[JSC] Introduce B3 WasmRefCast / WasmRefTest values #56950

Constellation · 2026-01-21T08:40:52Z

`ea11204`

[JSC] Introduce B3 WasmRefCast / WasmRefTest values
https://bugs.webkit.org/show_bug.cgi?id=305912
rdar://168566739

Reviewed by Keith Miller.

We introduce WasmRefCast and WasmRefTest B3 values. This is another
high-level B3 nodes for WasmGC. This enables data-flow analysis for wasm
GC operations in B3 finally.
The generated code is literally just moved from OMG IR generator to
B3LowerMacros. We introduce ValueKey Value::key CSE support for these
values.

Based on this high-level semantics, we start using it in ReduceStrength.
We make WasmStructGet, WasmStructSet can remove trapping bits based on
input's WasmRefCast. And WasmRefCast can make convert itself to non-nullable
based on subsequent values in the same basic block.

* Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj:
* Source/JavaScriptCore/Sources.txt:
* Source/JavaScriptCore/b3/B3Kind.h:
(JSC::B3::Kind::hasTraps const):
* Source/JavaScriptCore/b3/B3LowerMacros.cpp:
* Source/JavaScriptCore/b3/B3Opcode.h:
* Source/JavaScriptCore/b3/B3ReduceStrength.cpp:
* Source/JavaScriptCore/b3/B3Validate.cpp:
* Source/JavaScriptCore/b3/B3Value.cpp:
(JSC::B3::Value::effects const):
(JSC::B3::Value::key const):
* Source/JavaScriptCore/b3/B3Value.h:
* Source/JavaScriptCore/b3/B3ValueInlines.h:
* Source/JavaScriptCore/b3/B3ValueKey.cpp:
(JSC::B3::ValueKey::materialize const):
* Source/JavaScriptCore/b3/B3ValueKey.h:
* Source/JavaScriptCore/b3/B3ValueKeyInlines.h:
(JSC::B3::ValueKey::ValueKey):
* Source/JavaScriptCore/b3/B3WasmRefTypeCheckValue.cpp: Added.
* Source/JavaScriptCore/b3/B3WasmRefTypeCheckValue.h: Added.
* Source/JavaScriptCore/wasm/WasmOMGIRGenerator.cpp:
(JSC::Wasm::OMGIRGenerator::emitRefTestOrCast):
(JSC::Wasm::OMGIRGenerator::emitCheckOrBranchForCast): Deleted.
* Source/JavaScriptCore/wasm/WasmTypeDefinition.cpp:
(JSC::Wasm::RTT::RTT):
(JSC::Wasm::RTT::tryCreate):
(JSC::Wasm::TypeInformation::createCanonicalRTTForType):
* Source/JavaScriptCore/wasm/WasmTypeDefinition.h:

Canonical link: https://commits.webkit.org/306061@main

77bc15b

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	~~🛠 wpe~~	~~🛠 win~~	⏳ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	~~🧪 wpe-wk2~~	~~🧪 win-tests~~	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	~~🧪 ios-wk2~~	~~🧪 api-mac~~	~~🧪 api-wpe~~		⏳ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	~~🧪 api-mac-debug~~	❌ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	~~🧪 api-ios~~	~~🧪 mac-wk1~~	❌ 🛠 gtk
~~🛠 🧪 jsc-debug-arm64~~	✅ 🛠 vision	~~🧪 mac-wk2~~	❌ 🧪 gtk-wk2
	✅ 🛠 vision-sim	~~🧪 mac-AS-debug-wk2~~	❌ 🧪 api-gtk
	~~🧪 vision-wk2~~	~~🧪 mac-wk2-stress~~	~~🛠 playstation~~
✅ 🛠 🧪 unsafe-merge	~~🛠 tv~~	~~🧪 mac-intel-wk2~~	~~🛠 jsc-armv7~~
	✅ 🛠 tv-sim	~~🛠 mac-safer-cpp~~	~~🧪 jsc-armv7-tests~~
	~~🛠 watch~~
	~~🛠 watch-sim~~

webkit-early-warning-system · 2026-01-21T08:40:58Z

EWS run on previous version of this PR (hash eda956d)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
❌ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	~~🛠 win~~	⏳ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	⏳ 🧪 wpe-wk2	~~🧪 win-tests~~	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	~~🧪 ios-wk2~~	~~🧪 api-mac~~	~~🧪 api-wpe~~		⏳ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	~~🧪 api-mac-debug~~	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	~~🧪 api-ios~~	~~🧪 mac-wk1~~	~~🛠 gtk~~
✅ 🛠 🧪 jsc-debug-arm64	✅ 🛠 vision	~~🧪 mac-wk2~~	~~🧪 gtk-wk2~~
	✅ 🛠 vision-sim	~~🧪 mac-AS-debug-wk2~~	~~🧪 api-gtk~~
	~~🧪 vision-wk2~~	~~🧪 mac-wk2-stress~~	~~🛠 playstation~~
	✅ 🛠 tv	~~🧪 mac-intel-wk2~~	~~🛠 jsc-armv7~~
	~~🛠 tv-sim~~	~~🛠 mac-safer-cpp~~	~~🧪 jsc-armv7-tests~~
	~~🛠 watch~~
	✅ 🛠 watch-sim

webkit-early-warning-system · 2026-01-21T08:47:03Z

EWS run on previous version of this PR (hash d973293)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win	🛠 ios-apple
	✅ 🛠 ios-sim	🛠 mac-AS-debug	✅ 🧪 wpe-wk2	❌ 🧪 win-tests	🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe		✅ 🛠 vision-apple
	⏳ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-debug-arm64	✅ 🛠 vision	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2	❌ 🛠 jsc-armv7
	✅ 🛠 tv-sim	❌ 🛠 mac-safer-cpp	❌ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	✅ 🛠 watch-sim

webkit-ews-buildbot · 2026-01-21T11:20:04Z

Safer C++ Build #75642 (`d973293`)

❌ Found 1 failing file with 1 issue. Please address these issues before landing. See WebKit Guidelines for Safer C++ Programming.
(cc @rniwa)

webkit-early-warning-system · 2026-01-22T01:14:58Z

EWS run on previous version of this PR (hash d2d56b4)

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Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
❌ 🧪 style	~~🛠 ios~~	~~🛠 mac~~	~~🛠 wpe~~	~~🛠 win~~	⏳ 🛠 ios-apple
	~~🛠 ios-sim~~	~~🛠 mac-AS-debug~~	~~🧪 wpe-wk2~~	~~🧪 win-tests~~	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	~~🧪 ios-wk2~~	~~🧪 api-mac~~	~~🧪 api-wpe~~		⏳ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	~~🧪 api-mac-debug~~	~~🛠 wpe-cairo-libwebrtc~~
~~🛠 🧪 jsc~~	~~🧪 api-ios~~	~~🧪 mac-wk1~~	~~🛠 gtk~~
~~🛠 🧪 jsc-debug-arm64~~	~~🛠 vision~~	~~🧪 mac-wk2~~	~~🧪 gtk-wk2~~
	~~🛠 vision-sim~~	~~🧪 mac-AS-debug-wk2~~	~~🧪 api-gtk~~
	⏳ 🧪 vision-wk2	~~🧪 mac-wk2-stress~~	~~🛠 playstation~~
	~~🛠 tv~~	~~🧪 mac-intel-wk2~~	~~🛠 jsc-armv7~~
	~~🛠 tv-sim~~	~~🛠 mac-safer-cpp~~	~~🧪 jsc-armv7-tests~~
	~~🛠 watch~~
	~~🛠 watch-sim~~

webkit-early-warning-system · 2026-01-22T01:17:23Z

EWS run on previous version of this PR (hash 7f80ffb)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
❌ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	~~🛠 win~~	✅ 🛠 ios-apple
	~~🛠 ios-sim~~	✅ 🛠 mac-AS-debug	⏳ 🧪 wpe-wk2	~~🧪 win-tests~~	✅ 🛠 mac-apple
✅ 🧪 webkitperl	~~🧪 ios-wk2~~	⏳ 🧪 api-mac	✅ 🧪 api-wpe		✅ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	⏳ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	~~🧪 api-ios~~	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-debug-arm64	~~🛠 vision~~	✅ 🧪 mac-wk2	~~🧪 gtk-wk2~~
	✅ 🛠 vision-sim	~~🧪 mac-AS-debug-wk2~~	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	~~🛠 playstation~~
	✅ 🛠 tv	~~🧪 mac-intel-wk2~~	❌ 🛠 jsc-armv7
	~~🛠 tv-sim~~	~~🛠 mac-safer-cpp~~	❌ 🧪 jsc-armv7-tests
	~~🛠 watch~~
	~~🛠 watch-sim~~

webkit-early-warning-system · 2026-01-22T03:34:43Z

EWS run on previous version of this PR (hash a743328)

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Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	~~🛠 wpe~~	~~🛠 win~~	⏳ 🛠 ios-apple
	~~🛠 ios-sim~~	✅ 🛠 mac-AS-debug	~~🧪 wpe-wk2~~	~~🧪 win-tests~~	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	~~🧪 ios-wk2~~	⏳ 🧪 api-mac	~~🧪 api-wpe~~		⏳ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	⏳ 🧪 api-mac-debug	~~🛠 wpe-cairo-libwebrtc~~
~~🛠 🧪 jsc~~	~~🧪 api-ios~~	~~🧪 mac-wk1~~	~~🛠 gtk~~
✅ 🛠 🧪 jsc-debug-arm64	~~🛠 vision~~	~~🧪 mac-wk2~~	~~🧪 gtk-wk2~~
	~~🛠 vision-sim~~	⏳ 🧪 mac-AS-debug-wk2	~~🧪 api-gtk~~
	⏳ 🧪 vision-wk2	~~🧪 mac-wk2-stress~~	~~🛠 playstation~~
	✅ 🛠 tv	⏳ 🧪 mac-intel-wk2	~~🛠 jsc-armv7~~
	~~🛠 tv-sim~~	~~🛠 mac-safer-cpp~~	~~🧪 jsc-armv7-tests~~
	~~🛠 watch~~
	~~🛠 watch-sim~~

webkit-early-warning-system · 2026-01-22T03:36:25Z

EWS run on previous version of this PR (hash f7d8aeb)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	~~🛠 win~~	⏳ 🛠 ios-apple
	~~🛠 ios-sim~~	✅ 🛠 mac-AS-debug	⏳ 🧪 wpe-wk2	~~🧪 win-tests~~	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	~~🧪 ios-wk2~~	⏳ 🧪 api-mac	~~🧪 api-wpe~~		⏳ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	⏳ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
~~🛠 🧪 jsc~~	~~🧪 api-ios~~	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-debug-arm64	~~🛠 vision~~	~~🧪 mac-wk2~~	⏳ 🧪 gtk-wk2
	~~🛠 vision-sim~~	~~🧪 mac-AS-debug-wk2~~	✅ 🧪 api-gtk
	⏳ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	~~🛠 playstation~~
	✅ 🛠 tv	~~🧪 mac-intel-wk2~~	❌ 🛠 jsc-armv7
	~~🛠 tv-sim~~	~~🛠 mac-safer-cpp~~	❌ 🧪 jsc-armv7-tests
	~~🛠 watch~~
	~~🛠 watch-sim~~

webkit-early-warning-system · 2026-01-22T04:29:27Z

EWS run on previous version of this PR (hash 5ff9619)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	~~🛠 win~~	✅ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	~~🧪 wpe-wk2~~	~~🧪 win-tests~~	✅ 🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe		✅ 🛠 vision-apple
	⏳ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	⏳ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-debug-arm64	~~🛠 vision~~	✅ 🧪 mac-wk2	~~🧪 gtk-wk2~~
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	~~🛠 playstation~~
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2	❌ 🛠 jsc-armv7
	~~🛠 tv-sim~~	~~🛠 mac-safer-cpp~~	❌ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	~~🛠 watch-sim~~

webkit-early-warning-system · 2026-01-22T06:21:28Z

EWS run on previous version of this PR (hash 7056696)

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Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win	⏳ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	✅ 🧪 win-tests	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe		✅ 🛠 vision-apple
	✅ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-debug-arm64	✅ 🛠 vision	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim	✅ 🛠 mac-safer-cpp	⏳ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	✅ 🛠 watch-sim

webkit-early-warning-system · 2026-01-22T17:35:31Z

EWS run on previous version of this PR (hash ea12212)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win	⏳ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	~~🧪 win-tests~~	✅ 🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe		🛠 vision-apple
	✅ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-debug-arm64	✅ 🛠 vision	🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim	✅ 🛠 mac-safer-cpp	⏳ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	✅ 🛠 watch-sim

kmiller68

r=me if you get rid of the extra subclasses for B3::WasmRefTypeCheckValue

kmiller68 · 2026-01-22T19:41:41Z

Source/JavaScriptCore/b3/B3LowerMacros.cpp

+                BasicBlock* before = m_blockInsertionSet.splitForward(m_block, m_index, &m_insertionSet);
+                BasicBlock* continuation = m_block;
+                m_value->replaceWithIdentity(emitRefTestOrCast(typeCheck, before, continuation));


It seems like most of the time for Casts we wouldn't have to create the continuation. Might be worth a FIXME to only split the block if we're actually inserting new control flow.

kmiller68 · 2026-01-22T20:00:43Z

Source/JavaScriptCore/b3/B3WasmRefTypeCheckValue.h

+    HasRTT = 1 << 5, // Whether m_targetRTT is non-null (vs using targetHeapType)
+};
+
+class WasmRefTypeCheckValue : public Value {


Seems like we can just have WasmRefCast and WasmRefTest share the same WasmRefTypeCheckValue and get rid of the specialized subclasses. Those subclasses don't have anything interesting in them and I think we mostly use different Values subclasses when we need extra fields, which isn't the case here.

That's nice, changed.

kmiller68 · 2026-01-22T20:01:49Z

Source/JavaScriptCore/b3/B3ReduceStrength.cpp

+            };
+
+            if (cast->allowNull()) {
+                // This is really common in J2CL, Java to wasm compiler. When you write a code in Java like,


Might be worth mentioning that this comment is from JS3, it's possible future versions of J2CL in JS4+ lower code differently.

That's good. Changed.

webkit-early-warning-system · 2026-01-22T23:09:45Z

EWS run on previous version of this PR (hash 013402d)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	~~🛠 wpe~~	~~🛠 win~~	🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	❌ 🧪 wpe-wk2	~~🧪 win-tests~~	🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe		🛠 vision-apple
	⏳ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-debug-arm64	❌ 🛠 vision	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	~~🛠 playstation~~
	❌ 🛠 tv	~~🧪 mac-intel-wk2~~	✅ 🛠 jsc-armv7
	❌ 🛠 tv-sim	❌ 🛠 mac-safer-cpp	~~🧪 jsc-armv7-tests~~
	~~🛠 watch~~
	✅ 🛠 watch-sim

webkit-early-warning-system · 2026-01-23T02:49:49Z

EWS run on previous version of this PR (hash b515c3a)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	~~🛠 win~~	⏳ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	~~🧪 wpe-wk2~~	~~🧪 win-tests~~	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	~~🧪 api-wpe~~		⏳ 🛠 vision-apple
	⏳ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	⏳ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc-debug-arm64	✅ 🛠 vision	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	~~🛠 playstation~~
	✅ 🛠 tv	~~🧪 mac-intel-wk2~~	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim	✅ 🛠 mac-safer-cpp	~~🧪 jsc-armv7-tests~~
	~~🛠 watch~~
	✅ 🛠 watch-sim

webkit-early-warning-system · 2026-01-23T07:38:25Z

EWS run on current version of this PR (hash 77bc15b)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	~~🛠 wpe~~	~~🛠 win~~	⏳ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	~~🧪 wpe-wk2~~	~~🧪 win-tests~~	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	~~🧪 ios-wk2~~	~~🧪 api-mac~~	~~🧪 api-wpe~~		⏳ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	~~🧪 api-mac-debug~~	❌ 🛠 wpe-cairo-libwebrtc
✅ 🛠 🧪 jsc	~~🧪 api-ios~~	~~🧪 mac-wk1~~	❌ 🛠 gtk
~~🛠 🧪 jsc-debug-arm64~~	✅ 🛠 vision	~~🧪 mac-wk2~~	❌ 🧪 gtk-wk2
	✅ 🛠 vision-sim	~~🧪 mac-AS-debug-wk2~~	❌ 🧪 api-gtk
	~~🧪 vision-wk2~~	~~🧪 mac-wk2-stress~~	~~🛠 playstation~~
✅ 🛠 🧪 unsafe-merge	~~🛠 tv~~	~~🧪 mac-intel-wk2~~	~~🛠 jsc-armv7~~
	✅ 🛠 tv-sim	~~🛠 mac-safer-cpp~~	~~🧪 jsc-armv7-tests~~
	~~🛠 watch~~
	~~🛠 watch-sim~~

https://bugs.webkit.org/show_bug.cgi?id=305912 rdar://168566739 Reviewed by Keith Miller. We introduce WasmRefCast and WasmRefTest B3 values. This is another high-level B3 nodes for WasmGC. This enables data-flow analysis for wasm GC operations in B3 finally. The generated code is literally just moved from OMG IR generator to B3LowerMacros. We introduce ValueKey Value::key CSE support for these values. Based on this high-level semantics, we start using it in ReduceStrength. We make WasmStructGet, WasmStructSet can remove trapping bits based on input's WasmRefCast. And WasmRefCast can make convert itself to non-nullable based on subsequent values in the same basic block. * Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj: * Source/JavaScriptCore/Sources.txt: * Source/JavaScriptCore/b3/B3Kind.h: (JSC::B3::Kind::hasTraps const): * Source/JavaScriptCore/b3/B3LowerMacros.cpp: * Source/JavaScriptCore/b3/B3Opcode.h: * Source/JavaScriptCore/b3/B3ReduceStrength.cpp: * Source/JavaScriptCore/b3/B3Validate.cpp: * Source/JavaScriptCore/b3/B3Value.cpp: (JSC::B3::Value::effects const): (JSC::B3::Value::key const): * Source/JavaScriptCore/b3/B3Value.h: * Source/JavaScriptCore/b3/B3ValueInlines.h: * Source/JavaScriptCore/b3/B3ValueKey.cpp: (JSC::B3::ValueKey::materialize const): * Source/JavaScriptCore/b3/B3ValueKey.h: * Source/JavaScriptCore/b3/B3ValueKeyInlines.h: (JSC::B3::ValueKey::ValueKey): * Source/JavaScriptCore/b3/B3WasmRefTypeCheckValue.cpp: Added. * Source/JavaScriptCore/b3/B3WasmRefTypeCheckValue.h: Added. * Source/JavaScriptCore/wasm/WasmOMGIRGenerator.cpp: (JSC::Wasm::OMGIRGenerator::emitRefTestOrCast): (JSC::Wasm::OMGIRGenerator::emitCheckOrBranchForCast): Deleted. * Source/JavaScriptCore/wasm/WasmTypeDefinition.cpp: (JSC::Wasm::RTT::RTT): (JSC::Wasm::RTT::tryCreate): (JSC::Wasm::TypeInformation::createCanonicalRTTForType): * Source/JavaScriptCore/wasm/WasmTypeDefinition.h: Canonical link: https://commits.webkit.org/306061@main

webkit-commit-queue · 2026-01-23T07:41:42Z

Committed 306061@main (ea11204): https://commits.webkit.org/306061@main

Reviewed commits have been landed. Closing PR #56950 and removing active labels.

Constellation self-assigned this Jan 21, 2026

Constellation added the JavaScriptCore For bugs in JavaScriptCore, the JS engine used by WebKit, other than kxmlcore issues. label Jan 21, 2026

Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from eda956d to d973293 Compare January 21, 2026 08:46

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Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from d973293 to d2d56b4 Compare January 22, 2026 01:14

Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from d2d56b4 to 7f80ffb Compare January 22, 2026 01:17

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Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from 7f80ffb to a743328 Compare January 22, 2026 03:34

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Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from a743328 to f7d8aeb Compare January 22, 2026 03:36

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Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from f7d8aeb to 5ff9619 Compare January 22, 2026 04:29

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Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from 5ff9619 to 7056696 Compare January 22, 2026 06:21

Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from 7056696 to ea12212 Compare January 22, 2026 17:35

kmiller68 approved these changes Jan 22, 2026

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Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from ea12212 to 013402d Compare January 22, 2026 23:09

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Constellation force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from b515c3a to 77bc15b Compare January 23, 2026 07:38

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webkit-commit-queue force-pushed the eng/JSC-Introduce-B3-WasmRefCast-WasmRefTest-values branch from 77bc15b to ea11204 Compare January 23, 2026 07:41

webkit-commit-queue merged commit ea11204 into WebKit:main Jan 23, 2026

webkit-commit-queue removed the unsafe-merge-queue Applied to send a pull request to merge-queue, but skip building and testing label Jan 23, 2026

[JSC] Introduce B3 WasmRefCast / WasmRefTest values #56950

[JSC] Introduce B3 WasmRefCast / WasmRefTest values #56950

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