Enable use of global secp256k1 context

[davxy]

Context creation is expensive.

Use the preallocated context that ships with the library.

Follows from the work done for this paritytech/substrate#10798

[paritytech-cicd-pr]

🦑 📈 ink! Example Contracts ‒ Changes Report 📉 🦑

These are the results when building the examples/* contracts from this branch with cargo-contract 0.17.0-1d1dc59 and comparing them to ink! master:

	Δ Optimized Size	Δ Used Gas	Total Optimized Size	Total Used Gas
accumulator			1.44 K
adder			2.94 K
contract-terminate			1.31 K	215_704
contract-transfer	+0.57 K		8.55 K	15_704
delegator			7.63 K	51_343
dns			10.20 K	47_112
erc1155	+0.82 K		28.32 K	94_224
erc20			9.80 K	47_112
erc721			13.70 K	125_632
flipper			1.76 K	15_704
incrementer			1.64 K	15_704
multisig	-0.02 K		26.76 K	103_580
proxy	+0.06 K	+61	3.87 K	32_304
rand-extension			5.12 K	15_704
subber			2.96 K
trait-erc20			10.10 K	47_112
trait-flipper			1.53 K	15_704
trait-incrementer			1.62 K	31_408

Link to the run | Last update: Thu Feb 10 18:44:07 CET 2022

[codecov-commenter]

Codecov Report

Merging #1123 (f34b28d) into master (1188ee7) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1123      +/-   ##
==========================================
- Coverage   78.80%   78.78%   -0.02%     
==========================================
  Files         252      252              
  Lines        9397     9394       -3     
==========================================
- Hits         7405     7401       -4     
- Misses       1992     1993       +1     

Impacted Files	Coverage Δ
crates/engine/src/tests.rs	100.00% <ø> (ø)
crates/engine/src/ext.rs	72.22% <100.00%> (-0.20%)	⬇️
...tes/env/src/engine/experimental_off_chain/impls.rs	53.70% <100.00%> (-0.43%)	⬇️
crates/env/src/engine/off_chain/impls.rs	41.88% <100.00%> (-0.50%)	⬇️
...ates/storage/src/collections/hashmap/fuzz_tests.rs	94.68% <0.00%> (-1.07%)	⬇️

---

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[xgreenx]

ink! doesn't use secp256k1 to recover, generate keys. So it doesn't use the context. Usage of the context will increase the size of the contracts. It is why that function was moved to contract-pallet.

Maybe I'm not right and it doesn't affect the size of the contract, could you check it, please?=)

[davxy]

ink! doesn't use secp256k1 to recover, generate keys. So it doesn't use the context. Usage of the context will increase the size of the contracts. It is why that function was moved to contract-pallet.

Maybe I'm not right and it doesn't affect the size of the contract, could you check it, please?=)

@xgreenx Ink! has already replaced libsecp256k1 with secp256k1 here #1052

If you check the changed files, this PR only introduces the usage of the global secp256k1 feature.

But maybe that is not what you mean and I misinterpreted your comment :-)

[xgreenx]

Ohh, okay, you only enabled that feature for tests. You didn't touch the code related to contracts.

[HCastano]

Looks fine, just one thing to check related to std features

[HCastano]

Not sure why there are contract size changes. I checked PR out and built the contracts locally and they're smaller than what the waterfall reports (and match master) 🤷‍♂️

Anyways, thanks!