libgccjit.rb

# three changes by Charl Botha https://github.com/cpbotha to get this building
# on the M1

# 1. use the iains branch of gcc (see head spec)
# 2. change build config to "--build=aarch64-apple-darwin#{osmajor}"
# 3. remove --with-bugurl

# then build with:
# brew install --verbose --build-from-source -head --formula ./libgccjit.rb
# took about 18 minutes on my M1 MBA

# this seemed successful, but trying to do
# brew reinstall emacs-plus@28 --verbose --with-no-titlebar --with-native-comp

# ... failed on not finding the libgccjit, which I could work around by copying
# those libs to where they could be found

# then it failed on the gccjit smoketest, which I tried to build and run on my
# machine, finally stopping when I could not get it past:

# ld: library not found for -lgcc_s.1.1
# libgccjit.so: error: error invoking gcc driver
# NULL result

# gcc_s.1.1 is there, and reported as linked in by otool -L.  current thinking
# is because I'm using iains branch for libgccjit-11, but standard homebrew
# cask for gcc-11. Taking a break from this, but let me know if you have better
# luck!

class Libgccjit < Formula
  desc "JIT library for the GNU compiler collection"
  homepage "https://gcc.gnu.org/"
  url "https://ftp.gnu.org/gnu/gcc/gcc-11.1.0/gcc-11.1.0.tar.xz"
  sha256 "4c4a6fb8a8396059241c2e674b85b351c26a5d678274007f076957afa1cc9ddf"
  license "GPL-3.0-or-later" => {
    with: "GCC-exception-3.1",
  }

  head "https://github.com/iains/gcc-darwin-arm64.git", branch: "master-wip-apple-si"

  livecheck do
    url :stable
    regex(%r{href=.*?gcc[._-]v?(\d+(?:\.\d+)+)(?:/?["' >]|\.t)}i)
  end

  bottle do
    sha256 big_sur:  "287ce8f8321249e34989748a1406a28f0d6d94c1f23bbea8a3fbabc5d3d162d4"
    sha256 catalina: "026a9c50299fc6c5f0a530e338003422c31974e44fc7a658242e8b7825f47666"
    sha256 mojave:   "b17b18f077040d14ff4b1d3a863473c6fa21ea24b1695799b8fb6a5ebf1b3617"
  end

  # The bottles are built on systems with the CLT installed, and do not work
  # out of the box on Xcode-only systems due to an incorrect sysroot.
  pour_bottle? do
    reason "The bottle needs the Xcode CLT to be installed."
    satisfy { MacOS::CLT.installed? }
  end

  depends_on "gcc" => :test
  depends_on "gmp"
  depends_on "isl"
  depends_on "libmpc"
  depends_on "mpfr"

  uses_from_macos "zlib"

  # GCC bootstraps itself, so it is OK to have an incompatible C++ stdlib
  cxxstdlib_check :skip

  def install
    # GCC will suffer build errors if forced to use a particular linker.
    ENV.delete "LD"

    osmajor = `uname -r`.split(".").first
    pkgversion = "Homebrew GCC #{pkg_version} #{build.used_options*" "}".strip

    # remove #{osmajor} appended to build config name
    args = %W[
      --build=aarch64-apple-darwin#{osmajor}
      --prefix=#{prefix}
      --libdir=#{lib}/gcc/#{version.major}
      --disable-nls
      --enable-checking=release
      --with-gmp=#{Formula["gmp"].opt_prefix}
      --with-mpfr=#{Formula["mpfr"].opt_prefix}
      --with-mpc=#{Formula["libmpc"].opt_prefix}
      --with-isl=#{Formula["isl"].opt_prefix}
      --with-system-zlib
      --with-pkgversion=#{pkgversion}

    ]

    # try to work around: NoMethodError: undefined method `issues_url' for nil:NilClass
    #--with-bugurl=#{tap.issues_url}
    
    # Xcode 10 dropped 32-bit support
    args << "--disable-multilib" if DevelopmentTools.clang_build_version >= 1000

    # System headers may not be in /usr/include
    sdk = MacOS.sdk_path_if_needed
    if sdk
      args << "--with-native-system-header-dir=/usr/include"
      args << "--with-sysroot=#{sdk}"
    end

    # Use -headerpad_max_install_names in the build,
    # otherwise updated load commands won't fit in the Mach-O header.
    # This is needed because `gcc` avoids the superenv shim.
    make_args = ["BOOT_LDFLAGS=-Wl,-headerpad_max_install_names"]

    # Building jit needs --enable-host-shared, which slows down the compiler.
    mkdir "build-jit" do
      system "../configure", *args, "--enable-languages=jit", "--enable-host-shared"
      system "make", *make_args
      system "make", "install"
    end

    # We only install the relevant libgccjit files from libexec and delete the rest.
    Dir["#{prefix}/**/*"].each do |f|
      rm_rf f if !File.directory?(f) && !File.basename(f).to_s.start_with?("libgccjit")
    end
  end

  test do
    (testpath/"test-libgccjit.c").write <<~EOS
      #include <libgccjit.h>
      #include <stdlib.h>
      #include <stdio.h>

      static void create_code (gcc_jit_context *ctxt) {
          gcc_jit_type *void_type = gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_VOID);
          gcc_jit_type *const_char_ptr_type = gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_CONST_CHAR_PTR);
          gcc_jit_param *param_name = gcc_jit_context_new_param (ctxt, NULL, const_char_ptr_type, "name");
          gcc_jit_function *func = gcc_jit_context_new_function (ctxt, NULL, GCC_JIT_FUNCTION_EXPORTED,
                  void_type, "greet", 1, &param_name, 0);
          gcc_jit_param *param_format = gcc_jit_context_new_param (ctxt, NULL, const_char_ptr_type, "format");
          gcc_jit_function *printf_func = gcc_jit_context_new_function (ctxt, NULL, GCC_JIT_FUNCTION_IMPORTED,
                  gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT), "printf", 1, &param_format, 1);
          gcc_jit_rvalue *args[2];
          args[0] = gcc_jit_context_new_string_literal (ctxt, "hello %s");
          args[1] = gcc_jit_param_as_rvalue (param_name);
          gcc_jit_block *block = gcc_jit_function_new_block (func, NULL);
          gcc_jit_block_add_eval (block, NULL, gcc_jit_context_new_call (ctxt, NULL, printf_func, 2, args));
          gcc_jit_block_end_with_void_return (block, NULL);
      }

      int main (int argc, char **argv) {
          gcc_jit_context *ctxt;
          gcc_jit_result *result;
          ctxt = gcc_jit_context_acquire ();
          if (!ctxt) {
              fprintf (stderr, "NULL ctxt");
              exit (1);
          }
          gcc_jit_context_set_bool_option (ctxt, GCC_JIT_BOOL_OPTION_DUMP_GENERATED_CODE, 0);
          create_code (ctxt);
          result = gcc_jit_context_compile (ctxt);
          if (!result) {
              fprintf (stderr, "NULL result");
              exit (1);
          }
          typedef void (*fn_type) (const char *);
          fn_type greet = (fn_type)gcc_jit_result_get_code (result, "greet");
          if (!greet) {
              fprintf (stderr, "NULL greet");
              exit (1);
          }
          greet ("world");
          fflush (stdout);
          gcc_jit_context_release (ctxt);
          gcc_jit_result_release (result);
          return 0;
      }
    EOS

    gcc_major_ver = Formula["gcc"].any_installed_version.major
    gcc = Formula["gcc"].opt_bin/"gcc-#{gcc_major_ver}"
    libs = "#{HOMEBREW_PREFIX}/lib/gcc/#{gcc_major_ver}"

    system gcc.to_s, "-I#{include}", "test-libgccjit.c", "-o", "test", "-L#{libs}", "-lgccjit"
    assert_equal "hello world", shell_output("./test")
  end
end