L4Re: Repair build and move to rustc linking

Fixes the builds of rustc and library/std for the L4Re target OS.
A major change was done in linking binaries: The need for the L4Bender
tool was removed and linking parameters are now fully configured in the
rustc target config.

Author: farao

compiler/rustc_codegen_ssa/messages.ftl

@@ -1,5 +1,3 @@
-codegen_ssa_L4Bender_exporting_symbols_unimplemented = exporting symbols not implemented yet for L4Bender
-
 codegen_ssa_aarch64_softfloat_neon = enabling the `neon` target feature on the current target is unsound due to ABI issues
 
 codegen_ssa_add_native_library = failed to add native library {$library_path}: {$error}

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -137,9 +137,6 @@ pub(crate) fn get_linker<'a>(
     // to the linker args construction.
     assert!(cmd.get_args().is_empty() || sess.target.abi == Abi::Uwp);
     match flavor {
-        LinkerFlavor::Unix(Cc::No) if sess.target.os == Os::L4Re => {
-            Box::new(L4Bender::new(cmd, sess)) as Box<dyn Linker>
-        }
         LinkerFlavor::Unix(Cc::No) if sess.target.os == Os::Aix => {
             Box::new(AixLinker::new(cmd, sess)) as Box<dyn Linker>
         }
@@ -280,7 +277,6 @@ generate_arg_methods! {
     MsvcLinker<'_>
     EmLinker<'_>
     WasmLd<'_>
-    L4Bender<'_>
     AixLinker<'_>
     LlbcLinker<'_>
     PtxLinker<'_>
@@ -1475,128 +1471,6 @@ impl<'a> WasmLd<'a> {
     }
 }
 
-/// Linker shepherd script for L4Re (Fiasco)
-struct L4Bender<'a> {
-    cmd: Command,
-    sess: &'a Session,
-    hinted_static: bool,
-}
-
-impl<'a> Linker for L4Bender<'a> {
-    fn cmd(&mut self) -> &mut Command {
-        &mut self.cmd
-    }
-
-    fn set_output_kind(
-        &mut self,
-        _output_kind: LinkOutputKind,
-        _crate_type: CrateType,
-        _out_filename: &Path,
-    ) {
-    }
-
-    fn link_staticlib_by_name(&mut self, name: &str, _verbatim: bool, whole_archive: bool) {
-        self.hint_static();
-        if !whole_archive {
-            self.link_arg(format!("-PC{name}"));
-        } else {
-            self.link_arg("--whole-archive")
-                .link_or_cc_arg(format!("-l{name}"))
-                .link_arg("--no-whole-archive");
-        }
-    }
-
-    fn link_staticlib_by_path(&mut self, path: &Path, whole_archive: bool) {
-        self.hint_static();
-        if !whole_archive {
-            self.link_or_cc_arg(path);
-        } else {
-            self.link_arg("--whole-archive").link_or_cc_arg(path).link_arg("--no-whole-archive");
-        }
-    }
-
-    fn full_relro(&mut self) {
-        self.link_args(&["-z", "relro", "-z", "now"]);
-    }
-
-    fn partial_relro(&mut self) {
-        self.link_args(&["-z", "relro"]);
-    }
-
-    fn no_relro(&mut self) {
-        self.link_args(&["-z", "norelro"]);
-    }
-
-    fn gc_sections(&mut self, keep_metadata: bool) {
-        if !keep_metadata {
-            self.link_arg("--gc-sections");
-        }
-    }
-
-    fn optimize(&mut self) {
-        // GNU-style linkers support optimization with -O. GNU ld doesn't
-        // need a numeric argument, but other linkers do.
-        if self.sess.opts.optimize == config::OptLevel::More
-            || self.sess.opts.optimize == config::OptLevel::Aggressive
-        {
-            self.link_arg("-O1");
-        }
-    }
-
-    fn pgo_gen(&mut self) {}
-
-    fn debuginfo(&mut self, strip: Strip, _: &[PathBuf]) {
-        match strip {
-            Strip::None => {}
-            Strip::Debuginfo => {
-                self.link_arg("--strip-debug");
-            }
-            Strip::Symbols => {
-                self.link_arg("--strip-all");
-            }
-        }
-    }
-
-    fn no_default_libraries(&mut self) {
-        self.cc_arg("-nostdlib");
-    }
-
-    fn export_symbols(&mut self, _: &Path, _: CrateType, _: &[(String, SymbolExportKind)]) {
-        // ToDo, not implemented, copy from GCC
-        self.sess.dcx().emit_warn(errors::L4BenderExportingSymbolsUnimplemented);
-    }
-
-    fn windows_subsystem(&mut self, subsystem: WindowsSubsystemKind) {
-        let subsystem = subsystem.as_str();
-        self.link_arg(&format!("--subsystem {subsystem}"));
-    }
-
-    fn reset_per_library_state(&mut self) {
-        self.hint_static(); // Reset to default before returning the composed command line.
-    }
-
-    fn linker_plugin_lto(&mut self) {}
-
-    fn control_flow_guard(&mut self) {}
-
-    fn ehcont_guard(&mut self) {}
-
-    fn no_crt_objects(&mut self) {}
-}
-
-impl<'a> L4Bender<'a> {
-    fn new(cmd: Command, sess: &'a Session) -> L4Bender<'a> {
-        L4Bender { cmd, sess, hinted_static: false }
-    }
-
-    fn hint_static(&mut self) {
-        if !self.hinted_static {
-            self.link_or_cc_arg("-static");
-            self.hinted_static = true;
-        }
-    }
-}
-
 /// Linker for AIX.
 struct AixLinker<'a> {
     cmd: Command,

compiler/rustc_codegen_ssa/src/errors.rs

@@ -113,10 +113,6 @@ pub(crate) struct Ld64UnimplementedModifier;
 #[diag(codegen_ssa_linker_unsupported_modifier)]
 pub(crate) struct LinkerUnsupportedModifier;
 
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_L4Bender_exporting_symbols_unimplemented)]
-pub(crate) struct L4BenderExportingSymbolsUnimplemented;
-
 #[derive(Diagnostic)]
 #[diag(codegen_ssa_no_natvis_directory)]
 pub(crate) struct NoNatvisDirectory {

compiler/rustc_target/src/spec/base/l4re.rs

@@ -1,14 +1,59 @@
-use crate::spec::{Cc, Env, LinkerFlavor, Os, PanicStrategy, RelocModel, TargetOptions, cvs};
+use crate::spec::{
+    Cc, Env, LinkOutputKind, LinkSelfContainedComponents, LinkSelfContainedDefault, LinkerFlavor,
+    Os, PanicStrategy, TargetOptions, add_link_args, crt_objects, cvs,
+};
 
 pub(crate) fn opts() -> TargetOptions {
+    // add ld- and cc-style args
+    macro_rules! prepare_args {
+        ($($val:expr),+) => {{
+            let ld_args = &[$($val),+];
+            let cc_args = &[$(concat!("-Wl,", $val)),+];
+
+            let mut ret = TargetOptions::link_args(LinkerFlavor::Unix(Cc::No), ld_args);
+            add_link_args(&mut ret, LinkerFlavor::Unix(Cc::Yes), cc_args);
+            ret
+        }};
+    }
+
+    let pre_link_args = prepare_args!("-nostdlib", "-dynamic-linker=rom/libld-l4.so");
+
+    let late_link_args = prepare_args!("-lc", "-lgcc_eh");
+
+    let pre_link_objects_self_contained = crt_objects::new(&[
+        (LinkOutputKind::StaticNoPicExe, &["crt1.o", "crti.o", "crtbeginT.o"]),
+        (LinkOutputKind::StaticPicExe, &["crt1.p.o", "crti.o", "crtbegin.o"]),
+        (LinkOutputKind::DynamicNoPicExe, &["crt1.o", "crti.o", "crtbegin.o"]),
+        (LinkOutputKind::DynamicPicExe, &["crt1.s.o", "crti.o", "crtbeginS.o"]),
+        (LinkOutputKind::DynamicDylib, &["crti.s.o", "crtbeginS.o"]),
+        (LinkOutputKind::StaticDylib, &["crti.s.o", "crtbeginS.o"]),
+    ]);
+
+    let post_link_objects_self_contained = crt_objects::new(&[
+        (LinkOutputKind::StaticNoPicExe, &["crtendT.o", "crtn.o"]),
+        (LinkOutputKind::StaticPicExe, &["crtend.o", "crtn.o"]),
+        (LinkOutputKind::DynamicNoPicExe, &["crtend.o", "crtn.o"]),
+        (LinkOutputKind::DynamicPicExe, &["crtendS.o", "crtn.o"]),
+        (LinkOutputKind::DynamicDylib, &["crtendS.o", "crtn.s.o"]),
+        (LinkOutputKind::StaticDylib, &["crtendS.o", "crtn.s.o"]),
+    ]);
+
     TargetOptions {
         os: Os::L4Re,
         env: Env::Uclibc,
-        linker_flavor: LinkerFlavor::Unix(Cc::No),
-        panic_strategy: PanicStrategy::Abort,
-        linker: Some("l4-bender".into()),
         families: cvs!["unix"],
-        relocation_model: RelocModel::Static,
+        panic_strategy: PanicStrategy::Abort,
+        linker_flavor: LinkerFlavor::Unix(Cc::No),
+        dynamic_linking: true,
+        position_independent_executables: true,
+        has_thread_local: true,
+        pre_link_args,
+        late_link_args,
+        pre_link_objects_self_contained,
+        post_link_objects_self_contained,
+        link_self_contained: LinkSelfContainedDefault::WithComponents(
+            LinkSelfContainedComponents::LIBC | LinkSelfContainedComponents::CRT_OBJECTS,
+        ),
         ..Default::default()
     }
 }

compiler/rustc_target/src/spec/targets/x86_64_unknown_l4re_uclibc.rs

@@ -1,11 +1,13 @@
-use crate::spec::{Arch, PanicStrategy, Target, TargetMetadata, base};
+use crate::spec::{Arch, Cc, LinkerFlavor, Target, TargetMetadata, base};
 
 pub(crate) fn target() -> Target {
     let mut base = base::l4re::opts();
     base.cpu = "x86-64".into();
     base.plt_by_default = false;
     base.max_atomic_width = Some(64);
-    base.panic_strategy = PanicStrategy::Abort;
+    let extra_link_args = &["-zmax-page-size=0x1000", "-zcommon-page-size=0x1000"];
+    base.add_pre_link_args(LinkerFlavor::Unix(Cc::Yes), extra_link_args);
+    base.add_pre_link_args(LinkerFlavor::Unix(Cc::No), extra_link_args);
 
     Target {
         llvm_target: "x86_64-unknown-l4re-gnu".into(),

library/Cargo.lock

@@ -146,9 +146,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.178"
+version = "0.2.179"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37c93d8daa9d8a012fd8ab92f088405fb202ea0b6ab73ee2482ae66af4f42091"
+checksum = "c5a2d376baa530d1238d133232d15e239abad80d05838b4b59354e5268af431f"
 dependencies = [
  "rustc-std-workspace-core",
 ]

library/panic_unwind/src/lib.rs

@@ -41,11 +41,6 @@ cfg_select! {
         #[path = "hermit.rs"]
         mod imp;
     }
-    target_os = "l4re" => {
-        // L4Re is unix family but does not yet support unwinding.
-        #[path = "dummy.rs"]
-        mod imp;
-    }
     any(
         all(target_family = "windows", target_env = "gnu"),
         target_os = "psp",

library/std/Cargo.toml

@@ -33,7 +33,7 @@ miniz_oxide = { version = "0.8.0", optional = true, default-features = false }
 addr2line = { version = "0.25.0", optional = true, default-features = false }
 
 [target.'cfg(not(all(windows, target_env = "msvc")))'.dependencies]
-libc = { version = "0.2.178", default-features = false, features = [
+libc = { version = "0.2.179", default-features = false, features = [
     'rustc-dep-of-std',
 ], public = true }
 

library/std/src/net/tcp.rs

@@ -7,6 +7,7 @@
         all(target_os = "wasi", target_env = "p1"),
         target_os = "xous",
         target_os = "trusty",
+        target_os = "l4re",
     ))
 ))]
 mod tests;

library/std/src/net/udp.rs

@@ -6,6 +6,7 @@
         target_env = "sgx",
         target_os = "xous",
         target_os = "trusty",
+        target_os = "l4re",
     ))
 ))]
 mod tests;