Add "builtin" macros to the assembly

[SamWilsn]

Add a couple constant functions to the assembly to make it easier to write. For example (signatures to be bike-shedded):

• selector(...)
• include(...)

selector(...)

Description

selector(...) is replaced by the function selector of the given solidity function signature.

Example

push4 selector("updatePool(address)")    ; actually pushes 0x7b46c54f
eq
push :label 
jumpi

include(...)

include(...) is replaced by the opcodes (and constants, etc) from the given path. Only valid outside of an opcode.

Example

main.evm

push :hello
include("other.evm")

other.evm

jumpdest :hello
stop

Output

push :hello
jumpdest :hello
stop

[SamWilsn]

Should we differentiate between functions, like selector() that compute a value, and include() which copies opcodes?

[lightclient]

We could use %include "..." instead?

[lightclient]

There's also two possible use cases here:

1. Separating code logic - in which case, the code should not have been processed yet
2. Writing a contract deploy wrapper - here, the code should have been processed so the label values are filled in.

I'm inclined for include(...) to do the first, but not certain how to handle the second. assemble(...) maybe? include_assembled(...)?

[SamWilsn]

I think there are actually three cases:

1. Unassembled instructions, for organization/reuse.
2. Assembled instructions, for initcode.
3. Copy bytes, for including the output of other tools, special data/constants, etc.

I like include(...) for (1), and maybe include_bytes(...) or include_hex(...) for (3).

As for (2)... I think I'm partial to include_asm or include_assembled.

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I think we want user-defined macros that generate instructions to look the same as the include macros. I don't know if that means using a % or something else. I guess as long as we're consistent?