feat: make Module::imports be pub

[yjhmelody]

If we want to create stub function, we must need to know the imports info.

I think substrate also need this method to do prepare_import like wasmtime.

[Robbepop]

LGTM Also in Wasmtime this exact same API is also public.

[Robbepop]

This PR is missing re-exporting the type ModuleImportsIter as public at the lib.rs. Should be a single line addition.

[paritytech-cicd-pr]

BENCHMARKS

	NATIVE			WASMTIME
BENCHMARK	MASTER	PR	DIFF	MASTER	PR	DIFF	WASMTIME OVERHEAD
execute/ bare_call_0	1.01ms	1.01ms	⚪ 0.05%	991.51µs	960.61µs	🔴 -2.74%	🟢 -5%
execute/ bare_call_0/typed	525.57µs	525.40µs	⚪ -0.07%	447.57µs	455.53µs	🔴 1.84%	🟢 -13%
execute/ bare_call_1	1.05ms	1.05ms	🟢 -0.35%	1.22ms	1.18ms	🔴 -3.27%	🟢 13%
execute/ bare_call_16	2.15ms	2.11ms	🟢 -2.11%	4.73ms	4.70ms	🔴 -1.02%	🔴 122%
execute/ bare_call_16/typed	1.50ms	1.50ms	⚪ -0.11%	2.34ms	2.51ms	🔴 7.08%	🟡 67%
execute/ bare_call_1/typed	607.98µs	607.96µs	⚪ -0.02%	736.56µs	738.81µs	⚪ 0.38%	🟢 22%
execute/ bare_call_4	1.19ms	1.24ms	🔴 3.76%	1.96ms	1.94ms	🔴 -0.96%	🟡 56%
execute/ bare_call_4/typed	619.03µs	630.79µs	🔴 1.93%	926.20µs	964.42µs	🔴 5.29%	🟡 53%
execute/ br_table	620.40µs	620.44µs	⚪ 0.00%	945.85µs	946.09µs	⚪ -0.09%	🟡 52%
execute/ count_until	710.50µs	711.06µs	⚪ 0.02%	2.19ms	2.18ms	⚪ -0.03%	🔴 207%
execute/ factorial_iterative	369.97µs	304.95µs	🟢 -17.28%	867.48µs	864.36µs	⚪ -0.19%	🔴 183%
execute/ factorial_recursive	604.79µs	609.61µs	⚪ 0.80%	1.30ms	1.28ms	⚪ -1.09%	🔴 111%
execute/ fib_iterative	1.49ms	1.43ms	🟢 -3.90%	4.62ms	4.61ms	⚪ -0.01%	🔴 222%
execute/ fib_recursive	5.75ms	6.04ms	🔴 5.98%	11.90ms	11.78ms	⚪ -1.09%	🟡 95%
execute/ global_bump	1.01ms	1.01ms	⚪ -0.01%	3.14ms	3.13ms	⚪ -0.18%	🔴 211%
execute/ global_const	802.72µs	716.49µs	🟢 -10.75%	2.59ms	2.48ms	🟢 -3.96%	🔴 246%
execute/ host_calls	29.95µs	29.01µs	🟢 -3.59%	41.77µs	41.08µs	🟢 -1.44%	🟢 42%
execute/ memory_fill	1.33ms	1.30ms	🟢 -2.15%	4.18ms	4.23ms	🔴 1.50%	🔴 225%
execute/ memory_sum	1.34ms	1.30ms	🟢 -3.14%	4.23ms	4.24ms	⚪ 0.12%	🔴 226%
execute/ memory_vec_add	2.68ms	2.58ms	🟢 -3.54%	8.46ms	8.50ms	⚪ 0.31%	🔴 230%
execute/ recursive_is_even	1.09ms	1.09ms	⚪ -0.29%	2.10ms	2.10ms	⚪ -0.13%	🟡 92%
execute/ recursive_ok	142.26µs	146.58µs	🔴 3.16%	298.39µs	298.72µs	⚪ 0.04%	🔴 104%
execute/ recursive_scan	178.34µs	178.24µs	⚪ -0.19%	381.61µs	382.62µs	⚪ 0.36%	🔴 115%
execute/ recursive_trap	13.92µs	13.94µs	⚪ 0.22%	30.01µs	30.03µs	⚪ 0.05%	🔴 115%
execute/ regex_redux	544.46µs	549.70µs	⚪ 1.01%	1.50ms	1.50ms	⚪ -0.08%	🔴 173%
execute/ rev_complement	507.95µs	499.95µs	🟢 -1.59%	1.49ms	1.49ms	⚪ 0.13%	🔴 198%
execute/ tiny_keccak	371.37µs	360.99µs	🟢 -3.01%	1.21ms	1.20ms	⚪ -0.25%	🔴 234%
execute/ trunc_f2i	916.85µs	911.09µs	⚪ -0.58%	2.52ms	2.51ms	⚪ -0.06%	🔴 176%
instantiate/ wasm_kernel	61.68µs	61.52µs	⚪ 0.38%	75.01µs	95.69µs	🔴 27.08%	🟡 56%
translate/ erc1155	205.57µs	207.87µs	⚪ 1.15%	407.18µs	408.46µs	⚪ 0.17%	🟡 96%
translate/ erc20	102.20µs	101.95µs	⚪ -0.14%	199.34µs	201.28µs	⚪ 0.94%	🟡 97%
translate/ erc721	145.82µs	146.04µs	⚪ 0.29%	290.25µs	289.22µs	⚪ -0.68%	🟡 98%
translate/ spidermonkey	0.00ns	0.00ns	⚪ -0.49%	0.00ns	0.00ns	⚪ -0.04%	🟢 0%
translate/ wasm_kernel	3.76ms	3.74ms	⚪ -0.43%	7.71ms	7.60ms	⚪ -1.04%	🔴 103%

Link to pipeline

[yjhmelody]

@Robbepop Hi, I will export it later.
But I have another point to mention, which is the same as the purpose of this PR. At present, Func::wrap does not support params in vec style now, which is different from wasmtime, will make it more troublesome to support feature such likeallow_miss_host_function.

[Robbepop]

I will create a PR to fix the clippy warnings, then you need to merge it so that we can finally merge your PR.

[Robbepop]

Changes I'd like to see before we merge:

Since ModuleImport is going to be pub now we should clean up its API, too.
We should make its new constructor as well as its name method pub(crate). This way we can also remove ModuleImportName from the public re-exports and shrink the wasmi API surface again. The field and module method getters should be sufficient.

[codecov-commenter]

Codecov Report

Merging #573 (8c5e2e6) into master (d9f5724) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #573   +/-   ##
=======================================
  Coverage   80.04%   80.04%           
=======================================
  Files          78       78           
  Lines        6323     6323           
=======================================
  Hits         5061     5061           
  Misses       1262     1262           

Impacted Files	Coverage Δ
crates/wasmi/src/module/mod.rs	85.08% <100.00%> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[yjhmelody]

Ok. I'm updating it.

[Robbepop]

@Robbepop Hi, I will export it later. But I have another point to mention, which is the same as the purpose of this PR. At present, Func::wrap does not support params in vec style now, which is different from wasmtime, will make it more troublesome to support feature such likeallow_miss_host_function.

I don't understand what you mean by this? What are "params in vec style" for Func::wrap? What is the allow_miss_host_function feature about exactly? Please elaborate!

This might be better done in a separate PR if at all.

[yjhmelody]

@Robbepop Hi, I will export it later. But I have another point to mention, which is the same as the purpose of this PR. At present, Func::wrap does not support params in vec style now, which is different from wasmtime, will make it more troublesome to support feature such likeallow_miss_host_function.

I don't understand what you mean by this? What are "params in vec style" for Func::wrap? What is the allow_miss_host_function feature about exactly? Please elaborate!

This might be better done in a separate PR if at all.

Ok.
Sorry, I thought that you would have to deal with related upgrades of the substrate in the future, and the implementation may be similar to wasmtime.
https://github.com/paritytech/substrate/blob/8016da9ddf1c10a5a74cc5a273905cfeb60ed82c/client/executor/wasmtime/src/imports.rs#L69-L68

Yes, I'll try it first and then make a new PR

[yjhmelody]

@Robbepop I do not know how to fix it:

342 |     /// An imported [`Global`].
    |                       ^^^^^^ this item is private
    |
    = note: `-D rustdoc::private-intra-doc-links` implied by `-D warnings`

I think it's not private.

[Robbepop]

@Robbepop I do not know how to fix it:

342 |     /// An imported [`Global`].
    |                       ^^^^^^ this item is private
    |
    = note: `-D rustdoc::private-intra-doc-links` implied by `-D warnings`

I think it's not private.

You should be able to fix it by adding the following two lines of doc comments:

///
/// [`Global`]: [`crate::Global`]