mirror of
https://gitlab.com/pulsechaincom/erigon-pulse.git
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270 lines
6.5 KiB
Go
270 lines
6.5 KiB
Go
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package asm
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import (
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"fmt"
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"math/big"
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"os"
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"strings"
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"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/core/vm"
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)
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// Compiler contains information about the parsed source
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// and holds the tokens for the program.
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type Compiler struct {
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tokens []token
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binary []interface{}
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labels map[string]int
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pc, pos int
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debug bool
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}
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// newCompiler returns a new allocated compiler.
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func NewCompiler(debug bool) *Compiler {
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return &Compiler{
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labels: make(map[string]int),
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debug: debug,
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}
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}
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// Feed feeds tokens in to ch and are interpreted by
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// the compiler.
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//
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// feed is the first pass in the compile stage as it
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// collect the used labels in the program and keeps a
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// program counter which is used to determine the locations
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// of the jump dests. The labels can than be used in the
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// second stage to push labels and determine the right
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// position.
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func (c *Compiler) Feed(ch <-chan token) {
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for i := range ch {
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switch i.typ {
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case number:
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num := math.MustParseBig256(i.text).Bytes()
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if len(num) == 0 {
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num = []byte{0}
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}
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c.pc += len(num)
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case stringValue:
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c.pc += len(i.text) - 2
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case element:
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c.pc++
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case labelDef:
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c.labels[i.text] = c.pc
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c.pc++
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case label:
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c.pc += 5
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}
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c.tokens = append(c.tokens, i)
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}
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if c.debug {
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fmt.Fprintln(os.Stderr, "found", len(c.labels), "labels")
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}
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}
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// Compile compiles the current tokens and returns a
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// binary string that can be interpreted by the EVM
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// and an error if it failed.
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//
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// compile is the second stage in the compile phase
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// which compiles the tokens to EVM instructions.
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func (c *Compiler) Compile() (string, []error) {
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var errors []error
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// continue looping over the tokens until
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// the stack has been exhausted.
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for c.pos < len(c.tokens) {
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if err := c.compileLine(); err != nil {
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errors = append(errors, err)
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}
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}
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// turn the binary to hex
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var bin string
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for _, v := range c.binary {
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switch v := v.(type) {
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case vm.OpCode:
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bin += fmt.Sprintf("%x", []byte{byte(v)})
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case []byte:
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bin += fmt.Sprintf("%x", v)
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}
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}
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return bin, errors
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}
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// next returns the next token and increments the
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// position.
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func (c *Compiler) next() token {
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token := c.tokens[c.pos]
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c.pos++
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return token
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}
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// compile line compiles a single line instruction e.g.
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// "push 1", "jump @label".
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func (c *Compiler) compileLine() error {
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n := c.next()
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if n.typ != lineStart {
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return compileErr(n, n.typ.String(), lineStart.String())
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}
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lvalue := c.next()
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switch lvalue.typ {
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case eof:
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return nil
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case element:
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if err := c.compileElement(lvalue); err != nil {
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return err
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}
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case labelDef:
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c.compileLabel()
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case lineEnd:
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return nil
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default:
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return compileErr(lvalue, lvalue.text, fmt.Sprintf("%v or %v", labelDef, element))
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}
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if n := c.next(); n.typ != lineEnd {
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return compileErr(n, n.text, lineEnd.String())
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}
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return nil
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}
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// compileNumber compiles the number to bytes
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func (c *Compiler) compileNumber(element token) (int, error) {
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num := math.MustParseBig256(element.text).Bytes()
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if len(num) == 0 {
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num = []byte{0}
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}
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c.pushBin(num)
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return len(num), nil
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}
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// compileElement compiles the element (push & label or both)
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// to a binary representation and may error if incorrect statements
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// where fed.
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func (c *Compiler) compileElement(element token) error {
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// check for a jump. jumps must be read and compiled
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// from right to left.
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if isJump(element.text) {
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rvalue := c.next()
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switch rvalue.typ {
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case number:
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// TODO figure out how to return the error properly
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c.compileNumber(rvalue)
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case stringValue:
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// strings are quoted, remove them.
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c.pushBin(rvalue.text[1 : len(rvalue.text)-2])
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case label:
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c.pushBin(vm.PUSH4)
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pos := big.NewInt(int64(c.labels[rvalue.text])).Bytes()
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pos = append(make([]byte, 4-len(pos)), pos...)
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c.pushBin(pos)
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default:
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return compileErr(rvalue, rvalue.text, "number, string or label")
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}
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// push the operation
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c.pushBin(toBinary(element.text))
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return nil
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} else if isPush(element.text) {
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// handle pushes. pushes are read from left to right.
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var value []byte
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rvalue := c.next()
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switch rvalue.typ {
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case number:
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value = math.MustParseBig256(rvalue.text).Bytes()
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if len(value) == 0 {
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value = []byte{0}
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}
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case stringValue:
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value = []byte(rvalue.text[1 : len(rvalue.text)-1])
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case label:
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value = make([]byte, 4)
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copy(value, big.NewInt(int64(c.labels[rvalue.text])).Bytes())
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default:
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return compileErr(rvalue, rvalue.text, "number, string or label")
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}
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if len(value) > 32 {
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return fmt.Errorf("%d type error: unsupported string or number with size > 32", rvalue.lineno)
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}
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c.pushBin(vm.OpCode(int(vm.PUSH1) - 1 + len(value)))
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c.pushBin(value)
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} else {
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c.pushBin(toBinary(element.text))
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}
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return nil
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}
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// compileLabel pushes a jumpdest to the binary slice.
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func (c *Compiler) compileLabel() {
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c.pushBin(vm.JUMPDEST)
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}
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// pushBin pushes the value v to the binary stack.
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func (c *Compiler) pushBin(v interface{}) {
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if c.debug {
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fmt.Printf("%d: %v\n", len(c.binary), v)
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}
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c.binary = append(c.binary, v)
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}
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// isPush returns whether the string op is either any of
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// push(N).
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func isPush(op string) bool {
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return op == "push"
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}
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// isJump returns whether the string op is jump(i)
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func isJump(op string) bool {
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return op == "jumpi" || op == "jump"
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}
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// toBinary converts text to a vm.OpCode
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func toBinary(text string) vm.OpCode {
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return vm.StringToOp(strings.ToUpper(text))
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}
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type compileError struct {
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got string
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want string
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lineno int
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}
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func (err compileError) Error() string {
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return fmt.Sprintf("%d syntax error: unexpected %v, expected %v", err.lineno, err.got, err.want)
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}
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func compileErr(c token, got, want string) error {
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return compileError{
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got: got,
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want: want,
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lineno: c.lineno,
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}
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}
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