com php-src: fixed zend_hash_init() when the lzcn t instruction isn't supported: Zend/zend_hash.c

Commit: 8e3764e287ceb3c954dfd866dc72c9530907bef7 Author: Anatol Belski <ab@php.net> Wed, 14 Jan 2015 12:29:50 +0100 Parents: ade7a410403d7ec3fc1579bee3b890b1ce549eec Branches: master Link: http://git.php.net/?p=php-src.git;a=commitdiff;h=8e3764e287ceb3c954dfd866dc72c9530907bef7 Log: fixed zend_hash_init() when the lzcnt instruction isn't supported Changed paths: M Zend/zend_hash.c Diff: diff --git a/Zend/zend_hash.c b/Zend/zend_hash.c index fd0d27f..e496e58 100644 --- a/Zend/zend_hash.c +++ b/Zend/zend_hash.c @@ -101,25 +101,24 @@ static const uint32_t uninitialized_bucket = {INVALID_IDX}; ZEND_API void _zend_hash_init(HashTable *ht, uint32_t nSize, dtor_func_t pDestructor, zend_bool persistent ZEND_FILE_LINE_DC) { +#if defined(ZEND_WIN32) + unsigned long index; +#endif /* Use big enough power of 2 */ -#if defined(PHP_WIN32) && !defined(__clang__) - if (nSize <= 8) { - ht->nTableSize = 8; - } else if (nSize >= 0x80000000) { - /* prevent overflow */ - ht->nTableSize = 0x80000000; - } else { - ht->nTableSize = 1U << __lzcnt(nSize); - if (ht->nTableSize < nSize) { - ht->nTableSize <<= 1; - } - } -#else /* size should be between 8 and 0x80000000 */ nSize = (nSize <= 8 ? 8 : (nSize >= 0x80000000 ? 0x80000000 : nSize)); -# if defined(__GNUC__) + +#if defined(ZEND_WIN32) + if (BitScanReverse(&index, nSize - 1)) { + ht->nTableSize = 0x2 << ((31 - index) ^ 0x1f); + } else { + /* nSize is ensured to be in the valid range, fall back to it + rather than using an undefined bis scan result. */ + ht->nTableSize = nSize; + } +#elif defined(__GNUC__) ht->nTableSize = 0x2 << (__builtin_clz(nSize - 1) ^ 0x1f); -# else +#else nSize -= 1; nSize |= (nSize >> 1); nSize |= (nSize >> 2); @@ -127,7 +126,6 @@ ZEND_API void _zend_hash_init(HashTable *ht, uint32_t nSize, dtor_func_t pDestru nSize |= (nSize >> 8); nSize |= (nSize >> 16); ht->nTableSize = nSize + 1; -# endif #endif ht->nTableMask = 0;