[cfe-commits] [libcxx] r146329 - in /libcxx/trunk: CREDITS.TXT include/memory include/string
Howard Hinnant
hhinnant at apple.com
Sat Dec 10 12:28:56 PST 2011
Author: hhinnant
Date: Sat Dec 10 14:28:56 2011
New Revision: 146329
URL: http://llvm.org/viewvc/llvm-project?rev=146329&view=rev
Log:
Installation of CityHash by Craig Silverstein
Modified:
libcxx/trunk/CREDITS.TXT
libcxx/trunk/include/memory
libcxx/trunk/include/string
Modified: libcxx/trunk/CREDITS.TXT
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/CREDITS.TXT?rev=146329&r1=146328&r2=146329&view=diff
==============================================================================
--- libcxx/trunk/CREDITS.TXT (original)
+++ libcxx/trunk/CREDITS.TXT Sat Dec 10 14:28:56 2011
@@ -32,3 +32,10 @@
N: Arvid Picciani
E: aep at exys dot org
D: Minor patches and musl port.
+
+N: Craig Silverstein
+E: csilvers at google.com
+D: Implemented Cityhash as the string hash function on 64-bit machines
+
+N: Google Inc.
+D: Copyright owner and contributor of the CityHash algorithm
Modified: libcxx/trunk/include/memory
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/memory?rev=146329&r1=146328&r2=146329&view=diff
==============================================================================
--- libcxx/trunk/include/memory (original)
+++ libcxx/trunk/include/memory Sat Dec 10 14:28:56 2011
@@ -2719,18 +2719,22 @@
template <class _Tp> struct hash;
+// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
+// is 64 bits. This is because cityhash64 uses 64bit x 64bit
+// multiplication, which can be very slow on 32-bit systems.
template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
-struct __murmur2;
+struct __murmur2_or_cityhash;
template <class _Size>
-struct __murmur2<_Size, 32>
+struct __murmur2_or_cityhash<_Size, 32>
{
_Size operator()(const void* __key, _Size __len);
};
+// murmur2
template <class _Size>
_Size
-__murmur2<_Size, 32>::operator()(const void* __key, _Size __len)
+__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
{
const _Size __m = 0x5bd1e995;
const _Size __r = 24;
@@ -2762,50 +2766,166 @@
}
template <class _Size>
-struct __murmur2<_Size, 64>
+struct __murmur2_or_cityhash<_Size, 64>
{
_Size operator()(const void* __key, _Size __len);
+
+ private:
+ // Some primes between 2^63 and 2^64.
+ static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
+ static const _Size __k1 = 0xb492b66fbe98f273ULL;
+ static const _Size __k2 = 0x9ae16a3b2f90404fULL;
+ static const _Size __k3 = 0xc949d7c7509e6557ULL;
+
+ static _Size __rotate(_Size __val, int __shift) {
+ return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
+ }
+
+ static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
+ return (__val >> __shift) | (__val << (64 - __shift));
+ }
+
+ static _Size __shift_mix(_Size __val) {
+ return __val ^ (__val >> 47);
+ }
+
+ static _Size __hash_len_16(_Size __u, _Size __v) {
+ const _Size __mul = 0x9ddfea08eb382d69ULL;
+ _Size __a = (__u ^ __v) * __mul;
+ __a ^= (__a >> 47);
+ _Size __b = (__v ^ __a) * __mul;
+ __b ^= (__b >> 47);
+ __b *= __mul;
+ return __b;
+ }
+
+ static _Size __hash_len_0_to_16(const char* __s, _Size __len) {
+ if (__len > 8) {
+ const _Size __a = *(const _Size*)__s;
+ const _Size __b = *(const _Size*)(__s + __len - 8);
+ return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
+ }
+ if (__len >= 4) {
+ const uint32_t __a = *(const uint32_t*)(__s);
+ const uint32_t __b = *(const uint32_t*)(__s + __len - 4);
+ return __hash_len_16(__len + (__a << 3), __b);
+ }
+ if (__len > 0) {
+ const unsigned char __a = __s[0];
+ const unsigned char __b = __s[__len >> 1];
+ const unsigned char __c = __s[__len - 1];
+ const uint32_t __y = static_cast<uint32_t>(__a) +
+ (static_cast<uint32_t>(__b) << 8);
+ const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
+ return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
+ }
+ return __k2;
+ }
+
+ static _Size __hash_len_17_to_32(const char *__s, _Size __len) {
+ const _Size __a = *(const _Size*)(__s) * __k1;
+ const _Size __b = *(const _Size*)(__s + 8);
+ const _Size __c = *(const _Size*)(__s + __len - 8) * __k2;
+ const _Size __d = *(const _Size*)(__s + __len - 16) * __k0;
+ return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
+ __a + __rotate(__b ^ __k3, 20) - __c + __len);
+ }
+
+ // Return a 16-byte hash for 48 bytes. Quick and dirty.
+ // Callers do best to use "random-looking" values for a and b.
+ static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
+ _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b) {
+ __a += __w;
+ __b = __rotate(__b + __a + __z, 21);
+ const _Size __c = __a;
+ __a += __x;
+ __a += __y;
+ __b += __rotate(__a, 44);
+ return pair<_Size, _Size>(__a + __z, __b + __c);
+ }
+
+ // Return a 16-byte hash for s[0] ... s[31], a, and b. Quick and dirty.
+ static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
+ const char* __s, _Size __a, _Size __b) {
+ return __weak_hash_len_32_with_seeds(*(const _Size*)(__s),
+ *(const _Size*)(__s + 8),
+ *(const _Size*)(__s + 16),
+ *(const _Size*)(__s + 24),
+ __a,
+ __b);
+ }
+
+ // Return an 8-byte hash for 33 to 64 bytes.
+ static _Size __hash_len_33_to_64(const char *__s, size_t __len) {
+ _Size __z = *(const _Size*)(__s + 24);
+ _Size __a = *(const _Size*)(__s) +
+ (__len + *(const _Size*)(__s + __len - 16)) * __k0;
+ _Size __b = __rotate(__a + __z, 52);
+ _Size __c = __rotate(__a, 37);
+ __a += *(const _Size*)(__s + 8);
+ __c += __rotate(__a, 7);
+ __a += *(const _Size*)(__s + 16);
+ _Size __vf = __a + __z;
+ _Size __vs = __b + __rotate(__a, 31) + __c;
+ __a = *(const _Size*)(__s + 16) + *(const _Size*)(__s + __len - 32);
+ __z += *(const _Size*)(__s + __len - 8);
+ __b = __rotate(__a + __z, 52);
+ __c = __rotate(__a, 37);
+ __a += *(const _Size*)(__s + __len - 24);
+ __c += __rotate(__a, 7);
+ __a += *(const _Size*)(__s + __len - 16);
+ _Size __wf = __a + __z;
+ _Size __ws = __b + __rotate(__a, 31) + __c;
+ _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
+ return __shift_mix(__r * __k0 + __vs) * __k2;
+ }
};
+// cityhash64
template <class _Size>
_Size
-__murmur2<_Size, 64>::operator()(const void* __key, _Size __len)
+__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
{
- const _Size __m = 0xc6a4a7935bd1e995ull;
- const _Size __r = 47;
- _Size __h = __len * __m;
- const unsigned char* __data = static_cast<const unsigned char*>(__key);
- for (; __len >= 8; __data += 8, __len -= 8)
- {
- _Size __k = *(const _Size*)__data;
- __k *= __m;
- __k ^= __k >> __r;
- __k *= __m;
- __h ^= __k;
- __h *= __m;
+ const char* __s = static_cast<const char*>(__key);
+ if (__len <= 32) {
+ if (__len <= 16) {
+ return __hash_len_0_to_16(__s, __len);
+ } else {
+ return __hash_len_17_to_32(__s, __len);
}
- switch (__len)
- {
- case 7:
- __h ^= __data[6] << 48;
- case 6:
- __h ^= __data[5] << 40;
- case 5:
- __h ^= __data[4] << 32;
- case 4:
- __h ^= __data[3] << 24;
- case 3:
- __h ^= __data[2] << 16;
- case 2:
- __h ^= __data[1] << 8;
- case 1:
- __h ^= __data[0];
- __h *= __m;
- }
- __h ^= __h >> __r;
- __h *= __m;
- __h ^= __h >> __r;
- return __h;
+ } else if (__len <= 64) {
+ return __hash_len_33_to_64(__s, __len);
+ }
+
+ // For strings over 64 bytes we hash the end first, and then as we
+ // loop we keep 56 bytes of state: v, w, x, y, and z.
+ _Size __x = *(const _Size*)(__s + __len - 40);
+ _Size __y = *(const _Size*)(__s + __len - 16) +
+ *(const _Size*)(__s + __len - 56);
+ _Size __z = __hash_len_16(*(const _Size*)(__s + __len - 48) + __len,
+ *(const _Size*)(__s + __len - 24));
+ pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
+ pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
+ __x = __x * __k1 + *(const _Size*)(__s);
+
+ // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
+ __len = (__len - 1) & ~static_cast<_Size>(63);
+ do {
+ __x = __rotate(__x + __y + __v.first + *(const _Size*)(__s + 8), 37) * __k1;
+ __y = __rotate(__y + __v.second + *(const _Size*)(__s + 48), 42) * __k1;
+ __x ^= __w.second;
+ __y += __v.first + *(const _Size*)(__s + 40);
+ __z = __rotate(__z + __w.first, 33) * __k1;
+ __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
+ __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
+ __y + *(const _Size*)(__s + 16));
+ std::swap(__z, __x);
+ __s += 64;
+ __len -= 64;
+ } while (__len != 0);
+ return __hash_len_16(
+ __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
+ __hash_len_16(__v.second, __w.second) + __x);
}
template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
@@ -2863,7 +2983,7 @@
};
} __u;
__u.__t = __v;
- return __murmur2<size_t>()(&__u, sizeof(__u));
+ return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
}
};
@@ -2885,7 +3005,7 @@
};
} __u;
__u.__t = __v;
- return __murmur2<size_t>()(&__u, sizeof(__u));
+ return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
}
};
@@ -2908,7 +3028,7 @@
};
} __u;
__u.__t = __v;
- return __murmur2<size_t>()(&__u, sizeof(__u));
+ return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
}
};
Modified: libcxx/trunk/include/string
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/string?rev=146329&r1=146328&r2=146329&view=diff
==============================================================================
--- libcxx/trunk/include/string (original)
+++ libcxx/trunk/include/string Sat Dec 10 14:28:56 2011
@@ -3916,7 +3916,7 @@
size_t _LIBCPP_INLINE_VISIBILITY __do_string_hash(_Ptr __p, _Ptr __e)
{
typedef typename iterator_traits<_Ptr>::value_type value_type;
- return __murmur2<size_t>()(__p, (__e-__p)*sizeof(value_type));
+ return __murmur2_or_cityhash<size_t>()(__p, (__e-__p)*sizeof(value_type));
}
template<class _CharT, class _Traits, class _Allocator>
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