fix issues with flake.nix (#10)

Author: khaser

README.md

@@ -6,7 +6,7 @@ TODO
 ## Getting dev shell
 * Install `nix`:
 ```
-$ sh <(curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install) --no-daemon
+sh <(curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install) --no-daemon
 ```
 * Enable flakes experimental feature:
 ```
@@ -19,3 +19,11 @@ nix develop
 ```
 * (Optional) Setup [direnv](https://github.com/direnv/direnv) to enter into nix shell automatically
 
+
+## Building
+
+Inside nix shell:
+```
+cmake $cmakeFlags -S llvm -B build
+ninja -C build
+```

flake.nix

@@ -11,41 +11,44 @@
     let
       pkgs = import nixpkgs { inherit system; };
       gccForLibs = pkgs.stdenv.cc.cc;
-    in {
-      devShell = pkgs.mkShell {
-        name = "llvm-env";
+    in rec {
+
+      defaultPackage = pkgs.stdenv.mkDerivation {
+        name = "llvm";
+
+        dontUnpack = true;
 
         buildInputs = with pkgs; [
           python3
           ninja
           cmake
-          llvmPackages_latest.llvm
-          verilator
         ];
 
-        # where to find libgcc
-        NIX_LDFLAGS="-L${gccForLibs}/lib/gcc/${system}/${gccForLibs.version}";
-        # teach clang about C startup file locations
-        CFLAGS="-B${gccForLibs}/lib/gcc/${system}/${gccForLibs.version} -B ${pkgs.stdenv.cc.libc}/lib";
-
         cmakeFlags = [
-          "-DGCC_INSTALL_PREFIX=${pkgs.gcc}"
-          "-DC_INCLUDE_DIRS=${pkgs.stdenv.cc.libc.dev}/include"
-          "-GNinja"
-          # Debug for debug builds
-          "-DCMAKE_BUILD_TYPE=Release"
-          # inst will be our installation prefix
-          "-DCMAKE_INSTALL_PREFIX=../inst"
-          "-DLLVM_INSTALL_TOOLCHAIN_ONLY=ON"
-          # change this to enable the projects you need
-          "-DLLVM_ENABLE_PROJECTS=clang"
-          # enable libcxx* to come into play at runtimes
-          "-DLLVM_ENABLE_RUNTIMES=libcxx;libcxxabi"
-          # this makes llvm only to produce code for the current platform, this saves CPU time, change it to what you need
-          "-DLLVM_TARGETS_TO_BUILD=host"
+            "-DUSE_DEPRECATED_GCC_INSTALL_PREFIX=1"
+            "-DGCC_INSTALL_PREFIX=${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"
+            "-S ${self}/llvm"
         ];
       };
 
+      devShell = (defaultPackage.overrideAttrs (oldAttrs: {
+        name = "llvm-env";
+        buildInputs = oldAttrs.buildInputs ++ (with pkgs; [ verilator ]);
+      }));
+
     });
 }