shell.nix: Add nix shell

Author: Samir-Rashid

shell.nix

@@ -0,0 +1,65 @@
+# Licensed under the Apache License, Version 2.0 or the MIT License.
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+# Copyright Tock Contributors 2022.
+
+# Shell expression for the Nix package manager
+#
+# This nix expression creates an environment with necessary packages installed:
+#
+#  * rust
+#
+# To use:
+#
+#  $ nix-shell
+#
+
+{ pkgs ? import <nixpkgs> {}, withUnfreePkgs ? false }:
+
+with builtins;
+let
+  inherit (pkgs) stdenv lib;
+
+  rust_overlay = import (builtins.fetchTarball "https://github.com/oxalica/rust-overlay/archive/master.tar.gz");
+  nixpkgs = import <nixpkgs> { overlays = [ rust_overlay ]; };
+
+  # Get a custom cross-compile capable Rust install of a specific channel and
+  # build. Tock expects a specific version of Rust with a selection of targets
+  # and components to be present.
+  rustBuild = (
+    nixpkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml
+  );
+
+in
+  pkgs.mkShell {
+    name = "tock-dev";
+
+    buildInputs = with pkgs; [
+      # --- Toolchains ---
+      rustBuild
+      openocd
+
+      # --- Convenience and support packages ---
+      python3Full
+      tockloader
+
+      # Required for tools/print_tock_memory_usage.py
+      python3Packages.cxxfilt
+
+
+      # --- CI support packages ---
+      qemu
+    ];
+
+    LD_LIBRARY_PATH="${stdenv.cc.cc.lib}/lib64:$LD_LIBRARY_PATH";
+
+    # Instruct the Tock gnumake-based build system to not check for rustup and
+    # assume all requirend tools are installed and available in the $PATH
+    NO_RUSTUP = "1";
+
+    # The defaults "objcopy" and "objdump" are wrong (stem from the standard
+    # environment for x86), use "llvm-obj{copy,dump}" as defined in the makefile
+    shellHook = ''
+      unset OBJCOPY
+      unset OBJDUMP
+    '';
+  }