Source code for jawa.transforms

Transforms are simple Instruction modifiers that can be called on each
Instruction by the :func:`~jawa.attributes.code.CodeAttribute.disassemble`
from jawa.util.bytecode import Instruction, Operand, OperandTypes, opcode_table

[docs]def expand_constants(ins: Instruction, *, cf) -> Instruction: """Replace CONSTANT_INDEX operands with the literal Constant object from the constant pool. :param ins: Instruction to potentially modify. :param cf: The ClassFile instance used to resolve Constants. :return: Potentially modified instruction. """ for i, operand in enumerate(ins.operands): if not isinstance(operand, Operand): continue if operand.op_type == OperandTypes.CONSTANT_INDEX: ins.operands[i] = cf.constants[operand.value] return ins
[docs]def simple_swap(ins: Instruction) -> Instruction: """Replaces one instruction with another based on the transform rules in the bytecode definitions. This can help simplify your code as it reduces the overall number of instructions. For example, `aload_0` will become `aload 0`. :param ins: Instruction to potentially modify. :return: Potentially modified instruction. """ try: rule = ins.details['transform']['simple_swap'] except KeyError: return ins replacement_ins = opcode_table[rule['op']] return Instruction( replacement_ins['mnemonic'], replacement_ins['op'], [Operand( replacement_ins['operands'][i][1], r ) for i, r in enumerate(rule['operands'])], ins.pos )