Build with LLVM and musl

flake.nix

@@ -93,13 +93,20 @@
     };
 
     overlays = load ./overlay "overlay";
-    legacyPackages = eachSystem (system: platform:
+    legacyPackages = eachSystem (system: platform: let
-      import nixpkgs {
+      pkgs = import nixpkgs {
-        localSystem = builtins.currentSystem or platform;
+        localSystem = builtins.currentSystem or system;
         crossSystem = platform;
         overlays = [ self.overlays.default ];
         config.allowUnsupportedSystem = true;
-      });
+      };
+    in pkgs // {
+      config = pkgs.config // {
+        replaceStdenv = { pkgs }: self.lib.stdenv pkgs pkgs.stdenv;
+        replaceCrossStdenv = { buildPackages, baseStdenv }:
+          self.lib.stdenv self.legacyPackages.${system} baseStdenv;
+      };
+    });
 
     packages = eachSystem (system: platform:
       let pkgs = self.legacyPackages.${system};
@@ -120,6 +127,13 @@
           targetHost = config.networking.fqdnOrHostName;
           targetUser = null;
         };
+
+        nixpkgs = let
+          platform = self.lib.platforms.x86_64-linux;
+        in {
+          buildPlatform = builtins.currentSystem or platform.system;
+          hostPlatform = platform;
+        };
       };
     };
 

lib/platforms.nix

@@ -4,13 +4,25 @@ let inherit (nixpkgs) lib;
 in lib.mapAttrs (system: platform: lib.systems.elaborate platform) {
   "x86_64-linux" = {
     system = "x86_64-linux";
+    config = "x86_64-unknown-linux-musl";
+    useLLVM = true;
+    linker = "lld";
+    gcc.arch = "x86-64-v3";
   };
 
   "aarch64-linux" = {
     system = "aarch64-linux";
+    config = "aarch64-unknown-linux-musl";
+    useLLVM = true;
+    linker = "lld";
+    gcc.arch = "armv8-a";
   };
 
   "riscv64-linux" = {
     system = "riscv64-linux";
+    config = "riscv64-unknown-linux-musl";
+    useLLVM = true;
+    linker = "lld";
+    gcc.arch = "rv64imacfd";
   };
 }

lib/stdenv.nix

@@ -0,0 +1,42 @@
+{ ... }: pkgs: stdenv:
+
+let
+  inherit (lib) optionalAttrs optionals toList;
+  inherit (pkgs) lib;
+  inherit (stdenv) targetPlatform;
+in pkgs.addAttrsToDerivation (prevAttrs: let
+  overrideAlloc = prevAttrs.overrideAlloc or true;
+
+  inputs = optionals overrideAlloc [ pkgs.mimalloc ];
+
+  cflags = [ "-pipe" ];
+  ldflags = [
+    "-O2"
+    "--hash-style=gnu"
+  ] ++ optionals overrideAlloc [ "-lmimalloc" ];
+
+  rustflags = [
+    "-C" "opt-level=2"
+    "-C" "linker-flavor=ld.lld"
+    "-C" "lto"
+    "-C" "linker-plugin-lto"
+    "-C" "link-arg=--icf=safe"
+    "-C" "link-arg=--lto-O2"
+  ] ++ optionals (targetPlatform.isx86_64 && targetPlatform ? gcc.arch) [
+    "-C" "target-cpu=${targetPlatform.gcc.arch}"
+  ] ++ (map (flag: [ "-C" "link-arg=${flag}" ]) ldflags |> lib.flatten);
+in {
+  buildInputs = prevAttrs.buildInputs or [ ] ++ inputs;
+
+  env = prevAttrs.env or { } // optionalAttrs (!prevAttrs ? NIX_CFLAGS_COMPILE) {
+    NIX_CFLAGS_COMPILE = toList prevAttrs.env.NIX_CFLAGS_COMPILE or [ ] ++ cflags |> toString;
+  } // optionalAttrs (prevAttrs ? env.NIX_LDFLAGS) {
+    NIX_LDFLAGS = toList prevAttrs.NIX_LDFLAGS or [ ] ++ ldflags |> toString;
+  };
+
+  NIX_RUSTFLAGS = prevAttrs.NIX_RUSTFLAGS or [ ] ++ rustflags;
+} // optionalAttrs (prevAttrs ? NIX_CFLAGS_COMPILE) {
+  NIX_CFLAGS_COMPILE = toList prevAttrs.NIX_CFLAGS_COMPILE or [ ] ++ cflags;
+} // optionalAttrs (!prevAttrs ? env.NIX_LDFLAGS) {
+  NIX_LDFLAGS = toList prevAttrs.NIX_LDFLAGS or [ ] ++ ldflags;
+}) stdenv

nixos/module/default.nix

@@ -11,6 +11,7 @@
     iosched
     kernel
     locale-en_EU
+    musl
     network
     nix
     openssh

nixos/module/musl.nix

@@ -0,0 +1,7 @@
+{ ...}: { modulesPath, ... }: {
+  disabledModules = [
+    (modulesPath + "/config/ldso.nix")
+    (modulesPath + "/programs/nix-ld.nix")
+    (modulesPath + "/config/stub-ld.nix")
+  ];
+}

overlay/fixes.nix

@@ -4,6 +4,14 @@ let
   inherit (lib) toList;
   inherit (prev.stdenv) hostPlatform;
 in {
+  netbsd = prev.netbsd.overrideScope (final: prev: {
+    compatIfNeeded = [ final.compat ];
+
+    compat = prev.compat.overrideAttrs (prevAttrs: {
+      makeFlags = prevAttrs.makeFlags ++ [ "OBJCOPY=:" ];
+    });
+  });
+
   numactl = prev.numactl.overrideAttrs (prevAttrs: {
     patches = prevAttrs.patches or [ ] ++ [
       (final.fetchpatch {
@@ -13,19 +21,21 @@ in {
     ];
   });
 
+  python3 = prev.python3.overrideAttrs (prevAttrs: {
+    postFixup = let
+      lib = "$out/lib/${prevAttrs.passthru.libPrefix}";
+      prefix = "_sysconfigdata__linux_";
+      suffix = "${hostPlatform.parsed.cpu.name}-${hostPlatform.libc}";
+    in prevAttrs.postFixup + ''
+      test -e "${lib}/${prefix}${suffix}.py" \
+        || ln -s "${lib}/${prefix}"{,"${suffix}"}.py
+    '';
+  });
+
   redis = prev.redis.overrideAttrs {
     doCheck = false;
   };
 
-  python312 = prev.python312.override {
-    packageOverrides = final: prev: {
-      pywebview = prev.pywebview.overrideAttrs ({
-        doCheck = false;
-        doInstallCheck = false;
-      });
-    };
-  };
-
   sioyek = prev.sioyek.overrideAttrs (prevAttrs: {
     env = prevAttrs.env or { } // {
       NIX_CFLAGS_COMPILE = toList prevAttrs.env.NIX_CFLAGS_COMPILE or [ ]
@@ -33,6 +43,14 @@ in {
     };
   });
 
+  time = prev.time.overrideAttrs (prevAttrs: {
+    env = prevAttrs.env or { } // {
+      CFLAGS = toList prevAttrs.env.CFLAGS or [ ] ++ [
+        "-Wno-error=implicit-function-declaration"
+      ] |> toString;
+    };
+  });
+
   zeromq = prev.zeromq.overrideAttrs (prevAttrs: {
     postPatch = prevAttrs.postPatch or "" + ''
       substituteInPlace CMakeLists.txt \

overlay/mimalloc.nix

@@ -4,6 +4,7 @@ let
   inherit (nixpkgs) lib;
 in {
   mimalloc = (prev.mimalloc.overrideAttrs (prevAttrs: {
+    overrideAlloc = false;
     postPatch = prevAttrs.postPatch or "" + ''
       sed -E -i \
         -e 's/(\{ )1(, UNINIT, MI_OPTION_LEGACY\(purge_decommits,reset_decommits\) \})/\10\2/' \
@@ -33,10 +34,6 @@ in {
 
   fractal = prev.fractal.overrideAttrs (prevAttrs: {
     nativeBuildInputs = prevAttrs.nativeBuildInputs or [ ] ++ [ final.makeBinaryWrapper ];
-    buildInputs = prevAttrs.buildInputs or [ ] ++ [ final.mimalloc ];
-
-    NIX_RUSTFLAGS = lib.toList prevAttrs.NIX_RUSTFLAGS or [ ] ++ [ "-C" "link-arg=-lmimalloc" ];
-    
     postInstall = prevAttrs.postInstall or "" + ''
       wrapProgram "$out/bin/fractal" \
         --set MIMALLOC_RESERVE_HUGE_OS_PAGES 1
@@ -47,47 +44,8 @@ in {
     mpv = final.mpv-unwrapped;
     extraMakeWrapperArgs = [ "--set" "MIMALLOC_RESERVE_HUGE_OS_PAGES" "1" ];
   };
-} // lib.genAttrs [
-  "bat"
-  "bottom"
-  "cryptsetup"
-  "dbus-broker"
-  "erlang"
-  "fd"
-  "firefox-unwrapped"
-  "fuzzel"
-  "helix"
-  "kitty"
-  "mako"
-  "mpv-unwrapped"
-  "niri"
-  "nix"
-  "nushell"
-  "openssh"
-  "pipewire"
-  "pueue"
-  "ripgrep"
-  "sd"
-  "sioyek"
-  "sudo-rs"
-  "systemd"
-  "swayidle"
-  "swaylock"
-  "swaylock-effects"
-  "thunderbird-unwrapped"
-  "uutils-coreutils"
-  "uutils-coreutils-noprefix"
-  "waybar"
-  "wirepluber"
-  "xdg-desktop-portal-gnome"
-  "xdg-desktop-portal-gtk"
-] (pkg: prev.${pkg}.overrideAttrs (prevAttrs: {
-  buildInputs = prevAttrs.buildInputs or [ ] ++ [ final.mimalloc ];
-  env = prevAttrs.env or { } // lib.optionalAttrs (prevAttrs ? env.NIX_LDFLAGS) {
-    NIX_LDFLAGS = toString (lib.toList prevAttrs.env.NIX_LDFLAGS or [ ] ++ [ "-lmimalloc" ]);
-  };
 
-  NIX_RUSTFLAGS = lib.toList prevAttrs.NIX_RUSTFLAGS or [ ] ++ [ "-C" "link-arg=-lmimalloc" ];
+  perl = prev.perl.overrideAttrs {
-} // lib.optionalAttrs (!prevAttrs ? env.NIX_LDFLAGS) {
+    overrideAlloc = false;
-  NIX_LDFLAGS = lib.toList prevAttrs.NIX_LDFLAGS or [ ] ++ [ "-lmimalloc" ];
+  };
-}))
+}