Add L4Bender as linker variant

Author: humenda

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -77,6 +77,13 @@ impl LinkerInfo {
                     as Box<dyn Linker>
             }
 
+            LinkerFlavor::L4Bender => {
+                Box::new(L4Bender {
+                    cmd,
+                    sess,
+                    hinted_static: false,
+                }) as Box<Linker>
+            },
             LinkerFlavor::Lld(LldFlavor::Wasm) => {
                 Box::new(WasmLd::new(cmd, sess, self)) as Box<dyn Linker>
             }
@@ -1284,6 +1291,127 @@ impl<'a> Linker for WasmLd<'a> {
     }
 }
 
+/// Linker shepherd script for L4Re (Fiasco)
+pub struct L4Bender<'a> {
+    cmd: Command,
+    sess: &'a Session,
+    hinted_static: bool,
+}
+
+impl<'a> Linker for L4Bender<'a> {
+    fn link_dylib(&mut self, lib: &str) {
+        self.link_staticlib(lib); // do not support dynamic linking for now
+    }
+    fn link_staticlib(&mut self, lib: &str) {
+        self.hint_static();
+        self.cmd.arg(format!("-PC{}", lib));
+    }
+    fn link_rlib(&mut self, lib: &Path) {
+        self.hint_static();
+        self.cmd.arg(lib);
+    }
+    fn include_path(&mut self, path: &Path) {
+        self.cmd.arg("-L").arg(path);
+    }
+    fn framework_path(&mut self, _: &Path) {
+        bug!("Frameworks are not supported on L4Re!");
+    }
+    fn output_filename(&mut self, path: &Path) { self.cmd.arg("-o").arg(path); }
+    fn add_object(&mut self, path: &Path) { self.cmd.arg(path); }
+    // not sure about pie on L4Re
+    fn position_independent_executable(&mut self) { }
+    fn no_position_independent_executable(&mut self) { }
+    fn full_relro(&mut self) { self.cmd.arg("-z,relro,-z,now"); }
+    fn partial_relro(&mut self) { self.cmd.arg("-z,relro"); }
+    fn no_relro(&mut self) { self.cmd.arg("-z,norelro"); }
+    fn build_static_executable(&mut self) { self.cmd.arg("-static"); }
+    fn args(&mut self, args: &[String]) { self.cmd.args(args); }
+
+    fn link_rust_dylib(&mut self, lib: &str, _path: &Path) { self.link_dylib(lib); }
+
+    fn link_framework(&mut self, _: &str) {
+        bug!("Frameworks not supported on L4Re.");
+    }
+
+    // Here we explicitly ask that the entire archive is included into the
+    // result artifact. For more details see #15460, but the gist is that
+    // the linker will strip away any unused objects in the archive if we
+    // don't otherwise explicitly reference them. This can occur for
+    // libraries which are just providing bindings, libraries with generic
+    // functions, etc.
+    fn link_whole_staticlib(&mut self, lib: &str, _: &[PathBuf]) {
+        self.hint_static();
+        self.cmd.arg("--whole-archive");
+        self.cmd.arg("-l").arg(lib);
+        self.cmd.arg("--no-whole-archive");
+    }
+
+    fn link_whole_rlib(&mut self, lib: &Path) {
+        self.hint_static();
+        self.cmd.arg("--whole-archive").arg(lib).arg("--no-whole-archive");
+    }
+
+    fn gc_sections(&mut self, keep_metadata: bool) {
+        if !keep_metadata {
+            self.cmd.arg("--gc-sections");
+        }
+    }
+
+    fn optimize(&mut self) {
+        self.cmd.arg("-O2");
+    }
+
+    fn pgo_gen(&mut self) { }
+
+    fn debuginfo(&mut self) {
+        // for documentation, see GccLinker.debuginfo()
+        match self.sess.opts.debuginfo {
+            DebugInfoLevel::NoDebugInfo => {
+                match self.sess.opts.debugging_opts.strip_debuginfo_if_disabled {
+                    Some(true) => { self.cmd.arg("-S"); },
+                    _ => {},
+                }
+            },
+            _ => {},
+        };
+    }
+
+    fn no_default_libraries(&mut self) {
+        self.cmd.arg("-nostdlib");
+    }
+
+    fn build_dylib(&mut self, _: &Path) {
+        bug!("not implemented");
+    }
+
+    fn export_symbols(&mut self, _: &Path, _: CrateType) {
+        bug!("Not implemented");
+    }
+
+    fn subsystem(&mut self, subsystem: &str) {
+        self.cmd.arg(&format!("--subsystem,{}", subsystem));
+    }
+
+    fn finalize(&mut self) -> Command {
+        self.hint_static(); // Reset to default before returning the composed command line.
+        let mut cmd = Command::new("");
+        ::std::mem::swap(&mut cmd, &mut self.cmd);
+        cmd
+    }
+
+    fn group_start(&mut self) { self.cmd.arg("--start-group"); }
+    fn group_end(&mut self) { self.cmd.arg("--end-group"); }
+}
+
+impl<'a> L4Bender<'a> {
+    fn hint_static(&mut self) {
+        if !self.hinted_static {
+            self.cmd.arg("-static");
+            self.hinted_static = true;
+        }
+    }
+}
+
 fn exported_symbols(tcx: TyCtxt<'_>, crate_type: CrateType) -> Vec<String> {
     if let Some(ref exports) = tcx.sess.target.override_export_symbols {
         return exports.clone();

compiler/rustc_target/src/spec/l4re_base.rs

@@ -1,27 +1,16 @@
 use crate::spec::{LinkerFlavor, PanicStrategy, TargetOptions};
 //use std::process::Command;
 
-// Use GCC to locate code for crt* libraries from the host, not from L4Re. Note
-// that a few files also come from L4Re, for these, the function shouldn't be
-// used. This uses GCC for the location of the file, but GCC is required for L4Re anyway.
-//fn get_path_or(filename: &str) -> String {
-//    let child = Command::new("gcc")
-//        .arg(format!("-print-file-name={}", filename)).output()
-//        .expect("Failed to execute GCC");
-//    String::from_utf8(child.stdout)
-//        .expect("Couldn't read path from GCC").trim().into()
-//}
-
 pub fn opts() -> TargetOptions {
     TargetOptions {
         os: "l4re".to_string(),
         env: "uclibc".to_string(),
         linker_flavor: LinkerFlavor::Ld,
         executables: true,
         panic_strategy: PanicStrategy::Abort,
-        linker: Some("ld".to_string()),
-        linker_is_gnu: false,
-        families: vec!["unix".to_string()],
+        linker: Some("l4-bender".to_string()),
+        pre_link_args: args,
+        os_family: Some("unix".to_string()),
         ..Default::default()
     }
 }

compiler/rustc_target/src/spec/x86_64_unknown_l4re_uclibc.rs

@@ -11,6 +11,10 @@ pub fn target() -> Target {
         data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
             .to_string(),
         arch: "x86_64".to_string(),
+        target_os: "l4re".to_string(),
+        target_env: "uclibc".to_string(),
+        target_vendor: "unknown".to_string(),
+        linker_flavor: LinkerFlavor::L4Bender,
         options: base,
     }
 }