Unable to build for wasm32-unknown-unknown on macOS with Apple Clang

[dignifiedquire]

I am trying to build ring for wasm32-unknown-unknown, and it works fine on my linux based machines (x68_64) but when trying to build on my mac (aarch64) it fails with the following error

ring on main is 📦 v0.17.5 via 🦀 v1.74.0
❯ cargo build --target wasm32-unknown-unknown --features wasm32_unknown_unknown_js
   Compiling proc-macro2 v1.0.69
   Compiling unicode-ident v1.0.12
   Compiling wasm-bindgen-shared v0.2.88
   Compiling log v0.4.20
   Compiling bumpalo v3.14.0
   Compiling once_cell v1.18.0
   Compiling wasm-bindgen v0.2.88
   Compiling libc v0.2.150
   Compiling cc v1.0.83
   Compiling ring v0.17.5 (/Users/dignifiedquire/opensource/ring)
   Compiling quote v1.0.33
   Compiling syn v2.0.39
The following warnings were emitted during compilation:

warning: error: unable to create target: 'No available targets are compatible with triple "wasm32-unknown-unknown"'
warning: 1 error generated.

error: failed to run custom build command for `ring v0.17.5 (/Users/dignifiedquire/opensource/ring)`

Caused by:
  process didn't exit successfully: `/Users/dignifiedquire/opensource/ring/target/debug/build/ring-4263c6975b978b5a/build-script-build` (exit status: 1)
  --- stdout
  cargo:rerun-if-env-changed=RING_PREGENERATE_ASM
  cargo:rustc-env=RING_CORE_PREFIX=ring_core_0_17_5_
  OPT_LEVEL = Some("0")
  TARGET = Some("wasm32-unknown-unknown")
  HOST = Some("aarch64-apple-darwin")
  cargo:rerun-if-env-changed=CC_wasm32-unknown-unknown
  CC_wasm32-unknown-unknown = None
  cargo:rerun-if-env-changed=CC_wasm32_unknown_unknown
  CC_wasm32_unknown_unknown = None
  cargo:rerun-if-env-changed=TARGET_CC
  TARGET_CC = None
  cargo:rerun-if-env-changed=CC
  CC = Some("clang")
  cargo:rerun-if-env-changed=CRATE_CC_NO_DEFAULTS
  CRATE_CC_NO_DEFAULTS = None
  DEBUG = Some("true")
  cargo:rerun-if-env-changed=CFLAGS_wasm32-unknown-unknown
  CFLAGS_wasm32-unknown-unknown = None
  cargo:rerun-if-env-changed=CFLAGS_wasm32_unknown_unknown
  CFLAGS_wasm32_unknown_unknown = None
  cargo:rerun-if-env-changed=TARGET_CFLAGS
  TARGET_CFLAGS = None
  cargo:rerun-if-env-changed=CFLAGS
  CFLAGS = None
  running: "clang" "-O0" "-ffunction-sections" "-fdata-sections" "-fPIC" "-g" "-fno-omit-frame-pointer" "--target=wasm32-unknown-unknown" "-I" "include" "-I" "/Users/dignifiedquire/opensource/ring/target/wasm32-unknown-unknown/debug/build/ring-f6842382147d2afa/out" "-Wall" "-Wextra" "-fvisibility=hidden" "-std=c1x" "-pedantic" "-Wall" "-Wextra" "-Wbad-function-cast" "-Wcast-align" "-Wcast-qual" "-Wconversion" "-Wenum-compare" "-Wfloat-equal" "-Wformat=2" "-Winline" "-Winvalid-pch" "-Wmissing-field-initializers" "-Wmissing-include-dirs" "-Wnested-externs" "-Wredundant-decls" "-Wshadow" "-Wsign-compare" "-Wsign-conversion" "-Wstrict-prototypes" "-Wundef" "-Wuninitialized" "-Wwrite-strings" "-g3" "-nostdlibinc" "-DRING_CORE_NOSTDLIBINC=1" "-Werror" "-o" "/Users/dignifiedquire/opensource/ring/target/wasm32-unknown-unknown/debug/build/ring-f6842382147d2afa/out/crypto/curve25519/curve25519.o" "-c" "crypto/curve25519/curve25519.c"
  cargo:warning=error: unable to create target: 'No available targets are compatible with triple "wasm32-unknown-unknown"'

  cargo:warning=1 error generated.

  exit status: 1

  --- stderr

  error occurred: Command "clang" "-O0" "-ffunction-sections" "-fdata-sections" "-fPIC" "-g" "-fno-omit-frame-pointer" "--target=wasm32-unknown-unknown" "-I" "include" "-I" "/Users/dignifiedquire/opensource/ring/target/wasm32-unknown-unknown/debug/build/ring-f6842382147d2afa/out" "-Wall" "-Wextra" "-fvisibility=hidden" "-std=c1x" "-pedantic" "-Wall" "-Wextra" "-Wbad-function-cast" "-Wcast-align" "-Wcast-qual" "-Wconversion" "-Wenum-compare" "-Wfloat-equal" "-Wformat=2" "-Winline" "-Winvalid-pch" "-Wmissing-field-initializers" "-Wmissing-include-dirs" "-Wnested-externs" "-Wredundant-decls" "-Wshadow" "-Wsign-compare" "-Wsign-conversion" "-Wstrict-prototypes" "-Wundef" "-Wuninitialized" "-Wwrite-strings" "-g3" "-nostdlibinc" "-DRING_CORE_NOSTDLIBINC=1" "-Werror" "-o" "/Users/dignifiedquire/opensource/ring/target/wasm32-unknown-unknown/debug/build/ring-f6842382147d2afa/out/crypto/curve25519/curve25519.o" "-c" "crypto/curve25519/curve25519.c" with args "clang" did not execute successfully (status code exit status: 1).

warning: build failed, waiting for other jobs to finish...

I tried to find sth in the issues, but was unable to find any hints of what I am doing wrong/not setting. Appreciate any help!

[briansmith]

Apple Clang is a fork of Clang that is specialized to Apple's wishes. It doesn't support wasm32-unknown-unknown, at least when I tried. You need to download and use llvm.org Clang instead.

[simbleau]

For anyone who has had this issue and is arriving here in the future, here's what you need to do:

Install Homebrew (if you haven't already):

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

Install LLVM Clang:

brew install llvm

Verify the installation:

llvm-config --version

Export the correct PATH:

echo 'export PATH="/opt/homebrew/opt/llvm/bin:$PATH"' >> ~/.zshrc