Merge pull request #2435 from crytic/fix/evm-printer

Fix bugs in the EVM printer

slither/analyses/evm/convert.py

@@ -178,15 +178,14 @@ def generate_source_to_evm_ins_mapping(evm_instructions, srcmap_runtime, slither
         # In order to compress these source mappings especially for bytecode, the following rules are used:
         # If a field is empty, the value of the preceding element is used.
         # If a : is missing, all following fields are considered empty.
-
         mapping_item = mapping.split(":")
         mapping_item += prev_mapping[len(mapping_item) :]
 
         for i, _ in enumerate(mapping_item):
             if mapping_item[i] == "":
-                mapping_item[i] = int(prev_mapping[i])
+                mapping_item[i] = prev_mapping[i]
 
-        offset, _length, file_id, *_ = mapping_item
+        offset, _, file_id, *_ = mapping_item
         prev_mapping = mapping_item
 
         if file_id == "-1":
@@ -194,8 +193,7 @@ def generate_source_to_evm_ins_mapping(evm_instructions, srcmap_runtime, slither
             # See https://github.com/ethereum/solidity/issues/6119#issuecomment-467797635
             continue
 
-        offset = int(offset)
-        line_number = file_source[0:offset].count("\n".encode("utf-8")) + 1
+        line_number = file_source[0 : int(offset)].count("\n".encode("utf-8")) + 1
 
         # Append evm instructions to the corresponding source line number
         # Note: Some evm instructions in mapping are not necessarily in program execution order

slither/printers/summary/evm.py

@@ -2,8 +2,11 @@
     Module printing evm mapping of the contract
 """
 import logging
+from typing import Union, List, Dict
 
 from slither.printers.abstract_printer import AbstractPrinter
+from slither.core.declarations.function import Function
+from slither.core.declarations.modifier import Modifier
 from slither.analyses.evm import (
     generate_source_to_evm_ins_mapping,
     load_evm_cfg_builder,
@@ -77,6 +80,33 @@ class PrinterEVM(AbstractPrinter):
 
     WIKI = "https://github.com/trailofbits/slither/wiki/Printer-documentation#evm"
 
+    def build_element_node_str(
+        self,
+        element: Union["Modifier", "Function"],
+        contract_pcs: Dict[int, List[int]],
+        contract_cfg,
+    ) -> str:
+        element_file = self.slither.source_code[
+            element.contract_declarer.source_mapping.filename.absolute
+        ].splitlines()
+
+        return_string = ""
+        for node in element.nodes:
+            return_string += green(f"\t\tNode: {node}\n")
+            node_source_line = node.source_mapping.lines[0]
+            return_string += green(
+                f"\t\tSource line {node_source_line}: {element_file[node_source_line - 1].rstrip()}\n"
+            )
+
+            return_string += magenta("\t\tEVM Instructions:\n")
+            node_pcs = contract_pcs.get(node_source_line, [])
+            for pc in node_pcs:
+                return_string += magenta(
+                    f"\t\t\t{hex(pc)}: {contract_cfg.get_instruction_at(pc)}\n"
+                )
+
+        return return_string
+
     def output(self, _filename):
         """
         _filename is not used
@@ -99,53 +129,27 @@ class PrinterEVM(AbstractPrinter):
                 txt += "\tempty contract\n"
                 continue
 
-            contract_file = self.slither.source_code[
-                contract.source_mapping.filename.absolute
-            ].encode("utf-8")
-            with open(contract.source_mapping.filename.absolute, "r", encoding="utf8") as f:
-                contract_file_lines = f.readlines()
-
-            contract_pcs = {}
-            contract_cfg = {}
-
             for function in contract.functions:
                 txt += blue(f"\tFunction {function.canonical_name}\n")
 
-                # CFG and source mapping depend on function being constructor or not
-                if function.is_constructor:
-                    contract_cfg = evm_info["cfg_init", contract.name]
-                    contract_pcs = evm_info["mapping_init", contract.name]
-                else:
-                    contract_cfg = evm_info["cfg", contract.name]
-                    contract_pcs = evm_info["mapping", contract.name]
-
-                for node in function.nodes:
-                    txt += green("\t\tNode: " + str(node) + "\n")
-                    node_source_line = (
-                        contract_file[0 : node.source_mapping.start].count("\n".encode("utf-8")) + 1
-                    )
-                    txt += green(
-                        f"\t\tSource line {node_source_line}: {contract_file_lines[node_source_line - 1].rstrip()}\n"
-                    )
-                    txt += magenta("\t\tEVM Instructions:\n")
-                    node_pcs = contract_pcs.get(node_source_line, [])
-                    for pc in node_pcs:
-                        txt += magenta(f"\t\t\t{hex(pc)}: {contract_cfg.get_instruction_at(pc)}\n")
+                txt += self.build_element_node_str(
+                    function,
+                    evm_info["mapping", contract.name]
+                    if not function.is_constructor
+                    else evm_info["mapping_init", contract.name],
+                    evm_info["cfg", contract.name]
+                    if not function.is_constructor
+                    else evm_info["cfg_init", contract.name],
+                )
 
             for modifier in contract.modifiers:
                 txt += blue(f"\tModifier {modifier.canonical_name}\n")
-                for node in modifier.nodes:
-                    txt += green("\t\tNode: " + str(node) + "\n")
-                    node_source_line = (
-                        contract_file[0 : node.source_mapping.start].count("\n".encode("utf-8")) + 1
-                    )
-                    txt += green(
-                        f"\t\tSource line {node_source_line}: {contract_file_lines[node_source_line - 1].rstrip()}\n"
-                    )
-                    txt += magenta("\t\tEVM Instructions:\n")
-                    node_pcs = contract_pcs.get(node_source_line, [])
-                    for pc in node_pcs:
-                        txt += magenta(f"\t\t\t{hex(pc)}: {contract_cfg.get_instruction_at(pc)}\n")
+
+                txt += self.build_element_node_str(
+                    modifier,
+                    evm_info["mapping", contract.name],
+                    evm_info["cfg", contract.name],
+                )
 
         self.info(txt)
         res = self.generate_output(txt)