From f5f53288ccd32e7f37d2b27652399a93d940491c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20Partheym=C3=BCller?=
 <markus.partheymueller@cyberus-technology.de>
Date: Fri, 17 Apr 2020 15:15:57 +0200
Subject: [PATCH] edk2/OVMF: Support build on macOS

In order to use OVMF firmware with e.g. qemu on macOS, these packages
needed to be made macOS ready. This meant choosing the clang build in
this case, because it is the only one working on macOS.

Unfortunately, just using clang on all platforms doesn't work because
there are hardcoded assumptions in the edk2 build system.
---
 .../virtualization/OVMF/default.nix           |  8 +++--
 pkgs/development/compilers/edk2/default.nix   | 36 ++++++++++++++-----
 2 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/pkgs/applications/virtualization/OVMF/default.nix b/pkgs/applications/virtualization/OVMF/default.nix
index e475c4ed78af..e203106587b7 100644
--- a/pkgs/applications/virtualization/OVMF/default.nix
+++ b/pkgs/applications/virtualization/OVMF/default.nix
@@ -17,9 +17,13 @@ let
     throw "Unsupported architecture";
 
   version = lib.getVersion edk2;
+  buildType = if stdenv.isDarwin then
+    "CLANGPDB"
+  else
+    "GCC5";
 in
 
-edk2.mkDerivation projectDscPath {
+edk2.mkDerivation projectDscPath buildType {
   name = "OVMF-${version}";
 
   outputs = [ "out" "fd" ];
@@ -57,6 +61,6 @@ edk2.mkDerivation projectDscPath {
     description = "Sample UEFI firmware for QEMU and KVM";
     homepage = https://github.com/tianocore/tianocore.github.io/wiki/OVMF;
     license = stdenv.lib.licenses.bsd2;
-    platforms = ["x86_64-linux" "i686-linux" "aarch64-linux"];
+    platforms = ["x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin"];
   };
 }
diff --git a/pkgs/development/compilers/edk2/default.nix b/pkgs/development/compilers/edk2/default.nix
index 47aa8e249f8e..2ba02a294880 100644
--- a/pkgs/development/compilers/edk2/default.nix
+++ b/pkgs/development/compilers/edk2/default.nix
@@ -1,4 +1,17 @@
-{ stdenv, fetchgit, fetchpatch, libuuid, python3, iasl, bc }:
+{
+    stdenv,
+    clangStdenv,
+    fetchgit,
+    fetchpatch,
+    libuuid,
+    python3,
+    iasl,
+    bc,
+    clang_9,
+    llvmPackages_9,
+    overrideCC,
+    lib,
+}:
 
 let
   pythonEnv = python3.withPackages (ps: [ps.tkinter]);
@@ -12,7 +25,12 @@ else if stdenv.isAarch64 then
 else
   throw "Unsupported architecture";
 
-edk2 = stdenv.mkDerivation {
+buildStdenv = if stdenv.isDarwin then
+  overrideCC clangStdenv [ clang_9 llvmPackages_9.llvm llvmPackages_9.lld ]
+else
+  stdenv;
+
+edk2 = buildStdenv.mkDerivation {
   pname = "edk2";
   version = "201911";
 
@@ -25,8 +43,10 @@ edk2 = stdenv.mkDerivation {
 
   buildInputs = [ libuuid pythonEnv ];
 
-  makeFlags = [ "-C BaseTools" ];
-  NIX_CFLAGS_COMPILE = "-Wno-return-type -Wno-error=stringop-truncation";
+  makeFlags = [ "-C BaseTools" ]
+    ++ lib.optional (stdenv.isDarwin) [ "BUILD_CC=clang BUILD_CXX=clang++ BUILD_AS=clang" ];
+
+  NIX_CFLAGS_COMPILE = "-Wno-return-type" + lib.optionalString (!stdenv.isDarwin) " -Wno-error=stringop-truncation";
 
   hardeningDisable = [ "format" "fortify" ];
 
@@ -38,15 +58,15 @@ edk2 = stdenv.mkDerivation {
 
   enableParallelBuilding = true;
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     description = "Intel EFI development kit";
     homepage = https://sourceforge.net/projects/edk2/;
     license = licenses.bsd2;
-    platforms = [ "x86_64-linux" "i686-linux" "aarch64-linux" ];
+    platforms = [ "x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin" ];
   };
 
   passthru = {
-    mkDerivation = projectDscPath: attrs: stdenv.mkDerivation ({
+    mkDerivation = projectDscPath: buildType: attrs: buildStdenv.mkDerivation ({
       inherit (edk2) src;
 
       buildInputs = [ bc pythonEnv ] ++ attrs.buildInputs or [];
@@ -65,7 +85,7 @@ edk2 = stdenv.mkDerivation {
 
       buildPhase = ''
         runHook preBuild
-        build -a ${targetArch} -b RELEASE -t GCC5 -p ${projectDscPath} -n $NIX_BUILD_CORES $buildFlags
+        build -a ${targetArch} -b RELEASE -t ${buildType} -p ${projectDscPath} -n $NIX_BUILD_CORES $buildFlags
         runHook postBuild
       '';