Added JUMP analysis (WIP)

1 files changed, 35 insertions, 0 deletions

diff --git a/vm/analysis.go b/vm/analysis.go
new file mode 100644
index 000000000..784b55459
--- /dev/null
+++ b/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
+}