Create a dev env with the cheri llvm toolchain

We build the toolchain in another repository because derivations doesn't allow internet connection,
which is required by cheribuild.

In the future we may want to build the toolchain using cmake directly
from the llvm repository.

Signed-off-by: Douglas Reis <[email protected]>

Author: engdoreis

flake.nix

@@ -113,6 +113,10 @@
             libffi
           ];
         };
+        llvm_cheri = pkgs.mkShell {
+          name = "llvm_cheri";
+          packages = with lowrisc_pkgs; [llvm_cheri];
+        };
       };
       formatter = pkgs.alejandra;
     });

pkgs/default.nix

@@ -23,6 +23,9 @@
   cheriot-sim = pkgs.callPackage ./cheriot-sim.nix {};
   cheriot-audit = pkgs.callPackage ./cheriot-audit.nix {};
 
+  # Cheri
+  llvm_cheri = pkgs.callPackage ./llvm_cheri.nix {};
+
   verilator_caliptra = pkgs.callPackage ./verilator_caliptra.nix {};
 
   # IT packages

pkgs/llvm_cheri.nix

@@ -0,0 +1,41 @@
+# Copyright lowRISC contributors.
+#
+# SPDX-License-Identifier: MIT
+{
+  fetchzip,
+  stdenv,
+  zlib,
+  zstd,
+  ncurses6,
+  autoPatchelfHook,
+}:
+stdenv.mkDerivation rec {
+  name = "cheri-llvm";
+  version = "17.0.1.r01";
+  src = fetchzip {
+    # We build the toolchain in another repository because derivations doesn't allow internet
+    # connection, which is required by cheribuild.
+    url = "https://github.com/engdoreis/cheribuild/releases/download/v${version}/cheri-std093-sdk.tar.gz";
+    hash = "sha256-/6FGm1Ot9sFZ71FIThtLV2KFjhSfnc5w32OucCZmDfc=";
+  };
+
+  dontConfigure = true;
+  dontBuild = true;
+
+  buildInputs = [
+    stdenv.cc.cc.lib
+    ncurses6
+    zlib
+    zstd
+  ];
+  nativeBuildInputs = [autoPatchelfHook];
+
+  installPhase = ''
+    mkdir -p $out
+    cp -R ./cheri-std093-sdk/* $out
+  '';
+
+  meta = {
+    platforms = ["x86_64-linux"];
+  };
+}