Copyright	2018 Simon Shine
License	MIT
Maintainer	Simon Shine <shreddedglory@gmail.com>
Safe Haskell	None
Language	Haskell2010

EVM.Opcode.Labelled

Description

This module exposes the LabelledOpcode type for expressing Ethereum VM opcodes with labelled jumps. Plain Ethereum VM Opcodes are not so ergonomic because one has to know the exact byte offset of the target JUMPDEST.

With Opcode the byte offset is pushed to the stack via PUSH, but the offset to the JUMPDEST depends on all occurrences of PUSH prior to the label, including the PUSH to the label itself.

Synopsis

type Label = Text
type LabelledOpcode = Opcode' Label
data TranslateError = TranslateError {
- translateErrorMissingJumpdests :: [Label]
- translateErrorDuplicateJumpdests :: [Label]
}
translate :: [LabelledOpcode] -> Either TranslateError [PositionalOpcode]
labelPositions :: [LabelledOpcode] -> Either TranslateError (Map Label Position)

Documentation

type Label = Text Source #

For now, all labels are Text.

type LabelledOpcode = Opcode' Label Source #

LabelledOpcodes use Label to represent jumps.

In particular, JUMP "name", JUMPI "name" and JUMPDEST "name".

All other opcodes remain the same.

data TranslateError Source #

Translation of LabelledOpcodes into PositionalOpcodes may fail if a jump is made to a non-occurring JUMPDEST or a JUMPDEST occurs twice.

Constructors

TranslateError
Fields translateErrorMissingJumpdests :: [Label] translateErrorDuplicateJumpdests :: [Label]

Instances

Instances details

Eq TranslateError Source #
Instance details Defined in EVM.Opcode.Labelled Methods (==) :: TranslateError -> TranslateError -> Bool # (/=) :: TranslateError -> TranslateError -> Bool #
Show TranslateError Source #
Instance details Defined in EVM.Opcode.Labelled Methods showsPrec :: Int -> TranslateError -> ShowS # show :: TranslateError -> String # showList :: [TranslateError] -> ShowS #

translate :: [LabelledOpcode] -> Either TranslateError [PositionalOpcode] Source #

Replace all labels with absolute positions.

Positions are calculated by fixed-point iteration to account for variable sizes of jumps. Labelled jumps don't have a size defined, the size of a positional jump depends on the address being jumped to.

For example, if jumping to the JUMPDEST on the 256th position in a [LabelledOpcode], this requires a PUSH2 instruction which uses an additional byte, which pushes the JUMPDEST one byte ahead.

labelPositions :: [LabelledOpcode] -> Either TranslateError (Map Label Position) Source #

Extract a Map Label Position that describes where each JUMPDEST is located, taking into account the sizes of all prior opcodes.