General purpose instructions for bytes

[kwannoel]

Part of https://gitlab.com/mukn/glow/-/issues/80.

Features

Batch 1 (Merged: https://github.com/fare/gerbil-ethereum/pull/46)

• [x] Methods for known-size bytes
  • [x] Compat with bytes larger than EVM Word
  • [x] Store at free memory pointer
  • [x] Load at free memory pointer
  • [x] Push for large bytes
• [x] Unit tests
• [x] Integration tests
• [x] Invariant assertions

Batch 2 (WIP: https://github.com/fare/gerbil-ethereum/pull/50)

• [ ] Call by reference methods (by storing offset, length on stack)
• [ ] Static offset methods for load, store. Glow compiler uses mstoreat, mloadat.
• [ ] Support types with have variable sizes during runtime. For example, given a Bytestring with a UInt64 length, during compile time we do not know the actual length / contents of the bytestring. instead we generate instructions to store the length: - on stack is just takes up a slot. - in memory it takes up 8bytes. And use it to decode the contents: - LOAD: Use the offset and length on stack to retrieve the entire bytestring from memory - STORE: Use length on stack to store bytestring in memory
• [ ] memcpy
• [ ] Hashing
• [ ] calldataload, calldatacopy.
• [ ] Limit memory offset to 16/24 bytes due to gas limits, rather than 32.

Batch 3

• [ ] Integrate with existing EVM-Types - Extend? Create new types?
  • [ ] Either use .box? directly to handle boxed / unboxed types
  • [ ] or use it implicitly, with a general .evm<- method for marshalling data to EVM.

Batch 4

• [ ] Handle singletons.
• [ ] Benchmark gas for methods
• [ ] Support for marshalling? (further investigation needed)