Added JUMP analysis (WIP)

2014-11-04 18:17:38 +01:00
parent 78fb2af6f1
commit 8cfbf1836d
1 changed files with 35 additions and 0 deletions
@@ -0,0 +1,35 @@
+package vm
+
+import (
+	"math/big"
+
+	"github.com/ethgo.old/ethutil"
+)
+
+func analyseJumpDests(code []byte) (dests map[int64]*big.Int) {
+	dests = make(map[int64]*big.Int)
+
+	lp := false
+	var lpv *big.Int
+	for pc := int64(0); pc < int64(len(code)); pc++ {
+		var op OpCode = OpCode(code[pc])
+		switch op {
+		case PUSH1, PUSH2, PUSH3, PUSH4, PUSH5, PUSH6, PUSH7, PUSH8, PUSH9, PUSH10, PUSH11, PUSH12, PUSH13, PUSH14, PUSH15, PUSH16, PUSH17, PUSH18, PUSH19, PUSH20, PUSH21, PUSH22, PUSH23, PUSH24, PUSH25, PUSH26, PUSH27, PUSH28, PUSH29, PUSH30, PUSH31, PUSH32:
+			a := int64(op) - int64(PUSH1) + 1
+			if int64(len(code)) > pc+1+a {
+				lpv = ethutil.BigD(code[pc+1 : pc+1+a])
+			}
+
+			pc += a
+			lp = true
+		case JUMP, JUMPI:
+			if lp {
+				dests[pc] = lpv
+			}
+
+		default:
+			lp = false
+		}
+	}
+	return
+}