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71 lines (56 loc) · 1.54 KB
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Copy pathop.go
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71 lines (56 loc) · 1.54 KB
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package op
import (
"bytes"
"encoding/binary"
"fmt"
"github.com/derekparker/delve/dwarf/util"
)
const (
DW_OP_addr = 0x3
DW_OP_call_frame_cfa = 0x9c
DW_OP_plus = 0x22
DW_OP_consts = 0x11
)
type stackfn func(*bytes.Buffer, []int64, int64) ([]int64, error)
var oplut = map[byte]stackfn{
DW_OP_call_frame_cfa: callframecfa,
DW_OP_plus: plus,
DW_OP_consts: consts,
DW_OP_addr: addr,
}
func ExecuteStackProgram(cfa int64, instructions []byte) (int64, error) {
stack := make([]int64, 0, 3)
buf := bytes.NewBuffer(instructions)
for ocfaode, err := buf.ReadByte(); err == nil; ocfaode, err = buf.ReadByte() {
fn, ok := oplut[ocfaode]
if !ok {
return 0, fmt.Errorf("invalid instruction %#v", ocfaode)
}
stack, err = fn(buf, stack, cfa)
if err != nil {
return 0, err
}
}
return stack[len(stack)-1], nil
}
func callframecfa(buf *bytes.Buffer, stack []int64, cfa int64) ([]int64, error) {
return append(stack, int64(cfa)), nil
}
func addr(buf *bytes.Buffer, stack []int64, cfa int64) ([]int64, error) {
return append(stack, int64(binary.LittleEndian.Uint64(buf.Next(8)))), nil
}
func plus(buf *bytes.Buffer, stack []int64, cfa int64) ([]int64, error) {
if len(stack) == 1 {
return stack, nil
}
var (
slen = len(stack)
digits = stack[slen-2 : slen]
st = stack[:slen-2]
)
return append(st, digits[0]+digits[1]), nil
}
func consts(buf *bytes.Buffer, stack []int64, cfa int64) ([]int64, error) {
num, _ := util.DecodeSLEB128(buf)
return append(stack, num), nil
}