Web: Dynamic isset/empty on $_GET and $_POST keys in JIT

[PurHur]

Problem

IssetHelper optimizes isset($_GET['key']) via SuperglobalInit::compileTimeOffsetIsSet when the key is a string literal. Non-literal keys and runtime-populated superglobals need LLVM hashtable offsetIsSet calls.

Errors today:

• isset() on superglobals only supports a string literal key in this compiler build

VM tests (web_isset_get.phpt) pass; JIT compliance may differ.

Goal

isset($_GET[$param]) and empty($_GET['missing']) work when superglobals are runtime-filled.

Tasks

• JIT: __hashtable__offsetIsSet for sg_GET / sg_POST globals
• empty() lowering consistent with isset
• Remove or gate compile-time-only fast path behind optimization flag
• PHPT under test/compliance for JIT mode

Depends on

• Web: Runtime-populated superglobals for JIT and AOT (per-request $_GET/$_POST) #49 Runtime superglobals

Files

• lib/JIT/IssetHelper.php
• lib/JIT/SuperglobalInit.php