revive llvm builder utility (#154)

Pre-eliminary support for LLVM releases and resolc binary releases by streamlining the build process for all supported hosts platforms.

- Introduce the revive-llvm-builder crate with the revive-llvm builder utilty.
- Do not rely on the LLVM dependency in $PATH to decouple the system LLVM installation from the LLVM host dependency.
- Fix the emscripten build by decoupling the host and native LLVM dependencies. Thus allowing a single LLVM emscripten release that can be used on any host platform.
- An example Dockerfile building an alpine container with a fully statically linked resolc ELF binary.
- Remove the Debian builder utilities and workflow.

crates/builtins/Cargo.toml

@@ -8,4 +8,5 @@ authors.workspace = true
 build = "build.rs"
 description = "compiler builtins for the revive compiler"
 
-[dependencies]
+[build-dependencies]
+revive-build-utils = { workspace = true }

crates/builtins/build.rs

@@ -3,25 +3,32 @@ use std::{env, fs, io::Read, path::Path, process::Command};
 pub const BUILTINS_ARCHIVE_FILE: &str = "libclang_rt.builtins-riscv64.a";
 
 fn main() {
-    let mut llvm_lib_dir = String::new();
+    println!(
+        "cargo:rerun-if-env-changed={}",
+        revive_build_utils::REVIVE_LLVM_HOST_PREFIX
+    );
 
-    Command::new("llvm-config")
-        .args(["--libdir"])
+    let llvm_config = revive_build_utils::llvm_host_tool("llvm-config");
+    let mut llvm_lib_dir = String::new();
+    Command::new(&llvm_config)
+        .arg("--libdir")
         .output()
-        .expect("llvm-config should be able to provide LD path")
+        .unwrap_or_else(|_| {
+            panic!(
+                "{} should be able to provide LD path",
+                llvm_config.display()
+            )
+        })
         .stdout
         .as_slice()
         .read_to_string(&mut llvm_lib_dir)
         .expect("llvm-config output should be utf8");
 
-    let mut lib_path = std::path::PathBuf::from(llvm_lib_dir.trim())
-        .join("linux")
+    let lib_path = revive_build_utils::llvm_lib_dir()
+        .join("unknown")
         .join(BUILTINS_ARCHIVE_FILE);
-    if !lib_path.exists() {
-        lib_path = std::path::PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap())
-            .join(BUILTINS_ARCHIVE_FILE);
-    }
-    let archive = fs::read(lib_path).expect("clang builtins not found");
+    let archive = fs::read(&lib_path).expect("clang builtins not found");
+    println!("cargo:rerun-if-env-changed={}", lib_path.display());
 
     let out_dir = env::var_os("OUT_DIR").expect("has OUT_DIR");
     let archive_path = Path::new(&out_dir).join(BUILTINS_ARCHIVE_FILE);