Added JUMP analysis (WIP)

vm/analysis.go

@@ -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
+}