Stdlib: ext/dom — DOMDocument/DOMElement XML tree API (ext/dom parity)

[PurHur]

Category

stdlib

Problem

XML/HTML processing via DOMDocument / DOMElement (ext/dom) is missing (class_exists('DOMDocument') → false). Feeds, config parsers, RSS readers, and PHPUnit-style tools expect the DOM OOP API — not only string helpers like strip_tags().

Verified Jun 2026:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php -r "var_export(class_exists(\"DOMDocument\"));"
php -r "var_export(class_exists(\"DOMDocument\"));"
'
# VM: false · Zend (dom ext): true

php-src reference

• php/php-src ext/dom/php_dom.c — dom_document_class_entry, class registration
• php/php-src ext/dom/document.c — loadXML, loadHTML, saveXML, createElement
• php/php-src ext/dom/node.c — appendChild, getElementsByTagName, attributes
• php/php-src ext/dom/domexception.c — DOMException

Repro (failure today)

<?php
$doc = new DOMDocument();
$doc->loadXML('<root><item id="1">a</item></root>');
$item = $doc->getElementsByTagName('item')->item(0);
echo $item->getAttribute('id'), $item->textContent, "\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php repro_dom_load_xml.php
php bin/vm.php repro_dom_load_xml.php 2>&1 | head -3
'

Runtime	Output
Zend (ext/dom)	1a
bin/vm.php	Class "DOMDocument" not found

Scope (this repo)

Layer	Path	Notes
Module	ext/dom/Module.php (new)	Register DOMDocument, DOMElement, DOMNode, DOMNodeList, DOMException
VM v1	ext/dom/VmDom.php	libxml2 via thin FFI/trampoline (Docker image libxml2) — no large C DOM logic in runtime/
Methods v1	loadXML, saveXML, createElement, getElementsByTagName, item, getAttribute, textContent, appendChild
Phase 2	loadHTML, XPath, DOMDocumentFragment (#6317)	separate issues OK
Tests	test/compliance/cases/stdlib/dom_document_load_xml.phpt	@requires extension dom on Zend leg
Matrix	script/capability-matrix.php	VM yes; JIT/AOT defer

PHP-in-PHP: DOM tree semantics in ext/dom/ PHP classes; C limited to libxml2 call trampoline if PHP cannot link libxml2 directly.

Done when

• Repro prints 1a on VM in Docker (php-compiler:22.04-dev with libxml2)
• Malformed XML: policy matches Zend (fatal or DOMException — document choice in PHPT)
• class_exists('DOMDocument') true; instanceof DOMNode works for elements
• ./script/ci-fast.sh --filter dom_document_load_xml green
• Capability matrix documents dom classes (VM yes)

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter dom_document_load_xml'

Related

• Stdlib: json_encode() flags and JSON_* constants (ext/json parity, phase 2 of #3267) #3281 JSON (orthogonal) · Stdlib: DOMDocumentFragment — createDocumentFragment/appendChild missing (ext/dom/php_dom.c, phase 2 #3326) #6317 DOMDocumentFragment · Stdlib: ext/dom — DOMDocument/DOMElement XML tree API (ext/dom parity) #3326 parent ext/dom epic · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 Composer/XML tooling

[PurHur]

claim: PHP Compiler Ext — DOM & XML — starting this run (DOMDocument loadHTML/saveHTML user-script AOT bridge)

[PurHur]

Blocker handoff — DOMDocument::loadHTML()/saveHTML() user-script AOT (#3326)

Claim: PHP Compiler Ext — DOM & XML — this run investigated loadHTML/saveHTML AOT gap on master.

Verified (master, Docker)

Repro	VM	JIT	AOT
test/repro/maintainer_gap_dom_create_element_aot.php	p	p	p exit 0 (#17391 closed)
test/repro/dom_loadhtml_comment_siblings.php	ok	ok	Call to undefined method DOMDocument::loadhtml() (before bridge)
test/repro/maintainer_gap_dom_loadhtml_aot.php (draft)	load_ok	load_ok	SIGABRT exit 134 (after registering DomInstanceMethod proxy)

new DOMDocument() alone succeeds under AOT; failure is first DOM instance method needing real ObjectEntry + DomRegistry (not direct-LLVM createElement).

Root cause (narrowed)

User-script AOT defers nested VmDomInstanceInvoke (DomInstanceMethodJit::shouldDeferToVmClassMethodLowering). Only createElement has a dedicated LLVM leaf (JitDomCreateElement). Registering loadhtml/savehtml via DomInstanceMethod + DomInstanceMethodUserScriptLlvm compiles and links, but runtime aborts in the main-module helper — same class as pre-#17397 VmDomInstanceInvoke (VariableObject::entry / __object__* vs ObjectEntry mismatch). Split-TU JitVmHelperLink path also aborts in standalone binary (MCJIT OK).

Next steps

1. Dedicated LLVM leaf for loadHTML/saveHTML that calls VmDom::loadHTML/saveHTML via a minimal helper resolving ObjectEntry from native __object__* (pattern: commit 17672 for createElement assignment, but must reach DomRegistry).
2. Or VmClassMethod JIT lowering for DocumentLoadHTML/DocumentSaveHTML (currently VmClassMethod::call throws).
3. Do not merge PR WIP: DOM AOT createElement property fetch — runtime slot dispatch (#17391) #17788 — regresses createElement AOT per prior handoff.

No merge this run — needs bridge/ObjectEntry resolution fix before AOT execute tier is green.

[PurHur]

claim: PHP Compiler Ext — DOM & XML — starting this run (DOMDocument::load/loadHTML/loadXML user-script AOT via DomInstanceMethod bridge)

[PurHur]

Run handoff (2026-07-11)

Verified green on master:

• maintainer_gap_dom_create_element_aot.php — VM/JIT/AOT prints p, exit 0
• test/fixtures/aot/cases/dom_create_element.phpt — execute tier green via php bin/compile.php

Closed PR #17788 — branch regressed AOT (SEGV); master already fixes #17391.

Attempted: user-script AOT registration for DOMDocument::load/loadXML/loadHTML via DomInstanceMethod bridge. Compile succeeds; runtime abort (134) when bridge invokes — same #16075 class as #17331 loadHTML probe (native __object__ → ObjectEntry in VmDomInstanceInvoke).

Next step for load*:

1. Either fix VariableObject::entry() / __value__readObject for AOT-constructed DOMDocument before VmDom dispatch, OR
2. Dedicated LLVM lowering per method (like JitDomCreateElement) that avoids nested helper ObjectEntry reads.

JIT path for loadXML/loadHTML is green after dispatch wiring (tested on WIP branch).

[PurHur]

Merged #17903 — `DOMElement::tagName` slot initialized on `createElement()` / `createElementNS()`; VM/JIT/AOT repro `maintainer_gap_dom_element_tag_name_jit.php` prints `p:p`. Load/loadHTML user-script AOT bridge still blocked (#16075) — handoff comment above remains accurate for that subtree.