linker `rust-lld` not found

[greyltc]

I'm building on Arch Linux (x86_64) and I've built rust 1.49.0 with the following config.toml:

[build]
target = ["x86_64-unknown-linux-gnu", "wasm32-unknown-unknown"]
extended = true
docs = false
sanitizers = false
profiler = true
vendor = true

[rust]
channel = "stable"
rpath = false

[install]
prefix = "/usr"

[target.x86_64-unknown-linux-gnu]
llvm-config = "/usr/bin/llvm-config"

[target.wasm32-unknown-unknown]
llvm-config = "/usr/bin/llvm-config"
wasi-root = "/usr/lib/wasi"
profiler = false

I've actually tried building it twice. Once with the above and once without the llvm-config lines, both give me the same problem.

I'm using the latest wasm-pack, 0.9.1.

When I cd into https://github.com/rustwasm/wasm-bindgen/tree/master/examples/without-a-bundler
and run wasm-pack build --target web:

$ wasm-pack build --target web
[INFO]: Checking for the Wasm target...
[INFO]: Compiling to Wasm...
   Compiling proc-macro2 v1.0.24
   Compiling unicode-xid v0.2.1
   Compiling wasm-bindgen-shared v0.2.69 (wasm-bindgen-0.2.69/crates/shared)
   Compiling log v0.4.11
   Compiling syn v1.0.57
   Compiling cfg-if v0.1.10
   Compiling lazy_static v1.4.0
   Compiling bumpalo v3.4.0
   Compiling wasm-bindgen v0.2.69 (wasm-bindgen-0.2.69)
   Compiling cfg-if v1.0.0
   Compiling quote v1.0.8
   Compiling wasm-bindgen-backend v0.2.69 (wasm-bindgen-0.2.69/crates/backend)
   Compiling wasm-bindgen-macro-support v0.2.69 (wasm-bindgen-0.2.69/crates/macro-support)
   Compiling wasm-bindgen-macro v0.2.69 (wasm-bindgen-0.2.69/crates/macro)
   Compiling js-sys v0.3.46 (wasm-bindgen-0.2.69/crates/js-sys)
   Compiling web-sys v0.3.46 (wasm-bindgen-0.2.69/crates/web-sys)
   Compiling without-a-bundler v0.1.0 (wasm-bindgen-0.2.69/examples/without-a-bundler)
error: linker `rust-lld` not found
  |
  = note: No such file or directory (os error 2)

error: aborting due to previous error

error: could not compile `without-a-bundler`

To learn more, run the command again with --verbose.
Error: Compiling your crate to WebAssembly failed
Caused by: failed to execute `cargo build`: exited with exit code: 101
  full command: "cargo" "build" "--lib" "--release" "--target" "wasm32-unknown-unknown"

Some person here thinks this is a problem with the rust compiler: drager/wasm-pack#754 (comment)

It seems like that's true, because this thread explains what the gentoo packagers did to their rust package work around this problem:
https://bugs.gentoo.org/715348
(tldr: sed -i '/linker:/ s/rust-lld/wasm-ld/' src/librustc_target/spec/wasm32_base.rs)

The only place I can find a file called rust-lld is rustc-1.49.0-src/build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/bin/rust-lld after I build, but that just seems like a build artifact that never gets installed anywhere. Am I missing something special that I have to do to get rust-lld deployed/installed properly? Have I done something wrong in my config.toml file or otherwise?

Note that
RUSTFLAGS="-C linker=lld" wasm-pack build --target web
works for me but
RUSTFLAGS="-C linker=wasm-ld" wasm-pack build --target web
fails with some error about something needing to be build with -fPIC and a warning that "creating shared libraries, with -shared, is not yet stable"
Needing to override RUSTFLAGS to fix a (broken?) default linker doesn't feel like an actual solution.

[Mark-Simulacrum]

I would expect you to need to add lld = true to [rust] block in config.toml.

[greyltc]

Thanks! I'll give this a go!

[greyltc]

That build failed after some time with:

-- Build files have been written to: /mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/build/x86_64-unknown-linux-gnu/lld/build
running: "cmake" "--build" "." "--target" "install" "--config" "Release" "--" "-j" "8"
[61/141] Building CXX object COFF/CMakeFiles/lldCOFF.dir/Writer.cpp.o
FAILED: COFF/CMakeFiles/lldCOFF.dir/Writer.cpp.o 
/usr/lib/ccache/bin/c++ -DGTEST_HAS_RTTI=0 -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ICOFF -I/mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/src/llvm-project/lld/COFF -I/mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/src/llvm-project/lld/include -Iinclude -ffunction-sections -fdata-sections -fPIC -m64 -march=x86-64 -mtune=generic -pipe -fno-plt -fPIC -fvisibility-inlines-hidden -Werror=date-time -w -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -fno-exceptions -fno-rtti -std=gnu++14 -MD -MT COFF/CMakeFiles/lldCOFF.dir/Writer.cpp.o -MF COFF/CMakeFiles/lldCOFF.dir/Writer.cpp.o.d -o COFF/CMakeFiles/lldCOFF.dir/Writer.cpp.o -c /mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/src/llvm-project/lld/COFF/Writer.cpp
/mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/src/llvm-project/lld/COFF/Writer.cpp: In member function ‘void {anonymous}::Writer::fixTlsAlignment()’:
/mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/src/llvm-project/lld/COFF/Writer.cpp:2030:13: error: ‘using coff_tls_directory64 = struct llvm::object::coff_tls_directory<llvm::support::detail::packed_endian_specific_integral<long int, llvm::support::little, 1> >’ {aka ‘struct llvm::object::coff_tls_directory<llvm::support::detail::packed_endian_specific_integral<long int, llvm::support::little, 1> >’} has no member named ‘setAlignment’; did you mean ‘getAlignment’?
 2030 |     tlsDir->setAlignment(tlsAlignment);
      |             ^~~~~~~~~~~~
      |             getAlignment
/mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/src/llvm-project/lld/COFF/Writer.cpp:2034:13: error: ‘using coff_tls_directory32 = struct llvm::object::coff_tls_directory<llvm::support::detail::packed_endian_specific_integral<int, llvm::support::little, 1> >’ {aka ‘struct llvm::object::coff_tls_directory<llvm::support::detail::packed_endian_specific_integral<int, llvm::support::little, 1> >’} has no member named ‘setAlignment’; did you mean ‘getAlignment’?
 2034 |     tlsDir->setAlignment(tlsAlignment);
      |             ^~~~~~~~~~~~
      |             getAlignment
[68/141] Building CXX object COFF/CMakeFiles/lldCOFF.dir/SymbolTable.cpp.o
ninja: build stopped: subcommand failed.
thread 'main' panicked at '
command did not execute successfully, got: exit code: 1

build script failed, must exit now', /mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/vendor/cmake/src/lib.rs:885:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
	finished in 24.215 seconds
failed to run: /mnt/scratch/git/rust-wasm/src/rustc-1.49.0-src/build/bootstrap/debug/bootstrap dist -j 8
Build completed unsuccessfully in 0:07:46
==> ERROR: A failure occurred in build().

I'll try again removing the llvm-config = "/usr/bin/llvm-config" lines from my config.toml

[greyltc]

Yep, lld = true in [rust] causes the install step to install /usr/lib/rustlib/x86_64-unknown-linux-gnu/bin/rust-lld which means my wasm linking now works out of the box, thanks!