Add Wasm build for MacOS

[bonomat]

This PR adds MacOS build to CI to ensure that the library also build on MacOS.

The library does not compile to wasm using the default clang setup on MacOS.
We are able to work around this by setting the environment variables CC and AR to use clang and llvm-ar provided by llvm.

//edit// outdated description below
Hi,

we depend on this library in one of our projects and fail to compile it to wasm on MacOS.
Do you have an idea what's going wrong?

I was able to reproduce it on CI (see below or here for more information here: https://github.com/bonomat/rust-secp256k1/pull/1/checks?check_run_id=1534192675):

    Compiling secp256k1 v0.19.0 (/Users/runner/work/rust-secp256k1/rust-secp256k1)
    Finished test [unoptimized + debuginfo] target(s) in 1.37s
     Running target/wasm32-unknown-unknown/debug/deps/secp256k1-3f31b356cd36a038.wasm
Set timeout to 20 seconds...
Executing bindgen...                              
internal/modules/cjs/loader.js:883
  throw err;
  ^

Error: Cannot find module 'env'
Require stack:
- /Users/runner/work/rust-secp256k1/rust-secp256k1/target/wasm32-unknown-unknown/wbg-tmp/wasm-bindgen-test.js
- /Users/runner/work/rust-secp256k1/rust-secp256k1/target/wasm32-unknown-unknown/wbg-tmp/run.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:880:15)
    at Function.Module._load (internal/modules/cjs/loader.js:725:27)
    at Module.require (internal/modules/cjs/loader.js:952:19)
    at require (internal/modules/cjs/helpers.js:88:18)
    at Object.<anonymous> (/Users/runner/work/rust-secp256k1/rust-secp256k1/target/wasm32-unknown-unknown/wbg-tmp/wasm-bindgen-test.js:3:18)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Module.require (internal/modules/cjs/loader.js:952:19) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    '/Users/runner/work/rust-secp256k1/rust-secp256k1/target/wasm32-unknown-unknown/wbg-tmp/wasm-bindgen-test.js',
    '/Users/runner/work/rust-secp256k1/rust-secp256k1/target/wasm32-unknown-unknown/wbg-tmp/run.js'
  ]
}
error: test failed, to rerun pass '--lib'
Error: Running Wasm tests with wasm-bindgen-test failed
Caused by: failed to execute `cargo test`: exited with exit code: 1
  full command: "cargo" "test" "--target" "wasm32-unknown-unknown"

[apoelstra]

Can you open up the offending file and see what it's trying to read from env?

My guess is that somehow something from libc has slipped into the library. Or perhaps clang is inserting something from libc.

[bonomat]

I used wasm2wat (https://webassembly.github.io/wabt/demo/wasm2wat/) and found these lines:

I'm not sure what to make from this.

 (import "env" "rustsecp256k1_v0_3_1_ecdsa_signature_parse_der" (func $rustsecp256k1_v0_3_1_ecdsa_signature_parse_der (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_ecdsa_signature_parse_compact" (func $rustsecp256k1_v0_3_1_ecdsa_signature_parse_compact (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_ecdsa_signature_parse_der_lax" (func $rustsecp256k1_v0_3_1_ecdsa_signature_parse_der_lax (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_ecdsa_signature_normalize" (func $rustsecp256k1_v0_3_1_ecdsa_signature_normalize (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_ecdsa_signature_serialize_der" (func $rustsecp256k1_v0_3_1_ecdsa_signature_serialize_der (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_ecdsa_signature_serialize_compact" (func $rustsecp256k1_v0_3_1_ecdsa_signature_serialize_compact (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_keypair_create" (func $rustsecp256k1_v0_3_1_keypair_create (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_keypair_xonly_tweak_add" (func $rustsecp256k1_v0_3_1_keypair_xonly_tweak_add (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_keypair_xonly_pub" (func $rustsecp256k1_v0_3_1_keypair_xonly_pub (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_xonly_pubkey_tweak_add" (func $rustsecp256k1_v0_3_1_xonly_pubkey_tweak_add (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_xonly_pubkey_from_pubkey" (func $rustsecp256k1_v0_3_1_xonly_pubkey_from_pubkey (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_xonly_pubkey_parse" (func $rustsecp256k1_v0_3_1_xonly_pubkey_parse (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_xonly_pubkey_serialize" (func $rustsecp256k1_v0_3_1_xonly_pubkey_serialize (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_ecdh" (func $rustsecp256k1_v0_3_1_ecdh (type $t18)))
  (import "env" "rustsecp256k1_v0_3_1_context_preallocated_create" (func $rustsecp256k1_v0_3_1_context_preallocated_create (type $t11)))
  (import "env" "rustsecp256k1_v0_3_1_schnorrsig_sign" (func $rustsecp256k1_v0_3_1_schnorrsig_sign (type $t18)))
  (import "env" "rustsecp256k1_v0_3_1_schnorrsig_verify" (func $rustsecp256k1_v0_3_1_schnorrsig_verify (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_context_preallocated_size" (func $rustsecp256k1_v0_3_1_context_preallocated_size (type $t16)))
  (import "env" "rustsecp256k1_v0_3_1_context_randomize" (func $rustsecp256k1_v0_3_1_context_randomize (type $t11)))
  (import "env" "rustsecp256k1_v0_3_1_ecdsa_sign" (func $rustsecp256k1_v0_3_1_ecdsa_sign (type $t18)))
  (import "env" "rustsecp256k1_v0_3_1_ecdsa_verify" (func $rustsecp256k1_v0_3_1_ecdsa_verify (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_ec_seckey_verify" (func $rustsecp256k1_v0_3_1_ec_seckey_verify (type $t11)))
  (import "env" "rustsecp256k1_v0_3_1_ec_privkey_negate" (func $rustsecp256k1_v0_3_1_ec_privkey_negate (type $t11)))
  (import "env" "rustsecp256k1_v0_3_1_ec_seckey_tweak_add" (func $rustsecp256k1_v0_3_1_ec_seckey_tweak_add (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_ec_seckey_tweak_mul" (func $rustsecp256k1_v0_3_1_ec_seckey_tweak_mul (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_ec_pubkey_parse" (func $rustsecp256k1_v0_3_1_ec_pubkey_parse (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_ec_pubkey_serialize" (func $rustsecp256k1_v0_3_1_ec_pubkey_serialize (type $t15)))
  (import "env" "rustsecp256k1_v0_3_1_ec_pubkey_combine" (func $rustsecp256k1_v0_3_1_ec_pubkey_combine (type $t13)))
  (import "env" "rustsecp256k1_v0_3_1_ec_pubkey_create" (func $rustsecp256k1_v0_3_1_ec_pubkey_create (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_ec_pubkey_negate" (func $rustsecp256k1_v0_3_1_ec_pubkey_negate (type $t11)))
  (import "env" "rustsecp256k1_v0_3_1_ec_pubkey_tweak_add" (func $rustsecp256k1_v0_3_1_ec_pubkey_tweak_add (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_ec_pubkey_tweak_mul" (func $rustsecp256k1_v0_3_1_ec_pubkey_tweak_mul (type $t17)))
  (import "env" "rustsecp256k1_v0_3_1_context_preallocated_destroy" (func $rustsecp256k1_v0_3_1_context_preallocated_destroy (type $t4)))

[TheBlueMatt]

Error: Cannot find module 'env'

This doesn't sound like an issue in the library, more like a general node issue than a secp-specific one. I do wonder if @arik-so has seen anything similar, I believe he has.

[arik-so]

Yes, I have. Experimenting with various optimization settings in Cargo.toml might be able to fix it, see rustwasm/wasm-pack#743 (comment)

[bonomat]

Yes, I have. Experimenting with various optimization settings in Cargo.toml might be able to fix it, see rustwasm/wasm-pack#743 (comment)

I played around with various combinations but no luck so far. Did you have any success?

[rishflab]

MacOS build fixed: https://github.com/bonomat/rust-secp256k1/pull/2/commits/74effb7fae29726a11a43b39ae9b248b126c5498

The default clang installation provided in MacOS seems to be causing the issue. Fixed by installing clang using brew and using the new installation via env variables.

brew install llvm

CC=/usr/local/opt/llvm/bin/clang
AR=/usr/local/opt/llvm/bin/llvm-ar

before running

wasm-pack build
wasm-pack test --node

[bonomat]

Thanks @rishflab 👏👏. I've updated this branch with your proposed changes.