add llvm flake

flake.nix

@@ -27,6 +27,11 @@
               description = "LaTeX flake";
             };
 
+          llvm = {
+              path = ./llvm;
+              description = "LLVM-build flake";
+            };
+
           python = {
               path = ./python;
               description = "Python flake";

llvm/flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1701680307,
+        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1702312524,
+        "narHash": "sha256-gkZJRDBUCpTPBvQk25G0B7vfbpEYM5s5OZqghkjZsnE=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a9bf124c46ef298113270b1f84a164865987a91c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

llvm/flake.nix

@@ -0,0 +1,49 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }: 
+    flake-utils.lib.eachDefaultSystem (system:
+        let
+        pkgs = import nixpkgs {
+        inherit system;
+        config = { allowUnfree = true; };
+        };
+        gccForLibs = pkgs.stdenv.cc.cc;
+        in {
+        name = "LLVM";
+        description = "LLVM-build toolchain";
+        devShell = pkgs.mkShell {
+        buildInputs = with pkgs; [
+        bashInteractive
+        python3
+        ninja
+        cmake
+        llvmPackages_17.llvm
+        ];
+# where to find libgcc
+        NIX_LDFLAGS="-L${gccForLibs}/lib/gcc/${pkgs.targetPlatform.config}/${gccForLibs.version}";
+# teach clang about C startup file locations
+        CFLAGS="-B${gccForLibs}/lib/gcc/${pkgs.targetPlatform.config}/${gccForLibs.version} -B ${pkgs.stdenv.cc.libc}/lib";
+
+        cmakeFlags = [
+          "-DGCC_INSTALL_PREFIX=${pkgs.gcc}"
+            "-DC_INCLUDE_DIRS=${pkgs.stdenv.cc.libc.dev}/include"
+            "-GNinja"
+# Debug for debug builds
+            "-DCMAKE_BUILD_TYPE=Release"
+# inst will be our installation prefix
+            "-DCMAKE_INSTALL_PREFIX=../inst"
+            "-DLLVM_INSTALL_TOOLCHAIN_ONLY=ON"
+# change this to enable the projects you need
+            "-DLLVM_ENABLE_PROJECTS=clang"
+# enable libcxx* to come into play at runtimes
+            "-DLLVM_ENABLE_RUNTIMES=libcxx;libcxxabi"
+# this makes llvm only to produce code for the current platform, this saves CPU time, change it to what you need
+            "-DLLVM_TARGETS_TO_BUILD=host"
+            ];
+        };
+        });
+}