Allow host functions to call Wasm functions

[Robbepop]

Closes #572

[paritytech-cicd-pr]

BENCHMARKS

	NATIVE			WASMTIME
BENCHMARK	MASTER	PR	DIFF	MASTER	PR	DIFF	WASMTIME OVERHEAD
execute/ bare_call_0	1.05ms	1.63ms	🔴 54.66%	1.02ms	1.26ms	🔴 23.91%	🟢 -22%
execute/ bare_call_0/typed	539.14µs	964.88µs	🔴 77.58%	462.54µs	696.41µs	🔴 50.60%	🟢 -28%
execute/ bare_call_1	1.05ms	1.66ms	🔴 57.41%	1.25ms	1.60ms	🔴 27.71%	🟢 -3%
execute/ bare_call_16	2.11ms	2.76ms	🔴 30.22%	4.89ms	4.81ms	🔴 -1.50%	🟡 74%
execute/ bare_call_16/typed	1.51ms	1.86ms	🔴 23.10%	2.05ms	2.36ms	🔴 14.74%	🟢 27%
execute/ bare_call_1/typed	610.89µs	1.11ms	🔴 79.56%	771.01µs	1.12ms	🔴 45.98%	🟢 1%
execute/ bare_call_4	1.20ms	1.81ms	🔴 50.90%	2.01ms	2.30ms	🔴 14.29%	🟢 27%
execute/ bare_call_4/typed	641.85µs	1.13ms	🔴 77.12%	865.13µs	1.19ms	🔴 37.31%	🟢 5%
execute/ br_table	630.29µs	1.09ms	🔴 72.94%	995.87µs	1.37ms	🔴 37.69%	🟢 26%
execute/ count_until	651.17µs	739.93µs	🔴 13.66%	2.17ms	2.16ms	⚪ -0.17%	🔴 192%
execute/ factorial_iterative	309.40µs	321.63µs	🔴 4.11%	919.15µs	909.27µs	🟢 -1.18%	🔴 183%
execute/ factorial_recursive	610.41µs	643.57µs	🔴 5.38%	1.33ms	1.88ms	🔴 42.40%	🔴 193%
execute/ fib_iterative	1.54ms	1.43ms	🟢 -7.29%	4.79ms	4.98ms	🔴 4.00%	🔴 247%
execute/ fib_recursive	5.75ms	5.72ms	⚪ -0.53%	12.21ms	12.04ms	🟢 -1.35%	🔴 110%
execute/ global_bump	955.29µs	1.04ms	🔴 8.91%	3.32ms	3.16ms	🟢 -4.86%	🔴 204%
execute/ global_const	801.34µs	831.08µs	⚪ 3.50%	2.49ms	2.48ms	⚪ -0.74%	🔴 198%
execute/ host_calls	28.92µs	28.57µs	⚪ -1.16%	42.42µs	44.01µs	🔴 3.83%	🟡 54%
execute/ memory_fill	1.30ms	1.39ms	🔴 6.70%	4.20ms	4.27ms	🔴 1.79%	🔴 206%
execute/ memory_sum	1.33ms	1.28ms	🟢 -3.87%	4.34ms	4.20ms	🟢 -3.45%	🔴 229%
execute/ memory_vec_add	2.74ms	2.78ms	🔴 1.24%	8.84ms	8.72ms	🟢 -1.54%	🔴 214%
execute/ recursive_is_even	1.13ms	1.11ms	🟢 -1.49%	2.20ms	2.25ms	🔴 2.20%	🔴 103%
execute/ recursive_ok	143.26µs	142.83µs	⚪ -0.41%	304.60µs	315.09µs	🔴 3.44%	🔴 121%
execute/ recursive_scan	178.83µs	180.26µs	⚪ 0.68%	390.02µs	419.47µs	🔴 7.50%	🔴 133%
execute/ recursive_trap	14.12µs	13.98µs	🟢 -1.19%	30.47µs	31.15µs	🔴 2.08%	🔴 123%
execute/ regex_redux	544.79µs	549.26µs	⚪ 0.78%	1.55ms	1.56ms	⚪ 0.35%	🔴 183%
execute/ rev_complement	522.17µs	518.09µs	⚪ -0.94%	1.55ms	1.58ms	🔴 2.09%	🔴 206%
execute/ tiny_keccak	369.79µs	375.07µs	🔴 1.37%	1.29ms	1.26ms	🟢 -2.10%	🔴 237%
execute/ trunc_f2i	920.76µs	911.64µs	⚪ -1.07%	2.64ms	2.62ms	⚪ -0.49%	🔴 188%
instantiate/ wasm_kernel	58.27µs	60.07µs	🔴 5.06%	90.72µs	72.50µs	🟢 -20.31%	🟢 21%
translate/ erc1155	206.56µs	209.08µs	🔴 1.56%	405.39µs	422.06µs	🔴 3.58%	🔴 102%
translate/ erc20	100.28µs	104.08µs	🔴 3.96%	198.89µs	207.51µs	🔴 4.51%	🟡 99%
translate/ erc721	144.87µs	148.03µs	🔴 2.26%	289.17µs	300.07µs	🔴 3.78%	🔴 103%
translate/ spidermonkey	0.00ns	0.00ns	⚪ -0.06%	0.00ns	0.00ns	🔴 4.31%	🟢 0%
translate/ wasm_kernel	3.77ms	3.86ms	🔴 2.19%	7.67ms	7.87ms	🔴 2.80%	🔴 104%

Link to pipeline

[codecov-commenter]

Codecov Report

Merging #590 (c453d2a) into master (f82ed77) will increase coverage by 0.06%.
The diff coverage is 86.30%.

@@            Coverage Diff             @@
##           master     #590      +/-   ##
==========================================
+ Coverage   80.70%   80.76%   +0.06%     
==========================================
  Files          79       80       +1     
  Lines        6364     6416      +52     
==========================================
+ Hits         5136     5182      +46     
- Misses       1228     1234       +6     

Impacted Files	Coverage Δ
crates/wasmi/src/engine/config.rs	65.51% <40.00%> (-5.32%)	⬇️
crates/wasmi/src/engine/mod.rs	85.21% <86.27%> (+1.68%)	⬆️
crates/wasmi/tests/e2e/v1/host_calls_wasm.rs	100.00% <100.00%> (ø)

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[Robbepop]

The PR is no longer in WIP phase and is ready to be tested.

One remaining thing left to do is to implement stack limits that are based on the offsets of parent call stacks to properly guard against requiring more stack space than has been preconfigured.
For example, with the current implementation it is possible to circumvent call and value space limitations set in StackLimits via Config by calling host and Wasm functions to reset the stacks in between.

When this issue is resolved this PR is good to go.

[Robbepop]

The PR is no longer in WIP phase and is ready to be tested.

One remaining thing left to do is to implement stack limits that are based on the offsets of parent call stacks to properly guard against requiring more stack space than has been preconfigured. For example, with the current implementation it is possible to circumvent call and value space limitations set in StackLimits via Config by calling host and Wasm functions to reset the stacks in between.

When this issue is resolved this PR is good to go.

Since this fix is non trivial and also not super important I decided to do that in another PR and merge this PR as is.