fc64a7bef4
Some user opcode handler actually gets called when JIT is used, so do not disable JIT even if these user opcode handlers were registered, just ignore them. ZEND_EXIT can help Swoole to detect exit/die operation and exit from the current coroutine and record exit_status correctly. ZEND_*_SILENCE can help Swoole to switch EG(error_reporting) to keep the right behavior when using the error control operator. So we ignore ZEND_EXIT, ZEND_BEGIN_SILENCE, ZEND_END_SILENCE in JIT check here. Closes GH-6640.
Opcache JIT
This is the implementation of Opcache's JIT (Just-In-Time compiler), This converts the PHP Virtual Machine's opcodes into x64/x86 assembly, on POSIX platforms and Windows.
It generates native code directly from PHP byte-code and information collected by the SSA static analysis framework (a part of the opcache optimizer). Code is usually generated separately for each PHP byte-code instruction. Only a few combinations are considered together (e.g. compare + conditional jump).
See the JIT RFC for more details.
DynAsm
This uses DynAsm (developed for LuaJIT project) for the generation of native code. It's a very lightweight and advanced tool, but does assume good, and very low-level development knowledge of target assembler languages. In the past we tried LLVM, but its code generation speed was almost 100 times slower, making it prohibitively expensive to use.
The unofficial DynASM Documentation has a tutorial, reference, and instruction listing.
zend_jit_x86.dasc gets automatically converted to zend_jit_x86.c by the bundled
dynasm during make.