optionally build bellman-cuda from source if no build is found

crates/gpu-ffi/Cargo.toml

@@ -20,7 +20,9 @@ num_cpus = "1"
 crossbeam = "0.8"
 
 [build-dependencies]
+era_cudart_sys.workspace = true
 bindgen = "0.59.1"
+cmake = "0.1"
 
 [dev-dependencies]
 rand = "0.4"

crates/gpu-ffi/build.rs

@@ -1,6 +1,8 @@
 extern crate bindgen;
+use era_cudart_sys::get_cuda_lib_path;
+use std::env::var;
+use std::path::Path;
 use std::{env, path::PathBuf};
-
 // build.rs
 
 fn main() {
@@ -53,16 +55,27 @@ fn generate_bindings(bellman_cuda_path: &str) {
 }
 
 fn link_multiexp_library(bellman_cuda_path: &str) {
-    let kind = "static";
-    let name = "bellman-cuda";
-
-    println!("cargo:rustc-link-lib=dylib=stdc++");
-    println!("cargo:rustc-link-search=native=/usr/local/cuda/lib64");
-    println!("cargo:rustc-link-lib=dylib=cudart");
-    println!("cargo:rustc-link-lib=static=cudadevrt");
-    println!(
-        "cargo:rustc-link-search=native={}/build/src",
-        bellman_cuda_path
-    );
-    println!("cargo:rustc-link-lib={}={}", kind, name);
+    let bellman_cuda_lib_path = if Path::new(bellman_cuda_path).join("build").exists() {
+        Path::new(bellman_cuda_path)
+            .join("build")
+            .join("src")
+            .to_str()
+            .unwrap()
+            .to_string()
+    } else {
+        let cudaarchs = var("CUDAARCHS").unwrap_or("native".to_string());
+        let dst = cmake::Config::new(bellman_cuda_path)
+            .profile("Release")
+            .define("CMAKE_CUDA_ARCHITECTURES", cudaarchs)
+            .build();
+        dst.to_str().unwrap().to_string()
+    };
+    println!("cargo:rustc-link-search=native={bellman_cuda_lib_path}");
+    println!("cargo:rustc-link-lib=static=bellman-cuda");
+    let cuda_lib_path = get_cuda_lib_path().unwrap();
+    let cuda_lib_path_str = cuda_lib_path.to_str().unwrap();
+    println!("cargo:rustc-link-search=native={cuda_lib_path_str}");
+    println!("cargo:rustc-link-lib=cudart");
+    #[cfg(target_os = "linux")]
+    println!("cargo:rustc-link-lib=stdc++");
 }