ilyagr.bsky.social
just playing with tangled
nix: use mold linker on Linux
Summary: Pure QOL improvement, not that this was too awful as it stood. But this
ultimately makes all builds faster, effectively for free; on my Linux machine,
debug link time for jj-cli goes from 3s to 1s.
This was originally submitted as part of #1864, and backed out as part of #1982,
because the default `mold` package did not have the proper "wrapper script"
that allowed it to find the right external libraries. Using the `mold-wrapped`
package however fixes this.
On top of that, let's go ahead and make `mold` the default linker in the Nix
package/flake as well; this should improve the `nix build` speed since a lot of
tests need to be linked.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
+15
-2
+15
-2
flake.nix
+15
-2
flake.nix
···
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libiconv
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];
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+
# NOTE (aseipp): on Linux, go ahead and use mold by default to improve
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# link times a bit; mostly useful for debug build speed, but will help
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# over time if we ever get more dependencies, too
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useMoldLinker = pkgs.stdenv.isLinux;
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+
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# these are needed in both devShell and buildInputs
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linuxNativeDeps = with pkgs; lib.optionals stdenv.isLinux [
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mold-wrapped
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];
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+
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in
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{
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packages = {
···
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installShellFiles
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makeWrapper
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pkg-config
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-
];
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+
] ++ linuxNativeDeps;
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buildInputs = with pkgs; [
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openssl zstd libgit2 libssh2
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] ++ darwinDeps;
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ZSTD_SYS_USE_PKG_CONFIG = "1";
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LIBSSH2_SYS_USE_PKG_CONFIG = "1";
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+
RUSTFLAGS = pkgs.lib.optionalString useMoldLinker "-C link-arg=-fuse-ld=mold";
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NIX_JJ_GIT_HASH = self.rev or "";
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CARGO_INCREMENTAL = "0";
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···
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# For building the documentation website
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poetry
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-
] ++ darwinDeps;
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+
] ++ darwinDeps ++ linuxNativeDeps;
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shellHook = ''
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export RUST_BACKTRACE=1
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export ZSTD_SYS_USE_PKG_CONFIG=1
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export LIBSSH2_SYS_USE_PKG_CONFIG=1
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+
'' + pkgs.lib.optionalString useMoldLinker ''
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export RUSTFLAGS="-C link-arg=-fuse-ld=mold $RUSTFLAGS"
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'';
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};
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}));