php-in-php: delete StringZlib::preloadLibz dlopen — ZlibRuntime uses PHP helpers only (#13347 follow-up) #13858

Category

php-in-php / runtime-shrink · refs #1492, follow-up #13347

Problem

lib/JIT/Builtin/StringZlib.php still dlopens libz.so via FFI in preloadLibz() for MCJIT symbol preload. After #13347, embed and standalone AOT route through ZlibRuntime → ZlibJitHelper PHP (VmZlibCore) — no inline libz LLVM remains. GzStreamRuntime also calls StringZlib::preloadLibz() unnecessarily.

C / FFI to shrink

• StringZlib::preloadLibz() dlopen block (~lines 29–54)
• GzStreamRuntime::implement() call to StringZlib::preloadLibz()

PHP SSOT target

• ZlibRuntime / GzStreamRuntime compile PHP helpers only; no host libz preload

Repro / verify

grep -n preloadLibz lib/JIT/Builtin/StringZlib.php lib/JIT/Builtin/GzStreamRuntime.php
./script/docker-exec.sh -- vendor/bin/phpunit --filter ZlibRuntimeShrink
make bootstrap-selfhost-vm-driver-execute-probe

Done when

• preloadLibz deleted; StringZlib has no FFI::cdef / dlopen
• ZlibRuntimeShrinkTest guards absence of dlopen
• zlib JIT/AOT smoke green