{ stdenv, targetPackages
, fetchurl, fetchgit, fetchzip, file, python2, tzdata, ps
, llvm, jemalloc, ncurses, darwin, rustPlatform, git, cmake, curl
, which, libffi, gdb
, version
, forceBundledLLVM ? false
, src
, configureFlags ? []
, patches
, targets
, targetPatches
, targetToolchains
, doCheck ? true
, broken ? false
, buildPlatform, hostPlatform
} @ args:

let
  inherit (stdenv.lib) optional optionalString;
  inherit (darwin.apple_sdk.frameworks) Security;

  llvmShared = llvm.override { enableSharedLibraries = true; };

  target = builtins.replaceStrings [" "] [","] (builtins.toString targets);
in

stdenv.mkDerivation {
  name = "rustc-${version}";
  inherit version;

  inherit src;

  __darwinAllowLocalNetworking = true;

  # The build will fail at the very end on AArch64 without this.
  dontUpdateAutotoolsGnuConfigScripts = if stdenv.isAarch64 then true else null;

  # Running the default `strip -S` command on Darwin corrupts the
  # .rlib files in "lib/".
  #
  # See https://github.com/NixOS/nixpkgs/pull/34227
  stripDebugList = if stdenv.isDarwin then [ "bin" ] else null;

  NIX_LDFLAGS = optionalString stdenv.isDarwin "-rpath ${llvmShared}/lib";

  # Enable nightly features in stable compiles (used for
  # bootstrapping, see https://github.com/rust-lang/rust/pull/37265).
  # This loosens the hard restrictions on bootstrapping-compiler
  # versions.
  RUSTC_BOOTSTRAP = "1";

  # Increase codegen units to introduce parallelism within the compiler.
  RUSTFLAGS = "-Ccodegen-units=10";

  # We need rust to build rust. If we don't provide it, configure will try to download it.
  # Reference: https://github.com/rust-lang/rust/blob/master/src/bootstrap/configure.py
  configureFlags = configureFlags
                ++ [ "--enable-local-rust" "--local-rust-root=${rustPlatform.rust.rustc}" "--enable-rpath" ]
                ++ [ "--enable-vendor" ]
                # ++ [ "--jemalloc-root=${jemalloc}/lib"
                ++ [ "--default-linker=${targetPackages.stdenv.cc}/bin/cc" ]
                ++ optional (!forceBundledLLVM) [ "--enable-llvm-link-shared" ]
                ++ optional (targets != []) "--target=${target}"
                ++ optional (!forceBundledLLVM) "--llvm-root=${llvmShared}";

  # The boostrap.py will generated a Makefile that then executes the build.
  # The BOOTSTRAP_ARGS used by this Makefile must include all flags to pass
  # to the bootstrap builder.
  postConfigure = ''
    substituteInPlace Makefile --replace 'BOOTSTRAP_ARGS :=' 'BOOTSTRAP_ARGS := --jobs $(NIX_BUILD_CORES)'
  '';

  patches = patches ++ targetPatches;

  # the rust build system complains that nix alters the checksums
  dontFixLibtool = true;

  passthru.target = target;

  postPatch = ''
    patchShebangs src/etc

    # Fix dynamic linking against llvm
    #${optionalString (!forceBundledLLVM) ''sed -i 's/, kind = \\"static\\"//g' src/etc/mklldeps.py''}

    # Fix the configure script to not require curl as we won't use it
    sed -i configure \
      -e '/probe_need CFG_CURL curl/d'

    # Fix the use of jemalloc prefixes which our jemalloc doesn't have
    # TODO: reenable if we can figure out how to get our jemalloc to work
    #[ -f src/liballoc_jemalloc/lib.rs ] && sed -i 's,je_,,g' src/liballoc_jemalloc/lib.rs
    #[ -f src/liballoc/heap.rs ] && sed -i 's,je_,,g' src/liballoc/heap.rs # Remove for 1.4.0+

    # Disable fragile tests.
    rm -vr src/test/run-make/linker-output-non-utf8 || true
    rm -vr src/test/run-make/issue-26092 || true

    # Remove test targeted at LLVM 3.9 - https://github.com/rust-lang/rust/issues/36835
    rm -vr src/test/run-pass/issue-36023.rs || true

    # Disable test getting stuck on hydra - possible fix:
    # https://reviews.llvm.org/rL281650
    rm -vr src/test/run-pass/issue-36474.rs || true

    # On Hydra: `TcpListener::bind(&addr)`: Address already in use (os error 98)'
    sed '/^ *fn fast_rebind()/i#[ignore]' -i src/libstd/net/tcp.rs

    # Useful debugging parameter
    # export VERBOSE=1
  '' + optionalString stdenv.isDarwin ''
    # Disable all lldb tests.
    # error: Can't run LLDB test because LLDB's python path is not set
    rm -vr src/test/debuginfo/*
    rm -v src/test/run-pass/backtrace-debuginfo.rs

    # error: No such file or directory
    rm -v src/test/run-pass/issue-45731.rs

    # Disable tests that fail when sandboxing is enabled.
    substituteInPlace src/libstd/sys/unix/ext/net.rs \
        --replace '#[test]' '#[test] #[ignore]'
    substituteInPlace src/test/run-pass/env-home-dir.rs \
        --replace 'home_dir().is_some()' true
    rm -v src/test/run-pass/fds-are-cloexec.rs  # FIXME: pipes?
    rm -v src/test/run-pass/sync-send-in-std.rs  # FIXME: ???
  '';

  # rustc unfortunately need cmake for compiling llvm-rt but doesn't
  # use it for the normal build. This disables cmake in Nix.
  dontUseCmakeConfigure = true;

  # ps is needed for one of the test cases
  nativeBuildInputs =
    [ file python2 ps rustPlatform.rust.rustc git cmake
      which libffi
    ]
    # Only needed for the debuginfo tests
    ++ optional (!stdenv.isDarwin) gdb;

  buildInputs = [ ncurses ] ++ targetToolchains
    ++ optional stdenv.isDarwin Security
    ++ optional (!forceBundledLLVM) llvmShared;

  outputs = [ "out" "man" "doc" ];
  setOutputFlags = false;

  # Disable codegen units for the tests.
  preCheck = ''
    export RUSTFLAGS=
    export TZDIR=${tzdata}/share/zoneinfo
  '' +
  # Ensure TMPDIR is set, and disable a test that removing the HOME
  # variable from the environment falls back to another home
  # directory.
  optionalString stdenv.isDarwin ''
    export TMPDIR=/tmp
    sed -i '28s/home_dir().is_some()/true/' ./src/test/run-pass/env-home-dir.rs
  '';

  inherit doCheck;

  configurePlatforms = [];

  # https://github.com/NixOS/nixpkgs/pull/21742#issuecomment-272305764
  # https://github.com/rust-lang/rust/issues/30181
  # enableParallelBuilding = false;

  meta = with stdenv.lib; {
    homepage = https://www.rust-lang.org/;
    description = "A safe, concurrent, practical language";
    maintainers = with maintainers; [ madjar cstrahan wizeman globin havvy wkennington ];
    license = [ licenses.mit licenses.asl20 ];
    platforms = platforms.linux ++ platforms.darwin;
    broken = broken;
  };
}