Use bytes encoding to make the mapping

mythril/ether/soliditycontract.py

@@ -3,6 +3,7 @@ from mythril.ether.ethcontract import ETHContract
 from mythril.ether.util import *
 from mythril.exceptions import NoContractFoundError
 
+
 class SourceMapping:
 
     def __init__(self, solidity_file_idx, offset, length, lineno):
@@ -91,8 +92,7 @@ class SolidityContract(ETHContract):
 
             if len(mapping) > 2 and len(mapping[2]) > 0:
                 idx = int(mapping[2])
-
+            lineno = self.solidity_files[idx].data.encode('utf-8')[0:offset].count('\n'.encode('utf-8')) + 1
-            lineno = self.solidity_files[idx].data[0:offset].count('\n') + 1
 
             self.mappings.append(SourceMapping(idx, offset, length, lineno))
 

mythril/support/truffle.py

@@ -76,7 +76,7 @@ def analyze_truffle_project(args):
                     if len(mapping) > 2 and len(mapping[2]) > 0:
                         idx = int(mapping[2])
 
-                    lineno = source[0:offset].count('\n') + 1
+                    lineno = source.encode('utf-8')[0:offset].count('\n'.encode('utf-8')) + 1
 
                     mappings.append(SourceMapping(idx, offset, length, lineno))