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Merge pull request #32 from jedisct1/wasm

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Port to WebAssembly
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Daan 2019-07-15 11:03:46 -07:00 • committed by GitHub
commit ad45dbf0e5
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 51 additions and 1 deletions
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30
src/os.c
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@ -16,6 +16,8 @@ terms of the MIT license. A copy of the license can be found in the file
#if defined(_WIN32)
#include <windows.h>
#elif defined(__wasi__)
// stdlib.h is all we need, and has already been included in mimalloc.h
#else
#include <sys/mman.h> // mmap
#include <unistd.h> // sysconf
@ -136,6 +138,11 @@ void _mi_os_init(void) {
}
}
}
#elif defined(__wasi__)
void _mi_os_init() {
os_page_size = 0x10000; // WebAssembly has a fixed page size: 64KB
os_alloc_granularity = 16;
}
#else
void _mi_os_init() {
// get the page size
@ -161,6 +168,8 @@ static bool mi_os_mem_free(void* addr, size_t size, mi_stats_t* stats)
bool err = false;
#if defined(_WIN32)
err = (VirtualFree(addr, 0, MEM_RELEASE) == 0);
#elif defined(__wasi__)
err = 0; // WebAssembly's heap cannot be shrunk
#else
err = (munmap(addr, size) == -1);
#endif
@ -216,6 +225,19 @@ static void* mi_win_virtual_alloc(void* addr, size_t size, size_t try_alignment,
return p;
}
#elif defined(__wasi__)
static void* mi_wasm_heap_grow(size_t size, size_t try_alignment) {
uintptr_t base = __builtin_wasm_memory_size(0) * os_page_size;
uintptr_t aligned_base = _mi_align_up(base, (uintptr_t) try_alignment);
size_t alloc_size = aligned_base - base + size;
mi_assert(alloc_size >= size);
if (alloc_size < size) return NULL;
if (__builtin_wasm_memory_grow(0, alloc_size / os_page_size) == SIZE_MAX) {
errno = ENOMEM;
return NULL;
}
return (void*) aligned_base;
}
#else
static void* mi_unix_mmap(size_t size, size_t try_alignment, int protect_flags) {
void* p = NULL;
@ -272,6 +294,8 @@ static void* mi_os_mem_alloc(size_t size, size_t try_alignment, bool commit, mi_
int flags = MEM_RESERVE;
if (commit) flags |= MEM_COMMIT;
p = mi_win_virtual_alloc(NULL, size, try_alignment, flags);
#elif defined(__wasi__)
p = mi_wasm_heap_grow(size, try_alignment);
#else
int protect_flags = (commit ? (PROT_WRITE | PROT_READ) : PROT_NONE);
p = mi_unix_mmap(size, try_alignment, protect_flags);
@ -434,6 +458,8 @@ static bool mi_os_commitx(void* addr, size_t size, bool commit, bool conservativ
BOOL ok = VirtualFree(start, csize, MEM_DECOMMIT);
err = (ok ? 0 : GetLastError());
}
#elif defined(__wasi__)
// WebAssembly guests can't control memory protection
#else
err = mprotect(start, csize, (commit ? (PROT_READ | PROT_WRITE) : PROT_NONE));
#endif
@ -496,6 +522,8 @@ static bool mi_os_resetx(void* addr, size_t size, bool reset, mi_stats_t* stats)
advice = MADV_DONTNEED;
err = madvise(start, csize, advice);
}
#elif defined(__wasi__)
int err = 0;
#else
int err = madvise(start, csize, MADV_DONTNEED);
#endif
@ -543,6 +571,8 @@ static bool mi_os_protectx(void* addr, size_t size, bool protect) {
DWORD oldprotect = 0;
BOOL ok = VirtualProtect(start, csize, protect ? PAGE_NOACCESS : PAGE_READWRITE, &oldprotect);
err = (ok ? 0 : GetLastError());
#elif defined(__wasi__)
err = 0;
#else
err = mprotect(start, csize, protect ? PROT_NONE : (PROT_READ | PROT_WRITE));
#endif