MAP_FAILED) {
			if (pages_ptr != base_addr) {
				void* new_base = (void*)((uintptr_t)pages_ptr & SPAN_MASK);
				atomic_store64(&_memory_addr, (int64_t)((uintptr_t)new_base) +
							   ((incr + 1) * (intptr_t)SPAN_ADDRESS_GRANULARITY));
				atomic_thread_fence_release();
			}
			if (!((uintptr_t)pages_ptr & ~SPAN_MASK))
				break;
			munmap(pages_ptr, total_size);
		}
	}
	while (1);
#endif

	return pages_ptr;
}

//! Unmap pages from virtual memory
static void