[Python-Dev] Is there a reference manual for Python bytecode?

[Erik]

Thanks for your help so far (I'm experimenting with the peephole 
optimizer - hence my question before as I was trying to work out how to 
know what the small integer hard-coded offsets should be when looking 
ahead in the bytecode).


I've successfully added a new opcode (generated by the optimizer and 
understood by the interpreter loop) but when adding a second I 
unexpectedly got the following error. I'm not doing anything different 
to what I did with the first opcode as far as I can tell (I have a 
TARGET(FOO) in ceval.c and have obviously defined the new opcode's value 
in opcode.h).


"""
./python -E -S -m sysconfig --generate-posix-vars ;\
	if test $? -ne 0 ; then \
		echo "generate-posix-vars failed" ; \
		rm -f ./pybuilddir.txt ; \
		exit 1 ; \
	fi
XXX lineno: 241, opcode: 1
Fatal Python error: Py_Initialize: can't import _frozen_importlib
Traceback (most recent call last):
   File "<frozen importlib._bootstrap>", line 698, in <module>
   File "<frozen importlib._bootstrap>", line 751, in BuiltinImporter
   File "<frozen importlib._bootstrap>", line 241, in _requires_builtin
SystemError: unknown opcode
Aborted (core dumped)
generate-posix-vars failed
make: *** [pybuilddir.txt] Error 1
"""

If I #ifdef out the code in peephole.c which generates my new (2nd) 
opcode, then the error does not occur. I tried a "make clean" first, but 
that didn't help (I realise that does not necessarily rule out a 
makefile dependency issue).

Does anyone know if this is a well-known symptom of forgetting to add 
something somewhere when adding a new opcode, or do I need to track it 
down some more myself? I did not have this problem when introducing my 
first new opcode.

Thanks, E.