fix entrypoint

Signed-off-by: Jorge Prendes <jorge.prendes@gmail.com>

Author: jprendes

src/cargo_cmd.rs

@@ -13,6 +13,7 @@ pub trait CargoCmd {
     fn cc_env(&mut self, triplet: impl AsRef<str>, cc: impl AsRef<Path>) -> &mut Self;
     fn ar_env(&mut self, triplet: impl AsRef<str>, ar: impl AsRef<Path>) -> &mut Self;
     fn sysroot(&mut self, path: impl AsRef<Path>) -> &mut Self;
+    fn entrypoint(&mut self, entry: impl AsRef<str>) -> &mut Self;
     fn append_rustflags(&mut self, flags: impl AsRef<OsStr>) -> &mut Self;
     fn append_cflags(&mut self, triplet: impl AsRef<str>, flags: impl AsRef<OsStr>) -> &mut Self;
     fn append_bindgen_cflags(&mut self, flags: impl AsRef<OsStr>) -> &mut Self;
@@ -102,6 +103,11 @@ impl CargoCmd for Command {
             .append_rustflags(path.as_ref())
     }
 
+    fn entrypoint(&mut self, entry: impl AsRef<str>) -> &mut Self {
+        let entry = entry.as_ref();
+        self.append_rustflags(format!("-Clink-args=-e{entry}"))
+    }
+
     fn append_rustflags(&mut self, flags: impl AsRef<OsStr>) -> &mut Self {
         if flags.as_ref().is_empty() {
             return self;

src/lib.rs

@@ -83,6 +83,7 @@ impl CargoCommandExt for std::process::Command {
     fn populate_from_args(&mut self, args: &Args) -> &mut Self {
         self.target(&args.target);
         self.sysroot(args.sysroot_dir());
+        self.entrypoint("entrypoint");
         if let Some(clang) = &args.clang {
             self.cc_env(&args.target, clang);
         } else {

src/sysroot.rs

@@ -24,7 +24,8 @@ pub fn build(args: &Args) -> Result<()> {
     let target_spec = match args.target.as_str() {
         "x86_64-hyperlight-none" => {
             let mut spec = get_spec(args, "x86_64-unknown-none")?;
-            spec.entry_name = Some("entrypoint".into());
+            // entry_name seems to be ignored, use RUSTFLAGS with -Clink-args=-eentrypoint instead
+            //spec.entry_name = Some("entrypoint".into());
             spec.code_model = Some("small".into());
             spec.linker = Some("rust-lld".into());
             spec.linker_flavor = Some("gnu-lld".into());