Support -Zbuild-std

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+* Support `-Zbuild-std`.
+
 ### Fixed
 
 ### Changed

src/dependencies.rs

@@ -78,6 +78,26 @@ fn cfgs(config: &Config) -> Result<Vec<Cfg>, Errored> {
     Ok(cfgs)
 }
 
+pub(crate) fn has_build_std(info: &DependencyBuilder) -> bool {
+    let mut args = info.program.args.iter();
+
+    while let Some(arg) = args.next() {
+        if arg == "-Z" {
+            if let Some(arg) = args.next().map(|arg| arg.to_string_lossy()) {
+                if arg.starts_with("build-std") {
+                    return true;
+                }
+            }
+        }
+
+        if arg.to_string_lossy().starts_with("-Zbuild-std") {
+            return true;
+        }
+    }
+
+    false
+}
+
 /// Compiles dependencies and returns the crate names and corresponding rmeta files.
 fn build_dependencies_inner(
     config: &Config,
@@ -166,15 +186,18 @@ fn build_dependencies_inner(
                     .target
                     .crate_types
                     .iter()
-                    .all(|ctype| !matches!(ctype.as_str(), "proc-macro" | "lib"))
+                    .all(|ctype| !matches!(ctype.as_str(), "proc-macro" | "lib" | "rlib"))
                 {
                     continue;
                 }
                 for filename in &artifact.filenames {
                     import_paths.insert(filename.parent().unwrap().into());
                 }
                 let package_id = artifact.package_id;
-                if let Some(prev) = artifacts.insert(package_id.clone(), Ok(artifact.filenames)) {
+                if let Some(prev) = artifacts.insert(
+                    package_id.clone(),
+                    Ok((artifact.target.name, artifact.filenames)),
+                ) {
                     artifacts.insert(
                         package_id.clone(),
                         Err(format!(
@@ -252,7 +275,7 @@ fn build_dependencies_inner(
             .unwrap();
 
         // Then go over all of its dependencies
-        let dependencies = root
+        let mut dependencies = root
             .dependencies
             .iter()
             .filter(|dep| matches!(dep.kind, DependencyKind::Normal))
@@ -284,7 +307,7 @@ fn build_dependencies_inner(
                 let id = &package.id;
                 // Return the name chosen in `Cargo.toml` and the path to the corresponding artifact
                 match artifacts.remove(id) {
-                    Some(Ok(artifacts)) => Some(Ok((name.replace('-', "_"), artifacts))),
+                    Some(Ok((_, artifacts))) => Some(Ok((name.replace('-', "_"), artifacts))),
                     Some(Err(what)) => Some(Err(Errored {
                         command: Command::new(what),
                         errors: vec![],
@@ -306,6 +329,28 @@ fn build_dependencies_inner(
             .collect::<Result<Vec<_>, Errored>>()?;
         let import_paths = import_paths.into_iter().collect();
         let import_libs = import_libs.into_iter().collect();
+
+        if has_build_std(info) {
+            let mut build_std_crates = HashSet::new();
+            build_std_crates.insert("core");
+            build_std_crates.insert("alloc");
+            build_std_crates.insert("proc_macro");
+            build_std_crates.insert("panic_unwind");
+            build_std_crates.insert("compiler_builtins");
+            build_std_crates.insert("std");
+            build_std_crates.insert("test");
+            build_std_crates.insert("panic_abort");
+
+            for (name, artifacts) in artifacts
+                .into_iter()
+                .filter_map(|(_, artifacts)| artifacts.ok())
+            {
+                if build_std_crates.remove(name.as_str()) {
+                    dependencies.push((format!("noprelude:{name}"), artifacts));
+                }
+            }
+        }
+
         return Ok(Dependencies {
             dependencies,
             import_paths,
@@ -381,6 +426,11 @@ pub fn build_dependencies(
 ) -> Result<Vec<OsString>, Errored> {
     let dependencies = build_dependencies_inner(config, info)?;
     let mut args = vec![];
+
+    if has_build_std(info) {
+        args.push("-Zunstable-options".into());
+    }
+
     for (name, artifacts) in dependencies.dependencies {
         for dependency in artifacts {
             args.push("--extern".into());