From b8843a2dfac11c15925df57bb5929137f0f7e0bc Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Thu, 23 Jul 2020 13:07:21 +0300
Subject: [PATCH] vm: make offset in PUSHA relative

Follow neo-project/neo-vm#317 .
---
 pkg/compiler/codegen.go |  7 +------
 pkg/vm/vm.go            | 13 ++++---------
 pkg/vm/vm_test.go       |  4 ++--
 3 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/pkg/compiler/codegen.go b/pkg/compiler/codegen.go
index c63499bd1..b0f27b006 100644
--- a/pkg/compiler/codegen.go
+++ b/pkg/compiler/codegen.go
@@ -1535,12 +1535,7 @@ func (c *codegen) writeJumps(b []byte) error {
 			if int(index) > len(c.l) {
 				return fmt.Errorf("unexpected label number: %d (max %d)", index, len(c.l))
 			}
-			var offset int
-			if op == opcode.PUSHA {
-				offset = c.l[index]
-			} else {
-				offset = c.l[index] - nextIP + 5
-			}
+			offset := c.l[index] - nextIP + 5
 			if offset > math.MaxInt32 || offset < math.MinInt32 {
 				return fmt.Errorf("label offset is too big at the instruction %d: %d (max %d, min %d)",
 					nextIP-5, offset, math.MaxInt32, math.MinInt32)
diff --git a/pkg/vm/vm.go b/pkg/vm/vm.go
index bd5ab19fc..1d780ad89 100644
--- a/pkg/vm/vm.go
+++ b/pkg/vm/vm.go
@@ -192,16 +192,14 @@ func (v *VM) PrintOps() {
 				opcode.JMPGT, opcode.JMPGE, opcode.JMPLE, opcode.JMPLT,
 				opcode.JMPL, opcode.JMPIFL, opcode.JMPIFNOTL, opcode.CALLL,
 				opcode.JMPEQL, opcode.JMPNEL,
-				opcode.JMPGTL, opcode.JMPGEL, opcode.JMPLEL, opcode.JMPLTL:
+				opcode.JMPGTL, opcode.JMPGEL, opcode.JMPLEL, opcode.JMPLTL,
+				opcode.PUSHA:
 				offset, rOffset, err := v.calcJumpOffset(ctx, parameter)
 				if err != nil {
 					desc = fmt.Sprintf("ERROR: %v", err)
 				} else {
 					desc = fmt.Sprintf("%d (%d/%x)", offset, rOffset, parameter)
 				}
-			case opcode.PUSHA:
-				offset := int32(binary.LittleEndian.Uint32(parameter))
-				desc = fmt.Sprintf("%d (%x)", offset, parameter)
 			case opcode.INITSSLOT:
 				desc = fmt.Sprint(parameter[0])
 			case opcode.INITSLOT:
@@ -535,11 +533,8 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
 		v.estack.PushVal(parameter)
 
 	case opcode.PUSHA:
-		n := int32(binary.LittleEndian.Uint32(parameter))
-		if n < 0 || int(n) > len(ctx.prog) {
-			panic(fmt.Sprintf("invalid pointer offset (%d)", n))
-		}
-		ptr := stackitem.NewPointer(int(n), ctx.prog)
+		n := v.getJumpOffset(ctx, parameter)
+		ptr := stackitem.NewPointer(n, ctx.prog)
 		v.estack.PushVal(ptr)
 
 	case opcode.PUSHNULL:
diff --git a/pkg/vm/vm_test.go b/pkg/vm/vm_test.go
index 359d26488..de76e513f 100644
--- a/pkg/vm/vm_test.go
+++ b/pkg/vm/vm_test.go
@@ -980,8 +980,8 @@ func TestPUSHA(t *testing.T) {
 	t.Run("Negative", getTestFuncForVM(makeProgram(opcode.PUSHA, 0xFF, 0xFF, 0xFF, 0xFF), nil))
 	t.Run("TooBig", getTestFuncForVM(makeProgram(opcode.PUSHA, 10, 0, 0, 0), nil))
 	t.Run("Good", func(t *testing.T) {
-		prog := makeProgram(opcode.PUSHA, 2, 0, 0, 0)
-		runWithArgs(t, prog, stackitem.NewPointer(2, prog))
+		prog := makeProgram(opcode.NOP, opcode.PUSHA, 2, 0, 0, 0)
+		runWithArgs(t, prog, stackitem.NewPointer(3, prog))
 	})
 }