From 29f44a6f621aa642c7d596c68a3783507094a740 Mon Sep 17 00:00:00 2001 From: rajeevgopalakrishna Date: Fri, 7 Jun 2019 10:20:36 +0530 Subject: [PATCH] Adds comments and some more formatting changes --- slither/printers/summary/evm.py | 43 ++++++++++++++++++++++----------- 1 file changed, 29 insertions(+), 14 deletions(-) diff --git a/slither/printers/summary/evm.py b/slither/printers/summary/evm.py index 856c42b4f..2cdb12b3c 100644 --- a/slither/printers/summary/evm.py +++ b/slither/printers/summary/evm.py @@ -25,14 +25,14 @@ class PrinterEVM(AbstractPrinter): _filename(string) """ - source_to_pc_mapping = self._process_evm_cfg(self.slither) + evm_info = self._extract_evm_info(self.slither) for contract in self.slither.contracts_derived: print('Contract {}'.format(contract.name)) contract_file = self.slither.source_code[contract.source_mapping['filename_absolute']].encode('utf-8') contract_file_lines = open(contract.source_mapping['filename_absolute'],'r').readlines() - contract_pcs = source_to_pc_mapping['mapping', contract.name] - contract_cfg = source_to_pc_mapping['cfg', contract.name] + contract_cfg = evm_info['cfg', contract.name] + contract_pcs = evm_info['mapping', contract.name] for function in contract.functions: print(f'\tFunction {function.canonical_name}') for node in function.nodes: @@ -44,32 +44,44 @@ class PrinterEVM(AbstractPrinter): for pc in node_pcs: print('\t\t\t0x{:x}: {}'.format(int(pc), contract_cfg.get_instruction_at(pc))) for modifier in contract.modifiers: - print('\tModifier {}'.format(modifier.canonical_name)) + print(f'\tModifier {modifier.canonical_name}') for node in modifier.nodes: node_source_line = contract_file[0:node.source_mapping['start']].count("\n".encode("utf-8")) + 1 - print('\t\tSource line {:x}: {}'.format(node_source_line, contract_file_lines[node_source_line-1].rstrip())) + print('\t\tSource line {}: {}'.format(node_source_line, contract_file_lines[node_source_line-1].rstrip())) print('\t\tEVM Instructions:') node_pcs = contract_pcs.get(node_source_line, []) for pc in node_pcs: print('\t\t\t0x{:x}: {}'.format(int(pc), contract_cfg.get_instruction_at(pc))) - def _process_evm_cfg(self, slither): - source_to_pc_mapping = {} + def _extract_evm_info(self, slither): + ''' + Extract evm information for all derived contracts using evm_cfg_builder + + Returns: evm CFG and Solidity source to Program Counter (pc) mapping + ''' + evm_info = {} for contract in slither.contracts_derived: contract_bytecode_runtime = slither.crytic_compile.bytecode_runtime(contract.name) contract_srcmap_runtime = slither.crytic_compile.srcmap_runtime(contract.name) cfg = CFG(contract_bytecode_runtime) - source_to_pc_mapping['cfg', contract.name] = cfg - source_to_pc_mapping['mapping', contract.name] = self._generate_source_to_ins_mapping(cfg.instructions, + evm_info['cfg', contract.name] = cfg + evm_info['mapping', contract.name] = self._generate_source_to_evm_ins_mapping(cfg.instructions, contract_srcmap_runtime, slither, contract.source_mapping['filename_absolute']) - return(source_to_pc_mapping) + return(evm_info) - def _generate_source_to_ins_mapping(self, evm_instructions, srcmap_runtime, slither, filename): - source_to_pc_mapping = {} + def _generate_source_to_evm_ins_mapping(self, evm_instructions, srcmap_runtime, slither, filename): + ''' + Generate Solidity source to EVM instruction mapping using evm_cfg_builder:cfg.instructions and solc:srcmap_runtime + + Returns: Solidity source to EVM instruction mapping + ''' + source_to_evm_mapping = {} file_source = slither.source_code[filename].encode('utf-8') prev_mapping = [] for idx, mapping in enumerate(srcmap_runtime): + # Parse srcmap_runtime according to its format + # See https://solidity.readthedocs.io/en/v0.5.9/miscellaneous.html#source-mappings mapping_item = mapping.split(':') mapping_item += prev_mapping[len(mapping_item):] for i in range(len(mapping_item)): @@ -83,5 +95,8 @@ class PrinterEVM(AbstractPrinter): offset = int(offset) line_number = file_source[0:offset].count("\n".encode("utf-8")) + 1 prev_mapping = mapping_item - source_to_pc_mapping.setdefault(line_number, []).append(evm_instructions[idx].pc) - return(source_to_pc_mapping) + # Append evm instructions to the corresponding source line number + # Note: Some evm instructions in mapping are not necessarily in program execution order + # Note: The order depends on how solc creates the srcmap_runtime + source_to_evm_mapping.setdefault(line_number, []).append(evm_instructions[idx].pc) + return(source_to_evm_mapping)