diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/wasm/wasm.cpp | 27 |
1 files changed, 11 insertions, 16 deletions
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp index 648a25d9e..74b944bb6 100644 --- a/src/wasm/wasm.cpp +++ b/src/wasm/wasm.cpp @@ -948,23 +948,18 @@ void RefCast::finalize() { return; } - // Do not unnecessarily lose non-nullability info. We could leave this for - // optimizations, but doing it here as part of finalization/refinalization - // ensures that type information flows through in an optimal manner and can be - // used as soon as possible. - if (ref->type.isNonNullable() && type.isNullable()) { - type = Type(type.getHeapType(), NonNullable); - } - - // Do not unnecessarily lose heap type info, as above for nullability. Note - // that we must check if the ref has a heap type, as we reach this before - // validation, which will error if the ref does not in fact have a heap type. - // (This is a downside of propagating type information here, as opposed to - // leaving it for an optimization pass.) - if (ref->type.isRef() && - HeapType::isSubType(ref->type.getHeapType(), type.getHeapType())) { - type = Type(ref->type.getHeapType(), type.getNullability()); + // We reach this before validation, so the input type might be totally wrong. + // Return early in this case to avoid doing the wrong thing below. + if (!ref->type.isRef()) { + return; } + + // Do not unnecessarily lose type information. We could leave this for + // optimizations (and indeed we do a more powerful version of this in + // OptimizeInstructions), but doing it here as part of + // finalization/refinalization ensures that type information flows through in + // an optimal manner and can be used as soon as possible. + type = Type::getGreatestLowerBound(type, ref->type); } void BrOn::finalize() { |