use nixpkgs 19.03

* too much breakage on nixos-unstable
* we should track upstream yosys/nextpnr more closely than nixpkgs does

README.md

@@ -15,7 +15,14 @@ Softcore system-on-chip on the Lattice ECP5 Versa board, built with a 100% Veril
 * 100MHz clock frequency.
 * Runs a Rust "hello world" program.
 
-Use nixpkgs unstable (known to work with ae71c13). Check https://nixbld.m-labs.hk/project/fpga for the status of the build with other nixpkgs versions.
+Use nixpkgs 19.03. If you are unfamiliar with Nix and just installed it on another (non-NixOS) distribution, simply run:
+
+```
+$ nix-channel --remove nixpkgs
+$ nix-channel --add https://nixos.org/channels/nixos-19.03 nixpkgs
+$ nix-channel --update
+
+```
 
 Optional: set up the M-Labs key and binary substituter for Nix (otherwise Nix will recompile LLVM, rustc, etc. on your machine).
 Create the file ``~/.config/nix/nix.conf`` with the following contents:
@@ -27,6 +34,8 @@ trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDS
 
 Run ``nix-build -A simplesoc_ecp5 release.nix``
 
+You can also build manually and use your distribution's packages, but YMMV.
+
 Bypass the ispCLOCK device using the jumpers on your board.
 
 Create a ``versa.cfg`` file with:

compilers/rust-riscv32i-crates.nix

@@ -1,29 +1,21 @@
-{ stdenv, rustc, fetchFromGitHub }:
-let
-  compiler-builtins-src = fetchFromGitHub {
-    owner = "rust-lang-nursery";
-    repo = "compiler-builtins";
-    rev = "0.1.12";
-    sha256 = "0hkssvrh952kcz7w7aws3pqr05barg3qppqpji641b35xpbg9gyg";
-  };
-in
-  stdenv.mkDerivation {
-    name = "rust-riscv32i-crates";
-    src = rustc.src;
-    phases = [ "unpackPhase" "buildPhase" ];
-    buildPhase = ''
-      destdir=$out/lib/rustlib/riscv32i-unknown-none-elf/lib/
-      rustc="${rustc}/bin/rustc --out-dir ''${destdir} -L ''${destdir} --target riscv32i-unknown-none-elf -g -C opt-level=s --crate-type rlib"
+{ stdenv, rustc }:
+stdenv.mkDerivation {
+  name = "rust-riscv32i-crates";
+  src = rustc.src;
+  phases = [ "unpackPhase" "buildPhase" ];
+  buildPhase = ''
+    destdir=$out/lib/rustlib/riscv32i-unknown-none-elf/lib/
+    rustc="${rustc}/bin/rustc --out-dir ''${destdir} -L ''${destdir} --target riscv32i-unknown-none-elf -g -C opt-level=s --crate-type rlib"
 
-      mkdir -p ''${destdir}
-      export RUSTC_BOOTSTRAP=1
-      ''${rustc} --crate-name core src/libcore/lib.rs
-      ''${rustc} --crate-name compiler_builtins ${compiler-builtins-src}/src/lib.rs --cfg 'feature="compiler-builtins"' --cfg 'feature="mem"'
-    '';
-    #  ''${rustc} --crate-name alloc src/liballoc/lib.rs
-    #  ''${rustc} --crate-name libc ${./libc_mini.rs}
-    #  ''${rustc} --crate-name unwind src/libunwind/lib.rs
-    #  ''${rustc} --crate-name std src/libstd/lib.rs
-    #  ''${rustc} -Cpanic=abort --crate-name panic_abort src/libpanic_abort/lib.rs
-    #  ''${rustc} -Cpanic=unwind --crate-name panic_unwind src/libpanic_unwind/lib.rs --cfg llvm_libunwind
-  }
+    mkdir -p ''${destdir}
+    export RUSTC_BOOTSTRAP=1
+    ''${rustc} --crate-name core src/libcore/lib.rs
+    ''${rustc} --crate-name compiler_builtins src/libcompiler_builtins/src/lib.rs --cfg 'feature="compiler-builtins"' --cfg 'feature="mem"'
+  '';
+  #  ''${rustc} --crate-name alloc src/liballoc/lib.rs
+  #  ''${rustc} --crate-name libc ${./libc_mini.rs}
+  #  ''${rustc} --crate-name unwind src/libunwind/lib.rs
+  #  ''${rustc} --crate-name std src/libstd/lib.rs
+  #  ''${rustc} -Cpanic=abort --crate-name panic_abort src/libpanic_abort/lib.rs
+  #  ''${rustc} -Cpanic=unwind --crate-name panic_unwind src/libpanic_unwind/lib.rs --cfg llvm_libunwind
+}

overlay.nix

@@ -1,5 +1,73 @@
 self: super:
 rec {
+  yosys = super.yosys.overrideAttrs(oa: rec {
+    name = "yosys-${version}";
+    version = "2019-07-27";
+    srcs = [
+      (super.fetchFromGitHub {
+        owner  = "yosyshq";
+        repo   = "yosys";
+        rev    = "6538671c84a12114a991d59569eede3e0d368758";
+        sha256 = "1l6v94a9vh9krmfsmd3v8l8xciwf028xvg93qf80s8a75djm7bc3";
+        name   = "yosys";
+      })
+
+      # NOTE: the version of abc used here is synchronized with
+      # the one in the yosys Makefile of the version above;
+      # keep them the same for quality purposes.
+      (super.fetchFromGitHub {
+        owner  = "berkeley-abc";
+        repo   = "abc";
+        rev    = "5776ad07e7247993976bffed4802a5737c456782";
+        sha256 = "1la4idmssg44rp6hd63sd5vybvs3vr14yzvwcg03ls37p39cslnl";
+        name   = "yosys-abc";
+      })
+    ];
+    buildInputs = oa.buildInputs ++ [ super.zlib ];
+  });
+  nextpnr = super.nextpnr.overrideAttrs(oa: rec {
+    name = "nextpnr-${version}";
+    version = "2019-07-22";
+    src = super.fetchFromGitHub {
+      owner  = "yosyshq";
+      repo   = "nextpnr";
+      rev    = "ba050c21b94e816f9dd69f69b23ad5105858f401";
+      sha256 = "1wxsv1lcbi6bvv5vryvjz9mj530iva85wh6b6pvnfff2i4yc3p9q";
+    };
+    buildInputs = oa.buildInputs ++ [ super.eigen ];
+    cmakeFlags = oa.cmakeFlags ++ [ "-DUSE_OPENMP=ON" ];
+  });
+  icestorm = super.icestorm.overrideAttrs(oa: rec {
+    name = "icestorm-${version}";
+    version = "2019-07-03";
+    src = super.fetchFromGitHub {
+      owner  = "cliffordwolf";
+      repo   = "icestorm";
+      rev    = "792cef084a751e32f541332feb4905f8e49e9943";
+      sha256 = "115qmgcz5ndw4z8ivk1cdlz6i2dzhq195gr8y4fjrjcb5jlacz23";
+    };
+  });
+  trellis = super.trellis.overrideAttrs(oa: rec {
+    name = "trellis-${version}";
+    version = "2019-07-18";
+    srcs = [
+      (super.fetchFromGitHub {
+         owner  = "symbiflow";
+         repo   = "prjtrellis";
+         rev    = "b27c0da5d20a4c105fe9be2b5f8d859316613f44";
+         sha256 = "12jcs64agv5yhqq4zwjp2vd9y248608hz1gj187g1cfqrv0yc8d5";
+         name   = "trellis";
+       })
+      (super.fetchFromGitHub {
+        owner  = "symbiflow";
+        repo   = "prjtrellis-db";
+        rev    = "b4d626b6402c131e9a035470ffe4cf33ccbe7986";
+        sha256 = "0k26lq6c049ja8hhqcljwjb1y5k4gcici23l2n86gyp83jr03ilx";
+        name   = "database";
+      })
+    ];
+  });
+
   llvm_7 = super.llvm_7.overrideAttrs(oa: {
     name = oa.name + "-riscv";
     cmakeFlags = oa.cmakeFlags ++ ["-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=RISCV"];

release.nix

@@ -3,7 +3,7 @@ let
   pkgs = import <nixpkgs> { overlays = [ (import ./overlay.nix) ]; };
   hx = import ./default.nix { inherit pkgs; };
   jobs = hx // {
-    inherit (pkgs) llvm_7 rustc cargo cargo-vendor;
+    inherit (pkgs) yosys nextpnr icestorm trellis llvm_7 rustc cargo cargo-vendor;
 
     helloworld_ecp5 = import ./examples/helloworld_ecp5.nix { inherit pkgs hx; };
     helloworld_kintex7 = import ./examples/helloworld_kintex7.nix { inherit pkgs hx; };