1 files changed, 100 insertions, 0 deletions
diff --git a/third_party/rust/cranelift-codegen/build.rs b/third_party/rust/cranelift-codegen/build.rs
new file mode 100644
index 0000000000..c456908845
--- /dev/null
+++ b/third_party/rust/cranelift-codegen/build.rs
@@ -0,0 +1,100 @@
+// Build script.
+//
+// This program is run by Cargo when building cranelift-codegen. It is used to generate Rust code from
+// the language definitions in the cranelift-codegen/meta directory.
+//
+// Environment:
+//
+// OUT_DIR
+//     Directory where generated files should be placed.
+//
+// TARGET
+//     Target triple provided by Cargo.
+//
+// The build script expects to be run from the directory where this build.rs file lives. The
+// current directory is used to find the sources.
+
+use cranelift_codegen_meta as meta;
+
+use std::env;
+use std::process;
+use std::time::Instant;
+
+fn main() {
+    let start_time = Instant::now();
+
+    let out_dir = env::var("OUT_DIR").expect("The OUT_DIR environment variable must be set");
+    let target_triple = env::var("TARGET").expect("The TARGET environment variable must be set");
+
+    let new_backend_isas = if env::var("CARGO_FEATURE_X64").is_ok() {
+        // The x64 (new backend for x86_64) is a bit particular: it only requires generating
+        // the shared meta code; the only ISA-specific code is for settings.
+        vec![meta::isa::Isa::X86]
+    } else {
+        Vec::new()
+    };
+
+    // Configure isa targets using the old backend.
+    let isa_targets = meta::isa::Isa::all()
+        .iter()
+        .cloned()
+        .filter(|isa| {
+            let env_key = format!("CARGO_FEATURE_{}", isa.to_string().to_uppercase());
+            env::var(env_key).is_ok()
+        })
+        .collect::<Vec<_>>();
+
+    let old_backend_isas = if new_backend_isas.is_empty() && isa_targets.is_empty() {
+        // Try to match native target.
+        let target_name = target_triple.split('-').next().unwrap();
+        let isa = meta::isa_from_arch(&target_name).expect("error when identifying target");
+        println!("cargo:rustc-cfg=feature=\"{}\"", isa);
+        vec![isa]
+    } else {
+        isa_targets
+    };
+
+    let cur_dir = env::current_dir().expect("Can't access current working directory");
+    let crate_dir = cur_dir.as_path();
+
+    // Make sure we rebuild if this build script changes (will not happen with
+    // if the path to this file contains non-UTF-8 bytes).
+    println!(
+        "cargo:rerun-if-changed={}",
+        crate_dir.join("build.rs").to_str().unwrap()
+    );
+
+    if let Err(err) = meta::generate(&old_backend_isas, &new_backend_isas, &out_dir) {
+        eprintln!("Error: {}", err);
+        process::exit(1);
+    }
+
+    if env::var("CRANELIFT_VERBOSE").is_ok() {
+        for isa in &old_backend_isas {
+            println!(
+                "cargo:warning=Includes old-backend support for {} ISA",
+                isa.to_string()
+            );
+        }
+        for isa in &new_backend_isas {
+            println!(
+                "cargo:warning=Includes new-backend support for {} ISA",
+                isa.to_string()
+            );
+        }
+        println!(
+            "cargo:warning=Build step took {:?}.",
+            Instant::now() - start_time
+        );
+        println!("cargo:warning=Generated files are in {}", out_dir);
+    }
+
+    #[cfg(feature = "rebuild-peephole-optimizers")]
+    {
+        std::fs::write(
+            std::path::Path::new(&out_dir).join("CRANELIFT_CODEGEN_PATH"),
+            cur_dir.to_str().unwrap(),
+        )
+        .unwrap()
+    }
+}