the main idea - the smaller the zend_op structure, the lees memory traffic is required to load VM instructions during execution. The patch reduces the size of each opcode from 48 to 32 bytes (saves 16 bytes for each opcode, and applications use thousands of opoceds). This reduced the number of CPU cache misses by 12% and improved performance of real-life apps by 1-2%.
The patch affects how constants and jump targets are represented in VM during execution. Previously they were implemented as absolute 64-bit pointers. Now they are relative 32-bit offsets.
In run-time constant now should be accessed as:
RT_CONSTANT(op_array, opine->op1) instead of opline->op1.zv
EX_CONSTANT(opline->op1) instead of opline->op1.zv
Jump targets:
OP_JMP_ADDR(opline, opline->op2) instead of opline->op2.jmp_addr
The patch doesn't change zend_op representation for 32-bit systems. They still use absolute addresses. The compile-time representation is also kept the same.
As far as I can discern these are leftovers of the interactive
shell implementation that was used before PHP 5.4. Now the readline
ext makes use of normal eval calls for this.
So, dropping these until there is evidence to the contrary, as they
currently wouldn't work anyway.
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.
* master:
Fixed issue #183 (TMP_VAR is not only used once)
Fix broken Junit output with --disable-cgi
Added folder mark
Further test fixes for the fdb2709 breakage.
Fix broken test caused by fdb2709.
Added tests for ZipArchive::addGlob() and ZipArchive::addPattern()
Fix run-tests.php with Valgrind >= 3.10.0.
Add microseconds to the serialised form of DateTime objects.
Improved test for bug #62479
fix typo in ODBC code
gcov: tentative fix for broken coverage data after fix for opcache coverage slightly hackish, but works. The idea is that we want to give priority to .gcda files in .libs dirs vs the files in the upper level dir
5.5.14 now
Fix bug #67060: use default mode of 660
Conflicts:
ext/date/php_date.c
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.
