Question: How to get the size of a type during LLVM generation?

[EricLBuehler]

Hello everyone,

I am creating a programming language that will have tagged enums. To do this, I need to find the largest element. The way to do this (to my knowledge) is by finding the width of each variant.

I know how to do this for IntType (using the get_bit_width method), however, I cannot find how to do this with PointerType, VectorType, and FloatType. I realize that getting the width of PointerType is likely out of the scope of LLVM in general and would need to associated with the target. However, it seems strange to me that FloatType has no get_bit_width method?

In addition, how would I do this for VectorType? This type has no static length, so there must be another way?

Thank you!

[TheDan64]

What about the size_of method? You'd get a runtime value but that's maybe expected?

[EricLBuehler]

The size_of method gets the size at runtime, but I need it at compile time to determine the largest variant. I would appreciate your guidance on how to find the length of an ArrayType (although I could track this), width of FloatType and width of PointerType.

[TheDan64]

@EricLBuehler How did you solve this? For anyone from the future searching for the same answer

[EricLBuehler]

I solved this by:

• Tracking the type, and therefore, the width of the FloatType.
• Tracking the ArrayType length.
• Keeping track of the target architecture PointerType width.

They all revolve around tracking various metadata.