Use zig to build bitcode

BUILDING_FROM_SOURCE.md

@@ -7,15 +7,17 @@ To build the compiler, you need these installed:
 
 * `libunwind` (macOS should already have this one installed)
 * `libc++-dev`
+* [`zig`](https://ziglang.org/download/)
 * a particular version of LLVM
 
 To run the test suite (via `cargo test`), you additionally need to install:
 
 * [`valgrind`](https://www.valgrind.org/) (needs special treatment to [install on macOS](https://stackoverflow.com/a/61359781)]
 
-Some systems may already have `libc++-dev` on them, but if not, you may need to install it. (On Ubuntu, this can be done with `sudo apt-get install libc++-dev`.) macOS systems
-should already have `libunwind`, but other systems will need to install it
-(e.g. with `sudo apt-get install libunwind-dev`).
+Some systems may already have `libc++-dev` on them, but if not, you may need to install it. (On Ubuntu, this can be done with `sudo apt-get install libc++-dev`.)
+MacOS systems should already have `libunwind`, but other systems will need to install it (e.g. with `sudo apt-get install libunwind-dev`).
+
+To install Zig on macOS, use `brew install zig`. To install on Ubuntu, checkout [zig's docs](https://github.com/dryzig/zig-debian/blob/master/README.md).
 
 To see which version of LLVM you need, take a look at `Cargo.toml`, in particular the `branch` section of the `inkwell` dependency. It should have something like `llvmX-Y` where X and Y are the major and minor revisions of LLVM you need.
 

ci/install-ci-libraries.sh

@@ -60,3 +60,11 @@ wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -
 add-apt-repository "${REPO_NAME}"
 apt-get update
 apt-get install -y clang-$LLVM_VERSION lldb-$LLVM_VERSION lld-$LLVM_VERSION clangd-$LLVM_VERSION libc++abi-dev libunwind-dev valgrind
+
+# install zig
+echo 'deb https://dl.bintray.com/dryzig/zig-ubuntu bionic main' | tee -a /etc/apt/sources.list
+apt update
+apt install zig
+
+# symlink llvm tools
+ln -s /usr/bin/llvm-as-10 /usr/local/bin/llvm-as

compiler/builtins/bitcode/.gitignore

@@ -1 +1,4 @@
-lib.ll
+main.ll
+main.o
+src/zig-cache
+zig-cache

compiler/builtins/bitcode/src/lib.c

@@ -1,33 +0,0 @@
-#include <math.h>
-#include <stdbool.h>
-
-// float     -> f32
-// double    -> f64
-// int       -> i16
-// long int  -> i32
-// long long -> i64
-
-bool is_finite_(double num) { return isfinite(num); }
-
-double atan_(double num) { return atan(num); }
-
-long long pow_int_(long long base, long long exp) {
-  int acc = 1;
-
-  while (exp > 1) {
-    if ((exp & 1) == 1) {
-      acc *= base;
-    }
-    exp /= 2;
-    base *= base;
-  }
-
-  // Deal with the final bit of the exponent separately, since
-  // squaring the base afterwards is not necessary and may cause a
-  // needless overflow.
-  if (exp == 1) {
-    acc *= base;
-  }
-
-  return acc;
-}

compiler/builtins/bitcode/src/main.zig

@@ -0,0 +1,18 @@
+const std = @import("std");
+const testing = std.testing;
+
+fn is_finite_(f: f64) bool {
+    return std.math.isFinite(f);
+}
+
+fn atan(f: f64) f64 {
+    return std.math.atan(f);
+}
+
+fn pow_int_(base: i64, exp: i64) i64 {
+    return std.math.pow(i64, base, exp);
+}
+
+// test "basic add functionality" {
+    // testing.expect(add(3, 7) == 10);
+// }

compiler/gen/build.rs

@@ -4,20 +4,27 @@ use std::path::Path;
 use std::process::Command;
 
 fn main() {
-    let src_path = fs::canonicalize("./../builtins/bitcode/src/lib.c")
+    let src_path = fs::canonicalize("./../builtins/bitcode/src/main.zig")
         .expect("Failed to resolve bitcode source");
     let src = src_path.to_str().expect("Invalid src path");
 
     let out_dir = env::var_os("OUT_DIR").unwrap();
-    let dest_path = Path::new(&out_dir).join("builtins.bc");
-    let dest = dest_path.to_str().expect("Invalid dest path");
+    let dest_ll_path = Path::new(&out_dir).join("builtins.ll");
+    let dest_ll = dest_ll_path.to_str().expect("Invalid dest ir path");
+    let dest_bc_path = Path::new(&out_dir).join("builtins.bc");
+    let dest_bc = dest_bc_path.to_str().expect("Invalid dest bc path");
 
-    Command::new("clang")
-        .args(&["-emit-llvm", "-o", dest, "-c", src])
+    Command::new("zig")
+        .args(&["build-obj", src, "-femit-llvm-ir=", dest_ll])
+        .status()
+        .unwrap();
+
+    Command::new("llvm-as")
+        .args(&[dest_ll, "-o", dest_bc])
         .status()
         .unwrap();
 
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-changed={}", src);
-    println!("cargo:rustc-env=BUILTINS_BC={}", dest);
+    println!("cargo:rustc-env=BUILTINS_BC={}", dest_bc);
 }

nix/zig.nix

@@ -2,12 +2,14 @@
 
 if isMacOS
   then
+    # As of 2020-10-25, building Zig from source on MacOS fails
+    # so we just download the binary from their release page
     let
       version = "0.6.0";
       archiveName = "zig-macos-x86_64-${version}+91a1c20e7";
     in
     pkgs.stdenv.mkDerivation {
-      pname = "zig-${version}";
+      pname = "zig";
       version = version;
       buildInputs = [ pkgs.gzip ];
       src = pkgs.fetchurl {
@@ -19,7 +21,9 @@ if isMacOS
       installPhase = ''
         mkdir -p $out/bin
         tar -xf $src
-        cp ${archiveName}/zig $out/bin/zig
+        cp ${archiveName}/zig $out/zig
+        cp -r ${archiveName}/lib $out/lib
+        ln -s "$out/zig" "$out/bin/zig"
         chmod +x $out/bin/zig
       '';
     }

nix/zls.nix

@@ -0,0 +1,29 @@
+{ pkgs, zig }:
+
+# As of 2020-10-25, building zls is not available on Nix
+# For some reason, this hangs on `zig build`. I'll try
+# to figure it our later :(
+
+let
+  rev = "e8c20351d85da8eb4bf22480045b994007284d69";
+in
+pkgs.stdenv.mkDerivation {
+  pname = "zig-language-server";
+  version = rev;
+  src = pkgs.fetchgit {
+    inherit rev;
+    fetchSubmodules = true;
+    url = "https://github.com/zigtools/zls.git";
+    sha256 = "06g8gml1g0fmvcfysy93bd1hb64vjd2v12x3kgxz58kmk5z0168y";
+  };
+  phases = [ "buildPhase" "installPhase" ];
+  buildInputs = [ zig ];
+  buildPhase = ''
+    zig build
+  '';
+  installPhase = ''
+    mkdir -p $out/bin
+    cp ./zig-cache/bin/zls $out/bin/zls
+    chmod +x $out/bin/zls
+  '';
+}

shell.nix

@@ -9,10 +9,11 @@ with {
     ref = "refs/heads/nixpkgs-unstable";
     rev = "502845c3e31ef3de0e424f3fcb09217df2ce6df6";
   }) { };
+
+  isMacOS = builtins.currentSystem == "x86_64-darwin";
 };
 
 let
-  isMacOS = builtins.currentSystem == "x86_64-darwin";
   darwin-frameworks =
     if isMacOS then
       with pkgs.darwin.apple_sdk.frameworks; [
@@ -28,14 +29,15 @@ let
       [ ];
   llvm = pkgs.llvm_10;
   lld = pkgs.lld_10; # this should match llvm's version
+  zig = import ./nix/zig.nix { inherit pkgs isMacOS; };
   inputs =
     [
       # build libraries
       pkgs.rustup
       pkgs.cargo
-      llvm
       pkgs.valgrind
-      (import ./nix/zig.nix { inherit pkgs isMacOS; })
+      zig
+      llvm
       # llb deps
       pkgs.libffi
       pkgs.libxml2
@@ -44,6 +46,7 @@ let
       lld
       # dev tools
       pkgs.rust-analyzer
+      # (import ./nix/zls.nix { inherit pkgs zig; })
       pkgs.ccls
     ];
 in pkgs.mkShell {