Evaluate if wasm-opt embedded in stellar-cli is delivering enough value to keep

[leighmcculloch]

The stellar-cli embeds the wasm-opt tool and will run it on contracts after build to optimize them.

When we added the tool it was assumed maybe we need it, maybe it would be valuable. However in a lot of the past tests I did, Soroban contracts were already very well optimised because they don't pull in cruft from the Rust stdlib, which in early testing was where the biggest bloat arose from.

To my knowledge we've never done an assessment of real contracts to see if the size gains are actually meaningful. If the gains are not meaningful I will propose we remove the feature to reduce the surface area of what touches binaries between code and the wasm that runs on chain.

cc @brson

[brson]

The wasm-opt bindings have proved difficult for me to maintain - chasing upstream is very tedious and the bindings project is no longer funded. There is a PR against the repo that has been open for many months trying to upgrade, but my initial attempt to get it passing the test suite failed and I haven't returned to it.

[willemneal]

For what it's worth I use it often and see about 40-50% size reduction in contracts.

[kalepail]

I use it on every mainnet contract and see 20%-30% size reduction. Often +10k bytes shaved off

[earrietadev]

I use it with all my contracts, I've noticed that it's normally better the bigger the contract because with really simple contracts it doesn't reduce the size that much. But for big contracts it always reduce the size at minimum 15%

[towa-hi]

I have a very large contract and optimize reduces it from 44123b down to 37875b

[leighmcculloch]

Out of curiosity I tried running optimize on all the mainnet contracts, to see how much saving there was to gain, on the assumption that not all contracts have been optimized. The result is here:

• https://github.com/leighmcculloch/stellar-contract-wasms/blob/main/analysis/optimize.csv

[aolieman]

I'm seeing around 20% reduction if I don't count the meta / docstring bytes. With a couple of my user-facing contracts around half their total size is the meta literals.