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tree: use alignof/alignas as it is always available #25017

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dfabb8c
tree: alignof is always available
Girgias Oct 28, 2026
a333176
use alignas instead of ZEND_SET_ALIGNED() when possible
Girgias Oct 29, 2026
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7 changes: 2 additions & 5 deletions Zend/Zend.m4
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Original file line number Diff line number Diff line change
Expand Up @@ -382,18 +382,15 @@ AC_DEFUN([ZEND_CHECK_ALIGNMENT],
[AC_RUN_IFELSE([AC_LANG_SOURCE([
#include <stdio.h>
#include <stdlib.h>
#include <stdalign.h>

typedef union _mm_align_test {
void *ptr;
double dbl;
long lng;
} mm_align_test;

#if (defined (__GNUC__) && __GNUC__ >= 2)
#define ZEND_MM_ALIGNMENT (__alignof__ (mm_align_test))
#else
#define ZEND_MM_ALIGNMENT (sizeof(mm_align_test))
#endif
#define ZEND_MM_ALIGNMENT (alignof(mm_align_test))

int main(void)
{
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2 changes: 1 addition & 1 deletion Zend/zend_string.c
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Expand Up @@ -53,7 +53,7 @@ ZEND_API zend_string *zend_one_char_string[256];
ZEND_API zend_string **zend_known_strings = NULL;

/* this is read-only, so it's ok */
ZEND_SET_ALIGNED(16, static const char zend_hexconvtab[]) = "0123456789abcdef";
alignas(16) static const char zend_hexconvtab[] = "0123456789abcdef";

static zend_always_inline void zend_bin2hex_impl(char *out, const unsigned char *in, size_t in_len, const char *hexconvtab)
{
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13 changes: 0 additions & 13 deletions configure.ac
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Expand Up @@ -493,19 +493,6 @@ PHP_CHECK_AVX512_SUPPORTS
dnl Check AVX512 VBMI
PHP_CHECK_AVX512_VBMI_SUPPORTS

dnl Check for __alignof__ support in the compiler
AC_CACHE_CHECK([whether the compiler supports __alignof__],
[php_cv_have_alignof],
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [
int align = __alignof__(int);
(void)align;
])],
[php_cv_have_alignof=yes],
[php_cv_have_alignof=no])])
AS_VAR_IF([php_cv_have_alignof], [yes],
[AC_DEFINE([HAVE_ALIGNOF], [1],
[Define to 1 if the compiler supports '__alignof__'.])])

dnl Check for structure members.
AC_CHECK_MEMBERS([struct tm.tm_gmtoff],,,[#include <time.h>])
AC_CHECK_MEMBERS(m4_normalize([
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18 changes: 5 additions & 13 deletions ext/hash/hash.c
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Expand Up @@ -26,18 +26,10 @@
#include "zend_exceptions.h"
#include "zend_interfaces.h"
#include "zend_smart_str.h"
#include <stdalign.h>

@TimWolla TimWolla Oct 29, 2026

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Should we include this in zend_portability.h instead?

@Girgias Girgias Oct 29, 2026

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It already is included in zend_portability


#include "hash_arginfo.h"

#ifdef PHP_WIN32
# define __alignof__ __alignof
#else
# ifndef HAVE_ALIGNOF
# include <stddef.h>
# define __alignof__(type) offsetof (struct { char c; type member;}, member)
# endif
#endif

static HashTable php_hash_hashtable;
zend_class_entry *php_hashcontext_ce;
static zend_object_handlers php_hashcontext_handlers;
Expand Down Expand Up @@ -138,16 +130,16 @@ static size_t parse_serialize_spec(
/* parse size */
if (*spec == 's' || *spec == 'S') {
*sz = 2;
alignment = __alignof__(uint16_t); /* usually 2 */
alignment = alignof(uint16_t); /* usually 2 */
} else if (*spec == 'l' || *spec == 'L') {
*sz = 4;
alignment = __alignof__(uint32_t); /* usually 4 */
alignment = alignof(uint32_t); /* usually 4 */
} else if (*spec == 'q' || *spec == 'Q') {
*sz = 8;
alignment = __alignof__(uint64_t); /* usually 8 */
alignment = alignof(uint64_t); /* usually 8 */
} else if (*spec == 'i' || *spec == 'I') {
*sz = sizeof(int);
alignment = __alignof__(int); /* usually 4 */
alignment = alignof(int); /* usually 4 */
} else {
ZEND_ASSERT(*spec == 'b' || *spec == 'B');
*sz = 1;
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2 changes: 1 addition & 1 deletion ext/opcache/ZendAccelerator.h
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Expand Up @@ -292,7 +292,7 @@ typedef struct _zend_accel_shared_globals {
const void **jit_exit_groups;

/* Interned Strings Support (must be the last element) */
ZEND_SET_ALIGNED(ZEND_STRING_TABLE_POS_ALIGNMENT, zend_string_table interned_strings);
alignas(ZEND_STRING_TABLE_POS_ALIGNMENT) zend_string_table interned_strings;
} zend_accel_shared_globals;

#ifdef ZEND_WIN32
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2 changes: 1 addition & 1 deletion ext/random/random.c
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Expand Up @@ -316,7 +316,7 @@ PHPAPI void *php_random_default_status(void)
/* }}} */

/* this is read-only, so it's ok */
ZEND_SET_ALIGNED(16, static const char hexconvtab[]) = "0123456789abcdef";
alignas(16) static const char hexconvtab[] = "0123456789abcdef";

/* {{{ php_random_bin2hex_le */
/* stolen from standard/string.c */
Expand Down
40 changes: 10 additions & 30 deletions ext/standard/crypt_sha256.c
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Expand Up @@ -8,17 +8,9 @@
#include <errno.h>
#include <limits.h>

#ifdef PHP_WIN32
# define __alignof__ __alignof
#else
# ifndef HAVE_ALIGNOF
# include <stddef.h>
# define __alignof__(type) offsetof (struct { char c; type member;}, member)
# endif
#endif

#include <stdio.h>
#include <stdlib.h>
#include <stdalign.h>

#ifdef PHP_WIN32
# include <string.h>
Expand Down Expand Up @@ -260,14 +252,7 @@ static void sha256_process_bytes(const void *buffer, size_t len, struct sha256_c

/* Process available complete blocks. */
if (len >= 64) {
/* To check alignment gcc has an appropriate operator. Other
compilers don't. */
#if __GNUC__ >= 2
# define UNALIGNED_P(p) (((uintptr_t) p) % __alignof__ (uint32_t) != 0)
#else
# define UNALIGNED_P(p) (((uintptr_t) p) % sizeof (uint32_t) != 0)
#endif
if (UNALIGNED_P (buffer))
if ((uintptr_t)buffer % alignof(uint32_t) != 0)
while (len > 64) {
sha256_process_block(memcpy(ctx->buffer, buffer, 64), 64, ctx);
buffer = (const char *) buffer + 64;
Expand Down Expand Up @@ -317,13 +302,8 @@ static const char b64t[64] ZEND_NONSTRING =

char * php_sha256_crypt_r(const char *key, const char *salt, char *buffer, int buflen)
{
#ifdef PHP_WIN32
ZEND_SET_ALIGNED(32, unsigned char alt_result[32]);
ZEND_SET_ALIGNED(32, unsigned char temp_result[32]);
#else
ZEND_SET_ALIGNED(__alignof__ (uint32_t), unsigned char alt_result[32]);
ZEND_SET_ALIGNED(__alignof__ (uint32_t), unsigned char temp_result[32]);
#endif
alignas(uint32_t) unsigned char alt_result[32];
alignas(uint32_t) unsigned char temp_result[32];

struct sha256_ctx ctx;
struct sha256_ctx alt_ctx;
Expand Down Expand Up @@ -371,15 +351,15 @@ char * php_sha256_crypt_r(const char *key, const char *salt, char *buffer, int b
SET_ALLOCA_FLAG(use_heap_key);
SET_ALLOCA_FLAG(use_heap_salt);

if ((uintptr_t)key % __alignof__ (uint32_t) != 0) {
tmp_key = (char *) do_alloca(key_len + __alignof__(uint32_t), use_heap_key);
key = copied_key = memcpy(tmp_key + __alignof__(uint32_t) - (uintptr_t)tmp_key % __alignof__(uint32_t), key, key_len);
if ((uintptr_t)key % alignof(uint32_t) != 0) {
tmp_key = (char *) do_alloca(key_len + alignof(uint32_t), use_heap_key);
key = copied_key = memcpy(tmp_key + alignof(uint32_t) - (uintptr_t)tmp_key % alignof(uint32_t), key, key_len);
}

if ((uintptr_t)salt % __alignof__(uint32_t) != 0) {
tmp_salt = (char *) do_alloca(salt_len + 1 + __alignof__(uint32_t), use_heap_salt);
if ((uintptr_t)salt % alignof(uint32_t) != 0) {
tmp_salt = (char *) do_alloca(salt_len + 1 + alignof(uint32_t), use_heap_salt);
salt = copied_salt =
memcpy(tmp_salt + __alignof__(uint32_t) - (uintptr_t)tmp_salt % __alignof__ (uint32_t), salt, salt_len);
memcpy(tmp_salt + alignof(uint32_t) - (uintptr_t)tmp_salt % alignof(uint32_t), salt, salt_len);
copied_salt[salt_len] = 0;
}

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39 changes: 10 additions & 29 deletions ext/standard/crypt_sha512.c
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Expand Up @@ -7,17 +7,10 @@

#include <errno.h>
#include <limits.h>
#ifdef PHP_WIN32
# define __alignof__ __alignof
#else
# ifndef HAVE_ALIGNOF
# include <stddef.h>
# define __alignof__(type) offsetof (struct { char c; type member;}, member)
# endif
#endif

#include <stdio.h>
#include <stdlib.h>
#include <stdalign.h>

#ifdef PHP_WIN32
# include <string.h>
Expand Down Expand Up @@ -294,14 +287,7 @@ sha512_process_bytes(const void *buffer, size_t len, struct sha512_ctx *ctx) {
/* Process available complete blocks. */
if (len >= 128) {
#ifndef _STRING_ARCH_unaligned
/* To check alignment gcc has an appropriate operator. Other
compilers don't. */
# if __GNUC__ >= 2
# define UNALIGNED_P(p) (((uintptr_t) p) % __alignof__ (uint64_t) != 0)
# else
# define UNALIGNED_P(p) (((uintptr_t) p) % sizeof(uint64_t) != 0)
# endif
if (UNALIGNED_P(buffer))
if ((uintptr_t)buffer % alignof(uint64_t) != 0)
while (len > 128) {
sha512_process_block(memcpy(ctx->buffer, buffer, 128), 128, ctx);
buffer = (const char *) buffer + 128;
Expand Down Expand Up @@ -355,13 +341,8 @@ static const char b64t[64] ZEND_NONSTRING =

char *
php_sha512_crypt_r(const char *key, const char *salt, char *buffer, int buflen) {
#ifdef PHP_WIN32
ZEND_SET_ALIGNED(64, unsigned char alt_result[64]);
ZEND_SET_ALIGNED(64, unsigned char temp_result[64]);
#else
ZEND_SET_ALIGNED(__alignof__ (uint64_t), unsigned char alt_result[64]);
ZEND_SET_ALIGNED(__alignof__ (uint64_t), unsigned char temp_result[64]);
#endif
alignas(uint64_t) unsigned char alt_result[64];
alignas(uint64_t) unsigned char temp_result[64];
struct sha512_ctx ctx;
struct sha512_ctx alt_ctx;
size_t salt_len;
Expand Down Expand Up @@ -409,15 +390,15 @@ php_sha512_crypt_r(const char *key, const char *salt, char *buffer, int buflen)
SET_ALLOCA_FLAG(use_heap_key);
SET_ALLOCA_FLAG(use_heap_salt);

if ((uintptr_t)key % __alignof__ (uint64_t) != 0) {
tmp_key = (char *) do_alloca(key_len + __alignof__ (uint64_t), use_heap_key);
if ((uintptr_t)key % alignof(uint64_t) != 0) {
tmp_key = (char *) do_alloca(key_len + alignof(uint64_t), use_heap_key);
key = copied_key =
memcpy(tmp_key + __alignof__(uint64_t) - (uintptr_t)tmp_key % __alignof__(uint64_t), key, key_len);
memcpy(tmp_key + alignof(uint64_t) - (uintptr_t)tmp_key % alignof(uint64_t), key, key_len);
}

if ((uintptr_t)salt % __alignof__ (uint64_t) != 0) {
tmp_salt = (char *) do_alloca(salt_len + 1 + __alignof__(uint64_t), use_heap_salt);
salt = copied_salt = memcpy(tmp_salt + __alignof__(uint64_t) - (uintptr_t)tmp_salt % __alignof__(uint64_t), salt, salt_len);
if ((uintptr_t)salt % alignof(uint64_t) != 0) {
tmp_salt = (char *) do_alloca(salt_len + 1 + alignof(uint64_t), use_heap_salt);
salt = copied_salt = memcpy(tmp_salt + alignof(uint64_t) - (uintptr_t)tmp_salt % alignof(uint64_t), salt, salt_len);
copied_salt[salt_len] = 0;
}

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2 changes: 1 addition & 1 deletion ext/standard/string.c
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Expand Up @@ -4076,7 +4076,7 @@ PHPAPI zend_string *php_addslashes(zend_string *str) /* {{{ */
zend_string *php_addslashes_sse42(zend_string *str)
# endif
{
ZEND_SET_ALIGNED(16, static const char slashchars[16]) = "\'\"\\\0";
alignas(16) static const char slashchars[16] = "\'\"\\\0";
__m128i w128, s128;
uint32_t res = 0;
/* maximum string length, worst case situation */
Expand Down
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