epic: State accesses

[ClementWalter]

Why

In the context of Kakarot, we used DictAccess to store accesses to the EVM state. For each new context, we needed to create a whole new dict (new segment, new dict manager). This is highly inefficient as illustrated in the first tx of block

What

Stop to copy segments. We only need to make sure that the values returned in context are

• consistent with a DictAccess => regular dict squashing
• consistent with the previous (main) state => the prev values of this small segments needs to be consistent with the values from the main segment.

How

When creating a new context

• create a new segment
• at the end of the context
  • if it reverts, squash and append all the prev keys to the main dict segment
  • if it succeeds, memcpy to the main segment OR squash and append memcpy the squashed dict