In PHP-5.6 and below each argument passed to user function was copies on VM stack twice.
Now we always have ZEND_INIT_FCALL (or simular) opcode that pushes "call frame" on top of VM stack.
"Call frame" is actually the same zend_execute_data structure.
All the following ZEND_SEND instructions push arguments on top of the stack in a way that they directly comes into corresponding CV variables of the called frame. Extra arguments are copied at the end of stack frame (after all CV and TMP variables) on function enterance.
There are two minor incompatibilities:
1) It's not allowed to decalre functions redefining arguments e.g. "function foo($a,$a) {}".
2) func_get_arg() and func_get args() return the current value of argument and not the original value that was sent.
It should be accessed using Z_CACHE_SLOT() macro.
zend_literal structure is removed.
API functions that accepted pointer to zend_literal now accept pointer to zval or cache_slot directly.
Calls of such functiond that now accept cache_slot need to be changed to pass -1 instead of NULL.
This commit disallows the use of trailing positional arguments
after argument unpacking was used. The following calls are no
longer valid:
fn(...$array, $var);
fn(...$array1, $var, ...$array2);
However, all of the following continue to be valid:
fn($var, ...$array);
fn(...$array1, ...$array2);
fn($var, ...$array1, ...$array2);
The reason behind this change is a stack allocation issue pointed
out by Dmitry: As of PHP 5.5 the stack necessary for pushing
arguments is precomputed and preallocated, as such the individual
SEND opcodes no longer verify that there is enough stack space.
The unpacked arguments will occupy some of that preallocated
space and as such following positional arguments could write past
a stack page boundary.
An alternative resolution for this issue is to ensure that there
is enough space for the remaining arguments in the UNPACK opcode.
However making this allocation precise (rather than using a
conversative over-estimate) would require some effort. Given that
this particular aspect of the feature wasn't very popular in the
first place, it doesn't seem worth the effort.
Instead of storing the argument number in the znode of the parameter
list, store it in fcall->arg_num. This mainly cleans up the parameter
parsing code, which previously had to duplicate all rules (this
becomes more excessive as more features are added, e.g. named params
would already require a minimum of 14 rules...)
Instead of directly pushing the zend_function* onto the
function_call_stack, push this structure. This allows us to store
additional data on this stack.
* upstream/PHP-5.6: (399 commits)
Fixed issue #115 (path issue when using phar). Fixed issue #149 (Phar mount points not working with OPcache enabled).
Added tests for PHAR/OPCahce incompatibilities
Update NEWS
Fixed bug #65947 (basename is no more working after fgetcsv in certain situation)
Update NEWS
Fixed Bug #66043 (Segfault calling bind_param() on mysqli)
NEWS entry
NEWS entry
Fix bug #65946 - pdo_sql_parser.c permanently converts values bound to strings
bump API versions
Add a couple more test cases to parse_url() tests
fix missing change from 'tcp_socket' to the more common 'server'
fix many parallel test issues
Cleanup temp test file
Revert "Fixed issue #115 (path issue when using phar)."
Update LiteSpeed SAPI code to V6.4
Fixed typo in Makefile.frag
updated NEWS
Remove outdate codes, make it clearer, although just a bit..
Update NEWS
...
Conflicts:
Zend/zend_compile.h