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In Runningprocess wissen wir bereits, dass der Code eine lexikalische Analyse, Syntaxanalyse, Kompilierung und Ausführung von vier Hauptschritten durchlaufen muss
PHP 8 befindet sich in der Kompilierungsphase (wenn der abstrakte AST-Syntaxbaum in Opcode kompiliert wird) und erstellt eine Array-Konstante. Diese Array-Konstante wird, ebenso wie numerische Konstanten und String-Konstanten, während der Kompilierungsphase bestimmt und Speicher zugewiesen. Die Initialisierung des Arrays erfolgt also während der Kompilierungsphase.
Der Array-Initialisierungscodeteil von PHP lautet wie folgt:
//如果开启zend_debug #if !ZEND_DEBUG && defined(HAVE_BUILTIN_CONSTANT_P) # define zend_new_array(size) \ (__builtin_constant_p(size) ? \ ((((uint32_t)(size)) <= HT_MIN_SIZE) ? \ _zend_new_array_0() \ //走 _zend_new_array_0 : \ _zend_new_array((size)) \ ) \ : \ _zend_new_array((size)) \ ) #else //没有开启 也就是一般模式 走 _zend_new_array # define zend_new_array(size) \ _zend_new_array(size) #endif ZEND_API void ZEND_FASTCALL _zend_hash_init(HashTable *ht, uint32_t nSize, dtor_func_t pDestructor, zend_bool persistent) { _zend_hash_init_int(ht, nSize, pDestructor, persistent); } ZEND_API HashTable* ZEND_FASTCALL _zend_new_array_0(void) { //分配内存空间 HashTable *ht = emalloc(sizeof(HashTable)); //初始化 _zend_hash_init_int(ht, HT_MIN_SIZE, ZVAL_PTR_DTOR, 0); return ht; } //初始化方法 static zend_always_inline void _zend_hash_init_int(HashTable *ht, uint32_t nSize, dtor_func_t pDestructor, zend_bool persistent) { GC_SET_REFCOUNT(ht, 1); GC_TYPE_INFO(ht) = GC_ARRAY | (persistent ? ((GC_PERSISTENT|GC_NOT_COLLECTABLE) << GC_FLAGS_SHIFT) : 0); HT_FLAGS(ht) = HASH_FLAG_UNINITIALIZED; ht->nTableMask = HT_MIN_MASK; HT_SET_DATA_ADDR(ht, &uninitialized_bucket); ht->nNumUsed = 0; ht->nNumOfElements = 0; ht->nInternalPointer = 0; ht->nNextFreeElement = ZEND_LONG_MIN; ht->pDestructor = pDestructor; ht->nTableSize = zend_hash_check_size(nSize); } //初始化 bucket 也就是 ardata ZEND_API void ZEND_FASTCALL zend_hash_real_init(HashTable *ht, zend_bool packed) { IS_CONSISTENT(ht); HT_ASSERT_RC1(ht); //调用 zend_hash_real_init_ex方法 zend_hash_real_init_ex(ht, packed); } //zend_hash_real_init_ex方法 static zend_always_inline void zend_hash_real_init_ex(HashTable *ht, bool packed) { HT_ASSERT_RC1(ht); ZEND_ASSERT(HT_FLAGS(ht) & HASH_FLAG_UNINITIALIZED); if (packed) { //如果是packed_array zend_hash_real_init_packed_ex(ht); } else { //如果是 hash_array zend_hash_real_init_mixed_ex(ht); } } //paced_array 初始化bucket 的代码 static zend_always_inline void zend_hash_real_init_packed_ex(HashTable *ht) { void *data; if (UNEXPECTED(GC_FLAGS(ht) & IS_ARRAY_PERSISTENT)) { data = pemalloc(HT_SIZE_EX(ht->nTableSize, HT_MIN_MASK), 1); } else if (EXPECTED(ht->nTableSize == HT_MIN_SIZE)) { data = emalloc(HT_SIZE_EX(HT_MIN_SIZE, HT_MIN_MASK)); } else { data = emalloc(HT_SIZE_EX(ht->nTableSize, HT_MIN_MASK)); } HT_SET_DATA_ADDR(ht, data); /* Don't overwrite iterator count. */ ht->u.v.flags = HASH_FLAG_PACKED | HASH_FLAG_STATIC_KEYS; HT_HASH_RESET_PACKED(ht); } //hash_array 初始化bucket的代码 static zend_always_inline void zend_hash_real_init_mixed_ex(HashTable *ht) { void *data; uint32_t nSize = ht->nTableSize; if (UNEXPECTED(GC_FLAGS(ht) & IS_ARRAY_PERSISTENT)) { data = pemalloc(HT_SIZE_EX(nSize, HT_SIZE_TO_MASK(nSize)), 1); } else if (EXPECTED(nSize == HT_MIN_SIZE)) { data = emalloc(HT_SIZE_EX(HT_MIN_SIZE, HT_SIZE_TO_MASK(HT_MIN_SIZE))); ht->nTableMask = HT_SIZE_TO_MASK(HT_MIN_SIZE); HT_SET_DATA_ADDR(ht, data); /* Don't overwrite iterator count. */ ht->u.v.flags = HASH_FLAG_STATIC_KEYS; #ifdef __SSE2__ do { __m128i xmm0 = _mm_setzero_si128(); xmm0 = _mm_cmpeq_epi8(xmm0, xmm0); _mm_storeu_si128((__m128i*)&HT_HASH_EX(data, 0), xmm0); _mm_storeu_si128((__m128i*)&HT_HASH_EX(data, 4), xmm0); _mm_storeu_si128((__m128i*)&HT_HASH_EX(data, 8), xmm0); _mm_storeu_si128((__m128i*)&HT_HASH_EX(data, 12), xmm0); } while (0); #elif defined(__aarch64__) do { int32x4_t t = vdupq_n_s32(-1); vst1q_s32((int32_t*)&HT_HASH_EX(data, 0), t); vst1q_s32((int32_t*)&HT_HASH_EX(data, 4), t); vst1q_s32((int32_t*)&HT_HASH_EX(data, 8), t); vst1q_s32((int32_t*)&HT_HASH_EX(data, 12), t); } while (0); #else HT_HASH_EX(data, 0) = -1; HT_HASH_EX(data, 1) = -1; HT_HASH_EX(data, 2) = -1; HT_HASH_EX(data, 3) = -1; HT_HASH_EX(data, 4) = -1; HT_HASH_EX(data, 5) = -1; HT_HASH_EX(data, 6) = -1; HT_HASH_EX(data, 7) = -1; HT_HASH_EX(data, 8) = -1; HT_HASH_EX(data, 9) = -1; HT_HASH_EX(data, 10) = -1; HT_HASH_EX(data, 11) = -1; HT_HASH_EX(data, 12) = -1; HT_HASH_EX(data, 13) = -1; HT_HASH_EX(data, 14) = -1; HT_HASH_EX(data, 15) = -1; #endif return; } else { data = emalloc(HT_SIZE_EX(nSize, HT_SIZE_TO_MASK(nSize))); } ht->nTableMask = HT_SIZE_TO_MASK(nSize); HT_SET_DATA_ADDR(ht, data); HT_FLAGS(ht) = HASH_FLAG_STATIC_KEYS; HT_HASH_RESET(ht); } //数组赋值和更新值 static zend_always_inline zval *_zend_hash_index_add_or_update_i(HashTable *ht, zend_ulong h, zval *pData, uint32_t flag) { uint32_t nIndex; uint32_t idx; Bucket *p; IS_CONSISTENT(ht); HT_ASSERT_RC1(ht); if ((flag & HASH_ADD_NEXT) && h == ZEND_LONG_MIN) { h = 0; } if (HT_FLAGS(ht) & HASH_FLAG_PACKED) { if (h < ht->nNumUsed) { p = ht->arData + h; if (Z_TYPE(p->val) != IS_UNDEF) { replace: if (flag & HASH_ADD) { return NULL; } if (ht->pDestructor) { ht->pDestructor(&p->val); } ZVAL_COPY_VALUE(&p->val, pData); return &p->val; } else { /* we have to keep the order :( */ goto convert_to_hash; } } else if (EXPECTED(h < ht->nTableSize)) { add_to_packed: p = ht->arData + h; /* incremental initialization of empty Buckets */ if ((flag & (HASH_ADD_NEW|HASH_ADD_NEXT)) != (HASH_ADD_NEW|HASH_ADD_NEXT)) { if (h > ht->nNumUsed) { Bucket *q = ht->arData + ht->nNumUsed; while (q != p) { ZVAL_UNDEF(&q->val); q++; } } } ht->nNextFreeElement = ht->nNumUsed = h + 1; goto add; } else if ((h >> 1) < ht->nTableSize && (ht->nTableSize >> 1) < ht->nNumOfElements) { zend_hash_packed_grow(ht); goto add_to_packed; } else { if (ht->nNumUsed >= ht->nTableSize) { ht->nTableSize += ht->nTableSize; } convert_to_hash: zend_hash_packed_to_hash(ht); } } else if (HT_FLAGS(ht) & HASH_FLAG_UNINITIALIZED) { if (h < ht->nTableSize) { zend_hash_real_init_packed_ex(ht); goto add_to_packed; } zend_hash_real_init_mixed(ht); } else { if ((flag & HASH_ADD_NEW) == 0 || ZEND_DEBUG) { p = zend_hash_index_find_bucket(ht, h); if (p) { ZEND_ASSERT((flag & HASH_ADD_NEW) == 0); goto replace; } } ZEND_HASH_IF_FULL_DO_RESIZE(ht);/* If the Hash table is full, resize it */ } idx = ht->nNumUsed++; nIndex = h | ht->nTableMask; p = ht->arData + idx; Z_NEXT(p->val) = HT_HASH(ht, nIndex); HT_HASH(ht, nIndex) = HT_IDX_TO_HASH(idx); if ((zend_long)h >= ht->nNextFreeElement) { ht->nNextFreeElement = (zend_long)h < ZEND_LONG_MAX ? h + 1 : ZEND_LONG_MAX; } add: ht->nNumOfElements++; p->h = h; p->key = NULL; ZVAL_COPY_VALUE(&p->val, pData); return &p->val; }
_zend_hash_init_int Das Flussdiagramm lautet wie folgt: Flussdiagramm der Methode_zend_hash_init_int (Initialisierungs-Hash)
Schritt 2: Jedes Feld der HashTable-Struktur initialisieren
zend_hash_real_init_packed_ex (Bucket-Initialisierungsflussdiagramm, wenn gepacktes_Array)
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