When executing a foreach ($ht as &$ref), foreach calls zend_hash_iterator_pos_ex() on every iteration. If the HashTable contained in the $ht variable is not the tracked HashTable, it will reset the position to the internal array pointer of the array currently in $ht.
This behaviour is generally fine, but undesirable for copy-on-write copies of the iterated HashTable. This may trivially occur when the iterated over HashTable is assigned to some variable, then the iterated over variable modified, leading to array separation, changing the HashTable pointer in the variable. Thus foreach happily restarting iteration.
This behaviour (despite existing since PHP 7.0) is considered a bug, if not only for the behaviour being unexpected to the user, also copy-on-write should not have trivially observable side-effects by mere assignment.
The bugfix consists of duplicating HashTableIterators whenever zend_array_dup() is called (the primitive used on array separation).
When a further access to the HashPosition through the HashTableIterators API happens and the HashTable does not match the tracked one, all the duplicates (which are tracked by single linked list) are searched for the wanted HashTable. If found, the HashTableIterator is replaced by the found copy and all other copies are removed.
This ensures that we always end up tracking the correct HashTable.
Fixes GH-11244.
Signed-off-by: Bob Weinand <bobwei9@hotmail.com>
In older versions of GCC (<=4.5) designated initializers would not accept member
names nested inside anonymous structures. Instead, we need to use a positional
member wrapped in {}.
Fixes GH-11063
Closes GH-11212
There are more places in zend_hash.c where the resize happened after some values on the HashTable struct were set.
I reordered them all, but writing a test for these would rely on the particular amount of bytes allocated at given points in time.
We prefer to use AVX2 instructions for code efficiency improvement
1) Reduce instruction path length
Generic x86 Instr: 16, SSE2: 6, AVX2: 4
2) Better ICache locality and density
To enable AVX2 instructions, compile with '-mavx2' option via CFLAGS
environment variable or command line argument.
Note: '-mavx' option still leads to using SSE2 instructions.
_mm256_cmpeq_epi64() requires AVX2 (-mavx2).
Testing:
Build with and without '-mavx2', 'make TEST_PHP_ARGS=-j8 test'
presented the same test report.
Signed-off-by: Tony Su <tao.su@intel.com>
zend_hash allocates a hash table twice as big as nTableSize
(HT_HASH_SIZE(HT_SIZE_TO_MASK(nTableSize)) == nTableSize*2), so HT_MAX_SIZE
must be half the max table size or less.
Fixes GH-10240
Shift header include
In the C file, include the header first so missing #includes are
detected by the compiler, and use lighter header dependencies in the
header, to speed up compile times.
After discussing with someone, our current running theory is that the local
variable forces the compiler to reserve an additional register for the whole
lifespan of the function. Dropping it and just loading the value should restore
the previous code generation.
Closes GH-9876
* Port zend_cpuid for windows arm64
* Fix zend_atomic windows arm64 build
* Fix windows arm64 multiply
* Enable arm64 neon for windows in standard extension
* Enable arm64 neon for windows in zend_hash.c
* Workaround for msvc arm64 optimization bug
Closes GH-9115.
This doesn't have an effect really, but humans and IDEs can struggle to see through the macro soup when they first interact with PHP's source code.
Moreover, this reduces some of the macro expansion hell when they appear in compiler warnings.
* ext/oci8: use zend_string_equals()
Eliminate duplicate code.
* main/php_variables: use zend_string_equals_literal()
Eliminate duplicate code.
* Zend/zend_string: add zend_string_equals_cstr()
Allows eliminating duplicate code.
* Zend, ext/{opcache,standard}, main/output: use zend_string_equals_cstr()
Eliminate duplicate code.
* Zend/zend_string: add zend_string_starts_with()
* ext/{opcache,phar,spl,standard}: use zend_string_starts_with()
This adds missing length checks to several callers, e.g. in
cache_script_in_shared_memory(). This is important when the
zend_string is shorter than the string parameter, when memcmp()
happens to check backwards; this can result in an out-of-bounds memory
access.
- for packed arrays we store just an array of zvals without keys.
- the elements of packed array are accessible throuf as ht->arPacked[i]
instead of ht->arData[i]
- in addition to general ZEND_HASH_FOREACH_* macros, we introduced similar
familied for packed (ZEND_HASH_PACKED_FORECH_*) and real hashes
(ZEND_HASH_MAP_FOREACH_*)
- introduced an additional family of macros to access elements of array
(packed or real hashes) ZEND_ARRAY_ELEMET_SIZE, ZEND_ARRAY_ELEMET_EX,
ZEND_ARRAY_ELEMET, ZEND_ARRAY_NEXT_ELEMENT, ZEND_ARRAY_PREV_ELEMENT
- zend_hash_minmax() prototype was changed to compare only values
Because of smaller data set, this patch may show performance improvement
on some apps and benchmarks that use packed arrays. (~1% on PHP-Parser)
TODO:
- sapi/phpdbg needs special support for packed arrays (WATCH_ON_BUCKET).
- zend_hash_sort_ex() may require converting packed arrays to hash.
Convert zend_hash_find_ex(..., 1) to zend_hash_find_known_hash(...)
Convert zend_hash_find_ex(..., 0) to zend_hash_find(...)
Also add serializable changes to UPGRADING.INTERNALS summary
This PR corrects misspellings identified by the check-spelling action.
The misspellings have been reported at jsoref@b6ba3e2#commitcomment-48946465
The action reports that the changes in this PR would make it happy: jsoref@602417c
Closes GH-6822.
