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Merged
stevenfontanella merged 2 commits into from
Sep 23, 2026
+51 −22
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Allow struct.wait expected value to be a supertype #9139

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0624377
Fix allowing supertypes as expected value in struct.wait
stevenfontanella Sep 22, 2026
541d85b
Update comments
stevenfontanella Sep 23, 2026
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6 changes: 5 additions & 1 deletion src/ir/subtype-exprs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -390,7 +390,11 @@ struct SubtypingDiscoverer : public OverriddenVisitor<SubType> {
return;
}
const auto& fields = curr->ref->type.getHeapType().getStruct().fields;
self()->noteSubtype(curr->expected, fields[curr->index].type);
auto expectedType = fields[curr->index].type;
if (expectedType.isRef()) {
expectedType = Type(HeapTypes::eq.getBasic(Shared), Nullable);
}
self()->noteSubtype(curr->expected, expectedType);
}
void visitWaitqueueNew(WaitqueueNew* curr) {}
void visitWaitqueueNotify(WaitqueueNotify* curr) {
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13 changes: 0 additions & 13 deletions src/passes/TypeRefining.cpp
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Expand Up @@ -568,19 +568,6 @@ struct TypeRefining : public Pass {
curr->replacement = fixType(curr->replacement, fieldType);
}

void visitStructWait(StructWait* curr) {
if (curr->ref->type == Type::unreachable) {
return;
}
auto type = curr->ref->type.getHeapType();
if (type.isBottom()) {
return;
}

auto fieldType = type.getStruct().fields[curr->index].type;
curr->expected = fixType(curr->expected, fieldType);
}

bool refinalize = false;

// Fix up a given value so it fits into the type the location it is
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5 changes: 4 additions & 1 deletion src/wasm/wasm-validator.cpp
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Expand Up @@ -3739,8 +3739,11 @@ void FunctionValidator::visitStructWait(StructWait* curr) {
return;
}

auto expectedType = field.type.isRef()
? Type(HeapTypes::eq.getBasic(Shared), Nullable)
: field.type;
shouldBeSubType(curr->expected->type,
field.type,
expectedType,
curr,
"struct.wait expected value must match the field immediate");
}
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49 changes: 42 additions & 7 deletions test/lit/passes/type-refining-gufa-rmw.wast
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Expand Up @@ -436,6 +436,20 @@
;; NRML-NEXT: )
;; NRML-NEXT: )
;; NRML-NEXT: (drop
;; NRML-NEXT: (block ;; (replaces unreachable StructCmpxchg we can't emit)
;; NRML-NEXT: (drop
;; NRML-NEXT: (unreachable)
;; NRML-NEXT: )
;; NRML-NEXT: (drop
;; NRML-NEXT: (local.get $struct)
;; NRML-NEXT: )
;; NRML-NEXT: (drop
;; NRML-NEXT: (local.get $struct)
;; NRML-NEXT: )
;; NRML-NEXT: (unreachable)
;; NRML-NEXT: )
;; NRML-NEXT: )
;; NRML-NEXT: (drop
;; NRML-NEXT: (struct.wait $struct 0
;; NRML-NEXT: (local.get $struct)
;; NRML-NEXT: (unreachable)
Expand Down Expand Up @@ -463,15 +477,24 @@
;; GUFA-NEXT: )
;; GUFA-NEXT: )
;; GUFA-NEXT: (drop
;; GUFA-NEXT: (block ;; (replaces unreachable StructCmpxchg we can't emit)
;; GUFA-NEXT: (drop
;; GUFA-NEXT: (unreachable)
;; GUFA-NEXT: )
;; GUFA-NEXT: (drop
;; GUFA-NEXT: (local.get $struct)
;; GUFA-NEXT: )
;; GUFA-NEXT: (drop
;; GUFA-NEXT: (local.get $struct)
;; GUFA-NEXT: )
;; GUFA-NEXT: (unreachable)
;; GUFA-NEXT: )
;; GUFA-NEXT: )
;; GUFA-NEXT: (drop
;; GUFA-NEXT: (struct.wait $struct 0
;; GUFA-NEXT: (local.get $struct)
;; GUFA-NEXT: (unreachable)
;; GUFA-NEXT: (block (result (ref null (shared none)))
;; GUFA-NEXT: (drop
;; GUFA-NEXT: (local.get $struct)
;; GUFA-NEXT: )
;; GUFA-NEXT: (ref.null (shared none))
;; GUFA-NEXT: )
;; GUFA-NEXT: (local.get $struct)
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stevenfontanella marked this conversation as resolved.
;; GUFA-NEXT: (i64.const -1)
;; GUFA-NEXT: )
;; GUFA-NEXT: )
Expand All @@ -492,7 +515,19 @@
(local.get $struct)
)
)
;; Likewise with struct.wait.
;; The fixup to null does *not* happen for the `expected` ref of a cmpxchg,
;; because the expected value is allowed to be a supertype of the field's
;; type. i.e. (local.get $struct) remains valid here even after the field's
;; type is refined.
(drop
(struct.atomic.rmw.cmpxchg acqrel acqrel $struct 0
(unreachable)
(local.get $struct)
(local.get $struct)
)
)
;; Ditto for struct.wait, the `expected` ref may remain a supertype and
;; doesn't need to be fixed up.
(drop
(struct.wait $struct 0
(local.get $struct)
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