asm

Documentation

Overview

Package asm provides support for dealing with EVM assembly instructions (e.g., disassembling them).

Source Files

Each file provides the following features.

• asm.go: provides instruction iterators for EVM assembly instructions.
• compiler.go: provides a compiler which compiles input tokens and returns EVM binaries.
• lexer.go: provides the basic construct for parsing source code and turning them into tokens.

Index

• Constants
• func Disassemble(script []byte) ([]string, error)
• func Lex(source []byte, debug bool) <-chan token
• func NewInstructionIterator(code []byte) *instructionIterator
• func PrintDisassembled(code string) error
• type Compiler
  • func NewCompiler(debug bool) *Compiler
  • func (c *Compiler) Compile() (string, []error)
  • func (c *Compiler) Feed(ch <-chan token)

Constants

const (
	Numbers            = "1234567890"                                           // characters representing any decimal number
	HexadecimalNumbers = Numbers + "aAbBcCdDeEfF"                               // characters representing any hexadecimal
	Alpha              = "abcdefghijklmnopqrstuwvxyzABCDEFGHIJKLMNOPQRSTUWVXYZ" // characters representing alphanumeric
)

Functions

func Disassemble

func Disassemble(script []byte) ([]string, error)

Return all disassembled EVM instructions in human-readable format.

func Lex

func Lex(source []byte, debug bool) <-chan token

lex lexes the program by name with the given source. It returns a channel on which the tokens are delivered.

func NewInstructionIterator

func NewInstructionIterator(code []byte) *instructionIterator

Create a new instruction iterator.

func PrintDisassembled

func PrintDisassembled(code string) error

Pretty-print all disassembled EVM instructions to stdout.

Types

type Compiler

type Compiler struct {
	// contains filtered or unexported fields
}

Compiler contains information about the parsed source and holds the tokens for the program.

func NewCompiler

func NewCompiler(debug bool) *Compiler

newCompiler returns a new allocated compiler.

func (*Compiler) Compile

func (c *Compiler) Compile() (string, []error)

Compile compiles the current tokens and returns a binary string that can be interpreted by the EVM and an error if it failed.

compile is the second stage in the compile phase which compiles the tokens to EVM instructions.

func (*Compiler) Feed

func (c *Compiler) Feed(ch <-chan token)

Feed feeds tokens in to ch and are interpreted by the compiler.

feed is the first pass in the compile stage as it collects the used labels in the program and keeps a program counter which is used to determine the locations of the jump dests. The labels can than be used in the second stage to push labels and determine the right position.