add more crates

Signed-off-by: xermicus <cyrill@parity.io>

crates/builtins/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "compiler-builtins"
+version = "0.1.0"
+edition = "2021"
+build = "build.rs"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

crates/builtins/build.rs

@@ -0,0 +1,31 @@
+use std::{env, fs, io::Read, path::Path, process::Command};
+
+fn main() {
+    let lib = "libclang_rt.builtins-riscv32.a";
+    let mut llvm_lib_dir = String::new();
+
+    Command::new("llvm-config")
+        .args(["--libdir"])
+        .output()
+        .expect("llvm-config should be able to provide LD path")
+        .stdout
+        .as_slice()
+        .read_to_string(&mut llvm_lib_dir)
+        .expect("llvm-config output should be utf8");
+
+    let lib_path = std::path::PathBuf::from(llvm_lib_dir.trim())
+        .join("linux")
+        .join(lib);
+    let archive = fs::read(lib_path).expect("clang builtins for riscv32 not fonud");
+
+    let out_dir = env::var_os("OUT_DIR").expect("has OUT_DIR");
+    let archive_path = Path::new(&out_dir).join(lib);
+    let len = archive.len();
+    std::fs::write(archive_path, &archive).expect("can write to OUT_DIR");
+
+    let src_path = Path::new(&out_dir).join("compiler_rt.rs");
+    let src = format!("pub static COMPILER_RT: &[u8; {len}] = include_bytes!(\"{lib}\");");
+    fs::write(src_path, src).expect("can write to OUT_DIR");
+
+    println!("cargo:rerun-if-changed=build.rs");
+}

crates/builtins/src/lib.rs

@@ -0,0 +1 @@
+include!(concat!(env!("OUT_DIR"), "/compiler_rt.rs"));