Merge #199

199: Rework features r=stlankes a=mkroening



Co-authored-by: Martin Kröning <mkroening@posteo.net>

Author: bors[bot]

hermit-sys/Cargo.toml

@@ -14,19 +14,28 @@ edition = "2021"
 documentation = "https://hermitcore.github.io/rusty-hermit/hermit_sys"
 
 [features]
-default = ["pci", "acpi", "smp", "fsgsbase"]
-# controls whether RustyHermit is build with -Z instrument-mcount
-instrument = ["rftrace"]
-trace = []
+default = [
+    "acpi",
+    "pci",
+    "smp",
+    "fsgsbase",
+]
+
+aarch64-qemu-stdout = []
+acpi = []
+dhcpv4 = ["smoltcp/proto-dhcpv4"]
 fsgsbase = []
+
+# Build the kernel with function instrument code for mcount-based tracing
+instrument = ["rftrace"]
+
 pci = []
-acpi = []
+smp = []
+trace = []
 vga = []
-dhcpv4 = ["smoltcp/proto-dhcpv4"]
-# only for internal usage, please don't use it
+
+# Internal feature for building the kernel from local sources
 with_submodule = []
-smp = []
-aarch64-qemu-stdout = []
 
 [build-dependencies]
 walkdir = "2"

hermit-sys/build.rs

@@ -10,6 +10,23 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 use walkdir::{DirEntry, WalkDir};
 
+macro_rules! forward_features {
+	($cmd:expr, $($feature:literal,)+ ) => {
+		let mut features = vec![];
+
+		$(
+			if cfg!(feature = $feature) {
+				features.push($feature);
+			}
+		)+
+
+		if !features.is_empty() {
+			$cmd.arg("--features");
+			$cmd.arg(features.join(" "));
+		}
+	};
+}
+
 fn build_hermit(src_dir: &Path, target_dir_opt: Option<&Path>) {
 	let manifest_path = src_dir.join("Cargo.toml");
 	assert!(
@@ -59,49 +76,17 @@ fn build_hermit(src_dir: &Path, target_dir_opt: Option<&Path>) {
 		cmd.arg("--release");
 	}
 
-	// disable all default features
+	// Control enabled features via this crate's features
 	cmd.arg("--no-default-features");
-
-	#[cfg(feature = "aarch64-qemu-stdout")]
-	{
-		cmd.arg("--features");
-		cmd.arg("aarch64-qemu-stdout");
-	}
-
-	// do we have to enable PCI support?
-	#[cfg(feature = "pci")]
-	{
-		cmd.arg("--features");
-		cmd.arg("pci");
-	}
-
-	// do we have to enable acpi support?
-	#[cfg(feature = "acpi")]
-	{
-		cmd.arg("--features");
-		cmd.arg("acpi");
-	}
-
-	// do we have to enable FSGSBASE support?
-	#[cfg(feature = "fsgs_base")]
-	{
-		cmd.arg("--features");
-		cmd.arg("fsgs_base");
-	}
-
-	// do we support multi-processor systems?
-	#[cfg(feature = "smp")]
-	{
-		cmd.arg("--features");
-		cmd.arg("smp");
-	}
-
-	// do we have to enable VGA support
-	#[cfg(feature = "vga")]
-	{
-		cmd.arg("--features");
-		cmd.arg("vga");
-	}
+	forward_features!(
+		cmd,
+		"aarch64-qemu-stdout",
+		"acpi",
+		"fsgsbase",
+		"pci",
+		"smp",
+		"vga",
+	);
 
 	let mut rustflags = vec!["-Zmutable-noalias=no".to_string()];
 	let outer_rustflags = env::var("CARGO_ENCODED_RUSTFLAGS").unwrap();