[Constantinople] EIP 1283 SSTORE net metering

[holgerd77]

EIP 1283 SSTORE net metering without dirty maps (replaces EIP-1087)

Test Situation:
Open PR, affecting lots of tests
ethereum/tests#511
ethereum/tests#483

Implementation in the VM:
Mostly/all in the SSTORE opcode code.

[yann300]

I just looked at this one, what would be the best way to get an initial storage value, seems not really obvious. Is there some refactoring already happening for that?

[holgerd77]

No idea yet, we'll have to work this out together.

[holgerd77]

@yann300 Update: haven't looked deeper, but is stateManager.getContractStorage() already used in the opcode not already doing this?

[yann300]

it is but does it get the initial storage or the current storage?

[vpulim]

as @yann300 mentioned, stateManager.getContractStorage() only gets the current storage. I submitted a PR (#367) that sets runState.originalState to a copy of the stateManager trie so that it can later be used in the SSTORE opcode to read the original storage values. There may be a more efficient way to do this using the stateManager checkpoints but it will likely require non-trivial changes to stateManager

[holgerd77]

@vpulim For now this should work, better to have these updates ready in time for the dev tools to be used that start with complex StateManager refactorings.