Is DataLayout::getAlignment for TargetExtType unreachable?

[pmatos]

It looks as though the switch case:

case Type::TargetExtTyID: {
    Type *LayoutTy = cast<TargetExtType>(Ty)->getLayoutType();
    return getAlignment(LayoutTy, abi_or_pref);
  }

in DataLayout.cpp::getAlignment is unreachable due to the initial assert:
assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");.

Type::isSized() has the following case which returns false for TargetExtTyID:

    if (getTypeID() != StructTyID && getTypeID() != ArrayTyID &&
        !isVectorTy() && getTypeID() != TargetExtTyID)
      return false;

Do we need to improve the check in isSized with for example:

if (getTypeID() == TargetExtTyID)
  return getLayoutType()->isSized();

?

[nikic]

Type::isSized() has the following case which returns false for TargetExtTyID:

I think you read this the wrong way around? This is an early-exit if the type is not TargetExt. The actual handling for TargetExt types is in isSizedDerivedType().

[pmatos]

Type::isSized() has the following case which returns false for TargetExtTyID:

I think you read this the wrong way around? This is an early-exit if the type is not TargetExt. The actual handling for TargetExt types is in isSizedDerivedType().

I read it several times to confirm I was correct before creating the issue but only after you pointed out it's an early exit I noticed my error. 🤦🏼

My apologies. Closing.