Merge pull request #2487 from OffchainLabs/fix-stylus-prestatetracerbug

Update scopeContext's stack to have correct contract address while tracing for contract calls

arbos/programs/api.go

@@ -137,16 +137,31 @@ func newApiClosures(
 		startGas := am.SaturatingUSub(gasLeft, baseCost) * 63 / 64
 		gas := am.MinInt(startGas, gasReq)
 
-		// Tracing: emit the call (value transfer is done later in evm.Call)
-		if tracingInfo != nil {
-			tracingInfo.Tracer.CaptureState(0, opcode, startGas, baseCost+gas, scope, []byte{}, depth, nil)
-		}
-
 		// EVM rule: calls that pay get a stipend (opCall)
 		if value.Sign() != 0 {
 			gas = am.SaturatingUAdd(gas, params.CallStipend)
 		}
 
+		// Tracing: emit the call (value transfer is done later in evm.Call)
+		if tracingInfo != nil {
+			var args []uint256.Int
+			args = append(args, *uint256.NewInt(gas))                          // gas
+			args = append(args, *uint256.NewInt(0).SetBytes(contract.Bytes())) // to address
+			if opcode == vm.CALL {
+				args = append(args, *uint256.NewInt(0).SetBytes(value.Bytes())) // call value
+			}
+			args = append(args, *uint256.NewInt(0))                  // memory offset
+			args = append(args, *uint256.NewInt(uint64(len(input)))) // memory length
+			args = append(args, *uint256.NewInt(0))                  // return offset
+			args = append(args, *uint256.NewInt(0))                  // return size
+			s := &vm.ScopeContext{
+				Memory:   util.TracingMemoryFromBytes(input),
+				Stack:    util.TracingStackFromArgs(args...),
+				Contract: scope.Contract,
+			}
+			tracingInfo.Tracer.CaptureState(0, opcode, startGas, baseCost+gas, s, []byte{}, depth, nil)
+		}
+
 		var ret []byte
 		var returnGas uint64
 

arbos/util/tracing.go

@@ -56,11 +56,8 @@ func (info *TracingInfo) RecordEmitLog(topics []common.Hash, data []byte) {
 	for _, topic := range topics {
 		args = append(args, HashToUint256(topic)) // topic: 32-byte value. Max topics count is 4
 	}
-	memory := vm.NewMemory()
-	memory.Resize(size)
-	memory.Set(0, size, data)
 	scope := &vm.ScopeContext{
-		Memory:   memory,
+		Memory:   TracingMemoryFromBytes(data),
 		Stack:    TracingStackFromArgs(args...),
 		Contract: info.Contract,
 	}