From d95c1719aad43d9ec7c180db869b4134cda77617 Mon Sep 17 00:00:00 2001
From: Thomas Eizinger <thomas@eizinger.io>
Date: Wed, 24 Jul 2024 14:03:17 +1000
Subject: [PATCH] chore(nix): setup `mold` linker (#6009)

Also includes some minor tidy-up of the nix flake. `mold` is a much
faster linker and a drop-in replacement for GNU's `ld`.
---
 scripts/nix/flake.lock | 37 +++----------------------------------
 scripts/nix/flake.nix  | 17 +++++------------
 2 files changed, 8 insertions(+), 46 deletions(-)

diff --git a/scripts/nix/flake.lock b/scripts/nix/flake.lock
index 9a502cd86..cbdbe5899 100644
--- a/scripts/nix/flake.lock
+++ b/scripts/nix/flake.lock
@@ -36,37 +36,7 @@
         "type": "github"
       }
     },
-    "naersk": {
-      "inputs": {
-        "nixpkgs": "nixpkgs"
-      },
-      "locked": {
-        "lastModified": 1717067539,
-        "narHash": "sha256-oIs5EF+6VpHJRvvpVWuqCYJMMVW/6h59aYUv9lABLtY=",
-        "owner": "nix-community",
-        "repo": "naersk",
-        "rev": "fa19d8c135e776dc97f4dcca08656a0eeb28d5c0",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "naersk",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
-      "locked": {
-        "lastModified": 0,
-        "narHash": "sha256-SzDKxseEcHR5KzPXLwsemyTR/kaM9whxeiJohbL04rs=",
-        "path": "/nix/store/qgbn0imyridkb9527v6gnv6z3jzzprb9-source",
-        "type": "path"
-      },
-      "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
-      }
-    },
-    "nixpkgs_2": {
       "locked": {
         "lastModified": 1718229064,
         "narHash": "sha256-ZFav8A9zPNfjZg/wrxh1uZeMJHELRfRgFP+meq01XYk=",
@@ -81,7 +51,7 @@
         "type": "indirect"
       }
     },
-    "nixpkgs_3": {
+    "nixpkgs_2": {
       "locked": {
         "lastModified": 1706487304,
         "narHash": "sha256-LE8lVX28MV2jWJsidW13D2qrHU/RUUONendL2Q/WlJg=",
@@ -100,15 +70,14 @@
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "naersk": "naersk",
-        "nixpkgs": "nixpkgs_2",
+        "nixpkgs": "nixpkgs",
         "rust-overlay": "rust-overlay"
       }
     },
     "rust-overlay": {
       "inputs": {
         "flake-utils": "flake-utils_2",
-        "nixpkgs": "nixpkgs_3"
+        "nixpkgs": "nixpkgs_2"
       },
       "locked": {
         "lastModified": 1718331519,
diff --git a/scripts/nix/flake.nix b/scripts/nix/flake.nix
index 319328d4a..23488f0af 100644
--- a/scripts/nix/flake.nix
+++ b/scripts/nix/flake.nix
@@ -1,7 +1,6 @@
 {
   inputs = {
     nixpkgs.url = "nixpkgs/nixos-23.11";
-    naersk.url = "github:nix-community/naersk";
     flake-utils.url = "github:numtide/flake-utils";
     rust-overlay.url = "github:oxalica/rust-overlay";
   };
@@ -15,7 +14,6 @@
             inherit system;
             overlays = [ (import rust-overlay) ];
           };
-          naersk = pkgs.callPackage inputs.naersk { };
           rust-nightly = pkgs.rust-bin.selectLatestNightlyWith (toolchain: toolchain.default);
 
           # Wrap `cargo-udeps` to ensure it uses a nightly Rust version.
@@ -58,19 +56,14 @@
             buildInputs = rustVersion ++ packages;
             name = "rust-env";
             src = ../../rust;
-            shellHook =
-              ''
-                export LD_LIBRARY_PATH=${pkgs.lib.makeLibraryPath libraries}:$LD_LIBRARY_PATH
-                export XDG_DATA_DIRS=${pkgs.gsettings-desktop-schemas}/share/gsettings-schemas/${pkgs.gsettings-desktop-schemas.name}:${pkgs.gtk3}/share/gsettings-schemas/${pkgs.gtk3.name}:$XDG_DATA_DIRS
-              '';
+
+            LD_LIBRARY_PATH = "${pkgs.lib.makeLibraryPath libraries}:$LD_LIBRARY_PATH${pkgs.lib.makeLibraryPath libraries}:$LD_LIBRARY_PATH";
+            XDG_DATA_DIRS = "${pkgs.gsettings-desktop-schemas}/share/gsettings-schemas/${pkgs.gsettings-desktop-schemas.name}:${pkgs.gtk3}/share/gsettings-schemas/${pkgs.gtk3.name}:$XDG_DATA_DIRS";
+            CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER = "${pkgs.llvmPackages.clangUseLLVM}/bin/clang";
+            CARGO_ENCODED_RUSTFLAGS = "-Clink-arg=-fuse-ld=${pkgs.mold}/bin/mold";
           };
         in
         {
-          packages.firezone-headless-client = naersk.buildPackage {
-            name = "foo";
-            src = ../../rust/headless-client;
-          };
-
           devShells.default = mkShellWithRustVersion [
             (pkgs.rust-bin.fromRustupToolchainFile ../../rust/rust-toolchain.toml)
           ];