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Add an option to make disassembly more forgiving #19

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Add an option to make disassembly more forgiving #19

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25ad20d
Add an option to make disassembly more forgiving
feliam Sep 29, 2018
fe8a8b8
Forgot import
feliam Sep 29, 2018
9f737ff
Bugfix.. choose INVALID when undef
feliam Oct 1, 2018
012c64f
Merge branch 'master' into dev-silent
feliam Oct 19, 2018
e496ab6
merge
feliam Oct 22, 2018
9879473
Merge branch 'master' into dev-silent
feliam Mar 23, 2020
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27 changes: 21 additions & 6 deletions pyevmasm/evmasm.py
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
from binascii import hexlify, unhexlify
from builtins import map, next, range, object
from future.builtins import next, bytes
from copy imports copy

"""
Example use::
Expand Down Expand Up @@ -596,13 +597,15 @@ def assemble_all(asmcode, pc=0):
pc += instr.size


def disassemble_one(bytecode, pc=0):
def disassemble_one(bytecode, pc=0, silent=False):
""" Disassemble a single instruction from a bytecode

:param bytecode: the bytecode stream
:type bytecode: str | bytes | bytearray | iterator
:param pc: program counter of the instruction(optional)
:type pc: int
:param silent: if True disassemble unrecognized instructions as INVALID or incomplete intruction operands as zero
:type silent: bool
:return: an Instruction object
:rtype: Instruction

Expand All @@ -624,22 +627,32 @@ def disassemble_one(bytecode, pc=0):

assert isinstance(opcode, int)

instruction = instruction_table[opcode]

if silent:
if opcode not in instruction_table:
instruction = copy(instruction_table[opcode])
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Should this just get instruction_table[0xfe] for INVALID? Also is there something in the yellow paper that describes the behavior when an unimplemented instruction is run? Just want to make sure it's semantically the same as INVALID, but I don't see anything.

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Opps I ment to get 0xfe.

Unimplemented instruction is defined in the yellow (if I remember correctly) as the same as an INVALID. Only diff is that it may get redefined I guess ..

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    try:
        instruction = copy(instruction_table[opcode])
    except KeyError:
        if silent:
            instruction = copy(instruction_table[0xfe])
        else:
            raise

??

instruction = copy(instruction_table[opcode])
instruction.pc = pc

if silent:
from itertools import chain, repeat
bytecode = chain(bytecode, repeat(0))

if instruction.has_operand:
instruction.parse_operand(bytecode)

return instruction


def disassemble_all(bytecode, pc=0):
def disassemble_all(bytecode, pc=0, silent=False):
""" Disassemble all instructions in bytecode

:param bytecode: an evm bytecode (binary)
:type bytecode: str | bytes | bytearray | iterator
:param pc: program counter of the first instruction(optional)
:type pc: int
:param silent: if True disassemble unrecognized instructions as INVALID or incomplete intruction operands as zero
:type silent: bool
:return: An generator of Instruction objects
:rtype: list[Instruction]

Expand Down Expand Up @@ -670,19 +683,21 @@ def disassemble_all(bytecode, pc=0):

bytecode = iter(bytecode)
while True:
instr = disassemble_one(bytecode, pc=pc)
instr = disassemble_one(bytecode, pc=pc, silent=silent)
if not instr:
return
pc += instr.size
yield instr


def disassemble(bytecode, pc=0):
def disassemble(bytecode, pc=0, silent=False):
""" Disassemble an EVM bytecode

:param bytecode: binary representation of an evm bytecode
:type bytecode: str | bytes | bytearray
:param pc: program counter of the first instruction(optional)
:param silent: if True disassemble unrecognized instructions as INVALID or incomplete intruction operands as zero
:type silent: bool
:type pc: int
:return: the text representation of the assembler code

Expand All @@ -697,7 +712,7 @@ def disassemble(bytecode, pc=0):
PUSH2 0x100

"""
return '\n'.join(map(str, disassemble_all(bytecode, pc=pc)))
return '\n'.join(map(str, disassemble_all(bytecode, pc=pc, silent=silent)))


def assemble(asmcode, pc=0):
Expand Down