The dis module supports the analysis of Python byte code by
disassembling it. Since there is no Python assembler, this module defines the Python assembly
language. The Python byte code which this module takes as an input is defined in the file Include/opcode.h and used by the compiler and the interpreter.
Example: Given the function myfunc:
the following command can be used to get the disassembly of myfunc():
2 0 LOAD_GLOBAL 0 (len)
3 LOAD_FAST 0 (alist)
6 CALL_FUNCTION 1
10 LOAD_CONST 0 (None)
(The ``2'' is a line number).
The dis module defines the following functions and constants:
- Disassemble the bytesource object. bytesource can denote either a
module, a class, a method, a function, or a code object. For a module, it disassembles all
functions. For a class, it disassembles all methods. For a single code sequence, it prints
one line per byte code instruction. If no object is provided, it disassembles the last
- Disassembles the top-of-stack function of a traceback, using the last traceback if none
was passed. The instruction causing the exception is indicated.
- Disassembles a code object, indicating the last instruction if lasti was
provided. The output is divided in the following columns:
- the line number, for the first instruction of each line
- the current instruction, indicated as "-
- a labelled instruction, indicated with ">
- the address of the instruction,
- the operation code name,
- operation parameters, and
- interpretation of the parameters in parentheses.
The parameter interpretation recognizes local and global variable names, constant
values, branch targets, and compare operators.
- A synonym for disassemble. It is more convenient to type, and kept for compatibility
with earlier Python releases.
- Sequence of operation names, indexable using the byte code.
- Sequence of all compare operation names.
- Sequence of byte codes that have a constant parameter.
- Sequence of byte codes that access a free variable.
- Sequence of byte codes that access an attribute by name.
- Sequence of byte codes that have a relative jump target.
- Sequence of byte codes that have an absolute jump target.
- Sequence of byte codes that access a local variable.
- Sequence of byte codes of Boolean operations.