Rollup merge of rust-lang#48725 - humenda:master, r=nikomatsakis

Update L4Re target specification

Due to the dynamically generated linker arguments of the L4Re build system, it is not a good idea to hard-code them in Rust. This PR undoes this step. It also adds an empty implementation to retrieve the number of CPUs.

src/librustc_back/target/l4re_base.rs

@@ -8,74 +8,35 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use PanicStrategy;
 use LinkerFlavor;
+use PanicStrategy;
 use target::{LinkArgs, TargetOptions};
 use std::default::Default;
-use std::env;
-use std::process::Command;
+//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()
-}
+//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() -> Result<TargetOptions, String> {
-    let l4re_lib_path = env::var_os("L4RE_LIBDIR").ok_or("Unable to find L4Re \
-        library directory: L4RE_LIBDIR not set.")?.into_string().unwrap();
-    let mut pre_link_args = LinkArgs::new();
-    pre_link_args.insert(LinkerFlavor::Ld, vec![
-        format!("-T{}/main_stat.ld", l4re_lib_path),
-        "--defsym=__executable_start=0x01000000".to_string(),
-        "--defsym=__L4_KIP_ADDR__=0x6ffff000".to_string(),
-        format!("{}/crt1.o", l4re_lib_path),
-        format!("{}/crti.o", l4re_lib_path),
-        get_path_or("crtbeginT.o"),
-    ]);
-    let mut post_link_args = LinkArgs::new();
-    post_link_args.insert(LinkerFlavor::Ld, vec![
-        format!("{}/l4f/libpthread.a", l4re_lib_path),
-        format!("{}/l4f/libc_be_sig.a", l4re_lib_path),
-        format!("{}/l4f/libc_be_sig_noop.a", l4re_lib_path),
-        format!("{}/l4f/libc_be_socket_noop.a", l4re_lib_path),
-        format!("{}/l4f/libc_be_fs_noop.a", l4re_lib_path),
-        format!("{}/l4f/libc_be_sem_noop.a", l4re_lib_path),
-        format!("{}/l4f/libl4re-vfs.o.a", l4re_lib_path),
-        format!("{}/l4f/lib4re.a", l4re_lib_path),
-        format!("{}/l4f/lib4re-util.a", l4re_lib_path),
-        format!("{}/l4f/libc_support_misc.a", l4re_lib_path),
-        format!("{}/l4f/libsupc++.a", l4re_lib_path),
-        format!("{}/l4f/lib4shmc.a", l4re_lib_path),
-        format!("{}/l4f/lib4re-c.a", l4re_lib_path),
-        format!("{}/l4f/lib4re-c-util.a", l4re_lib_path),
-        get_path_or("libgcc_eh.a"),
-        format!("{}/l4f/libdl.a", l4re_lib_path),
-        "--start-group".to_string(),
-        format!("{}/l4f/libl4util.a", l4re_lib_path),
-        format!("{}/l4f/libc_be_l4re.a", l4re_lib_path),
-        format!("{}/l4f/libuc_c.a", l4re_lib_path),
-        format!("{}/l4f/libc_be_l4refile.a", l4re_lib_path),
-        "--end-group".to_string(),
-        format!("{}/l4f/libl4sys.a", l4re_lib_path),
-        "-gc-sections".to_string(),
-        get_path_or("crtend.o"),
-        format!("{}/crtn.o", l4re_lib_path),
-    ]);
+pub fn opts() -> TargetOptions {
+    let mut args = LinkArgs::new();
+    args.insert(LinkerFlavor::Gcc, vec![]);
 
-    Ok(TargetOptions {
+    TargetOptions {
         executables: true,
         has_elf_tls: false,
         exe_allocation_crate: None,
         panic_strategy: PanicStrategy::Abort,
-        pre_link_args,
-        post_link_args,
+        linker: Some("ld".to_string()),
+        pre_link_args: args,
         target_family: Some("unix".to_string()),
         .. Default::default()
-    })
+    }
 }

src/librustc_back/target/x86_64_unknown_l4re_uclibc.rs

@@ -12,7 +12,7 @@ use LinkerFlavor;
 use target::{Target, TargetResult};
 
 pub fn target() -> TargetResult {
-    let mut base = super::l4re_base::opts()?;
+    let mut base = super::l4re_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
 

src/libtest/lib.rs

@@ -1294,6 +1294,12 @@ fn get_concurrency() -> usize {
         // FIXME: implement
         1
     }
+
+    #[cfg(target_os = "l4re")]
+    fn num_cpus() -> usize {
+        // FIXME: implement
+        1
+    }
 }
 
 pub fn filter_tests(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> Vec<TestDescAndFn> {