From b88f17ed425c339d016ea5333fab2be3d8ff31fa Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Sun, 9 Jan 2022 10:53:58 +0800
Subject: [PATCH] switch to clang-unwrapped, build IRRT with wasm32

---
 flake.nix         |  2 +-
 nac3core/build.rs | 10 ++++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/flake.nix b/flake.nix
index 5a51737b..1701e0c7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -177,7 +177,7 @@
         name = "nac3-dev-shell";
         buildInputs = with pkgs; [
           packages.x86_64-linux.llvm-nac3
-          clang_13
+          llvmPackages_13.clang-unwrapped  # for IRRT
           lld_13
           cargo
           cargo-insta
diff --git a/nac3core/build.rs b/nac3core/build.rs
index c4dcfc8e..c3bff8eb 100644
--- a/nac3core/build.rs
+++ b/nac3core/build.rs
@@ -6,10 +6,16 @@ use std::{
 };
 
 fn main() {
-    let out_dir = env::var("OUT_DIR").unwrap();
     const FILE: &str = "src/codegen/irrt/irrt.c";
     println!("cargo:rerun-if-changed={}", FILE);
+
+    /*
+     * HACK: Sadly, clang doesn't let us emit generic LLVM bitcode.
+     * Compiling for WASM32 and filtering the output with regex is the closest we can get.
+     */
+
     const FLAG: &[&str] = &[
+        "--target=wasm32",
         FILE,
         "-O3",
         "-emit-llvm",
@@ -46,7 +52,7 @@ fn main() {
     let mut llvm_as = Command::new("llvm-as")
         .stdin(Stdio::piped())
         .arg("-o")
-        .arg(&format!("{}/irrt.bc", out_dir))
+        .arg(&format!("{}/irrt.bc", env::var("OUT_DIR").unwrap()))
         .spawn()
         .unwrap();
     llvm_as.stdin.as_mut().unwrap().write_all(filtered_output.as_bytes()).unwrap();