From: Nikita Popov <nikic@php.net>
Date: Tue, 17 May 2016 20:17:22 +0000 (+0200)
Subject: Move builtin_ctzl portability into zend_bitset.h
X-Git-Tag: php-7.1.0alpha1~107
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=14023d39c1ae2fc48bb9ab2c87ea7136c58c2401;p=php

Move builtin_ctzl portability into zend_bitset.h

Use this function in both zend_mm_bitset_find_one and
zend_bitset_first.

Maybe zend_bitset.h is not quite the right place for it, but I did
not want to include this in a globally included header like
zend_long.h or zend_portability.h.
---

diff --git a/Zend/zend_alloc.c b/Zend/zend_alloc.c
index e7a8e0d2a5..a7e3808e7c 100644
--- a/Zend/zend_alloc.c
+++ b/Zend/zend_alloc.c
@@ -58,6 +58,7 @@
 #include "zend_globals.h"
 #include "zend_operators.h"
 #include "zend_multiply.h"
+#include "zend_bitset.h"
 
 #ifdef HAVE_SIGNAL_H
 # include <signal.h>
@@ -546,45 +547,6 @@ static zend_always_inline int zend_mm_bitset_nts(zend_mm_bitset bitset)
 #endif
 }
 
-/* number of trailing zero bits (0x01 -> 1; 0x40 -> 6; 0x00 -> LEN) */
-static zend_always_inline int zend_mm_bitset_ntz(zend_mm_bitset bitset)
-{
-#if (defined(__GNUC__) || __has_builtin(__builtin_ctzl)) && SIZEOF_ZEND_LONG == SIZEOF_LONG && defined(PHP_HAVE_BUILTIN_CTZL)
-	return __builtin_ctzl(bitset);
-#elif (defined(__GNUC__) || __has_builtin(__builtin_ctzll)) && defined(PHP_HAVE_BUILTIN_CTZLL)
-	return __builtin_ctzll(bitset);
-#elif defined(_WIN32)
-	unsigned long index;
-
-#if defined(_WIN64)
-	if (!BitScanForward64(&index, bitset)) {
-#else
-	if (!BitScanForward(&index, bitset)) {
-#endif
-		/* undefined behavior */
-		return 32;
-	}
-
-	return (int)index;
-#else
-	int n;
-
-	if (bitset == (zend_mm_bitset)0) return ZEND_MM_BITSET_LEN;
-
-	n = 1;
-#if SIZEOF_ZEND_LONG == 8
-	if (sizeof(zend_mm_bitset) == 8) {
-		if ((bitset & 0xffffffff) == 0) {n += 32; bitset = bitset >> Z_UL(32);}
-	}
-#endif
-	if ((bitset & 0x0000ffff) == 0) {n += 16; bitset = bitset >> 16;}
-	if ((bitset & 0x000000ff) == 0) {n +=  8; bitset = bitset >>  8;}
-	if ((bitset & 0x0000000f) == 0) {n +=  4; bitset = bitset >>  4;}
-	if ((bitset & 0x00000003) == 0) {n +=  2; bitset = bitset >>  2;}
-	return n - (bitset & 1);
-#endif
-}
-
 static zend_always_inline int zend_mm_bitset_find_zero(zend_mm_bitset *bitset, int size)
 {
 	int i = 0;
@@ -606,7 +568,7 @@ static zend_always_inline int zend_mm_bitset_find_one(zend_mm_bitset *bitset, in
 	do {
 		zend_mm_bitset tmp = bitset[i];
 		if (tmp != 0) {
-			return i * ZEND_MM_BITSET_LEN + zend_mm_bitset_ntz(tmp);
+			return i * ZEND_MM_BITSET_LEN + zend_ulong_ntz(tmp);
 		}
 		i++;
 	} while (i < size);
@@ -941,7 +903,7 @@ static void *zend_mm_alloc_pages(zend_mm_heap *heap, int pages_count ZEND_FILE_L
 					tmp = *(bitset++);
 				}
 				/* find first 1 bit */
-				len = (i + zend_mm_bitset_ntz(tmp)) - page_num;
+				len = (i + zend_ulong_ntz(tmp)) - page_num;
 				if (len >= pages_count) {
 					goto found;
 				}
@@ -998,7 +960,7 @@ static void *zend_mm_alloc_pages(zend_mm_heap *heap, int pages_count ZEND_FILE_L
 					tmp = *(bitset++);
 				}
 				/* find first 1 bit */
-				len = i + zend_mm_bitset_ntz(tmp) - page_num;
+				len = i + zend_ulong_ntz(tmp) - page_num;
 				if (len >= pages_count) {
 					if (len == pages_count) {
 						goto found;
diff --git a/Zend/zend_bitset.h b/Zend/zend_bitset.h
index e1a95466b8..1b42201a7a 100644
--- a/Zend/zend_bitset.h
+++ b/Zend/zend_bitset.h
@@ -36,6 +36,47 @@ typedef zend_ulong *zend_bitset;
 # define ZEND_BITSET_BIT_NUM(n)		((n) % (sizeof(zend_long) * 8))
 #endif
 
+#define ZEND_BITSET_ALLOCA(n, use_heap) \
+	(zend_bitset)do_alloca((n) * ZEND_BITSET_ELM_SIZE, use_heap)
+
+/* Number of trailing zero bits (0x01 -> 0; 0x40 -> 6; 0x00 -> LEN) */
+static zend_always_inline int zend_ulong_ntz(zend_ulong num)
+{
+#if (defined(__GNUC__) || __has_builtin(__builtin_ctzl)) \
+	&& SIZEOF_ZEND_LONG == SIZEOF_LONG && defined(PHP_HAVE_BUILTIN_CTZL)
+	return __builtin_ctzl(num);
+#elif (defined(__GNUC__) || __has_builtin(__builtin_ctzll)) && defined(PHP_HAVE_BUILTIN_CTZLL)
+	return __builtin_ctzll(num);
+#elif defined(_WIN32)
+	unsigned long index;
+
+#if defined(_WIN64)
+	if (!BitScanForward64(&index, num)) {
+#else
+	if (!BitScanForward(&index, num)) {
+#endif
+		/* undefined behavior */
+		return 32;
+	}
+
+	return (int) index;
+#else
+	int n;
+
+	if (num == Z_UL(0)) return ZEND_MM_BITSET_LEN;
+
+	n = 1;
+#if SIZEOF_ZEND_LONG == 8
+	if ((num & 0xffffffff) == 0) {n += 32; num = num >> Z_UL(32);}
+#endif
+	if ((num & 0x0000ffff) == 0) {n += 16; num = num >> 16;}
+	if ((num & 0x000000ff) == 0) {n +=  8; num = num >>  8;}
+	if ((num & 0x0000000f) == 0) {n +=  4; num = num >>  4;}
+	if ((num & 0x00000003) == 0) {n +=  2; num = num >>  2;}
+	return n - (num & 1);
+#endif
+}
+
 /* Returns the number of zend_ulong words needed to store a bitset that is N
    bits long.  */
 static inline uint32_t zend_bitset_len(uint32_t n)
@@ -43,9 +84,6 @@ static inline uint32_t zend_bitset_len(uint32_t n)
 	return (n + ((sizeof(zend_long) * 8) - 1)) / (sizeof(zend_long) * 8);
 }
 
-#define ZEND_BITSET_ALLOCA(n, use_heap) \
-	(zend_bitset)do_alloca((n) * ZEND_BITSET_ELM_SIZE, use_heap)
-
 static inline zend_bool zend_bitset_in(zend_bitset set, uint32_t n)
 {
 	return (set[ZEND_BITSET_ELM_NUM(n)] & (Z_UL(1) << ZEND_BITSET_BIT_NUM(n))) != Z_UL(0);
@@ -155,13 +193,7 @@ static inline int zend_bitset_first(zend_bitset set, uint32_t len)
 
 	for (i = 0; i < len; i++) {
 		if (set[i]) {
-			int j = ZEND_BITSET_ELM_SIZE * 8 * i;
-			zend_ulong x = set[i];
-			while ((x & Z_UL(1)) == 0) {
-				x = x >> Z_UL(1);
-				j++;
-			}
-			return j;
+			return ZEND_BITSET_ELM_SIZE * 8 * i + zend_ulong_ntz(set[i]);
 		}
 	}
 	return -1; /* empty set */