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

Erik python at lucidity.plus.com
Tue Dec 29 05:32:40 EST 2015 
Hi Nick,

On 29/12/15 02:46, Nick Coghlan wrote:
> 1. The interpreter's bytecode generation is inconsistent with the
> implementation of the eval loop

Essentially, this was my problem. I'd neglected to add the reference to 
TARGET_NEW_OP2 to Python/opcode_targets.h (so staring hard at the op 
generation and ceval implementation did not help me: they were both fine).

I'd forgotten adding the first op to that array, and section 24.8 of 
https://docs.python.org/devguide/compiler.html doesn't mention that file 
either. I will look at raising a docs bug on that.

> It's also the case that to rule out the bootstrapping cycle as a
> potential source of problems, you can try the following manual dance:
>
> 1. Revert to a clean checkout and rebuild
> 2. Apply the eval loop changes, and rebuild
> 3. Apply the code generation changes, and rebuild

Thanks - this is useful to know. It's a bit chicken-and-egg if one has 
introduced a bug which stops the build-time execution of the python 
auto-generation scripts from executing correctly :)

E.
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