Hi, For my registervm project (fork of CPython using register-based bytecode, instead of stack-based bytecode), I implemented a Instruction.use_stack() method which just checks if the stack is "used": read the stack, exchange values in the stack (like "ROT" instruction), push or pop a value.
Instruction.use_stack(): http://hg.python.org/sandbox/registervm/file/ff24dfecc27d/Lib/registervm.py#l546 The method uses a dummy heuristic, just because it was quick to implement it, and it's enough for my use case. To answer your question: yes, I would like a opcode_stack_effect() function. registervm has its own disassembler which creates objects, rather than just generating a text representation of the bytecode. I'm using objects because I rewrite most instructions and I need more information and functions: * disassembler (raw bytes => list of instructions) * assembler (list of instructions => raw bytes) * format an instruction (human readable assembler) * is_terminal(): last instruction of a block * is_cond_jump(): the instruction is a conditional jump? hesitate to move this disassembler to CPython directly. I'm not sure that it would be useful, its API is maybe too specific to my registervm project. * is_reg_used(), is_reg_replaced(), is_reg_modified(), etc.: checks on registers * etc. Would it be useful to have such high-level API in Python? Victor 2013/7/3 Larry Hastings <la...@hastings.org>: > > > I wrote my own assembler for Python bytecode called "Maynard". I had to > statically compute the stack effects for each bytecode instruction by hand; > what I did was copied and pasted opcode_stack_effect() (which is static) out > of Python/compile.c and into my own driver program, then I probed it with > test values to produce a table. I then coded up a function using that > table, but hand-calculating the value sometimes as there are some opcodes > whose stack effect varies based on the oparg. > > It sure would be nice if this information was simply available to the Python > interpreter; theoretically it can change between point releases. Would > anybody mind if I added it somewhere? I'd probably just expose > opcode_stack_effect to Python, then add all this other junk to the dis > module and make it available there. > > > /arry > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/victor.stinner%40gmail.com > _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
